3. Methods
In this section will be present all the details of the Project, starting from the plant characteristics where is define all the choices make inside the system, passing through the automatic systems implemented inside the controllers and finishing to describe the interface used to control in an accessible means the CNC machine.
3.1. Plant characteristics
Figure 9. Simulate plant. (From P2C, 2017)
This extensive system was projected to work in the nautical industry but at the same time can be used in other production fields; such as car building, furnishings, customized pieces, etc. As long as the desired sample respects the dimensions of the robot operating space (50x8x4 meters) it’s possible to shape any 3D model. Briefly, can compare to a big 3D printer except that CNC machining starts with a block of stock material and shapes it with a rotating tool, carving away excess until the finished
practices. In Italy, the trend for boat building is the hand-made or the fiberglass print. The second case is possible once the model of the boat has been designed. So, the solution propose in this work can be a good alternative to power up the sector and develop effective solutions.
This one is an 8-axis robotized plant for milling and sanding large surfaces. In particular, is composed by a 6-degree anthropomorphic robot supplied by Kuka, model KR90 R3100 extra C, that is placed on a ceiling linear slider of 8 meters in length. This slider is driven by an electric motor controlled by the Kuka robot controller (KRC). The longitudinal sliders are installed on a portal of equal width and characterized by a height of 4 meters. This portal moves on two parallel guides supplied by Güdel with a length of 50 meters, driven by two electric motors controlled by the Kuka controller as additional external axes to the anthropomorphic robot.
The robot work-space is equipped with: a tool and head storage to perform different machining operations; The heads provided are: electro-spindle for the milling processes and a sander for the stock material finishes; electro-spindle communicates with the PLC via CANopen protocol and sander provides a force sensor used by the Kuka arm control system; the quick release system for the automatic head and tools change is provided on the robot; the system is controlled by a system management software installed on a PLC in a control room.
Is possible to define the plant as the union of various subsystems controlled indep-endently or by a central controller. Some of the relevant subsytems are 1) a Spindle mounted on the TCP (Tool Center Point) of the robot, that permits the robot to model the piece of stock material; 2) a robot KR90 R3100 extra C, moved in different positions of the workcell to execute the programmed activities; 3) three sliders, add 2-axis movement and permit the robot move transversally and longitudinally, 4) three lubrication systems, placed on the sliders to reduce the friction between the moving parts; 5) some pressure valves, used by the robot and the spindle to clamp the different tools and heads necessary to do the milling and sanding operation; 6) an Inverter used to control the sander and spindle head, 7) an HMI (Human-Macchine Interface) panel, let operators interact with computers in a novel ways from a high level control giving also some feedback signals to diagnostic the different states where the plant can be situated, 8) some digital inputs/outputs of the sensors placed on the tool/head storage; and the most important component in this group 9) a PLC, manage the communication of the different signals, transmitted for one subsystem to another. Hence, the system that collects the information and after that process the data, to activate the different programmed tasks. It is possible to have a look in the cabinet layout and some of the plant connections in Figure 10.
The strength of the plant is the control and management system, in order to monitor production and process targets. This management tool allows operators and line supervisors to control and coordinate the industrial and manufacturing processes of the plant in a friendly way.
3.2. ROBOT
3.2.1 Description of the robot
Figure 11. Electrical cabinet layout. (From KUKA, 2016)[21]
The robot system includes all the construction groups of an industrial robot such: manipulator (robot mechanics with electrical installation), control cabinet, connection cables, tool and equipment. The KR QUANTEC extra HA product line includes the following models:
KR 90 R3100 extra HA
Industrial robots include different components apart from the robot as manipulator, Connection cables, KCP programming terminal (KUKA smartPAD), Software and the Options, accessories. In Figure 12 is shown the complete components used for this project.
1. Manipulator. 2. Connection cables. 3. Robot control.
4. KUKA smartPAD programming terminal.
The manipulators (robot arm and electrical installations) of the variants are designed as 6-axis jointed-arm kinematic systems. They consist of the following principal components: • In-line wrist • Arm • Link arm • Rotating column • Base frame • Counterbalancing system • Electrical Installations
Figure 13. Main assemblies of the manipulator.(From KUKA, 2018)[23]
mounting flange conforms, with minimal deviations, to DIN/ISO9409-1-A and meets the requirements of IP65.
2) Arm
The arm is the link between the in-line wrist and the link arm. It houses the motors of wrist axes 4 and 5. The arm is driven by the motor of axis 3. The maximum permissible swivel angle is mechanically limited by a stop for each direction, plus and minus. The associated buffers are attached to the arm. There is an interface on the arm with 4 holes for fastening supplementary loads.
3) Counterbalancing system
The counterbalancing system is installed between the rotating column and the link arm and serves to minimize the moments generated about axis 2 when the robot is in motion and at rest. A closed, hydro-pneumatic system is used. The system consists of two accumulators, a hydraulic cylinder with associated hoses, a pressure gauge and a bursting disc as a safety element to protect against overload. The accumulators are classified below category I, fluid group 2, of the Pressure Equipment Directive.
4) Electrical Installations
The electrical installations include all the motor and data cables for the motors of axes 1 to 6. All connections are implemented as connectors in order to enable the motors to be exchanged quickly and reliably. The electrical installations also include the RDC box and the multi-function housing (MFH). The RDC box is located in the rotating column. The MFH and the connector for the data cables are mounted on the robot base frame. The connecting cables from the robot controller are connected here by means of connectors. The electrical installations also include a protective circuit.
5) Base frame
The base frame is the base of the robot. It is screwed to the mounting base. The flexible tube for the electrical installations is fastened in the base frame. Also located on the base frame is the interface for the motor and data cable and the energy supply system.
6) Rotating column
The rotating column houses the motors of axes 1 and 2. The rotational motion of axis 1 is performed by the rotating column. This is screwed to the base frame via the gear unit of axis 1 and is driven by a motor in the rotating column. The link arm is also mounted in the rotating column.
7) Link arm
The link arm is the assembly located between the arm and the rotating column. It consists of the link arm body with the buffers for axis 2. In combination with the arm, there are two different lengths of link arm available to obtain the specified reach. There is an interface on the link arm with 4 holes for fastening supplementary loads.[24]
3.2.2. Technical robot data, KR 90 R3100 extra HA
• Basic data
Table 1. KR 90 R3100 extra HA technical data.
• Ambient conditions
• Connecting cables
Table 3. KR 90 R3100 extra HA connectinf cables.
Table 4. KR 90 R3100 extra HA motion ranges. • Working space
Figure 16. Working envelope, top view(from KUKA, 2018)[27]
3.2.3. Profinet communication
The PROFINET is a high-level network for industrial automation applications. Built on standard Ethernet technologies, PROFINET IO uses traditional Ethernet hardware and software to define a network that structures the task of exchanging data, alarms and diagnostics with Programmable Controllers and other automation controllers.
PROFINET focuses on Programmable Controller data exchange, PROFInet CBA (Component Based Automation) focuses on distributed automation systems.
This fieldbus is very similar to Profibus on Ethernet. While Profibus uses cyclic communications to exchange data with Programmable Controllers at a maximum speed of 12Meg baud PROFINET IO uses cyclic data transfer to exchange data with Programmable Controllers over Ethernet. As with Profibus, a Programmable Controller and a device must both have a prior understanding of the data structure and meaning. In both systems data is organized as slots containing modules with the total number of I/O points for a system the sum of the I/O points for the individual modules.
It uses three different communication channels to exchange data with programmable Controllers and other devices. The standard TCP/IP channel is used for parameterization, configuration and acyclic read/write operations. The RT or Real Time channel is used for standard cyclic data transfer and alarms. RT communications bypass the standard TCP/IP interface to expedite the data exchange with Programmable Controllers. The third channel, Isochronous Real Time (IRT) is the very high-speed channel used for Motion Control applications. IRT is implemented using a custom ASIC and is not the subject of this paper[28].
There are many Industrial Ethernets to choose from good reasons to chose the PROFINET fieldbus are the follows:
Adoption – PROFINET has the largest installed base of any Industrial Ethernet. And it is growing faster than number two globally and in North America. Having the largest installed base attracts additional users and additional vendors. Expect a broad variety of products, diagnostic tools, and services as a result. GE Intelligent Platforms, Siemens, and Phoenix Contact have established PROFINET as their exclusive backbone and most other controller suppliers offer PROFINET connectivity as well.
Speed – Whether you need update speeds in the hundreds of milliseconds or in fractions of a millisecond, PROFINET provides it. This makes PROFINET suitable for slower systems sometimes found in process applications and in very fast systems needed for high speed IO and motion control. One network does it all; there is no need for a separate IO network and a different motion control network. This simplifies configuration and diagnostics. And installers and maintenance folks only have one network to be trained on.
Diagnostics – Like PROFIBUS, PROFINET provides diagnostics at the device, module, and channel levels. So you are alerted if an IO rack becomes disconnected or defective; if a module stops working; or if one input on a module has a problem. For example, if a digital output is indicated as on but no current is flowing, you are alerted. Ethernet protocols like Simple Network Management Protocol (SNMP) are used to extract data from Ethernet switches whether those switches are standalone Ethernet switches or switches built into automation devices. Diagnostics prevent downtime[29].
3.2.4. Robot programming, WorkVisual
The KUKA WorkVisual program code is already checked for logic in the background while programming steps are being carried out. This means that errors are nipped in the bud, and projects can be implemented more efficiently and consistently. Interactions are made visible by visual tools – making them more intuitive and easier to operate[28].
The WorkVisual software package is the an environment for KR C4 controlled robotic cells. From this program is possible to control the hand-shake functions between the PLC-Robot. Besides It allows the I/O handling of the robot, a complete robot cell or line of robots. It offers the following functionalities:
• Configuring and connecting field buses • Programming robots offline
• Configuring machine data • Configuring RoboTeams offline • Editing the safety configuration
• Editing TOOL and BASE coordinate systems • Defining robot cells online
• Managing option packages • Diagnostic functionality
• Online display of system information about the robot controller
• Configuring traces, starting recordings, evaluating traces (with the oscilloscope)
Figure 17. WorkVisual graphical user interface.(From KUKA, 2018)[30]
Project structure window
The Project structure window contains the following tabs:
• Hardware: The Hardware tab shows the relationship between the various devices. Here, the individual devices can be assigned to a robot controller. One of the most important feature of this tab is the Editing field bus signal, the PROFINET field bus signals can be edited in WorkVisual. For example, the signal type, the signal width can be changed or the byte order can be swapped.
Figure 18. Signal Editor (from KUKA, G. 2018)[31]
1) The left-hand column displays the original configuration of the inputs or outputs. Each box represents 1 bit.
2) The right-hand column can be edited and always displays the current configuration of the inputs or outputs. Each box represents 1 bit. 3) Signal name.
4) Start mark for swapping.
5) Address at which this signal starts. 6) Signal width.
7) Address to which this bit belongs, and number of the bit. 8) The bar indicates that the byte order has been swapped. 9) Boundary between memory segments.
information travel to one system to another through the Profinet fieldbus. Is possible to set 1024 inputs and 1024 outputs.
In the tables below are exposed a short list of the variables used for this project:
o KR C I/O / I/O / Digital inputs Fieldbus / PROFINET
Name Type Description Name Description
$IN[1] BOOL In_ToolsHomeID Tool_HomeID Number of tool home where the robot needs to go $IN[2] BOOL In_HeadsHomeID Head_HomeID Number of head home where the robot needs to go
$IN[3] BOOL MOVE_ENABLE MOVE_ENABLE Enable the
manual or
automatic
movement of the robot
$IN[4] UINT PGNO PGNO Program number
operation
$IN[5] UINT In_ Tool_rqt Tool_rqt Tool request for processing $IN[6] UINT In_Head_rqt Head_rqt Head request for
processing
$IN[7] BOOL DRIVES_ON DRIVES_ON Activate the
drives of the motors placed on the joints
Table 5. PROFINET sample of the robot digital inputs.
o KR C I/O / I/O / Digital outputs Fieldbus / PROFINET
Name Type Description Name Description
$OUT[1] BOOL Out_ToolsHomeID ToolsHomeID Number of tool home where the robot has gone $OUT[2] BOOL Out_ToolHolder ToolHolder Number of tool
robot has gone $OUT[3] BOOL Out_HeadsHomeID HeadsHomeID Number of head
home where the robot has gone $OUT[4] BOOL Out_HeadHolder HeadHolder Number of head
holder where the robot has gone
$OUT[5] BOOL PGNO_REQ PGNO_REQ Program number
request
$OUT[6] BOOL APPL_RUN APPL_RUN Robot program
running
$OUT[7] BOOL IN_HOME IN_HOME The robot is in home position
Table 6. PROFINET sample of the robot digital outputs.
• Geometry: The Geometry tab displays all the geometrical objects used in the project in a tree structure (kinematic systems, tools, base objects). The properties of the objects can be edited. If objects need to be linked geometrically, e.g. if a robot is to be assigned to a KUKA linear unit: this must be done here on the Geometry tab.
•
Files: The Files tab contains the program and configuration files belonging to the project. All the programs wrote to allow the hand-shake between the PLC and the robot for the operation of the CNC machine are in this section. In this area has been implement some hand-shake functions:-Go to home outside storage -Go to the general home -Go to heads Holder ID -Go to heads Home ID -Go to tools Holder ID -Go to tools Home ID -Load head
&ACCESS RVO1 &REL 11
&PARAM DISKPATH = KRC:\R1\Program\Tools\Load DEF Load_tool( )
;FOLD INI;%{PE} ;FOLD BASISTECH INI
GLOBAL INTERRUPT DECL 3 WHEN $STOPMESS==TRUE DO IR_STOPM ( ) INTERRUPT ON 3
BAS (#INITMOV,0 )
;ENDFOLD (BASISTECH INI) ;FOLD USER INI
;ENDFOLD (USER INI) ;ENDFOLD (INI)
;--- Make your modifications here --- ;The Robot should go to the home outside to the tool storage cover
WAIT FOR In_ToolsHomeID==TRUE ;PLC->KUKA Activate the movement Tools Home ID Out_ToolsHomeID=TRUE ;KUKA->PLC ok it has been recived the command of movement
;In the meantime the PLC starts to open the cover of the storage
Goto_Tools_HomeID() ;The KUKA goes to the home outside the tool storage
;The tool storage cover is open
Out_ToolsHomeID=FALSE ;KUKA->PLC the movement have been done ToolsHomeID ;$OUT[9]=TRUE ;ToolStorageHomeReady
WAIT FOR In_ToolsHomeID==FALSE ;PLC->KUKA deactivate the command ToolsHomeID ;$OUT[9]=FALSE ;ToolStorageHomeReady
;PLC send a signal to the spindle to open the clamp WAIT FOR In_GotoToolHolder==TRUE ;PLC->KUKA Comand to go to the Holder position of the Tool
Out_ToolHolder=TRUE ;Moving2ToolStorage
;The KUKA goes to the position inside the storage to load the tool
Goto_Tools_HolderID()
;FOLD WAIT Time=0.5 sec;%{PE}%R 8.3.40,%MKUKATPBASIS,%CWAIT,%VWAIT,%P 3:0.5 WAIT SEC 0.5
;ENDFOLD
;PLC Check if tool is in the right position
Out_ToolHolder=FALSE ;KUKA->PLC the movement have been done ToolHolderID WAIT FOR In_GotoToolHolder==FALSE ;PLC->KUKA deactivate the command ToolsHomeID ;PLC opens the clamp of the spindle to load the tool
;FOLD WAIT Time=0.5 sec;%{PE}%R 8.3.40,%MKUKATPBASIS,%CWAIT,%VWAIT,%P 3:0.5 WAIT SEC 0.5
;ENDFOLD
WAIT FOR In_ToolsHomeID==TRUE ;PLC->KUKA invia attivazione per andare alla Tools Home ID
Out_ToolsHomeID=TRUE ;KUKA->PLC the command has been received ;KUKA goes the home outside the tool storage Goto_Tools_HomeID()
Out_ToolsHomeID=FALSE ;KUKA->PLC the movement have been done ToolsHomeID WAIT FOR In_ToolsHomeID==FALSE ;PLC->KUKA deactivate the command ToolsHomeID ;FOLD WAIT Time=0.5 sec;%{PE}%R 8.3.40,%MKUKATPBASIS,%CWAIT,%VWAIT,%P 3:0.5
WAIT SEC 0.5 ;ENDFOLD
;1) Close the storage and start processing END
3.3. PLC
3.3.1. Description of the PLC components
Figure 20. B&R Automation solutions.(From B&R Automation. 2018)[32]
To control the full CNC machine was chose a solution of an industrial PC. The common name of this controller is PLC (Programmable Logic Control), which can manage different typologies of systems from the servo motion, passing through the field devices, HMI interfaces and more components that belong to the industrial environment.
In specific was chosen a X20CP0484 industrial controller purchased from the B&R Automation company. This corporation has an smart solution because it has an integrated software (Automation Studio) that allows the development of the environment that contains tools for all phases of a project. Is possible configure and program almost all the components that belong to the plant as the controllers, drives, communications and visualization can all be configured in one environment. That reduces both integration time and maintenance costs.
Figure 21 is shown the X20CP0484 PLC principal characteristics. The CPUs X20 Compact-S family are both compact and powerful. The fanless, battery-free design of these CPUs means they are completely maintenance-free.
The X20CP0484 is equipped with an ARM Cortex A9-667 processor, 256 MB RAM and 2GB built-in flash drive. The FRAM for saving remanent variables has 64 kB available.
With POWERLINK, Ethernet, USB and RS232, the CPU offers ample communication options. A CAN interface is also available as an option. If the application requires additional interfaces, the CPU can be modularly expanded by one or two X20 interface slots. This allows the entire product range of X20 fieldbus interfaces to be used[33].
Figure 21. PLC X20CP0484.(From B&R Automation. 2018) [34]
This particular compact PLC allow the user to add all the additional I/Os needed for the whole control of the components that compose the plant, unlike the traditionals compact industrial PCs. In Figure 22 and 23 is possible to appreciate the final modular PLC with the adding of the different modules used for this project.
Figure 22. Cabinet I/O modules.(From P2C. 2018)
X20IF10E1-1 The interface module functions as a PROFINET RT controller (master). It can be operated in X20 CPUs or in the expandable X20BC1083 POWERLINK bus controller.
• PROFINET RT controller
• Integrated switch for efficient cabling
X20PS9600 The power supply module is used together with an X20 Compact-S CPU. It has a feed for the Compact-S CPU, X2X Link and the internal I/O power supply.
• Supply for Compact-S CPU, X2X Link and internal I/O power supply • Electrical isolation of supply and CPU / X2X Link power supply
• Redundancy of CPU / X2X Link supply possible by operating multiple supply modules simultaneously
• RS232 configurable as an online interface • CAN bus
X20SLX842 The module is equipped with SafeLOGIC functionality that allows it to safely execute applications designed in SafeDESIGNER.
• openSAFETY manager for up to 10 SafeNODEs
• Flexibly programmable using Automation Studio / SafeDESIGNER • Innovative management of safe machine options (SafeOPTION) • Parameter and configuration management
• 8 safe digital inputs, sink circuit • 4 pulse outputs
• Software input filter configurable for each channel
• 2 safe digital outputs, output type B with 50 mA, source circuit • Integrated output protection
X20DI4371 The module is equipped with 4 inputs for 3-wire connections. • 4 digital inputs
• Sink connection • 3-wire connections
• 4 counter inputs with 1 kHz counter frequency • 24 VDC and GND for sensor supply
• Software input filter can be conFigured for entire module
X20DO8322 The module is equipped with 8 outputs for 1-wire connections and designed for source output wiring.
• 8 digital outputs • Source connection • 1-wire connections
• Integrated output protection
X20AI2622 The module is equipped with 2 inputs with 13-bit (including sign) digital converter resolution. It is possible to select between the current and voltage signal using different terminals.
• 2 analog inputs
• Either current or voltage signal possible • 13-bit digital converter resolution
X20AO2622 The module is equipped with 2 outputs with 13-bit (including sign) digital converter resolution. It is possible to select between the current and voltage signal using different terminals.
• 2 analog outputs
• Either current or voltage signal possible • 13-bit digital converter resolution
X20BT9400 To make a connection from an X20 System to an X67 System, a bus transmitter is simply plugged into the end of the X20 block in order to connect the X2X Link cable. The X20BT9400 bus transmitter also provides the X2X supply voltage for the X67 System. The X67 system supply module that was previously required is no longer needed.
• Operation only on the slot to the far right
Table 7. Description of the I/O modules.(From Serecchia, G. 2018)
Figure 23. Cabinet-Storage I/O modules.(From P2C. 2018)
X20BR9300 X20 bus receiver, X2X Link, supply for X2X Link and internal I/O power supply • X2X Link bus receiver
• Feed for X2X Link and internal I/O supply • Electrical isolation of feed and X2X Link supply
• Redundancy of X2X Link supply possible by operating multiple supply modules simultaneously
• Operation only on the slot to the far left
X20DI8371 (x4) The module is equipped with eight inputs for 1-wire connections. The module is designed for sink input wiring.
• 8 digital inputs • Sink connection • 1-wire connections
• Software input filter can be conFigured for entire module
X20DO8232 X20 digital output module, 8 outputs, 12 VDC, 2 A, source, supply directly on module, 1-wire connections
• Rated voltage 12 VDC • Source connection • 1-wire connection
• Power feed integrated in the module • Integrated output protection
Table 8. Cabinet-Storage I/O modules.(From Serecchia, G. 2018)
Table 9. Cabinet-Storage I/O mapping variables.(From P2C. 2018)
3.3.2. The Supervisor
The Supervisor is the name given to the control software implemented for this specific CNC machine. It can be seen as a manager block that placed the plant in a state-flow procedure. Depending on the state where Supervisor is situated it can launch a specific external procedure (also named functions). The functions that can be called by the principal state allows controlling the robot, devices, spindle and plant procedures.
In this case Simulink was an optimal solution in one hand it permits to create a robust code and in the other was possible to code-generate (Converts some intermediate representation of source code into a form that can be readily executed by a machine) the program thanks to the Automatic Code Generation provided by the builders of the PLC. Automatic implementation of Simulink models in C/C++ Code, specially optimized for use in B&R target systems, offers the developer new possibilities for designing sophisticated simulation models and control structures that would otherwise be impossible or very time-intensive to implement.
The biggest advantage of Automatic Code Generation affects those developers who already use MATLAB and Simulink for simulation and solutions design and to developers who used to tediously rework implemented structures in a language supported by Automation Studio in the past. In the procedures listed below, the Automatic Code Generation tool provided by B&R represents an innovation with end less possibilities that help to productively reform the development of control systems. The basic principle is simple: The module created in Simulink is automatically translated using Simulink Coder or Embedded Coder (optional) into the optimal language for the B&R target system, guaranteeing the maximum performance of the generated source code. Seamless integration into an Automation Studio project makes the development process perfect.
The elimination of extensive reengineering in Automation Studio allows simple transfer of complex and sophisticated Simulink models to the PLC (Hardware-in-the-Loop). Closed-loop controllers can also be easily tested and optimized on the target system without requiring the user to adjust large amounts of code and run the risk of creating coding errors (On-Target Rapid Prototyping).[35]
Figure 24. Workflows of the Automatic Code Generation.(From B&R Automation. 2018)[35]
On-Target Rapid prototyping
Automatic Code Generation makes it possible to quickly and easily transform sophisticated Simulink based control systems into source code and integrate them into an Automation Studio project.
Hardware-in-the-Loop
Every modification of the closed-loop controller bears the risk of damaging the controlled system during commissioning. ‘Hardware-in-the-Loop’ is the key word that stands for simple transfer of sophisticated system models developed in Simulink to a B&R target system. The prepared PLC assumes the role of the actual system for the duration of the first function test. This allows easy and safe testing of new controller concepts without risking the damage of costly machine parts. In some cases the controller and system simulation can even run on the same target system. [37]
In Figure 25 is present a symbolic graph of the Supervisor specially achieve for the plant, as mention before there is a principal block that manege the different procedures
Figure 25. Supervisor diagram with its functions.(From Serecchia, G. 2018)
3.3.2.1. Bus object
The Supervisor use a massive number of variables that are sent/received from the PLC to the other systems of the plant. So it was important to design an strategy to simplify the signals decoding in the process of programming, testing and diagnostic.
To design an efficient method was use the bus object feature provision by MATLAB®. A bus object specifies only the architectural properties of a bus, as distinct from the values of the signals it contains. For example, a bus object can specify the number of elements in a bus, the order of those elements, whether and how elements are nested, and the data types of constituent signals; but not the signal values. A bus object is analogous to a structure definition in C: it defines the members of the bus but does not create a bus. Another way of thinking of a bus object is that it is similar to a cable connector. The connector defines all the pins and their configuration and controls what types of wires can be connected to it. Similarly, a bus object defines the configuration and properties of the signals that the associated bus must have.[38]
Input bus objects
• HMII.: Input signals from the Human Machine-man Interface(HMI).
• DI.: Input signals from the digital inputs of the different sensors placed in the plant.
• KIcom.: Input signals from the KUKA robot specific to the communication variables.
• KI.: Input signals from the KUKA robot specific to the machining variables.
• InvI.: Input signals from the Inverter controller.
• SpdI.: Input signals from the spindle CANopen communication bus.
Output bus objects
• HMIQ.: Output signals to the Human Machine-man Interface(HMI).
• DQ.: Output signals to the the different sensors placed in the plant.
• KQcom.: Output signals to the KUKA robot specific to the communication variables.
• KQ.: Output signals to the KUKA robot specific to the machining variables.
Figure 26. Bus object, represent the I/O variables that travel from one system to another in order to propagate the variables information.(From Serecchia, G. 2018)
3.3.2.2. Robot functions
In this section is possible to have a generic overview about the function implemented to activate the robot procedures.
The first important functions implemented were the communication procedures, they aim to stand-up the initial hand-shake between the controller (PLC) and the robot to allow then exchange of information. Once this functions has been successful run the PLC can communicate with the robot controller via the “Automatic External” interface and activate various robot processes. Similarly, the robot controller can send information about operating states and fault signals to the host computer.
SYS HMII. DI. KIcom. KI. InvI. SpdI. HMIQ. DQ. KQcom. KQ. InvQ.
Figure 27. Automatic system start and normal operation with program number acknowledgement by means of PGNO_VALID. (From KUKA. 2005)[39]
The communication procedure was divided in two sub-functions, the first one called just once starting the machine (left part of the red dashed line); the second one run each time was necessary to activate a PGNO number program apart from the communication procedure (right part of the red dashed line). The activation of this functions allow the system to work in autonomy calling automatic process without the intervention of the operator just as the goal of this project. Consider Figure 27 it can be acknowledge that the communication functions consist of an exchange of variables values between the PLC and the KRC robot controller.
Besides, there were other procedures implemented to upgrade this CNC machine, among them is possible to find the Tool setter function, that improve machine accuracy of CNC machine tools. Allowing automated operation with some benefits as significant time savings with reduced machine downtime; Accurate tool length and diameter measurement; Automatic tool offset calculation and correction; Elimination of manual setting errors; In-cycle tool breakage detection. It consists of two functions, the initial one makes the robot reach the position of the tool setter sensor, then starting to move the robot from the actual position to a point near to the sensor, afterward the robot goes to two new points, the first just in front of the sensor (position that does not touch the sensor) and the second is the point where the tool active the sensor, so there is contact between the sensor and the tool. The velocity of movement among the last two point is low in order that the tool does not break the sensor. The second function programmed for this scope was the acquisition of the measure once the tool was over the sensor. The sensor had a precision of 1μm, so it was decided to do 3 repeat cycles of this two functions, as a result, obtain three measures that allow calculating the average of them, in order to have a valid approximate tool length value. In Figure 29 is shown the tool setter functions with its inputs and outputs buses objects.
Moreover was set up a procedure to move the robot from a random point of the work-space to the home park position, a secure position where the robot permits the operator get inside the work area without risks.
Figure 30. GOTO_HOME functions variable exchange. (From Serecchia, G. 2018)
Figure 31. symbolic GOTO_HOME function. (From Serecchia, G. 2018)
The last function robot codify was the CAM function, in this block first the system launch a procedure to read the “Directory Loader” (folder with inside 1-255 files) where are located all the PGNOs codes. Before to launch the specific g-code (with the movement of the robot and velocity of the spindle) request by the operator the PLC verify that the tool and head loaded on the robot are the same as the require by the specific PGNO that will be running. If the presents and requires devices not match, the function provide to change them automatically without the intervention of the operator. Once the CNC machine is ready to start, the principal controller gives the command to the robot to process the movement inside the PGNO file and give a velocity reference to the spindle to proceeding with the milling. When the robot program is finished the PLC send the signal to the spindle to stop and the function continue to read the next PGNO file launch by the operator or in the absence it stop the CNC machine.
3.3.2.3. Device management functions
The follow functions aim to manage the change of tool and head whenever is a request. The CNC machine includes a storage box where are placed 20 tools for the different milling process and 2 heads, a spindle and a sander. Them can be replaced or load to the robot through two strategies, the first one is a manual procedure, the operator can choose any tool/head of those available in the HMI interface (Storage page) to be load or unload if there is already a combination of devices on the TCP; the second one is an automatic procedure handle by the CAM function that has the credential to call other functions as the tool/ head load and unload. Is relevant clarify: (1) A tool can only be load if there is before a head load on the robot TCP; (2) The only head that can load tools is the spindle, the sander does not expects to load tools.
The Functions TOOL_LOAD(), TOOL_UNLOAD(), HEAD_LOAD() and HEAD_UNLOAD() create a timing change of signals between the PLC that manage all the process, the robot that do the movement to go inside the storage to load or unload the devices, the storage that verify the state of the tool/head and handle the open and close of the cover to make possible access to the equipment and the pressure valves to open and close the spindle and TCP clamp. In Figure 32, 34, 36 and 38 are describe all the variables exchange between the CNC machine systems.
Figure 33. symbolic HEAD_LOAD function. (From Serecchia, G. 2018)
Figure 34. HEAD_UNLOAD functions, variable exchange cycle. (From Serecchia, G. 2018)
Figure 36. TOOL_LOAD functions, variable exchange cycle. (From Serecchia, G. 2018)
Figure 37. symbolic TOOL_LOAD function. (From Serecchia, G. 2018)
Figure 39. symbolic TOOL_LOAD function. (From Serecchia, G. 2018)
Another function important implemented on the Supervisor was the “N_ParkingCheck”, this code is a cyclic reading of the devices sensors placed on the storage to understand the presence or not of the tools/heads. This function confront the values of the 22 capacitive sensors (20 tools plus 2 heads) and the values introduce by the operator that placed a device in a maintenance state, giving a color to some digital leds associated to the state of the device. There can be four states for each device as describe here:
• Tool/Head is present in the storage - GREEN LED color • Tool/Head is on maintenance - YELLOW LED color • Tool/Head is loaded on the robot - BLUE LED color • Tool/Head has a check problem - RED LED color
A check problem can be verify when a device is not in the storage and is not reported as in maintenance or if both are verified.
3.3.2.4. Spindle functions
The spindle functions are linked to the operation of the spindle and the sander. As mention above the heads are connected to an Inverter that control the rotation velocity of them. Having a exchange of commands between the PLC and the Inverter to obtain final and desire control of the mechanical system.
There were programmed four spindle functions:
• SPINDLE_START( ) : This functions start the communication between the PLC and the Inverter, so the PLC send some commands to active the power on, the enable and the current on of the inverter.
Figure 40. symbolic SPINDLE_START function. (From Serecchia, G. 2018)
• SPINDLE_STOP( ) : These functions stop the communication between the PLC and the Inverter, so the PLC send some commands to deactivate the “power on”, the “enable” and the “current on” of the inverter.
• SPINDLE_RUNNING( ) : Once the function SPINDLE_START( ) was launch is possible to run the spindle/sander giving it a velocity reference. These functions actives the rotation of the load head from an automatically reference signal received from the CAM function or simply a manual operator command from the HMI interface.
• SPINDLE_WARMUP( ) : At the time of the first daily start-up, it is necessary to let the electric-spindle perform a short preheating cycle, to allow the bearings to gradually reach a uniform operating temperature, and thus obtain uniform run-out expansion, and preload and stiffness. It is absolutely necessary to respect the following preheating cycle, without making any work:
- 50% of the maximum rated speed for 2 minutes. Use a tool holder with maximum speed ≥ maximum nameplate speed;
- 75% of the maximum rated speed for 2 minutes. Use a tool holder with maximum speed ≥ maximum nameplate speed;
- 100% of the maximum rated speed for 1 minute. Use a tool holder with maximum speed ≥ maximum nameplate speed.
The pre-warming up-cycle must also be performed each time the machine remains inactive for a time sufficient to cool the electro-spindle to room temperature. Only in the case of initial start-up after storage or downtime of more than four months, precede the preheating cycle from a preliminary phase of 2 minutes at 5000 rpm. In Figure 38 is shown the variables exchange chart of this function.
Figure 42. symbolic SPINDLE_WARMUP function. (From Serecchia, G. 2018)
Figure 43. SPINDLE_WARMUP functions, variable exchange cycle. (From Serecchia, G. 2018)
• SPINDLE_MONITOR( ) : This is a cyclic functions that is always running when the spindle is load on the robot. It verify the regular working of the spindle, reading constantly the error messages of the P75 electrical-board and processing them depending of the level of risk. In table 10 are some of the variable interpret by the PLC. Depending of the error message the PLC will take a decision of continue the milling process or just abort it.
Table 10. Spindle electric board, CANopen error/Alarm messages. (From Serecchia, G. 2018)
Figure 44. symbolic SPINDLE_MONITOR function. (From Serecchia, G. 2018)
3.3.2.5. Plant functions
Some other features that permit to control the whole plant are the lubrication functions. This procedure allows the activation of the lubrication pumps placed on each slider that
Figure 46. symbolic PUMP1_LUBRICATION function. (From Serecchia, G. 2018)
Some other functions used for the plant management were VALVES() that manage the seven pressure valves that allows open TCP clamp to unload the spindle, close the TCP clamp to load spindle or sander, open the spindle clamp to unload a tool, close the spindle clamp to load a tool, Funnel, Sanding load and unload sander; ADMIN() a function that allows the operator to access to the full features and commands of the HMI interface; WORKING_TIME() this last function gives some information about the working time by the devices.
3.3.2.6. Spindle velocity control
In this part is described the strategy used to control the velocity of the spindle. It was implemented a PI (Proportional-Integral) control for this scope. It is a control loop feedback mechanism widely used in industrial control systems and a variety of other applications requiring continuously modulated control.
The Setpoint is the value that we want the process in this case, is the velocity reference give it by the CAM function or manually by the operator. The PI controller looks at the setpoint and compares it with the current value of the velocity, this process variable is read by the P75 electric board placed on the spindle and connected to the CANopen bus that transmit the information to the PLC. If the setpoint and the process variable are the same then the controller will set its output to zero because the desire and the actual
the setpoint respectively. Figure 47 is possible to appreciate the feedback loop specific for this application.
Figure 47. Feedback diagram of the spindle velocity control. (From Hogenson, J.) [41]
The PI controller is structure by two contributes the first one a proportional part 𝑆𝑃𝐺 ∗ 𝑒(𝑡) that is multiplied by the error between the desire and actual velocity; the second one is the integral part 𝑆𝐼𝑇 ∗ !"! 𝑒(𝑡), in this case the error is integrated. So the full controller expression is the sum of the two above values. Figure 48 are shown some graphics of how affects 𝑆𝐼𝑇 and 𝑆𝑃𝐺 the tuning values with the response. Normally this configuration is used for applications requiring flexibility and stability.
• [Speed proportional gain] (SPG) affects excessive speed.
• [Speed Integral Time] (SIT) affects the passband and response time.
Figure 48. Response graphs of the PI control. (From Serecchia, G. 2018)
Velocity reference
3.4 HMI Interface
The supervision is the software created for controlling all the plant is equipped with a dedicated man-machine interface that allows the management and monitoring of production and process phases through an HMI interface that makes easy the operator control; this interface is divided into the following sections to which the corresponding pages are associated:
- Home
This section represents the main page of the man-machine interface and here the main information of the system is displayed.
- Maintenance
This section is dedicated to the maintenance of the heads and tools in the warehouse; this check is performed independently. The appropriate LED indicates the correct check of the tool that can be removed from the warehouse. This option must be used when there are empty tool-holders or head-holders in the magazine for the relative component not available.
- Storage
This section is intended for the selection of tools and robot heads to be loaded on the anthropomorphic robot, allowing to view in real time the status of the tools and heads (present, non-present, loaded on the robot) and the status of the magazine cover ( open, closed) through the use of appropriate proximity sensors.
- Electro-spindle
This section is dedicated to monitoring the component's operating parameters.
- Alarms
This section is dedicated to monitoring current alarms, acceptance of the same, with related alarms history.
- States
In this part of the interface is possible monitoring and controlling some of the variables associated to the communication between the robot and the PLC, besides there are button to reset the procedures and reset the stateflow machine.
- CAM Program
The CAM activation is the most important part, from here is possible to start the g-code associated to a number program obtained in a offline procedure.
- KUKA Info
In This section is dedicated monitoring all the position of the robot and its external axes, focusing on the position of the TCP and its velocity.
3.4.1 Introduction to the operating modes HMI
The plant can operate separately in three operating modes: to. (a) automatic operation (b). manual operation.
3.4.1.1 Automatic operation
The automatic operating cycle is the normal operating mode of the system and the operator does not have to take care of carrying out operations regarding the advancement. It will be the task of the supervision system. The system management software will execute them to bring to the destination the movements set on the supervisor and the steps from one station to another.
3.4.1.2 Manual operation
The manual operating cycle is the mode where the operator has the full control of the plant. It will be possible to run, stop or wam-up the spindle, move the robot, activate the different digital output as the lubrication pumps. So is possible to have the full command of the plant.
3.4.2 HMI Objective
The main objective of the HMI is to translate complex process variables into information that can be immediately used to be converted into actions, such as being able to read the revolutions per minute that a spindle performs over time or even the ignition of an entire industrial automation system through a single digital key. The management systems and the human-machine interface must allow the visualization of real-time operating information of sensors and actuators allows system control.
The process graphics allow to assign a context and a meaning to the elements of the plant, from the status of valves and motors, to the tank levels and to the other process parameters. HMI systems therefore allow to obtain an in-depth understanding of processes, favoring their control and optimization through the regulation of production and process targets.
3.4.3 Software functionality.
3.4.3.1 Graphic interface
Industrial equipment and machines require integrated automation systems. One of the main difficulties of an automation system is that of "talking" to each other different hardware components, ensuring the timing dictated by the project itself. The centralized acquisition of data coming from every module of a production line allows a complete control of online performances. The traceability of material flows allows to monitor at any moment and in a transparent way each completed production phase.
The control and supervision software allows both the correct interaction of the robot's actuation system and the completion of the working functions of the composite product and the remote monitoring and supervision of productivity, hours of work, control charts. The plant is certified in compliance with the dictates of "Industry 4.0". The system allows the milling and sanding of large surfaces, using robots equipped with anthropomorphic arms with ample freedom of movement. The system management software allows complete automation of the whole processing, thanks to the availability of different tools and robots heads in completely sensorized storage.
This section describes the graphical interface that allows the operator and also the administrator to interact with the system, navigating through the appropriate pages listed below.
3.5 HMI Interface Characteristic.
3.5.1 Home
Figure 50. Home page. (From Serecchia, G. 2018)
3.5.1.1 Structure
Section 1
Section 2
Figure 52. Some variables show the spindle status a) velocity of the spindle in rpm; b) alarm temperature of the engine or on the electric board connected to the CANopen line. (From Serecchia, G. 2018)
Section 3
Figure 53. Operative mode three options a) Operator mode where in not possible to access to the control page; b) Administrator 1 mode where in possible to have access to the whole system and variables; c) Administrator 2 is the same as the Administration 1 with the different that is not possible have access to
the pressure valves that control the open and close clamp. (From Serecchia, G. 2018)
Section 4
Section 5
Figure 55. Emergency variables, is this part is define a) Safety program running: the safety module has its own program that periodically reads to ensure the good work of the plant, b) Emergency stop: this part is link to the four security button placed around the plant, c) Emergency acknowledge: refer to the operator acknowledge to proceed to the machining. (from Serecchia, G. 2018)
EXECUTION OF THE SAFETY PROGRAM: the LED with green indicator light is for the operation of the internal program of the module (insert photo module yellow).
PRESSED MUSHROOM: the green LED lights up the physical contact with the various emergency buttons.
RESTORATION BUTTON: confirmation by the expert operator following an emergency.
CONFIRMATION BUTTON: to restore the system, after having released the emergency functions. This function must be performed after the expert operator inspects the damage or errors presented.
ACTIVE EMERGENCY SIGNAL: Red LED
Figure 57. Acknowledge button, is required to press it to start the machining and to enable the supervisor program to start. (From Serecchia, G. 2018)
Figure 58.Overview of the control keyboard, a) Acknowledge button: Start o continue the supervisor after a emergency problem or just starting the machine; b) Continue button: Continue the CAM process
and spindle running after an emergency error; c) Stop button: The robot and the spindle are arrest because and error; d) Cancel button: Is possible to cancel a running CAM program; e) EM_ACK button:
there is a problem running a program in the robot requested by the PLC . (From Serecchia, G. 2018)
CONFIRMATION BUTTON: to restore the system, after having released the emergency functions. This function must be performed after the expert operator inspects the damage or errors presented.
CONTINUE: Is a digital Input. It allows to continue the task of the robot and the spindle after an emergency situation. The operator must press the continue button to continue the machining. STOP: Is a digital output .when is red means that the plant is Stop .
Figure 59. Emergency buttons placed on the longitudinal sliders. (From Serecchia, G. 2018)
3.5.2 Maintenance
Figure 61. Maintenance page. (From Serecchia, G. 2018)
This section concerns the status of tools and heads in the storage. Each "Tool xx" tool is associated with a virtual led indicator that indicates the status of the tool in the storage. Is a semi-automatic page because is needed that the operator check the tools/heads that are in maintenance to avoid problems doing the cyclic verification of the capacitive sensor state placed on each location of the twenty-two devices.
In particular each device can be in different states:
• Tool/Head present in the storage - GREEN LED color • Tool/Head is on maintenance - YELLOW LED color • Tool/Head is loaded on the robot - BLUE LED color • Tool/Head has a check problem - RED LED color
Similarly, this section allows to manage the status of the heads in the storage; as for the tools, each head is associated with a led indicator that indicates the status of the head in the storage, with the same color convention. When the operator manually extracts a tool
or a head from the magazine to perform maintenance, is necessary to indicate the check box to avoid problems in the cyclic reading
All the management of the presence or absence of the tools and heads in the corresponding positions in the storage is based on the information coming from the relative proximity sensors installed on the tooling forks and head flanges.
3.5.3 Storage
Figure 62. Storage page. (From Serecchia, G. 2018)
This section is dedicated to the selection of the tool and the head to be loaded on the robot: through a special "radio button", is a mutually exclusive single-choice manner, it is possible for the operator to select one of the tools or heads available in the storage to be load. In fact, the tools that are not in the storage are not selectable and its own radio button is disabled and the names are block(white lettering). For each tool head and is associated a LED indicator whose color identifies its own status:
Another point to highlight is the tool or head, the page blocks the radio buttons until the tool is completely loaded or the robot is loaded, once the loading is complete it is unlocked, so you can choose a new tool or new head from to load. It is possible to monitor the status of the tools and then monitor if it has been loaded on the robot, if it is under maintenance or if it is inside the storage thanks to the LEDs that change color according to the progress. In addition, on this page of the HMI Man-Machine interface the status of the storage’s cover is displayed, both for the heads and for the tools, defined as follows:
• Tool/Head cover is open – YELLOW LED color • Tool/Head cover is in the middle – GREEN LED color • Tool/Head cover is close – BLACK LED color
• Tool/Head cover is in a error situation – RED LED color
3.5.4 Electro-spindle
Figure 63. Spindle page. (From Serecchia, G. 2018)
This section is dedicated to monitoring the operation of the HSD electro-spindle. The electro-spindle communicates with the PLC via CANopen communication protocol and on this page the most relevant information is displayed for material processing and for
correct operation of the system. The HSD supplier of the fan cooling electro-spindle ES951 uses pairs of high-precision angular contact bearings, preloaded and lubricated for high speed processing.
Figure 64. Spindle HSD ES951, a) Spindle mounted on the robot’s TCP, b) Spindle model. (From Serecchia, G. 2018)
More specifically, the information that the electric spindle sends to the PLC are of two types: Boolean information TRUE / FALSE or numerical information (such as for example the rotation speed).
Electro-spindle alarms. Any deviation from the ideal operating conditions of the device is defined as an anomaly. Depending on the possible consequences on any work in progress, the anomalies are classified into three basic groups:
• Severe anomalies (FAILURES): The anomalies of this type indicate situations that endanger the safety of the machine: they require immediate shutdown.
• Negligible anomalies (NOTIFICATIONS): These anomalies indicate conditions that have no effect on the work activity, which can continue without problems. There is no need to stop the machine.
Every anomaly, to whatever group it belongs to, is notified by the P75 communication board mounted on the electro-spindle by means of an emergency telegram based on CANopen communication protocol, indicating the code associated to the anomaly. In addition to each anomaly, a single bit is associated with the anomaly mask. CANopen object (Index 3001h, SubIndex 0). The table below lists the anomalies, in the order in which they appear in the fault mask, specifying, for each, the associated CANopen emergency code and the group to which it belongs.
Table 11. Spindle electric board, CANopen error messages. (From Serecchia, G. 2018)
ERR_CRC is a notification, as it becomes serious only if both the backup parameters and the machine parameters are damaged, but in this case the calibration values are reset, and then the ERR_OUTOFBOUNDS fault occurs, which is a fault (serious fault). ERR_PARAMETERS is also a notification, but the situation causes the serious ERR_OUTOFBOUNDS anomaly. Not all the anomalies reported by CANopen emergency messages are managed in the same way; only faults cause the machine to
stop immediately. The alarms allow instead of completing the work in progress before stopping the machine, while the notifications are only informative value.
Table 12. Spindle electric board, CANopen error/Alarm messages. (From Serecchia, G. 2018)
An example: if the CANopen emergency message arrives with the code associated with AL_STATISTICS_WRITING, that is writing error in EEPROM of the machining statistics, the machine obviously should not be stopped, not even at the end of the work in progress, because this situation does not influence the machining. It could, at worst, indicate problems in the EEPROM area dedicated to statistics.
3.5.4.1 Technical management of Electro-Spindle
Table 13. Index 2200h of the CANopen communication it indicates the temperature value of the electric board that manage the exchange of data inside and outside the Spindle system. (from Serecchia, G. 2018)
Table 14. Index 2208h of the CANopen communication it indicates the temperature value of spindle stator. (From Serecchia, G. 2018)
3.5.4.2 Aims of the CanOpen
Figure 65. Connection pins for the CANopen. (From HSD. 2016)[42]
The use of CANopen has the following objectives:
• Create a clear and concise specification to facilitate implementation and maintenance. • Use as far as possible existing international standards.
• Use the smallest possible number of communication objects - communication objects (CAN identifiers).
• Being able to cover the wide range of devices used in machine automation. • Ensure reliable and accurate network behavior.
With these objectives, CANopen was developed using only a small number of communication functions machine automation, resulting in reduced demand for processors and memories.
3.5.4.3 Setting Dipswitch for field-bus CANopen
Figure 66. Dipswitch spindle configuration. (From HSD. 2016)[43]
The configuration of the Dipswitch when the component is supplied is: Position 1: ON; Position 2 ÷ 8 : OFF
The default communication speed is 500 Kbits / sec, if not aligned with that of the numerical control, it is necessary to follow the baudrate setting procedure described below. If the electronic card is not powered, the Dipswitch must be set according to the table below, provided that the Dipswitches 4 and 5 must be set to "OFF"and Dipswitch 6 must be set to "ON":
Table 15.Dipswitch baudrate configuration. (From HSD. 2016)[44]
Logical address of the electro-spindle and line termination of the CANopen bus. The first 5 Dipswitches identify the address, the Dipswitch 6 must be "OFF" and the Dipswitch 7 and 8 identify the termination. Switches 1 to 5 set the CANopen address of the electro-spindle; in particular, switch # 5 corresponds to the most significant address bit A4, and switch # 1 corresponds to the least significant address A0. All 32 combinations between 0 and 31 are allowed. "Transcribe" the address in binary form on
the switches n ° 5 to n ° 1, or equivalently decompose the address as the sum of the powers of 2 (see the table and 'example described later).
Two devices on the same line field-bus may not have the same address.
Change the Dipswitch configuration only for non-powered card.
Turn on the card and wait for the LED to flash; at this point it is possible to proceed with the reconfiguration of the desired addressing. To reset the CANopen card to the factory default values, with the electronic card not powered, set the Dipswitch 6, 5, 1 to "ON". At this point the power adapter, and then turn it off.
Figure 67.Dipswitch binary port configuration. (From HSD. 2016)[45]
Example: the decimal address "1 3" corresponds to the track 01101 and is set to the Dipswitch, as follows:
3.5.5 CONTROL
Figure 69. Control page. (From Serecchia, G. 2018)
This control section is only accessible through the credentials of "System Administrator" as it is possible to perform specific functions manually which must be done only by an expert user.
The operator, has an important role both in the planning of the mission and during its execution, the operator must command, check analyze the information coming from the sensors, make sure that the implemented automation "works" and, if it does not work, to intervene.
This allows the operator use the machine in total safety and to perform service diagnostics in an easy and efficient way. In particular, in this page of the Human-Machine Interface (HMI) the operator can act directly on the robot by changing its position and on the electro-spindle.
As is shown in the next Figures there is an Exchange of variables between the different systems of the plant to process a function each time is activate a button of this page. In this case are report just to of the temporary buttons.
Figure 70. Go to home function exchange of variables between the systems. (From Serecchia, G. 2018)
Figure 71. Warm-up function exchange of variables between the systems. (From Serecchia, G. 2018)
The HSD supplier of the electro-spindle uses high precision angular contact bearings, pre-loaded and lubricated for life with special high-speed grease.
Figure 72. Valve control chart, (1) Open head to unload the spindle; (2) Close head to load spindle or sander; (3) Open clamp to unload a tool; (4) Close clamp to load a tool; (5) Funnel; (6) Sanding load and
unload sander; (7) Valve is a free valve available for updates. (From Serecchia, G. 2018)
Figure 73. Lubrication pumps activations, a) Pump 1 is the one placed on the transversal slider; b) Pump 2 are the two pumps placed on the longitudinally sliders. (From Serecchia, G. 2018)
3.5.5.1 Security connections
Figure 74. Security connections. (From P2C, 2018)
The B&R security system, consisting of the X20 SafeIO, SafeLogic and SafeDESIGNER toolset from Automation Studio, is enhanced with the addition of ACOPOS multi Inverter units with Integrated Safety Technology (SafeMC).
This makes it possible to create highly effective application solutions with integrated security technology. The approach adopted is based on the use of OpenSAFETY across the board. This system allows the integrated safety functions such as speed limitation (SLS) to be activated directly on the network. The information is acquired from the respective sources via safe digital inputs and outputs, and then distributed to the respective sensors and actuators, in this case the drives with integrated safety functions, via a safe CPU: the SafeLOGIC controller.
The connection via POWERLINK guarantees the best possible communications between the SafeLOGIC controllers and the standard ones used to create programs not associated with security.
3.5.6 ALARM
Figure 75. Alarm page, two charts, a) Current alarms; b) History alarms. (From Serecchia, G. 2018)
3.5.7 STATUS OF THE SYSTEM
Figure 76. State page, two charts, a) Current alarms; b) History alarms. (From Serecchia, G. 2018)
In this section are specified all the communication variable used by the Robot and the PLC to start, stop and run a specific robot program(PGNO) previously programmed on the KRC4 using WorkVisual.
Figure 77. State page, two charts, a) KIcom: KUKA input communication bus(PGNO_REQ, STOPMESS, APPL_RUN, PERI_RDY, ALARM_STOP, USER_SAF, I_O_ACTCONF, PRO_ACT);
