Mobile Arm Simulation 3D

Transcription

1 Operating Manual Mobile Arm Simulation 3D January 2012, Heilbronn MAS3D-OperatingManual Neobotix GmbH all rights reserved 1 of 19

2 Contents 1 Introduction Contents of this document Format of this document Overview System structure Components Glossary Installing the host computer Windows operating system Linux operating system Setting up the network First steps Network connections Using the mobile platform Using the manipulator Application specific programming The Python-Interpreter Other external Clients Legal notes...19 MAS3D-OperatingManual Neobotix GmbH all rights reserved 2 of 19

3 1 Introduction 1.1 Contents of this document This operating manual explains how to use the Neobotix graphical user interface for mobile manipulators. There are two possibilities to use the software: real-world and simulation mode. In simulation mode no hardware is required. The original platform controller software is running on the host-computer and simulates all sensor signals. This document contains information on: The interaction of the Neobotix software modules How to set up the control computer and the network Easy and basic tests of the system operation Basic functions and features of the system Important information for setting up customer specific applications All these points and most of the GUI's features are described in detail. So for most customers and applications this document should provide all the information necessary to set up the mobile manipulator. If any further information is needed, for example when doing research or installing very specialised applications, please refer to the Neobotix ArmCtrl Programmer's Guide, the PlatformCtrl Programmer's Guide or contact Neobotix. 1.2 Format of this document Once the hardware has been set up according to the operating manual or the technical description, the platform will operate very safely. Due to the complexity and capability of the system there will still remain the possibility for collisions and other damages. Unfortunately these can not be avoided without significantly reducing the operability. Therefore the system must only be set up, tested and operated by personnel that has been trained accordingly. Highest safety can only be achieved if all parameters are set correctly! To help setting up a safe and convenient application the following two icons mark important paragraphs: The warning triangle marks paragraphs that concern the danger of injuries, damages or both. Please make sure to read these paragraphs very carefully! The light bulb marks paragraphs which deal with common problems, misunderstandings and errors and is meant to be a help in troubleshooting. MAS3D-OperatingManual Neobotix GmbH all rights reserved 3 of 19

4 2 Overview 2.1 System structure The overall system is made up from a large number of components which might be customised according to the application's requirements. The following diagram shows the basic interaction of these components in a common set-up. Figure 1: Structure diagram All Neobotix software modules communicate via sockets. Application specific clients can optionally be connected using Modbus communication. 2.2 Components Mobile platform In many applications a mobile platform from Neobotix is used as base for the manipulator. This allows the arm as well as other load to be autonomously positioned in the workspace. Using Neobotix hardware is not mandatory. The manipulator can also be mounted on other platforms, on a linear axis, on a rail system or a fixed base. In these cases the motion control of the arm's base might need to be realised by a third party system. Manipulator and gripper The motion control module ArmCtrl can be used to directly control robot arms, modules and grippers from Schunk GmbH, e.g. the LWA light weight arm. Almost every other hardware can be controlled if motor amplifiers from Elmo Motion Control are used. Additional hardware The application's requirements specify the additional hardware that is used in combination with the mobile robot. Interaction between the robot and this hardware can either be direct, e. g. via digital interfaces or radio signals, or indirect by using a client program. MAS3D-OperatingManual Neobotix GmbH all rights reserved 4 of 19

5 PlatformCtrl This software module implements the control of the mobile platform and features localisation, path planning, collision avoidance and several hardware related functions. It has to be executed on the platform's on-board computer. PlatformCtrl does not provide a graphical user interface on itself. PlatformCtrlGUI This graphical user interface is the main tool for set-up and configuration of PlatformCtrl and the mobile platform. It provides tools to easily create maps of the environment as wells as roadmaps which define target stations and paths. ArmCtrl Motion control of the manipulator arm and additional axes like grippers is implemented in this module. It has to be executed in a soft real-time environment and, like PlatformCtrl, does not contain a user interface. Mobile Arm Simulation 3D This is the main user interface for controlling the manipulator or combined robot systems. MAS3D can communicate with both ArmCtrl and PlatformCtrl at the same time and furthermore can be used to integrate a Python script interpreter for easy programming of the robot. Application specific client For most applications a high-level control program is required. This program needs to communicate with all other components and modules and coordinates the overall process. Simple applications can be realised by using a Python script, while more complex systems might require more sophisticated programs. Due to the open protocol used by the Neobotix modules implementing a client is not difficult. Other components If necessary many third party components, from remote emergency stop systems to image processing, to top-level production control systems, can be connected to the mobile manipulator system. The available interfaces are not limited to those mentioned in this document. If requested, Neobotix can provide other interfaces and protocols as well. 2.3 Glossary Kinematics Kinematics describe how the axes (also referred to as degrees of freedom) are connected geometrically and mechanically. Depending on alignment and offset, the same number of axes can result in completely different capabilities and motion possibilities of the robot arms. Therefore it is very important not only to use the kinematics that matches an arm's hardware but also set calibrate the arm properly and to set all parameters correctly. Even minor discrepancies between the real-world robot and the mathematical model can cause significant inaccuracies and problems. Nevertheless, these discrepancies will not affect the repeat accuracy of the system. Tool centre point The tool centre point (TCP) is a virtual point in or near the used tool. This point is used when creating trajectories in certain motion modes. MAS3D-OperatingManual Neobotix GmbH all rights reserved 5 of 19

6 The TCP is located in the centre of the robot's hand flange by default. It will often be better to shift the TCP according to the tool to make programming easier. Rotations can then, for example, be performed around an axis of the gripped object. Workspace The workspace of a robot arm differs significantly from the workspace of a human arm, even in cases where both have the same degrees of freedom and similar kinematics. Poses which can easily be reached by a human arm are often impossible to reach for a robot, due to mechanical constraints, self-collision avoidance and lack of flexibility. Beside that, the fact that a robot's base is fixed and can not perform any kind of supporting movement, is often forgotten. The workspace can be divided into different areas: The overall workspace contains the volume which the TCP can reach in arbitrary orientation. The number of possible orientations decreases while moving further away from the robot's base until only one orientation (arm fully stretched) is reachable. A similar effect reduces the possibilities when moving too close towards the robot itself. The usable workspace is defined by the volume in which at least all orientation required for the given task can be reached. This volume will always lie within the overall workspace and will in most cases also be considerably smaller. When leaving the usable workspace, it might happen that position and / or orientation of the TCP differ from the commanded values due to the kinematics' constraints. The area in which all theoretical orientations are actually available is the smallest workspace and has no importance for most applications. Singularities Positions of the arm in which even small movements of the TCP cause very big or very fast movements of the axes are called singularities. This effect can occur when the whole arm or only the wrist is straight. Passing such positions will often result in an error because some of the axis can not reach the extreme speeds that would be necessary to follow the calculated trajectory. Accuracy The repeat accuracy for reaching a given position is generally independent from the kinematics, the calibration and the parameters and is only affected by the quality of the gear boxes, the motors and the encoders. This accuracy is usually much better than one millimetre. The accuracy with which positions and trajectories are reached in a given coordinate system depends very much on the other variables. The better measurements, calibration and orientation to the surrounding are, the better and more accurate the robot's work relative to a coordinate system will be. Single axis motion ArmCtrl can move a single axis independently from all others, thus allowing to perform quick and simple tests. This function can also be used to conveniently determine the limits of each axis and to carefully move the arm out of critical situations. Point-to-Point motion In a point-to-point motion (PTP) all axes are moving synchronously from their respective start position to the target position. The parameters of this motion mode can be set very freely and will affect all drives. MAS3D-OperatingManual Neobotix GmbH all rights reserved 6 of 19

7 Because this motion mode is based only on the velocities of the drives, the resulting trajectory of the TCP can not be predicted. It can be recreated nevertheless. Multiple positions can be combined to a continuous path. As for single points, the movements between the supporting positions are not predictable but can be recreated. Cartesian motion In case the correct kinematics is used, the TCP can be moved according to a normal perpendicular coordinate system. When under manual control the robot will move the TCP either parallel to one of the coordinate axes or rotate accordingly. Either the global coordinate system of the workspace or the local system of the TCP can be chosen as reference. Linear motion The automatic mode allows to move the TCP to a target position via a straight line. This linear motion requires the correct kinematics and parameters in order to work properly. Like in point-to-point mode a number of positions can be combine to a continuous movement. The edges of the resulting trajectory can be rounded by a variable radius. Collisions Most robot arms feature both software and hardware limit switches as well as end stops for every axis. These only limit the movements of the axes independently and can not prevent collisions of parts of the arm or tool with other parts of the arm or with the surrounding. Neither collisions with the arm itself nor with obstacles within its workspace can be prevented automatically. This means that especially when initiating motions automatically both collisions and damages on both the arm and other parts of the system might occur. All movements that are to be used in any automatic process must be tested under supervision prior to automatic work. The programmer takes full responsibility for the collision avoidance! MAS3D-OperatingManual Neobotix GmbH all rights reserved 7 of 19

8 3 Installing the host computer A common PC system is sufficient to run the Neobotix graphical user interface. In case other interfaces than common Ethernet are to be used appropriate converters might be required. 3.1 Windows operating system Installing the Java Runtime Environment The Neobotix GUI is programmed in Java and thus platform independent. This also means that a Java virtual machine and a library for 3D-calculations must be installed before using the GUI. If there is none or an older version on the host computer use the files in the Java folder on the CD that was delivered together with the robot. Run both.exe -files and follow the instructions on the screen. Installing the GUI The graphical user interface does not need to be installed. Simply copy the folder from the CD to your hard drive. To run the GUI just double-click on start.bat or create a shortcut on your desktop by right-dragging the start.bat -icon onto the desktop and selecting Create shortcut here from the pop-up-menu. 3.2 Linux operating system Installing the Java Runtime Environment Most common Linux distributions like Debian/Ubuntu or OpenSuse already come with an installed Java Runtime Environment. Please make sure that you installed Java 6 Runtime Environment from Sun Microsystems. For Debian/Ubuntu distributions installation starts after entering apt-get install sun-java6-jre on command line as root. For other distributions please use your package manager. Installing the GUI The graphical user interface does not need to be installed. Instead simply copy the folder from the CD to your hard drive. To run the GUI open a terminal, change to the location of PltfGUI and enter java -jar MobileArmSimulation3D.jar 3.3 Setting up the network If ordered, a wireless LAN-device was delivered together with the platform to allow easy connecting to the robot. In case the settings of this device need to be changed, please use the software on the according driver disc and work directly on the platform s onboard computer as described in chapter Maintenance Software. The robot was set up with the network settings stated in Configuration at delievery. Make sure that both robot and host PC are in the same subnet. Please refer to the system administrator of the local computer network. MAS3D-OperatingManual Neobotix GmbH all rights reserved 8 of 19

9 4 First steps 4.1 Network connections Establishing a network connection to all available robot components is the first thing to be done after start-up of the MAS3D-GUI. Depending on the existing hardware, either a single arm, a platform or a complete robot can be connected. Arm Choose Arm Connect to Arm in the main menu. A dialogue appears offering a list of all previous connections which can now be used or deleted. The lower part of the dialogue window can be used to enter a new IP-address. If the mark Remember this host has been set, another window will appear after clicking Connect. In this second dialogue a name can be entered to identify the new connection the next time the GUI is used. If the connection was created successfully, the indicator in the upper right corner of the GUI will turn green. Figure 2: Connection state indicators If no connection was established, the indicator turns red. To disconnect from an arm or to stop trying to connect, choose Arm Disconnect Arm from the main menu. Platform Connecting to a mobile platform is very similar to the steps described above. Choose Platform Connect to Platform from the main menu. To stop trying to connect, click Cancel in the popup window. Interpreter The Python interpreter is a standalone program that makes creating a process control system very easy. Choose Interpreter Connect to Interpreter from the main menu and either select a know connection or enter a new address. If a connection was created successfully the indicator in the upper right corner of the GUI will turn green. Robot If connections to robots have been established before they can be recreated by choosing from the list which is available in the main menu under Robot Connect a Robot >. In order to create a new entry use Robot Manage Robots. MAS3D-OperatingManual Neobotix GmbH all rights reserved 9 of 19

10 Figure 3: The robot management dialogue New robots can be added by clicking Add a new Robot. Once an entry was selected from the list in the left part of the window, its settings can be changed by clicking Modify. Beside changing the robot's name and IP-address, the modules that are available and need to be connected can also be marked. Click Save to store the settings. When clicking Connect Robot in this dialogue and also when using the shortcut described above, the GUI will try to connect to all available modules. To close an open connection use Robot Disconnect current Robot from the main menu. 4.2 Using the mobile platform In case a mobile platform from Neobotix is used in the application, it can be commanded via the MAS3D-GUI and can be sent move to predefined position within the workspace. The platform itself, the landmarks that are saved in the map and also the roadmap can be visualised and simulated in the 3D-view. Both maps of the platform's environment and roadmaps have to be created by using the PlatformCtrlGUI, which is included in delivery of the mobile platform. MAS3D does not provide this functionality and can only used the map and roadmap which are currently loaded in PlatformCtrl. The platform is ready to receive commands as soon as a valid map and roadmap are available for PlatformCtrl, the platform is localised correctly and is connected to the MAS3D-GUI. Preparing the 3D-View The GUI's 3D-View should be set up correctly before commands are sent to the platform. Use View Platform Teach in the main menu to get a 3D-simulation of the platform's workspace. The appropriate 3D-model can now be chosen from the list found under Simulation Load Kinematics...>. When loading a model for the first time or when using very detailed models the loading process might take some time. If no appropriate model is available, Neobotix will provide one. Once the simulation is prepared in this way, a connection to the mobile platform can be established as described in the previous chapter. If there are already a map and a roadmap available on the platform, the landmarks, stations and paths will be added to the 3D-view. MAS3D-OperatingManual Neobotix GmbH all rights reserved 10 of 19

11 In order to adjust the 3D-view, right click into it and select Orbit View from the pop-up menu. Press and hold the left mouse button to rotate the view, press and hold the right button to pan it. Zooming in and out can be done by using the scroll wheel. Figure 4: 3D-view of the platform's surrounding including platform, landmarks and roadmap. Moving to stations The Motion Platform window, which is usually shown directly left of the 3D-view, contains a list of all stations in the current roadmap. Only stations that have been added to the roadmap by using the PlatformCtrlGUI will appear here. Select a target station from the list and click Move To. The platform will automatically switch to automatic mode and move to the chosen station using the predefined paths. The platform's behaviour is defined by its configuration and can not be changed in the MAS3D-GUI. If necessary, please use the PlatformCtrlGUI to adjust the parameters. 4.3 Using the manipulator If a manipulator is available it can be integrated into the GUI's 3D-view. Manual control of the arm is possible as well as saving positions and moving back to them automatically. Several different motion modes for manual and automatic control are supported. As soon as the arm has been installed, powered up and was configured correctly, it can be connected to the MAS3D-GUI. Preparing the 3D-view Click View Arm Simulation in the main menu to activate the 3D-view of the arm's workspace. Then select the appropriate model from the list found under Simulation Load Kinematics...>. MAS3D-OperatingManual Neobotix GmbH all rights reserved 11 of 19

12 After a connection to the arm has been created the 3D-view will be matched to the real arm's pose. Figure 5: 3D-view of a KUKA KR 16 KS The kinematics loaded in the GUI does not affect the calculations in ArmCtrl or the movements of the real arm. Controlling the manipulator without loading a 3D-model is also possible. In case the wrong model has been loaded, its axes will be matched to the real world values but the resulting pose and trajectories in the simulation will not be correct. Single axis motion The Teach window can be used to manually move the arm. Every drive can be moved independently by choosing the single axis motion mode from the list. The slider below the selection box sets the motion speed as percentage of the axis's maximum speed. Always start with low speeds, especially if an axis is already close to its limit or the arm is close to an obstacle. The function Slow Motion can be used to reduce the speed to one tenth of what is set at the slider. This allows extremely slow and accurate movements. The twenty buttons in the Teach window each move one of the ten possible axes in either positive or negative direction. The drives can also be controlled by using the keyboard. Click the button Keyboard OFF at the base of the window to activate the keyboard control. The button will turn orange and changes its caption to Keyboard ON. Now every axis can be moved by pressing one of the two keys beneath the according number key. On English layout keyboards the first axis can be controlled using Z and A. MAS3D-OperatingManual Neobotix GmbH all rights reserved 12 of 19

13 Figure 6: Teach window with activated keyboard control Any mouse click outside the Teach window will deactivate the keyboard control function. Cartesian motion Selecting one of the motion modes Cartesian global or Cartesian local allows the TCP to be moved parallel to the coordinate axes and to be rotated accordingly. Cartesian global uses the global coordinate system which in most cases will match the surrounding workspace. Rotations use virtual axes which run through the TCP but are parallel to the global coordinate axes. Cartesian local uses the tool's coordinate system. This can be very convenient if interactions between the tools and other parts need to be programmed. Rotation will use the local axes directly. Always keep in mind which coordinate system is currently used in order to avoid collisions. Working with point lists Any pose of the arm can be stored in a so called point list for later use. Figure 7: Point list with all parameters shown MAS3D-OperatingManual Neobotix GmbH all rights reserved 13 of 19

14 For each point its name, all drive positions (in radiant) and the 6D coordinates of the TCP (in metres and radiant) are saved. The buttons on the left side of the window provide the following functions: Insert: The arm's current pose is added to the list below the currently marked line. Copy: The currently highlighted point in the list is copied and added below. The new point will use the same name as the original but with an appended asterisk. Replace: All position values of the highlighted point are replaced with the current real world position while the name is kept. Arrow up / down: The marked line is moved up or down in the list by one position. Delete: The marked point is deleted. Clear: All points in the list are deleted. The common file functions for loading, saving and saving as a new file can be accessed via the buttons at the top left of the window. Point lists are always saved on the computer that runs ArmCtrl and not on the computer running the MAS3D-GUI. The amount of information displayed in the list can be chosen from the Combobox to the right of the buttons. To manually change a name or a position value simply double click that cell. Replacing a position value with an asterisk will make ArmCtrl ignore that value and use the position that is currently set instead. This feature can be used to hold additional axes, which are moved only rarely, at a fixed position. Unintentional changes, e. g. when adding additional poses later on, can be avoided. A double arrow (>>) preceding the index of a line indicates that the arm is currently at this position or very close by. Point-to-point motion If at least one point has been added to the list it can be used for automatic movements. Select a target position in the list and set the motion mode to point to point. This is done at the very top of the Motion window. Then set the designated speed in the entry field below the Combobox. The speed has to be et in percentage of the maximum speed. Always start tests slowly. Only increase the speed very carefully and after ensuring that the next motion will not cause any collisions. The most important functions provided by the Motion window are: Move To: Moves the arm to the chosen target position using the given speed. Move Home: Moves the arm back to the home position. Please mind that this pose might not be reachable under some circumstances! Stop: Immediately stops the current motion. Time: The runtime of the current motion is shown here. The display returns to zero after the target position is reached. Override: This slider can be used to dynamically reduce the speed of the current motion. MAS3D-OperatingManual Neobotix GmbH all rights reserved 14 of 19

15 Figure 8: The Motion window When performing PTP-motions all axes will move synchronously and with equal velocity profiles. They will reach their designated position at the same time but they are not coordinates beyond this. Both the resulting trajectories of TCP and the whole arm can not be predicted. But they are repeatable nevertheless. Linear motion When moving linear the TCP will move on a straight line to the target position with the change in orientation being interpolated linearly. Please mind that the resulting trajectory is not checked automatically prior to the motion. This may cause problems and even collisions. Critical situations are for example (but not limited to): Automatically selecting the next position from a list of points that are widely distributed over the workspace. Even if every single position itself can be reached safely, this does not mean that every theoretical connection is also possible. Dynamically calculating the next position based on variable input, like the filling level. The control software can not predict if it is possible to reach the calculated position without collision. Always be careful to use only trajectories which do not cross any obstacles or the robot itself. Under some circumstances it might be necessary to move via supporting points before reaching the final position. It might also help to change the motion mode back to point to point. Especially movements that do not require the tool to keep a given orientation can often be reached in this mode much easier. Only the programmer can be held responsible for the arm's trajectories and for a safe and collision free operation. MAS3D-OperatingManual Neobotix GmbH all rights reserved 15 of 19

16 Moving along paths After adding several positions to the point list these points can be combined to create continuous trajectories. Select both the start and the end point in the list and choose a motion mode. After clicking the Move Path button the arm will move through all points in the list from the start position to the end position. Use the function Move Inv. Path to move the arm in reversed direction. MAS3D-OperatingManual Neobotix GmbH all rights reserved 16 of 19

17 5 Application specific programming A high-level control program can be used to easily and efficiently realise complex processes. This program needs to communicate with all the different software modules running in the application and to coordinate them. Furthermore it might provide a convenient interface between the local process and a top-level control system like a production planning. A proper training in programming Python and how to use the Neobotix protocol will help you to know more about the system and to create clean, easy to use programs that can be maintained and modified without problems. If you do not already have basic knowledge in programming, a training with Neobotix is recommended. 5.1 The Python-Interpreter Neobotix provides a standalone program which significantly reduces the effort needed to create most process control programs. This client can receive source code written in the high level language Python and converts it into Neobotix protocol commands which are then sent to the other modules. Mobile Arm Simulation 3D provides an integrated editor for creating Python scripts from ready-made code blocks. These scripts can than be monitored at runtime for convenient debugging and optimisation. Figure 9: The programming window The buttons at the top of the window offer both common file handling functions as well as debugging tools: Load: Loads an existing program from the hard-drive of the computer that is currently running the interpreter. Save: Save the current program to the hard-drive of the interpreter's computer. SaveAs: Saves the current program in a new file on the hard-drive of the computer that is running the interpreter and uses that file for the further work. Start: Starts execution of the current program. Stop: Stops the currently running program. Break: Pauses the running program. Click Break again to continue the execution. Step: Executes the next step of the program only. MAS3D-OperatingManual Neobotix GmbH all rights reserved 17 of 19

18 Up to four tasks can be created and run at the same time. Use the tab below the buttons to switch between the tasks. The four buttons directly above the editor area provide functions to make programming more convenient: Indent: Shifts the highlighted area to the right. Python uses indentions instead of brackets or keywords to marks a block of code that belongs together. Unindent: This function removes the indention of the highlighted block. Undo: Makes the last change undone. Redo: Recalls the last change that was undone. In order to create a program you can either enter source code directly into the editor or use the code blocks provided by the GUI. Right click into the editor to bring up a pop-upmenu containing the most important functions. Most commands are self-explaining. If further information is required, please refer to the Python Client Programmer's Guide. 5.2 Other external Clients In some cases like research or when working on extraordinarily complex and demanding processes, it might be reasonable to create the process control program by using another programming language. Additional information on the Neobotix protocol and descriptions of all supported commands can be found in the PlatformCtrl Programmer's Guide and in the ArmCtrl Programmer's Guide. For help and information beyond these, please contact Neobotix. MAS3D-OperatingManual Neobotix GmbH all rights reserved 18 of 19

19 6 Legal notes Version information This document has been translated and is not the original. Please refer to the German version in case of uncertainties or questions. Liability Every care has been taken in the preparation of this manual which represents the state of technology at the time of its composing. However, inaccuracies or omissions might occur. Please inform Neobotix in case you notice any. The Neobotix GmbH cannot be held responsible for any technical or typographical errors and reserves the right to make changes to the product and manual without prior notice. Neobotix makes no warranty of any kind with regard to the material contained within this document, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Neobotix GmbH shall not be liable or responsible for incidental or consequential damages in connection with the improper use of one or more of the products described in this manual. Declaration of conformity This product fulfils all relevant directives of the European Union. For further information please contact Neobotix. Downloads and further information Additional information, data sheets and documentations, also for the other products of Neobotix, can be found on our homepage Imprint Neobotix GmbH Weipertstraße 8 10, Heilbronn, Germany Contact: Dipl.-Ing. Till May Tel.: (+49) / may@neobotix.de MAS3D-OperatingManual.odm, edited 19. January 2012 in Heilbronn, Germany MAS3D-OperatingManual Neobotix GmbH all rights reserved 19 of 19