BioRob: A Really Lightweight and Safe Robot Arm for Mobile Human-Robot Interaction

Transcription

1 BioRob: A Really Lightweight and Safe Robot Arm for Mobile Human-Robot Interaction Dipl.-Ing. Thomas Lens, Prof. Dr. Oskar von Stryk Technische Universität Darmstadt Department of Computer Science Simulation, Systems Optimization and Robotics Group T. Lens, O. von Stryk BioRob Augsburg, January 26,

2 BioRob: Introduction T. Lens, O. von Stryk BioRob Augsburg, January 26,

3 Motivation: Automation in SMEs SMEs: Large potential market for robot automation SMErobot.org Machine chaining task Palletizing task Planting task Potential benefits of using robots instead of humans: Higher productivity and cost efficiency Higher precision (e.g. for inspection of surfaces) Less pollutive (e.g. for handling of cell probes) Relief of humans from boring work tasks Challenge of frequently changing production processes! T. Lens, O. von Stryk BioRob Augsburg, January 26,

4 Key Requirements for Assistant Robots Human-robot interaction: High collision safety Intuitive robot programming Easy change of work place & task No fence (if possible) Lightweight design Return on invest: Appropriate cost for installation and operation T. Lens, O. von Stryk BioRob Augsburg, January 26, BioRob SMErobot.org

5 State of the Art Rigid robot arms in the same workspace as humans Payload : deadweight = 1:5 1:12 Shock protecting material and slow movement Virtual fence : external sensors for measuring the humanrobot distance KR3SI Katana rob@work (Variable) compliance and elasticity key elements to the superior safety and performance of biological arms Virtual compliance Force/moment sensing, impedance control Performance limited by bandwidth of sensors and motors Speed/power limited by DIN EN ISO DLR LWR III T. Lens, O. von Stryk BioRob Augsburg, January 26,

6 50 Years of Robotics Unimate (1959) KUKA DLR ABB Honda Kinematic chains of rigid joints and links Mechanical elasticity considered harmful! T. Lens, O. von Stryk BioRob Augsburg, January 26,

7 Arm Design Industrial Robot Biological Manipulator Fig.: KUKA T. Lens, O. von Stryk BioRob Augsburg, January 26,

8 State of the Art: Compliant Robot Actuation New actuators with compliance Electroactive polymers: yet too weak Pneumatic actuators: - High forces possible, but compressibility of air/gases limits position accuracy and velocity control - Low mobility: onboard compressor or cable supply - Noisy (often) VU Brussels FerRobotics Festo Fluidic (rotary) elastic actuators Shape memory alloys T. Lens, O. von Stryk BioRob Augsburg, January 26,

9 State of the Art: Compliant Robot Actuation Combinations of rotary electric actuators with mechanical elasticity Natural compliance: - Inherent safety of objects in collisions, protection of motors and gears - Potential of higher performance (energy conserved in mechanical elasticity) - Accuracy & control & design? Series elastic actuator (Pratt/Williamson 1995) (MIT) Variable stiffness actuator (DLR, 2007), MACCEPA (VU Brussels), VIACTORS EU-Project (since 2009, Albu-Schäffer/DLR, Bicchi/U Pisa, Lefeber/VU Brussels et al.) - Typically 2 electrical actuators per compliant joint T. Lens, O. von Stryk BioRob Augsburg, January 26,

10 Series Elastic Actuation (MIT) Cog Hammering (R. Brooks et al., 1995) T. Lens, O. von Stryk BioRob Augsburg, January 26,

11 Antagonistic Series Elastic Actuation B. Möhl (1995) T. Lens, O. von Stryk BioRob Augsburg, January 26,

12 BioRob Project Approach Industrial Robot Biological Manipulator BioRob-Arm Fig.: KUKA T. Lens, O. von Stryk BioRob Augsburg, January 26,

13 Lightweight Design Bending under load rigid links rigid drives (1 per joint) Rigid series kinematic robot arm T. Lens, O. von Stryk BioRob Augsburg, January 26, Solution approaches: antagonistic elastic actuation BioRob arm No relief from bending stress when adding elasticity directly in actuated joints!

14 Elasticity and Vibrations T. Lens, O. von Stryk BioRob Augsburg, January 26, Actuated motion (2 DoF model) (B. Möhl)

15 Vibration Damping T. Lens, O. von Stryk BioRob Augsburg, January 26, Actuated motion (2 DoF model) (B. Möhl)

16 Repeatability T. Lens, O. von Stryk BioRob Augsburg, January 26, DoF model

17 Repeatability T. Lens, O. von Stryk BioRob Augsburg, January 26, DoF model

18 High Safety in Collisions T. Lens, O. von Stryk BioRob Augsburg, January 26, DoF model (B. Möhl)

19 Robot Arm Control Industrial Robot BioRob Arm X4 Cascade of single-joint control (most often) Feedback control (almost only) Well researched T. Lens, O. von Stryk BioRob Augsburg, January 26, Multi-joint control (model based) New methods needed: PTP motion, collision handling, teach-in programming, Feedback and feedforward control advantageous

20 BioRob: Dynamic Modeling and Control T. Lens, O. von Stryk BioRob Augsburg, January 26,

21 Joint Actuation Model Schematic diagram of a joint elastically actuated by cables and pulleys Modeling abstraction with reflected variables T. Lens, O. von Stryk BioRob Augsburg, January 26,

22 Kinematics Model: Coupled Joints Equilibrium joint angles: Defined by position of motors Dependent on position of joint 3 T. Lens, O. von Stryk BioRob Augsburg, January 26,

23 Dynamics Model reflected mechanical motor dynamics motor torque manipulator dynamics motor-joint coupling Elastical and damped coupling between motors and joints: Cables and pulleys: damping not neglectable Nonlinear joint spring characteristic curve T. Lens, O. von Stryk BioRob Augsburg, January 26,

24 Controller Design in Simulation Identification of static and dynamic robot parameters from experiments Model-based controller design Desired motor trajectory: Controller design in simulation with identified parameters gravitational forces kinematic coupling T. Lens, O. von Stryk BioRob Augsburg, January 26,

25 Experimental Trajectory Tracking T. Lens, O. von Stryk BioRob Augsburg, January 26, Experimental data from pick-and-place experiment

26 Trajectory Tracking and Total Power Consumption Average power consumption: 12 W T. Lens, O. von Stryk BioRob Augsburg, January 26,

27 Pick-and-Place: Programming by Demonstration T. Lens, O. von Stryk BioRob Augsburg, January 26, Programming by demonstration

28 Performing the Pick-and-Place Task T. Lens, O. von Stryk BioRob Augsburg, January 26,

29 High Safety in Collisions T. Lens, O. von Stryk BioRob Augsburg, January 26, BioRob-Arm-X4

30 BioRob: Summary and Outlook T. Lens, O. von Stryk BioRob Augsburg, January 26,

31 BioRob Arm Potential Lightweight Strong Accurate Compliant and Safe Cooperative Biocompatible Really lightweight robot arm: e.g. BioRob-X4 See our demo today! 2kg payload, ~5kg total weight (including control & power devices!), 0.7kg moving arm mass Range: 94cm (from base), 67cm (from 2 nd joint/shoulder) Ability to estimate unknown payloads and joint moments w/o additional sensors Low power requirements (12-24V), low energy consumption Moderate cost for installation and operation T. Lens, O. von Stryk BioRob Augsburg, January 26, New industrial SME applications as 3 rd hand New research opportunities in control (e.g. bio-inspired, feedback-feedforward control strategies)

32 BioRobAssist: Neue Anwendungsszenarien für teilautonome Prüf-, Inspektions- und Handlingroboter Handlingaufgaben Seidel GmbH+Co.KG, Marburg Prüf- und Inspektionsaufgaben Endress+Hauser Conducta GmbH, Waldheim Greifen und Einsortieren Entwicklungspartner: Verkettung von Produktionsschritten T. Lens, O. von Stryk BioRob Augsburg, January 26, Messstellen für die Flüssigkeitsanalyse in der Umweltund Prozessindustrie

33 Spin-Off BioRob GmbH Founded in 09/2010 BioRobArm now available for purchase (first units have been delivered) Please watch for us in 2011 at: Hannover Messe, Biotechnica, Productronica, IEEE IROS T. Lens, O. von Stryk BioRob Augsburg, January 26,

34 BioBiped Robot Project (TU Darmstadt & U Jena) T. Lens, O. von Stryk BioRob Augsburg, January 26,

35 Internationale Entwicklung! Internationale Konkurrenz bereitet großen Sprung vor. Viel innovativere, risikoreichere Ansätze in D nötig als bisher! Christensen (Georgia Tech) T. Lens, O. von Stryk BioRob Augsburg, January 26,

36 Thank You very much for Your attention! Many thanks to the team: TU Darmstadt, FG SIM S. Kohlbrecher, J. Kunz, T. Lens, D. Thomas, O. von Stryk TETRA GmbH, Ilmenau A. Karguth, C. Trommer, S. Amthor, P. Schütz BioRob GmbH, Darmstadt J. Röhlinger, J. Kunz Extern: B. Möhl (ehemals Universität des Saarlandes) T. Lens, O. von Stryk BioRob Augsburg, January 26,