1. Universität zu Lübeck Institut für Technische Informatik Erik Maehle University of Lübeck Institute of Computer Engineering Ratzeburger Allee 160 D-23538 Lübeck E-Mail: maehle@iti.uni-luebeck.de University of Lübeck Institute of Computer Engineering Ratzeburger Allee 160 D-23538 Lübeck E-Mail: maehle@iti.uni-luebeck.de The Organic Robot Control Architecture ORCA and Its Application to the Fault-Tolerant Walking Machine OSCAR * The Organic Robot Control Architecture ORCA and Its Application to the Fault-Tolerant Walking Machine OSCAR * Seminar Organic Computing, Dagstuhl, March 31 – April 4, 2008 Supported by DFG under MA1412/7-1, associated to DFG SPP 1183 Organic Computing Joint Project with University of Osnabrück and Fraunhofer AIS

2. Universität zu Lübeck Institut für Technische Informatik Motivation Autonomous mobile robots in human environments -> unstructured, -> complex control dynamically changing systems environment -> no explicit model -> no explicit fault of the environment model fault-tolerance, safety engineering bottleneck

3. Universität zu Lübeck Institut für Technische Informatik Organic Systems Organic systems adapt dynamically to environment and malfunctions - uncertainties - unknown environment - unforeseen situations Our approach: controlled self-organization Inspiration: autonomic nervous system and immune system Aim: - detect, react, and adapt to malfunctions - avoid critical system states at any time - low cost implementation and engineering

4. Universität zu Lübeck Institut für Technische Informatik Introduction ORCA Architecture Walking Robot OSCAR Self-Organizing Walking Conclusion Overview

5. Universität zu Lübeck Institut für Technische Informatik ORCA - Organic Robot Control Architecture BCU = Basic Control Unit OCU = Organic Control Unit

6. Universität zu Lübeck Institut für Technische Informatik OCU-Architecture - Monitor: anomaly detection - Memory: short term history - Reasoner: hard real-time determination of a counteraction Variant of Observer/Controller Architecture

7. Universität zu Lübeck Institut für Technische Informatik Methodological Approaches - Signals reflecting the ´health´ of a signal or a BCU e.g. - noisiness, confidence of output results, - load state; error state - Adaptive action selection IF movement=blocked THEN activation of commanded behaviour -=5%, activation of non-commanded behaviour +=5% -Learning to treat malfunctions => Learning at OCU-level

8. Universität zu Lübeck Institut für Technische Informatik OSCAR - Organic Self-Configuring and Adapting Robot Hexapod with 18 DOF (Servos) Ground contact Sensor: Simple switch per leg Control Computer: - JControl/Smartdisplay - Servo Driver Modul - I 2 C-Bus Programming Language : JAVA

9. Universität zu Lübeck Institut für Technische Informatik Basic Approaches for Autonomic Walking Stick Insect (Carausius morosus) Leg and Joints AEP: Anterior Extreme Position PEP: Posterior Exreme Position Swing Phase Stance Phase 3 DOF Modelled by WALKNET [Cruse et al. Uni Bielefeld]

10. Universität zu Lübeck Institut für Technische Informatik Distributed Walking Control in OSCAR Swing phase has constant length. Duration of stance phase determines velocity. Slightly different leg orientation depending on leg position (F, M, L). So far only one single rule implemented with circular neighborhood relation for all legs. Single local rule for each leg[i]:

11. Universität zu Lübeck Institut für Technische Informatik Self-Organizing Gait Patterns in OSCAR Slow Gait Tetrapod Gait Tripod Gait Emergent Gait Patterns with Increasing Speed!

12. Universität zu Lübeck Institut für Technische Informatik Insect Walking with Lost Legs [Source: Holk Cruse, Uni Bielefeld]

13. Universität zu Lübeck Institut für Technische Informatik Leg Coordination After Leg Loss for OSCAR Same single rule, only neighborhood relation changes.

14. Universität zu Lübeck Institut für Technische Informatik OSCAR Walking with Lost Middle Legs Simulated Amputation

15. Universität zu Lübeck Institut für Technische Informatik ORCA Organic Robotic Control Architecture

16. Universität zu Lübeck Institut für Technische Informatik Curve Walking Towards a Goal

17. Universität zu Lübeck Institut für Technische Informatik Curve Walking with Lost Leg All 6 legs intact Left leg lost Right leg lost

18. Universität zu Lübeck Institut für Technische Informatik Conclusion ORCA – Organic Robot Control Architecture - BCUs (Basic Control Units) for functional control - OCUs (Organic Control Units) for monitoring, fault adaption and optimization - Learning based on hybrid crisp fuzzy methods and adaptive filters OSCAR - Organic Self-Configuring and Adapting Robot - Self-organizing gait patterns inspired by insects - Monitoring of leg health status by sensor signals from joints and feet - Self-organizing gait patterns also in case of lost legs

19. Universität zu Lübeck Institut für Technische Informatik Current Work - Tools for hybrid crisp fuzzy methods (U Osnabrück) - Integration of learning methods into ORCA/OSCAR - New hardware platform for OSCAR (2 * ARM9 + 6 * ATmega32) - Additional sensors (inertial, ultrasonic, laser, inclinometer, camera,.. ) - Tolerance of less severe leg faults than complete leg losses - More sophisticated methods of anamoly detection (e. g. information theory, fuzzy) - Combination with obstacle avoidance in more challenging environments - Application of ORCA to other robot platforms (e.g. fish-like underwater robots) Acknowledgement of contributions of ORCA Group Members Werner Brockmann (U Osnabrück), Adam El-Sayed-Auf, Karl-Erwin-Grosspietsch (Fraunhofer AIS), Bojan Jakimovski, Marek Litza, Florian Mösch