Asguard: A Hybrid Legged-Wheel Security and SAR- Robot Using Bio-Inspired Locomotion for Rough...

Asguard: A Hybrid Legged-Wheel Security and SAR-Robot Using Bio-Inspired Locomotion for Rough Terrain

DFKI- Labor Bremen & Universität Bremen

Forschungsgruppe Robotik

Director: Prof. Dr. Frank Kirchner

www.dfki.de/robotics

[email protected]

2 / 14ASGUARD: A Hybrid Legged-Wheel Security and SAR-Robot Using Bio-Inspired Locomotion for Rough Terrain

Dipl. Inf. Markus Eich

Overview

• Motivation for Legged-Wheel Locomotion• The Physical Robot Asguard• CPG-based Locomotion Control• Adaptive Proprioceptive Control• Results



Motivation for Legged-Wheel Locomotion

• Wheels are most suitable for high velocities

• Legs are suitable to overcome obstacles and climb stairs

• Many robotic applications in security and SAR fields need both

• Combining the advantages of wheeled and legged locomotion in one system

ARAMIES Walking Robot

Asguard Hybrid Legged-Wheel Robot



The Physical Robot Asguard (I)

• Five compliant legs are mounted around an axis shaft• Elastic foot tips reduce shock for high velocities• Elastic spinal column (passive) for ground adaptation

Asguard compliant leg Shock absorbing foot tip Schematic of stair climbing



The Physical Robot Asguard (II)

LiPoly Battery30V/10Ah

PC 104 Onboard

Computer

Modular Camera Section

(Zoom / IR)

Custom FPGA Sensor/Motor Board

4x Faulhaber 24V DC 83W

Weight: 11.5 kg

95 cm

50 cm



CPG Based Locomotion Control (I)

• Central Pattern Generators in biological systems are self-sustaining neural circuits which produce rhythmic oscillations.

• These patterns can be found in biological systems (from insects to humans), where rhythmic actuation is required (e.g. walking, chewing).

Eight legged scorpion robot Hadrurus arizonensis



CPG Based Locomotion Control (II)



Adaptive Proprioceptive Control (I)

• Key idea and innovation for compliant legs: No fixed motion pattern for different types of terrain Adjustment of CPG internal control loop Use of „adaptive spring“, based on proprioceptive data (energy

distribution for each leg)

Adaptive control based on proprioceptive data



Adaptive Proprioceptive Control (II)

• Online adaptation of internal position controller by adjusting the proportional factor in correlation with the current discrepancy

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Fig. 1: Front Left Fig. 2: Front Right

Fig. 3: Rear Left Fig. 4: Rear Right

Results (I): Phase Sync Without Adaptive Control



Results (II): Phase Sync With Adaptive Control

Fig. 1: Front Left Fig. 2: Front Right

Fig. 3: Rear Left Fig. 4: Rear Right



Results (III): Demonstration of Mobility



Outlook

• Investigation about different gaits in terms of efficiency/speed

• Research about adaptive gait transitions• Next prototype (waterproof) already under development• Increase autonomy in terms of navigation under Asguards

odometry constraints



Questions?/Comments?

Thank you for your attention

Asguard: A Hybrid Legged-Wheel Security and SAR- Robot Using Bio-Inspired Locomotion for Rough...

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