The effects of ground compliance on flexible planar passive biped dynamic walking

Wu, Yao; Yao, Daojin; Xiao, Xiaohui

doi:10.1007/s12206-018-0336-0

Cited by 14 publications

(5 citation statements)

References 27 publications

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“…The knowledge of deformable terrain properties, particularly the stiffness, has major implications in modeling the robot walking dynamics, which is the key to achieve stable gait patterns. Prior studies on walking stabilization chose to model such walking dynamics using pre-identified stiffness or damping constants (Wittmann et al, 2016;Wu et al, 2018;Hashimoto et al, 2012). However, it is unlikely for robots to access such terrain properties in advance when deployed to unknown environments.…”

Section: In-situ Terrain Classification and Estimationmentioning

confidence: 99%

A Holistic Approach to Human-Supervised Humanoid Robot Operations in Extreme Environments

Wonsick

Long²,

Onol

et al. 2021

Front. Robot. AI

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Nuclear energy will play a critical role in meeting clean energy targets worldwide. However, nuclear environments are dangerous for humans to operate in due to the presence of highly radioactive materials. Robots can help address this issue by allowing remote access to nuclear and other highly hazardous facilities under human supervision to perform inspection and maintenance tasks during normal operations, help with clean-up missions, and aid in decommissioning. This paper presents our research to help realize humanoid robots in supervisory roles in nuclear environments. Our research focuses on National Aeronautics and Space Administration (NASA’s) humanoid robot, Valkyrie, in the areas of constrained manipulation and motion planning, increasing stability using support contact, dynamic non-prehensile manipulation, locomotion on deformable terrains, and human-in-the-loop control interfaces.

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Section: In-situ Terrain Classification and Estimationmentioning

confidence: 99%

A Holistic Approach to Human-Supervised Humanoid Robot Operations in Extreme Environments

Wonsick

Long²,

Onol

et al. 2021

Front. Robot. AI

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“…The normal and tangential contact forces were described as follows. 34 The normal contact force F n was described by the normal contact model, which describes the rigidity of the ground…”

Section: Contact Modelmentioning

confidence: 99%

Adaptive stiffness control of passivity-based biped robot on compliant ground using double deep Q network

Yao

Guo

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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Passive dynamic walking exhibits human-like and energy-efficient gait. Biologically inspired compliance introduced to flexible passivity-based robot would be helpful to generate stable locomotion. However, designing adaptive controller for flexible biped on compliant ground still remains a challenge. This paper aims to design an adaptive and model-free stiffness controller for passivity-based flexible biped on compliant ground, where the hip stiffness is modulated by double deep Q network. One benefit of the double deep Q network is that adaptive stiffness control policy could be directly learned from inputs. At first, passive dynamic walking gait is utilized as a reference trajectory during double deep Q network training. Then the trained double deep Q network is used as adaptive stiffness controller for biped on compliant ground. Simulation results show that the passivity-based biped robot could walk in such walking cases as disturbed initial condition, level compliant ground, downslope slippery compliant surface, and varying compliance environments. The adaptive stiffness controller would be used to make the passivity-based biped robot adapt to the environmental changes.

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“…In our previous works, hybrid dynamics model for compliant biped robot has been set up, 29 and structural parameters of PDW were optimized to get stable locomotion with high walking velocity. 30 Besides, adaptive model-free controllers using RL were proposed to stabilize PDW-based robots, improving robustness to disturbance and time varying environments, while maintain PDW’s merits of human-like motion and high energy efficiency.…”

Section: Introductionmentioning

confidence: 99%

A hybrid chaotic controller integrating hip stiffness modulation and reinforcement learning-based torque control to stabilize passive dynamic walking

Qiao

Yao

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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Implementation of bipedal stable walking has attracted a lot of interest. Passive dynamic walking (PDW) is one promising manner to generate natural bipedal walking with high energy efficiency. However, how to improve stability and versatility of PDW-based robot against disturbance and time varying environments is still a big challenge in robotics. Chaos and bifurcations are intrinsic features of biped dynamic walking, which are important reasons for the failure of PDW. Thus a hybrid chaotic controller to stabilize chaos and bifurcations of PDW was proposed in this paper. At first, the dynamics model of compliant biped robot was set up, and routine to bipedal chaotic motions was found through parameter study. Then one hybrid chaotic controller integrating hip stiffness modulation and hip impulse torque control was developed, where hip impulse torque control based on reinforcement learning was trained to get state variables close to fixed point of PDW, and then hip stiffness modulation was conducted based on Ott-Grebogi-Yorke method to stabilize unstable motions of fixed point. Simulation results showed that period-1 stable walking could be gained for biped robots from chaotic motions, against original value disturbance, force disturbance and in time varying environments. The proposed hybrid chaotic controller could be used to stabilize bipedal chaotic motions and make the passivity-based robot become robust and versatile to disturbed and time changing environments.

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The effects of ground compliance on flexible planar passive biped dynamic walking

Cited by 14 publications

References 27 publications

A Holistic Approach to Human-Supervised Humanoid Robot Operations in Extreme Environments

A Holistic Approach to Human-Supervised Humanoid Robot Operations in Extreme Environments

Adaptive stiffness control of passivity-based biped robot on compliant ground using double deep Q network

A hybrid chaotic controller integrating hip stiffness modulation and reinforcement learning-based torque control to stabilize passive dynamic walking

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