A Geometric Sufficient Condition for Contact Wrench Feasibility

Li，Shenggao1; Chen，Hua2; Zhang，Wei2; Wensing，Patrick M.1

2022

10.1109/LRA.2022.3217687

IEEE Robotics and Automation Letters   Impact Factor & Quartile

2377-3774

2377-3766

A fundamental problem in legged locomotion is to verify whether a desired trajectory satisfies all physical constraints, especially those for maintaining contacts. Although foot tipping can be avoided via the Zero Moment Point (ZMP) condition, preventing foot sliding and twisting leads to the more complex Contact Wrench Cone (CWC) constraints. This paper proposes an efficient algorithm to certify the inclusion of a net contact wrench in the CWC on flat ground with uniform friction. In addition to checking the ZMP criterion, the proposed method also verifies whether the linear force and the yaw moment are feasible. The key step in the algorithm is a novel exact geometric characterization of the yaw moment limits in the case when the support polygon is approximated by a single supporting line. We propose two approaches to select this approximating line, providing an accurate inner approximation of the ground truth yaw moment limits with only $ 18.80\%$ (resp. $7.13\%$) error. The methods require only $1/150$ (resp. $1/139$) computation time compared to the exact CWC based on conic programming. As a benchmark, approximating the CWC using square friction pyramids requires similar computation time as the exact CWC, but has $>19.35\%$ error. Unlike the ZMP condition, our method provides a sufficient condition for contact wrench feasibility.

Body Balancing Foot Force Friction Humanoid and Bipedal Locomotion Humanoid robots Legged locomotion Robots Sufficient conditions Whole-Body Motion Planning and Control

SCI

English

Others

WOS:000880643400003

2-s2.0-85141437995

Scopus

1.University of Notre Dame, South Bend, IN, US
2.Southern University of Science and Technology, Shenzhen, China

Li，Shenggao,Chen，Hua,Zhang，Wei,et al. A Geometric Sufficient Condition for Contact Wrench Feasibility[J]. IEEE Robotics and Automation Letters,2022,7(4):12411-12418.

Li，Shenggao,Chen，Hua,Zhang，Wei,&Wensing，Patrick M..(2022).A Geometric Sufficient Condition for Contact Wrench Feasibility.IEEE Robotics and Automation Letters,7(4),12411-12418.

Li，Shenggao,et al."A Geometric Sufficient Condition for Contact Wrench Feasibility".IEEE Robotics and Automation Letters 7.4(2022):12411-12418.