Compliance Control and Analysis for Equivalent Hydraulic Legs

Guangrong Chen,Sheng Guo,Bowen Hou,Junzheng Wang

doi:10.1109/access.2020.3015333

Guangrong Chen, Sheng Guo + Show 2 more

Open Access

https://doi.org/10.1109/access.2020.3015333

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Abstract

In this article, the compliant behavior of an equivalent hydraulic leg is achieved by combining active compliance control of hydraulic cylinder with a passive spring at its end effector. Firstly, a position-based active compliance control is proposed based on impedance control to reduce the contact impact. Secondly, the stability of proposed compliance controller and the range of impedances (Z-width) of compliance control are analyzed, and the design procedure of proposed compliance controller is given out. Finally, experimental results show that the contact impacts could be well handled by the proposed control method. This research provides an insight for the compliance control of hydraulic legged robots.

Highlights

Nowadays, legged robots have been a research hotspot and gained various attention, especial for biped robots and quadruped robots
In the DARPA Robotics Challenge (DRC) in 2015, many legged robots including Atlas are developed to compete on finishing a series of challenging tasks for their relevance to disaster response [19]
A compliance controller combining position-based active compliance control with a passive spring is employed on an equivalent hydraulic leg to achieve the compliant behavior

Summary

INTRODUCTION

Nowadays, legged robots have been a research hotspot and gained various attention, especial for biped robots and quadruped robots. In the force-based impedance control, the force track control is still achieved by the change of displacement of active actuator As both two method cannot handle the first contact impact well. Robots are expected to be employed for a variety of tasks involving interaction with dynamic environments, like material transportation, geographic expedition and disaster rescue etc [39] In these cases, the environmental terrains are normally unstructured or unknown and robots should confront with impacts and crashes when negotiating the contact. A compliance controller combining position-based active compliance control with a passive spring is employed on an equivalent hydraulic leg to reduce the contact impact. A compliance controller combining position-based active compliance control with a passive spring is employed on an equivalent hydraulic leg to achieve the compliant behavior.

PLATFORM AND MODEL

EXPERIMENTS

COMPARATIVE EXPERIMENTS OF ACTIVE COMPLIANCE WITH DIFFERENT SYSTEM PARAMETERS

CONCLUSION