Posture Control of Legged Locomotion Based on Virtual Pivot Point Concept

This paper presents a novel control approach for achieving robust posture control in legged locomotion,specifically for SLIP-like bipedal running and quadrupedal bounding with trunk stabilization.The approach is based on the virtual pendulum concept observed in human and animal locomotion experiments,which redirects ground reaction forces to a virtual support point called the Virtual Pivot Point(VPP)during the stance phase.Using the hybrid averaging theorem,we prove the upright posture stability of bipedal running with a fixed VPP position and propose a VPP angle feedback controller for online VPP adjustment to improve performance and convergence speed.Additionally,we present the first application of the VPP concept to quadrupedal posture control and design a VPP position feedback control law to enhance robustness in quadrupedal bounding.We evaluate the effectiveness of the proposed VPP-based controllers through various simulations,demonstrating their effectiveness in posture control of both bipedal running and quadrupedal bounding.The performance of the VPP-based control approach is further validated through experimental validation on a quadruped robot,SCIT Dog,for stable bounding motion generation at different forward speeds.

Development of Minimalist Bipedal Walking Robot with Flexible Ankle and Split-mass Balancing Systems

This paper presents a novel design of minimalist bipedal walking robot with flexible ankle and split-mass balancing systems.The proposed approach implements a novel strategy to achieve stable bipedal walk by decoupling the walking motion control from the sideway balancing control.This strategy allows the walking controller to execute the walking task independently while the sideway balancing controller continuously maintains the balance of the robot.The hip-mass carry approach and selected stages of walk implemented in the control strategy can minimize the efect of major hip mass of the robot on the stability of its walk.In addition,the developed smooth joint trajectory planning eliminates the impacts of feet during the landing.In this paper,the new design of mechanism for locomotion systems and balancing systems are introduced.An additional degree of freedom introduced at the ankle joint increases the sensitivity of the system and response time to the sideway disturbances.The efectiveness of the proposed strategy is experimentally tested on a bipedal robot prototype.The experimental results provide evidence that the proposed strategy is feasible and advantageous.

A survey of the development of quadruped robots: Joint configuration, dynamic locomotion control method and mobile manipulation approach

Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and infrastructure construction. The development route, mechanisms design, control methods and mobile manipulating approaches of the quadruped robots are surveyed in this article. Firstly, the development route of the quadruped robot is combed, as the references of the forecast of the future work on quadruped robots. Then the bionic structure and the motion control method of the quadruped robot is summarized, the advantages and disadvantages are analyzed in aspects of gait switching, terrain adaption and disturbance resistance. Subsequently, aiming at the mobile manipulation of the quadruped robot, the representative leg-arm collaborative robots and the multi-task-oriented Whole-body Control (WBC) methods are introduced. Finally, the summary and future work of the quadruped robots is given.