仿蚯蚓移动机器人离散步态控制与相位差控制特性比较  

Comparison of the Discrete Gait Control and Phase-Difference Control for Earthworm-like Locomotion Robots

作　　者：何子瀚 方虹斌 徐鉴[1] HE Zihan;FANG Hongbin;XU Jian(School of Aerospace Engineering and Applied Mecharics.Tongji University,Shanghai 200092,China;Institue of Al and Robotics,Fudan University,Sharnghai 200433,China;Engineering Research Center of Al&Robotics,Ministry of Eiducation,Fudan University,Shanghai 200433,China;Shanghai Engineering Research Center of Al&Robotics,Fudan University,Shanghai 200433,China)

机构地区：[1]同济大学航空航天与力学学院,上海200092 [2]复旦大学智能机器人研究院,上海200433 [3]复旦大学智能机器人教育部工程研究中心,上海200433 [4]复旦大学上海智能机器人工程技术研究中心,上海200433

出　　处：《机器人》2020年第6期697-708,共12页Robot

基　　金：国家自然科学基金重点项目(11932015);国家自然科学基金重大研究计划重点项目(91748203).

摘　　要：从机器人的运动特征、稳态平均速度和波动特性3个方面,对仿蚯蚓移动机器人的离散步态控制策略和相位差控制策略进行比较研究.首先,通过学习蚯蚓的形态学特征,基于舵机-弹簧钢片复合结构,设计并制作了可以执行拮抗变形的仿蚯蚓机器人单元,并将其串联得到一个8单元仿蚯蚓移动机器人.以该机器人为平台,从理论和实验角度研究了机器人在离散步态控制和等相位差控制下的平均速度和运动特征.研究发现,对于2种控制策略,实验得到的平均速度都与理论预测定性吻合,但机器人单元在运动过程中有可能发生显著的向后滑动,使得实验得到的平均速度低于理论预测的平均速度.随后,从波传播的角度对2种控制策略进行了比较.2种控制策略都使得机器人单元的变形以波动的形式沿机器人进行传播,传播方向与机器人运动方向相反,与蚯蚓的后退蠕动波机理保持一致.对于离散步态控制,波传播的波形、波速、波长和周期都与步态参数密切相关;对于相位差控制,波形和周期都由作动规律决定,不能通过相位差进行调节,但波速和波长与相位差成反比.从控制效果来看,机器人在最优的等相位差控制模式下可以实现更高的平均速度,且与蚯蚓的连续特征保持一致,具有一定的优势.From the perspectives of the locomotion characteristics,the steady-state average locomotion speed,and the wave properties,a comparative study between the discrete phase control and the phase-difference control of the earthworm-like locomotion robots is carried out.Firstly,an earthworm-like robot segment which can deform antagonistically is designed and manufactured based on a composite structure of servomotor and spring-steel belts by learning the morphology characteristics of the earthworm.By connecting 8 segments in series,an 8-segment earthworm-like locomotion robot is developed.Taking the developed robot as a platform,the locomotion characteristics and the average locomotion speed corresponding to the discrete gait control and the phase-difference control are examined both theoretically and experimentally.The results reveal that the experimentally obtained average locomotion speeds qualitatively agree with the theoretical predictions for both control strategies.However,some robot segments may slip backward obviously during locomotion such that,quantitatively,the experimental average speeds are lower than the theoretical ones.Then the two control strategies are compared in terms of wave propagation.Both control strategies can propagate the deformations of the robot segments along the robot body in the form of a wave,with the direction being opposite to the locomotion,which agrees with the real earthworm's retrograde peristalsis wave.For the discrete gait control,the waveform,the wave speed,the wavelength,and the period closely relate to the gait parameters.For the phase-difference control,the waveform and the period are determined by the actuation law and cannot be tailored via the phase difference,while the wavelength and the wave speed can be tuned by the phase difference.In terms of the control effect,the optimum identical phase-difference(IPD)control shows some advantages,because the robot can output a high average locomotion speed and is consistent with the earthworm's continuity feature.

关 键 词：仿生机器人:稳态平均速度:移动步态 步态优化 机器人动力学模型:蠕动波 

分 类 号：TP242[自动化与计算机技术—检测技术与自动化装置]