足式机器人腿部零动力元机构设计及运动学分析

Design and kinematics analysis of leg unpowered mechanism of foot Robot

为降低足式机器人腿部质量,提高机器人动力学特性,同时避免电机的频繁往复运转,基于4杆机构的运动传递原理,设计了一种足式机器人腿部机构,将大腿小腿的驱动电机布置于机器人腹部,实现了腿部零动力单元化。基于D-H法,推导了腿部机构的运动学模型,利用Matlab进行了运动学数值求解,通过与ADAMS虚拟样机仿真结果的对比,验证了理论推导的正确性。基于运动学模型,通过计算对比分析4杆机构各构件不同杆长条件下,腿部关节的运动学响应关系,并对足端轨迹进行了对比分析,确定了腿部机构杆长的最佳尺寸。研究表明:将曲柄摇杆机构应用于足式机器人腿部机构的驱动,可充分发挥4杆机构的运动优势,同时避免急回特性对构件运动产生的不利影响,从而提高机器人的行走效率,为后续实验样机的设计与搭建提供了参考。

In order to reduce the leg mass of the foot robot,improve the dynamics characteristics of the robot,and avoid the frequent reciprocating operation of the motor,a foot robot leg mechanism was designed based on the motion transfer principle of the four-bar mechanism.The driving motor of the leg was arranged in the abdomen of the robot,realizing the unification of unpowered mechanism of leg.Based on D-H method,the kinematics model of leg mechanism was derived,and the kinematics was solved numerically by Matlab.The correctness of theoretical derivation was verified by comparing with the simulation results of ADAMS virtual prototype.Based on the kinematic model,the kinematic response of leg joints under the condition of different rod lengths of each member of four-bar mechanism was analyzed and compared,and the foot trajectory was analyzed,and the optimal rod length of leg mechanism was determined.The results show that the application of crank and rocker mechanism to the driving of leg mechanism of foot robot can give full play to the motion advantages of four-bar mechanism,and avoid the adverse effects of quick-return characteristics on the movement of components,so as to improve the walking efficiency of the robot.This study provides a reference for the design and construction of subsequent experimental prototypes.