摘要
磁流变阻尼器控制的四连杆关节瞬时转动中心是变化的,仿生特性好,但机构模型复杂,模拟人腿关节运动时变轨迹跟踪较为困难。基于此,提出行走机器人四连杆仿生膝关节机构,建立虚拟样机、机构动力学简化模型和磁流变阻尼器Bingham模型。基于瞬时转动中心和简化的关节几何中心,引入大小腿长度变化以减少模型误差。设计计算力矩加比例微分反馈控制算法来控制关节摆动。采用Lyapunov方法,分析在模型存在误差情况下,控制算法的收敛性和跟踪误差大小。在虚拟样机上对阻尼力和关节摆动运动进行仿真,在样机上对控制算法进行验证。试验结果表明,引入瞬时中心和几何中心,可降低模型误差,控制算法轨迹跟踪精度能满足行走机器人行走要求。
With varying instant central of rotation, 4 links knee joint controlled by magnetic rheclogical intelligent damper is more bionic than 2 links joint. But its machine model is complex, and rotation motion control is a difficult nonlinear time varying system＇s tracking control. Firstly, virtual prototype and dynamic model of biped robot leg with 4 links bionic knee joint, and Bingham model of MR damper are built. Secondly, based on the centre of instant central rotation and joint geometry, a simplified model is presented. Thigh and crus length changing is computed in the proposed model to reduce model errors. Computed torque and PD feedback control algorithm is put forward and designed for robot leg swing motion control. According to Lyapunov function, the co nvergence is proved based on dynamic model with modeling errors. The simulations on virtual prototype and sample machine test are done. The relation between MR damper force and knee joint rotation gait is illustrated. All results indicate that using instant centre of rotation and varying link length in dynamic modeling can reduce model errors. Based on the proposed simplified model, computed torque and PD feed back control is good for walking control of biped robot with 4 links bionic knee joint.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2008年第1期179-183,共5页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(60475036)。
关键词
机器人
仿生关节
磁流变智能阻尼器
计算力矩控制
收敛
Robot Bionic joint Magnetic rheological intelligent damper Computed torque control Convergence
