下肢外骨骼助力机器人关节驱动设计及试验分析

Design on Articular Motion & Servo Driving with Experimental Analysis for Lower Limb Exoskeleton Robot

针对人体下肢关节特点与助行要求,设计了外骨骼机器人关节结构;通过ADAMS软件仿真,分析了外骨骼机器人水平助行过程中关节功率配置需求,根据关节需求设计了外骨骼电液伺服驱动系统;为满足外骨骼机器人对人体下肢关节助力及柔顺性要求,提出了基于关节误差估计的PID控制方法。详细介绍了外骨骼机器人下肢关节结构的运动形式与技术参数,优化配置了关节结构的运动范围与驱动行程,对该机器人进行了运动学分析并通过外骨骼的典型动作进行验证;划分了外骨骼助行过程中步态与关节驱动映射,给出误差估计与补偿PID控制的具体参数;分别从关节跟踪与助力功率的角度,量化分析、对比了基于关节误差估计与常规PID两种控制方法的助力指标参数。试验结果表明,所设计外骨骼关节与驱动系统可实现穿戴者助力行走;对比常规PID控制,抑制了关节驱动控制输出区间的不连续,改善了关节跟踪误差,提升了助力效果与柔顺性。

According to the characteristics of human lower limb and requirements of joint motion for level walking,the mechanical structures were designed on exoskeleton robot.The simulation on power of joints during requirements of level walking were analyzed and simulated with ADAMS software,and electro-hydraulic driving was designed on exoskeleton joints for locomotion.A PID control method based on joint error estimation was proposed to meet the requirements of joints assistance and flexibility for human lower limb.The locomotion parameters of joints structure are introduced in detail,for which motion range and driving stroke of the exoskeleton robot are optimized.The kinematics of the robot was analyzed and verified by typical actions of the exoskeleton.The mapping of gait and joint driving in the process of exoskeleton walking is divided,and the PID control with error estimation and compensation are given.From the perspective of joint tracking and power,index parameters of two control methods based on joint error estimation and conventional PID are analyzed and compared quantitatively.Finally,experimental results show that the designed joints and driving system of exoskeleton could have a great affection on power assistant for wearer.Compared with common PID control,the discontinuity of joint driving control output interval is suppressed,the joint tracking error is improved and power walking is much more compliant.