基于弹簧负载倒立摆模型的闭链弹性仿生腿设计

Design of Closed-chain Elastic Bionic Leg Based on Spring Loaded Inverted Pendulum Model

基于弹簧负载倒立摆(SLIP)模型的结构特性,提出一种面向高速奔跑的新型仿生闭链弹性腿结构。以猎豹的腿部骨骼肌肉系统为仿生对象,基于Stephensen-Ⅲ型连杆机构的构型进行演化设计,在腿部杆件结构中加入弹簧,并引入两杆三副,构建一种符合SLIP模型结构和弹性特性的八杆十副腿部机构。基于闭环矢量法对腿部机构进行运动学分析,采用对称弯月形曲线作为期望足端轨迹,提出一种将机构尺度综合分为腿部骨骼尺寸设计与曲柄摇杆尺寸优化的设计方法,得到了满足期望足端轨迹的结构尺寸。进一步采用拉格朗日动力学方程描述单腿足端地面反作用力与驱动力之间的关系。应用Adams软件建立动力学仿真模型,进行质心速度、质心垂直位移、弹簧变形量等仿真分析。经构型设计、运动学分析、动力学仿真和结构设计,验证了该新型闭链弹性仿生腿可实现快速的奔跑步态。

Based on the structural characteristics of spring loaded inverted pendulum (SLIP) model,a new bionic closed-chain elastic leg structure for high speed running is proposed. Taking the leg skeletal muscle system of the cheetah as a bionic object,and evolutionary design based on the configuration of Stephensen-III type linkage mechanism,springs are added to the leg member structure,and two links and three joints are introduced to construct an eight-bar ten-leg mechanism that conforms to the SLIP model structure and elastic characteristics. Based on the closed-loop vector method,the kinematics analysis of the leg mechanism is carried out,and the symmetrical meniscus curve is used as the desired foot end trajectory. A design method that integrates the mechanism scale into the leg bone size design and the crank rocker size optimization is proposed. The structural size that satisfies the desired foot end trajectory. The Lagrangian dynamic equation is further used to describe the relationship between the ground reaction force and the driving force of the single leg. The dynamic simulation model was established by Adams software,and the simulation analysis of centroid speed,centroid vertical displacement and spring deformation was carried out. Through the configuration design,kinematics analysis,dynamics simulation and structural design,it is verified that the new closed-chain elastic bionic leg can achieve a fast running gait.