基于永磁弹簧-摆动导杆的变刚度机构力学特性研究

Research on mechanical properties of variable stiffness mechanism based on permanent magnetic spring-crank shape mechanism

提出一种可用于变刚度关节驱动器的永磁弹簧-摆动导杆变刚度机构,采用轻质绳索牵引改变永磁弹簧气隙间距及初始刚度,同时利用摆动导杆机构运动改变内外圈相对转动所需扭矩大小。分析了变刚度机构的刚度调节机理,阐述了变刚度机械结构。通过永磁弹簧气隙间距-磁力实验结果获得永磁弹簧刚度模型,并根据变刚度机械结构建立的静力学模型分析了机构的力学特性。通过Matlab数值仿真,结果表明永磁弹簧初始刚度对弹簧压缩量及导杆转角的影响规律。根据永磁弹簧与定刚度线性弹簧的绳索拉力变化,对比结果表明采用变刚度永磁弹簧可以进一步增加绳索的拉力变化范围,即可以有效增大机构的刚度变化范围。

A variable stiffness mechanism based on permanent magnetic spring and crank shape mechanism is proposed for variable stiffness actuator,the air gap and initial stiffness of the magnetic spring is changed by light wire,and the torque required for relative rotation of inner and outer rings is changed by the motion of spring-crank shape mechanism.The stiffness regulation mechanism of the variable stiffness mechanism is analyzed,and the mechanical structure of the variable mechanism is described.The stiffness model of permanent magnetic spring is obtained through the air gap and magnetic force experiment results,and the static model is established according to the mechanical structure with variable stiffness to analyze the mechanical properties of the mechanism.Through Matlab numerical simulation results show the influence of initial stiffness of the permanent magnetic spring on the spring compression and the angle of the crank shape mechanism.According to the compared results of the wire force between the permanent magnetic spring and linear stiffness spring,the variable stiffness spring can further increase the tension range of the wire,that is,the stiffness variation range of the mechanism can be effectively increased.