四足机器人对角小跑步态下液压驱动单元位置伺服控制特性参数灵敏度研究  

Characteristic Parameters Sensitivity of Position Servo Control for Hydraulic Drive Unit of a Quadruped Robot in Trotting Gait

作　　者：孔祥东[1,2] 俞滨[2] 权凌霄[1,2] 巴凯先[2] 李满天[3] 

机构地区：[1]先进制造成形技术及装备国家地方联合工程研究中心,河北秦皇岛066004 [2]燕山大学机械工程学院,河北秦皇岛0660040 [3]哈尔滨工业大学机器人技术与系统国家重点实验室,黑龙江哈尔滨150080

出　　处：《机器人》2015年第1期63-73,共11页Robot

基　　金：国家863计划资助项目(2011AA040701);国家973计划资助项目(2014CB046405)

摘　　要：高性能四足仿生机器人的关节由高度集成的液压驱动单元(HDU)驱动,液压传动的引入在带来高性能的同时,也增强了非线性和参数时变性等问题,此外机器人各关节复杂多变的载荷特性,也增大了每个关节HDU的控制难度.为了有针对性地进行对角小跑步态的控制补偿,研究了各HDU位置控制特性的主要影响参数.首先,考虑伺服阀动态特性、压力-流量非线性、伺服缸活塞初始位移及摩擦非线性,搭建其位置伺服控制系统.基于HDU实际结构参数和工作参数建立仿真模型.将HDU实测的摩擦力及对角小跑步态下各关节实测的位移与外负载力数据加载至仿真模型中,得出HDU伺服控制的输出位移及负载力仿真曲线,并进行了试验验证.基于位置伺服控制方程,推导含非线性和时变参数的灵敏度方程表达式,进而求解4个关节工况下HDU输出位移对各参数的灵敏度函数.以采样时间内参数变化引起输出变化的最大值及参数变化引起输出变化绝对值的总和为灵敏度衡量指标,给出指标变化柱形图,分析各参数灵敏度变化规律,并对各HDU中供油压力、比例增益、活塞初始位移及外负载力4个参数的灵敏度指标进行试验验证.最后得到了对角小跑步态下影响各关节HDU位置控制特性的主要和次要影响参数,为位置补偿控制器的设计提供了参考.The joints of high-performance quadruped bionic robot are driven by highly integrated hydraulic drive units （HDUs）. However, the control of each HDU is difficult, because the loading characteristics of each joint are complex and changeable, furthermore the introduction of the hydraulic transmission intensifies the problems such as the strong nonlinearity and the time-varying parameters. In order to achieve compensation control for trotting gait, the main influence parameters of each HDU are investigated. Firstly, a position servo control system is built, in which dynamic characteristics of servo valve, nonlinear characteristics of pressure-flow, initial displacement of servo cylinder piston and friction nonlinearity are taken into consideration. Then, a simulation model is built based on the structure parameters of HDU and operating parameters. By inputting the friction measured by HDUs, and the displacement and external load measured at each joint in trotting gait into the simulation model, the curves about the displacement and load force of HDU servo control are outputted and verified by experiment. Secondly, sensitivity equations considering the influences of the nonlinearity and time-variant parameters are deduced based on the position servo control equation, and sensitivity function of each parameter with regard to output displacement is also obtained under 4-joint working condition. The maximum value of displacement variation and the sum of displacement variation absolute values in the sampling time are both taken as sensitivity indexes, and their values are shown by histogram. The change laws of each parameter’s sensitivity are analyzed. Then, the sensitivity indexes of the four parameters of each HDU are verified by experiment, including supply pressure, proportional gain, initial position of servo cylinder piston and load force. Finally, the primary and secondary influence parameters of position servo control of each joint HDU are obtained for trotting quadruped robot, which provides a reference fo

关 键 词：四足机器人 液压驱动单元 位置伺服控制 灵敏度分析 

分 类 号：TH137[机械工程—机械制造及自动化]