Characteristic Parameters Sensitivity of Position Servo Control for Hydraulic Drive Unit of a Quadruped Robot in Trotting Gait
KONG Xiangdong1,2, YU Bin2, QUAN Lingxiao1,2, BA Kaixian2, LI Mantian3
1. National Engineering Research Center for Local Joint of Advanced Manufacturing Technology and Equipment, Qinhuangdao 066004, China;
2. School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China;
3. State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150080, China
孔祥东, 俞滨, 权凌霄, 巴凯先, 李满天. 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[J]. 机器人, 2015, 37(1): 63-73.DOI: 10.13973/j.cnki.robot.2015.0063.
KONG Xiangdong, YU Bin, QUAN Lingxiao, BA Kaixian, LI Mantian. Characteristic Parameters Sensitivity of Position Servo Control for Hydraulic Drive Unit of a Quadruped Robot in Trotting Gait. ROBOT, 2015, 37(1): 63-73. DOI: 10.13973/j.cnki.robot.2015.0063.
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 for position compensation controller design.
 李满天,蒋振宇,郭伟,等.四足仿生机器人单腿系统[J].机器人,2014,36(1):21-28.// Li M T, Jiang Z Y, Guo W, et al. Leg prototype of a bio-inspired quadruped robot[J]. Robot, 2014, 36(1): 21-28. 王立鹏,王军政,汪首坤,等.基于足端轨迹规划算法的液压四足机器人步态控制策略[J].机械工程学报,2013,49(1):39-44.// Wang L M, Wang J Z, Wang S K, et al. Strategy of foot trajectory generation for hydraulic quadruped robots gait planning[J]. Journal of Mechanical Engineering, 2013, 49(1): 39-44. 黄博,赵建文,孙立宁.基于静平衡的四足机器人直行与楼梯爬越步态[J].机器人,2010,32(2):226-232.// Huang B, Zhao J W, Sun L N. Straight walking and stair climbing gait of quadruped robot based on static balance[J]. Robot, 2010, 32(2): 226-232. 丁良宏,王润孝,冯华山,等.浅析BigDog四足仿生机器人[J].中国机械工程,2012(5):505-514.// Ding L H, Wang R X, Feng H S, et al. Brief analysis of a BigDog quadruped robot[J]. China Mechanical Engineering, 2012(5): 505-514. Log V G, Koo I M, Trong T D, et al. Sensing and control of quadruped walking and climbing robot over complex environment[C]//IEEE/RSJ International Conference on Intelligent Robots and Systems. Piscataway, USA: IEEE, 2008: 3884-3889. Semini C. HyQ-Design and development of a hydraulically actuated quadruped robot[D]. Liguria, Italy: University of Genoa, 2008: 8-35. Song X M, Kong F Z, Zhan C S, et al. Parameter identification and global sensitivity analysis of Xin'anjiang model using meta-modeling approach[J]. Water Science and Engineering, 2013, 6(1): 1-17.  Hall J W, Boyce S A, Wang Y L, et al. Sensitivity analysis for hydraulic models[J]. Journal of Hydraulic Engineering, 2009, 135(11): 959-968.  苗峰显,郭志忠.灵敏度方法在电力系统分析与控制中的应用综述[J].继电器,2007,35(15):72-75.// Miao F X, Guo Z Z. A survey of sensitivity technique and its application in power systems analysis and control[J]. Relay, 2007, 35(15): 72-75. Jin Y J, Zhang Y M, Zhang Y L. Analysis of reliability and reliability sensitivity for machine components by mean-value first order saddlepoint approximation[J]. Journal of Mechanical Engineering, 2009, 45(12): 102-107.  王新刚,张义民,王宝艳.机械零部件的动态可靠性灵敏度分析[J].机械工程学报,2010,46(9):188-193.// Wang X G, Zhang Y M, Wang B Y. Dynamic reliability sensitivity analysis of mechanical components[J]. Journal of Mechanical Engineering, 2010, 46(9): 188-193. Abdollahipour A, Rahmananjed R. Sensitivity analysis of influencing parameters in cavern stability[J]. International Journal of Mining Science and Technology, 2012, 22(5): 707-710.  Zhou Y, Zhang Z, Zhong Q P. Improved reliability analysis method based on the failure assessment diagram[J]. Chinese Journal of Mechanical Engineering, 2012, 25(4): 832-837.  Hiskens I A, Pai M A. Trajectory sensitivity analysis of hybrid system[J]. IEEE Transactions on Circuits and Systems, 2000, 47(2): 204-220.  Liu W, Cao G, Zhai H B, et al. Sensitivity analysis and dynamic optimization design of supports' positions for engine pipelines[J]. Journal of Aerospace Power, 2012, 27(12): 2756-2762. Vilenus M J. The application of sensitivity analysis to electrohydraulic position control servos[J]. Journal of Dynamic Systems, Measurements and Control, 1983, 105(2): 77-82.  Farahat S, Ajam H. Sensitivity analysis of parameter changes in nonlinear hydraulic control systems[J]. International Journal of Engineering, 2005, 18(3): 239-252. 孔祥东,俞滨,权凌霄,等.四足仿生机器人液压驱动单元轨迹灵敏度分析[J].机械工程学报,2013,49(14):170-175.// Kong X D, Yu B, Quan L X, et al. Trajectory sensitivity analysis of hydraulic drive unit of quadruped bionic robot[J]. Journal of Mechanical Engineering, 2013, 49(14): 170-175. 张伟.四足机器人液压驱动单元负载模拟系统多余力抑制研究[D].秦皇岛:燕山大学,2013.// Zhang W. Study on the redundant force restraining of the load simulation system of quadruped robot's hydraulic drive unit[D]. Qinhuangdao: Yanshan University, 2013.