基于复合粒子群自适应液压伺服系统力跟踪控制与试验

Force tracking control and test of adaptive hydraulic servo system based on composite particle swarm optimization

为提高液压伺服系统力跟踪控制性能,针对不同环境模型及变期望力条件下,液压伺服系统末端位置力跟踪存在稳态误差及动态特性差问题,提出一种复合粒子群自适应阻抗控制策略。在建立液压伺服系统数学模型和阻抗模型基础上,根据环境刚度及力偏差,采用模糊算法确定阻抗参数范围,结合莱维飞行粒子群快速通过局部与全局搜索确定不同环境刚度下的阻抗参数,采用三次样条插值拟合阻抗参数随环境刚度变化方程;分析末端位置力跟踪稳态误差原因及并建立数学模型,根据末端位置力及当前末端位置,利用自适应算法估计环境刚度与环境位置,对期望位置补偿并选择阻抗参数。通过Matlab-Adams虚拟样机仿真,验证复合粒子群自适应阻抗算法对液压伺服系统力跟踪有效性。二连杆串联机构台架试验结果表明,采用复合粒子群自适应阻抗策略液压伺服系统力跟踪控制,末端位置稳态误差范围0~1,在期望力发生变化时,力跟踪动态性能良好。研究为液压伺服驱动足式农业移动平台及大型农业采摘机械臂末端位置力控制设计提供参考。

In order to improve the performance of the force tracking control of the hydraulic servo system, the terminal position force tracking of the hydraulic servo system had the problem of steady state error and poor dynamic characteristic under the conditions of different environment models and variable expectation forces, an adaptive impedance control strategy for composite particle swarm optimization was proposed. Based on establishing the mathematical model of hydraulic servo system and the impedance model, according to the environment stiffness and force deviation, using fuzzy algorithm to determine the range of impedance parameters, combined with the improved Particle Swarm Optimization based on Levy Flights quickly through the local and global search to found the impedance parameters under different environment stiffness, the three spline interpolation was used to fit the equation of the impedance parameters with the change of the environmental stiffness; then, the mathematical model was established on the basis of the analysis of the cause of the steady error caused by the force tracking of the terminal position of the hydraulic servo system, according to the terminal position force and the current end position, the environment stiffness and environment location were estimated by adaptive algorithm, in order to compensate for desired position and select impedance parameters. Through the simulation of Matlab-Adams virtual prototype, the effectiveness of impedance algorithm of the composite particle swarm optimization adaptive for the force tracking of the hydraulic servo system was verified. The results of bench test of two link series mechanism showed that the force tracking control of hydraulic servo system using impedance strategy of composite particle swarm adaptive enables the terminal position to track the expected force in real time and accurately,and the steady-state error range was 0-1. The dynamic performance of the force tracking was fine when the expectation of the force changed in the current period. It provided a reference for the agricultural mobile platform of foot type with hydraulic servo system as a driving device and the end position force control design of the large agricultural picking arm.