冗余驱动并联机构动力学模型TVC优化H∞鲁棒控制

H∞ Control of TVC Optimization Based on Redundant Actuated Parallel Manipulator Dynamics Modeling

摘要:

针对冗余驱动并联机构控制系统设计未结合动力学建模，未考虑伺服阀动、静态特性等问题，基于第二类Lagrange方程和流体力学动力学知识，对动平台及液压系统中机械、液压系统建模，建立电液伺服系统五阶传递函数模型，通过主导能量最优模型将其降为三阶模型。以此为控制对象提出了基于三矢量控制（Three vector control，TVC）反馈优化的H∞鲁棒控制策略（TVC-ROB），并与TVC前馈反馈控制、TVC反馈优化的模糊自适应PID控制（TVC-FAPID）两种控制策略在阶跃信号、线性扫频、实际武广谱路谱等进行对比分析。结果表明，TVC反馈的提出有效拓展了系统频宽，且提高液压系统阻尼比和固有频率，因此TVC-ROB在高频跟踪性能上改善较为明显，其位移误差百分比仅为1.26%，且引入的H∞鲁棒控制提高了系统抗扰、抗噪性能。

Abstract:

Aiming at the problem that the control system of redundant driven parallel mechanism is not combined with dynamic modeling and the dynamic and static characteristics of servo valve are not considered in the design of the control system, a fifthorder transfer function model of electrohydraulic servo system was presented based on Lagrange equation of the second kind and hydrodynamics to model the mechanical and hydraulic systems of the moving platform and hydraulic system. The dominant energy optimal model was reduced to a three order model. Reducing order to more easily processed order was convenient for subsequent dynamic control. A H∞ robust control strategy based on TVC feedback optimization was proposed for the control object. It was further compared with TVC control and TVC-FAPID in step signal, linear sweep and actual broadspectrum. The comparison showed that the proposed TVC feedback effectively expanded the systems bandwidth and improved the damping ratio and natural frequency of the hydraulic system. So that H∞ robust controller can compensate the phase lag of high frequency signal. Therefore, the TVC-ROB improved the tracking performance of the highfrequency system obviously, and the displacement error percentage was only 1.26%. The H∞ control was introduced to improve the antidisturbance and antinoise performance of the system. In the high frequency section, the control energy loudness of TVC-ROB and TVC-FAPID strategies was much lower than that of TVC control, which tended to be stable. In the low frequency band, the parameters tuning of TVC control strategy was simple and easy to implement. So the TVC control strategy was often applied in engineering field. The research results had a strong guiding significance and reference value for the design of controller.