The open loop gain and some parameters are different on the two moving directions of symmetric valve controlling asymmetric cylinder system. This difference leads to dynamic performance asymmetry on the two moving directions. The natural nonlinear and asymmetric system is difficult to control. The last three joints of P��-211 robot are controlled by symmetric valve controlling asymmetric cylinder system. To make the robot moving smoothly and improve the control precision, the control system must have proper compensation. After analyzing the asymmetric cylinder and taking the difference of protrusion and retraction into account, a new control algorithm, model reference self-tuning gain adaptive algorithm, was put forward. The new algorithm includes adaptive single neuron PID, model reference adaptive algorithm and self-tuning output gain. Simulations and experiments illustrate that the new control algorithm can compensate the asymmetric cylinder system, which is better than the command PID algorithm.
Vossoughi G,Donath M. Dynamic feedback linearization for electrohydraulically actuated control system [J].Dynamic System Measurement Control Transactions of ASME.1995,117(3):468-477
������.���طǶԳƸ�Һ�ŷ�ϵͳ�п��Ʋ����о�[J]. ������Ϣְҵ����ѧԺѧ��,2006, 1:39-42 Yue Donghai. The research on control strategy of valve controlled asymmetric cylinder electro-hydraulic servo system[J]. Journal of Changzhou Vocational Colkege of Information Technology, 2006, 1:39-42(in Chinese)
��ҵ��,�����.���طǶԳƵ�Һ�ŷ�ϵͳ���Ʋ����о�[J].�й���е����,1999, 10: 1172-1175 Zhang Yejian, Li Hongren. Study on control strategy for an electrohydraulic servo system with valve controlled asymmetric cylinder[J]. China Mechanical Engineering, 1999, 10:1172-1175(in Chinese)
Ҧ��,����,�Ź���.�ǶԳƸ��ŷ�ϵͳ�ı�����ģ������[J].Һѹ������,2004, 9:27-28 Yao Zhen, Yang Liu, Zhang Guoxian. Fuzzy control with variable region in servo system of unsymmetrical cylinder[J]. Chinese Hydraulics & Pneumatics, 2004, 9:27-28(in Chinese)
������,�����,�Ƽ.�ǶԳƷ����ƷǶԳƸ�ϵͳ�ľ�̬����̬���Է���[J].������Һѹ,2003, 1: 198-200 Wang Dongliang, Li Hongren, Li Chunping. Analysis of static and dynamic propertics of asymmetrical valve controlled asymmetrical cylinder[J]. Machine Tool & Hydraulics, 2003, 1: 198-200(in Chinese)
Niksefat N,Sepehri N.Fault tolerant control of electro-hydraulic servo positioning systems Proceedings of the 2001 American Control Conference. Arlington: IEEE Institute of Electrical and Electronics Engineers Incorporated, 2001, 4: 472-477
������,������.���طǶԳ�Һѹ������ģ̽��[J].��ɽ��е,1998, 7: 66-68 Wang Chuanli, Xu Xianliang. Model discussion of valve controlling asymmetric cylinder system[J]. Mining & Processing Equipment, 1998, 7: 66-68(in Chinese)