| Underactuated systems are regarded as a class of systems in which the dimension of independent control inputs is fewer than the dimension of freedom,and are very common in the field of control research.The underactuated system may be divided into the directly controlled subsystem and the indirectly controlled subsystem according to whether the system input directly affects the system state.The directly controlled subsystem possesses itself controller for reaching the control target,while the indirectly controlled subsystem change its state only by through the coupling relationship with the directly controlled subsystem.During tracking control of the underactuated system,since the indirectly controlled subsystem is not under direct control,it is considered in this paper that the requirement for the tracking reference value of the indirectly controlled subsystem is transferred to the requirement for the tracking reference value of the directly controlled subsystem through the internal linkage of the system.Then the reference values of tracking target are not independent but related to each other.In this paper,the underactuated system is considered as the research object,the appropriate control schemes are proposed to force the underactuated system tracking the reference goal based on the condition that the reference tracking targets are related to each other.The paper may be summarized as follows:In the first chapter,the main background and significance considered in this paper are briefly described,the underactuated system and its application status and development trend are introduced,and some common underactuated system models are listed.The second chapter is the inspiration chapter of the main research method introduced in this paper.Through the analysis of the vector control strategy of the permanent magnet synchronous motor(PMSM)in the case of the direct axis current_di?0,it is considered that the tracking control targets have a certain relationship with each other in the tracking control of current,voltage,and rotating speed.Therefore,a tracking control problem for a class of underactuated systems based on associated tracking targets is proposed.In the third chapter,for the tracking control problem of a class of underactuated systems based on associated tracking target,we do further analysis and study,and give a unified tracking control design method,which is verified by the numerical simulation experiment of PMSM and ball-beam system.At the same time,the robustness of the controller is simulated and analyzed.In the fourth chapter,under the condition that there is uncertain interference in the directly controlled subsystem,the tracking control problem of the underactuated system based on the associated tracking target is further discussed,and the controller with the adaptive law is designed to carry out the tracking control.At the same time,the numerical simulation results of tracking control of PMSM and ball-beam system verifies the effectiveness of the control method.The fifth chapter summarizes the full text,and the follow-up research and work of tracking control problem of the underactuated system are explained based on the associated tracking target. |
