Design And Control Of Cable-Driven Parallel Mechanism In Electron Optic Tracking System

This thesis investigates a novel composite axis Electron Optical Tracking System(EOTS),which adopts a Cable-Driven Parallel Mechanism(CDPM)to control the secondary tracking structure.The proposed solution addresses the issue of limited workspace for the fast steering mirror in traditional composite axis ETOS and offers advantages such as high tracking speed and a large workspace,enabling the threedimensional position tracking of fast-moving targets.This study focuses on the key technology of the CDPM that controls the secondary tube.In this thesis,the key technologies for the design and control of the CDPM in this scheme are investigated.First,the basic configuration of the CDPM is determined based on the vector closed principle.The rotation angles of the secondary tube in two degrees of freedom can be precisely measured by designing a shaft structure.The system’s kinematic equations are described using the angles as a set of generalized coordinate.Considering the influence of internal forces in the system,the dynamic equations of the system are derived using the Lagrangian energy method.A tension distribution solution based on preload force is given using the generalized inverse of the structural matrix.Next,simulation verification and analysis are performed using a virtual prototype model built in ADAMS to validate the system’s mathematical model.Based on the analysis of the structural matrix,the steps for numerically solving the workspace of the CDPM are derived.The influence of relevant structural and mechanical parameters on the distribution of the workspace is discussed.Subsequently,the dynamic control strategy of the system is designed based on the dynamic analysis,utilizing the trajectory planning in the generalized coordinate system.The coupling terms in the system are also considered part of the total disturbance,then a Linear Active Disturbance Rejection Controller(LADRC)is designed to observe and compensate for the total disturbance,achieving decoupled control of the system in two degrees of freedom,and the stability of the controller is analyzed.The feasibility of the control strategy is verified through joint simulation in ADAMS and MATLAB,and the results show that the designed controller has good robustness against external disturbances and internal parameter distortions.Finally,the mechanical structure of the experimental prototype and the implementation of the control structure are completed.Key components are selected and designed,and a control system with FPGA as the main controller and DSP as the auxiliary is adopted.The control programs for both devices are designed.After calibrating some components,point-to-point control experiments and continuous trajectory motion experiments are performed to verify the feasibility of the entire system solution.