Research On Motion Control Of Spherical Two-Degree-of-Freedom Parallel Pointing Mechanism

The Spherical two-degree-of-freedom parallel pointing mechanism is a kind of parallel mechanism that can complete the spatial positioning function,and can realize the target search,tracking,positioning,pointing and other functions.It has a good prospect of application and development in satellite communication,deep space exploration,space observation and other fields.Based on the spherical two degrees of freedom to parallel mechanism as the research object,from the trajectory planning,control mode,control strategy and other aspects are studied,the idea of open mode control to the whole control system development,building based on "PC + motion control card" control system,fuzzy control algorithm improve the control accuracy of stepping driving system,and the related control experiment was carried out.Firstly,according to the model of spherical two-degree-of-freedom parallel pointing mechanism,the inverse kinematics equation applied to motion control is solved.The motion path planning and trajectory planning of the mechanism are carried out in the working space of the mechanism,and it is verified by MATLAB and Adams joint simulation.Secondly,according to the characteristics of spherical two-degree-of-freedom parallel pointing mechanism,the structure level,control strategy and control algorithm of the control system were determined,and the mechanism control system was built,including the selection of components,electrical system design and control cabinet design.After preliminary debugging basic motion control,on the basis of implementation mechanism to ensure maximum amount of default angular displacement control of step motor,improve the accuracy and reliability of system,dynamic performance and robustness,and improve the stepping motor is easy to lose the step,operating problems such as instability,fuzzy control method,the step motor control model was established based on Simulink simulation software and the model of fuzzy controller,the institutions for control system simulation,the design is verified by the fuzzy PID controller in the control of steppingdriving system,the traditional control,compared with the response time is short,and the advantages of small steady-state error,It is effective to improve the control precision of the stepping motor,and can improve the control precision of the mechanism to a certain extent.Finally,the software structure of the motion control system of spherical two-degree-of-freedom parallel pointing mechanism is analyzed.Combined with the control card functions and control requirements,the hierarchical structure of control is planned.The upper computer software is developed with relevant development tools,and the mechanism is studied experimentally.