Design And Research Of Control System For Two-axis Pan-tilt-zoom

As the carrier of optoelectronic integration eqruipment,the pan-tilt-zoom is used to carry special equipment such as cameras to expand the freedom and workspace of the equipment.The pan-tilt-zoom is mainly divided into two parts:the platform and the control system.The disadvantages of traditional corntrol system of pan-tilt-zoom,such as large volume,limited processing speed,poor anti-interference ability and low steady-state accuracy,seriously restrict the development of pan-tilt-zoom.The research object of this paper is a two-axis pan-tilt-zoom.The purpose of this paper is to design a set of pan-tilt-zoom control system with high accuracy,fast response and good stability to meet the design requirements.Firstly,the basic rechanical structures of U-shaped platform,reducer drive and permanent magnet synchronous pan-tilt-zoom motor drive are defined.The mathematical model of the pan-tilt-zoom motor based on synchronous rotating coordinate system is constructed,and the three-closed-loop control structure arid vector control strategy of the system are determined.Secondly,in the design of control algorithm for three-phase voltage inverters,this paper compares the conventional SPWM algorithm,the SPWM algorithm based on third harmonic injection,the SPWM algorithm based on mean zero-sequence component injection,the SPWM algorithm based on extreme zero-sequence component in jection,the SPWM algorithm based on alternating zero-sequence component injection and the SVPWM algorithm in detail to determine the design of control algorithm for three-phase voltage inverters.In the design of current loop,the hysteresis control law and PI control law are compared in detail to determine the design of PI current loop controller.In the design of speed loop,this paper compares PI control law with sliding mode variable structure control law in detail,and determines the design of sliding mode variable structure speed loop controller In the design of position loop,this paper compares the PID control law,sliding mode variable structure control law and fuzzy Self-tuning PID control law in detail,and determines the design of the system fuzzy Self-tuning PID position loop controller.Finally,this paper designs and implements the whole hardware circuit and control software of the system based on modularization idea,completes the control algorithm of SVPWM three-phase voltage inverters and the program realization of each closed-loop controller,and realizes the specific functions of the system by combining the hardware circuit.Through experiments,it is proved that the two-axis pan-tilt-zoom control system designed in this paper has good dynamic and static performance and meets the requirements of relevant design indicators.It has extremely important theoretical value and reference significance for the design of pan-tilt-zoom in security and other fields.