Research On Adaptive Steady Attitude Control Of Stepping Pan-Tilt-Zoom

The PTZ(Pan-Tilt-Zoom)is widely used in many fields and occasions,due to its ability to carry kinds of instruments and equipment to expand and extend the workspace of them,and to compensate the impact of various disturbances generated by the devices,which carried PTZ,during the course of working.The content this paper researched was the Stepping PTZ(SPTZ)on adaptive steady attitude with the ability to high-speed response considering the dynamic stability,and a complete 2-DOF SPTZ control system was designed and implemented.The brief details list as following:(1)The hardware of this PTZ control system consists of ring frame mechanical structure,two-phase hybrid stepper motors and subdivision drivers,attitude sensor MPU6050 and development board MINI2440 with main controller S3C2440.For software,the environment of ARM-Linux cross-compiler was established on PC,embedded Linux operating system was built on MINI2440,then the implementation of PTZ control software and the program to drive stepper motor was based on this environment.(2)A coordinate system suitable for the PTZ was established,and the related methods for obtaining more stable and accurate attitude information were deduced.And for verifying the feasibility of those methods,to calculate them after original data was collected by main controller from MPU6050 with the interface I2C.(3)The mathematical model of two-phase hybrid stepper motor was derived from the voltage balance equation and the motion balance equation.In order to meet the requirement for wide frequency range of stepper motor,a frequent frequency conversion pulse modulation technology was proposed,which has the advantages of free duty cycle and free from frequency limitation.The driver of motor was realized,and the process of calling the driver and generating pulse signal in Linux was explored.The advantages and disadvantages of the control processes described by the three control curves were compared.The pulse situation of the motor in actual control under the premise of using the curve control process was analyzed,and the countermeasures for the possible interference in the control process were put forward.(4)The variable universe fuzzy adaptive PID control algorithm was studied deeply,and the functions,principles and implementation of each component were elaborated.The simulation experiment was carried out with the tool of MATLAB/SIMULINK,and its scaling factor was studied.The advantages and disadvantages of variable universe fuzzy adaptive PID control algorithm and traditional PID control algorithm were compared.On the basis of the research above,three control strategies were designed.The relationship between the algorithm and the control process,the control parameters involved and their determination methods were described in detail.The final control curve scheme of PTZ was determined by the actual control results.Finally,the system integration test was made,it shows that the SPTZ achieved in this paper meets the requirements of high-speed response,smooth and stable operation process,ability of adaptive attitude,and good accuracy of position.