The Sun Tracker Design Based On ARM

Based on the mathematics models of two-phase hybrid stepping motor,using the stepper motor drive control principle,connected with subdivided control thesis,designed a model of subdividing control driving system based on STM32F407.Research of the two axis stepper motor coordination control to realize real-time tracking of the sun and made a research for the system open loop and the position of the closed loop PID control.Firstly,we studied the methods to control the sun tracking system,analyzed the control precision of all kinds of methods.Then we introduced and selected the method of sun-rail track based on the celestial sphere model and coordinate system.Detailed the calculation process of the altitude Angle and azimuth,included the high accuracy tracking the working principle of four quadrant photoelectric detector of the sun.What's more,we analyzed the control train of thought by sun-rail track method combining coarse four quadrant detector of fine adjustment.On the hardware design,we firstly introduced the internal structure and working principle of stepper motor and start-stop speed control curve.Then introduced the structure,working principle of stepper motor drives and based on the principle of "subdividing-control" micro step distance control.This paper introduces the system control block diagram with the main control chip STM32F407 as the core.And the working principle of four quadrant photoelectric detector,algorithm and circuit design;GPS module circuit design and the communication protocol.On the control strategy,On the basis of the known preliminary installation location,analysis of the current position from the previous moment position difference in equal time intervals,then step motor rotation Angle are calculated,this is the open-loop control,which implemented a rough adjustment.Then through four quadrant photoelectric detector stepper motor position feedback,the PID gain high precision position closed-loop control.Finally,on the design of experimental platform,the experiment proved the feasibility of the subdividing-control of the stepping motor controller,the simulation of the system response curves illustrates the system "open loop control and closed loop PID control" control has higher control precision.Motor runs smoothly and satisfies the requirement of engineering practice.