| The liquid sample analyzer is a medical and biological experimental equipment,not only the stepper motor position requirements accuracy,but also a large amount of stepper motors involved in the simultaneous operation of the equipment.Therefore,high precision and multi-coordinated operation are difficult to realize for the liquid sample analysis instrument.Based on the research of domestic and foreign related fields,this paper presents a stepper motor control system based on FPGA for liquid sample automatic analyzer,which is a summary knowledge and organization of the upper computer,the database,the mechanical structure,the lower computer and the motor drive so on.This paper mainly studies the stepping motor control system in the liquid sample automatic analyzer.To ensure that more than one stepper motor precision and coordinated operation is the primary task of control system design.Based on the analysis of the motor running characteristics and the system structure,A new stepper motor control system is given:combined MCU,FPGA and incremental encoder to form a complete motion.The platform utilizes FSMC interface to realize the communication between MCU and FPGA,utilizes closed-loop PID control ensures motors operating exactly,any frequency dividing and pulse width modulation module converts the speed signal into different duty cycle PWM signals for stepping motor rotation,drive module utilizes LV8729 drive board and drive circuit based on LMD18200,that LMD18200 drive circuit is a self-designed a new type of stepper motor drive logic.Practice shows that utilize the new control method of FPGA + STM32 and the new drive method based on LMD18200 can effectively reduce the noise and the vibration in the running,which is better than most of the conventional stepper motor drive method. |
