Automatic Steering System Design And Optimization For The Intelligent Warehouse Stacking Forklift

Automatic steering control technology is that the steering control systemaccording to the steering command that send by the host computer tocontrol the steering actuator, and then to drive the steering wheel to complete the steering action, and so as to realize the control of the automatic steering process. As one of the key technologies of the intelligent vehicle, the performance of its implementation directly determines the accuracy and stability of the automatic navigation vehicle. In this paper, the automatic steering control system of the intelligent warehouse stacking forklift is designed using the electric car as the development platform.The main research contents of this paper are as follows:1)Through the analysis of the research status of the automatic steering system on both domestic and foreign, and combined with the characteristics of the intelligent storage stacking forklift, a design scheme of the control system by using motor is proposed.With STC89C52 RC MCU as the core of the control system, and use the PD control algorithm as the core algorithm of the steeringsystem.The design of the actuator is in principle that not to change the original steering system. Using the stepper motor as drive motor of the steering system,the torque of the stepping motor is transferred to the steering shaft ofthe electric car through the synchronous belt drive.Meanwhile install an absolute value encoder that measure the real-time steering Angle of the steering wheel,so as to realize the closed-loop control of the steering drive motor, and finally realizes theautomation control of the electric car steering process.2)According to the design scheme of the actuator,hadmade some related research and design work, mainly including the selection of the stepper motor, the design and calculation of the synchronous belt transmission and so on.And complete the installation of the steeringactuator and the sensoraccording to the structure characteristics of thesteering systemof the electric car.3)Complete the design work of the hardware control circuit according to the design of steering actuator of the automatic steering control system. Thedesign work mainly including master SCM smallest system, stepping motor driver module, liquid crystal display module, the angular displacement sensor circuit, etc. And also design the software of the steering control system on the basis of the steering control system hardware circuit.It mainly including the driver procedure of the angular displacement signal acquisition and processing procedures, the driver procedure of the stepper motor driver, the driver procedure of the serial communication program and the driver procedure of the PD control algorithm, etc.4)In order to verify the design of the automatic steering system, some experiments were carried out.The test content mainly includes the calibration test of the encoder, the test of stepper motor performance and the coefficient of PD control algorithm. Finally, in order to verify whether the automatic steering system designed meets the design goal, the closed-loop test is carried out for the small angle and large angle steering.According to the fluctuations of the system near the target angle, the dead zone is added in the program, the range of dead zone is [-0.2,0.2]. The experimental results show that the automatic steering system designed can meets the goal of this research institute set.