Integration Design And Experimental Research Of Manual And Automatic Integrated Steering Wheel

With the proposal of the concept of wisdom agriculture,because the traditional agricultural machinery does not have the driverless function,and there is a shortage of operators in harvest season,it becomes urgent to study the technology of automatic navigation and driving of agricultural machinery.As the executive link of automatic navigation system of agricultural machinery,the operability and adaptability of electric steering wheel will directly influence the accuracy of navigation control.Currently,there are some problems about electric steering wheel used in agricultural machinery,such as small torque,low steering accuracy,inability to switch between manual operation and automatic driving,etc.Therefore,designing a manual and automatic integrated steering wheel has very important scientific significance and practical application value for realizing autonomous navigation of agricultural vehicles.The main research work of this paper is as follows:An integrated design scheme of manual and automatic integrated steering wheel is put forward based on the design goal,the design of each working part of the transmission system is completed,the three-dimensional design of the steering wheel is completed by using Solidworks,and the key transmission parts are checked;A hardware system consisting of single chip microcomputer,manual automatic switch,angle detection of encoder and stepper motor driver is constructed;A test bed is designed to test the torque and rotational speed performance of the steering wheel.An angle control algorithm is designed in order to realize the tracking of the steering wheel to the target angle sent by the upper system.By analyzing the mathematical model and driving principle of stepper motor,combining PID algorithm with fuzzy algorithm,a fuzzy PID controller for steering wheel angle tracking is designed.Meanwhile,the stepper motor model,subdivision driving model,angle control algorithm model and actuator model are built in Matlab/Simulink,and the tracking simulation test of angle of steering wheel is carried out with different angle signals,so as to verify the rationality of angle control algorithm and the correctness of control model.Based on the Keil uVision5 platform,the discrete signal acquisition and filtering processing of the external manual automatic switch of steering wheel,the serial digital signal acquisition and protocol analysis of the absolute angular displacement encoder,serial digital signal acquisition of expected target angle of upper system and protocol analysis and program design of fuzzy PID controller are carried out.In order to realize the manual issuing and periodic reporting of various instructions on the steering wheel,the upper system is designed based on Labview platform.The performance test of the steering wheel on the self-designed test bed of steering wheel is carried out,the torque and rotation speed test of the steering wheel shows that the maximum output torque can reach 10N·m,and when the rotation speed is within 30r/min,the steering wheel has strong load capacity;The accuracy test of angle of steering wheel shows that the designed fuzzy PID controller can adjust the angle of steering wheel in real time,and the angle accuracy is 0.5%,the steering closed-loop test of the steering wheel shows that during the steering process of the steering wheel,the controller can quickly track the expected target angle on the premise of meeting the control precision requirements,and the maximum response time is within 1s,verifying the effectiveness of the designed fuzzy PID controller of steering wheel angle tracking.Through the performance test of the steering wheel,it is verified that the developed steering wheel meets the design requirements.