Abstract:Directing at the problems that domestic sugarcane harvester header height adjustment and nonautomatic control, a servo control system for sugarcane header height was designed. The servo control system mainly consisted of a self-weight swinging profiling mechanism, STM32 controller, displacement sensor, upper computer module, keypad module, solenoid valve drive module, etc. The self-weight swinging profiling mechanism consisted of a ground contact, a connection sleeve, a left fixed connection plate, a frame, a right fixed connection plate, an angle sensor, etc. To address the problem that the harvester may cause impact or destroy the profiling mechanism when performing the reversing operation, ADAMS dynamics simulation software was utilized to obtain the vertical height and force variation of the profiling mechanism, and complete the optimization design of the tail end of the profiling mechanism. The simulation tests showed that when the radius of the tail end was 105mm, the maximum collision force of the ground on the profiling mechanism was equal to 1976N less than the permissible bending strength of 45 steel, which met the design requirements of the profiling mechanism. It was also verified that the profiling mechanism can adhere to the ground. To study the relationship model between the height of the harvester's cutting table and the signals collected by the profiling mechanism, and design a PID algorithm for cutting table height control. The PID control algorithm was optimized by using Matlab/Simulink software. After tuning the calculation optimization, when the proportional coefficient Kp was 0.41, the integral coefficient Ki was 0.76 and the differential coefficient Kd was 0.009, the PID controller met the requirements of the servo control system. The profiling mechanism sent the detected terrain height data to the STM32 control unit, and after analysis and processing, the hydraulic actuators were driven to control the lifting and lowering of the cutting table. After completing the design of the cutting table servocontrol system, it was installed on a 4GZQ130-A sugarcane harvester for functional tests. The driver started the machine, activated the cutting table servo control system for harvesting, set the cutting height, harvested three monopoles, observed the stubble height at each harvest, recorded the test data, measured the distance from the ground to the cut point of the cane and calculated the head breakage rate. The test results showed that after the 4GZQ130-A sugarcane harvester was fitted with a cutting table follower control system, the stubble height deviated from the preset stubble height within 20mm, an average head breakage rate was 21%. In comparison with the manually controlled harvesting trials, the average head breakage rate was reduced by 18.5 percenage points. The harvesters performance was further improved and the overall performance of the cutting table follower control system met the design and use requirements.
