Research Of Spray Boom’s Balance Control Based On V-ribbed Belt Drives

Based on current research, a spray boom balancing control system based on V-ribbed belt drive is designed for boom rotation control problem. The system consists of ultrasonic inspection system, PLC control system and ribbed drive system consists of three parts. In order to ensure transmission accuracy of v-ribbed belt drive system, a v-ribbed belt drive system mechanical model was established, and the influence factors of ultrasonic sensors detecting spray boom balance were studied experimentally. Finally,a step test was did for dynamic performance of the system,and determine the start threshold of the system; through field experiments to study the effect of control boom balance system, get the best parameters combination of the system.The main research work includes the following aspects:(1)The design of system of controlling spray boom balanceFor the problem of spray boom rotation,a spray boom balancing control system based on V-ribbed belt drive is designed in the existing sprayer. The detection principle of spray boom balancing, the structure of V-ribbed belt drive system and the structure of the control system are given, and according to the control structure to choose the main hardware, according to the control requirements to design the control program and control circuit, complete the design of spray boom balancing control system’s hardware and software.(2)Mechanical modeling of v-ribbed belt drive systemA mechanical model is established based on the structure parameters of v-ribbed belt drive system to study the effects of v-ribbed belt’s stiffness and damping factor for transmission accuracy, and access to the drive system transmission input and output relationship at different motor rotation speed. The main conclusions are: When the motor frequency is less than 6Hz, three installation positions corresponding to the V-ribbed belt, the relationship between motor and spray rotation angle were:41(28)20θθ,41(28)16θθ,41(28)12θθ.Provide the basis for the calculation of the pulse number in the stepper motor control.(3) Experimental Study of the effecting factors for the inspection of spray boom’s balanceDesign of ultrasonic sensor detection system, according to the working environment of ultrasonic sensor, to study the influences of different reflective surfaces, relative motion and beam angle of ultrasonic sensors for the inspection of spray boom’s balance. The main conclusions are:(1)Greater impact coarseness and flatness of crop canopy ranging. To reduce the impact of different crop canopy for the detection spray boom balance, selecting plane as a reflective ground of ultrasonic sensor. In this case, in order to prevent interference with the crop foliage for ultrasonic sensor, branch unit need to be installed in the position corresponding on spray boom,and to ensure that the ultrasonic wave can hit the ground.(2) In the speed range of sprayer, Maximum distance error is 0.689 cm of ultrasonic sensor,and the largest sample variance is 0.165 cm.So the impact of the relative motion of the ultrasonic sensor for the detection of boom’s balance is small.(3) When the ultrasonic sensor deflection angle is within the range of [-12 °,+12°] variation, ranging error is small. Deflection angle within the range of [±13°,±15°] variation, ranging error increases dramatically. However, due to the rotation angle of the spray boom is generally within the range[-5°, + 5°], so the effects of the ultrasonic sensor beam angle for the detection of boom’s balance is small.(4) Experimental study of the effect of controlling spray boom’s balanceDesign step test for dynamic performance research of control system of spray boom’s balance, and determine started threshold of the system. Design orthogonal test in field to research the effect of various system parameters for controlling spray boom’s balance. Specific conclusions are:(1)Control system of spray boom’s balance can effectively reduce the system’s stability influence by step excitation signals, and the best start threshold is?(28)cm5.(2)Orthogonal trials in field achieved spray boom’s control system can control spray boom balance, reduce boom rotation caused by the undulating ground.Over the three factors, including V-ribbed belt installation position, motor speed and preload in the ribbed, the motor speed is the most effective on spray boom balance’s control.With the optimum combination of factors,the spray boom angle can be controlled in range[-0.63 °, + 0.63 °].