Research On The Control Technology Of The Actuating Mechanism Of The Push-and-Shake Camellia Fruit Picking Machine

The development of the camellia industry is inseparable from mechanized equipment,and the intelligentization of equipment is the key technology to realize the upgrade of the camellia industry to Agriculture 4.0.Therefore,it is very necessary and urgent to carry out research on mechanization,intelligent technology and equipment of Camellia fruit picking.This paper takes the push-shake camellia fruit picking machine independently developed by the project team as the research object,and uses the screw method and MATLAB/Simulink simulation method to study the intelligent control technology of the picking manipulator and the picking actuator.This paper mainly carries out the following researches:(1)The kinematic model of the picking manipulator was established based on the screw theory.And the Kane dynamics method was used to establish the dynamic model of the picking manipulator based on the analyze of its velocity Jacobian matrix.The control scheme of the electronic-hydraulic components of the picking machine was designed based on the improvement of the hydraulic schematic diagram of the picking manipulator.After that,the state space model of the machine-hydraulic coupling system was obtained on the basis of the he mathematical modeling of the servo-hydraulic system and the dynamic model of the picking manipulator.(2)A neural network fuzzy sliding mode variable structure adaptive controller was designed to control the camellia fruit picking manipulator by taking the machine-hydraulic coupling system of the picking manipulator as the controlled object.The method of trajectory tracking was used to simulate the neural network fuzzy sliding mode variable structure adaptive control controller with MATLAB/Simulink,which was compared and analyzed with the ordinary sliding mode variable structure controller.The simulation results show that the neural network fuzzy sliding mode variable structure adaptive controller has the characteristics of fast response,good robustness,and significantly reduces the chattering of the control system.The entire manipulator could completely follow the joint planning trajectory after 1.3s,the trajectory tracking error is within 0.054mm,the neural network approximation error is within 2.6,the inertial impact is controlled within 0.0005rad/mm,and the system has no obvious chattering,which meets the needs of the intelligent picking operation of the picking manipulator.(3)The hydraulic drive system was redesigned with an electro-hydraulic active control scheme,of which the core technology is the active pilot type electro-hydraulic proportional flow valve,on the basis of analyzing the working principle of the push-shake camellia fruit picking actuator.The state space model of the valve-controlled hydraulic system was derived based on mathematical model of the whole system.(4)A fuzzy neural network PID controller was designed to control the pushing and shaking motion of the output constant frequency by taking the valve-controlled hydraulic system of the picking actuator as the control object.And the fuzzy neural network PID controller of the hydraulic motor of the camellia fruit picking machine was built in the MATLAB/Simulink under three operating conditions:no-load condition,loading condition after running for 5s and start-up with load,which was compared with the general PID controller and fuzzy PID controller.The simulation results show that the fuzzy neural network PID controller has the characteristics of fast response,good stability and strong robustness under the no-load condition and the loading condition after running for 5s.The fuzzy neural network controller can respond to the output vibration within 0.5s,and can quickly reach a steady state within 3.3s under the load starting condition,which shows that this controller can well meet the operation requirements of the picker’s pushing and shaking hydraulic motor with a constant speed to ensure the movement frequency,so as to realize the mechanized picking operation of the camellia fruit falling off the branches.Finally,the field test of the picker was carried out to verify the effect of the control system designed in this paper.The test results show that the push-shake Camellia fruit picking manipulator could quickly and stably achieve the positioning and clamping of the target Camellia tree,as well as the whole pushing motion process was relatively stable,and the picking efficiency could reach 90.9%,and the drop rate of the flowers is 2.44%,which verifies that the control system can well meet the needs of the camellia fruit picking operation.The above controller provides technical support for controlling the flower drop rate of Camellia when picking the fruits.