Development Of A Parallel Weeding Robot For Lawns And Forages

Weeds in lawns and forages are important factors that affect their growth,the beauty of lawns and the quality of forages.Due to the wide planting area of lawns and forages,the control of weeds in lawns and forages is mainly through a wide range of spraying herbicide,which is fast.However,the waste of herbicide is serious,which affects the health of humans and animals.And large-sclae spraying of herbicide will make weeds resistant for the long term and increase the difficulty of subsequent weeding.Therefore,there is an urgent need for intelligent weeding equipment that can accurately apply pesticides to weeds in lawns and forages.There is a difference in height between lawns and forages,so the working space of the weeding robot should meet the requirements of weeding in lawns and forages.In order to ensure the efficiency of weeding,it is required that the executive mechanism of weeding robot has good dynamic performance.In addition,due to the different herbicidal spectrum of herbicides,corresponding herbicides were applied to monocotyledonous weeds and dicotyledonous weeds respectively.Therefore,the parallel mechanism was used as the executive mechanism of the weeding robot in this paper.The liquid conveying system of the robot adopts two kinds of herbicides.According to the types of weeds,the corresponding herbicides were accurately sprayed to improve the success rate of weeding robot.The main research contents are as follows:Firstly,the overall structure of weeding robot was designed.The weeding robot designed in this paper is suitable for the lawns or forages with few weeds.The weed identification method of weeding robot designed was introduced in this paper.The image below the robot is collected by the camera.When the weeds were identified,the sprayer only needs to move above the weeds and spray the corresponding herbicide.The mobile platform of the robot was a wheeled structure.The motor of the driving wheel of the robot was analyzed and selected.The parallel mechanism was selected as the actuator of the robot,and the given working space of the parallel mechanism was set as a cylinder with a diameter of 500 mm and a height of 250 mm.The genetic algorithm was used to solve the key dimensions of each component,and the motor of the driving arm was selected.According to the flow of herbicide,the liquid transportation system was analyzed and calculated.Since the herbicides have different herbicidal spectra,two kinds of herbicides were used in the liquid pesticide delivery system.Secondly,the kinematics of the parallel mechanism was analyzed.In order to understand the motion state of the parallel mechanism of the weeding robot,the kinematics equation of the parallel mechanism was created.The inverse kinematics solutions of the mechanism were calculated.The forward kinematics solution of the parallel mechanism was solved by geometric method and analytical method.Several possible singularity configurations of the parallel mechanism were analyzed according to the Jacobian matrix,so as to avoid the parallel mechanism moving to the singularity as far as possible in the design,so as to avoid uncontrollable situation.Then,the dynamics of the parallel mechanism was analyzed.The kinematic modeling was carried out by the Kane method,and the functional relations between the driving torque of each joint and the mass of each component,the position of the moving platform,the moving speed and the acceleration were calculated.Then the movement of the parallel mechanism was simulated by the software of ADAMS to simulate the force and torque of each rotating joint during the weeding operation of the parallel mechanism,so as to judge that the driving motor of the parallel mechanism meets the actual weeding requirements.The stress and strain analysis of the driving arm and the actuating arm of the parallel mechanism was carried out.The vibration characteristics of the actuating arm and the actuating arm were analyzed.The theoretical workspace of the parallel mechanism was drawn by MATLAB,and compared with the given workspace,it can be seen that the theoretical workspace of the robot includes the given workspace,so the robot can meet the requirements of weeding lawn and grass.Finally,according to the design and simulation results of the robot,a prototype of the weeding robot was made,and the actual working space of the prototype was measured,which proved the feasibility of the weeding robot in the lawn and forage.