The Design And Research Of Mechanism And Control System Of The Cucumber Harvesting Manipulator

In agricultural production,fruit and vegetable harvesting operation is the most time-consuming,labor-intensive sectors,basically rely on manual work and low degree of automation.Due to picking in complex environment,high labor intensity,and high labor requirements,harvesting costs accounted for thirty percent of the entire cost of fruits and vegetables.The rapid development of China’s urbanization,a large number of people engaged in agricultural production migrant workers,significantly reducing the agricultural labor force,agricultural production is toward large-scale,diversification,precise development.Research and development of intelligent agricultural robot and equipment can effectively alleviate the problem of the shortage of agricultural labor,but also improve the work efficiency,reduce production cost,improve the agricultural production environment,prevent prolonged labor,bad weather conditions,pesticides,fertilizers and other damage to workers,has important practical significance.For picking cucumber,after the analysis of the physical properties of cucumber,the mechanical structure of the cucumber picking manipulator was designed,and the control system was developed.According to existing laboratory conditions produced a picking manipulator prototype.The main work is as follows:(1)Access to a large number of documents,understanding of the current research situation of agricultural harvesting robot,existing problems.Through the understanding of the physical characteristics and the including the development trend and the growth environment of cucumber,designed the end effecter which have three fingers.These fingers using flexible material as the contact surface to prevent damage epidermis in the process of picking,and the FSR(force sensing register)is installed in the fingers,so that the end effecter has the function of force feedback.Based on the three degree of freedom manipulator in the laboratory,the mechanical structure of the cucumber picking manipulator was designed.(2)Using D-H method to establish the kinematics model of the picking manipulator.The kinematics analysis was carried out by using the analytical method,including the forward kinematics and inverse kinematics.In order to improve the working efficiency and stability of the picking manipulator,the trajectory planning of the picking manipulator is carried out in the joint space.According to the initial condition,analysis three kinds of interpolation methods,respectively cubic polynomial interpolation,cubic polynomial interpolation with intermediate points and quintic polynomial interpolation,and with examples verified this method used in this picking manipulator.(3)In view of the mechanical structure of the picking manipulator and the transmission mode of the joint,select the appropriate drive mechanism,and design the overall scheme of the control system.Control system adopts modular design,using PC and motion control card control mode to control the manipulator joints drive(AC servo motor),using PC and SCM to control the end effecter for flexible fingers to grab and release action.Complete control system of each module circuit design and welding,building control system hardware.On this basis,using Visual C++ software designed PC control interface,and using Keil C51 to prepare the MCU program,complete the design and development of control system software.(4)In order to test the degree of cooperation of each joint and the feasibility,performance test and simulation experiment of picking were carried out,to find out the existing problems and the part need to be improved.