Design And Research Of Electrodynamic Five-degree-of-freedom Robotic Arms For Hedge Trimming

With the advancement of “green city” and “forest city” campaigns,landscaping maintenance has become increasingly demanding and hedge trimming has become a key area.To address the current problems in landscaping maintenance like the low utilization rate and poor adaptability of machinery,high labor intensity,and unfavorable general performance,it is of great significance to develop efficient and energy-saving automated hedge-trimming equipment.Taking electrodynamic five-degree-of-freedom(5-DOF)robotic arms for hedge trimming as the research object,this research is carried out from four aspects of structural design,kinematics analysis,terminal trajectory planning,and control system design—and is specified as follows:(1)Based on the operation requirements of hedge trimming,the structural design of electrodynamic 5-DOF robotic arms for hedge trimming was conducted through selective verification from three aspects: structure type,freedom degree,and driving mode.According to the trimming task,the robotic arm’s limit position was analyzed,the motion range of each joint of the arm and the length parameters of each rod were determined,and the threedimensional model of the hedge-trimming robotic arm was established using Solid Works;the finite element analysis of its structure is carried out by the static structure module of ANSYS Workbench software to prove the rationality of its structural design.(2)Kinematics analysis was performed on hedge-trimming robotic arms.With the improved D-H parameter method,the kinematic model of the hedge-trimming robotic arm was established and deduced with forward and inverse kinematics,yielding the forward kinematics equation and the inverse solution;with Robotics Toolbox in Matlab,the kinematics model of the hedge-trimming robotic arm was established to verify the correctness of the derivation results of forward and backward kinematics.With the Monte Carlo method for numerical analysis,the working space of the hedge-trimming robotic arm was analyzed,and through program coding with Matlab,the two-dimensional and threedimensional cloud maps of the working space were generated.(3)The trajectory planning of the hedge-trimming robotic arm was carried out.By comparing the trajectory planning of the robotic arm under four interpolation methods in Cartesian space and joint space,the quintic polynomial interpolation algorithm in joint space planning was chosen to analyze the trajectory planning of the hedge-trimming robotic arm.The model of the hedge-trimming robotic arm was established with Matlab and its trajectory planning program was written with quintic polynomial interpolation.Also,the trajectory planning and simulation analysis of the hedge-trimming robotic arm under two working conditions were performed respectively,and the feasibility of the trajectory planning was theoretically verified with the quintic polynomial interpolation algorithm in joint space.(4)The control system of the hedge-trimming robotic arm was designed.The control system of the hedge-trimming robotic arm was designed with Matlab and controlled through the digital PID controller.By developing a co-simulation platform of Adams and Matlab Simulink for the hedge-trimming robotic arm,it was simulated by both of the platforms.Eventually,the correctness and rationality of the PID control system for the hedge-trimming robotic arm were verified by the step response change curve of each joint and the motion process in Adams.The prototype was processed and verified by experiments to ensure the reliability of the hedge trimmer manipulator.The research on the structural design,kinematics,terminal trajectory,and control system of the electrodynamic 5-DOF robotic arm for hedge trimming lays a theoretical foundation for the research and development of automated hedge-trimming equipment.