果园绿篱修剪机械手的设计与研究

Design and research of orchard hedge trimmer manipulator

为了解决果园绿篱修剪工具自动化程度低、修剪作业劳动强度大、工作效率低等问题,根据果园绿篱修剪作业要求,设计了一款实用的由液压驱动的四自由度修剪机械手,并确定了机械手各关节的运动范围。首先,基于标准的D-H参数法建立了机械手各连杆的坐标系,对机械手的正、逆运动学进行了求解;然后,利用MATLAB Robotics Toolbox建立了机械手运动学模型,对机械手正、逆运动学,机械手修剪绿篱顶面、侧面时各关节的运动轨迹,机械手各关节的角位移、角速度和角加速度曲线进行了仿真验证;之后,采用Monte Carlo法对机械手的工作空间进行了仿真分析,得到了机械手工作空间三维云图及平面云图;最后,试制实物样机进行了实验验证。研究结果表明:机械手正、逆运动学求解正确,所设计的机械手末端执行器完全能够到达所需修剪的目标位置。修剪机样机实验效果与预期相符,机械手工作时各关节运行平稳、修剪效率高、效果良好,能够满足对中、高绿篱自动修剪的要求,大大降低了修剪作业的劳动强度。

In order to solve the issue of less automated orchard hedge trimming tools,high labor intensity of trimming operations,and low work efficiency,a practical hydraulic driven four-degree-of-freedom trimming manipulator was designed according to the requirements for orchard hedge trimming operations,and the motion range of each joint was determined.Based on the standard D-H parameter method,the coordinate systems of each link of the manipulator were established,and the forward and inverse kinematics calculations of the manipulator were completed.A kinematic model of the manipulator was established using the MATLAB Robotics Toolbox,and the forward and inverse kinematics of the manipulator,as well as the motion trajectories of each joint,and the angular displacement curves,angular velocity curves,and angular acceleration curves of each joint of the manipulator during the trimming of the top and side of the hedge were simulated and verified.In addition,the workspace of the manipulator was simulated and analyzed by using the Monte Carlo method,thus 3D and planar cloud images of the workspace were calculated.Finally,an experimental prototype was produced for trimming testing.The research results show that the correctness of the forward and inverse kinematics solutions of the manipulator are verified,and the designed end effector of the manipulator can fully reach the desired trimming target position.The experimental results of the trimming machine prototype are consistent with expectations.The joints of the manipulator move smoothly during operation,with high trimming efficiency and good results,which can meet the automatic trimming requirements for medium and high hedge,and greatly reduce the labor intensity of trimming operations.