In view of the problems of low spraying accuracy and extensive action execution in current orchard sprayers, this paper proposes a dual-arm apple tree canopy contour spraying arm with 6 degrees of freedom on one side. The overall structure and key components of the spraying arm are designed based on the external dimensions of standard apple trees in orchards. The static force conditions of the spraying arm at its limit position are analyzed using static equilibrium equations, yielding a maximum static force of 5 656.65 N. Based on the kinematic equations of the spraying arm, the working width on one side is 3 069 mm, the maximum working height is 5 191 mm, and the minimum height from the ground is 547 mm. The dynamic model of the spraying arm is established by the Lagrange equation method, and the functional relationship between the joint motion and the required driving forces is clarified. Under the motion characteristics defined by STEP5 function in ADAMS, the numerical calculation results of the dynamic model of joints O0 to O5 are compared with the ADAMS simulation results. The largest deviation occurs at 15 s, and the relative errors are 15.42%, 5.16%, 6.66%, 11.31%, 1.21%, and 13.56%, respectively, which confirm the validity of the dynamic model. Finally, a prototype of the contour spraying arm is built, and the contouring test results show that the average error of η is 19.79°, meeting the design requirements. These findings provide a basis for further research on motion control and trajectory planning of the multi-degree-of-freedom canopy contour spraying arms in orchards.

针对当前果园喷雾机喷施精度不高、动作执行粗放等问题，设计一种单侧具有6自由度的双摇臂式苹果树冠层仿形喷雾作业臂。根据标准苹果园的果树外形尺寸设计作业臂总体结构及关键零部件，基于静力学平衡方程分析作业臂在极限位置下的受力情况，求得作业臂受最大静力为5 656.65 N；基于作业臂运动学方程，分析获得作业臂单侧作业幅宽为3 069 mm，最大作业高度约为5 191 mm，最小离地高度约为547 mm；采用拉格朗日方程法建立作业臂动力学模型，明确作业臂各关节运动与所需驱动力的函数关系。在ADAMS中STEP5函数定义的运动特性下，将关节O0～O5的动力学模型数值计算结果与ADAMS仿真结果对比发现两结果在15 s处相差最大，其相对误差分别为15.42%、5.16%、6.66%、11.31%、1.21%、13.56%，验证动力学模型的正确性；搭建仿形作业臂样机，仿形试验结果表明，仿形平均误差η 为19.79°，满足设计要求，为果园多自由度冠层仿形作业臂的运动控制、轨迹规划等进一步研究提供基础。