一种移动喷涂机器人的高效站位优化方法

An Efficient Base Position Optimization Method for Mobile Painting Robot

为喷涂飞机等大型工件,通常使用移动平台将6DOF喷涂机器人输送到不同站位进行喷涂.本文旨在为当前喷涂路径寻找使得机器人运动学性能最佳的站位.首先提出并利用外腕心的概念对喷涂机器人的空心手腕做球形近似,解决机器人不可解耦问题,并获得了其封闭形式的逆运动学解及位置、姿态和避奇异约束的具体表现形式.而后,基于约束和关节可用度指标,建立了关于站位的单点和连续喷涂任务代价函数,用以定量评估站位对机器人运动性能的影响.最后,通过内罚函数法最小化代价函数,对应的站位即为最佳站位.在平面、圆柱面和圆台面上的仿真实验结果验证了近似模型的准确性和此方法的有效性,且与现有方法相比,算法效率提升了百倍以上.

In order to paint huge workpieces such as aircrafts, 6DOF (degree of freedom) painting robots are always transported by a mobile platform to different base positions for working. This research aims at finding a base position for the current painting paths at which the painting robot gets best kinematic performance. Firstly, a concept of outer wrist center is proposed and used to make a spherical approximation of the hollow wrist, thereby overcoming the coupling problem. And closed-form inverse kinematics solutions of the robot and the concrete forms of position, orientation and singularity avoidance constraints are also obtained. Afterwards, based on the constraints and joint availability index, cost functions about base positions for single point task and continuous point task are established to evaluate the influence of the base position on the kinematics performance of painting robots quantitatively. At last, the internal penalty function method is used to minimize the cost function and then the corresponding base position is regarded as the desired one. Results of simulations on flat, cylindrical and conical surfaces demonstrate the accuracy of the approximation model and effectiveness of the proposed method. And the efficiency increases by a hundredfold comparing with the existed methods. © 2017, Science Press. All right reserved.