Department of Mechanical Engineering, École de Technologie Supérieure, Montreal, QC H3C 1K3, Canada.
Kinova Robotics, Boisbriand, QC J7H 1M7, Canada.
Sensors (Basel). 2022 Aug 26;22(17):6430. doi: 10.3390/s22176430.
Several industrial pick-and-place applications, such as collaborative assembly lines, rely on visual tracking of the parts. Recurrent occlusions are caused by the manipulator motion decrease line productivity and can provoke failures. This work provides a complete solution for maintaining the occlusion-free line of sight between a variable-pose camera and the object to be picked by a 6R manipulator that is not wrist-partitioned. We consider potential occlusions by the manipulator as well as the operator working at the assembly station. An actuated camera detects the object goal (part to pick) and keeps track of the operator. The approach consists of using the complete set of solutions obtained from the derivation of the univariate polynomial equation solution to the inverse kinematics (IK). Compared to numerical iterative solving methods, our strategy grants us a set of joint positions (posture) for each root of the equation from which we extract the best (minimizing the risks of occlusion). Our analytical-based method, integrating collision and occlusion avoidance optimizations, can contribute to greatly enhancing the efficiency and safety of collaborative assembly workstations. We validate our approach with simulations as well as with physical deployments on commercial hardware.
一些工业拾放应用，如协作装配线，依赖于零件的视觉跟踪。机械手运动引起的反复遮挡会降低生产线的效率，并可能引发故障。这项工作为维护具有可变姿态的相机与 6R 机械手（非腕部分区）所夹持的物体之间无遮挡视线提供了完整的解决方案。我们考虑了机械手以及在装配站工作的操作员的潜在遮挡。一个驱动相机检测物体目标（要拾取的部件）并跟踪操作员。该方法包括使用从单变量多项式方程求解逆运动学 (IK) 中获得的整套解决方案。与数值迭代求解方法相比，我们的策略为方程的每个根提供了一组关节位置（姿势），从中我们提取最佳的位置（最大程度降低遮挡的风险）。我们基于分析的方法，集成了碰撞和遮挡避免优化，可以极大地提高协作装配工作站的效率和安全性。我们通过模拟以及在商业硬件上的物理部署来验证我们的方法。
