Many robot manipulation tasks require the robot to make and break contact with objects and surfaces. The dynamics of such changing-contact robot manipulation tasks are discontinuous when contact is made or broken, and continuous elsewhere. These discontinuities make it difficult to construct and use a single dynamics model or control strategy for any such task. We present a framework for smooth dynamics and control of such changing-contact manipulation tasks. For any given target motion trajectory, the framework incrementally improves its prediction of when contacts will occur. This prediction and a model relating approach velocity to impact force modify the velocity profile of the motion sequence such that it is $C^\infty$ smooth, and help achieve a desired force on impact. We implement this framework by building on our hybrid force-motion variable impedance controller for continuous contact tasks. We experimentally evaluate our framework in the illustrative context of sliding tasks involving multiple contact changes with transitions between surfaces of different properties.
翻译:许多机器人操作任务要求机器人与对象和表面进行接触和断开接触。 这种变化中的机器人操作任务的动态在接触发生或中断时是不连续的,在其他地方是连续的。 这些不连续使得很难为任何此类任务构建和使用单一的动态模型或控制战略。 我们为这种变化中的接触操纵任务提供了一个顺利动态和控制框架。 对于任何特定的目标运动轨迹, 框架逐步改进了对何时会发生接触的预测。 这种预测和与撞击力有关的方法速度的模型改变了运动序列速度的轮廓, 使动作顺序的速度变得很顺利, 帮助实现预期的撞击力。 我们执行这个框架, 利用我们混合的动动动阻力控制器进行连续接触任务。 我们实验性地评估我们框架的轮动任务的说明性背景, 涉及不同属性表面之间的交替发生多重接触变化。