With the goal of enabling the exploitation of impacts in robotic manipulation, a new framework is presented for control of robotic manipulators that are tasked to execute nominally simultaneous impacts. In this framework, we employ tracking of time-invariant reference vector fields corresponding to the ante- and post-impact motion, increasing its applicability over similar conventional tracking control approaches. The ante- and post-impact references are coupled through a rigid impact map, and are extended to overlap around the area where the impact is expected to take place, such that the reference corresponding to the actual contact state of the robot can always be followed. As a sequence of impacts at the different contact points will typically occur, resulting in uncertainty of the contact mode and unreliable velocity measurements, a new interim control mode catered towards time-invariant references is formulated. In this mode, a position feedback signal is derived from the ante-impact velocity reference, which is used to enforce sustained contact in all contact points without using velocity feedback. With an eye towards real implementation, the approach is formulated using a QP control framework, and is validated using numerical simulations both on a rigid robot with a hard inelastic contact model and on a realistic robot model with flexible joints and compliant partially elastic contact model.
翻译:为了能够利用机器人操纵的影响,提出了一个新的框架,用于控制受命执行名义上同时撞击的机器人操纵器。在这个框架内,我们采用跟踪与先变和后影响运动相对应的时变参考矢量字段,增加其对类似常规跟踪控制方法的适用性。先变和后影响参量通过硬性撞击图加以结合,并扩大到影响预期发生影响的区域周围的重叠,从而可以始终遵循与机器人实际接触状态相对应的参考。由于不同联络点通常会发生一系列影响,导致接触模式的不确定性和不可靠的速度测量,我们制定了一种针对时间-异变参考物的新的临时控制模式。在这一模式中,位置反馈信号来自先变速度参考,用于在不使用速度反馈的情况下在所有接触点执行持续接触。为了真正执行,该方法采用QP控制框架,并使用具有硬性弹性联合接触模式的硬性机器人模拟和部分符合现实性联合接触模式的机器人进行验证。