Recursive Hierarchical Projection for Whole-Body Control with Task Priority Transition

Whole-body control (WBC) with task priority transition is an important technology for robots to switch multiple behaviors, change different objectives, and adapt to various environments. Many methods have solved the problem of control continuity in the priority transition process. However, they either increased the computation consumption or sacrificed the accuracy of tasks in practical application. In this work, we propose a Recursive Hierarchical Projection (RHP) matrix and introduce it in Hierarchical Quadratic Programming (HQP). This RHP-HQP scheme can form continuously changing hierarchical projection and regard the WBC problem with task priority transition as a unified formulation. This unified formulation can be smoothly transitioned without increasing computation consumption and solved without losing task accuracy. The comparative simulations of the reactive collision avoidance verify that this priority transition scheme can guarantee high computational efficiency and task accuracy.