Intermediate Desired Value Approach for Task Transition of Robots in Kinematic Control

The task-based control framework is well established for its ability to generate complex behavior in versatile robots. When executing multiple complex tasks, continuous and stable transition among these tasks is one of the most important issues. In this paper, the problem of task transition is discussed to achieve continuous transitions between arbitrary tasks effectively. Instead of modifying the control laws, the design of intermediate desired values to be realized by existing controllers is proposed. The proposed approach can deal with arbitrary task sets, with or without priorities, for insertion and removal, and with priority rearrangement for hierarchical sets of tasks. The solution is generic and can be used for any type of transition. Two examples of uses include a time-driven transition to execute a given task schedule and a transition depending on the robot configuration to perform joint-limit avoidance behaviors. The performance of the algorithm is verified in simulations and on a physical robot.