Continuous Reachability Task Transition Using Control Barrier Functions

Published in International Federation of Automatic Control (IFAC), 2020

Recommended citation: M. Srinivasan, C. Santoyo, S. Coogan "Continuous Reachability Task Transition Using Control Barrier Functions," International Federation of Automatic Control (IFAC) , 2020.

In this paper, a method to achieve smooth transition between sequential reachability tasks for a continuous time mobile robotic system is presented. Control barrier functions (CBFs) provide formal guarantees of forward invariance of safe sets and finite-time reachability and are able to enforce task execution. Control barrier functions used in quadratic programs result in the implementation of controllers with real-time performance guarantees. Existing approaches for multi-objective task execution using CBFs leverage discrete, sequential quadratic programs to achieve successive tasks. However, discrete switching can lead to control input discontinuities which can affect a robot’s performance. Hence, we propose a method which ensures smooth transitions between a sequence of quadratic programs. In particular, a time varying component to the barrier function constraint is introduced which allows for a smooth transition between objectives. Robotic implementation results are provided which illustrate the theoretical framework.

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