Ryan Luna, Fast and Optimal Stochastic Motion Planning

Slides

Physical robots suffer from uncertainties. These uncertainties arise from many sources, like when objects move in the environment, sensor data has noise, or when the robot cannot perfectly execute a given command. Motion planning under uncertainty requires more deliberative reasoning about future actions and observations in order to pick the best action at each state in time to achieve a task. This mapping of states to actions is known as a policy. Unfortunately, this kind of deep deliberation and policy construction can require significant computation time and is not suited for online tasks.

To aid in policy computation at runtime, this work proposes a two-phase approach to quickly reconfigure local control policies defined over small, discrete regions of the space in order to find a global control policy that is both robust to uncertainties and allows the stochastic system to achieve its task. Using a Bounded-parameter Markov Decision Process (BMDP), local control policies are computed within discrete regions offline, and one policy from each region is selected by the BMDP to achieve a sequence of tasks specified at runtime. Local policy selection is optimal with respect to a continuously-valued reward function, and experiments show that highly desirable control policies can be computed in seconds.