Path Planning for Surgery Robot with Bidirectional Continuous Tree Search and Neural Network

Abstract

Solving a thorny issue of real-time path planning for surgery robot in uncertain environments, a novel algorithm named bidirectional continuous tree search (BCTS) is proposed. Most partially observable markov decision process (POMDP) planners address challenges of unknown environments with discrete states, observations and actions, which are fail to automate the operative procedure. However, the BCTS method addresses the issue by handling POMDPs in continuous state, observation and action spaces. The proposed approach has a bidirectional search structure with the intent of greatly improving the calculation efficiency. Meanwhile, Bayesian optimization (BO) algorithm is considered to dynamically sample promising actions while we construct a belief tree. In view of the speed of BO process, the upper and lower bounds of the optimal action values given by fast informed bound (FIB) and point-based value iteration (PBVI) limit the search scope, so we can improve the speed of BO. In addition, we apply an optimal path planning generator, radial basis function neural network (RBFNN), to obtain a smoother trajectory. Finally, simulation of glaucoma surgery has been carried out to explore the best surgical approach. The results show that the introduced structure can effectively guide the surgery robot to perform surgical procedures and receive a real-time as well as smooth path.