Model-Based Trajectory Planning of a Hybrid Robot for Powerline Inspection

This letter presents the first trajectory planning method for hybrid robot to perform powerline inspection involving obstacle navigation and landing. We develop a geometric model that incorporates constraints for landing the hybrid robot on a powerline, obstacle avoidance, and objectives that maximize the visibility of the powerline during flight. The trajectory generation is achieved via solving a multiple shooting nonlinear programming problem with respect to system dynamics and geometric constraints. The formulation of the problem accommodates both powerline-to-powerline and air-to-powerline trajectory planning scenarios. It runs onboard and is capable of generating trajectories within 50 ms, regardless of whether the hybrid robot's initial state is positioned on the powerline or hovering above it. Through simulation experiments, we illustrate the impact of our proposed geometric model on trajectory planning. Furthermore, real-world experimental results validate the efficacy of the proposed planning method. Compared with the existing feedback-control-based work, the landing and obstacle navigation time are significantly reduced.