Continuous Local Motion Planning & Control for Micro- Air-Vehicles in Complex Environments

This paper considers the guidance and control of unmanned vehicles in complex obstaclerich environments. The need to consider continually the local obstacle space, even when tracking a trajectory that was designed with that s pace in mind, leads to a motion planning architecture with distinct global & local elements. Receding horizon control (RHC) provides a framework to address the continuous local motion planning problem, but typically suffers from the complexity of a control space design, part icularly for a vehicle with fast dynamics. This paper addresses this issue by subdividing the RHC problem into distinct output space (trajectory design) and control space (trajectory t racking) problems. The output space design is implemented as a real-time optimization p roblem, with receding horizon trajectories described by polynomial functions, whi ch can be constrained to vehicle performance limits and sensor confirmed free-space. The control space problem is implemented via multi-loop pure-pursuit style track ing loops with feed-forward demands in each axis. Simulation results based on a nonlinear 6dof model of a quadrotor micro-airvehicle are provided, demonstrating successful handling of the dynamic interaction between the separated output and control space components of the RHC problem.