In this article, we address the task and safety performance of data-driven model predictive controllers (DD-MPC) for systems with complex dynamics, i.e., temporally or spatially varying dynamics that may also be discontinuous. The three challenges we focus on are the accuracy of learned models, the receding horizon-induced myopic predictions of DD-MPC, and the active encouragement of safety. To learn accurate models for DD-MPC, we cautiously, yet effectively, explore the dynamical system with rapidly exploring random trees (RRT) to collect a uniform distribution of samples in the state-input space and overcome the common distribution shift in model learning. The learned model is further used to construct an RRT tree that estimates how close the model's predictions are to the desired target. This information is used in the cost function of the DD-MPC to minimize the short-sighted effect of its receding horizon nature. To promote safety, we approximate sets of safe states using demonstrations of exclusively safe trajectories, i.e., without unsafe examples, and encourage the controller to generate trajectories close to the sets. As a running example, we use abrokenversion of an inverted pendulum where the friction abruptly changes in certain regions. Furthermore, we showcase the adaptation of our method to a real-world robotic application with complex dynamics: robotic food-cutting. Our results show that our proposed control framework effectively avoids unsafe states with higher success rates than baseline controllers that employ models from controlled demonstrations and even random actions.

Unknown properties of a robot’s environment are one of the sources of uncertainty in autonomous navigation. This uncertainty has to be accounted for when modelling robot dynamics. For ground vehicles in particular, terrain structure is one of the main environmental factors that can strongly influence the dynamics. Therefore, to ensure the ability of a robot to safely and efficiently navigate new environments, robust motion planning and control systems are needed. This paper investigates a data-driven approach to planning and control based on construction of robust motion primitives (MPs) and corresponding feedback rules that ensure a bounded error along the planned trajectory. The approach is tested in an exploration scenario in which a robot systematically inspects an area consisting of several terrain types with the aim of recognizing changes in dynamical properties, learning new dynamics models when such changes are detected and recording that information for future use. The advantage of incorporating the collected data into motion planning in multi-terrain environments is illustrated via simulation.