Set-point Control for a Ground-based Reconfigurable Robot

Reconfigurable mobile robots are well suited for inspection tasks in legacy nuclear facilities where access is restricted and the environment is often cluttered. A reconfigurable snake robot, MIRRAX, has previously been developed to investigate such facilities. The joints used for the robot's reconfiguration introduce additional constraints on the robot's control, such as balance, on top of the existing actuator and collision constraints. This paper presents a set-point controller for MIRRAX using vector-field inequalities to enforce hard constraints on the robot's balance, actuator limits, and collision avoidance in a single quadratic programming formulation. The controller has been evaluated in simulation and early experiments in some scenarios. The results show that the controller generates feasible control inputs that enable the robot to retain its balance while moving with less oscillation and operating within the actuation and collision constraints.