Workspace CPG with Body Pose Control for Stable, Directed Vision during Omnidirectional Locomotion

Abstract

In this paper, we focus on the problem of directing the gaze of a vision system mounted to the body of a high-degree-of-freedom (DOF) legged robot for active perception deployments. In particular, we consider the case where the vision system is rigidly attached to the robot's body (i.e., without any additional DOF between the vision system and robot body) and show how the supernumerary DOFs of the robot can be leveraged to allow independent locomotion and gaze control. Specifically, we augment a workspace central pattern generator (CPG) with omnidirectional capabilities by coupling it with a body pose control mechanism. We leverage the smoothing nature of the CPG framework to allow online adaptation of relevant locomotion parameters, and obtain a stable mid-level controller that translates desired gaze orientation and body velocity directly into joint angles. We validate our approach on an 18-DOF hexapod robot, in a series of indoor and outdoor trials, where the robot inspects an environmental feature or follows a pre-planned path relative to a visually-tracked landmark, demonstrating simultaneous locomotion and directed vision.