Real-time Control of Whole-body Robot Motion and Trajectory Generation for Physiotherapeutic Juggling in VR

Motor rehabilitation is in increasingly high demand to deal with minor functional motor impairments resulting from stroke, cerebellar ataxia, or Parkinson's disease. Juggling physiotherapy has shown to induce brain plasticity and to improve coordination and balance in this context. The physiotherapy, however, relies on large number of repetitions to be effective which prompts to deploy robots to release the burden on therapists both in terms of time as well as physical strain. This paper provides a framework to enable juggling games for patients in interacting with robots through Virtual Reality (VR). A set of throwing motions is recorded from the therapist and is retargeted to the humanoid robot COMAN's wrist. The respective whole-body motion is then solved in a stack of Quadratic Programs (QP) in a real-time architecture that integrates OROCOS and Gazebo. The resulting motion is finally streamed to VR for animation of the robot and the thrown ball, which the user can catch in VR using a controller device. We regard the VR setting as an essential step towards physiotherapeutic robotic juggling, because it ensures safety of the patients and effective testing of the methods and already has potential for actual therapeutic intervention. The control framework, however, is already validated in this paper for switching to full real-time operation on the physical robot.