Standing balance is controlled by several inputs, including vision, vestibular sense, and ankle proprioception. Research studies in this field actively engage and manipulate these input mechanisms to examine their effects on the balance output, mainly muscle actuation in the lower limbs. While significant progress has been made, it is often difficult to isolate a single input and test its results on the output. The unique Robot for Interactive Sensor Engagement and Rehabilitation (RISER) has been developed in the UBC CARIS laboratory for controlling each sense independently to further our understanding of human balance control and to present new possibilities for the control of bipedal robots. We intend to use this system and the strategies developed to help safely rehabilitate people who have lost the ability to balance.
Researchers in our lab examine the human balance systems involved in maintaining anterior-posterior standing balance using a unique approach: subjects stand on a six-axis force plate mounted on a six-axis Stewart platform. The subjects are secured to the platform, so they cannot move independently of it. The forces that the subject applies to the forceplate are fed back to the platform controller, creating a simulation of standing balance in which the subject has no risk of falling. Immersive 3D stereo display goggles provide visual balance cues, and galvanic vestibular stimulation (GVS) can be employed to produce vestibular input. Additionally a two axis ‘ankle-tilt’ system has been mounted on top of the platform to control ankle angle in the sagittal plane. This decouples ankle proprioception from vestibular input, as the ankles can be moved independently of the head.
E. R. Pospisil, B. L. Luu, J. Blouin, H. F. M. Van der Loos, and E. A. Croft, “Independent Ankle Motion Control Improves Robotic Balance Simulator,” in IEEE Engineering in Medicine and Biology Conference, 2012, p. 6.