Human Step Rehabilitation Using a Robot Attached to the Pelvis

Abstract

This paper describes a new robot capable of manipulating pelvic motion during human step training on a treadmill. The robot, PAM (Pelvic Assist Manipulator), uses two pneumatically actuated subsystems arranged in a tripod configuration to measure and control the pelvis of a person during body weight supported stepping on a treadmill. The device can be used in a back-drivable mode to record pelvic trajectories, either specified manually by a therapist or pre-recorded from unimpaired subjects, then replay these trajectories using a PD position feedback control law in the task space and a non-linear force control algorithm for each piston chamber. The control laws are presented, along with data that demonstrate the ability of the device to record and replay the pelvic motions that occur during normal walking.