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.

A Robot and Control Algorithm That Can Synchronously Assist in Naturalistic Motion During Body-Weight-Supported Gait Training Following Neurologic Injury

“…The advantage of having extra control of individual pressures is that we can prevent undesirable pressure buildup, which causes increased seal friction in the actuator and a reduced passive compliance, leading to a poorer performance while in backdrive mode. We refer the reader to [18], [21], and [22] for more details.…”

“…At a 300 kPa (44 PSI) supply pressure, PAM can generate roughly 600 N (135 lb) of force in the horizontal plane and 300 N (67 lb) vertically. We can achieve sufficiently good force control (approximately 5-10 Hz bandwidth) by applying the nonlinear forcetracking controller we have developed, which controls the gas flow into and out of each chamber of a cylinder [21]. Backdrivability is achieved by setting the desired force to zero.…”

Gait Rehabilitation Device in Central Nervous System Disease: A Review

“…However, the PAM is unable to guide patient pelvic [45], which is capable of guiding pelvic and leg movements. The team also performed pneumatic cylinder modeling and constructed a system that monitors the force generated by the pneumatic cylinders during position control in real time to prevent excessive force from being applied to the patient's body [46]. However, the feed-forward control system that measures and applies the pelvic position of a healthy individual to a patient as reference values sometimes causes considerable force to be applied to the body of the patient, due to differences in individual gait patterns.…”

An Adjustable Single Degree-of-Freedom System to Guide Natural Walking Movement for Rehabilitation

“…More common are such treadmill systems that are designed for use in a dedicated therapy room under the supervision of a physical therapist. For example, the pelvic assist manipulator, PAM, [10], includes a body-weight support and manipulates the hip of the user on the treadmill. The Active Leg Exoskeleton, ALEX, [11][12][13] includes body-weight support and independently actuates the hip and knee joints with the ankle supported by a spring-loaded shoe.…”