An Interactive Treadmill Under a Novel Control Scheme for Simulating Overground Walking by Reducing Anomalous Force

Since the purpose of treadmill-based locomotor training is to transfer lower extremity coordinative skill to overground walking (OW), it needs to simulate OW as closely as possible for optimal skill transfer. Typical treadmill walking at a preset constant speed is different from realistic overground walking because it is less engaging and more automatic. As a remedy for the limitation, this paper investigates a novel treadmill control scheme that allows users to change walking speed freely. It further simulates natural walking by reducing anomalous force (AF) due to acceleration of the treadmill belt. Adding an attenuator in the scheme effectively diminishes the AF when changing walking speed. The proposed scheme, which requires real-time measurement of pelvic and swing foot motion, was developed for a treadmill with a typical belt length (1.5m). A clinical test was conducted with nine healthy subjects in order to quantitatively evaluate the proposed scheme by comparing it with the two existing control schemes in the literature.