A Versatile Emulator for Haptic Communication to Alter Human Gait Parameters

Abstract

Robotic devices that interact with humans at the hands through haptic communication - instead of mechanical power transmission – represent an intuitive way to assist persons with physical disabilities and teach movement skills. Principles of human-human haptic communication during walking could inspire novel robot controllers capable of altering specific spatiotemporal gait parameters, not just walking speed. However, we know little about how hand interactions affect gait parameters, as existing hand-contact robots have several performance limitations that hinder rapid testing of different controllers and parameters. Here we present the design and validation of Slidey, a novel robotic testbed capable of emulating diverse hand interactions to alter human gait parameters. A lightweight, instrumented linear stage translating on a > 5 m long track, Slidey allows overground walking at speeds ≤ 2.4 m/s; high-fidelity current and position control at > 500 Hz and ∼ 6 Hz, respectively; and stable rendering of a range of admittances (mass ≤ 10 kg, damping ≤ 20 N/(m/s)). We show proof-of-concept that Slidey has adequate functionality to target changes in step length or step frequency. Slidey can act as a high-fidelity robotic emulator to rapidly investigate, evaluate, and personalize robot controllers to alter gait through haptic communication at the hand.