Gait Simulator Based on the Parallel Stewart-Gough Platform

Abstract

This paper shows a solution used to obtain a normal human gait simulator based on the Stewart-Gough platform parallel mechanism. This simulator, a precise and objective tool, makes it possible to better study the ways humans gait, thus aiding in the diagnosis and rehabilitation treatment of patients with motor injuries, 18 years and over. It is estimated that, in Peru, 37.3% of all handicapped patients who need specialized treatment present motor injuries. The prototype designed in this first stage consists of a fixed base connected to a mobile platform by means of six parallel hydraulic linear actuators (hydraulic cylinders). Additionally, the principal pieces of equipment include position sensors (linear potentiometers) for each actuator, control valves, and a hydraulic unit. Different design programs were used for the analysis and design of the prototype. A preliminary 2D analysis (AutoCAD) of the maximum displacement to be generated made it possible to determine the distances and critical angles of the mechanism. Moreover, Matlab was used to analyze the workspace for normal gait as well as the trajectory of the mobile platform through the application of inverse kinematics. SolidWork was used to model the geometry of the components of the prototype in order to evaluate the shape interference while CosmosWork and Cosmos M, using the finite element method, were used to analyze the forces and critical elements. This simulator will make it possible to research the kinematics and dynamics of a Stewart-Gough platform reproducing repetitions of one movement with a small error margin on position, force, and torque. This will be useful in the design and construction of the simulator