Motion control and coordination in the development of a conceptual gait rehabilitation system

Abstract

A conceptual gait rehabilitation system was developed to generate the coordinated motion of the hip and knee joints according to normal physiological gait pattern with a pair of linkage mechanisms (one for each leg). This article presents the design of a mechanical timing mechanism for the motion control and coordination of the linkage mechanisms in the system. The desired motion of the input crank of the linkage mechanism is first obtained for the control purpose. To facilitate the implementation of different modes of operation of the gait rehabilitation system, a combination of cam and planetary gears is developed to achieve both timing and coordination through mechanical means. Motion simulation of the new timing mechanisms shows that the proper timing of the gait mechanisms, thus the hip and knee joints, is achieved with a constant speed input.

Conceptual design and dimensional synthesis of cam-linkage mechanisms for gait rehabilitation

“…Since the proposed approach is presented to synthesize a mechanism driven at a constant speed, for this consideration the average residual between the generated trajectory and the desired one is 11.5 mm, while the average residuals in X and Y directions are 11.0 mm and 2.7 mm, respectively. It has a similar computational accuracy compared to the results presented in [40], which illustrates the feasibility of the proposed approach. The second case for optimization is to synthesize a cam-linkage mechanism used for vertical-movable mode, where the hip is movable in vertical direction.…”

Conceptual design of a rehabilitation device based on cam-follower and crank-rocker mechanisms hand actioned

“…The greatest challenges in exoskeletons development for paraplegics' locomotion are related to compact, high torque and low-mass actuators and to the development of portable batteries with great autonomy. Furthermore, the robotic devices to lower-limb rehabilitation are very expensive complex systems [1,16] mainly due to the technology of servomotors, drivers and control system, and thus, a simpler device tends to make patients feel more comfortable and safer, which is important to gain their acceptance [17][18][19].…”