Through the development of a biomechatronic knee prosthesis for transfemoral amputees: Mechanical design and manufacture, human gait characterization, intelligent control strategies and tests

Abstract

This paper presents the development of a biomechatronic knee prosthesis for transfemoral amputees. This kind of prostheses are considered 'intelligent' because they are able to automatically adapt their response at the knee axis, as a natural knee does. This behavior is achieved by characterizing the amputee's gait through the signals captured with instrumentation of a prosthesis, which provides feedback about its current state along the gait cycle and therefore responds with the corresponding control action. In this case, unlike other commercially available intelligent knee prostheses, gait cycle characterization is based on accelerometers signals processed by an events detection algorithm. Two intelligent control strategies are presented: a bio-inspired approach, that consists of using a central pattern generator to generate a knee angle reference to be followed by the prosthesis during walking, and an adaptive scheme, that applies a control action proportional to the knee angle according to an auto-adaptive parameter dependant on gait speed. The mechanical design of the prosthesis is also presented, showing the knee joint mechanism and part of the manufacturing process. Results obtained from walking tests with both able body and amputees are shown, demonstrating the positive performance of the prosthesis in several aspects. Future works aimed at a finished product are also stated.

Bio-Inspired Knee Joint: Trends in the Hardware Systems Development

“…This strategy generates the movement coordinates for lower limb motion during the human gait. These coordinated movements are FIGURE 7 | Mechanical design of prosthetic knee joint with magnetorheological actuator (Torrealba et al, 2010).…”

Conceptual Design of a Fully Passive Transfemoral Prosthesis to Facilitate Energy-Efficient Gait

“…Due to the absence of energy transfer between the knee and ankle joints, even the microprocessor controlled transfemoral prostheses have not shown a large reduction of metabolic energy consumption down to the natural walking. Very well-known example of this type of prostheses, C-Leg, employs a controlled damper, whereas one other example uses a magneto-rheological fluid with varying viscous characteristics as a controllable damper for the automatic adjustment of the prosthesis [8]- [10]. It has been shown that the walking quality improves with this kind of prosthesis [11] and the oxygen consumption decreases during walking at varying speeds compared with the passive transfemoral prostheses [12], [13].…”

A novel prosthetic knee joint with a parallel spring and damping mechanism

“…A biomechatronic knee prosthesis was proposed in. 11 It is an intelligent PKJ based on single-axis mechanism. Although the single-axis joint is simple and small size, the instantaneous center of the single-axis knee joint is the center of the revolving axle, which leads to unnatural gait and inconsistent with the variational instantaneous center in human joint.…”