Active lower limb prosthetics: a systematic review of design issues and solutions

Abstract

This paper presents a review on design issues and solutions found in active lower limb prostheses. This review is based on a systematic literature search with a methodical search strategy. The search was carried out across four major technical databases and the retrieved records were screened for their relevance. A total of 21 different active prostheses, including 8 above-knee, 9 below-knee and 4 combined knee-ankle prostheses were identified. While an active prosthesis may help to restore the functional performance of an amputee, the requirements regarding the actuation unit as well as for the control system are high and the development becomes a challenging task. Regarding mechanical design and the actuation unit high force/torque delivery, high efficiency, low size and low weight are conflicting goals. The actuation principle and variable impedance actuators are discussed. The control system is paramount for a “natural functioning” of the prosthesis. The control system has to enable locomotion and should react to the amputee’s intent. For this, multi-level control approaches are reviewed.

Motorized Biomechatronic Upper and Lower Limb Prostheses—Clinically Relevant Outcomes

“…The question remains if amputees could benefit from positive ankle power in current designs or if the additional weight of an A‐MPA (Empower: approx. 2.2 kg) compared a standard N‐MPA (Vari‐Flex size 26, cat 5: 594 g) eliminates the benefits [95].…”

A Human–Robot Interaction Perspective on Assistive and Rehabilitation Robotics

“…Despite the availability of methods for assessing user improvements during rehabilitation (Gresham et al, 1997), standard protocols that go beyond usability questionnaires are missing for assistive devices: the gold standard for functional assessment would be a quantitative comparison of the gain reached in certain activities with and without the device. Such an assessment is, however, a complex task due to the sheer variety of assistive devices, as reviewed in the studies by Dollar and Herr (2008), Yan et al (2015), and Windrich et al (2016). …”

“…This stems from societal needs such as applications in healthcare, for example, mobility aids for people who are aging or with motor impairments (Dollar and Herr, 2008; Windrich et al, 2016), or in industry, such as the augmentation of workers carrying heavy loads (Dollar and Herr, 2008; Yan et al, 2015). Even though device designs have the functionality to perform desired tasks, many robotic devices demonstrate limited effectiveness not only due to technical limitations (Dollar and Herr, 2008; Yan et al, 2015; Windrich et al, 2016) but also due to insufficient knowledge about the human (Yan et al, 2015). Thus, assistive and rehabilitation robotics research and applications appear to require human-oriented approaches, since critically the devices interface with humans (Yan et al, 2015; Christ and Beckerle, 2016).…”

Stiffness Control of Variable Serial Elastic Actuators: Energy Efficiency through Exploitation of Natural Dynamics

“…Potential applications reach from robotic support for industry workers to assistive and rehabilitation robotics. In both, elastic properties foster human safety [3,4] and can provide motion assistance to their users [5,6]. Regarding the latter, elastic actuators have the potential to distinctly improve energy efficiency.…”