A Review of Current State-of-the-Art Control Methods for Lower-Limb Powered Prostheses.

Lower-limb prostheses aim to restore ambulatory function for individuals with lower-limb amputations. While the design of lower-limb prostheses is important, this paper focuses on the complementary challenge - the control of lower-limb prostheses. Specifically, we focus on powered prostheses, a subset of lower-limb prostheses, which utilize actuators to inject mechanical power into the walking gait of a human user. In this paper, we present a review of existing control strategies for lower-limb powered prostheses, including the control objectives, sensing capabilities, and control methodologies. We separate the various control methods into three main tiers of prosthesis control: high-level control for task and gait phase estimation, mid-level control for desired torque computation (both with and without the use of reference trajectories), and low-level control for enforcing the computed torque commands on the prosthesis. In particular, we focus on the high- and mid-level control approaches in this review. Additionally, we outline existing methods for customizing the prosthetic behavior for individual human users. Finally, we conclude with a discussion on future research directions for powered lower-limb prostheses based on the potential of current control methods and open problems in the field.

Evaluation of safety and performance of the self balancing walking system Atalante in patients with complete motor spinal cord injury.

STUDY DESIGN: Prospective, open label, observational. OBJECTIVES: To present results of the first clinical study on a newly developed robotic exoskeleton (Atalante®, Wandercraft, Paris, France) that enables individuals with spinal cord injury (SCI) to perform ambulatory functions without technical aids. SETTING: Two sites specialized in SCI rehabilitation, France. METHODS: Inclusion criteria were presence of chronic complete SCI (AIS A) ranging from T5 to T12. The study protocol included 12 one-hour training sessions during 3 weeks. Patients walked on floor with robotic assistance and wore a harness connected to a mobile suspension system (without weight-bearing) to prevent from falling. Main outcome was the ability to walk 10 meters unassisted, secondary outcomes were assessment of other ambulatory functions, bladder and bowel functions, pain and spasticity. RESULTS: Twelve patients were enrolled, and 11 completed the protocol, mean age 33,9 years. Six patients had T6 levels of lesion or above. Seven patients passed the 10mWT at the 12th session unassisted (mean walking speed 0.13 m/s) while four required some human help. All patients succeeded at the other ambulatory tests (stand-up, sit-down, balance, turn). There were no significant change for bladder (Qualiveen) or bowel (NBD) functions, neuropathic pain (NPSI, NPRS), yet five patients reported a subjective improvement of their bowel function. Impact on spasticity was variable depending on the muscle examined (Ashworth). Ischial skin erosion was seen in one patient that needed local dressing. CONCLUSION: The Atalante system is safe and enables to perform ambulatory functions in patients with complete SCI.