Development of a lower limb rehabilitation exoskeleton based on real-time gait detection and gait tracking

Abstract

Hemiplegia, apoplexia, or traffic accidents often lead to unilateral lower limb movement disorders. Traditional lower limb rehabilitation equipments usually execute walk training based on fixed gait trajectory; however, this type is unsuitable for unilateral lower limb disorders because they still have athletic ability and initiative walking intention on the healthy side. This article describes a wearable lower limb rehabilitation exoskeleton with a walk-assisting platform for safety and antigravity support. The exoskeleton detects and tracks the motion of the healthy leg, which is then used as the control input of the dyskinetic leg with half a gate-cycle delay. The patient can undergo walk training on his own intention, including individual walking habit, stride length, and stride frequency, which likely contribute to the training initiative. The series elastic actuator is chosen for the exoskeleton because the torque output can be accurately detected and used to calculate the assisted torque on the dyskinetic leg. This parameter corresponds to the recovery level of a patient's muscle force. Finally, the walk-assisting experiments reveal that the rehabilitation exoskeleton in this article can provide the necessary assisting torques on the dyskinetic leg, which can be accurately monitored in real time to evaluate a patient's rehabilitation status.

Compliant lower limb exoskeletons: a comprehensive review on mechanical design principles

“…Exoskeleton with series-elastic actuation are heavier than those with pneumatic actuation (see Fig. 4) [25, 26, 40, 64, 65]. It is worth mentioning that the pneumatic actuation usually depends on off-board pressure supplies with a negative impact on portability while favouring lighter structures [42, 59, 66, 67].…”

“…The use of crutches may improve user’s self-confidence, serve as a feedback tool, and reduce the risks of falls [82]. In clinical/research settings, non-ambulatory exoskeleton are usually supported with treadmill-based structures, standing structures or safety harness [26, 36, 38, 42, 59, 60, 65–67, 71, 84, 85]. Apart from the inclusion of these safety devices, balance is a topic that has been largely overlooked in the exoskeleton literature, and should be seriously considered in the future, both from the assessment and control point of view.…”

HYBRID: Ambulatory Robotic Gait Trainer with Movement Induction and Partial Weight Support

“…To address these shortcomings, new ambulatory training systems which allow a higher freedom of movement from the patient have been designed, such as WalkTrainer [27] Nature-gaits [28], SUBAR [29], EXPOS [30], the device presented in [31], MLLRE [32], or MOPASS [33]. However, solutions such as these present several drawbacks, like the inability to easily move the patients from their wheelchairs to standing position.…”

Biomimetic compliant lower limb exoskeleton (BioComEx) and its experimental evaluation

“…MINDWALKER [9] and IHMC [10] employed series elastic actuators as a unit of actuation in the hip and knee joints. Zhang et al [11] also used series elastic actuators to provide torque assistance to the leg with impaired walking function. Beyl et al [12] used pneumatic actuators which drive knee joint of the exoskeleton robot as a torque supply.…”