People fall more often when their gait stability is reduced. Gait stability can be directly manipulated by exerting forces or moments onto a person, ranging from simple walking sticks to complex wearable robotics. A systematic review of the literature was performed to determine: What is the level of evidence for different types of mechanical manipulations on improving gait stability? The study was registered at PROSPERO (CRD42020180631). Databases Embase, Medline All, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, and Google Scholar were searched. The final search was conducted on the 1st of December, 2022. The included studies contained mechanical devices that influence gait stability for both impaired and non-impaired subjects. Studies performed with prosthetic devices, passive orthoses, and analysing post-training effects were excluded. An adapted NIH quality assessment tool was used to assess the study quality and risk of bias. Studies were grouped based on the type of device, point of application, and direction of forces and moments. For each device type, a best-evidence synthesis was performed to quantify the level of evidence based on the type of validity of the reported outcome measures and the study quality assessment score. Impaired and non-impaired study participants were considered separately. From a total of 4701 papers, 53 were included in our analysis. For impaired subjects, indicative evidence was found for medio-lateral pelvis stabilisation for improving gait stability, while limited evidence was found for hip joint assistance and canes. For non-impaired subjects, moderate evidence was found for medio-lateral pelvis stabilisation and limited evidence for body weight support. For all other device types, either indicative or insufficient evidence was found for improving gait stability. Our findings also highlight the lack of consensus on outcome measures amongst studies of devices focused on manipulating gait.

To affect functional relevant task-space gait parameters such as foot placement or progression angle, conventional lower-limb robotic gait rehabilitation devices require active control and synchronization of their actuators. As an alternative, we propose the use of gyroscopic actuators, portable actuators that have the ability to generate torques that are caused by and therefore intrinsically synchronized with the swing motion of the legs. Here we investigate the kinematic and kinetic effects at hip-joint level of self-induced gyroscopic torques of a shank-worn gyroscopic actuator. Preliminary results show the wearer’s swing leg motion can induce gyroscopic effects that significantly alter the kinematics of the hip-joint (p< 0.05 ) for both tested conditions in hip-joint endo/exo rotation and ab/ad-duction.

Weakness of the hip abduction muscles can result in a gait disorder named Trendelenburg gait, which can lead to problems in the hip joint, knees, and ankles. In this paper, the conceptual design of a compliant hip orthosis to prevent Trendelenburg gait is presented. A theoretical analysis and measurements on a technical prototype show a high stiffness ratio between adduction and flexion-extension of the leg, and minimal shear forces from the orthosis on the human body while staying close to the human body.

During gait neurorehabilitation, many factors influence the quality of gait patterns, particularly the chosen body-weight support (BWS) device. Consequently, robotic BWS devices play a key role in gait rehabilitation of people with neurological disorders. The device transparency, support force vector direction, and attachment to the harness vary widely across existing robotic BWS devices, but the influence of these factors on the production of gait remains unknown. Because this information is key to designing an optimal BWS, we systematically studied these determinants in this work. We report that with a highly transparent device and a conventional harness, healthy participants select a small backward force when asked for optimal BWS conditions. This unexpected finding challenges the view that during human-robot interactions, humans predominantly optimize energy efficiency. Instead, they might seek to increase their feeling of stability and safety. We also demonstrate that the location of the attachment points on the harness strongly affects gait patterns, yet harness attachment is hardly reported in literature. Our results establish principles for the design of BWS devices and personalization of BWS settings for gait neurorehabilitation.

One important aspect of gait stability is the control of whole-body centroidal angular momentum H. We recently showed that if sensory-motor impairments affect a person's balance control, control of H can be assisted by control moment gyroscopes (CMGs). However, the effect of CMG technology inherently depends on the size and weight of these actuators, and on the speed of the flywheels they contain. These factors all pose challenges for wearable applications. Here, we show that it is possible to design CMGs light enough for wearable applications, while generating meaningful output torques. Our CMG, weighing 1.187 kg, can exert a peak torque of 15 N m with a torque-tracking bandwidth of 18 Hz. These results are partly due to an integrated model of components and partly to advancements in flywheel velocity control, allowing the speed to safely reach 20 000 rpm. These actuators open up new pathways of building wearable assistive devices for clinical applications.