Sensing Pressure Distribution on a Lower-Limb Exoskeleton Physical Human-Machine Interface

Abstract

A sensory apparatus to monitor pressure distribution on the physical human-robot interface of lower-limb exoskeletons is presented. We propose a distributed measure of the interaction pressure over the whole contact area between the user and the machine as an alternative measurement method of human-robot interaction. To obtain this measure, an array of newly-developed soft silicone pressure sensors is inserted between the limb and the mechanical interface that connects the robot to the user, in direct contact with the wearer’s skin. Compared to state-of-the-art measures, the advantage of this approach is that it allows for a distributed measure of the interaction pressure, which could be useful for the assessment of safety and comfort of human-robot interaction. This paper presents the new sensor and its characterization, and the development of an interaction measurement apparatus, which is applied to a lower-limb rehabilitation robot. The system is calibrated, and an example its use during a prototypical gait training task is presented.

Oscillator-based assistance of cyclical movements: model-based and model-free approaches

“…More in detail, the human-robot physical interface is intended to provide a safe and comfortable interaction while transferring power between the two agents. Ergonomics studies [41] provide the main design guidelines for these interfaces, which are particularly critical in the case of wearable robots [7], due to the close interaction with the user. The human-robot cognitive interface instead is deputed to the acquisition and transfer of information regarding the cognitive involvement of the patient in the task (e.g., planning, reasoning, execution of a movement).…”

“…This method can be used for both assistive and rehabilitative purposes. Unlike other methods previously used to estimate intended movements, our approach does not rely on inspecting activations by means of direct interfaces at the level of the central or peripheral nervous system or by electromyography (EMG) [7,21,22,36]. EMG-based control has been successfully used to reduce the metabolic cost of walking of a healthy person [38], or to provide full-body daily assistance [20].…”

Rehabilitative Soft Exoskeleton for Rodents

“…Interaction effects between live subjects and robotic devices can be measured indirectly through effort assessment such as Electromyography (EMG) [39], [40] or metabolism monitoring [41] or directly through transducers placed in the interface between the two systems [42], [43]. A preliminary test was performed to compare the force/torque levels of interaction between the exoskeleton and the ankle of the subject to the levels of force applied during manual assistance.…”

Mathematical Modelling of Human Amplifier Robot

“…Some researchers measure this interaction force from the point of connection between the user and the robot, while others calculate the deformation rate of the elastic material placed in the robot link [16], [17]. A new distribute method are used in order to measure the pressure interaction between human and robot [18]. A healthy person worn a lower extremity exoskeleton robot named LOPES and the researchers tested their purposed method.…”