Alessandro Persichetti

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

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.

A Wearable Biomechatronic Interface for Controlling Robots with Voluntary Foot Movements

This paper presents an experimental investigation on a novel interface for high level control of mechatronic systems, by exploiting voluntary users foot movements. Based on a biomechanical analysis of the foot anatomy and joint kinematics, a sensory system is designed for detecting pressure variations on selected areas of the insole, obtained from four different foot movements that can be purposively controlled by the person. A prototype is developed that integrates four sensitive areas, battery, and electronics into a wearable insole; electronics are used for data acquisition and wireless transmission, in order to have a stand-alone device. The prototype foot interface is experimentally tested in the control of a prosthetic hand, as a model of a typical device that can be effectively operated by foot movements. Experimental trials were conducted with ten able-bodied subjects and the results confirmed the usability and effectiveness of the foot interface in terms of correct and prompt transmission of the users intention to the controlled device. Comparative experimental trials were performed with electromyography (EMG)-based control of the same prosthesis, which represents the most advanced interface currently available in clinical implants for amputees. The comparative results showed a significant decrease in required adaptation and learning from the users side

Development of an in-shoe pressure-sensitive device for gait analysis

In this work, we present the development of an in-shoe device to monitor plantar pressure distribution for gait analysis. The device consists in a matrix of 64 sensitive elements, integrated with in-shoe electronics and battery which provide an high-frequency data acquisition, wireless transmission and an average autonomy of 7 hours in continuous working mode. The device is presented along with its experimental characterization and a preliminary validation on a healthy subject.

A novel wearable interface for robotic hand prostheses

This paper presents an experimental investigation on a novel interface for high level control of hand prostheses, based on selected foot movements. A prototype has been developed that integrates four sensitive areas, battery, and electronics for data acquisition and wireless transmission into a wearable insole. The prototype foot interface has been experimentally validated in the control of a robotic hand prosthesis. Comparative experimental trials were conducted with 10 able-bodied subjects, with both the foot interface and an electromyographic (EMG)-based control. The results confirmed the effectiveness of the foot interface in the control of the hand prosthesis and showed a significant decrease in required adaptation and learning from the users side.

Soft artificial tactile sensors for the measurement of human-robot interaction in the rehabilitation of the lower limb

A new and alternative method to measure the interaction force between the user and a lower-limb gait rehabilitation exoskeleton is presented. Instead of using a load cell to measure the resulting interaction force, we propose a distributed measure of the normal interaction pressure over the whole contact area between the user and the machine. To obtain this measurement, a soft silicone tactile sensor is inserted between the limb and commonly used connection cuffs. The advantage of this approach is that it allows for a distributed measure of the interaction pressure, which could be useful for rehabilitation therapy assessment purposes, or for control. Moreover, the proposed solution does not change the comfort of the interaction; can be applied to connection cuffs of different shapes and sizes; and can be manufactured at a low cost. Preliminary results during gait assistance tasks show that this approach can precisely detect changes in the pressure distribution during a gait cycle.

Optoelectronic-Based Flexible Contact Sensor for Prosthetic Hand Application

This paper presents a flexible contact sensor for application on robotic fingers of prosthetic hand. The sensor is intended to provide contact sensing functionality when the finger is interacting with the environment. The sensor is based on optoelectronic infrared components mounted on a flexible substrate and connected by means of elastic electrical wires. The adopted configuration allows high sensitivities and fast responses. An important feature of the sensor is that the activation thresholds for contact sensing can be simply and precisely tuneable.

A novel wearable foot interface for controlling robotic hands

This paper presents an experimental investigation on a novel interface for high level control of robotic hands, based on selected foot movements. A prototype has been developed that integrates 4 sensitive areas, battery, and electronics for data acquisition and wireless transmission into a wearable insole. The prototype foot interface has been experimentally validated in the control of a robotic hand prosthesis. Comparative experimental trials were conducted with 10 able-bodied subjects, with both the foot interface and an EMG-based control, which represents the most advanced interface currently available in clinical implants for amputees. The results confirmed the effectiveness of the foot interface in the control of the hand prosthesis and showed a significant decrease in required adaptation and learning from the users side.