Wearable human–machine interface based on PVDF piezoelectric sensor

Abstract

Flexible and stretchable electronics technologies have been attracting increasing attention owing to their potential applications in personal consumed electronics, wearable human–machine interfaces (HMI) and the Internet of Things (IoTs). This paper proposes an HMI based on a polyvinylidene difluoride (PVDF) sensor and laminated it onto the surface of the skin for signal classification and controlling the motion of a mobile robot. The PVDF sensor with ultra-thin stretchable substrate can make conformal contact with the surface of the skin for more accurate measurement of the electrophysiological signal and to provide more accurate control of the actuators. Microelectro-mechanical system (MEMS) technologies and transfer printing processes are adopted for fabrication of the epidermal PVDF sensor. Sensors placed on two wrists would generate two different signals with the fist clenched and loosened. It can be classified into four signals with a combination of the signals from both wrists, i.e. four control modes. Experiments demonstrated that PVDF sensors may be used as an HMI to control the motion of a mobile robot remotely.

Symbiotic human-robot collaborative assembly

“…Gestures have been an integral part of human communication throughout history. Naturally, the gesture of human hand and its coordination have been at the forefront of research in HRC, resulting in the category of wearable sensors for gesture recognition, serving as an important human-robot interface [10,36,50,79,191,136]. A combination of accelerometer and gyroscope has been described by Asokan et al [10] to sense the orientation of the hand by placing the sensors on the back of the palm, and potentiometer mounted on the acrylic strip attached to the finger to measure the angle as finger moves.…”

“…The sensor material is lightweight and self-powered, enabled by the piezoelectric effect. The PVDF piezoelectric sensors are further investigated for wrist mount, generating robot control signal through the coordination of hand gestures [50]. The PVDF sensor can be easily delaminated from the skin and reused from one wrist to the other.…”

Soft human–machine interfaces: design, sensing and stimulation

“…The commands were remotely delivered by mechanical motions through the six channels. Each signal measured by the pressure sensors or strain gauges would generate different control command for the motion of the robot [123]. It is usually able to become thinner than capacitive sensors.…”

A Chest‐Laminated Ultrathin and Stretchable E‐Tattoo for the Measurement of Electrocardiogram, Seismocardiogram, and Cardiac Time Intervals

“…[13] However, the in-plane elastic stiffness of EMFi is 0.5-1 GPa [14] which is orders of magnitude higher than that of human skin (130 kPa to 20 MPa [15] ). For example, micropatterned PVDF membrane, [19] ribbon-like PVDF embedded in Ecoflex, [20] and PVDF islands interconnected by serpentine metal wires [21] have shown around a 30% stretchability, but their thinness and softness have not been explicitly determined. In contrast, polyvinylidene fluoride (PVDF) is a commercially available piezoelectric polymer that is mechanically robust and biocompatible.…”