Wearable human–machine interface based on PVDF piezoelectric sensor

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.