UC Irvine

In developing wearable controllers, or simply wearables, for gesture based applications, in addition to simply being accurate devices must further be intuitive, body conforming, and unrestricting of motion. The premise behind wearables is that some physical interaction is required to interface with every day electronic devices be it, for example, a keyboard, mouse, remote control, knob, or button. In the sense that humans have a tendency to gesticulate when verbally communicating with other humans, wearables allow humans to communicate with, or rather control, electronic devices through intuitive, programmable, gesticulations. Being presented is the design, development, and quantification of two wearable gesture based controllers.

The first controller, worn on the forearm, uses the thin film piezoelectric polymer Polyvinylidene Fluoride (PVDF) to detect hand motion based muscle contractions. The PVDF was spatially shaded to enhance its sensitivity to the forces being exerted on it. A time delay artificial neural network algorithm was used to process the PVDF signal and identify the hand motion that generated it. Two distinct sets of hand gestures were studied: fist, extension, and flexion and right and left. Using microcontrollers and Bluetooth, applications demonstrating the capabilities of the controller were developed for the right and left gesture set including an Android oscilloscope style application showing PVDF voltage and identified gesture and a Microsoft PowerPoint Add-In that allows for gestures to navigate the presentation.

The second controller uses a bimetallic thin foil strain gauge bonded to the elastomer PDMS mounted on a golf glove above the MPC joint of the right index finger. The dynamic behavior of the sensor was studied and a relation between sensor measurements and MPC joint angle developed. A custom printed circuit board (PCB) featuring a microcontroller and RF communication was developed enabling the device, in response to joint angle, to control the throttle input to a quadcopter.

The fabrication and use of PVDF, in conjunction with its electrostrictive terpolymer P(VDF-TrFE-CTFE), in a self-sensing bimorph beam is also discussed. While bending in the beam is induced by applying voltage across the terpolymer, measured voltage from the PVDF is shown to give real time tip deflection.