Development of Airborne Ultrasonic Haptic Feedback System

Tang, Jun Ren (2019) Development of Airborne Ultrasonic Haptic Feedback System. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

As from the previous haptic feedback method, which is using the device attachment method to detect the tactile sensation on the hand. The tactile sensation only can be felt on hand when the user wears the haptic device, without the haptic device attached on hand, the user cannot feel the haptic feedback in the mid-air. Thus, this project is to develop ultrasound haptic feedback in the mid-air gesture without using an attachment device such as a glove. At the frequency of 40kHz of the ultrasound transducer, the mechanoreceptor of human hand cannot sense the wave from the ultrasound. Therefore, the objective of this project is to design the hardware of transducer array to implement the simulation model to perform volumetric haptic shape rendering. The principle of the acoustic radiation force used to create the tactile sensation from the ultrasound wave. By modulating the phase and amplitude of the ultrasound wave, the acoustic field can be created in a certain area, which called as ‘focal point’. The focal point can be created in form of three dimensions in the mid-air, corresponding each focal point can be creating a certain shape. Thus, by modulating the phase of the ultrasound at 200Hz, we can produce haptic feedback shape in the mid-air which the mechanoreceptor of the human hand can sense the ultrasound wave. The hardware designed requires a driver board to give external power signal to the transducer array which controlled by the Mega Arduino. The simulation will be designed for sending the instruction to the Mega Arduino to give a different signal of phase and amplitude to each transducer. As the experiment set up is placing the transducer array 30 degrees facing the oil surface. Shape rendering in the simulation will be sent to the Arduino then it will produce the focal point on the oil surface for observation and comparing the results between the simulation and actual haptic feedback system. As a result, the driver board able to control the power up to 3Watts to provide a stable transducer signal. The best results for the focal point to be felt on the hand when the period set at 40ms with ON and OFF the transducer array. But for the shape rendering results, in 1 second, the transducer array can create maximum up to 4 points only, which cannot clearly observe the complete shape at a time. This is because of the limitation of the instruction uploading time from the computer to Arduino for controlling the phase and amplitude of each transducer. The application of this project can be improving the realistic of the VR gaming and can be applied to the touchless interface, which can control the system without any control panel that will reduce the space in the control room.