Affordable Wideband Sensor Coupled Vibrotactile Actuator Systems for Psychophysical Experiments

Generation of high-amplitude high-frequency pure-tone mechanical vibrations over a wide frequency range is required in many applications, such as Vibrotactile (VT) stimulation, material testing and so on. This paper describes development of three different types of actuator systems, pneumatic, electromagnetic and piezoelectric, towards the objective of conducting VT psychophysical experiment above 1 kHz starting from few hundreds of Hz. While the piezoelectric system offers compactness, the 120 W electromagnetic system offers wider bandwidth and is capable of generating suprathreshold stimulus even above 2 kHz. Design and response of the piezoelectric actuator system, including the custom built LVDT coupled with the actuator are detailed in this paper. The frequency response of the tested configuration remains flat over a wide bandwidth till 4 kHz, even at high level of excitation, while generating bursts of 100 µm amplitude sine waves. The developed linear charge-drive is suitable for low-current application ~50 mA, maintaining low EMI and small size.