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 1i¾źkHz starting from few hundreds of Hz. While the piezoelectric system offers compactness, the 120i¾źW electromagnetic system offers wider bandwidth and is capable of generating suprathreshold stimulus even above 2i¾źkHz. 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 4i¾źkHz, even at high level of excitation, while generating bursts of 100i¾źµm amplitude sine waves. The developed linear charge-drive is suitable for low-current application ~50i¾źmA, maintaining low EMI and small size.