Session: 07-08-01: Multibody Dynamic Systems and Applications
Paper Number: 88828
88828 - Simulating a Piezoelectric-Haptic MEMS Actuator in Low-Frequency Vibration
Haptics are a popular method for providing supplemental feedback. When experiencing ambiguous feedback, users can rely on haptics as another modality to compensate for the presence of noise. Designers frequently rely on haptics for the quick response touch and proprioception can provoke from the user, such as the Tactile Awareness System relied on by combat helicopter pilots. Tactile feedback does not suffer from some of the limitations of other modalities; haptic actuators are being integrated into steering wheels to provide lane departure warnings for distracted drivers. As such, the development and qualification of new haptic feedback methods represents foundational work for future engineers and user experience designers.
The authors explored the idea of a haptic mouse exploiting a documented phenomenon in which tangential loads to a user’s finger are aliased with positional cues. Feedback could not be restricted to a narrow range of vibrations and high-resolution positional control would be critical. Piezoelectric actuators were ideal because they have a broad range of actuation modes; positional actuation is possible, and a continuous range of vibrations is supported into ultrasonic frequencies. The broad vibration range stands in contrast to linear resonance actuators, which have a narrow band of operating frequencies. A flextension-style microelectromechanical system (MEMS) was designed to increase the range of actuation possible with the piezoelectrics preferred by a factor of nearly 10. The flextensional system converted the piezoelectric actuator into a two-degree-of-freedom (DOF) system, with the piezoactuator serving as a cyclic force. The actuator was intended to provide a wide range of feedback, the primary modality being the aliased positional cues with vibration as a secondary feedback mode. For simplicity, a single axis of the complete system was studied and designed.
Simulations of a piezoelectric actuator vibrating with and without a human finger resting on the actuator were studied. The actuator resembles a two DOF system without a finger. With a finger, the actuator becomes a three DOF system. All systems were simulated using MATLAB’s ODE45 solver. Closed-form solutions of single DOF systems are easily calculated; however, the ODE45 solver was used to simulate the single DOF systems for the sake of consistency and to prevent the introduction of confounding variables.
The quality of a single-degree-of-freedom reduction depended on whether the user’s finger was considered. Without a finger, no significant deviations in the system’s behavior were found; the equivalent spring, mass, and damper coefficients match those calculated by standard reduction methods without complication. The addition of a finger complicated the simulation. The frequency behavior of the single-degree-of-freedom system dropped an order of magnitude below the frequencies of the multi-degree-of-freedom system. This drop resulted in discrepancies between the simulated behavior of the multi-degree-of-freedom and its single-degree-of-freedom equivalent.
Presenting Author: Alexander Benson Saint Martin's University
Presenting Author Biography: Alexander Benson is a graduate student in Mechanical Engineering Department of Saint Martin's University.
Authors:
Alexander Benson Saint Martin's UniversitySeth Carl Saint Martin's University
Shawn Duan Saint Martin's University
Simulating a Piezoelectric-Haptic MEMS Actuator in Low-Frequency Vibration
Paper Type
Technical Paper Publication