Study on Modeling of Surface Acoustic Wave Motor

An equivalent modeling of a surface acoustic wave (SAW) motor is proposed. The equivalent model has an advantage to simulate the motor operating conditions such as speed and output force that is required for design of a servo system. From an investigation for measurements of the motor operation in detail the modeling was carried out. The output force of the motor was measured precisely including a dead zone i.e. no response area at lower driving voltage. The output force and damping coefficient dependences on the driving voltage were introduced into the model with a first lag term due to a slider mass. The motor response at falling down to stop was also introduced. Then the motor model was built fully taking care of the nonlinear characteristics. Simulation results using the motor model concurred well with the measurement results; the model represented the mechanical property of the motor including the nonlinearity.