Dahl Friction Model for Driving Characteristics of V-Shape Linear Ultrasonic Motors

Area of Science:

• Mechanical Engineering
• Tribology
• Robotics

Background:

• The Coulomb friction model has limitations in describing the complex contact dynamics between the stator and slider in V-shape linear ultrasonic motors.
• Accurate modeling of friction is crucial for understanding and optimizing the performance of ultrasonic motors.

Purpose of the Study:

• To propose and validate a mechanical model based on Dahl friction theory for the stator-slider contact process in V-shape linear ultrasonic motors.
• To analyze the influence of preload and stator vibration amplitude on friction work and motor performance.
• To address the discontinuity issue in tangential contact force calculation inherent in the Coulomb friction model.

Main Methods:

• Development of a mechanical model incorporating Dahl friction theory and considering the tangential compliance of the stator and slider.
• Staged analysis of dynamic contact and friction processes.
• Simulation of motor performance under varying preload and vibration conditions.
• Experimental validation of the proposed friction-driving model.

Main Results:

• The ratio of friction positive work decreases with increased preload.
• Increased stator vibration amplitude enhances the proportion of positive friction work.
• Improved contact stiffness positively impacts the ultrasonic motor's output performance.
• Asymmetry in the V-shaped vibrator leads to differential left and right running speeds.
• The Dahl-based model overcomes the tangential contact force discontinuity of the Coulomb model.

Conclusions:

• The Dahl friction-driving model provides a reliable and reasonable approach for simulating linear ultrasonic motors, surpassing the limitations of the Coulomb model.
• Optimizing contact stiffness and managing preload are key to enhancing ultrasonic motor performance.
• Understanding vibrator asymmetry is essential for achieving balanced motor operation.