Ultrasonic Actuator Control System for Slip Reduction
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Solution Overview
Problem
In oscillatory actuators, the direct transmission of vibration from the actuator to the target body leads to friction-induced abrasion when movement is mechanistically limited, causing slips that result in wear and tear on both the actuator and the target body.
Innovation Solution
A control system for oscillatory actuators that includes a base, a movable target body, a piezoelectric actuator generating elliptical motion through combined longitudinal and transverse vibrations, a location detection sensor, and a control section that halts the drive signal when the difference between the target location and the detected location exceeds a threshold, minimizing slip and abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the actuator continues to vibrate when the target body reaches its command location, then the target body can be quickly positioned, but slip and abrasion occur between the actuator and target body
Solution Approach 1:
The control section continuously monitors the position of the target body using a position detection sensor and compares it with the command location. When the position discrepancy falls within a predetermined threshold range, the control section automatically stops the drive signal to the actuator, preventing slip and abrasion. This feedback mechanism enables both rapid positioning and protection against wear.
2Productivity
If the actuator vibrates strongly to move the target body quickly, then positioning efficiency is improved, but mechanical wear increases due to friction at the contact interface
Solution Approach 1:
The control system employs periodic monitoring of the position discrepancy between the target body and command location. When the discrepancy enters the threshold range, the actuator is stopped; when it exits the range, the actuator is restarted. This periodic on-off control achieves efficient positioning while minimizing continuous contact and wear.
3Manufacturing precision
If the threshold for stopping the drive signal is set small, then positioning precision is improved, but the actuator stops frequently causing operational interruptions
Solution Approach 1:
The system uses a predetermined threshold value as a parameter to balance positioning precision and operational continuity. By optimizing this threshold parameter, the system achieves sufficient positioning accuracy while minimizing unnecessary stoppages, thereby maintaining operational efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces slip and abrasion between the actuator and the target body by controlling the drive signal based on location discrepancies, thereby enhancing the mechanical stability and longevity of both components.
Implementation Method 1
an actuator body, including a piezoelectric element and a driver element, for moving the target body with respect to the base by combining longitudinal vibration and transverse vibration of the piezoelectric element to have the driver element make an approximately elliptical motion
Data Source
AI summary
In driving a target body only by one of actuators, the target body is smoothly driven.A drive unit (1) includes a stage (3), a first ultrasonic actuator (4A) for driving the stage (3) in an X direction and a second ultrasonic actuator (4B) for driving the stage (3) in a Y direction. When the stage (3) is driven only in one of the X direction and the Y direction, one of the first and second ultrasonic actuators (4A and 4B) which corresponds to the direction generates composite vibration of longitudinal direction parallel to a contact surface of the stage (3) and bending vibration perpendicular to the contact surface of the stage (3). On the other hand, the other one of the first and second ultrasonic actuators (4A and 4B) generates only longitudinal vibration parallel to the contact surface of the stage (3).