Vibration-Type Actuator Backlash Compensation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vibration-type actuators face challenges in achieving high-speed and low-noise driving due to backlash compensation in multi-stage gear systems, leading to increased load and extended compensation periods, which are noticeable to users.
Innovation Solution
The proposed solution involves a vibration-type actuator with a control device that adjusts frequency, pulse width, and phase difference during backlash compensation, transitioning to main driving after compensation, allowing for smoother and faster operation by optimizing acceleration parameters across distinct intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If backlash compensation is performed in multi-stage gear systems, then gear engagement smoothness is improved, but compensation period extends to 0.5-1 second which is noticeable to users
Solution Approach 1:
The patent applies dynamics by making the drive frequency variable during backlash compensation. The control device dynamically adjusts the drive frequency based on the compensation stage: using a first frequency for first-stage gear backlash and a second frequency (higher than the first) for second-stage and subsequent gear backlash. This dynamic frequency adjustment enables the compensation to be completed in 0.2-0.3 seconds, resolving the contradiction between smooth engagement and compensation time.
2Reliability
If multi-stage gear backlash compensation is performed sequentially, then each gear stage is properly engaged, but load increases and compensation speed decreases
Solution Approach 1:
The patent applies parameter changes by modifying the drive frequency parameter according to the backlash compensation stage. When compensating for first-stage gear backlash, a first drive frequency is used. When compensating for second-stage and subsequent gear backlash, a second drive frequency higher than the first is used. This parameter change maintains appropriate compensation speed throughout the process while ensuring reliable gear engagement, resolving the contradiction between reliability and speed.
3Device complexity
If fixed frequency driving is used during backlash compensation, then control is simplified, but compensation period becomes too long for high-speed driving
Solution Approach 1:
The patent implements dynamics by transitioning from fixed frequency control to variable frequency control based on compensation stage. The control device detects which stage of backlash compensation is occurring and adjusts the drive frequency accordingly. This dynamic approach increases productivity by reducing compensation time to 0.2-0.3 seconds while maintaining manageable control complexity through stage-based frequency selection.
Solution Approach 2:
The patent applies parameter changes by modifying the drive frequency parameter according to the compensation stage. Using a higher second frequency for second-stage and subsequent gear backlash compensation accelerates the process compared to using a fixed first frequency throughout. This parameter adjustment significantly improves compensation efficiency while keeping the control logic relatively simple through predefined frequency stages.
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 approach enables low-noise and high-speed driving by reducing the backlash compensation period to about 0.2 to 0.3 seconds, preventing gear collisions and maintaining stable drive speed, thus enhancing the quality of auto focus operations.
Implementation Method 1
a piezoelectric element 202 serving as an electric-mechanical energy conversion element
Implementation Method 2
a moving body 207 configured to contact the first elastic body 201 and frictionally driven
Data Source
AI summary
An actuator includes a vibrating body including an elastic body and a conversion element, a contact body configured to contact the vibrating body, and a device configured to control vibration of the vibrating body. The vibration generated in the vibrating body relatively moves the vibrating body and the contact body. The device performs control for compensation driving of a driving mechanism to be connected to the actuator and control for main driving of the actuator. In the compensation driving, at least one of decreasing a frequency, increasing a pulse width, increasing a phase difference, and decreasing the phase difference of a signal output from the device is performed within a period of the compensation driving, and control to transition to the main driving at end of the period of the compensation driving is performed.