Vibratory Actuator Control for Imaging Apparatus Stability
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Solution Overview
Problem
Existing vibratory actuator control systems for imaging apparatuses face challenges in maintaining consistent control characteristics due to changes in actuator characteristics caused by environmental and external parameters.
Innovation Solution
The proposed vibratory actuator control apparatus includes a vibrating member with an electro-mechanical energy conversion element and a contact member, controlled by a controller that manages their relative movements through specific voltage control stages to maintain consistent driving speed and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frequency control method is used for both acceleration and deceleration, then the control system is simple, but the control characteristics change due to actuator characteristic changes
Solution Approach 1:
The control method is segmented into distinct acceleration and deceleration control sequences. The acceleration sequence uses frequency decrease while the deceleration sequence uses frequency increase, with different control parameters for each phase. This segmentation allows independent optimization of each phase to compensate for actuator characteristic changes, resolving the contradiction between system simplicity and control stability.
Solution Approach 2:
The control system dynamically adjusts the frequency control direction based on the operational phase. During acceleration, the frequency is decreased, while during deceleration, the frequency is increased. This dynamic adaptation to operational conditions allows the system to maintain consistent control characteristics despite actuator characteristic changes, balancing simplicity with reliability.
2Speed
If the driving frequency is changed to control driving speed, then the driving speed can be adjusted, but the control characteristics change due to actuator characteristic variations
Solution Approach 1:
The control sequences incorporate feedback mechanisms where the controller monitors the actual driving speed and adjusts the frequency accordingly. The acceleration and deceleration sequences use frequency changes in opposite directions based on the operational phase, creating a feedback loop that compensates for actuator characteristic changes and maintains consistent control characteristics across different speed levels.
Solution Approach 2:
The system changes the frequency parameter in opposite directions depending on the operational phase: decreasing frequency during acceleration and increasing frequency during deceleration. This parameter change strategy compensates for actuator characteristic variations, allowing speed adjustment while maintaining control characteristic consistency.
3Speed
If pulse width control is used for low-speed region and frequency control for high-speed region, then speed control is effective, but switching between control methods causes control characteristic changes
Solution Approach 1:
The control sequences are designed to transition smoothly between pulse width control and frequency control by preparing the frequency in advance. The acceleration sequence decreases frequency before switching to frequency control, while the deceleration sequence increases frequency, ensuring continuous and consistent control characteristics during the transition between control methods.
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 restricts changes in control characteristics, ensuring stable and consistent performance of the vibratory actuator even with changes in actuator characteristics, thereby improving the reliability of imaging apparatuses.
Implementation Method 1
a vibrating member formed of an electro-mechanical energy conversion element (piezoelectric element) stuck on an elastic member is applied with an alternating voltage (driving voltage) for generating vibrations
Implementation Method 2
The vibratory actuator obtains a driving force by frictionally driving a moving member (contact member) in pressure contact with the vibrating member
Data Source
AI summary
A vibratory actuator control apparatus includes a vibrating member, having an electro-mechanical energy conversion element, and a contact member that contacts the vibrating member. In a second case where the vibrating member and the contact member are brought from a stationary state to a stopped state, an operation sequentially passes through a third stage and a fourth stage. The third stage is for decelerating a relative movement driving speed by applying a driving voltage to the electro-mechanical energy conversion element while maintaining a control parameter of the driving voltage constant and increasing a driving frequency. The fourth stage is for decelerating the driving speed by applying the driving voltage to the electro-mechanical energy conversion element while maintaining the driving frequency constant and decreasing the control parameter of the driving voltage. A start frequency is set based on the driving frequency corresponding to a predetermined driving speed in the third stage.