Vibration-Type Actuator Control for Acceleration Slip
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Solution Overview
Problem
Existing vibration-type actuators face challenges in achieving desired acceleration and deceleration performance due to slip occurring on the frictional sliding surface between the vibrating body and the driven body, leading to inefficient power consumption and reduced efficiency.
Innovation Solution
A control apparatus that includes a vibration detecting unit, a relative speed detecting unit, and a vibration control unit to monitor and control the vibration state and relative speed, adjusting frequency, voltage, and phase difference of the AC signals supplied to the piezoelectric element to minimize slip and enhance acceleration and deceleration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-frequency vibrations are generated in the vibrating body to move the driven body, then the actuator can perform basic driving function, but slip occurs on the frictional sliding surface leading to poor acceleration and deceleration performance
Solution Approach 1:
The patent applies dynamics by making the vibration frequency variable rather than fixed. The control unit dynamically adjusts the vibration frequency based on the operational state (acceleration, constant speed, deceleration) to optimize performance. During acceleration and deceleration phases, the frequency is adjusted to prevent slip, while during constant speed operation, the frequency is optimized for efficiency.
Solution Approach 2:
The patent changes the vibration frequency parameter according to different operational conditions. By varying the frequency parameter in response to acceleration and deceleration demands, the system prevents slip occurrence while maintaining efficient driving. The frequency is increased during acceleration/deceleration to improve traction and reduced during constant speed to save energy.
2Speed
If the vibration frequency is increased to improve acceleration performance, then acceleration performance improves, but power consumption increases
Solution Approach 1:
The system dynamically adjusts vibration frequency based on real-time operational needs. During acceleration phases, frequency is increased to improve performance, but during constant speed operation, frequency is reduced to minimize power consumption. This dynamic adaptation resolves the contradiction between acceleration performance and energy efficiency.
Solution Approach 2:
The patent employs periodic modulation of vibration frequency that aligns with the operational cycle (acceleration-constant speed-deceleration). The frequency is periodically adjusted to match the demand, ensuring high performance during transient phases while maintaining low energy consumption during steady-state operation.
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
The control apparatus effectively reduces slip rates, improves driving efficiency, and decreases power consumption, while allowing for rapid acceleration and deceleration, thereby balancing performance and power usage in vibration-type actuators.
Implementation Method 1
The vibrating body is constructed by, for example, joining an electro-mechanical energy conversion element such as a piezoelectric element to an elastic body. In the vibration-type actuator, alternating-current (AC) driving voltage is applied to the electro-mechanical energy conversion element to generate high-frequency vibrations in the vibrating body
Implementation Method 2
a vibration-type actuator which brings a vibrating body and a driven body into pressure contact with each other and excite vibrations in the vibrating body to move the vibrating body and the driven body relatively to each other
Data Source
AI summary
A control apparatus for a vibration-type actuator which improves acceleration performance and deceleration performance in driving the vibration-type actuator. The vibration-type actuator moves a vibrating body and a driven body relatively to each other. A vibration state of the vibrating body is detected based on a vibrating voltage or driving current generated in response to vibrations of the vibrating body. A relative speed of the vibrating body and the driven body is detected, and based on the detected vibration state and the detected relative speed, the vibration state of the vibrating body is controlled.