Driving Apparatus Control for Lens Positioning Stability
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Solution Overview
Problem
Existing driving apparatuses for imaging lenses, such as those in cameras, face instability due to variations in load torque during movement, particularly at positions of inversion between positive and negative load, leading to oscillations caused by mismatch between target and control values due to gear backlash.
Innovation Solution
A driving apparatus with a controller that generates driving signals through a weighted sum of open-loop and closed-loop control signals based on the detected position and posture of the lens unit, switching between control methods depending on whether the lens is within a predetermined state range where load torque inversion occurs, to stabilize control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed-loop control is used for the driving device, then positioning accuracy is improved, but control stability deteriorates under load torque inversion conditions due to gear backlash
Solution Approach 1:
The control method dynamically switches between open-loop and closed-loop control based on the lens unit's position. When the lens unit is in a first position range (where load torque inversion occurs), open-loop control is used to maintain stability. When in a second position range, closed-loop control is used to improve positioning accuracy. This dynamic adaptation resolves the contradiction by selecting the appropriate control mode for each operational state.
Solution Approach 2:
The system changes the control parameter (control mode) based on the lens unit's position. By detecting whether the lens unit is in the first or second position range and adjusting the control method accordingly, the system optimizes both stability and accuracy. The controller adjusts the control signal generation method based on position parameters, allowing the system to transition smoothly between control modes.
2Reliability
If open-loop control is used for the driving device, then control stability is improved under load torque inversion conditions, but positioning accuracy deteriorates
Solution Approach 1:
The system dynamically switches between open-loop and closed-loop control based on the lens unit's position. When the lens unit is in a first position range (where load torque inversion occurs), open-loop control is used to maintain stability. When in a second position range, closed-loop control is used to improve positioning accuracy. This dynamic adaptation resolves the contradiction by selecting the appropriate control mode for each operational state.
Solution Approach 2:
The system changes the control parameter (control mode) based on the lens unit's position. By detecting whether the lens unit is in the first or second position range and adjusting the control method accordingly, the system optimizes both stability and accuracy. The controller adjusts the control signal generation method based on position parameters, allowing the system to transition smoothly between control modes.
3Measurement precision
If the driving torque is increased to compensate for load variations, then positioning accuracy is improved, but system complexity increases due to the need for multiple control modes
Solution Approach 1:
The system dynamically switches between open-loop and closed-loop control based on the lens unit's position. When the lens unit is in a first position range (where load torque inversion occurs), open-loop control is used to maintain stability. When in a second position range, closed-loop control is used to improve positioning accuracy. This dynamic adaptation resolves the contradiction by selecting the appropriate control mode for each operational state.
Solution Approach 2:
The system changes the control parameter (control mode) based on the lens unit's position. By detecting whether the lens unit is in the first or second position range and adjusting the control method accordingly, the system optimizes both stability and accuracy. The controller adjusts the control signal generation method based on position parameters, allowing the system to transition smoothly between control modes.
Data Source
AI summary
A driving apparatus performs driving of an object. The apparatus includes a driving device for the driving; a position detector, and a controller. The position detector is configured to detect the position of the object. The controller is configured to generate a first signal for open-loop control of the driving device based on a target velocity of the object, generate a second signal for closed-loop control of the driving device based on the detected position and a target position of the object, and generate a driving signal for the driving device based on at least one of the first signal and the second signal. The controller is further configured to perform weighted summing of the first signal and the second signal to generate the driving signal based on inversion between positive and negative of load for the driving device.