Lens Drive Control for Smooth Optical Movement
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Solution Overview
Problem
Existing lens-interchangeable camera systems struggle to accurately control optical members with different operation responsiveness and stationary precision, leading to unintended movements when driven by cameras lacking specific functionality, and fail to achieve smooth movement for both slow and fast driving units like DC motors and stepping motors.
Innovation Solution
A drive control apparatus that includes a position acquirer, an instruction inputter, and a controller to determine and output a driving command that adjusts the driving amount based on the position difference between the intended and current positions of the optical member, allowing for smooth movement by optimizing the driving speed of both slow and fast driving units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a stepping motor with high speed driving capability is used, then the driving speed of the optical member is improved, but the optical member moves too quickly near the intended position causing drastic video changes and uncomfortable viewing
Solution Approach 1:
The patent applies dynamics by making the driving amount variable based on the positional relationship between the optical member and its intended position. When the optical member is far from the intended position, a larger driving amount is applied for quick movement. When close to the intended position, the driving amount is reduced to achieve smooth, gradual positioning. This dynamic adjustment of driving parameters resolves the contradiction between high-speed driving and smooth video capture.
2Ease of operation
If proportional control is used to achieve smooth movement near the intended position, then video stability is improved, but the system cannot achieve both fast response for large position differences and smooth control for small position differences with a single motor type
Solution Approach 1:
The patent changes the control parameter from a fixed proportional control ratio to a variable driving amount that depends on the distance between the current and intended positions. This parameter change allows the system to adapt to different motor types (DC motors with slow driving speed and stepping motors with fast driving speed) by adjusting the driving amount dynamically, achieving both fast response when needed and smooth control when near the target position.
3Device complexity
If a camera without specific functionality to acquire lens responsiveness data is used, then device complexity is reduced, but accurate control of optical members with different operation responsiveness cannot be achieved
Solution Approach 1:
The patent applies self-service by enabling the lens apparatus to determine its own driving amount based on its inherent characteristics and the positional relationship with the intended position. The lens apparatus autonomously calculates the appropriate driving amount using its internal controller, eliminating the need for the camera to acquire and process lens responsiveness data. This self-determination mechanism maintains control precision while reducing camera complexity.
Data Source
AI summary
A drive controller for controlling driving of a movable optical member of a lens apparatus, including: a position acquirer acquiring a position of the movable optical member; an instruction inputter receiving a first driving command for driving the movable optical member from an external apparatus; and a controller determining a driving amount so that the movable optical member is driven to a position different from a position corresponding to the first driving command based on the first driving command and the position of the movable optical member every unit time, and outputs a second driving command to the lens apparatus so that the movable optical member is driven by the driving amount within the unit time, wherein the controller sets the driving amount within the unit time larger as a difference between the position corresponding to the first driving command and the position of the movable optical member becomes larger.