Zoom Lens Actuator Control Device Overcoming Stop Friction

Solution Overview

Problem

Existing zoom lens actuator control technologies face issues with response delay and excessive overshoot due to stop frictional forces, and generate vibrations when trying to overcome these forces, particularly in PID control systems.

Innovation Solution

A control device that includes a command sensing unit, a first control unit generating an initial driving force to overcome stop frictional forces, and a second control unit performing PID control, with a control switching mechanism to transition from initial to PID control signals at a predetermined time, minimizing overshoot and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If PID control is used to control the zoom lens actuator, then the lens unit can be moved with sufficient driving force, but response delay occurs due to stop frictional force

Engineering Contradiction:

Improveresponse speedVSAvoidresponse delay

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The control device performs preliminary action by applying a knocking signal before the main driving force is applied. This knocking signal prevents the lens unit from being kept in a stop state by overcoming the stop frictional force in advance, thereby eliminating response delay without causing excessive overshoot.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device uses periodic knocking signals applied at specific intervals before the main driving force. These periodic signals are designed to overcome stop friction without causing continuous vibration, resolving the contradiction between response speed and time loss.

Inventive Principle:

Principle #19Periodic action

2Speed

If excessive driving force is added to overcome stop frictional force, then the lens unit can start moving immediately, but excessive overshoot occurs when stop frictional force converts to motor frictional force

Engineering Contradiction:

Improvestarting speedVSAvoidpositioning precision

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The control device applies partial excessive action by using a knocking signal that is intentionally larger than the normal driving force needed for movement. This knocking signal is applied only briefly to overcome stop friction, then reduced to normal levels, preventing both response delay and excessive overshoot.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control device provides beforehand cushioning by applying a controlled knocking signal that prevents the lens unit from being kept in stop state. This preliminary cushioning force is designed to be sufficient to overcome stop friction but is timed and sized to prevent excessive overshoot when the lens unit starts moving.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Loss of time

If a knocking signal is added to prevent response delay, then the lens unit can start moving immediately, but excessive vibration is generated

Engineering Contradiction:

Improveresponse delayVSAvoidvibration

Core Design Contradiction:

Loss of timeVSObject-generated harmful factors

Solution Approach 1:

The control device uses periodic knocking signals applied at specific intervals before the main driving force. These periodic signals are designed to overcome stop friction without causing continuous vibration, resolving the contradiction between response speed and time loss.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The control device applies partial excessive action by using a knocking signal that is intentionally larger than the normal driving force needed for movement. This knocking signal is applied only briefly to overcome stop friction, then reduced to normal levels, preventing both response delay and excessive overshoot.

Inventive Principle:

Principle #16Partial or excessive action

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 solution enables immediate movement of the zoom lens actuator without delay, reduces overshoot, and minimizes vibration generation by calculating initial driving force based on stop frictional and external forces, simplifying the zoom magnification adjustment system and reducing manufacturing costs.

Implementation Method 1

a first control unit generating an initial control signal which allows the zoom lens actuator to generate predetermined initial driving force required for starting the lens unit

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

the lens unit cannot be immediately moved due to stop frictional force of the lens unit which stops on the guide rail

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS20230333445A1Zoom lens actuator control device and zoom camera using same

Publication Date: 2023.10.19 DONG WOON ANATECH CO LTD

AI summary

A zoom lens actuator control device according to an embodiment of the present invention includes: a command sensing unit sensing a location command for allowing a lens unit which stops at one location on the guide rail to move to a target location on the guide rail; and a control switching unit delivering the initial control signal of the first control unit to the zoom lens actuator before a predetermined control switching time arrives after the location command is sensed by the command sensing unit, and delivering the subsequent control signal of the second control unit to the zoom lens actuator instead of the initial control signal of the first control unit when the control switching time arrives.