Motor Control Apparatus Initial Position Deviation Handling

Solution Overview

Problem

In motor position feedback control systems, especially those with small rotation numbers, initial position deviations lead to oscillations in driving voltage, making it difficult to align the actual rotation position with the target trajectory, resulting in inaccurate stop positions and uneven exposure in applications like focal plane shutter units.

Innovation Solution

A motor control apparatus with a detection unit to monitor actual rotation positions and a processing unit that adjusts initial position deviations within a predetermined range before starting position feedback control, ensuring accurate alignment with target rotation positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If position feedback control is performed on a motor with small number of rotations, then the motor can complete the operation quickly, but oscillation occurs in driving voltage making it difficult to make the actual rotation position coincide with the target trajectory

Engineering Contradiction:

Improveoperation speedVSAvoidposition accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The control unit performs preliminary processing before position feedback control starts to make the initial position deviation fall within a predetermined range. This preliminary action prevents oscillation from occurring in the first place, allowing the motor to operate quickly while maintaining position accuracy throughout the motion.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the initial position deviation is large, then the motor can start from any position, but oscillation occurs in driving voltage causing decrease in accuracy of stop rotation position

Engineering Contradiction:

Improvestarting position flexibilityVSAvoidstop position accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The control unit performs preliminary processing before position feedback control starts to make the initial position deviation fall within a predetermined range. This preliminary action prevents oscillation from occurring in the first place, allowing the motor to operate quickly while maintaining position accuracy throughout the motion.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If position feedback control is performed with small number of rotations, then the shutter operation is fast, but uneven exposure occurs when actual rotation position deviates from target trajectory

Engineering Contradiction:

Improveshutter operation speedVSAvoidexposure uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The control unit performs preliminary processing before position feedback control starts to make the initial position deviation fall within a predetermined range. This preliminary action prevents oscillation from occurring in the first place, allowing the motor to operate quickly while maintaining position accuracy throughout the motion.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11695354B2Motor control apparatus, optical apparatus, and robot manipulator apparatus

Publication Date: 2023.07.04 CANON KK

AI summary

A motor control apparatus includes a detection unit configured to detect an actual rotation position of a motor, a control unit configured to provide position feedback control on the motor so that the detected actual rotation position sequentially approaches a plurality of target rotation positions, and a processing unit configured to perform, before the position feedback control starts, processing to make an initial position deviation fall within a predetermined range, the initial position deviation being a difference between the actual rotation position and a first target rotation position of the plurality of target rotation positions.