Actuating Drive Self-Calibration for Commutation Precision

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Solution Overview

Problem

Existing methods for electrically commutated motors face issues with phase errors due to manufacturing tolerances and backlash in gear, which are exacerbated by temperature changes, leading to unpredictable commutation results and the need for high-precision, expensive position sensors.

Innovation Solution

The method involves recording uncompensated position transmitter values over a full revolution, processing them into sine and cosine signals, calculating correction values, and storing them for error compensation, allowing for self-calibration and compensation of wear and temperature dependencies, enabling phase-accurate commutation with a simple structure using an inexpensive position sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-precision position sensors are used to achieve phase-accurate commutation, then commutation precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecommutation precisionVSAvoidsensor complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms position sensor signals from raw angular position readings into corrected sine and cosine signals through mathematical processing. Correction values for offset and amplitude are calculated and applied to compensate for manufacturing tolerances and operational drift, converting imprecise sensor data into high-precision commutation signals without requiring expensive precision sensors

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces correction values as an intermediary element between the position sensor and the commutation control. These correction values, stored in memory and applied through trigonometric calculations, act as a mediator that compensates for sensor inaccuracies and mechanical imperfections, enabling precise commutation with simple sensors

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If one-off exemplary determination of current supply pattern is used, then manufacturing complexity is reduced, but reliability deteriorates due to temperature changes and wear

Engineering Contradiction:
Improvecalibration simplicityVSAvoidcommutation stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent implements periodic recalculation of correction values during operation, particularly after significant temperature changes or wear events. The system continuously monitors operational conditions and updates correction values as needed, transforming a static one-off calibration into a dynamic periodic adjustment process that maintains reliability throughout the actuator's service life

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The actuator system performs self-calibration by automatically detecting its own operational characteristics and generating correction values without external intervention. The position sensor data is processed through the control unit to automatically calculate and store correction values, enabling the system to self-correct for manufacturing tolerances, wear, and temperature effects

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If simple position sensors are used to reduce cost, then device cost is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvesensor costVSAvoidangular position accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent creates corrected mathematical copies of the raw position sensor signals through sine and cosine transformations. Instead of relying on the physical precision of the sensor, the system generates idealized sinusoidal representations of the position data, corrected for known errors, which are then used for commutation control

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent applies parameter changes to the sensor output signals by calculating offset and amplitude correction values that transform imprecise raw readings into accurate sine and cosine signals. This mathematical transformation compensates for sensor inaccuracies, enabling the use of low-cost sensors without sacrificing commutation precision

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2093877B1Method for operating an actuating drive and actuating drive
Publication Date: 2011.11.23 CONTINENTAL AUTOMOTIVE GMBH
  • EP2093877B1 patent drawingFigure 1

AI summary

The method involves collecting uncompensated measured values from a displacement transducer (6) over a full rotation of a rotor or a rotatably driven element, after initiating the actuating drive. The corresponding correction values are formed in a compensation unit (11) for compensation of angle errors, and the correction values are fed to a storage unit (14) for storage. The position values collected in further operation are error compensated with the correction values and are fed to a commutation unit (12) or a position control unit (13) of a motor control unit (9). An independent claim is included for an actuating drive for executing the actuating drive operating method.