Angle Detection Apparatus Discontinuity Correction

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Solution Overview

Problem

In multipolar resolvers, the sudden change in electrical angle from 0 degrees to 360 degrees at pole transitions leads to stepwise changes in speed signals, degrading error estimation accuracy when detecting angle information.

Innovation Solution

An angle detection apparatus with a multipolar angle detector, converter, angular velocity signal detector, discontinuity correction unit, and integrator to convert analog angle information into digital, correct discontinuous angular velocities, and integrate corrected signals to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a multipolar resolver is used to detect angle information, then the detection range and resolution are improved, but the sudden change in electrical angle at pole transitions causes discontinuous angular velocity signals that degrade error estimation accuracy

Engineering Contradiction:

Improveangle detection precisionVSAvoiderror estimation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by detecting pole transition events before they cause significant error accumulation. The pole transition detector identifies when the electrical angle wraps around (0° to 360° transition), and the angular velocity corrector proactively adjusts the angular velocity signal at these moments, preventing the discontinuity from degrading subsequent error estimation accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of sudden angle wrapping into a beneficial correction mechanism. By detecting the pole transition event, the system identifies exactly when the angular velocity would become discontinuous and applies a corrective adjustment, transforming the potential error source into an opportunity for signal refinement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Speed

If digital angle signal differentiation is performed to obtain speed signal, then the speed detection capability is improved, but the sudden angle change from 0 to 360 degrees causes stepwise changes in speed signal

Engineering Contradiction:

Improveangular velocity detection capabilityVSAvoidangular velocity signal continuity

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The patent implements feedback by continuously monitoring the electrical angle signal and comparing consecutive values to detect sudden wraps. When a pole transition is detected (angle jumps from near 360° to near 0°), the system provides feedback to the angular velocity corrector, which then adjusts the differentiated velocity signal to maintain continuity, creating a closed-loop correction mechanism.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary component (the angular velocity corrector) between the angle detector and the speed signal output. This intermediary detects pole transitions and mediates the angular velocity signal by applying corrective adjustments, smoothing out the stepwise changes that would otherwise propagate to the final speed output.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If angle signal is detected for every single cycle of electrical angle, then the resolution for each pole is improved, but the temporal discontinuity at pole transitions degrades overall measurement accuracy

Engineering Contradiction:

Improveelectrical angle resolutionVSAvoiderror correction accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the electrical angle measurement into distinct pole cycles and identifying transition points between them. The pole transition detector segments the continuous angle signal into discrete cycles, and the corrector applies targeted adjustments at segment boundaries, preserving high resolution within each cycle while maintaining overall temporal accuracy.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9481394B2Angle detection apparatus, motor having the angle detection apparatus, torque sensor, electric power steering apparatus, and vehicle

Publication Date: 2016.11.01 NSK LTD

AI summary

There are provided an angle detection apparatus configured to correct an error included in angle information output from a multipolar angle detector, a motor having the angle detection apparatus, a torque sensor, an electric power steering apparatus, and a vehicle. A multiplication circuit (12) generates digital electrical angle information (θed) from analog angle information output from a multipolar optical encoder (11), a first differentiator 30 differentiates the electrical angle information (θed) to operate an electrical angular velocity (ωed), a first discontinuity correction circuit (31) carries out processing of correcting a discontinuity of an angular velocity in a temporal change for the electrical angular velocity (ωed), and a digital filter (32) carries out correction processing of reducing a high-frequency noise component for an electrical angular velocity (ωedc) corrected by the first discontinuity correction circuit (31).