Resolver Output Demodulation With Phase-Preserving Rectification

Solution Overview

Problem

Gimbaled inertial measurement units face challenges in maintaining precision and accuracy due to noise and errors introduced during the conversion of analog to digital signals and interference from current switching, leading to incorrect navigation data, and existing solutions complicate the system without simultaneously increasing precision and bandwidth.

Innovation Solution

A dual-speed resolver system comprising a coarse resolver for initial position determination and a fine resolver for subsequent position updates, combined with demodulation techniques like dithered excitation signals, recursive median value analysis, and phase-preserving rectification to enhance precision without increasing hardware complexity or bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If discrete solutions are used to increase precision or bandwidth, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveposition measurement precisionVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The resolver system is segmented into two distinct components: a coarse resolver for initial position determination and a fine resolver for subsequent position updates. This segmentation allows each resolver to be optimized for its specific function, with the coarse resolver handling large movements and the fine resolver handling precise adjustments, thereby improving overall measurement precision without requiring a single complex high-precision resolver

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between using coarse resolver data and fine resolver data based on the magnitude of position changes. When large movements occur, the coarse resolver is prioritized; when small adjustments are needed, the fine resolver is used. This dynamic adaptation optimizes measurement precision for different operational conditions while maintaining system simplicity

Inventive Principle:

Principle #15Dynamics

2Productivity

If discrete solutions are used to increase bandwidth, then productivity is improved, but device complexity increases

Engineering Contradiction:

Improveposition update bandwidthVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The resolver system is segmented into two distinct components: a coarse resolver for initial position determination and a fine resolver for subsequent position updates. This segmentation allows each resolver to be optimized for its specific function, with the coarse resolver handling large movements and the fine resolver handling precise adjustments, thereby improving overall measurement precision without requiring a single complex high-precision resolver

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between using coarse resolver data and fine resolver data based on the magnitude of position changes. When large movements occur, the coarse resolver is prioritized; when small adjustments are needed, the fine resolver is used. This dynamic adaptation optimizes measurement precision for different operational conditions while maintaining system simplicity

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If analog to digital conversion is performed, then measurement precision is improved, but object-generated harmful factors increase

Engineering Contradiction:

Improveposition measurement precisionVSAvoidnoise and errors from conversion

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces traditional analog-to-digital conversion processing with a demodulation-based processing approach. Instead of converting resolver outputs to digital signals and then processing them, the system uses demodulation techniques that work directly with the resolver output signals, thereby avoiding the noise and errors introduced by analog-to-digital conversion while maintaining measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the processing parameters and methods for handling resolver outputs. Rather than using standard ADC conversion, the system employs demodulation techniques with dithered excitation signals and recursive median value analysis, changing the fundamental approach to signal processing to eliminate conversion-related errors while preserving precision

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10911061B2System and method for demodulation of resolver outputs

Publication Date: 2021.02.02 THE BOEING CO

AI summary

Demodulation circuitry includes an input terminal configured to be coupled to an analog-to-digital converter (ADC) and configured to receive a plurality of ADC outputs. The plurality of ADC outputs are generated based on resolver outputs. The demodulation circuitry also includes a rectifier configured to rectify the plurality of ADC outputs. Rectifying the plurality of ADC outputs preserves a phase of the plurality of ADC outputs. The demodulation circuitry includes amplitude determination circuitry configured to determine, based on the rectified plurality of ADC outputs, demodulated amplitude values corresponding to the resolver outputs. The demodulation circuitry further includes angle computation circuitry configured to generate position outputs based on the demodulated amplitude values.