Dual Speed Resolver System for Precision Position Feedback
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Solution Overview
Problem
Gimbaled inertial measurement units face challenges in precision and accuracy due to noise and errors from current switching and analog-to-digital conversion, leading to incorrect navigation data, and existing solutions either fail to provide increased precision and bandwidth simultaneously or add complexity, cost, and weight to vehicle designs.
Innovation Solution
A dual speed resolver system that combines coarse and fine resolvers to determine the position of a motor's drive shaft, using a control circuit to generate initial and subsequent position outputs, along with dithered excitation signals and demodulation techniques to enhance precision without increasing speed or bandwidth, and a feedback control system for precise motor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single high-precision resolver is used to determine motor position, then measurement precision is improved, but the system becomes susceptible to noise and errors from current switching and analog-to-digital conversion
Solution Approach 1:
The patent divides the position measurement function into two separate resolvers: a coarse resolver that provides absolute position information and a fine resolver that provides incremental position information. This segmentation allows each resolver to operate in its optimal range, with the coarse resolver being less susceptible to noise and the fine resolver providing high-resolution measurements, thereby resolving the contradiction between precision and noise susceptibility.
Solution Approach 2:
The patent introduces a dual-speed resolver system that acts as an intermediary between the motor and the control system. The coarse resolver outputs at a lower speed provide a noise-resistant reference, while the fine resolver outputs at a higher speed provide precise position data. This intermediary system filters out harmful noise while maintaining measurement precision.
2Measurement precision
If complicated discrete solutions are used to increase precision or bandwidth, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of absolute position sensing and incremental position sensing into a single dual-speed resolver system. By combining the coarse resolver and fine resolver outputs through a unified processing algorithm, the system achieves high precision without requiring separate complex discrete solutions for each function, thereby reducing overall device complexity.
Solution Approach 2:
The dual-speed resolver system serves multiple functions simultaneously: it provides absolute position information, incremental position information, and noise filtering all through a single integrated system. This multi-functionality eliminates the need for multiple separate components and complex discrete solutions, reducing device complexity while maintaining high precision.
3Measurement precision
If additional sensors and processing circuits are added to increase precision and bandwidth, then measurement precision is improved, but weight and volume increase
Solution Approach 1:
The patent changes the operational parameters of the resolver system by using dual speeds: a lower speed for the coarse resolver to reduce noise susceptibility and a higher speed for the fine resolver to increase precision. This parameter change allows the system to achieve high precision feedback without adding heavy hardware, as the precision improvement comes from intelligent signal processing rather than additional physical components.
Data Source
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AI summary
Feedback control circuitry includes rate limiter circuitry configured to generate a rate limited position command based on a position command for a controlled component and based on a speed command for the controlled component. The feedback control circuitry also includes error adjustment circuitry configured to apply a control gain to an error signal to generate an adjusted error signal. The error signal is based on position feedback and the rate limited position command, and the position feedback indicates a position of the controlled component. The feedback control circuitry further includes an output terminal configured to output a current command generated based on the adjusted error signal.