Compact Resolver Preamp PCB Layout for Low-Noise Joint Sensing
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Solution Overview
Problem
Space-qualified absolute encoders are expensive, large, fragile, and have radiation concerns in the GEO environment, and existing joint position sensing systems fail to meet environmental, performance, and packaging requirements.
Innovation Solution
The Compact Resolver Preamp Assembly (RPA) module, comprising two printed circuit boards, is designed to amplify and condition Inductosyn signals while minimizing noise amplification, supporting high accuracy joint position sensing and radiation tolerance, and is compact enough to be co-located with each joint of a robotic arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If space-qualified absolute encoders are used for joint position sensing, then measurement precision is improved, but device complexity, size, and cost increase while radiation tolerance deteriorates
Solution Approach 1:
The patent replaces expensive, fragile, radiation-sensitive space-qualified absolute encoders with commercial off-the-shelf Inductosyn resolvers that are more robust, smaller, and radiation-tolerant. The resolver technology uses a robust magnetic field-based sensing mechanism that naturally tolerates radiation environments, eliminating the need for expensive space-qualified components while maintaining measurement precision.
Solution Approach 2:
The patent changes the fundamental sensing parameter from optical (in absolute encoders) to magnetic field-based (in Inductosyn resolvers). This parameter change enables radiation tolerance in the GEO environment while maintaining joint position sensing accuracy, as magnetic field sensing is inherently more resistant to radiation effects than optical sensing.
2Measurement precision
If resolver pre-amp electronics are incorporated to reduce noise, then measurement precision is improved, but device size and mass increase
Solution Approach 1:
The patent merges the resolver and pre-amp electronics into a single integrated module, eliminating the need for separate pre-amp components. This integration reduces overall device size and mass while maintaining the noise-reduction benefits of pre-amp electronics, as the pre-amp is optimally positioned immediately at the resolver output.
Solution Approach 2:
The pre-amp electronics are nested within the resolver housing, with the pre-amp circuit board positioned inside the resolver assembly. This nesting arrangement minimizes the overall volume required for the joint position sensing system while ensuring the pre-amp is located in close proximity to the resolver for optimal noise performance.
3Volume of moving object
If resolver pre-amp electronics are not incorporated, then device size is reduced, but measurement precision deteriorates due to noise
Solution Approach 1:
The patent combines the resolver and pre-amp into a single integrated module, achieving both compact size and high measurement precision. The pre-amp is built into the resolver assembly, ensuring low-noise signal conditioning is available in a space-efficient configuration that fits within tight robotic joint packaging constraints.
4Volume of moving object
If compact RPA module design is implemented, then device size is reduced for joint co-location, but device complexity increases
Solution Approach 1:
The patent merges multiple functions (resolver, pre-amp, and signal conditioning) into a single integrated RPA module using two printed circuit boards. This integration achieves compact size for joint co-location while managing complexity through functional consolidation and optimized PCB design.
Solution Approach 2:
The patent segments the RPA module into two separate printed circuit boards: one for the resolver interface and one for the pre-amp and signal conditioning. This segmentation manages complexity by dividing the circuitry into functional modules while maintaining overall compact integration within the resolver housing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The RPA module provides accurate joint position telemetry, reduces noise amplification, and meets the electromagnetic interference and radiation requirements, enabling high-fidelity robotic arm control in geosynchronous orbits.
Implementation Method 1
an N pole Inductosyn stator and an N-1 pole Inductosyn stator defining an Inductosyn secondary
Implementation Method 2
a resolver-to-digital converter (108) for transforming an output signal of the N/N-1 resolver into a digital signal
Data Source
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AI summary
A compact resolver pre-amplification assembly has first and second printed circuit boards. The boards include an interface with an N/N-1 resolver and a resolver-to-digital converter and three signal paths. The first and second circuit boards are contained in a single package configured for mounting on a robotic joint while providing high amplification and noise rejection. Low level sensitive signal are separated from high level excite signals by locating sensitive signals on the first board and excite signals on the second board.