Rotary Encoder Bit Pattern Layout for More Positions in Less Space

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Solution Overview

Problem

Rotary encoders typically require a large diameter to accommodate a finite number of positions, leading to increased size, weight, and cost, as the number of discrete rotational positions increases.

Innovation Solution

A rotary encoder with a non-sequential unique bit pattern is designed, where switches form connections based on a binary string generated by removing circularly-shifted binary values, allowing for a compact form factor while maintaining a high number of discrete rotational positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of discrete rotational positions is increased, then the encoding capability is improved, but the diameter and size of the rotary encoder increase significantly

Engineering Contradiction:
Improveencoding capabilityVSAvoiddiameter
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent transitions from sequential spatial encoding (where position is determined by radial distance from center) to a non-spatial encoding dimension (where position is determined by unique bit patterns regardless of location). This allows multiple positions to be encoded within the same radial distance, enabling high-resolution encoding without increasing encoder diameter.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the encoding parameter from sequential radial positioning to non-sequential unique bit patterns. By using binary strings where each position has a distinctive pattern rather than relying on sequential angular or radial progression, the system achieves higher encoding capacity within the same physical footprint.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the number of discrete rotational positions is increased, then the encoding capability is improved, but the weight of the rotary encoder increases

Engineering Contradiction:
Improveencoding capabilityVSAvoidweight
Core Design Contradiction:
Measurement precisionVSWeight of stationary object

Solution Approach 1:

The patent moves encoding from a spatial dimension (radial distance corresponding to position) to a digital dimension (unique bit patterns). This dimensional shift eliminates the need for additional physical mass to represent higher positions, as encoding is achieved through binary patterns rather than proportional physical expansion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses binary bit patterns to represent positions, where each position is defined by a unique combination of bit states rather than unique physical characteristics. This digital representation allows unlimited positions to be encoded using the same physical components, eliminating weight increases associated with higher position counts.

Inventive Principle:
Principle #26Copying

3Measurement precision

If the number of discrete rotational positions is increased, then the encoding capability is improved, but the cost of the rotary encoder increases

Engineering Contradiction:
Improveencoding capabilityVSAvoidcost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a universal encoding scheme where the same physical encoder structure can represent any number of positions through software-defined bit patterns rather than hardware-specific configurations. This universality allows a single encoder design to serve multiple applications with different position requirements, reducing development and manufacturing costs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the encoding approach from hardware-dependent sequential positioning to software-configurable unique bit patterns. This parameter change allows the encoding capability to be modified through configuration rather than physical redesign, significantly reducing the cost of achieving higher encoding capabilities.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3724607B1Rotary switch or other encoder having non-sequential unique bit pattern and method for design
Publication Date: 2022.08.10 RAYTHEON CANADA LTD
  • EP3724607B1 patent drawingFigure 1A
  • EP3724607B1 patent drawingFigure 1B~1C
  • EP3724607B1 patent drawingFigure 2A~2C

AI summary

An apparatus (100) for rotary encoding includes a knob (102) configured to be rotated. The apparatus also includes multiple switches (304, 402) each configured to selectively form or not form a connection based on a current rotational position of the knob. The apparatus further includes a controller (312) configured to generate or use a digital value associated with the current rotational position of the knob. The digital value is defined by which switches have or have not formed connections. Locations where the switches form the connections are selected such that the digital values uniquely identify different rotational positions of the knob and are non-sequential as the knob is rotated.