Multi-turn Absolute Encoder Energy Reduction via Periodic Hall Sensor Sampling
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Solution Overview
Problem
Existing multi-turn absolute encoders require continuous monitoring of the absolute position of a rotatable element, leading to high electric energy consumption, especially when powered by exhaustible sources like batteries.
Innovation Solution
A multi-turn absolute encoder with a magnet and a multi-turn detection group comprising at least three actuatable switches, allowing for the determination of the number of turns and rotation direction without continuous monitoring, using a Hall-effect sensor to detect absolute position only when required, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous monitoring of absolute position is implemented, then reliable turn counting and direction identification are achieved, but electric energy consumption increases
Solution Approach 1:
The patent implements periodic sampling of the absolute position by the Hall sensor instead of continuous monitoring. The sensor takes measurements at specific intervals during rotation, which reduces energy consumption while still providing sufficient data for accurate turn counting and direction identification through the evaluation unit's analysis of position changes between samples.
Solution Approach 2:
The system dynamically adjusts its monitoring approach by using the evaluation unit to analyze position changes between periodic samples. This dynamic evaluation allows the system to reliably determine turn count and direction without requiring constant sensor activation, optimizing the balance between measurement reliability and energy consumption.
2Measurement precision
If Hall sensor continuously detects absolute position, then rotation direction and multi-turn position are accurately determined, but energy consumption increases
Solution Approach 1:
The Hall sensor performs absolute position detection periodically rather than continuously, taking measurements at discrete intervals during the rotation cycle. This periodic sampling maintains measurement precision for determining absolute position, rotation direction, and multi-turn count while significantly reducing the energy consumption associated with continuous sensor operation.
Solution Approach 2:
The system uses partial action by sampling the absolute position at sufficient intervals to maintain detection accuracy without requiring constant monitoring. The evaluation unit processes these partial measurements to derive complete information about turn count and direction, achieving the necessary measurement precision with reduced sensor activity.
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
This approach significantly reduces electric energy consumption by minimizing continuous position monitoring and allows for anomaly detection, providing reliable turn counting and direction identification with potential energy savings.
Implementation Method 1
a Hall sensor and a magnet as a single-turn absolute sensor
Implementation Method 2
a pair of magnetically actuatable switches, typically reed switches, as a turn counter. During the rotation of the magnet, the two switches are alternatively actuated
Data Source
Figure 1a~1c
AI summary
The multi-turn absolute encoder (1) for detecting the absolute position of a rotatable element in plural turns comprises a magnet (2) connected to the element in order to rotate therewith ; an absolute detection device (3) for detecting the absolute position of the element in a single turn; and a multi-turn detection group (4) for determining the number of turns performed by the element, which comprises at least three actuatable switches (4A, 4B, 4C) positioned around the magnet (2) in order to be capable of distinguishing at least three different positions of the element in a single turn.