Motor Encoder with Dual Detection Units for Failure Monitoring

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Solution Overview

Problem

Conventional motor control systems require additional encoders for reliability monitoring, increasing physical size, weight, and processing costs, and complexity.

Innovation Solution

A motor control system with an encoder that includes a first and second disk on the motor's rotation shaft, each with a detection unit, transmitting safety data for comparison by the motor controller to detect rotation positions, allowing for reliable failure detection without external encoders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an additional encoder is provided separately to monitor encoder reliability, then encoder failure detection capability is improved, but device complexity and physical size increase

Engineering Contradiction:

Improveencoder failure detection capabilityVSAvoidsystem configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the reliability monitoring function into the existing encoder structure by adding a second detection unit that reads a second code pattern on the same encoder disk. This eliminates the need for a separate physical encoder while maintaining dual-encoder functionality for reliability monitoring, thus resolving the contradiction between improved failure detection and reduced system complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The encoder is designed to perform multiple functions: the first detection unit provides primary position feedback while the second detection unit provides redundancy for failure monitoring. Both detection units operate on the same encoder disk, making the encoder universal in providing both operational data and reliability verification without requiring separate dedicated components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If an additional encoder is provided separately to monitor encoder reliability, then encoder failure detection capability is improved, but physical size and weight increase

Engineering Contradiction:

Improveencoder failure detection capabilityVSAvoidencoder assembly weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines multiple detection units into a single encoder assembly that reads from the same encoder disk. The first and second detection units are integrated within the same physical encoder housing, eliminating the need for separate encoder assemblies and thereby reducing the overall weight while maintaining dual-encoder reliability monitoring capabilities

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If an additional encoder is provided separately to monitor encoder reliability, then encoder failure detection capability is improved, but processing cost increases

Engineering Contradiction:

Improveencoder failure detection capabilityVSAvoidprocessing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the reliability monitoring functionality into the existing encoder manufacturing process by integrating a second detection unit that reads a second code pattern on the same disk. This approach leverages the existing encoder infrastructure and eliminates the need for separate encoder assembly, processing, and integration, thereby reducing manufacturing and processing costs while achieving improved reliability monitoring

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If a second detector is provided to detect one rotation of the motor, then rotation count verification is improved, but device complexity increases

Engineering Contradiction:

Improverotation count verificationVSAvoiddetector configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the rotation count verification function with the position detection function by using two detection units on the same encoder disk. The first detection unit reads a first code pattern for position feedback while the second detection unit reads a second code pattern for rotation count verification. Both functions are integrated within the same encoder assembly, eliminating the need for separate detectors and reducing system complexity

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3379205B1Motor control system, control method, encoder, and motor controller

Publication Date: 2019.07.24 YASKAWA DENKI KK

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AI summary

In a motor control system 1 according to the present disclosure, an encoder 40 includes: a first rotation position detection unit 401 configured to detect a rotation position in one rotation of a rotation shaft of a motor 30 from an optical disk 44A; a second rotation position detection unit 402 configured to detect a rotation position in one rotation of the rotation shaft of the motor 30 from a magnetic disk 45A; and a transmission unit 403 configured to transmit first safety data which includes first rotation position data indicating the rotation position detected by the first rotation position detection unit 401 and second rotation position data indicating the rotation position detected by the second rotation position detection unit 402; and a motor controller 10 includes a comparison unit 102 configured to compare the rotation position included in the first rotation position data and the rotation position included in the second rotation position data.