Compact CMM Touch Probe With Digital Signal Communication

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Solution Overview

Problem

Existing touch probes in coordinate measurement systems face challenges in achieving high accuracy measurements at micron or submicron levels while maintaining a compact configuration, often requiring tradeoffs between size, signal processing, communication complexity, and retrofit ability with existing host machine hardware.

Innovation Solution

A compact touch probe design incorporating internal digital signal processing, a regulated power supply circuit, trigger signal generation, and differential digital communication, all housed within a small footprint and utilizing only two electrical connections, with a specialized supply isolation configuration to isolate power and communication signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If internal digital signal processing and two-way digital communication are added to the touch probe, then probe functionality and communication capability are improved, but probe size and device complexity increase

Engineering Contradiction:
Improveprobe functionalityVSAvoidprobe size
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions (power supply, digital signal processing, two-way communication) into a single integrated circuit board within the probe housing. The electronic circuitry includes a microprocessor, memory, communication interface, and power management all merged into one compact unit that connects to the host machine through a single connector, eliminating the need for separate processing units and multiple connectors.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The touch probe is designed with multi-functional electronic circuitry that can perform both measurement triggering and two-way digital communication using the same physical connections. The system can operate in multiple modes (measurement-only, communication-only, or both simultaneously) through a single integrated interface, making the probe adaptable to various application requirements without adding physical complexity.

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

2Measurement precision

If internal digital signal processing is implemented in the touch probe, then measurement precision and signal processing capability are improved, but the number of wires and electrical connections increase

Engineering Contradiction:
Improvesignal processing capabilityVSAvoidnumber of wires
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines power supply connections and digital communication connections into a single electrical interface. The electronic circuit board processes both power input and digital signals through the same physical connector, eliminating the need for separate wire bundles for power and data transmission.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated electronic circuit board acts as an intermediary that receives both power and digital signals through a single connector interface. The circuit board internally routes and processes these signals separately, providing high-level signal processing capability without requiring multiple external wire connections.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If advanced signal processing and communication features are added to the touch probe, then ease of use and robustness are improved, but retrofit ability with existing host machine hardware deteriorates

Engineering Contradiction:
Improveease of useVSAvoidretrofit ability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The touch probe uses a standard connector interface that can work with both legacy host machines and modern systems. The integrated electronic circuitry automatically adapts its functionality based on the host machine capabilities, providing full digital communication features when available while maintaining backward compatibility with simpler systems.

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

Solution Approach 2:

The system allows dynamic adjustment of communication parameters and processing modes to match the capabilities of the connected host machine. The electronic circuitry can operate in enhanced digital communication mode with modern systems or fall back to basic triggering mode with legacy equipment, maintaining ease of use across different platforms.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3336484B1Touch probe for CMM including digital signal communication
Publication Date: 2019.03.27 MITUTOYO CORP
  • EP3336484B1 patent drawingFigure 1
  • EP3336484B1 patent drawingFigure 2
  • EP3336484B1 patent drawingFigure 3

AI summary

A compact CMM touch probe may include internal digital processing, a regulated power circuit, a trigger signal generating circuit, an interface connector limited to two electrical connections, and a differential signal configuration that inputs and outputs differential digital communication signals (including touch trigger signals) through the two connections, superimposed on a CMM supply voltage connected to them from the CMM. A specialized supply isolation circuit is configured in combination with various probe components and operating parameters, to couple the regulated power supply circuit to the CMM supply voltage at the two connections, while isolating it from loading the differential digital signals, which are AC coupled to the two connections. The differential digital signals may normally comprise touch trigger signals, and intermittent control and data signals, during separate respective time periods. In various embodiments, at least a majority of the differential digital signals are formatted using a DC-balanced encoding scheme.