Wireless Probe Head Antenna Diversity for Signal Reliability

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Solution Overview

Problem

Existing touch probe systems face challenges in ensuring reliable and secure wireless transmission of probing information, particularly in environments where signal interference and positional changes of the probe relative to the transceiver element can disrupt communication.

Innovation Solution

The system employs two spaced-apart antennas with associated receiver circuits that process radio signals in parallel, allowing for comparison of signal levels and alternating transmission through the antenna with the higher level, ensuring reliable transmission even in unsynchronized conditions, and optionally uses light waves for redundancy to maintain information transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless transmission is used for probe information, then contactless transmission is achieved, but transmission reliability deteriorates due to signal interference and positional changes

Engineering Contradiction:
Improvecontactless transmissionVSAvoidtransmission reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The transmitting end is divided into two independent transmitting units (first transmitting unit with first antenna, second transmitting unit with second antenna). Each unit can independently transmit probe information to the receiving end, providing redundant transmission paths that improve reliability while maintaining contactless operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically changes transmission parameters by selecting different transmitting units based on signal quality. The receiving end determines signal levels from both antennas and selects the antenna with the higher signal level for subsequent transmissions, adapting to positional changes and interference conditions

Inventive Principle:
Principle #35Parameter changes

2Reliability

If signal level comparison and alternating transmission are implemented, then transmission reliability is improved, but device complexity increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of having the transmitting end determine signal quality and switch antennas, the invention inverts the control logic: the receiving end determines signal levels from both antennas and selects which transmitting unit should be used for subsequent transmissions. This approach maintains reliability while distributing the complexity across both ends of the communication system

Inventive Principle:
Principle #13The other way round (Inversion)

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 ensures reliable and secure transmission of probing information, minimizing interference risks and maintaining communication even when radio signals are disrupted, by selecting the best antenna for transmission and adjusting power levels based on signal strength, thereby ensuring consistent data transfer during probe movement.

Implementation Method 1

The rest position of the stylus is understood to mean a position in which the stylus is not in contact with the workpiece to be touched. When the stylus comes into contact with the workpiece, the stylus is deflected from its rest position and an electrical sensor signal is generated by means of a suitable converter if the deflection exceeds a predetermined tactile threshold.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The electrical sensor signal is then often converted into a radio signal, so that in this way a contactless and wireless transmission of the probing information to the transceiver element of the touch probe is achieved.

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 3

the transceiver element or the probe (possibly also the transceiver element and the probe) has two spaced-apart antennas for receiving the radio signal, with the transceiver element or the probe being configured in such a way that the signals transmitted via the radio signal from the information received from both antennas can be processed in parallel

Methodology Applied
Scientific EffectElectromagnetic wave reception: Electromagnetic Induction

Implementation Method 4

a first level of the radio signal, as received by the first antenna, being able to be determined and a second level of the radio signal, as received by the second antenna, being able to be determined and the scanning system having a comparator, by means of which the first level is comparable to the second level

Methodology Applied
Scientific EffectSignal level comparison:

Data Source

PatentEP2682713B1Sensor system and method for operating same
Publication Date: 2020.04.08 DR JOHANNES HEIDENHAIN GMBH
  • EP2682713B1 patent drawingFigure 1~2
  • EP2682713B1 patent drawingFigure 3
  • EP2682713B1 patent drawingFigure 4

AI summary

The system has a probe head (1) comprising a cylindrical stylus (1.2) and a sensor element that generates a sensor signal. The probe head and a transceiver element (2) are configured such that information (BI) e.g. sensing information, is wirelessly transmittable between the probe head and the transceiver element over a radio signal. The transceiver element or the probe head comprises antennas (2.1, 2.2) that are spaced from each other and receive the signal. The transceiver element or the probe head concurrently process the information received by the antennas via the signal. The sensor element is designed as a mechanically operating element e.g. strain gauge and piezo element, or an optically operating element i.e. photoelement, in an optical system. An independent claim is also included for a method for operating a sensor system.