Capacitive Obstacle Detection with PLL Frequency Stabilization

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Solution Overview

Problem

Existing obstacle detection systems using static capacitance face challenges in manufacturing complexity, reliability degradation, and sensitivity issues due to frequency tuning dependencies and dead points, leading to productivity and detection accuracy problems.

Innovation Solution

The integration of a phase lock loop system with RF oscillators allows for easy adjustment and maintenance of oscillation frequencies, eliminating the need for complex frequency tuning and reducing dead points by using multiple oscillators that oscillate at different frequencies, thereby enhancing manufacturing productivity and detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If frequency tuning is performed manually during manufacturing, then oscillation frequency accuracy is improved, but manufacturing complexity and time increase

Engineering Contradiction:

Improveoscillation frequency accuracyVSAvoidmanufacturing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The system performs frequency tuning automatically using a microcontroller to control the tuning capacitor, eliminating the need for manual intervention. The microcontroller adjusts the capacitor based on feedback from frequency detection circuits, enabling the system to self-tune during manufacturing without requiring skilled operators or extensive manual adjustment time.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system incorporates feedback mechanisms where frequency detection circuits monitor the actual oscillation frequency and provide this information to the microcontroller. The microcontroller then adjusts the tuning capacitor accordingly to maintain the desired frequency, creating a closed-loop control system that ensures frequency accuracy while automating the tuning process.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If frequency tuning is performed manually during manufacturing, then oscillation frequency accuracy is improved, but manufacturing cost and complexity increase

Engineering Contradiction:

Improveoscillation frequency accuracyVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

3Device complexity

If a single RF oscillator is used, then device simplicity is maintained, but dead points appear causing detection accuracy degradation

Engineering Contradiction:

Improveoscillator configuration simplicityVSAvoidobstacle detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system divides the oscillation function into multiple RF oscillators operating at different frequencies. Each oscillator covers specific frequency ranges, and by segmenting the detection task across multiple frequency bands, the system eliminates dead points where a single oscillator would fail to detect obstacles. The microcontroller coordinates the multiple oscillators to provide continuous coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses multiple RF oscillators that operate periodically at different frequencies to scan through the detection range. By switching between different frequency oscillators in a periodic manner, the system ensures that dead points at any given frequency are compensated by other oscillators operating at different frequencies, maintaining continuous detection capability.

Inventive Principle:

Principle #19Periodic action

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 simplifies the manufacturing process, improves reliability by maintaining consistent oscillation frequencies, and enhances detection accuracy by minimizing dead points and improving sensitivity in obstacle detection systems.

Implementation Method 1

a phase lock loop section for maintaining the oscillation frequency of the RF oscillator to a selected value

Methodology Applied

Scientific EffectPhase lock loop:

Implementation Method 2

detecting a change in the static capacitance... The static capacitance of the sensor strip 14 varies depending on if there is an obstacle in the vicinity thereof or not

Methodology Applied

Scientific EffectStatic capacitance detection: Capacitance

Implementation Method 3

an RF oscillator 42 for generating a high frequency signal of a variable RF oscillation frequency fRF

Methodology Applied

Scientific EffectRF oscillation:

Data Source

PatentUS7876107B2Obstacle detection system and obstacle detection method thereof

Publication Date: 2011.01.25 AUTO TECH CO LTD

AI summary

An obstacle detection system includes a static capacitance detection module including a sensor strip for detecting a static capacitance, an RF oscillator connected to the sensor strip, a phase lock loop section for maintaining the oscillation frequency of the RF oscillator to a selected value and a first MCU for controlling the operation of the phase lock loop section, a control module including a second MCU for remotely controlling the first MCU of the static capacitance detection module and a transmission line for connecting the static capacitance detection module and the control module and transmitting the information acquired by the first MCU so as to be transmitted to the control module, a control signal to be transmitted from the second MCU to the first MCU and drive power of the static capacitance detection module.