Dual Inductive PCB Layout for EMI-Resistant Pedal Position Sensing
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Solution Overview
Problem
Existing vehicle pedal position sensing systems using rotary inductive sensors face challenges in accurately determining the position of the pedal due to interference and inefficiencies in signal detection, particularly in environments with complex electromagnetic interference.
Innovation Solution
A dual inductive position sensing arrangement is employed, utilizing a printed circuit board with two transmitters operating at different frequencies and multiple receivers, providing geometric isolation and enhanced signal detection through a star configuration, to accurately determine the position of the pedal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single inductive position sensor is used, then the device complexity is low, but the measurement precision and reliability are insufficient due to interference in signal detection
Solution Approach 1:
The sensing arrangement is segmented into multiple independent transmitter-receiver pairs, with at least two transmitters and two receivers positioned at different locations. Each pair operates independently to provide redundant measurement paths, thereby improving measurement precision while managing complexity through modular architecture
Solution Approach 2:
Multiple transmitter-receiver pairs are merged into a single integrated sensing arrangement that collectively determines pedal position. The combined output from multiple pairs provides enhanced accuracy and reliability compared to a single sensor, while sharing common structural support and signal processing infrastructure
2Reliability
If multiple transmitters and receivers are used, then the signal detection reliability is improved, but the device complexity increases
Solution Approach 1:
The system is divided into multiple transmitter-receiver pairs that can be independently configured and tested. This segmentation allows for modular installation and maintenance, reducing the operational complexity despite having multiple components for improved reliability
Solution Approach 2:
The multiple transmitters and receivers serve dual purposes: they provide redundant measurement paths for improved reliability while also enabling interference cancellation through differential measurement. This multi-functionality justifies the increased component count by extracting additional utility from each element
3Measurement precision
If transmitters and receivers are positioned close together, then the signal strength is high, but the interference between components increases
Solution Approach 1:
Each transmitter-receiver pair is positioned with specific local characteristics optimized for its measurement function. The pairs are distributed at different locations around the pedal rotation axis, with each pair having tailored spacing and orientation to maximize signal strength while minimizing overlap with other pairs, thereby reducing electromagnetic interference
Solution Approach 2:
The structural support members and housing serve as intermediaries that physically separate and electrically isolate the transmitter-receiver pairs. These intermediaries provide mechanical support while maintaining appropriate spacing and shielding to reduce electromagnetic coupling between adjacent components
4Object-generated harmful factors
If geometric isolation is implemented, then the interference is reduced, but the device complexity increases
Solution Approach 1:
The geometric isolation features are merged with the structural support elements of the pedal assembly. The housing and mounting structures simultaneously provide mechanical support and electromagnetic shielding, eliminating the need for separate isolation components and reducing overall complexity while maintaining interference reduction benefits
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
The dual inductive position sensing arrangement enhances accuracy and reliability in detecting pedal position, enabling precise control of vehicle operations such as acceleration and deceleration by minimizing interference and improving signal integrity.
Implementation Method 1
a first transmitter provided on the PCB and having a shape that surrounds a first portion of the PCB; a second transmitter provided on the first portion of the PCB surrounded by the first transmitter
Implementation Method 2
A rotation of the rotary inductive sensor target induces a change in a first electrical voltage of the first receiver and a change in a second electrical voltage of the second receiver
Data Source
AI summary
A pedal assembly for a vehicle that includes a pedal housing; a rotatable pedal; a rotary inductive sensor target rotatable in response to movement of the rotatable pedal; and a rotary inductive position sensing arrangement. The rotary inductive position sensing arrangement includes: a printed circuit board (PCB); a first transmitter provided on the PCB and having a shape that surrounds a first portion of the PCB; a second transmitter provided on the first portion of the PCB surrounded by the first transmitter; and first and second receivers provided on the PCB between the first transmitter and the second transmitter. A rotation of the sensor target induces a change in a first electrical voltage of the first receiver and a change in a second electrical voltage of the second receiver. The rotary inductive position sensing arrangement can be used as a position sensor in traction motors or in other non-pedal applications.