Brake Pedal Sensor Assembly with Hall-Effect and Piezoelectric Redundancy
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Solution Overview
Problem
Brake-by-wire vehicle pedals require accurate position and force sensing for reliable brake application and release, but existing systems lack redundancy and sensitivity in detecting varying pedal positions and forces.
Innovation Solution
A sensor assembly combining a non-contacting Hall-Effect pedal position sensor and a contacting pedal force sensor, with a magnet on the pedal arm and a force application member to exert contact force on the force sensor, providing redundant measurements and improved sensitivity through a sensor housing and pre-load mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sensor is used for pedal position sensing, then the device complexity is reduced, but the reliability decreases due to lack of redundancy
Solution Approach 1:
The patent combines a non-contacting Hall-Effect position sensor and a contacting force sensor into a single integrated sensor assembly. Both sensors are mounted together in one housing with shared mounting structures and pre-load mechanisms, allowing redundant position measurement capabilities while reducing overall system complexity compared to separate sensor systems.
Solution Approach 2:
The patent implements redundant sensing capabilities before failure can occur. By incorporating both a non-contacting Hall-Effect sensor and a contacting force sensor that can independently measure pedal position, the system provides backup measurement capability, ensuring reliable brake operation even if one sensor fails.
2Measurement precision
If a non-contacting Hall-Effect sensor is used for position sensing, then the measurement precision is improved, but the device complexity increases due to additional components
Solution Approach 1:
The patent uses a magnet mounted on the pedal arm as an intermediary element for the Hall-Effect sensor. The magnet creates a magnetic field that the Hall-Effect sensor detects to determine pedal position, enabling non-contacting measurement with high precision while keeping the sensor housing design relatively simple through this magnetic field mediation approach.
3Measurement precision
If a contacting force sensor is used for position sensing, then the sensitivity to force variations is improved, but the reliability decreases due to wear and contact issues
Solution Approach 1:
The patent merges a contacting force sensor (piezoelectric element or strain gauge) with a non-contacting Hall-Effect position sensor in the same assembly. The contacting force sensor provides sensitive force detection capability while the non-contacting Hall-Effect sensor provides reliable wear-free position measurement, allowing the system to use the strengths of both sensor types together.
Solution Approach 2:
The patent replaces the mechanical contact measurement approach with a magnetic field-based Hall-Effect sensor for position detection. This substitution eliminates wear and contact issues associated with purely mechanical sensors while maintaining the ability to detect pedal position, and when combined with the force sensor, provides both sensitivity and durability.
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
Ensures reliable brake operation by accurately determining pedal position and force, allowing for redundant measurements and enhanced detection of pedal positions, even if one sensor fails, and supports varying force applications.
Implementation Method 1
the pedal position sensor being adapted for sensing a change in the magnitude and/or direction of the magnetic field generated by the magnet
Implementation Method 2
the pedal force sensor is a piezoelectric element
Implementation Method 3
the pedal force sensor is a piezoelectric element, a load cell, or a strain gauge
Data Source
AI summary
A vehicle pedal sensor assembly for use in a vehicle brake pedal including a base and a pedal arm pivotally mounted to the pedal base. A sensor housing includes a non-contacting pedal position sensor and a contacting pedal force sensor. The sensor housing is mounted to the base of the vehicle brake pedal. A magnet is mounted to the pedal arm. The pedal position sensor senses a change in the magnitude and/or direction of the magnetic field generated by the magnet in response to a change in the position of the pedal arm for determining the position of the pedal arm. A pedal force application member exerts a force against the pedal force sensor in response to the change in the position of the pedal arm for determining the position of the pedal arm. The force sensor may be a piezoelectric element, a load cell, or a strain gauge.