Brake Caliper Interface Sensing for Accurate Braking Torque
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Solution Overview
Problem
Current methods for determining braking torque in brake systems are inaccurate and not independent of axial forces, with existing sensor devices being bulky and limited in their range of measurable forces, making it difficult to integrate them effectively into braking systems.
Innovation Solution
The use of photonic sensors, specifically fiber-optic strain sensors, at the fixing interface between the brake caliper body and support to detect deformation and strain, allowing for precise measurement of braking torque by generating photonic signals that are processed to determine the torque, including temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain sensors are used to detect lateral forces at the brake caliper interface, then the braking torque can be determined indirectly, but the measurement accuracy is poor and the measurable force range is limited
Solution Approach 1:
The patent replaces traditional mechanical strain sensors with fiber optic photonic sensors that use optical interference patterns to detect strain. This substitution enables measurement of much larger force ranges while maintaining high precision, as the optical system is not subject to the same mechanical limitations as conventional strain gauges.
Solution Approach 2:
The patent changes the measurement parameter from electrical resistance change (in strain gauges) to optical wavelength shift (in fiber optic sensors). This parameter change allows for extended measurement ranges and improved accuracy, as optical measurements can detect smaller changes with higher precision and are not limited by the mechanical range of traditional sensors.
2Ease of operation
If compact sensor devices are used to integrate easily into the braking system, then the installation is simplified, but the measurement accuracy and force range are reduced
Solution Approach 1:
The patent nests the fiber optic sensor within the existing brake caliper structure, specifically positioning it to detect strain at the interface between the brake caliper and its mounting bracket. This nesting approach allows the sensor to be integrated into the existing compact space without requiring additional external components, thereby maintaining ease of installation while achieving high measurement accuracy.
3Measurement precision
If measurements are taken at the brake caliper interface, then the braking torque can be determined, but the results are affected by axial forces from tightening torque
Solution Approach 1:
The patent segments the strain measurement into multiple independent fiber optic sensors positioned at different locations and orientations on the brake caliper. By using multiple sensors, the system can differentiate between lateral forces (braking torque) and axial forces (tightening torque) through signal processing, thereby eliminating the interference from axial forces while maintaining accurate braking torque determination.
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 method provides accurate and independent measurement of braking torque, overcoming the limitations of existing technologies by offering compact, robust, and versatile solutions for both fixed and floating caliper disc brakes.
Implementation Method 1
detection performed by photonic sensors (i.e., fiber-optic sensors) at a fixing interface
Implementation Method 2
detecting a deformation and/or strain S locally present at each point of the washer device D
Data Source
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Figure 2A
Figure 2B
AI summary
A method is described for determining a braking torque BT resulting from the actuation of a vehicle braking system, by detection performed at least one fixing interface (i, ii, iii, iv) between a brake caliper body 60 and a respective support 61. The method firstly comprises the step of inserting at least one first washer device D at the aforesaid at least one fixing interface, so that the washer device D is fixed and pressed between the brake caliper body 60 and the brake caliper support 61. The washer device D is susceptible to deformation when subjected to forces, so that the deformation and/or force S locally present at each point of the washer device D is representative of the forces acting at the at least one fixing interface, dependent on the braking torque BT. The washer device D incorporates at least one deformation and/or strain sensor FBG, at a respective detecting position, arranged to detect a deformation and/or strain representative of the three spatial vector components of the force acting on the washer device D at the detecting position. The at least one deformation and/or strain sensor is a fiber-optic strain sensor 2 of the fiber Bragg grating type. The method then comprises the step of detecting, by means of the at least one fiber-optic strain sensor FBG, the local deformation and/or strain S acting in the respective detecting position, and generating a respective at least one photonic signal L representative of the detected deformation and/or strain S; then receiving the at least one first photonic signal L, by an optical reading/interrogation unit 4, optically connected to the at least one fiber-optic strain sensor 2, and generating, at least one electric signal E representative of the detected local deformation and/or strain S, based on the received first photonic signal (L). Finally, the method comprises the step of determining the braking torque BT based on the aforesaid at least one electrical signal E. Furthermore, a corresponding system for determining a braking torque BT, a washer device D adapted to operate in the execution of the aforesaid method, and a sensorized brake caliper, equipped to allow the execution of the aforesaid method, are also described.