Brake Pedal Emulator Sensor Layout for Tolerance-Robust Sensing
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Solution Overview
Problem
Existing brake pedal assemblies often suffer from inaccurate and unreliable sensor measurements due to external factors and mechanical limitations, and lack redundancy in case of sensor failure.
Innovation Solution
A brake pedal assembly with a pair of sensor assemblies mounted on either side of the pedal arm, utilizing inductance and Hall effect sensors with fixed spacing to maintain consistent air gaps and allow for relative axial movement, ensuring accurate and redundant sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor assembly is provided to measure pedal arm movement, then the device complexity is reduced, but the measurement precision and reliability deteriorate due to external factors and mechanical limitations
Solution Approach 1:
The sensing system is divided into multiple sensor assemblies (first and second sensor assemblies) positioned at different locations. Each sensor assembly independently measures pedal arm displacement, and their readings are combined to provide accurate and redundant measurement, resolving the contradiction between simple configuration and precise measurement.
Solution Approach 2:
The system incorporates multiple sensor assemblies that continuously monitor pedal arm displacement and provide feedback signals. This feedback mechanism allows for real-time measurement verification and compensation, improving measurement precision while maintaining manageable system complexity.
2Measurement precision
If multiple sensor assemblies are incorporated to improve measurement accuracy, then the measurement precision improves, but the device complexity increases due to additional mounting requirements and sensor components
Solution Approach 1:
The sensor assemblies are designed with universal mounting capabilities that allow them to be installed at multiple locations on the pedal arm. Each sensor assembly serves multiple functions: measuring displacement, providing redundancy, and enabling cross-validation of measurements, thereby improving precision without proportionally increasing complexity.
Solution Approach 2:
The system utilizes different sensing principles (inductance and Hall effect) in different sensor assemblies, changing the measurement parameters and physical effects employed. This diversity in sensing parameters improves measurement precision across different operating conditions while maintaining a manageable overall system complexity.
3Measurement precision
If sensors are mounted close to the pedal arm to reduce spacing errors, then the measurement precision improves, but the reliability deteriorates due to lateral movement and manufacturing tolerances affecting the air gap
Solution Approach 1:
Instead of relying solely on precise positioning in one dimension (minimizing air gap), the system adds redundancy by placing sensor assemblies at multiple locations and orientations. This multi-dimensional approach compensates for lateral movement and manufacturing tolerances, maintaining measurement reliability even when individual air gaps vary.
Solution Approach 2:
The system incorporates redundant sensor assemblies that are positioned to accommodate expected manufacturing tolerances and lateral movements. By anticipating these variations in advance and designing the system to tolerate them, the measurement reliability is maintained despite variations in air gap spacing.
4Reliability
If redundant sensor assemblies are added to provide fail-safe operation, then the reliability improves, but the device complexity increases due to additional components and mounting requirements
Solution Approach 1:
The system extracts and separates the sensing function into independent, modular sensor assemblies that can be individually mounted and replaced. This modular extraction allows for redundancy without requiring a completely complex integrated system, as each sensor assembly operates independently and can be managed separately.
Solution Approach 2:
The system employs different sensing technologies (inductance sensors and Hall effect sensors) with different operating parameters and physical principles. This parameter diversity provides redundancy through technological variety rather than simply duplicating identical components, improving reliability while managing complexity through functional diversity.
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 sensor system provides accurate and reliable measurements by maintaining consistent spacing and allowing for manufacturing tolerances and lateral movement, enhancing redundancy and accuracy in brake pedal operation.
Implementation Method 1
the first element is an inductance sensor, the second element is an inductance target
Implementation Method 2
the third element is a Hall effect sensor, and the fourth element is a magnet
Data Source
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AI summary
A pedal assembly, a sensing system, and a method for making the same. The sensing system has a first sensor assembly and a second sensor assembly on each side of the assembly. A first element (inductance sensor) and another element (Hall effect sensor) are spaced apart from respective target and magnet to sense displacement of the pedal arm. The target and magnet are connected and pivotally fixed to the pivotal shaft(s) for pivoting in concert therewith and for allowing relative axial movement between. An essentially constant spacing between the first and second elements (inductance and HE sensors) in the axial direction is maintained. Further, the sensing system provides a redundancy for adjustments in build tolerance and pedal lateral movement during operation/loading.