Variable Reluctance Transducer Low Speed Detection Circuit
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Solution Overview
Problem
Variable reluctance wheel speed transducers face limitations in detecting low speed rotations due to reduced output as speed decreases, making it challenging to accurately measure wheel speed at low velocities.
Innovation Solution
An electric circuit comprising a transducer, operational amplifier (OP-AMP), and a constant voltage source, where the transducer outputs a variable signal in response to the angular velocity of a wheel assembly, and a sensor monitors the output signal to calculate wheel speed using a pre-determined ratio of the wheel speed and the signal period, ensuring consistent detection across varying speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a variable reluctance transducer is used to detect wheel speed, then the system can operate across a wide speed range, but the output signal amplitude decreases at low speeds, limiting detection accuracy
Solution Approach 1:
The patent changes the parameter being measured from signal amplitude to signal frequency/period. The OP-AMP circuit converts the variable amplitude signal into a square wave where the period corresponds to wheel rotation. This parameter transformation allows accurate measurement at low speeds because frequency detection remains reliable even when amplitude is reduced, directly resolving the contradiction between wide speed range operation and low speed detection accuracy
Solution Approach 2:
The patent replaces the conventional amplitude-based detection method with a frequency-based electronic detection method using an OP-AMP circuit. Instead of measuring signal strength which degrades at low speeds, the system measures the temporal characteristics (period/frequency) of the signal, which remain detectable across the full speed range, thus substituting a flawed measurement approach with a more robust electronic measurement technique
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 system effectively detects wheel speed at low velocities by maintaining consistent output, overcoming the limitations of reduced amplitude signals associated with slow wheel rotations, enabling accurate speed calculation regardless of reduced signal amplitude.
Implementation Method 1
a transducer, the transducer configured to output a variable signal in response to an angular velocity of a rotatable member of a wheel assembly
Data Source
AI summary
Systems and methods for detecting wheel speed are provided. An electric circuit for detecting a speed of a wheel may comprise: a transducer in electronic communication with an operational amplifier (OP-AMP), the transducer configured to output a variable signal in response to an angular velocity of a rotatable member of a wheel assembly; a constant voltage source in electronic communication with the OP-AMP; and a sensor in electronic communication with an output terminal of the OP-AMP configured to monitor an output signal of the OP-AMP, the output signal including a period; and a controller configured to receive the output signal and configured to calculate the speed of the wheel according to a pre-determined ratio of the wheel speed and the period. In various embodiments, the circuit may allow for slow wheel speed detection.