Wheel Speed Sensor Error Signal Generation
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Solution Overview
Problem
Current wheel speed sensors in automotive systems face challenges in reliably indicating internal failures or malfunctions to control units, particularly in robustness against electrostatic discharge and electromagnetic compatibility, leading to insufficient error management and feedback.
Innovation Solution
An apparatus comprising an input module to receive periodic sensor signals, a determination module to identify malfunctions, and an output module to provide error signals with a predetermined level of physical quantity differing from the normal signal levels, ensuring reliable error indication to the control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a periodic sensor signal is used for wheel speed measurement, then the sensor can provide continuous rotational speed information, but it becomes difficult to distinguish error states from normal operational states
Solution Approach 1:
The patent applies the principle of using distinct signal levels (analogous to color changes) to indicate different operational states. The sensor unit outputs a periodic signal during normal operation, and when an error is detected, it transitions to outputting a constant signal at a different level, making error states easily distinguishable from normal operational states.
Solution Approach 2:
The patent utilizes periodic action by having the sensor unit output periodic signals during normal operation to indicate healthy state, and switching to constant signal output when errors are detected. This periodic versus constant distinction provides a clear mechanism for error indication while maintaining continuous operational monitoring.
2Reliability
If the sensor unit continuously monitors its own operational state, then internal failures can be detected, but the complexity of the sensor unit increases
Solution Approach 1:
The sensor unit implements self-service by incorporating self-diagnostic capabilities that allow it to monitor its own operational state and automatically indicate errors without requiring external monitoring systems. The determination unit within the sensor unit autonomously detects malfunctions and triggers appropriate error signaling.
Solution Approach 2:
The patent merges the sensing function with the error detection and indication functions into a single integrated sensor unit. By combining these functions, the patent avoids the need for separate monitoring systems, thereby detecting internal failures while minimizing the increase in overall device complexity.
3Device complexity
If the error signal uses the same levels as normal signal (upper and lower levels), then the signaling channel remains simple, but the error signal cannot be distinguished from normal signal levels
Solution Approach 1:
The patent applies distinct signal levels (analogous to color changes) for error indication. The error signal uses a constant level that differs from both the upper and lower levels used during normal periodic signal operation, ensuring that error states are clearly distinguishable while maintaining a relatively simple signaling channel.
Data Source
AI summary
An apparatus for providing an error signal for a control unit, the error signal indicating a malfunction of a sensor unit. The apparatus includes an input module configured to receive a sensor signal from the sensor unit, the sensor signal being a periodic signal between an upper level and a lower level of a physical quantity. Further, the apparatus includes a determination module configured to determine the malfunction of the sensor unit and an output module configured to provide the error signal indicating the malfunction for the control unit. The error signal comprises a predetermined level of the physical quantity which differs from the upper level and from the lower level.