Seat Motor Absolute Sensor Diagnostics for Position Accuracy
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Solution Overview
Problem
Existing systems that employ sine/cosine rotational position sensors lack effective methods for diagnosing the health and integrity of these sensors, which is crucial for maintaining accuracy and reliability in actuation systems like active seat suspensions in vehicles.
Innovation Solution
A method and system that utilize a combination of static and dynamic diagnostics, where static diagnostics leverage the geometric relationship between sine and cosine outputs to generate a diagnostic indicator value, and dynamic diagnostics compare high-resolution motor sensor outputs with sine/cosine sensor outputs, using tolerance bands to assess sensor health and detect mechanical failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sine/cosine rotational position sensors are used in actuation systems, then rotational position measurement capability is provided, but there is no effective method for diagnosing sensor health and integrity
Solution Approach 1:
The system performs preliminary diagnostic actions by continuously monitoring the relationship between motor position sensor outputs and sine/cosine sensor outputs. Diagnostic indicator values are calculated in advance to detect potential sensor failures before they affect system operation, enabling proactive maintenance and preventing catastrophic failures.
Solution Approach 2:
The system establishes a feedback mechanism where the controller continuously compares the motor position signal with the sine/cosine output signal, calculates diagnostic indicator values, and uses this feedback to determine sensor health. This closed-loop diagnostic approach enables real-time monitoring and responsive action when sensor degradation is detected.
2Reliability
If sensor diagnostic systems are implemented, then sensor health monitoring capability is improved, but system complexity increases
Solution Approach 1:
The controller serves multiple functions: it controls the actuation system operation and simultaneously performs sensor diagnostic functions. By utilizing existing computational resources and signal processing capabilities already present in the control system, the patent avoids adding separate dedicated diagnostic hardware, thereby minimizing increased system complexity while achieving comprehensive sensor monitoring.
Solution Approach 2:
The diagnostic system is self-sufficient, using its own operational signals (motor position and sine/cosine outputs) to perform self-diagnosis. The system monitors its own health without requiring external diagnostic equipment or additional sensors, reducing overall system complexity while maintaining reliable sensor health monitoring capability.
Data Source
AI summary
A method for sensor diagnostics in a seat suspension system includes: generating, by a first rotational position sensor, a motor position signal representing a rotational position of a motor shaft, the motor shaft being coupled to an output shaft, such that rotation of the motor shaft causes rotation of the output shaft; generating, by a second rotational position sensor, an output signal representing a rotational position of the output shaft coupled to a suspension mechanism to move a vehicle seat relative to a vehicle body; determining a diagnostic indicator value as a function of the motor position signal and the output signal; and determining, based on the diagnostic indicator value, an accuracy of the output signal to represent the rotational position of the output shaft.