Sensor-Less Driveline Actuator Using Coil Inductance Position Feedback
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Solution Overview
Problem
Existing vehicle driveline components with electromagnetic actuators require expensive sensors to determine the position of axially movable members, which complicates the determination of operational modes and conditions, and may require calibration.
Innovation Solution
A sensor-less system using a coil assembly, oscillator circuit, and controller to generate an oscillating signal based on the inductance of the coil, allowing the determination of the armature's position and system response characteristics, enabling the control of power to maintain desired positions and diagnose potential issues without sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors (such as Hall-effect sensors) are integrated into the electromagnetic actuator system to determine the position of the axially movable member, then the capability to determine position is improved, but the cost and device complexity increase
Solution Approach 1:
The patent extracts the position sensing function from separate physical sensors and integrates it into the existing coil assembly. The coil's inductance naturally varies with armature position, so the position sensing capability is extracted from the actuation function itself, eliminating the need for additional Hall-effect sensors or other position detection devices.
Solution Approach 2:
The coil assembly serves dual functions: it acts as both the electromagnetic actuator (generating magnetic field to move the armature) and the position sensor (detecting armature position through inductance variations). This multi-functionality eliminates the need for separate sensing components, reducing device complexity and cost while maintaining position determination capability.
2Loss of information
If sensors are integrated into the electromagnetic actuator system to determine position, then position information is obtained, but calibration requirements and system complexity increase
Solution Approach 1:
The system uses the coil's own electrical characteristics (inductance) to determine position without requiring external calibration. The inductance varies naturally with armature position, and the controller reads this variation directly to determine position, eliminating the need for manual calibration procedures that would be required with traditional sensor systems.
3Reliability
If traditional sensor systems are used to monitor armature position, then position feedback is obtained, but cost and potential failure points increase
Solution Approach 1:
The patent extracts the position detection function from separate sensing components and embeds it within the coil assembly itself. By using the coil's inherent inductance properties that change with armature position, the system eliminates the need for additional sensors, thereby reducing the quantity of components and potential failure points while maintaining reliable position feedback.
Solution Approach 2:
The coil assembly performs both actuation and sensing functions, reducing the total component count. This multi-functional approach decreases the number of parts that could fail while providing continuous position feedback through the coil's electrical characteristics.
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
Enables accurate determination of the armature's position and state within the driveline component without sensors, reducing costs and complexity, while allowing for efficient power control and diagnostic capabilities.
Implementation Method 1
The coil driver is operable to provide a modulating power signal to the coil to generate an electromagnetic field that causes relative motion between the coil assembly and the armature along the translation axis
Implementation Method 2
The oscillator circuit is configured to generate an oscillating signal having a frequency that varies based on a spacing between the armature and the coil assembly along the translation axis
Data Source
AI summary
A vehicle driveline component includes an armature disposed and moveable along a translation axis, a coil assembly having a coil, a coil driver, an oscillator circuit having a resonant circuit, and a controller. The oscillator circuit is electrically coupled to the coil such that the coil defines a portion of the resonant circuit. The oscillator circuit generates an oscillating signal having a frequency that varies based on a spacing between the armature and the coil assembly along the translation axis. The controller applies a drive signal to the coil driver to have the coil driver provide a modulating power signal to the coil to generate an electromagnetic field that causes relative motion between the coil assembly and the armature along the translation axis. The controller determines a system response characteristic related to the spacing between the armature and the coil assembly based on the oscillating signal.