Solenoid Position Sensing via Coil Current Fluctuations
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Solution Overview
Problem
Existing solenoid actuation systems rely on dedicated position sensors, such as hall-effect sensors, which increase complexity, cost, and require additional time and resources for calibration, and represent a potential point of failure.
Innovation Solution
A control system operates a solenoid without a dedicated position sensor by applying a commanded electrical current to the coil, generating current fluctuations to vary the rate of change, and estimating the armature position based on the rate of change of current through the coil, either through inductance calculations or direct correlation with armature positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated position sensor is used to determine armature position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the position sensing function from a dedicated position sensor and relocates it to the control system through electrical measurements. By measuring current fluctuations and calculating inductance changes, the control system directly determines armature position without requiring separate sensing hardware, thereby eliminating the position sensor while maintaining measurement capability.
Solution Approach 2:
The control system is given multiple functions: it not only controls the solenoid actuation but also performs position sensing through electrical measurements. The same control system that manages current to the coil also measures current fluctuations and calculates position, making the system multi-functional and eliminating the need for dedicated position sensing components.
2Measurement precision
If a dedicated position sensor is used to determine armature position, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent removes the dedicated position sensor from the system and extracts its sensing function into the control system's electrical measurements. This elimination of hardware components directly reduces material costs and assembly complexity, making the system more cost-effective while maintaining position measurement precision through electrical parameters.
Solution Approach 2:
The patent replaces expensive dedicated position sensors with inexpensive electrical measurements of current fluctuations. The sensing is achieved through standard electrical parameters already present in the system, using cheap and readily available measurement capabilities rather than specialized sensing hardware.
3Measurement precision
If a dedicated position sensor is used to determine armature position, then measurement precision is improved, but reliability decreases
Solution Approach 1:
By extracting the position sensing function from a dedicated sensor into the control system's electrical measurements, the patent eliminates additional failure points. The same control system that manages actuation also performs sensing, reducing the number of independent components that could fail and improving overall system reliability while maintaining measurement precision.
Solution Approach 2:
The patent merges the position sensing function with the control system, combining two previously separate functions (actuation control and position sensing) into a single integrated system. This consolidation reduces the number of components and potential failure points, thereby improving reliability while maintaining the capability for precise position measurement through electrical parameters.
4Measurement precision
If a dedicated position sensor is used to determine armature position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the position sensing capability from dedicated sensor hardware and relocates it to electrical measurements within the control system. By using current fluctuations and inductance calculations that are already part of the control system's electrical architecture, the patent eliminates the need for additional sensor circuitry while maintaining position measurement precision.
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
Eliminates the need for dedicated position sensors, reducing system complexity and cost while maintaining accurate position estimation, thereby enhancing reliability and efficiency.
Implementation Method 1
initiating, by a control system in electrical communication with the coil, movement of the armature by applying a first commanded electrical current to the coil
Implementation Method 2
estimating, by the control system, a position of the armature based on the rate of change of current through the coil
Data Source
AI summary
In certain embodiments, a method of controlling a solenoid including an armature and a coil includes initiating, by a control system in electrical communication with the coil, movement of the armature by applying a first commanded electrical current to the coil. The method also includes, after the initiating, generating, by the control system, current fluctuations to vary a rate of change of current through the coil. The method also includes estimating, by the control system, a position of the armature based on the rate of change of current through the coil.