Linear Actuator Position Estimation Using MR Sensor Signals
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Solution Overview
Problem
Conventional position feedback control systems for linear actuators are hindered by high costs due to the use of expensive mixed-signal interpolation chips and require complex, time-consuming computations, leading to inefficient position estimation and mechanical noise.
Innovation Solution
A method and apparatus that utilize magnetic signals from an MR sensor to generate square and saw-tooth waves, allowing for simple and rapid calculation of the moving part's position without the need for expensive interpolation chips, using a microprocessor for linear approximation and reducing system costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mixed-signal interpolation chip is used for position feedback control, then position estimation accuracy is improved, but system cost increases significantly
Solution Approach 1:
The patent replaces the expensive mixed-signal interpolation chip with a combination of inexpensive components: an ADC for analog-to-digital conversion and a microprocessor for digital signal processing. This substitution uses cheaper, readily available components to achieve the same position estimation function, thereby significantly reducing system cost while maintaining measurement precision.
Solution Approach 2:
The patent substitutes the hardware-based mixed-signal interpolation chip with a software-based algorithm running on a microprocessor. By implementing the interpolation function through digital computation rather than dedicated hardware circuitry, the system achieves the same functionality with lower cost and greater flexibility.
2Device complexity
If conventional algorithms are used for position estimation without interpolation chips, then system cost is reduced, but computation time increases due to complex floating-point operations
Solution Approach 1:
The patent transforms the computational problem from using complex floating-point operations to using simple integer-based arithmetic. By changing the numerical representation and calculation method, the system achieves fast computation suitable for real-time control while maintaining position estimation accuracy, thereby reducing computation time without requiring expensive hardware.
3Device complexity
If stepper motors are used for position control, then system simplicity is maintained, but position speed is too slow and mechanical noise increases
Solution Approach 1:
The patent implements a closed-loop feedback control system using an MR sensor for position detection and a microprocessor for control algorithm execution. This feedback mechanism enables precise position control with faster response speeds and reduced mechanical noise compared to open-loop stepper motor control, while maintaining overall system simplicity through software-based control.
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
This approach simplifies the calculation process, reduces hardware costs, and enhances position resolution, achieving faster and more accurate position estimation while avoiding the limitations of conventional algorithms.
Implementation Method 1
receive magnetic signals from the MR sensor, which include a sine signal and a cosine signal
Data Source
AI summary
A method and an apparatus for estimating the position of a moving part of a linear actuator are provided. The method comprises the following steps. Move the moving part towards a target position. Receive magnetic signals generated by the magneto-resistive sensor of the linear actuator, which include a sine signal and a cosine signal. Then, generate a first square wave, a second square wave, and a regional square wave based on the sine signal and the cosine signal. Generate a saw-tooth wave based on the sine signal, the cosine signal, the second square wave, and the regional square wave. Next, calculate the number of regions which the moving part is across from the origin point based on the first square wave, the second square wave, and the regional square wave. Finally, estimate the current position of the moving part based on the saw-tooth wave and the number of regions.