Angle Detection Device Amplitude Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional angle detection systems using magnetic sensors suffer from reduced accuracy due to the need for precise sensor selection, magnetization, and the addition of offset errors when amplifying sinusoidal signals, leading to increased costs with the use of operational amplifiers and additional circuits.
Innovation Solution
An angle detection device employing multiple Hall sensors with different phases to output sinusoidal signals, a rotation calculation unit to detect the angle, and an amplitude comparison unit to correct the amplitude errors by adjusting the drive input voltage, eliminating the need for additional circuits to cancel offset errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a variable amplifier using an operational amplifier is used to amplify the magnetic sensor output signal, then the amplitude of the output signal can be controlled, but offset errors are added to the sinusoidal signal which degrades angle detection precision
Solution Approach 1:
The patent extracts and removes the harmful offset component from the amplified signal by comparing the amplified signal with an ideal sinusoidal reference signal and taking only the difference (error signal). This separates the useful sinusoidal component from the harmful offset component, eliminating the precision degradation caused by operational amplifier offset.
Solution Approach 2:
The patent implements a feedback mechanism where the amplified signal is continuously compared with the reference signal, and the error signal is fed back to correct the amplification process. This feedback loop dynamically compensates for offset errors and maintains high angle detection precision while allowing amplitude control.
2Measurement precision
If a chopper switch and chopper demodulator are added to cancel operational amplifier offset, then angle detection precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces expensive and complex chopper switches and chopper demodulators with a simpler, cheaper comparison-based offset cancellation circuit. The invention uses basic operational amplifiers in a feedback configuration with reference signal comparison, eliminating the need for specialized chopper components while maintaining precision.
Solution Approach 2:
The patent makes the operational amplifier perform multiple functions: signal amplification, offset cancellation, and error signal generation. By using the same amplifier in a feedback configuration with reference signal comparison, the system eliminates the need for separate dedicated offset cancellation circuits, reducing overall device complexity.
3Measurement precision
If multiple sensors and additional correction circuits are added to correct amplitude errors, then angle detection precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the amplitude correction function with the existing signal amplification and offset cancellation circuitry. The same feedback loop that cancels offset also performs amplitude correction by comparing the amplified signal with the reference signal, merging multiple correction functions into a single integrated circuit block rather than adding separate correction circuits.
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 enhances angle detection precision without increasing costs or errors, by directly correcting amplitude errors through drive voltage adjustments, thereby improving the accuracy and reliability of rotation angle measurements.
Implementation Method 1
a magnetic sensor is fixed closely to a rotating body to which a permanent magnet is provided
Data Source
AI summary
An angle detection device which includes multiple sensors to output multiple sinusoidal signals having different phases according to the rotation angle of a rotating body; a rotation calculation device to detect the rotation angle based on the multiple sinusoidal signals and detect an amplitude of the multiple sinusoidal signals to output the amplitude of the multiple sinusoidal signals as amplitude signal; and an amplitude comparison device to compare the amplitude signal with a predetermined amplitude target value and output an amplitude error signal indicating the comparison result; wherein the error of amplitude of the multiple sinusoidal signals is corrected by increasing or decreasing a drive input of a sensor driving unit based on the amplitude error signal.