Roll Angle Determination Using Frequency Mixing and Low-Pass Filtering
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Solution Overview
Problem
Existing methods fail to effectively filter out non-linear interference signals from rotation sensors in a rotating shell, making it difficult to accurately calculate the roll angle due to moment interferences caused by the atmosphere and wind turbulence.
Innovation Solution
A method and device that mix down useful measurement signals to zero frequency and apply low-pass filtering, utilizing a phase-locking filter with sine and cosine operators, multipliers, and amplification regulators, along with a Δφ-eliminator to eliminate constant errors and noise, enabling smart non-linear filtration in a manageable frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear filters of the Kalman type are used to filter rotation sensor signals, then filtering capability is provided, but the method proves difficult to use for non-linear measurement signals
Solution Approach 1:
The patent transforms the non-linear filtering problem into a linear one by changing the parameter representation. Specifically, it uses a coordinate transformation where the non-linear measurement signals are converted into a different parameter space where linear Kalman filtering can be effectively applied. This allows the system to maintain reliability while improving ease of operation with non-linear signals.
2Device complexity
If rotation sensor signals are filtered directly without frequency transformation, then the filtering process is simpler, but non-linear interference signals from atmosphere and wind turbulence cannot be effectively separated
Solution Approach 1:
The patent introduces a frequency dimension transformation by mixing down the rotation sensor signals to a different frequency range before filtering. This dimensional change in the frequency domain allows the filtering process to effectively separate useful signals from non-linear interference caused by atmospheric and wind turbulence effects, achieving both signal separation accuracy and manageable process complexity.
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 effectively separates useful signals from interference, allowing for accurate estimation of the roll angle with reduced noise and constant errors, improving the determination of the roll angle in rotating bodies.
Implementation Method 1
a useful measurement signal in the sensors' rotation signals is mixed down to zero in frequency
Implementation Method 2
the rotation signals are thereafter low-pass filtered
Implementation Method 3
utilizing a phase-locking filter with sine and cosine operators, multipliers, and amplification regulators
Data Source
AI summary
The invention relates to a method and device for the determination of the roll angle φ of a rotating body, such as a shell, utilizing sensors for the detection of rotation signals in a body-fixed coordinate system. According to the invention, a new filter device is proposed to handle moment interferences to which the body is subjected, for example, caused by wind turbulence in the atmosphere or similar phenomena. The interferences are eliminated by useful measurement signals emitted by the sensors being mixed down to the frequency zero and by the sensors' rotation signals thereafter being low-pass filtered.