Inertial Sensor Signal Processing for Acceleration Separation
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Solution Overview
Problem
Conventional inertial sensors face challenges in accurately measuring motion acceleration due to the inclusion of gravitational acceleration, leading to significant measurement errors, especially when the object undergoes complex movements and posture changes.
Innovation Solution
A signal processing apparatus and inertial sensor configuration that extracts dynamic and static acceleration components from first and second detection signals, using a combination of piezoelectric and piezoresistive or electrostatic detection methods, allowing for accurate separation of motion acceleration from gravitational acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single acceleration sensor is used to detect acceleration, then the device complexity is low, but the measurement precision of motion acceleration deteriorates due to gravitational acceleration interference
Solution Approach 1:
The acceleration detection function is segmented into two specialized sensors: a first acceleration sensor that detects only dynamic acceleration components (AC waveform), and a second acceleration sensor that detects both dynamic and static acceleration components (AC+DC waveform). This segmentation allows each sensor to be optimized for its specific function, with the first sensor providing clean motion acceleration data and the second sensor providing gravitational acceleration data, thereby resolving the measurement precision issue without excessive complexity
Solution Approach 2:
The patent merges the outputs of two different acceleration sensors through signal processing. The dynamic acceleration component from the first sensor and the static acceleration component extracted from the second sensor are combined to produce the total acceleration measurement. This merging approach leverages the complementary strengths of both sensors to achieve high-precision motion acceleration measurement while maintaining a relatively simple overall device structure
2Measurement precision
If conventional acceleration sensors are used during complex movements, then the device structure remains simple, but the measurement precision deteriorates due to posture changes and gravitational acceleration
Solution Approach 1:
The system dynamically adapts to complex movements by using two sensors with different detection characteristics. The first sensor's AC-coupled design automatically filters out static gravitational components that vary with posture, while the second sensor's DC-coupled design tracks gravitational acceleration changes. This dynamic response allows accurate motion acceleration measurement regardless of object posture changes or complex movement patterns
Solution Approach 2:
The signal processing unit continuously processes signals from both sensors to separate dynamic and static acceleration components. By using the gravitational acceleration information from the second sensor as feedback, the system can compensate for posture changes and isolate the true motion acceleration from the first sensor, maintaining operational stability during complex movements
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 precise measurement of motion acceleration, improving detection accuracy and enabling stable posture detection with respect to the gravity direction, even during complex movements.
Implementation Method 1
detection means formed on the membrane and including a piezoelectric body
Implementation Method 2
piezoresistive elements respectively disposed at the root ends and tips of the plate-shaped bridge parts and that detects accelerations from the resistance variations of those piezoresistive elements
Implementation Method 3
an electrostatic device that includes a first electrode unit as a movable electrode and a second electrode unit as a fixed electrode and that detects a change in capacitance based on a change of a gap therebetween, to measure an acceleration
Data Source
AI summary
A signal processing apparatus according to an embodiment of the present technology includes an acceleration arithmetic unit. The acceleration arithmetic unit extracts, on a basis of a first detection signal and a second detection signal, the first detection signal including information related to an acceleration along at least a uniaxial direction and having an alternating-current waveform corresponding to the acceleration, the second detection signal including the information related to the acceleration and having an output waveform in which an alternating-current component corresponding to the acceleration is superimposed on a direct-current component, a dynamic acceleration component and a static acceleration component from the acceleration.