IMU Retrofit for Linkage Angle Measurement
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Solution Overview
Problem
Current methods for measuring the linkage angle between a vehicle body and an implement, such as those using rotary position sensors, are less accurate and flexible compared to inertial measurement unit (IMU) sensors, necessitating the development of systems and methods for installing or retrofitting IMUs to improve measurement accuracy.
Innovation Solution
The method involves installing multiple IMUs on a machine, calibrating their orientation, obtaining measurements, determining relative differences, and processing these using a Kalman filter procedure to calculate the relative position between the machine body and implement, allowing for flexible installation and potential replacement of existing sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotary position sensors are used to measure linkage angle, then the system is simple and easy to install, but the measurement accuracy is insufficient
Solution Approach 1:
The patent divides the measurement system into multiple independent IMU sensors positioned at different locations (chassis, tilt lever, lift arm). Each sensor independently measures local orientation, and the results are combined through relative difference calculation to determine the overall linkage angle. This segmentation allows high-precision measurement while maintaining modular system architecture that simplifies installation.
Solution Approach 2:
The patent replaces traditional rotary position sensors (mechanical contact-based measurement) with IMU sensors (inertial measurement technology). The IMUs use accelerometers and gyroscopes to detect orientation changes, eliminating mechanical linkages and contact wear, thereby achieving higher precision without significant complexity increase.
2Measurement precision
If IMU sensors are installed on multiple components to improve measurement accuracy, then the measurement precision improves, but the installation complexity increases
Solution Approach 1:
The patent makes the IMU sensor system universal by allowing installation on any component with known relative positioning. The same sensor type and processing method can be applied to different locations (chassis, tilt lever, lift arm, bucket) without requiring location-specific hardware modifications. This multi-functionality simplifies installation while enabling high-precision measurement through flexible sensor placement.
Solution Approach 2:
The patent introduces relative difference calculation as an intermediary step between individual sensor measurements and the final position determination. By calculating the difference between measurements from different locations and using Kalman filtering, the system eliminates the need for complex direct positioning mechanisms, simplifying installation while maintaining accuracy.
3Measurement precision
If existing linkage angle sensors are retrofitted with IMUs, then the measurement accuracy improves, but the retrofitting process becomes more complex
Solution Approach 1:
The patent performs preliminary calibration of the IMU sensors before installation, establishing the orientation relationship between sensors at different locations. This preliminary action simplifies the actual retrofitting process by pre-determining the geometric relationships needed for accurate measurement, eliminating the need for complex real-time calibration during installation.
Solution Approach 2:
The patent changes the measurement parameters from direct position measurement (rotary sensors) to orientation measurement (IMU angles). By measuring orientation changes rather than direct position, the system can retrofit existing mechanical linkages without requiring precise geometric knowledge of the linkage itself, simplifying the retrofitting process while maintaining measurement accuracy.
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 the accuracy of linkage angle measurements by using IMUs, providing a flexible and effective method for retrofitting existing systems with improved positional data processing, reducing noise and drift in sensor data.
Implementation Method 1
The first measurement includes a first acceleration, a first angular velocity, and a first gravity-based pitch angle
Implementation Method 2
a first gravity-based pitch angle, and the second measurement includes a second acceleration, a second angular velocity, and a second gravity-based pitch angle
Implementation Method 3
processing the relative differences using a Kalman filter procedure to determine positional data of the machine
Data Source
AI summary
A method for retrofitting a plurality of position sensors on a machine includes installing the plurality of position sensors on the machine, wherein the position sensors include at least two inertial measurement units (IMUs). The method further includes calibrating orientation of the IMUs, obtaining measurements from the IMUs, determining relative differences between the measurements obtained from the IMUs, and processing the relative differences using a Kalman filter procedure to determine positional data of the machine.