Earthmoving Blade Slope Control via Gyroscope-Tilt Sensor Fusion
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Solution Overview
Problem
Existing automatic blade slope control systems for earthmoving machines face challenges in accurately and quickly adjusting blade slope angles during dynamic operations due to the limitations of tilt sensors, which exhibit slow response times and errors under high dynamic motions.
Innovation Solution
Combining three-axis gyroscopes with tilt sensors to provide accurate and fast attitude measurements, and using proportional-derivative control algorithms to enhance the precision and speed of blade slope angle control, while accounting for sensor synchronization and potential errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If tilt sensors are used for blade slope angle measurement, then the system structure is simple, but the response time is slow and measurement accuracy deteriorates under high dynamic motions
Solution Approach 1:
The patent combines tilt sensors with three-axis gyroscopes into a hybrid measurement system. The tilt sensors provide accurate static measurements while gyroscopes capture dynamic motion information. By merging these complementary sensor types, the system achieves both structural simplicity and high measurement accuracy under dynamic conditions.
Solution Approach 2:
The measurement system uses a composite sensing approach, integrating different sensor technologies (tilt sensors and gyroscopes) with complementary characteristics. This composite sensor system leverages the strengths of each sensor type to overcome their individual limitations in dynamic environments.
2Device complexity
If tilt sensors are used for blade slope angle measurement, then the system cost is low, but the response speed is slow
Solution Approach 1:
The system merges tilt sensors (cost-effective) with three-axis gyroscopes (fast response) to create a hybrid measurement system. This combination allows the system to maintain low overall cost while achieving fast response speeds through the gyroscope component during dynamic operations.
Solution Approach 2:
The system dynamically switches between or combines measurements from tilt sensors and gyroscopes based on the operational state. During high-dynamic motions, the gyroscope data is prioritized for fast response, while tilt sensor data is used during static or low-dynamic conditions to maintain cost-effectiveness.
3Device complexity
If measurements from tilt sensors and three-axis gyroscope are fused without considering time sequence, then the processing is simple, but the control accuracy deteriorates due to sensor asynchronization
Solution Approach 1:
The system performs preliminary time synchronization and sequencing of measurements from tilt sensors and gyroscopes before fusion. By pre-processing the temporal alignment of data, the system ensures accurate correspondence between sensor readings without requiring complex real-time synchronization algorithms during control processing.
Solution Approach 2:
The system uses feedback mechanisms to track and compensate for temporal offsets between sensor measurements. By continuously monitoring the time sequences and adjusting the fusion process accordingly, the system maintains high accuracy while managing processing complexity through adaptive correction.
4Speed
If all sensor measurements are fused continuously, then the control responsiveness is high, but the reliability deteriorates due to invalid measurements from mechanical disturbances
Solution Approach 1:
The system extracts and identifies invalid measurements from mechanical disturbances by monitoring sensor data quality indicators. When disturbances are detected, the problematic measurements are separated and excluded from the fusion process, preventing them from degrading control reliability while maintaining continuous control responsiveness with valid data.
Solution Approach 2:
The system converts the harmful effect of mechanical disturbances into a detectable signal that triggers measurement validation. By using the disturbance characteristics themselves as indicators of invalid data, the system turns potential harm into a useful mechanism for identifying and filtering unreliable measurements, thereby maintaining both responsiveness and reliability.
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 combination improves the accuracy and speed of blade slope angle control, maintaining stability and accuracy even under high dynamic conditions, enabling more precise and efficient earth shaping operations.
Implementation Method 1
Combining three-axis gyroscopes with tilt sensors to provide accurate and fast attitude measurements
Implementation Method 2
two tilt sensors mounted on the blade. Measurements from the two tilt sensors include a blade slope angle and a blade tip angle
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The slope angle of a blade on an earthmoving machine is automatically controlled based on measurements from a three-axis gyroscope, a blade slope angle tilt sensor, and a blade tip angle tilt sensor mounted on the blade. A three-axis gyroscope has high dynamic response and high resistance to mechanical disturbances but is subject to potentially unbounded errors. A tilt sensor has bounded errors but has a slow dynamic response and a high sensitivity to mechanical disturbances. The combination of a three-axis gyroscope and two tilt sensors provides an advantageous measurement system. Algorithms for performing proper fusion of the measurements account for the lack of synchronization between the three-axis gyroscope and the tilt sensors and also screen out invalid measurements from the tilt sensors. The blade slope angle is controlled based on a reference blade slope angle and an estimate of the blade slope angle computed from properly fused measurements.