Dump Truck Attitude Estimation Using Dual GPS and Road Gradient
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Solution Overview
Problem
Existing dump truck attitude estimation technologies using two position estimation devices, such as GPS, suffer from errors due to gyro-sensor and acceleration sensor inaccuracies, and require frequent maintenance, making it challenging to accurately estimate attitudes without additional sensors or stopping operations.
Innovation Solution
The solution involves setting two position estimation devices on a dump truck to calculate the gradient of the road and a contact point that minimizes rotational errors, using a gradient calculation unit to determine the attitude based on the contact point position and positions calculated by the two devices, allowing for accurate attitude estimation without extra sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two position estimation devices (GPS) are used to estimate dump truck attitude, then the system complexity is reduced, but measurement precision deteriorates due to inability to calculate rotational angle around the line connecting the two devices
Solution Approach 1:
The patent transforms the attitude estimation problem from directly calculating rotational angles to calculating the gradient of the road surface. By changing the parameter being measured (from attitude angles to road gradient), the system can accurately determine pitch and roll angles using only two GPS positions, resolving the measurement precision issue while maintaining low device complexity
Solution Approach 2:
The patent introduces a contact point on the road surface as an intermediary element. By calculating the gradient at this contact point and using it to determine the attitude, the system bridges the gap between limited GPS data and comprehensive attitude information, enabling accurate estimation without additional sensors
2Measurement precision
If inertial measurement units with gyro-sensors and acceleration sensors are used to estimate roll and pitch angles, then measurement precision is improved, but reliability deteriorates due to error accumulation from scale factors and biases during operation
Solution Approach 1:
The patent extracts the essential information needed for attitude estimation (position coordinates from GPS) and removes the problematic inertial sensors that cause error accumulation. By relying solely on position data and gradient calculation, the system eliminates scale factor and bias errors while maintaining measurement precision
Solution Approach 2:
The system uses the dump truck's own movement and position changes to naturally calculate the road gradient and attitude angles. By leveraging the truck's operational data rather than relying on separate calibration procedures, the system maintains reliability during continuous operation without requiring stopping or external correction
3Measurement precision
If three position estimation devices are used to estimate attitudes, then measurement precision is improved, but device complexity and maintenance cost increase due to greater number of sensors
Solution Approach 1:
The patent achieves accurate attitude estimation by changing from a three-device spatial configuration to a two-device configuration combined with gradient calculation. This parameter change in the estimation methodology allows the system to maintain measurement precision while reducing the number of required sensors
4Device complexity
If two position estimation devices are used without gradient calculation, then device complexity is reduced, but measurement precision deteriorates due to inability to determine rotational angle around the line connecting the devices
Solution Approach 1:
The patent introduces a new dimension of calculation by computing the gradient of the road surface. This additional computational dimension allows the system to derive complete attitude information (including rotational angles) from two-dimensional GPS position data, resolving the measurement precision limitation without adding sensors
Data Source
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AI summary
A dump truck includes a plurality of rear wheels (15) rotatably attached to a frame (11) and two GPS receivers (101, 102) arranged to be dislocated from each other in an anteroposterior direction of a vehicle. Any point selected from an area C, in the vehicle coordinates system B set in the dump truck, where the rear wheels contact a ground is defined as a reference point D. The two GPS receivers are arranged so that a vertical line descends from a line segment PQ, connecting two points P, Q of which positions are calculated by the two GPS receivers, to the reference point D. This makes it possible to accurately estimate an attitude of mining machinery by two position estimation means without stopping operation of the machinery.