Vehicle Wheel Slip Angle Estimation via Road Surface Tilt Correction
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Solution Overview
Problem
Dump trucks face challenges in accurately estimating the slip angle of their vehicle wheels due to the tilting of the vehicle body caused by heavy payloads, which affects the accuracy of measurements from Inertial Measurement Units (IMUs) assuming a parallel vehicle body and road surface.
Innovation Solution
A device comprising a vehicle-body IMU, road-surface distance measurement device, wheel speed measurement device, and steering angle measurement device, along with an attitude-toward-road-surface estimation section, on-road-surface inertia quantity calculation section, and wheel slip angle estimation section, converts vehicle-body coordinate systems to road-surface coordinate systems to accurately determine the slip angle of vehicle wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the vehicle body is mounted on vehicle wheels via suspensions to handle heavy payloads, then the load-bearing capability is improved, but the vehicle body tilts with respect to the road surface, making accurate slip angle measurement difficult
Solution Approach 1:
The patent introduces road surface distance measurement devices as intermediaries to measure the actual distance between the vehicle body and road surface. This measurement serves as a mediator to calculate the tilt angle, which is then used to correct the slip angle measurement from the IMU, resolving the contradiction between load-bearing capability and measurement accuracy
Solution Approach 2:
The patent changes the reference parameter for slip angle calculation from assuming a parallel vehicle body to using the actual tilt angle measured by distance sensors. By dynamically adjusting the coordinate transformation parameters based on measured distances, the system maintains accurate slip angle measurement despite vehicle body tilting under heavy loads
2Device complexity
If the assumption that the vehicle body is parallel to the road surface is used to simplify calculations, then the calculation process is simplified, but the slip angle calculation becomes inaccurate when the vehicle body tilts due to suspensions contracting under heavy loads
Solution Approach 1:
The patent performs preliminary measurement of the distance between the vehicle body and road surface using dedicated sensors before calculating the slip angle. This preliminary action of measuring the actual geometry allows the system to pre-calculate the tilt angle and establish the correct coordinate transformation, simplifying the subsequent slip angle calculation while ensuring accuracy
Solution Approach 2:
The patent replaces the mechanical assumption of parallelism with an optical/electronic measurement system. Instead of assuming the vehicle body is parallel to the road surface, the system uses light-based or electromagnetic distance measurement devices to detect the actual geometry, substituting a simple assumption with a precise measurement-based approach
Data Source
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AI summary
An device of estimating slip angle of vehicle wheel comprises an attitude-toward-road surface estimation section 121 that uses a series of distances to measurement points on a road surface to estimate vehicle-body-road-surface coordinate conversion information(VCCI) for conversion from a vehicle-body coordinate system to a road-surface coordinate system ,an on-road-surface inertia quantity calculation section 122 that removes a gravity acceleration component from the vehicle-body inertia quantity to obtain inertia quantity caused by motion of a vehicle body 103 and uses the VCCI to convert from the inertia quantity caused by the motion of the vehicle body 103 to the road-surface coordinate system, and a wheel slip angle estimation section 123 that a wheel velocity vector along an inclination direction of the vehicle and a wheel acceleration, and estimates a sideslip angle of the vehicle wheel on the basis of a difference between the wheel acceleration vector and the acceleration vector converted to the road-surface coordinate system.