Vehicle Vertical Motion Estimation Using Suspension Friction Forces
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Solution Overview
Problem
Existing vehicle motion state estimation methods fail to accurately estimate vertical motion due to neglecting the impact of frictional forces acting in the front-rear and lateral directions of the wheel, especially during acceleration/deceleration and turning.
Innovation Solution
A vehicle motion state estimation device and method that include a vertical motion-caused wheel speed component estimation unit, a vertical force estimation unit, and a vertical motion estimation unit, which calculate and combine wheel speed components and frictional forces to accurately estimate vertical motion states, incorporating suspension geometry and sensor data from non-dedicated sensors like wheel speed, acceleration, and gyro sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vehicle dynamics model is used to estimate vertical motion state amount from general vehicle-mounted sensors, then dedicated vertical motion sensors can be avoided, but estimation accuracy deteriorates when frictional forces increase during acceleration/deceleration or turning
Solution Approach 1:
The invention changes the parameters considered in the vehicle dynamics model by explicitly incorporating frictional force parameters (Fx, Fy) and suspension geometry parameters (lever arms, angles) into the vertical motion estimation. This allows the system to account for the coupling between lateral/longitudinal friction and vertical motion through the suspension mechanism, thereby maintaining accuracy during acceleration and turning while still using only general vehicle-mounted sensors.
2Measurement precision
If frictional force and suspension geometry are taken into consideration in the estimation model, then vertical motion estimation accuracy improves under various conditions, but calculation complexity increases
Solution Approach 1:
The invention makes the existing wheel speed sensor and acceleration sensor data serve multiple functions: not only for basic vehicle state detection but also for calculating frictional forces and their vertical components through suspension geometry. By reusing existing sensor data for multiple purposes (detecting wheel speed, acceleration, and inferring friction effects), the system improves estimation accuracy without adding dedicated sensors or excessive complexity.
Solution Approach 2:
The system uses its own existing sensor measurements (wheel speed, acceleration) to self-calculate the frictional force effects and suspension geometry contributions. Rather than requiring external input or additional sensors, the estimation device processes its own measurement data through the enhanced model that includes friction and geometry parameters, enabling self-sufficient high-accuracy estimation.
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 estimation of vehicle vertical motion states under various conditions, including constant speed, acceleration/deceleration, and turning, by accounting for frictional forces, thereby improving accuracy and reliability.
Implementation Method 1
vertical force in which the frictional force acting in the front-rear direction or lateral direction of the wheel acts on the vehicle body due to the geometry of suspension
Data Source
AI summary
An object of the present invention is to provide a vehicle motion state estimation device and method that can estimate the vertical motion state amount with high accuracy by taking into consideration vertical force in which the frictional force acting in the front-rear direction or lateral direction of the wheel acts on the vehicle body due to the geometry of suspension. A vehicle motion state estimation device in a vehicle in which a wheel and a vehicle body are coupled via a suspension, the vehicle motion state estimation device including: a vertical motion-caused wheel speed component estimation unit that estimates a wheel speed component caused by vertical motion of the vehicle; a vertical force estimation unit that calculates vertical force in which frictional force of the wheel caused by motion of the vehicle acts on the vehicle body by geometry of the suspension; and a vertical motion estimation unit that estimates a state amount of vertical motion of a vehicle, in which the vertical motion estimation unit estimates a state amount of vertical motion of the vehicle based on a wheel speed component from the vertical motion-caused wheel speed component estimation unit and vertical force acting on the vehicle body from the vertical force estimation unit.