Vehicle Load-Aware Control for Overturning Prevention
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Solution Overview
Problem
Existing vehicle control systems fail to accurately account for the shifting center of gravity and varying wheel loads due to load positioning, leading to inadequate overturning prevention control, especially during changes in tire characteristics and vehicle speed.
Innovation Solution
A vehicle control device that includes a motion condition detector, wheel load acquisition unit, loading state acquisition unit, and controller to calculate inertia values and adjust braking/driving forces based on wheel loads and motion conditions to prevent overturning, using an inertia tensor and threshold values to manage load differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque control based on pitch angular acceleration is used, then longitudinal overturning prevention is achieved, but lateral overturning prevention and center-of-gravity shifting effects are not considered
Solution Approach 1:
The control system is divided into independent control modules for longitudinal overturning prevention and lateral overturning prevention, each handling specific rotational motions (pitch and roll respectively). This segmentation allows each module to focus on its specific function while the overall system achieves comprehensive coverage of all rotational motions.
Solution Approach 2:
The control device is designed to perform multiple functions by calculating control amounts for both longitudinal and lateral overturning prevention simultaneously. The system universally handles pitch motion (longitudinal) and roll motion (lateral) through a unified control framework that considers all rotational motions and center-of-gravity shifting effects.
2Device complexity
If reference turning model with constant vehicle speed is used, then lateral overturning control is simplified, but accuracy decreases during acceleration/deceleration
Solution Approach 1:
The control system transitions from a static reference model (constant speed) to a dynamic model that adapts to changing vehicle conditions. By incorporating acceleration and deceleration effects into the lateral overturning prevention control, the system dynamically adjusts to match actual vehicle behavior during speed changes, maintaining accuracy without excessive complexity.
Solution Approach 2:
The control amounts are adjusted based on changing vehicle parameters such as acceleration, deceleration, and loading state. By modifying control parameters dynamically according to actual motion conditions, the system maintains precision across varying operating conditions without requiring an overly complex model structure.
3Adaptability or versatility
If load is not positioned at center axis, then loading flexibility is improved, but roll and yaw behaviors affect pitch behavior control accuracy
Solution Approach 1:
The control system explicitly accounts for asymmetric loading conditions where the load center does not coincide with the vehicle center axis. By incorporating roll and yaw behavior calculations into the pitch control framework, the system handles asymmetric weight distribution accurately, maintaining pitch control precision regardless of loading position flexibility.
Solution Approach 2:
The control device acts as an intermediary that coordinates between different rotational motions (roll, yaw, and pitch). By calculating control amounts that consider the coupled effects of all three motions, the system mediates the interaction between lateral and longitudinal stability, ensuring accurate pitch control even when asymmetric loading causes coupled motion behaviors.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A vehicle control device including a motion condition detector (22) detecting motion conditions including a rotational motion and a longitudinal acceleration of a vehicle (1) on which a load is to be loaded, a wheel load acquisition unit (32) acquiring wheel loads of wheels, a loading state acquisition unit acquiring a loading state of the load loaded on the vehicle (1), an inertia value calculator calculating an inertia value including principal axes of inertia about a center of gravity of the vehicle (1) with the load included, based on the acquired loading state, and a controller performing overturning prevention control that suppresses an increase in difference between the wheel loads of front and rear wheels of the vehicle (1), using the acquired wheel loads of the wheels, the inertia value, and detection values of the motion conditions.