Vehicle Load-Aware Overturning Control Using Wheel Load Distribution
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Solution Overview
Problem
Conventional vehicle control systems fail to effectively perform overturning prevention control, especially when the load is not centered over the wheels, leading to issues with precise control due to shifting center of gravity and discrepancies in tire characteristics during deceleration, resulting in inadequate controllability.
Innovation Solution
A vehicle control device that includes a motion condition detector, wheel load acquisition unit, loading state acquisition unit, and an inertia value calculator to calculate principal axes of inertia about the center of gravity, enabling the controller to suppress differences in wheel loads between wheels, thereby preventing overturning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque control is used based on pitch angular acceleration and center of gravity position, then longitudinal overturning prevention is achieved, but lateral overturning control precision deteriorates when load center shifts occur
Solution Approach 1:
The patent segments the overturning prevention control into two independent control systems: longitudinal overturning prevention based on pitch angular acceleration and center of gravity position, and lateral overturning prevention based on roll angular acceleration and load center shift detection. This segmentation allows each control system to optimize for its specific direction without interference from the other, resolving the precision loss that occurs when load center shifts affect lateral control.
Solution Approach 2:
The patent introduces wheel load detection as an intermediary measurement system that directly detects load distribution on individual wheels. This intermediary provides accurate real-time data about actual weight distribution, which serves as a feedback mechanism to precisely determine center of gravity position and load center shift, thereby improving measurement precision for both longitudinal and lateral control systems.
2Ease of operation
If reference turning model is used for lateral overturning prevention, then constant speed turning control is achieved, but controllability deteriorates during deceleration when tire characteristics change
Solution Approach 1:
The patent transitions from a static reference turning model valid only at constant speed to a dynamic control system that adapts to varying vehicle states. The lateral overturning prevention controller continuously adjusts control forces based on real-time detection of roll angular acceleration, vehicle speed, and deceleration rate, enabling reliable control across all operating conditions including deceleration where tire characteristics change.
Solution Approach 2:
The patent implements a feedback control mechanism where the lateral overturning prevention controller continuously monitors actual vehicle behavior (roll angular acceleration, wheel loads) and adjusts control forces accordingly. This feedback loop allows the system to compensate for changing tire characteristics during deceleration and maintain reliable controllability, unlike the open-loop reference model approach.
3Device complexity
If simple torque control based on pitch acceleration is used, then control system complexity is reduced, but lateral overturning prevention precision deteriorates
Solution Approach 1:
The patent segments control functions into distinct longitudinal and lateral control modules. The longitudinal module handles pitch-based overturning prevention with simpler logic, while the lateral module independently handles roll-based overturning prevention with specialized detection and control algorithms. This segmentation allows each module to be optimized for its specific function without requiring the other's complexity, achieving precise lateral control while maintaining overall system manageability.
Solution Approach 2:
The patent enables the lateral overturning prevention system to self-adjust based on detected load center shift and wheel load distribution. The system automatically determines the appropriate control forces needed to prevent lateral overturning without requiring complex external calculation or intervention, achieving precise lateral control through self-service mechanisms that adapt to actual loading conditions.
Data Source
AI summary
A vehicle control device including a motion condition detector detecting motion conditions including a rotational motion and a longitudinal acceleration of a vehicle on which a load is to be loaded, a wheel load acquisition unit acquiring wheel loads of wheels, a loading state acquisition unit acquiring a loading state of the load loaded on the vehicle, an inertia value calculator calculating an inertia value including principal axes of inertia about a center of gravity of the vehicle 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, using the acquired wheel loads of the wheels, the inertia value, and detection values of the motion conditions.