Vehicle Motion Control via Dynamic Force Distribution
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Solution Overview
Problem
Existing vehicle motion control systems face challenges in improving turning performance and stability, particularly in vehicles with front-rear twin motor arrangements, as they often result in high costs and weight due to the need for additional motors, and struggle to effectively distribute driving and braking forces to enhance maneuverability and stability.
Innovation Solution
A method and device for controlling the distribution of driving and braking forces between the front and rear wheels, known as D+, which adjusts the distribution ratio based on lateral jerk and yaw angular acceleration to optimize steering characteristics, maneuverability, and stability by dynamically distributing the forces during acceleration and deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If left-right twin motor arrangement is used to eliminate differential gear and enable DYC, then device complexity is reduced, but vehicle stability deteriorates due to roll moment generation from imbalance between left and right link half forces
Solution Approach 1:
The invention segments the force distribution control into front-rear wheel distribution and left-right wheel distribution. The front-rear distribution control system manages the primary driving force allocation between axles, while the left-right distribution control system handles yaw moment control, separating stability-critical functions from maneuverability functions.
Solution Approach 2:
The invention applies different control strategies to different wheel pairs: front-rear wheels receive load-proportional distribution for stability, while left-right wheels receive DYC-based distribution for maneuverability. This local differentiation allows each axis to optimize its contribution to overall vehicle performance.
2Reliability
If front-rear twin motor arrangement is used with dynamic distribution control, then maneuverability and stability are improved, but device complexity and cost increase due to requiring multiple motors and control systems
Solution Approach 1:
The control device performs multiple functions: it manages front-rear driving force distribution, left-right driving force distribution, oversteer correction, and understeer correction. This multi-functionality consolidates what would otherwise require separate systems into a single integrated control unit.
Solution Approach 2:
The invention merges the front-rear distribution control system and left-right distribution control system into a unified control architecture that coordinates both distribution strategies simultaneously, reducing overall system complexity compared to having completely separate systems.
3Ease of operation
If left-right twin motor arrangement performs DYC during turning, then maneuverability is improved, but energy regeneration efficiency deteriorates because inner wheel operates at lower voltage than outer wheel
Solution Approach 1:
The invention dynamically adjusts the distribution ratio based on real-time vehicle state (lateral acceleration, yaw rate, steering angle). During regenerative braking, it optimizes the balance between maintaining DYC effectiveness and maximizing energy recovery by adapting force distribution to current operating conditions.
Solution Approach 2:
The control device changes the distribution ratio parameter dynamically based on vehicle state. During turning with regenerative braking, it adjusts the ratio to optimize both the voltage match for energy recovery and the yaw moment generation for maneuverability.
4Weight of moving object
If conventional four-wheel drive with one prime mover is used, then cost and weight are reduced, but maneuverability and stability during turning deteriorate compared to twin motor arrangements
Solution Approach 1:
The invention replaces mechanical differential gear mechanisms with electronic control of motor torque distribution. The control device calculates optimal force distribution ratios and commands individual motor torques, substituting mechanical complexity with electronic control to achieve superior turning performance with a single prime mover.
Solution Approach 2:
The system dynamically adjusts driving force distribution between front and rear wheels based on real-time vehicle state parameters (lateral acceleration, yaw rate, steering angle), enabling adaptive optimization of turning performance without requiring additional mechanical components.
Data Source
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AI summary
The purpose of the present invention is to provide a device and method for controlling vehicle motion and a vehicle equipped with the device, such that driving force and/or braking force is properly distributed between front wheels and rear wheels so that steering characteristics are made suitable and and controllability and stability improve. This device comprises a means for controlling braking and/or driving force distribution between the front wheels and rear wheels of a vehicle such that when the absolute value of lateral acceleration of the vehicle increases, the distribution to the front wheels is made smaller, and when the absolute value of lateral acceleration of the vehicle decreases, the distribution to the front wheels is made larger.