Drive Wheel Torque Distribution Using Real-Time Lookup Tables

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Solution Overview

Problem

Current methods for determining torque distribution in road vehicles with independent drive wheels, especially in high-performance electric vehicles, face challenges in optimizing energy efficiency and performance due to the complexity of calculations and the need for long computing times, which can lead to suboptimal solutions.

Innovation Solution

A method that uses a control unit to process various vehicle dynamics data, such as longitudinal speed, yaw rate, and attitude angle, to determine optimized torque distribution between front and rear axles, and between individual wheels, using pre-calculated tables to adjust electric motor torque distribution in real-time, maximizing lateral acceleration while ensuring stability and stationarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If real-time optimization of torque distribution is implemented using complex algorithms, then vehicle performance and energy efficiency are improved, but computing time and system complexity increase

Engineering Contradiction:
Improvevehicle performanceVSAvoidcomputing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent pre-calculates optimal torque distribution strategies offline and stores them in lookup tables before vehicle operation. During real-time driving, the control system simply retrieves pre-computed solutions based on current operating conditions (speed, acceleration, steering angle), eliminating complex real-time calculations while maintaining optimal performance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the continuous optimization problem into a discrete parameter selection problem by defining specific operating conditions (speed ranges, acceleration levels, steering angles) as discrete parameters. Each parameter combination maps to a pre-determined optimal torque distribution, converting complex continuous optimization into simple parameter-based lookup

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If complex algorithms are used to determine optimized torque distribution, then energy efficiency and performance are improved, but device complexity and implementation cost increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent performs complex optimization calculations offline during system development and stores results in lookup tables. The real-time control system only requires simple table lookup and interpolation operations, dramatically reducing computational complexity while maintaining optimal energy efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates simplified copies of the optimal torque distribution strategies in the form of lookup tables that replicate the behavior of complex optimization algorithms. These tabulated solutions approximate the continuous optimization problem with discrete pre-computed values, reducing computational burden

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4129785B1Method for determining an optimized torque distribution to the drive wheels of a road vehicle and relative road vehicle
Publication Date: 2025.03.26 FERRARI SPA
  • EP4129785B1 patent drawingFigure 1
  • EP4129785B1 patent drawingFigure 2
  • EP4129785B1 patent drawingFigure 3

AI summary

A method for determining an optimized torque distribution (AWDS, RLS, RLS') to the wheels (2, 3) of a road vehicle (1) comprising the steps of determining a table (ST) of distribution of the torque between a front axle (FA) and a rear axle (RA); determining a second table (ST") and a third table (ST‴) of distribution of the torque between a right wheel (2, 3) and a left wheel (2, 3) of the rear axle (RA) and of the front axle (FA), respectively; detecting the current longitudinal dynamics (Ax, Vx); using the first, the second and the third table (ST', ST", ST‴) to determine a current value of the first (AWDS), of the second (RLS) and of the third (RLS') distribution factor, respectively, based on the current longitudinal speed (Vx) and on the current longitudinal acceleration (Ax) of the road vehicle (1). Main figure: figure 8