In-Wheel Motor Braking Torque Control

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Solution Overview

Problem

Current traction and braking systems in electric and hybrid vehicles lack optimal modulation of dissipative and regenerative braking torques, limiting their control precision and effectiveness.

Innovation Solution

An electronic system that integrates In Wheel Motor or In Hub Motor technology with Brake By Wire systems, allowing independent control of dissipative and regenerative braking torques on each wheel through electric actuators, enabling continuous variation of braking torque and precise torque control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a hydraulic braking system is used in electric or hybrid vehicles with independent wheel control, then the system structure is simpler and easier to implement, but the braking torque modulation precision and control effectiveness deteriorate

Engineering Contradiction:
Improvesystem structureVSAvoidbraking torque modulation precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the traditional hydraulic braking system with an electric braking system. Each wheel is equipped with an electric motor that can independently control dissipative braking torque and regenerative braking torque. This substitution eliminates the limitations of hydraulic systems in torque modulation and enables precise independent control of braking forces on each wheel, directly resolving the contradiction between system simplicity and control precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If Brake By Wire systems are implemented to improve braking control precision, then wheel-by-wheel braking torque control is enhanced, but the system complexity increases and continuous torque variation capability is not fully realized

Engineering Contradiction:
Improvebraking torque control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the functions of dissipative braking and regenerative braking into a unified electric braking system. The electric motor serves dual purposes: applying dissipative braking torque through the braking mechanism and generating regenerative braking torque through electrical generation. This integration allows continuous variation of total braking torque by independently controlling both torque components, achieving precise wheel-by-wheel control without proportionally increasing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric motor in each wheel is designed to perform multiple functions: propulsion, dissipative braking, and regenerative braking. This multi-functionality allows the same component to provide continuous torque variation capability across different operating modes, enhancing braking control precision while avoiding the need for separate dedicated braking systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of energy

If independent control of dissipative and regenerative braking torque is implemented, then energy efficiency and vehicle control are improved, but the system complexity and control algorithm difficulty increase

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements feedback control mechanisms where the control unit continuously monitors wheel speeds, vehicle state, and braking torque requirements. Based on this feedback, the system dynamically adjusts the independent control of dissipative and regenerative braking torques to optimize energy recovery while maintaining safe and effective braking performance. This feedback approach manages control complexity through automated real-time optimization rather than requiring complex manual control algorithms.

Inventive Principle:
Principle #23Feedback

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

This system achieves enhanced braking control and energy efficiency by allowing continuous modulation of braking torque, improving vehicle stability, driveability, and energy savings by optimizing regenerative braking.

Implementation Method 1

controlling said at least one electric motor in regeneration mode to exert a regenerative braking torque on said at least one wheel

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

controlling said at least one electric actuator to exert a dissipative braking torque on said wheel

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 3

exert a dissipative braking torque on said wheel

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3532354B1Electronic system for controlling traction and braking of a vehicle and related method
Publication Date: 2022.01.26 FRENI BREMBO SPA
  • EP3532354B1 patent drawingFigure 1
  • EP3532354B1 patent drawingFigure 2
  • EP3532354B1 patent drawingFigure 3

AI summary

Electronic system (100) for controlling traction and braking of a vehicle (200), the vehicle (200) comprising at least one first wheel (R1), a first brake disc (DB1) operatively associated with said at least one first wheel (R1) and a first brake caliper (PZ1) able to be actuated to exert a dissipative braking torque on said first brake disc (DB), said at least one first wheel (R1) having a respective rotation axis (AR1), the system (100) comprising: at least one first traction and braking control unit (101); a device (102) for actuating braking operatively connected to said at least one first wheel (R1) of the vehicle (200), said device (102) for actuating braking also being operatively connected to said at least one first traction and braking control unit (101). The device (102) comprises: at least one first electric actuator (103) of the first brake caliper (PZ1 ), said at least first traction and braking control unit (101) being configured to control said at least one first electric actuator (103) to exert a dissipative braking torque on the first brake disc (DB1), through the first brake caliper (PZ1); at least one electric motor (104), having a respective rotation axis, operatively connected to said at least one first wheel (R1), the rotation axis of said at least one electric motor (104) coinciding with the rotation axis of said at least one first wheel (R1), said at least one first traction and braking control unit (101) being configured to control said at least one electric motor (104) in regeneration mode to exert a regenerative braking torque on said at least one first wheel (R1), said at least one first traction and braking control unit (101) being configured to control said at least one electric motor (104) in traction mode to exert a traction torque on said at least one first wheel (R1).