Vehicle Wheel Torque Control Under Motor Protection Limits

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Solution Overview

Problem

Existing vehicle control systems face challenges in maintaining wheel operation stability when encountering obstacles or uneven road surfaces, as the electric motor's protection control restricts current supply, leading to insufficient torque and potential vehicle disturbance.

Innovation Solution

A vehicle control device comprising an acquisition unit, a situation determination unit, and a suppression unit that acquires traveling environment information, determines if a disturbance is present, and suppresses the protection control's current restriction in such situations, allowing the electric motor to generate sufficient torque to resist disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If protection control restricts current supply to the electric motor, then the electric motor is protected from overheating, but the torque generated by the electric motor becomes insufficient to resist disturbances

Engineering Contradiction:
Improveprotection of electric motorVSAvoidtorque
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The protection control is made dynamic by temporarily suspending it when disturbances are detected. The control unit monitors wheel operation changes and selectively disables protection control only during disturbance events, allowing full current and torque output when needed, while restoring protection control when normal conditions resume. This dynamic adjustment resolves the contradiction between motor protection and torque availability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the current restriction parameter based on operating conditions. During normal operation, protection control applies current restrictions to prevent overheating. When disturbances are detected through wheel operation monitoring, the system changes the current parameter to allow unrestricted supply, enabling maximum torque generation to counteract the disturbance.

Inventive Principle:
Principle #35Parameter changes

2Force

If larger current is supplied to the electric motor to generate larger torque for resisting obstacles, then the torque is sufficient to maintain wheel operation, but overheating is more likely to occur

Engineering Contradiction:
ImprovetorqueVSAvoidtemperature of electric motor
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The system applies protection control periodically during normal operation to prevent overheating, but temporarily suspends it during disturbance events. This periodic application of protection control allows the motor to operate at full power when needed while preventing cumulative overheating during normal operation, resolving the contradiction between torque generation and temperature control.

Inventive Principle:
Principle #19Periodic action

3Reliability

If protection control is executed to prevent overheating, then the electric motor is protected, but the wheel operation may be changed by disturbances

Engineering Contradiction:
Improveprotection of electric motorVSAvoidwheel operation stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system uses feedback from wheel operation monitoring to detect disturbances. The control unit continuously monitors wheel operation and compares it against expected values. When deviations indicating disturbances are detected, the feedback loop triggers suspension of protection control to allow adequate torque for maintaining wheel operation stability, thus resolving the contradiction between motor protection and operational stability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4570568A1Vehicle control device
Publication Date: 2025.06.18 TOYOTA JIDOSHA KK
  • EP4570568A1 patent drawingFigure 1
  • EP4570568A1 patent drawingFigure 2
  • EP4570568A1 patent drawingFigure 3

AI summary

A vehicle control device (10) includes an acquisition unit (111) configured to acquire traveling environment information (Je) of a vehicle (1), a situation determination unit (112) configured to determine whether or not a predetermined situation where a disturbance acts on a wheel (3) such that an operation is changed has occurred, based on the traveling environment information (Je), and a suppression unit (113) configured to suppress restriction of protection control of protecting an electric motor by restricting a current supplied to the electric motor, in a case where the predetermined situation has occurred.