Vehicle Yaw Rate Control to Suppress Understeer and Wheel Slip

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Solution Overview

Problem

Existing vehicle control systems, such as those described in JP 2019-106786 A, enhance turning response by adding an additional control amount to the speed control amount, which can promote wheel slippage and increase the turning radius due to delayed response, particularly in electrically powered vehicles.

Innovation Solution

A vehicle control device that includes a target value setting unit, understeering determination unit, correction value calculation unit, and rotational speed control unit to adjust the rotational speeds of left and right driving motors based on a difference in wheel speeds and yaw rates, correcting the target vehicle speed and wheel speeds to prevent understeering and suppress slippage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the motors are controlled based on the additive control amount obtained by adding the additional control amount to the speed control amount to enhance turning response, then the turning response is enhanced, but wheel slippage is promoted and the turning radius increases

Engineering Contradiction:

Improveturning response speedVSAvoidvehicle stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The control device calculates a correction amount based on the difference between the actual yaw rate and the target yaw rate, and feeds this correction back to adjust the additive control amount. This feedback mechanism prevents excessive wheel slippage and maintains vehicle stability while preserving enhanced turning response.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the additive control amount by changing its parameter values based on the yaw rate deviation. When the deviation is large, a larger correction is applied; when the deviation is small, the correction is reduced. This parameter adjustment resolves the contradiction between rapid turning response and vehicle stability.

Inventive Principle:

Principle #35Parameter changes

2Speed

If the additive control amount is increased to enhance turning response, then the turning response is enhanced, but the turning radius increases due to delayed response

Engineering Contradiction:

Improveturning response speedVSAvoidturning radius

Core Design Contradiction:

SpeedVSLength of moving object

Solution Approach 1:

The correction amount is calculated based on the deviation between actual and target yaw rates, providing continuous feedback to adjust the additive control amount. This ensures the turning radius remains appropriate while maintaining enhanced turning response.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The additive control amount is made dynamic rather than fixed, adjusting in real-time based on the yaw rate deviation. This dynamic adjustment allows the system to achieve rapid turning response while preventing excessive turning radius expansion.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the vehicle speed is reduced to suppress wheel slippage, then wheel slippage is suppressed, but the turning response becomes slower

Engineering Contradiction:

Improvevehicle stabilityVSAvoidturning response speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

Instead of reducing vehicle speed, the system changes the parameter of the additive control amount based on yaw rate deviation. This allows the vehicle to maintain its speed and fast turning response while suppressing wheel slippage through intelligent control adjustment.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system replaces the mechanical approach of reducing vehicle speed with a control system approach that adjusts the additive control amount. This substitution maintains vehicle speed and turning response while achieving slippage suppression through electronic control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Speed

If the additive control amount is increased to enhance turning response, then the turning response is enhanced, but operational efficiency decreases due to increased slippage

Engineering Contradiction:

Improveturning response speedVSAvoidoperational efficiency

Core Design Contradiction:

SpeedVSProductivity

Solution Approach 1:

The feedback mechanism adjusts the additive control amount based on yaw rate deviation, preventing excessive wheel slippage that would reduce operational efficiency. This maintains both fast turning response and high operational efficiency.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes the additive control amount parameter to optimize both turning response and operational efficiency, preventing the efficiency loss that would result from excessive slippage.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12552454B2Vehicle control device, vehicle, and vehicle control method

Publication Date: 2026.02.17 HONDA MOTOR CO LTD

AI summary

A vehicle control device includes a target value setting unit that sets a target vehicle speed and a target yaw rate, a correction value calculation unit that calculates, in the case it is determined that the vehicle is in an understeering state, a correction value for correcting the target vehicle speed based on a deviation, a target vehicle wheel speed setting unit that sets target vehicle wheel speeds of a left driving wheel and a right driving wheel based on the target vehicle speed, the target yaw rate, and the correction value, and a rotational speed control unit that controls a rotational speed of the left driving motor based on the target vehicle wheel speed of the left driving wheel, and controls a rotational speed of the right driving motor based on the target vehicle wheel speed of the right driving wheel.