Vehicle Traction Control Architecture for Faster Wheel Slip Response
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Solution Overview
Problem
Existing vehicle control systems experience control delays, leading to a need for more responsive slip rate control (traction control) in vehicles equipped with electrically-driven motors.
Innovation Solution
A travel control device for vehicles, featuring a main control unit that calculates a requested driving force based on driver input and vehicle behavior, and a sub control unit that controls driving and braking means to achieve target slip rates for each wheel, thereby enhancing responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a main control unit performs various calculations such as slip rate and calculates control amounts, then the control system can achieve comprehensive vehicle control, but control delay occurs reducing responsiveness
Solution Approach 1:
The control system is divided into a main control unit and sub control units. The main control unit performs comprehensive calculations for control accuracy, while sub control units execute specific control actions locally, reducing communication delays and improving responsiveness.
Solution Approach 2:
Target slip rates and target reference wheel speeds are pre-calculated by the main control unit and transmitted to sub control units in advance. This allows sub control units to immediately execute control actions without waiting for real-time calculations, reducing control delay.
2Productivity
If electrically-driven motors are used for driving wheels, then driving efficiency is improved, but control delay in the control unit reduces traction control responsiveness
Solution Approach 1:
The control architecture segments functions between main and sub control units. Electric motors respond to commands from sub control units that have pre-received target slip rate information, enabling rapid traction control response that matches the fast response capability of electric motors.
Solution Approach 2:
The system implements feedback control where sub control units continuously monitor actual wheel speeds and slip rates, compare them with target values, and adjust motor control in real-time. This closed-loop feedback ensures rapid and accurate traction control response.
Data Source
AI summary
A traction control device 50 for a vehicle including a front motor and a rear motor which drive wheels and a braking device provided to each of front and rear wheels on left and right includes a hybrid control unit 20 that calculates a requested driving force of the vehicle based on a driver request and a vehicle behavior and a control units 10 and 12 that controls the motors and the braking devices based on the requested driving force. The hybrid control unit 20 includes a reference wheel speed calculating part 52 that calculates a target reference wheel speed for each of the front and rear wheels on the left and right, and a target slip rate calculating/distributing part 54 that calculates a target slip rate of the wheels which is set relative to the target reference wheel speed. The control units 10 and 12 include a slip rate control part 62 that calculates an actual slip rate of the wheels and also controls each of the motors and the braking devices in a manner that the actual slip rate is controlled to be the target slip rate.