Vehicle Drive Device Torque Control for Split-Mu Road Slippage
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Solution Overview
Problem
Existing vehicle drive systems struggle to transmit adequate driving torque and braking torque to split-μ roads with different friction levels on either side of a vehicle, leading to reduced driving performance and unnecessary deceleration.
Innovation Solution
A vehicle drive device with left and right electric motors and a controller that adjusts torque by decreasing the power drive torque on the slipping wheel and increasing it on the opposing wheel, or vice versa, to maintain optimal torque transmission and reduce yaw moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque of the drive motor is reduced when wheel slippage is detected, then wheel slippage is suppressed, but the total drive torque transmitted to the road surface is reduced, causing unnecessary deceleration
Solution Approach 1:
The patent segments the torque control into left and right wheel-specific control. Instead of uniformly reducing torque to both wheels when slippage is detected, the system independently controls torque distribution to each wheel based on individual slippage detection, allowing torque to be reduced only where necessary while maintaining torque on the non-slipping wheel
Solution Approach 2:
The patent applies local quality by implementing asymmetric torque control where the left and right wheels receive different torque adjustments based on their individual slippage conditions. The torque change amount is specifically applied to the wheel experiencing slippage while the opposite wheel receives compensating torque to maintain total drive torque
2Reliability
If the torque command value is uniformly reduced when either left or right wheel slippage is detected, then slippage is controlled, but the drive torque appropriate for driver demands cannot be transmitted on split-μ roads
Solution Approach 1:
The patent implements local quality by applying different torque control strategies to the left and right wheels based on their individual slippage conditions and the road friction characteristics. This allows the system to adapt to split-μ road conditions where each side of the vehicle experiences different friction levels
Solution Approach 2:
The patent applies dynamics by continuously adjusting the torque distribution between left and right wheels based on real-time slippage detection and road conditions. The torque change amounts are dynamically modified based on the operation amount of the accelerator pedal and the detected slippage conditions
Data Source
AI summary
When both a left rear wheel and a right rear wheel are driven by first and second electric motors, and acceleration slippage occurs at either the left wheel or the right wheel, the acceleration slippage is reduced by decreasing the command motor torque (power drive torque) of the first or second electric motor connected to the wheel at which acceleration slippage was generated. The command motor torque of the first or second electric motor connected to the other wheel (wheel on the other side) on the right or left side that is opposite the wheel at which slippage occurred is increased, thereby making it possible to supplement the decrease in the driving torque of the wheel at which slippage occurred.