Electric Axle Drive Steering Compensation for Motor Torque Imbalance
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Solution Overview
Problem
Existing electric axle drive trains with separate electric motors for each vehicle wheel lack a differential gear, leading to potential vehicle swerving and safety risks in case of motor failure due to unbalanced torque.
Innovation Solution
An electrically operable axle drive train with a control unit that compensates for unbalanced torque by actuating the steering system to counteract the torque, using existing steering system components, ensuring safe vehicle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate electric motors are used for each vehicle wheel, then the drive train becomes more flexible and compact, but vehicle stability deteriorates in case of motor failure due to unbalanced torque
Solution Approach 1:
The steering system acts as an intermediary component to compensate for torque imbalance caused by electric motor failure. The control unit calculates the torque difference and actuates the steering system to generate a counteracting torque, thereby maintaining vehicle stability without requiring additional drive train components.
Solution Approach 2:
The steering system is made multi-functional by using it not only for directional control but also for compensating drive train torque imbalance. This allows the existing steering components to serve a dual purpose: normal steering operations and stability compensation during motor failure, avoiding the need for dedicated stability control hardware.
2Device complexity
If no differential gear is integrated in the drive train, then the drive train structure is simplified, but torque distribution becomes unbalanced leading to vehicle swerving
Solution Approach 1:
The mechanical differential gear is replaced by an electronic control system that actuates the steering system. Instead of using mechanical components to distribute and balance torque, the patent uses electronic sensing of torque imbalance and electronic actuation of steering components to achieve the same stability effect, thereby simplifying the mechanical drive train structure.
3Extent of automation
If driver intervention is required to correct vehicle swerving, then the driver maintains control awareness, but response time is delayed and safety is compromised
Solution Approach 1:
The control unit continuously monitors the operation of electric machines and detects torque imbalance in real-time. Upon detecting a malfunction, the system automatically calculates the required compensation and actuates the steering system without delay, providing immediate feedback control to maintain vehicle stability and prevent dangerous swerving.
Solution Approach 2:
The control system is pre-programmed with the logic to detect motor failure and calculate the appropriate steering compensation. When a malfunction occurs, the system immediately executes the pre-planned compensation action without requiring driver interpretation or decision-making, ensuring the fastest possible response to maintain safety.
Data Source
AI summary
An electrically operable axle drive train for a motor vehicle, comprising a first vehicle axle having a first electric machine configured to drive a first vehicle wheel of the first vehicle axle, a second electric machine configured to drive a second vehicle wheel of the first vehicle axle, a steering system configured to steer the motor vehicle, and a control unit designed to actuate the steering system. In response to a malfunction of one of the electric machines in which at least one of a lower speed and a lower torque is applied to one of the vehicle wheels than to the other vehicle wheel, the control unit actuates the steering system to a steering position that counteracts a resulting torque that acts on the motor vehicle in response to the malfunction.