Independent Wheel Torque Control for Same-Axle Electric Drive
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Solution Overview
Problem
Existing road vehicle control systems with independent motors on the same axle face inefficiencies in torque distribution, leading to suboptimal performance and stability, especially when driving on bends or uneven surfaces, due to the bond between angular speed differences and torque distribution.
Innovation Solution
A control method that independently adjusts torque to each wheel based on driver input and vehicle conditions, using an electronic control unit to calculate and distribute torque without regard to angular speed differences, incorporating sensors for attitude angle, yaw rate, and vertical forces to optimize performance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an electronically controlled self-locking differential is used to stabilize the vehicle during bending, then vehicle stability is improved, but torque distribution becomes suboptimal and performance is reduced
Solution Approach 1:
The patent replaces the mechanical self-locking differential system with an independent motor system for each wheel. Instead of using a physical differential mechanism with clutches to control torque distribution, the invention uses independent electric motors driven by a control unit to directly control torque delivery to each wheel based on detected vehicle conditions such as bending, slip, and vertical forces.
Solution Approach 2:
The control unit dynamically changes torque distribution parameters independently for each wheel based on real-time detection of vehicle conditions. During bending, the system detects the bend and adjusts torque to the inside and outside wheels differently, optimizing both stability and performance. The system also adjusts torque based on slip detection and vertical force variations, allowing continuous parameter optimization.
2Reliability
If torque is distributed based on angular speed difference through a differential mechanism, then wheel slip is reduced, but independence of torque control for each wheel is lost
Solution Approach 1:
The patent segments the drive system into independent motor units for each wheel. Instead of a single power source with a differential mechanism that couples wheel torques, each wheel has its own motor that can be controlled independently. This segmentation allows the control unit to deliver different torque values to each wheel based on individual wheel conditions, achieving both reliable slip control and maximum adaptability.
3Reliability
If a self-locking differential with clutch system is implemented, then torque transmission to slow-rotating wheels is improved, but device complexity increases
Solution Approach 1:
The patent eliminates the complex mechanical differential mechanism with clutch systems by substituting it with independent electric motors and an electronic control unit. The torque distribution function that previously required mechanical clutches and differential gears is now achieved through electronic control of independent motor torque output, significantly reducing mechanical complexity while maintaining or improving torque transmission reliability.
Data Source
AI summary
A method to control a road vehicle driven by a driver and provided with at least a first drive wheel and a second driver wheel belonging to a same axle, each drive wheel being independently operated by a respective first and second electric motor; the control method comprises the step of controlling the torque delivered by each respective motor to the first drive wheel or to the second drive wheel as a function of a torque requested by the driver and independently of the difference in angular speed between the first and the second wheel.