Multi-Axle Vehicle Controller for Independent Wheel Torque Distribution
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Solution Overview
Problem
Existing vehicle stability systems, such as ESC and AFS, are limited in their ability to independently drive and brake multiple axles, particularly in hybrid and electric vehicles, which restricts their capability to apply different driving and braking inputs to wheels, affecting stability and performance.
Innovation Solution
A vehicle with independently driven multiple axles, featuring a controller system that determines target control values for wheel steering, yaw moment, longitudinal force, and wheel speed, and independently drives wheels using in-wheel motors and brakes, allowing for different driving and braking inputs based on operation inputs and driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing vehicle stability systems (ESC, AFS) are used, then vehicle stability is maintained, but the ability to independently drive and brake multiple axles is limited
Solution Approach 1:
The vehicle is divided into multiple independently controllable axles, with each axle equipped with its own motor and brake system. This segmentation allows each axle to be controlled independently, enabling different driving and braking inputs to be applied to different wheels, thereby resolving the limitation of existing systems that cannot independently control multiple axles.
Solution Approach 2:
The vehicle system transitions from a static, unified control approach to a dynamic, multi-axis independent control approach. The controller continuously adjusts the driving and braking forces on each axle based on real-time vehicle state and driver input, allowing the system to adapt to changing conditions while maintaining stability.
2Productivity
If different driving and braking inputs are applied to wheels, then driving performance and stability are improved, but system complexity increases
Solution Approach 1:
The controller system is designed to perform multiple functions: it manages motor driving, brake application, steering control, and coordination between different axles. By creating a universal controller that handles all these functions, the system achieves improved driving performance without proportionally increasing complexity, as the same controller infrastructure is used for multiple purposes.
Solution Approach 2:
The controller acts as an intermediary between the driver's input and the multiple actuators (motors, brakes, steering systems). It processes the driver's intent and distributes appropriate commands to each axle and wheel, simplifying the overall system architecture by centralizing the coordination logic in a single control unit rather than requiring complex direct connections between all components.
3Ease of operation
If mechanical steering is used, then steering control is simple, but the vehicle cannot turn beyond mechanical limits
Solution Approach 1:
The system merges mechanical steering with independent wheel torque control. The mechanical steering mechanism provides the basic steering function, while the independent torque control on each wheel supplements this by applying differential forces to enable turning beyond the mechanical steering limits. This combination allows the vehicle to maintain simple mechanical steering operation while gaining enhanced turning capability.
Solution Approach 2:
The steering system uses a composite approach, combining mechanical steering components with electromagnetic torque control. Just as composite materials combine different materials to achieve superior properties, this composite steering system combines mechanical and electromagnetic systems to achieve both simplicity of operation and enhanced turning capability beyond mechanical limits.
Data Source
AI summary
A vehicle with independently driven multiple axles and a controller which independently drives the multiple axles are disclosed. The controller includes a first controller which determines a target control value including at least one of a mechanical steering angle of each of a plurality of wheels of a vehicle, a target yaw moment of the vehicle, a target longitudinal force of the vehicle, and a target wheel speed of each of the plurality of wheels; and a second controller which determines wheel torques of the plurality of wheels, which drive the plurality of wheels independently, based on the target control value, wherein the wheel torques of the plurality of wheels are different from one another.