Four-Wheel Steering Torque Distribution via Driving Motor Coordination
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Solution Overview
Problem
In vehicle steering systems with motor-driven power steering (MDPS), there is a spatial limitation in increasing the capacity and magnitude of the steering motor to generate sufficient torque for full turns when the vehicle is stopped, especially at high steering angles, due to the need for both driving and steering motors in four-wheel independent systems.
Innovation Solution
An apparatus that includes a turning direction recognizer and a tire driving controller to apply driving forces to specific tires to assist steering torque, using a combination of first and second driving forces to generate a steering assisting torque that supplements the steering motor's limit, maintaining the vehicle's forward/rearward force at 0, thereby reducing the need for increased steering motor capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the capacity and magnitude of the steering motor are increased to generate sufficient torque for full turns when the vehicle is stopped, then the steering torque is improved, but the spatial limitation and device complexity worsen
Solution Approach 1:
The patent divides the steering system into two independent motor units: a steering motor for generating steering torque and a driving motor for generating driving force. This segmentation allows each motor to be optimized for its specific function, enabling the steering motor to maintain smaller size while the driving motor compensates for torque requirements during stopped steering operations
Solution Approach 2:
The driving motor is designed to serve dual purposes: generating driving force for vehicle movement and providing additional steering torque when the vehicle is stopped. This multi-functionality eliminates the need for the steering motor to independently handle all torque requirements, reducing its size and spatial requirements
2Adaptability or versatility
If both driving motor and steering motor are provided in four-wheel independent steering system, then the steering capability is improved, but the spatial limitation worsens
Solution Approach 1:
The patent merges the functions of driving and steering into a coordinated control system where both motors work together. The driving motor and steering motor are integrated through a control unit that coordinates their operations, allowing the system to achieve four-wheel independent steering capability while optimizing the spatial arrangement and reducing overall system complexity
3Force
If the capacity of steering motor is increased to satisfy steering torque during full turn in stop state, then the steering torque is improved, but the weight and volume increase
Solution Approach 1:
The patent segments the torque generation function between two motors, allowing the steering motor to be sized for normal steering operations while the driving motor provides additional torque during stopped conditions. This segmentation prevents the steering motor from being oversized for peak stopped steering requirements
Solution Approach 2:
The driving motor serves itself by providing both driving force and steering torque assistance. When the vehicle is stopped, the driving motor automatically contributes to steering torque generation, eliminating the need for the steering motor to independently handle all torque requirements and thus reducing its weight
Data Source
AI summary
An apparatus of assisting steering of a vehicle, may include a turning direction recognizer that recognizes a turning direction of a tire, by use of a steering angle controlled through manipulation of a handle; and a tire driving controller that determines a tire, to which a first driving force for generating a steering assisting torque that assists turning of the tire to the recognized turning direction is applied, and a tire, to which a second driving force for offsetting the first driving force to maintain a forward/rearward force of the vehicle at 0 is applied, and controls driving motors provided in the tires, respectively, to generate the first driving force and the second driving force, whereby the tire may be turned with a steering torque of a limit steering torque or more which may be generated by the steering motor, and a control method thereof.