Independent Wheel Steering Geometry for Tight Turns and Stability
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Solution Overview
Problem
Conventional vehicle steering systems face challenges in achieving a small turning radius due to mechanical constraints, such as limited wheel housing space, and existing solutions complicate the structure, increase weight, and are costly, while also limiting the ability to arbitrarily change toe and camber angles.
Innovation Solution
A steering system with a second steering device that includes a mechanical section and a control section, allowing independent steering of wheels through a steering actuator within the tire housing, with a turning angle control module that adjusts wheel angles based on vehicle velocity and steering angle to enhance stability and reduce the minimum turning radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the steering wheel operation amount is increased to reduce the minimum turning radius, then the wheels can be turned to a greater extent, but the wheel housing size must be increased which conflicts with the space required for engine or transmission
Solution Approach 1:
The patent applies dynamics by making the steering geometry changeable during driving. The steering actuator dynamically adjusts the relative position between the knuckle arm and joint part, transitioning between Ackermann geometry (for low-speed stability) and parallel geometry (for high-speed cornering), allowing the wheels to achieve greater turning angles without permanently increasing wheel housing size.
Solution Approach 2:
The patent changes the geometric parameters of the steering system by relatively moving the knuckle arm and joint part. This parameter change allows the steering geometry to be adjusted between different configurations (Ackermann and parallel), enabling larger wheel turning angles while maintaining compact wheel housing dimensions.
2Adaptability or versatility
If the positions of knuckle arm and joint part are changed to alter steering geometries, then the wheel angles can be adjusted, but the structure becomes more complex and requires additional motor actuators that are difficult to provide due to space constraints
Solution Approach 1:
The patent makes the existing steering components multi-functional. The knuckle arm and joint part, which are already part of the steering mechanism, are made adjustable to serve dual purposes: maintaining standard steering function while enabling geometry changes. This avoids adding separate dedicated actuators and reduces overall system complexity.
Solution Approach 2:
The patent merges the geometry-changing function with the existing steering mechanism. The adjustment of knuckle arm and joint part positions is integrated into the conventional steering system architecture, combining structure changing and steering functions into a unified system that reduces overall complexity.
3Adaptability or versatility
If two motors are used to change toe angle and camber angle to arbitrary angles, then the steering geometries can be fully adjusted, but the costs increase and control becomes complicated
Solution Approach 1:
The patent segments the steering control into two parts: the conventional steering wheel controls the primary steering function, while a single steering actuator controls the geometry adjustment. This segmentation allows independent control of steering angle and geometry type, simplifying the overall control architecture compared to using two motors for all adjustments.
4Adaptability or versatility
If a mechanism is added to arbitrarily change toe angle or camber angle, then the wheels can be steered independently, but the mechanism becomes complicated with more components, making it difficult to ensure rigidity and increasing size and weight
Solution Approach 1:
The patent extracts only the essential function needed for independent wheel steering - the ability to change steering geometry - rather than implementing a complete independent steering system for each wheel. By using a single actuator to adjust the knuckle arm and joint part positions, the system achieves independent wheel steering capability with minimal additional components, reducing weight and maintaining rigidity.
Data Source
AI summary
Provided is a steering system capable of enhancing traveling stability when a vehicle drives straight and improving small-turn performance. The steering system includes: a first steering device; a second steering device including a mechanical section configured to individually steer each of left and right wheels by driving a steering actuator and a control section configured to control the steering actuator; and a vehicle information detection section configured to detect a velocity of the vehicle and a steering angle. The control section includes a turning angle control module configured to control the steering actuator pursuant to a predetermined rule in accordance with the velocity of the vehicle and the steering angle so as to control turning angles of the left and right wheels.