Variable Steering Geometry for Straight-Line Stability and Tight Turns
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Solution Overview
Problem
Conventional vehicle steering systems face challenges in achieving a small turning radius due to mechanical constraints and increased complexity, which limits the ability to change steering geometries effectively, affecting traveling stability and small-turn performance.
Innovation Solution
A steering system with a second steering device that includes a mechanical section and a control section, allowing for independent steering of wheels by a steering actuator in the tire housing, with a turning angle control module that adjusts wheel angles based on vehicle velocity and steering angle, enabling changes in steering geometry during driving to optimize turning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
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 turning) and parallel geometry (for high-speed stability), thereby achieving small turning radius without increasing wheel housing size.
Solution Approach 2:
The patent changes the steering geometry parameters dynamically. By adjusting the steering actuator, the system changes the wheel turning angles and steering geometry configuration based on driving conditions, enabling the vehicle to achieve both small turning radius and high-speed stability without requiring larger wheel housing.
2Adaptability or versatility
If the positions of knuckle arm and joint part are relatively changed to change steering geometries, then the wheel angles can be adjusted, but the motor actuator requires extremely large force which is difficult to provide due to space constraints
Solution Approach 1:
The patent segments the steering control into two parts: the main steering wheel operation for general steering, and a supplementary steering actuator for geometry adjustment. This segmentation allows the small actuator to make precise positional adjustments without needing to provide the large forces required for complete steering control.
Solution Approach 2:
The steering actuator performs partial action by only adjusting the relative position of the knuckle arm and joint part to change steering geometry, rather than providing full steering force. This partial adjustment is sufficient to achieve geometry transition without requiring extremely large actuator force.
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 single steering actuator performs multiple functions: it adjusts both the toe angle and camber angle by changing the relative position between the knuckle arm and joint part. This multi-functionality eliminates the need for separate motors for each adjustment, reducing system complexity and cost.
Solution Approach 2:
The patent merges the functions of multiple actuators into a single steering actuator. By combining the adjustment of toe angle and camber angle into one actuator's operation, the system reduces the number of motors and simplifies the control structure while maintaining full steering geometry adjustability.
Data Source
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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 (101) includes: a first steering device (11); a second steering device (150) including a mechanical section (150a) configured to individually steer each of left and right wheels by driving a steering actuator and a control section (150b) configured to control the steering actuator; and a vehicle information detection section (110) configured to detect a velocity of the vehicle and a steering angle. The control section (150b) includes a turning angle control module (37) 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.