Variable Steering Damping for Road Feedback Suppression
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Solution Overview
Problem
Vehicle steering systems experience unwanted feedback due to road irregularities or mechanical issues with steerable wheels, leading to loss of control and safety hazards, particularly in autonomous or semi-autonomous vehicles.
Innovation Solution
A dual-damping system with variable damping rates is applied to the steering mechanism, using a first damper for low steering change rates and a second damper for high rates, optionally controlled by a controller to differentiate between surface-induced and intentional steering inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single damping system is used for the steering mechanism, then the structure is simple, but it cannot effectively differentiate between road-induced feedback and intentional steering input, leading to either excessive damping during normal steering or insufficient damping during road irregularities
Solution Approach 1:
The damping system is segmented into two independent dampers: a first damper with a first damping rate for low steering change rates, and a second damper with a second damping rate for high steering change rates. This segmentation allows each damper to specialize in handling specific types of steering inputs, with the first damper handling normal steering operations and the second damper handling road irregularities, thereby improving vehicle control stability without requiring a single complex adaptive system
Solution Approach 2:
The system dynamically switches between different damping rates based on the steering change rate. When the steering change rate exceeds a threshold, the second damper with higher damping rate is activated to suppress road-induced feedback. This dynamic response allows the system to adapt to varying driving conditions automatically, maintaining reliability without complex control algorithms
2Reliability
If high damping rate is applied continuously to suppress feedback from road irregularities, then vehicle control stability is improved, but normal steering operation becomes stiff and unresponsive
Solution Approach 1:
Different damping rates are applied locally based on the steering change rate. The first damper provides a lower damping rate for normal, slow steering operations, ensuring ease of operation and natural steering feel. The second damper provides a higher damping rate only when rapid steering changes occur due to road irregularities. This local differentiation of damping quality allows the system to maintain both stability and maneuverability without compromise
Solution Approach 2:
The damping rate parameter is changed based on the steering change rate. Instead of using a fixed high damping rate, the system switches between a first damping rate (lower) for normal operations and a second damping rate (higher) for rapid steering changes. This parameter change allows the system to suppress feedback only when necessary, maintaining ease of operation during normal steering while improving stability during road irregularities
3Ease of operation
If low damping rate is used to maintain smooth steering operation, then ease of operation is improved, but the system becomes vulnerable to steering feedback from road irregularities
Solution Approach 1:
The damping system is divided into two segments with different damping characteristics. The first damper with lower damping rate handles normal steering operations, ensuring smooth and easy operation. The second damper with higher damping rate handles rapid steering changes caused by road irregularities, providing resistance to feedback. This segmentation allows the system to simultaneously achieve ease of operation and reliability without requiring high damping throughout
Solution Approach 2:
The second damper acts as an intermediary that activates only when needed to suppress road feedback. During normal steering operations, the first damper handles the steering smoothly with low damping. When road irregularities cause rapid steering changes, the second damper intervenes as a mediator to suppress the feedback, protecting the steering system from harmful vibrations while maintaining smooth operation during normal conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively mitigates unwanted steering feedback, maintaining vehicle control and safety by adjusting damping rates based on steering input sources, enhancing stability in various driving conditions.
Implementation Method 1
a first damper having a first damping rate, where the first damper is attached between the steering mechanism and the vehicle; and a second damper having a second damping rate, where the second damper is attached between the steering mechanism and the vehicle
Implementation Method 2
the first damper applies the first damping rate to the steering mechanism in response to a steering change rate of the pair of steerable wheels below a predetermined rate, and where the second damper provides the second damping rate to the steering mechanism in response to the steering change rate above the predetermined rate
Data Source
AI summary
Provided herein is a system and method for damping the steering of a vehicle. Methods of an example include: steering a pair of steerable wheels of the vehicle with a steering mechanism about an axis substantially perpendicular to an axis of rotation of a respective one of the pair of steerable wheels; damping the steering mechanism at a first damping rate in response to a steering change rate of the pair of steerable wheels being below a predetermined rate; and damping the steering mechanism at a second damping rate in response to the steering change rate of the pair of steerable wheels being above the predetermined rate.