Dynamic Steering Angle Limiting for Mobility Scooter Stability

Solution Overview

Problem

Existing passenger conveyance devices, such as mobility scooters, face instability issues when turning at high speeds due to uncontrolled steering angles, leading to potential tipping over, especially in emergency situations, as existing solutions either fail to react quickly enough or reduce maneuverability.

Innovation Solution

Implementing a system that limits the steering angle based on speed, where exceeding a predefined angle results in speed reduction, allowing a maximum steering angle in emergencies while maintaining stability and comfort by adjusting the steering force and angle restrictions dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steering angle is allowed to be large for maximum maneuverability, then the device can turn sharply even at high speeds, but the device becomes unstable and may tip over

Engineering Contradiction:

ImprovemaneuverabilityVSAvoidstability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The steering angle limit is made dynamic rather than fixed. The control device adjusts the maximum allowable steering angle based on the current speed of the drive wheel - allowing larger angles at low speeds for maneuverability while restricting angles at high speeds for stability. This dynamic adaptation resolves the contradiction between maneuverability and stability across different operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the steering angle parameter based on speed conditions. When the drive wheel speed exceeds a threshold, the control device reduces the maximum steering angle from a first larger angle to a second smaller angle. This parameter change ensures stability at high speeds while preserving maneuverability at low speeds.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the steering angle is limited to prevent instability, then stability is maintained, but the device cannot respond quickly enough in emergency situations

Engineering Contradiction:

ImprovestabilityVSAvoidresponse speed

Core Design Contradiction:

Stability of the object's compositionVSSpeed

Solution Approach 1:

The steering angle limit is made dynamic rather than fixed. The control device adjusts the maximum allowable steering angle based on the current speed of the drive wheel - allowing larger angles at low speeds for maneuverability while restricting angles at high speeds for stability. This dynamic adaptation resolves the contradiction between maneuverability and stability across different operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the steering angle parameter based on speed conditions. When the drive wheel speed exceeds a threshold, the control device reduces the maximum steering angle from a first larger angle to a second smaller angle. This parameter change ensures stability at high speeds while preserving maneuverability at low speeds.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the steering angle is reduced at high speeds, then stability is improved, but maneuverability is reduced

Engineering Contradiction:

ImprovestabilityVSAvoidmaneuverability

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The steering angle limit is made dynamic rather than fixed. The control device adjusts the maximum allowable steering angle based on the current speed of the drive wheel - allowing larger angles at low speeds for maneuverability while restricting angles at high speeds for stability. This dynamic adaptation resolves the contradiction between maneuverability and stability across different operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the steering angle parameter based on speed conditions. When the drive wheel speed exceeds a threshold, the control device reduces the maximum steering angle from a first larger angle to a second smaller angle. This parameter change ensures stability at high speeds while preserving maneuverability at low speeds.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2530002B1Passenger conveyance device with automatic steering angle limitation and speed reduction

Publication Date: 2015.01.14 SUNRISE MEDICAL LTD

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AI summary

The invention relates to a passenger conveyance device comprising at least one first wheel and at least one second wheel, wherein the first wheel acts as a drive wheel and the second wheel acts as a steerable wheel, a steering angle of the second wheel measured relative to a steering position of the second wheel corresponding to a forward or rearward traveling direction of the passenger conveyance device is limited to a first steering angle based on a first value representative for a speed of the passenger conveyance device, especially of the first wheel, wherein further in case the steering angle exceeds a predefined second steering angle the speed of the passenger conveyance device is limited to a second value, as well as a method for controlling a steering angle of a passenger conveyance.