Mobility Scooter Steering Force Control for Stability

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Solution Overview

Problem

Existing mobility scooters face instability issues when turning at high speeds, leading to potential tipping over, as the steering angle is limited by mechanical constraints and existing systems fail to provide sufficient control during emergency maneuvers, reducing maneuverability and comfort.

Innovation Solution

A mobility scooter design that adjusts the force required to alter the steering angle based on speed, using a combination of mechanical and electronic signals to limit the steering angle and reduce speed when necessary, ensuring stability and allowing maximum steering in emergency situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steering angle is allowed to be turned to any angle up to the maximum physically allowed while traveling at high speed, then the maneuverability is improved, but the stability deteriorates and the device may tip over

Engineering Contradiction:
ImprovemaneuverabilityVSAvoidstability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the steering angle limit variable rather than fixed. The control system dynamically adjusts the maximum steering angle based on the current traveling speed of the mobility scooter. At high speeds, the steering angle is automatically limited to a smaller range to maintain stability, while at low speeds, the full steering range is available for maximum maneuverability. This resolves the contradiction by adapting the steering characteristics to the operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of steering angle limit based on speed parameter. The control system monitors the traveling speed and相应地 adjusts the maximum allowable steering angle. This parameter change ensures that at high speeds where stability is critical, the steering angle is restricted, while at low speeds where maneuverability is prioritized, the full steering range is permitted.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the speed is reduced quickly when a sharp turn is detected, then the stability is improved, but the response time is insufficient to prevent tipping over in emergency situations

Engineering Contradiction:
ImprovestabilityVSAvoidresponse time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by proactively limiting the steering angle before the instability occurs. Instead of waiting to detect a sharp turn and then reducing speed, the system continuously monitors speed and preemptively restricts the steering angle to a safe range at high speeds. This prevents the centrifugal forces from building up to dangerous levels in the first place, providing immediate stability protection without requiring delayed speed reduction.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the maximum steering angle is reduced at high speeds, then the stability is improved, but the maneuverability in emergency situations deteriorates

Engineering Contradiction:
ImprovestabilityVSAvoidmaneuverability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent changes the steering angle parameter dynamically based on speed. At high speeds, the maximum steering angle is reduced to maintain stability, while at low speeds, the full steering angle range is restored for maximum maneuverability. This parameter adaptation resolves the contradiction by ensuring that the steering characteristics match the operational requirements at each speed level.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2530005B1Mobility scooter with automatic steering force altering
Publication Date: 2013.11.20 SUNRISE MEDICAL LTD
  • EP2530005B1 patent drawingFigure 1~3c
  • EP2530005B1 patent drawingFigure 3d~3h
  • EP2530005B1 patent drawingFigure 4~5c

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, the second wheel acts as a steerable wheel and a steering angle of the second wheel is measured relative to a steering position of the second wheel corresponding to a forward or a rearward traveling direction of the passenger conveyance device, wherein further based on a first value representative for a speed of the passenger conveyance device, especially of the first wheel, a force necessary for altering the steering angle in at least one predefined region is changed, and a method for controlling the steering of a passenger conveyance device.