Landing Gear WOW Sensor for Immediate Ground Contact Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional landing gear systems for VTOL aircrafts lack precise and immediate feedback on landing or taking off, relying on shock absorber compression which is delayed and unreliable.
Innovation Solution
A weight on wheels (WOW) system with a sensor assembly and landing disc assembly that activates a switch upon minimal ground contact force, independent of main landing gear compression, providing immediate and reliable landing or taking-off feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional landing gear systems rely on shock absorber compression to detect landing or take-off, then the system structure is simple, but the detection precision and response speed are insufficient
Solution Approach 1:
The landing gear system is segmented into independent functional modules: the shock absorber maintains its original shock absorption function, while a separate landing disc assembly with switch activation element detects ground contact. This segmentation allows the detection function to be improved without compromising the shock absorption capability, and the switch can be positioned optimally for detection precision without affecting the overall gear structure.
Solution Approach 2:
A switch activation element is introduced as an intermediary between the landing disc and the switch. This intermediary translates the mechanical ground contact force into a reliable electrical signal by moving towards the switch when the landing disc touches the ground, providing precise detection without requiring direct integration of complex sensing mechanisms into the shock absorber itself.
2Reliability
If the switch activation element requires high force to activate, then the system is more robust, but cable entanglement risk increases and response time decreases
Solution Approach 1:
The activation force parameter of the switch is optimized to a low threshold that is sufficient for reliable detection of actual ground contact. The spring element's pre-load and stiffness are carefully selected so that the switch activates with minimal force (lower than conventional systems), enabling rapid response during landing or take-off while maintaining reliability through the mechanical advantage of the landing disc lever arm.
Solution Approach 2:
The switch activation element is pre-positioned close to the switch contact point, and the spring element is pre-loaded to provide immediate responsiveness. When ground contact occurs, the activation element is already in optimal position to quickly trigger the switch, minimizing response time. The system is prepared in advance to detect ground contact instantly without requiring significant force buildup.
3Speed
If the switch is positioned closer to the landing disc, then the detection is more immediate, but the risk of cable entanglement during rotation increases
Solution Approach 1:
The switch and its activation mechanism are extracted from the rotating landing disc assembly and positioned on the stationary shock absorber body. The landing disc can rotate freely during shock absorber operation without dragging cables, while the switch remains in a fixed position where it can be reliably activated by the landing disc's radial movement during ground contact, eliminating cable entanglement risks while maintaining detection speed.
Solution Approach 2:
A dedicated switch activation element serves as an intermediary that transfers the ground contact detection function from the rotating landing disc to the stationary switch. This activation element moves radially towards the switch when the landing disc touches the ground, providing immediate detection without requiring the switch itself to be positioned on the rotating disc, thus avoiding cable entanglement while maintaining fast response.
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 WOW system offers precise and rapid detection of ground contact, requiring lower activation forces and reducing cable entanglement risks, ensuring safe and reliable operation with redundancy, and serving as crucial input for autopilot systems during critical phases.
Implementation Method 1
a switch activation element (1665) arranged at the inner connection element (1662) and configured to trigger the switches (140) when passing close to the switches (140) in an operational state
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A weight on wheels, WOW, system (12) for a landing gear system (1) is disclosed. The WOW system (12) comprising: a sensor assembly (13) comprising a switch (140) and configured to be mounted to a shock absorber (11); and a landing disc assembly (16) connected to the sensor assembly (13), the landing disc assembly (16) configured to contact a ground surface and to be mounted to the shock absorber (11). The switch (140) is configured to indicate a landing or a taking-off of an aerial vehicle from the ground surface. Also disclosed is a landing gear (1) for an aerial vehicle and a method for operating a take-off- and-landing gear of an aerial vehicle.