Fan Rotor Collision Prevention Using Trajectory-Based Speed Control
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Solution Overview
Problem
Fans with protective grilles suffer from reduced efficiency due to airflow throttling and noise caused by turbulence, and are not accessible when intended to be non-interactive, such as in cars or PCs, while existing solutions like control units with distance sensors are inadequate for preventing collisions with rotating parts.
Innovation Solution
A fan design without an axial protective grille, equipped with a sensor device to detect approaching objects and a control device that adjusts the rotor's angular position or speed to prevent collisions, using braking, acceleration, or pyrotechnically inflatable cushions to ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective grille is installed on the fan, then safety against collision with rotor is improved, but airflow efficiency deteriorates due to throttling
Solution Approach 1:
The protective grille is completely removed from the fan structure. Instead of using a physical barrier, the invention employs an active detection and response system with sensors and control units that monitor for approaching objects and adjust rotor operation to prevent collision, thereby maintaining safety without the airflow obstruction caused by a grille
Solution Approach 2:
The passive mechanical protective grille is replaced with an active electronic control system comprising sensors (optical, acoustic, or other detection devices), a control unit for processing sensor data, and actuators for adjusting rotor speed or position. This substitution eliminates the mechanical obstruction while providing dynamic collision prevention
2Reliability
If a protective grille is installed on the fan, then safety against collision with rotor is improved, but noise level increases due to turbulence
Solution Approach 1:
The protective grille is completely removed from the fan structure. Instead of using a physical barrier, the invention employs an active detection and response system with sensors and control units that monitor for approaching objects and adjust rotor operation to prevent collision, thereby maintaining safety without the airflow obstruction caused by a grille
Solution Approach 2:
The passive mechanical protective grille is replaced with an active electronic control system comprising sensors (optical, acoustic, or other detection devices), a control unit for processing sensor data, and actuators for adjusting rotor speed or position. This substitution eliminates the mechanical obstruction while providing dynamic collision prevention
3Reliability
If the rotor is braked to prevent collision, then safety is improved, but response time may be insufficient for very fast objects
Solution Approach 1:
The control system continuously monitors for approaching objects using sensors and calculates their trajectories in advance. When a potential collision is detected, the system initiates rotor braking or acceleration before the object reaches the rotor, maximizing the available response time and ensuring safety even for fast-moving objects
Solution Approach 2:
The system dynamically adjusts rotor speed based on real-time sensor data and calculated trajectories. Instead of a fixed response mode, the control unit can accelerate the rotor to move blades away from the object's path or brake it to stop potential collisions, selecting the optimal action based on the object's speed, size, and trajectory
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 solution effectively prevents collisions with rotor blades while maintaining fan efficiency and accessibility, providing quick response times to potential hazards and ensuring safety without overloading the rotor blades.
Implementation Method 1
The sensor device can be designed to detect an object approaching the rotor blade with sufficient accuracy in terms of its current position, speed and acceleration and to convert optical signals into machine-readable analog or digital signals
Implementation Method 2
a decelerating, pyrotechnically inflatable collecting cushion, which is ignited before a rotor blade is about to collide with the object and which stops the rotor blade
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a fan 1, comprising a rotor 3 which is rotatably mounted about an axis of rotation 2 and on which blade-like rotor blades 5 are arranged, further comprising: • a sensor device 7 for detecting a possibly present object 8 which approaches a rotor blade 5, • a control device 9 which is connected to the sensor device 7 and the fan 1 for signal transmission, • wherein the control device 9 is configured to extrapolate a trajectory 11 of the object 8 from a position x and a velocity v of the object 8, • and wherein the control device 9 is further configured to influence an angular position or rotational velocity n of the rotor 3 in such a way that the object 8 can continue to move along its trajectory 11 without a collision with one of the rotor blades 5.