Crane Positioning Using Signal Strength RSSI
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Solution Overview
Problem
Existing methods for guiding cranes along fixed routes, such as those using signal propagation time methods, face challenges in accuracy and complexity, especially in complex spatial situations, and require precise clocks and adjustments.
Innovation Solution
A method utilizing signal strength, specifically Received Signal Strength Indication (RSSI), to determine the relative distance between the crane and the operator, allowing the crane to be moved automatically or semi-automatically to minimize distance, using modern transceivers and existing communication systems, with filtering to stabilize signal fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal propagation time method is used to determine distance, then positioning can be achieved, but measurement precision deteriorates due to multiple reflections and signal superposition in complex spatial situations
Solution Approach 1:
The patent changes the measurement parameter from signal propagation time to signal strength (RSSI). By using signal strength instead of time of flight, the system avoids the problems of multiple reflections and signal superposition that plague time-based methods. The signal strength naturally attenuates with distance according to the inverse square law, providing a more reliable distance indicator in complex spatial environments with reflections.
2Measurement precision
If two transmitters (infrared and ultrasonic) are used simultaneously to determine distance, then positioning can be achieved, but device complexity increases
Solution Approach 1:
The patent extracts and uses only the signal strength information from a single electromagnetic wave transmitter, discarding the need for multiple transmitter types. By taking out the essential measurement capability (distance determination) and achieving it through a simpler means (signal strength of one transmitter), the system reduces device complexity while maintaining positioning functionality.
Solution Approach 2:
The patent replaces the mechanical complexity of multiple physical transmitters (infrared and ultrasonic) with a simpler electromagnetic field-based solution. By substituting the need for multiple mechanical transmitter components with a single electromagnetic transmitter whose signal strength can be measured, the system achieves the same positioning goal with reduced complexity.
3Measurement precision
If time of flight method is used for positioning, then distance can be calculated, but ease of manufacture deteriorates due to requirement for precise clocks and their adjustment
Solution Approach 1:
The patent substitutes the complex time-synchronization mechanism (precise clocks) with a simpler signal strength measurement approach. Instead of requiring synchronized timing equipment and complex clock adjustment procedures, the system uses the naturally occurring signal strength attenuation with distance, which can be measured by any standard receiver without requiring precise time synchronization infrastructure.
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
This approach simplifies the implementation, provides reliable and accurate positioning, and reduces operational time by leveraging existing wireless communication technology, ensuring efficient and safe crane operation.
Implementation Method 1
transmitting electromagnetic waves between a wireless crane-controlled manual control device assigned to the crane and the crane and receiving the electromagnetic waves by means of a receiver unit
Data Source
Figure 1
Figure 2
AI summary
The method involves emitting electromagnetic waves between a wireless manual control unit (5) for the crane control and a crane (1). The manual control unit is assigned to the crane. The electromagnetic waves are received by a receiving unit (8). The signal strength of the transmitted signals (S) is determined, where the signals are received from the receiving unit.