Crane Rope Angle Sensor Error Compensation
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Solution Overview
Problem
Existing crane control systems face challenges in accurately measuring rope angle deviations due to errors caused by crane acceleration and deceleration, leading to incorrect control information and potential accidents.
Innovation Solution
A method and apparatus that utilize an angle sensor located at or adjacent to the trolley to measure rope angle deflection, correct for errors caused by speed changes, and input the corrected feedback into a dead zone unit to modify angle signals, ensuring accurate crane control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor is positioned near the rope anchorage to measure rope angle, then the measurement can be obtained, but acceleration or deceleration of the crane causes error to the measured rope angle
Solution Approach 1:
The patent introduces an intermediary computational process that uses accelerometer data to calculate and compensate for pseudo-forces caused by crane acceleration. The correction value is derived from the relationship between acceleration and gravitational force, acting as a mediator between the raw sensor measurement and the corrected rope angle value.
Solution Approach 2:
The system implements feedback by continuously monitoring accelerometer data and using it to dynamically correct the rope angle measurement. The correction value is calculated based on the measured acceleration and fed back to adjust the final rope angle output, creating a closed-loop measurement system that compensates for dynamic errors.
2Measurement precision
If a sensor is connected in a hook to a controller in the crane, then rope angle can be measured, but long wiring is vulnerable to entanglement or wireless transmitter and receiver are required
Solution Approach 1:
The patent merges the angle sensor and accelerometer into a single integrated measurement unit positioned at the rope anchorage. This combination allows both the rope angle and acceleration data to be collected at the same location, eliminating the need for separate wiring harnesses and reducing system complexity.
Solution Approach 2:
The system uses the crane's existing acceleration sensing capabilities (through integrated accelerometers) to automatically compensate for measurement errors, making the system self-correcting without requiring external calibration or additional complex control infrastructure.
3Measurement precision
If a sensor is located near the hook, then rope angle can be measured, but the sensor is vulnerable to external impacts such as accidental collision with the load
Solution Approach 1:
Instead of positioning the sensor near the hook (close to the load), the patent inverts the measurement approach by positioning the angle sensor at the rope anchorage point on the crane structure. This reverses the measurement direction from load-to-crane to crane-to-load, placing the sensor in a safe, protected location while maintaining measurement capability through geometric relationships.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2B
AI summary
To facilitate the use of a crane, an angle feedback information on a rope angle (theta)of the crane is received, the angle feedback information being measured by means of a sensor at or adjacent to a trolley; and the angle feedback information is corrected by compensating an error caused by a speed change, and processed to provide movement instructions or other control information relating to the crane on the basis of real-time corrected angle information.