Hoisting Machine Pendulum Length Estimation
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Solution Overview
Problem
Existing load-swing inhibition technologies in hoisting machines face challenges in accurately determining the pendulum length, leading to errors in load-swing models and incomplete suppression of load swing, especially when dealing with various suspended loads.
Innovation Solution
A hoisting machine system that includes a trolley with a hoisting motor, drum, rope, and hook, where a controller determines the transport speed based on the center-of-gravity distance between a predetermined position and the center-of-gravity position of the suspended load, using a combination of rope length and center-of-gravity distance to estimate the pendulum length and inhibit load swing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rope length is used as pendulum length, then device complexity is reduced, but measurement precision deteriorates due to inaccurate load-swing model
Solution Approach 1:
The pendulum length is segmented into two measurable components: rope length (from hoisting drum to hook) and load suspension length (from hook to load center of gravity). This segmentation allows each component to be measured independently using simple sensors, while their sum provides the accurate total pendulum length needed for the load-swing model.
Solution Approach 2:
The system performs preliminary measurement of the load suspension length during the load hoisting process. By detecting the load position during hoisting, the system pre-calculates the pendulum length before transport begins, ensuring accurate load-swing inhibition control is ready when transport starts.
2Measurement precision
If load suspension length is measured during hoisting, then measurement precision improves, but loss of time increases due to additional measurement process
Solution Approach 1:
The load position detection during hoisting serves dual purposes: it performs the necessary pendulum length measurement while simultaneously executing the useful action of hoisting the load. This eliminates idle measurement time by integrating the measurement function into the existing hoisting operation.
Solution Approach 2:
The system performs the pendulum length measurement during the load hoisting process itself, rather than after loading is complete. This preliminary measurement approach ensures the data is collected while the load is being positioned, avoiding additional time loss.
3Speed
If feedforward control is used, then response speed improves, but reliability deteriorates due to inability to handle model errors
Solution Approach 1:
The system performs preliminary measurement of the actual pendulum length during load hoisting, then uses this measured value for feedforward control during transport. This preliminary data collection enables accurate feedforward control by establishing the correct pendulum parameters before the transport phase begins.
Data Source
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Figure 2(a)~2(b)
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AI summary
A hoisting machine includes: a trolley that is transported by self-propulsion means; a hoisting motor mounted on the trolley; a hoisting drum attached to the hoisting motor; a rope attached to the hoisting drum; a hook attached to the rope; and a controller that identifies a transport speed of the trolley. The controller identifies the transport speed of the trolley based on a center-of-gravity distance between a predetermined position and a center-of-gravity position of a suspended load suspended from the hook.