Crane Path Speed Smoothing for Automated Load Swing Control
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Solution Overview
Problem
Conventional cranes face difficulties in suppressing load swing during automated conveyance along a set path, as existing methods rely on feedback control and struggle to prevent swing without causing it.
Innovation Solution
A crane control method that calculates target conveyance time and speed signals based on point group data, subdivides sections into acceleration, constant-speed, and deceleration phases, and uses a high-order low-pass filter to convert stepwise speed signals into non-stepwise signals, ensuring smooth operation and reducing load swing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control is used to suppress load swing, then load swing can be controlled after it occurs, but it is difficult to prevent load swing from occurring in the first place
Solution Approach 1:
The patent applies preliminary action by calculating and setting the target conveyance time before the load movement begins. The control apparatus pre-determines the optimal conveyance time based on the distance between passing points, and this predetermined time value is used to generate speed commands that prevent load swing from occurring in the first place, rather than reacting after swing occurs
2Productivity
If automated conveyance along a set path is implemented, then productivity is improved, but load swing occurs during conveyance
Solution Approach 1:
The patent employs feedback control by continuously monitoring the actual conveyance progress and comparing it with the target conveyance time. The control apparatus calculates the remaining distance and adjusts the speed command in real-time based on the elapsed time and target conveyance time, ensuring that automated conveyance proceeds without causing load swing
Solution Approach 2:
The patent changes the speed parameter dynamically during conveyance. The control apparatus adjusts the speed command based on the current position, remaining distance, and target conveyance time, creating a variable speed profile that prevents load swing while maintaining automated conveyance efficiency
3Device complexity
If stepwise speed signals are used for control, then control simplicity is maintained, but load swing is caused due to abrupt speed changes
Solution Approach 1:
The patent applies dynamics by transitioning from static stepwise speed signals to dynamic continuous speed signals. The control apparatus generates speed commands that vary continuously over time based on the elapsed time and target conveyance time, creating a smooth speed profile that eliminates abrupt changes and prevents load swing
Data Source
AI summary
There is provided a crane control method whereby shaking of a load is suppressed when automatically transporting the load along a set transport path using a crane; and a crane that is controllable by this control method. The control method includes: calculating a target transport time (Ti) of a load (W), transported by a crane (1), in a section defined by two passing points adjacent in a passing order; calculating, from a distance between the passing points and the target transport time (Ti), a target speed signal of the load (W) in the section; converting a stepped target speed signal, which connects the target speed signal of the section and a target speed signal of another section adjacent to the section, to a non-stepped target speed signal using a target value filter (F); and carrying out control on the basis of the non-stepped target speed signal.