Crane Boom and Winch Trajectory Control for Load Sway Inhibition
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Solution Overview
Problem
Existing crane control methods fail to effectively inhibit swaying of loads during transportation due to changes in rope length and load height, leading to inefficiencies in linear transport.
Innovation Solution
A control device that integrates an acquisition unit, horizontal trajectory generation, movement trajectory generation, and movement control unit to manage boom and winch movements based on optimal control theory, considering frequency weighting of sway, to maintain linear transport with inhibited swaying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crane control methods are used that only control boom movements, then the control system is simple, but the load swaying cannot be effectively inhibited when rope length changes
Solution Approach 1:
The patent combines the control of boom movements and winch operations into a unified control system. The control device integrates trajectory generation for both the boom and winch, coordinating their movements to maintain load stability. This merging allows the system to address rope length changes while inhibiting load sway, resolving the contradiction between simple control and effective sway inhibition.
Solution Approach 2:
The control device incorporates feedback mechanisms that monitor load position and sway in real-time. By continuously detecting the load's horizontal position and rope length changes, the system adjusts boom and winch movements dynamically to maintain stability. This feedback loop enables effective sway inhibition without requiring overly complex additional hardware.
2Adaptability or versatility
If the rope length is changed during load transport, then the load can be repositioned vertically, but the load swaying deteriorates at the end point
Solution Approach 1:
The control device generates predetermined trajectories for both boom and winch movements before actual transport begins. These trajectories are calculated to anticipate rope length changes and their impact on load position. By preparing the control paths in advance, the system can smoothly adjust to vertical repositioning while maintaining load stability and preventing sway at the end point.
Solution Approach 2:
The control system dynamically adjusts the coordination between boom and winch based on real-time conditions. When rope length changes occur during transport, the control device modifies the movement trajectories and timing to maintain load stability. This dynamic adaptation allows versatile load repositioning while continuously inhibiting sway through coordinated control adjustments.
3Measurement precision
If additional sensors are added to detect sway angle, then load sway can be precisely measured, but the device complexity and cost increase
Solution Approach 1:
The control device uses the winch's rope length information as an intermediary parameter to infer load position and sway conditions. Instead of directly measuring sway angle with additional sensors, the system calculates load position based on known rope length changes and boom movements. This intermediary approach provides sufficient measurement precision for control purposes without adding complex sensor systems.
Solution Approach 2:
The control device utilizes information already available from the crane's existing sensors and actuators to determine load position and sway conditions. By self-calculating the necessary measurements from rope length and boom position data, the system achieves precise enough measurement without requiring additional sway angle sensors, thereby avoiding increased device complexity and cost.
Data Source
AI summary
This crane control device controls the operation of a boom and a winch and transports a load from a start point to an end point, the control device comprising: an acquisition unit that acquires position information of the start point and position information of the end point; a horizontal trajectory generation unit that, by using an optimal control theory, generates a horizontal trajectory for a distal-end part of the boom as represented by a horizontal-direction component of a straight line linking the start point and the end point; a movement trajectory generation unit that generates a trajectory of movement of the boom for transporting the load so as to follow the horizontal trajectory, and a trajectory of rotational movement of the winch; and a movement control unit that controls the boom and the winch based on the trajectory of movement of the boom and the winch.