Jib Crane State Control for Pendulum Oscillation Damping
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Solution Overview
Problem
Conventional methods for controlling jib cranes are inadequate in effectively damping pendulum oscillations, particularly in complex crane structures, due to insufficient predictability of load position and dynamic influences like wind pressure, leading to chaotic oscillations and increased pendulum oscillation risks.
Innovation Solution
A state control method that uses a state vector to detect and adjust the movement of a suspended load's position and speed, determining manipulated variables to control the crane's movement based on actual load position and speed, rather than relying solely on hoist rope angle, thereby reducing pendulum oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional control methods based on hoist rope angle are used, then the control system is simple, but the measurement precision of load position is insufficient leading to inadequate pendulum damping
Solution Approach 1:
The control system is segmented into multiple independent sensor units (hoist rope angle sensor, load position sensor, speed sensor) that each detect specific parameters. This segmentation allows high measurement precision for load position and speed while keeping each individual sensor simple and manageable
Solution Approach 2:
The control unit serves multiple functions: it processes data from various sensors, calculates manipulated variables, controls drive devices, and adjusts crane operations. This multi-functionality achieves high measurement and control precision without proportionally increasing system complexity
2Reliability
If predictive control is used to suppress sway, then pendulum oscillation is reduced, but the system becomes more complex and harder to model accurately
Solution Approach 1:
The control system continuously measures actual load position and speed, compares them with target values, and adjusts manipulated variables based on the difference. This feedback mechanism reliably suppresses pendulum oscillations while using simple, direct control logic rather than complex predictive algorithms
Solution Approach 2:
The system calculates manipulated variables in advance based on current state variables and target values, preparing control commands before actual pendulum oscillations occur. This preliminary action enables effective oscillation suppression through proactive control rather than reactive correction
3Productivity
If manual control is used, then the operation is simple, but the productivity is reduced due to longer transport cycles
Solution Approach 1:
The control system automatically calculates manipulated variables and adjusts crane operations based on measured state variables and target values. This self-service capability increases productivity by eliminating manual intervention while the system remains intuitive and easy to operate through automated decision-making
4Manufacturing precision
If conventional sway control devices are used, then the device is simple, but the manufacturing precision of load positioning is insufficient
Solution Approach 1:
The system replaces simple mechanical control devices with an automated control system that uses sensors, calculation units, and automated actuators. This substitution achieves high load positioning precision through electronic control and feedback mechanisms rather than mechanical precision
Data Source
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AI summary
The invention relates to a method for operating a jib slewing crane (2) using a state control system, wherein the state control system controls the movement of a suspended load (L) at least in one direction of movement and is based on a state vector, comprising the following steps: - Acquiring state variables of the state vector, which includes information on a position (x, θ) and a velocity (x`, θ') of a movable suspension point (AUP) to which a load system comprising a hoist rope (HSL), a load-handling device (UF) arranged at a lower end of the hoist rope (HSL), and a load (L) suspended below the load-handling device (UF) is attached, and includes information on a load position (ϕx, ϕy) and a load velocity (ϕ'x, ϕ'y) of a center of mass of the load system with respect to the suspension point (AUP), - Determining at least one manipulated variable (u∗LK, u∗DW,u∗HW) for the movement of the suspension point (AUP) in at least one direction of movement based on state control; - operation of the jib slewing crane (2) depending on the at least one manipulated variable (u∗LK, u∗DW, u∗HW).,