Bridge Crane Anti-Swing Control for Variable Rope Lengths
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Solution Overview
Problem
Current bridge crane control systems face challenges in anti-swing positioning control, particularly with variable rope lengths, due to complexity and the chattering phenomenon associated with sliding mode control, which is not effectively addressed by existing methods.
Innovation Solution
A bridge crane anti-swing method based on first-order dynamic sliding mode variable structure (SMVS) that monitors system parameters, establishes a two-dimensional model, constructs dynamic sliding mode surfaces, and uses an exponential approach law control method to derive traction forces, thereby reducing chattering and achieving smooth control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sliding mode control is used for bridge crane anti-swing control, then positioning control performance is improved, but chattering phenomenon occurs and control complexity increases
Solution Approach 1:
The patent employs dynamic sliding mode surfaces that adapt to variable rope lengths, making the control system dynamic rather than static. The sliding mode surfaces are continuously adjusted based on real-time rope length changes, which reduces chattering while maintaining positioning precision. This is achieved by making the control parameters time-varying and state-dependent.
Solution Approach 2:
The patent changes the control parameters dynamically based on rope length variations. By adjusting the sliding mode surface parameters according to actual rope length, the system adapts to changing conditions without generating chattering. This parameter adaptation allows the system to maintain precision while avoiding the harmful chattering effect.
2Adaptability or versatility
If hierarchical sliding mode and time-varying sliding mode control methods are used for variable rope length, then anti-swing positioning control is achieved, but design complexity increases and chattering is not effectively addressed
Solution Approach 1:
The patent uses dynamic sliding mode surfaces that automatically adapt to variable rope lengths through real-time parameter adjustment. This dynamic approach achieves adaptability without the complex hierarchical structure, simplifying the control design while maintaining effectiveness for variable rope length scenarios.
Solution Approach 2:
The control parameters are dynamically changed based on rope length measurements, allowing the system to adapt to variable rope lengths. This parameter adaptation strategy achieves versatility without requiring complex hierarchical control structures, reducing design complexity while maintaining adaptability.
3Reliability
If conventional sliding mode control is used, then robust control performance is achieved, but chattering phenomenon cannot be effectively suppressed
Solution Approach 1:
The patent transitions from static to dynamic sliding mode control, where the control surfaces adapt in real-time to system conditions. This dynamic approach maintains robustness by continuously adjusting to disturbances while suppressing chattering through smooth parameter transitions and adaptive boundary layer management.
Solution Approach 2:
The control parameters are dynamically adjusted based on system state and rope length, allowing the system to maintain robust performance while reducing chattering. The parameter changes enable the controller to adapt its aggressiveness, maintaining robustness when needed while suppressing chattering during normal operation.
Data Source
AI summary
A bridge crane anti-swing method based on first-order dynamic sliding mode variable structure includes steps of: constructing a two-dimensional bridge crane system model and a crane system control model, respectively; performing differentiation on two sliding mode surfaces containing swing angle dynamic change and rope length dynamic change to obtain a crane position dynamic sliding surface s1 and a rope length dynamic sliding mode surface s2, respectively; combining a displacement x, a length l and a swing angle θ in the two-dimensional bridge crane system model with the crane position dynamic sliding surface s1 and rope length dynamic sliding mod surface s2 in the crane system control model to obtain a relationship among a horizontal traction force f1, an along-rope traction force f2, the displacement x, the length l and the swing angle θ.