Crane Control System with Dynamic Heave Compensation Allocation
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Solution Overview
Problem
Existing crane control systems with active heave compensation are not sufficiently flexible and can fail, leading to inadequate performance in compensating for heave movements, which affects the stability and precision of load handling, especially in rough sea conditions.
Innovation Solution
A crane control system that allows for the division of kinematically limited variables such as power, speed, and acceleration between heave compensation and operator control, enabling the crane operator to adjust the distribution dynamically using weighting factors, and incorporates separate path planning modules for heave compensation and operator control to ensure continuous operation even if heave compensation fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If active heave compensation is implemented to compensate for cable suspension point movement, then load handling stability is improved, but system complexity increases and reliability decreases due to potential control failures
Solution Approach 1:
The control system is segmented into two independent path planning modules: one for heave compensation and another for operator control. Each module operates separately with its own trajectory generation, allowing the system to maintain stability through heave compensation while preserving operator control capability in case of failures. This modular segmentation isolates potential failure modes and maintains system reliability.
Solution Approach 2:
The system dynamically allocates kinematically limited variables (power, speed, acceleration) between heave compensation and operator control based on real-time conditions. The controller can adaptively adjust the distribution of available control authority, switching between pure heave compensation mode, pure operator control mode, or a hybrid mode where both functions share the kinematic budget, thereby optimizing reliability and stability under varying operational conditions.
2Manufacturing precision
If the entire kinematically limited variable is allocated to heave compensation, then compensation accuracy is improved, but operator control flexibility is reduced
Solution Approach 1:
The system implements dynamic allocation of kinematically limited variables between heave compensation and operator control. The controller can adjust the distribution of power, speed, and acceleration limits based on real-time operational requirements, allowing the operator to prioritize compensation accuracy when needed or maximize control flexibility when conditions permit. This dynamic reconfiguration resolves the contradiction by making the allocation adaptive rather than fixed.
Solution Approach 2:
The system changes the parameters of kinematic limitations (power, speed, acceleration) dynamically between the two control functions. By adjusting these parameters based on current operational conditions and operator needs, the system can shift the balance between compensation accuracy and operator flexibility, allowing both extremes to be achieved when necessary through parameter modification rather than fixed allocation.
3Reliability
If separate path planning modules are used for heave compensation and operator control, then system reliability is improved, but device complexity increases
Solution Approach 1:
The control system is divided into separate path planning modules for heave compensation and operator control, each with independent trajectory generation capabilities. This segmentation improves reliability by isolating failure modes and allowing independent optimization of each function. The modular architecture, while increasing structural complexity, enables more robust and maintainable control logic that can handle diverse operational scenarios.
4Adaptability or versatility
If kinematically limited variables are divided between heave compensation and operator control, then operational flexibility is improved, but control precision may be reduced due to shared resources
Solution Approach 1:
The system dynamically adjusts the allocation of kinematically limited variables based on real-time conditions, allowing precise control when needed and flexible operation when conditions permit. The controller can concentrate resources on precision tasks or distribute them for flexible operation, optimizing the balance between operational flexibility and control precision through adaptive resource allocation rather than fixed division.
Data Source
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AI summary
The present invention relates to a crane control system for a crane which has a hoist for lifting a load suspended from a rope, with an active wave compensation which, by controlling the hoist, at least partially compensates for the movement of the rope suspension point and/or a load setting point due to the sea state, and an operator control which controls the hoist according to the operator's specifications, wherein the distribution of at least one kinematically limited parameter of the hoist between wave compensation and operator control is adjustable.