Rotary Tower Crane Controller Dynamic Load Management
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Solution Overview
Problem
Existing cranes face limitations in load capacity and stability, particularly during fast movements and high loads, as they rely solely on load and radius monitoring, neglecting dynamic values like movement speed and acceleration, which can lead to instability and safety concerns.
Innovation Solution
Implementing a crane controller with multiple load limits and actuation modes that allow individual actuation of drive devices in extended load capacity ranges, where simultaneous actuation is restricted to reduced speeds and accelerations, and introducing a pause between drive device activations to manage dynamic loads and enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the crane allows simultaneous actuation of multiple drive devices to enable fast crane or load movements, then the productivity and speed of operation are improved, but the dynamic loads increase and the stability and safety of the crane deteriorate
Solution Approach 1:
The crane control system dynamically adjusts operational parameters based on real-time conditions. The monitoring device continuously tracks load, radius, speed, and acceleration, and the control system automatically modifies permissible operations to maintain stability while maximizing productivity when conditions allow
Solution Approach 2:
The system changes operational parameters (speed limits, acceleration limits, simultaneous actuation permissions) based on the current load and radius conditions. When load and radius are low, the system permits faster movements and simultaneous drive actuation. When load or radius increase, the system restricts these parameters to maintain stability
2Reliability
If the crane reduces travel speeds and acceleration to maintain stability under high loads, then the stability and safety are improved, but the productivity and operational efficiency deteriorate
Solution Approach 1:
The system dynamically adjusts speed and acceleration limits based on real-time monitoring of load and radius. Rather than maintaining constant reduced speeds, the system permits maximum speeds when conditions allow and only reduces speeds when necessary to maintain stability
Solution Approach 2:
The monitoring device continuously monitors crane parameters and periodically adjusts operational permissions. The system alternates between permitting normal operations and imposing restrictions based on whether current conditions exceed stability thresholds
3Quantity of substance
If the crane defines two different load limits with reduced speeds and acceleration for extended load capacity, then the load capacity is improved, but the device complexity and control requirements increase
Solution Approach 1:
The monitoring device and control system serve multiple functions: they monitor load and radius, determine current operational mode, enforce appropriate speed and acceleration limits, and manage permissions for simultaneous drive actuation. This multi-functionality reduces the need for separate dedicated systems for each function
Solution Approach 2:
The system uses parameter changes (switching between normal and extended load modes) to manage complexity. Rather than implementing completely separate control systems for different load capacities, the system modifies operational parameters (speed limits, acceleration limits, simultaneous actuation permissions) based on the current mode
4Quantity of substance
If the crane allows individual actuation of drive devices in extended load capacity range to further increase load capacity, then the load capacity is improved, but the ease of operation and operational flexibility deteriorate
Solution Approach 1:
The system permits partial actuation of drive devices based on current conditions. Rather than completely restricting simultaneous actuation in extended load mode, the system evaluates each drive device activation request and permits it if the resulting dynamic loads remain within stability thresholds, providing partial operational flexibility
Data Source
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AI summary
The invention relates to a crane, in particular a rotary tower crane, having drive devices (9-15) for crane and/or load movements in/around multiple movement axes, and having a crane control system (16) for driving the drive devices, wherein the crane control system has a monitoring device (17) for monitoring the crane loading and restricting crane movements when load limits are reached. The monitoring device has at least two load limits (LM1, LM2, LM3), between which the drive devices can only be actuated individually.