Crane Load Oscillation Damping via Trajectory Planning
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Solution Overview
Problem
Existing crane and excavator systems face challenges in damping load oscillations during transfer, particularly when moving in multiple degrees of freedom, as they require costly rope angle sensors and do not adequately account for friction effects, leading to inefficiencies in load positioning and transfer speed.
Innovation Solution
A computer-controlled regulator with a fully automatic trajectory planner, centripetal force compensation, and axis controllers for the slewing and luffing mechanisms, which allows for precise load positioning and minimization of oscillations without the need for rope angle sensors, by generating modified hand lever signals and using state controllers to manage slewing and luffing dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rope angle sensors are used for load oscillation damping, then oscillation suppression precision is improved, but system cost increases
Solution Approach 1:
The patent extracts the rope angle sensor from the system and replaces it with alternative measurement approaches using existing sensors (accelerometers, gyroscopes, position sensors) to detect load oscillations through mathematical models and signal processing, thereby eliminating the costly specialized sensor while maintaining oscillation detection capability
Solution Approach 2:
The patent replaces the mechanical/physical rope angle sensor with a computational approach using mathematical models that calculate rope angle and oscillation parameters from data obtained by standard sensors and system state measurements, substituting physical measurement with computational derivation
2Device complexity
If friction effects are not considered in control calculations, then computational simplicity is improved, but control accuracy deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the actual system response including friction effects is continuously measured and compared with model predictions, and the control parameters are adjusted based on the deviation to compensate for friction without requiring explicit friction modeling in the primary control calculations
Solution Approach 2:
The patent changes the control parameters to include friction compensation terms or adaptive parameters that automatically adjust to account for friction effects, allowing the system to maintain accuracy while keeping the base control model relatively simple
3Productivity
If transfer speed is increased to improve productivity, then load oscillation damping becomes more difficult
Solution Approach 1:
The patent applies preliminary action by predicting future load positions and oscillation states based on current system state and trajectory plans, then proactively adjusting control parameters in advance to prevent oscillation buildup before it occurs, enabling faster transfers while maintaining stability
Solution Approach 2:
The patent implements dynamic control parameters that adapt in real-time based on the current transfer phase, load position, and oscillation state, allowing the system to optimize between speed and stability at different moments during the transfer operation rather than using fixed conservative parameters
4Ease of operation
If automatic trajectory planning is implemented, then operator demand is reduced, but system complexity increases
Solution Approach 1:
The patent implements multi-functionality by designing the trajectory planner to handle multiple types of transfers, oscillation damping scenarios, and operational modes within a single integrated system, reducing the need for separate specialized systems while providing comprehensive automatic control
Solution Approach 2:
The patent applies self-service by enabling the system to automatically plan and execute its own trajectory and oscillation control without external operator intervention, with the control system monitoring and adjusting itself based on real-time feedback from sensors and system state measurements
Data Source
AI summary
The invention relates to a method for the transfer of a load hanging at a load rope of a crane or excavator comprising a slewing gear, a luffing mechanism and a hoisting gear comprising a computer-controlled regulator for the damping of the load oscillation which has a trajectory planner, a disturbance observer and a state regulator with a pre-control, wherein the working space is first fixed by selection of two points, with one of the two points being fixed as the destination point by direction presetting by means of the hand lever and with the nominal speeds for the slewing gear and the luffing mechanism being preset by the hand lever signals.