Crane Actuator Control with Boom Deflection Compensation
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Solution Overview
Problem
Existing crane control systems struggle to accurately control actuators while considering the influence of boom deflection, leading to decreased positioning accuracy and increased load swinging.
Innovation Solution
A control system that includes a signal processing unit to generate a target operating signal, a feedback control unit to adjust based on fed-back operating signals, a feed-forward control unit to learn actuator characteristics, and a calculation unit to account for boom deflection, thereby correcting intermediate signals to improve actuator control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a crane is controlled according to a predetermined mathematical model to improve positioning accuracy and minimize load swinging, then positioning accuracy may improve, but when the mathematical model has large errors (especially regarding boom deflection), the predictive values become inaccurate, causing decreased positioning accuracy and increased load swinging
Solution Approach 1:
The patent employs feedback control by acquiring actual position information and swing information of the load, then correcting the target position and target swing angle based on these actual values. This closed-loop feedback mechanism compensates for errors in the mathematical model, particularly regarding boom deflection, ensuring that predictive values remain accurate even when the initial model has large errors.
Solution Approach 2:
The patent performs preliminary correction of the target position and target swing angle before executing the control commands. By calculating corrected values that account for boom deflection in advance, the system proactively compensates for model inaccuracies, improving both positioning accuracy and predictive value reliability.
2Measurement precision
If optimal control is performed to achieve positioning and minimize load swinging by feeding back speed and position, then positioning accuracy improves, but discontinuous acceleration occurs at start or stop causing load swinging
Solution Approach 1:
The patent applies preliminary anti-action by correcting the target position and target swing angle in advance to anticipate and counteract the harmful effects of discontinuous acceleration. By pre-calculating corrected values that account for the expected acceleration discontinuities, the system prevents load swinging before it occurs, rather than reacting after the problem arises.
3Speed
If feed-forward control is used to control the actuator on the basis of target operating amount, then response speed improves, but positioning accuracy decreases when the mathematical model has large errors
Solution Approach 1:
The patent combines feed-forward control with feedback correction. The feed-forward control provides fast response by using the target operating amount, while the feedback mechanism continuously monitors actual position and swing information, then corrects the target values to compensate for model errors. This hybrid approach maintains both fast response speed and high positioning accuracy.
Solution Approach 2:
The patent merges feed-forward control and feedback control into a unified control system. The feed-forward component provides rapid initial response, while the feedback component continuously refines the control based on actual system behavior. This combination allows the system to achieve both fast response and high positioning accuracy despite mathematical model errors.
Data Source
AI summary
This control system comprises: a signal processing unit generating a signal related to the target operating amount of an actuator; a feedback control unit that controls the actuator based on the difference between the signal related to the target operating amount and a signal related to the fed-back operating amount; a feed-forward control unit that controls the actuator based on the signal related to the target operating amount in cooperation with the feedback control unit, and learns the characteristics of the actuator by adjusting a weighting factor based on a teacher signal; and a calculation unit that calculates information related to the deflection of the work machine. The signal processing unit corrects intermediate information, which is generated in the process of generating the signal related to the target operating amount, based on the information related to the deflection, and generates the signal related to the target operating amount.