Crane Actuator Control with Pulse-Removed Input Smoothing
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Solution Overview
Problem
Existing crane control systems experience discontinuous acceleration leading to load swinging due to step function input, which is exacerbated by inaccuracies in mathematical models, affecting positioning accuracy and increasing load swinging.
Innovation Solution
A control system for cranes that includes a signal processing unit to remove pulse-shaped components from input signals, a feedback control unit to adjust actuator operation based on target and actual operating amounts, and a feed-forward control unit to learn actuator characteristics using a weighting factor, stabilizing the learning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optimal control using mathematical model with predictive gain is applied, then positioning accuracy of crane is improved and load swinging is minimized, but when mathematical model has large error, positioning accuracy decreases and load swinging increases
Solution Approach 1:
The patent implements feedback control by using actual operating amount information from the actuator to generate feedback control signals. The feedback control unit compares the target operating amount with the actual operating amount and adjusts the control signals accordingly, ensuring stable operation even when mathematical model errors exist. This feedback mechanism compensates for model inaccuracies and maintains both positioning accuracy and control stability.
Solution Approach 2:
The patent applies feed-forward control using a mathematical model to predict future states and generate control signals in advance. The feed-forward control unit uses the mathematical model of the crane system to calculate predictive control signals that anticipate system behavior, improving positioning accuracy by proactively compensating for delays and dynamics before they affect performance.
2Speed
If step function input signal is used for actuator control, then operation response is immediate, but discontinuous acceleration occurs causing load swinging
Solution Approach 1:
The patent transforms the static step function input into a dynamic signal by generating target operating amount information that varies continuously over time. The signal processing unit converts the abrupt step input into a smoothed target signal that maintains operational responsiveness while eliminating discontinuous acceleration, thereby preventing load swinging through dynamic signal shaping.
Solution Approach 2:
The patent introduces a signal processing unit as an intermediary between the step function input and the actuator. This intermediary component processes the input signal to generate appropriate target operating amount information, acting as a buffer that translates immediate operational commands into smooth control signals that prevent harmful acceleration spikes while maintaining response effectiveness.
Data Source
AI summary
This control system for controlling an actuator of a crane is provided with a signal processing unit for generating a signal related to a target operating amount of the actuator, a feedback control unit for controlling the actuator on the basis of the difference between the signal relating to the target operating amount, and a fed-back signal relating to the operating amount of the actuator, and a feed-forward control unit which controls the actuator on the basis of the signal relating to the target operating amount, in cooperation with the feedback control unit, and learns the characteristics of the actuator by adjusting a weighting factor on the basis of a teaching signal, wherein the signal processing unit converts an input signal into the signal relating to the target operating amount by removing a pulse-shaped component from the input signal.