Ship Speed Control with Adaptive Throttle Gain for Ride Stability
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Solution Overview
Problem
Conventional ship speed control methods fail to consider ride quality and passenger safety, primarily focusing on eliminating the difference between actual and target ship speeds without addressing external disturbances that cause instability.
Innovation Solution
A ship speed control apparatus and method that calculates ship speed deviation, adjusts input gains for throttle control based on thresholds, and incorporates a proportional integral (PI) control to stabilize ship speed, ensuring ride quality and safety by dynamically adjusting gains and prohibiting excessive adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ship speed control focuses only on eliminating the difference between actual and target ship speed, then the speed control accuracy is improved, but the ride quality and passenger safety deteriorate due to external disturbances
Solution Approach 1:
The patent applies dynamics by making the input gain adjustable based on ship speed deviation magnitude. The system dynamically switches between a first gain value (for large deviations) and a second gain value (for small deviations), allowing the control characteristics to adapt to different operational conditions. This resolves the contradiction by improving speed accuracy when needed while maintaining ride quality through gentler control when close to target speed.
Solution Approach 2:
The patent changes the control parameter (input gain) based on the ship speed deviation. When deviation is large, a first gain value is used for aggressive correction; when deviation is small, a second gain value (smaller than first) is used for fine-tuning. This parameter adaptation allows the system to achieve both fast convergence and smooth operation, resolving the contradiction between speed accuracy and ride quality.
2Productivity
If aggressive control is applied to quickly eliminate speed deviation, then the productivity is improved, but the ride quality deteriorates due to excessive control actions
Solution Approach 1:
The system dynamically adjusts the input gain based on the magnitude of speed deviation. For large deviations, a higher first gain value enables rapid response and efficient speed adjustment. For small deviations, a lower second gain value provides gentle control that maintains ride quality. This dynamic adaptation resolves the contradiction between productivity and ride quality.
Solution Approach 2:
The patent applies partial control action by using different gain values for different deviation ranges. Instead of always applying maximum control effort, the system uses a first gain value for large deviations (when productivity is prioritized) and a second, smaller gain value for small deviations (when ride quality is prioritized). This selective application of control strength resolves the contradiction.
Data Source
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AI summary
A ship speed control apparatus (10) includes: a ship speed deviation calculation module (212) which calculates a ship speed deviation based on the difference between an actual ship speed (V) and a ship speed target value (Vt); and an input gain adjustment module (214) which adjusts a gain input to a throttle control function to a first gain value when the ship speed deviation is not less than a first threshold value, and adjusts the input gain to a second gain value which is larger than the first gain value and smaller than the initial gain value when the ship speed deviation is not less than the first threshold value and not less than the second threshold value.