Ship Speed Throttle Limiting for Smooth Low-to-High Acceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ship speed control methods result in sudden speed changes when increasing ship speed settings exceed actual ship speeds, leading to undesirable throttle openings.
Innovation Solution
A ship speed control device with a calculator and throttle command value setter that calculates a throttle calculation value based on the difference between actual and target ship speeds, setting the throttle command value to the throttle upper limit when the actual speed is below a threshold and the calculation value exceeds the limit, preventing sudden throttle increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ship speed setting is increased too high while actual ship speed is low, then the target ship speed increases rapidly, but the actual ship speed changes suddenly causing unstable control
Solution Approach 1:
The patent applies dynamics by making the throttle upper limit variable rather than fixed. The throttle upper limit is dynamically adjusted based on the relationship between actual ship speed and target ship speed. When the difference exceeds a predetermined value, the throttle upper limit is lowered to prevent sudden throttle opening changes, thereby stabilizing ship speed control during transitions from low to high speed settings
Solution Approach 2:
The patent changes the parameter of throttle upper limit based on operating conditions. Instead of using a constant throttle upper limit, the system adjusts this parameter dynamically: when |Vt - V| > ΔV (where Vt is target speed, V is actual speed, and ΔV is a threshold), the throttle upper limit is reduced to prevent abrupt speed changes, thus resolving the contradiction between achieving high target speed and maintaining stability
2Productivity
If the throttle opening is sharply increased to achieve high ship speed setting, then the target ship speed is reached faster, but the actual ship speed changes suddenly causing control instability
Solution Approach 1:
The system dynamically adjusts the throttle upper limit based on the speed difference between actual and target values. When the difference is large (|Vt - V| > ΔV), the throttle upper limit is lowered to prevent sharp throttle opening increases. This dynamic adjustment maintains productivity by still allowing speed increases while ensuring stability by preventing abrupt changes that would cause control instability
Data Source
AI summary
A ship speed control device is provided, which includes a calculator and a throttle command value setter. The calculator calculates a throttle calculation value based on a difference between an actual ship speed and a target ship speed. The throttle command value setter sets, when the actual ship speed is below a first threshold determined based on a given throttle upper limit and the throttle calculation value is at or above the throttle upper limit, a throttle command value to the throttle upper limit.