Marine Trim Actuator Control via Variable Activation Time
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Solution Overview
Problem
Existing auto-trim systems for marine vessels face inaccuracies in trimming positions due to discrete actuator control, leading to overshooting or undershooting of target positions, and issues with inertia and hydraulic line expansion, which affect the precise control of trim angles.
Innovation Solution
A method and system that utilize a controller to determine the activation time of a trim actuator based on the magnitude of trim position error and acceleration rate, sending control signals to adjust the trim position and discontinuing them once the activation time expires, employing open-loop control for fine corrections and closed-loop feedback for coarse corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete actuator control is used for auto-trim systems, then the system structure is simple, but trimming position accuracy deteriorates due to overshooting or undershooting of target positions
Solution Approach 1:
The patent applies dynamics by making the actuator activation time variable rather than fixed. The controller adjusts the activation time based on real-time feedback from position sensors and feedback from acceleration rate sensors, allowing the system to adapt to changing conditions and achieve precise trim positioning without overshooting or undershooting target positions.
Solution Approach 2:
The patent implements feedback control by using position sensors to detect actual trim position and acceleration rate sensors to measure vessel acceleration. The controller receives this feedback information and uses it to dynamically adjust actuator activation time, creating a closed-loop control system that continuously corrects positioning errors and achieves high measurement precision.
2Measurement precision
If activation time is extended to account for hydraulic line expansion and actuator inertia, then positioning accuracy improves, but response time to reach target position increases
Solution Approach 1:
The system dynamically adjusts activation time based on actual operating conditions rather than using a fixed extended time. By incorporating feedback from position and acceleration sensors, the controller optimizes activation time in real-time, extending it only when necessary to compensate for hydraulic line expansion and actuator inertia, thereby minimizing response time while maintaining positioning accuracy.
Solution Approach 2:
The controller performs preliminary calculation of required activation time based on expected hydraulic line expansion and actuator inertia before actuator activation. This preliminary action allows the system to pre-compensate for known delays, reducing the overall response time while ensuring the actuator reaches the target position accurately.
3Measurement precision
If feedback control is used for coarse corrections, then overall control accuracy improves, but system complexity and response time for fine adjustments increases
Solution Approach 1:
The patent segments the control process into two distinct phases: coarse corrections using feedback control with position and acceleration feedback, and fine adjustments using open-loop control with predetermined activation times. This segmentation allows each control mode to be optimized independently, maintaining overall control accuracy while simplifying the control algorithm for fine adjustments.
Solution Approach 2:
The system applies partial feedback control by using feedback mechanisms only for coarse corrections when position errors are large, and switches to simpler open-loop control for fine adjustments when approaching the target position. This partial application of feedback control maintains overall accuracy while reducing system complexity and response time for the final positioning phase.
Data Source
AI summary
A method for controlling a trim system on a marine vessel includes receiving an actual trim position of a trimmable marine device at a controller and determining a magnitude of a trim position error by comparing the actual trim position to a target trim position with the controller. The method also includes determining a magnitude of an acceleration rate of the marine vessel. The controller determines the activation time of a trim actuator coupled to and rotating the marine device with respect to the marine vessel based on the magnitude of the trim position error and the magnitude of the acceleration rate. The controller then sends a control signal to activate the trim actuator to rotate the marine device toward the target trim position. The method includes discontinuing the control signal once the activation time expires to deactivate the trim actuator. A corresponding system is also disclosed.