Marine Position Sensor with Motorized Tilt for Dynamic Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing position reference sensors for marine vessels face challenges in maintaining the alignment of retro-reflective targets within the field of illumination due to pitch, roll, and heave motions, which can render the system inoperable temporarily.
Innovation Solution
A position reference sensor with a pulsed laser device, a lenticular lens arrangement, and multiple photodiode photodetectors that automatically adjust the optical assembly's inclination based on the level of reflected laser light, ensuring the retro-reflective targets remain centered within the vertically fanned beam, using a servomotor actuator for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the beam divergence is limited to about ±8° above and below a beam centre line, then the laser beam maintains sufficient intensity and precision, but the retro-reflective targets may move out of the field of illumination during significant pitch, roll or heave motion
Solution Approach 1:
The optical assembly is made dynamically adjustable through a motorised tilt mechanism that can change the vertical inclination of the laser beam. This allows the system to adapt its beam direction in real-time to track retro-reflective targets during vessel motion, resolving the contradiction between maintaining precise beam alignment and ensuring continuous target acquisition under dynamic sea conditions
Solution Approach 2:
A gyroscope-based motion sensor provides feedback about the vessel's pitch and roll motion to the control system. This feedback enables the motorised tilt mechanism to automatically adjust the optical assembly's inclination to compensate for vessel motion, ensuring the laser beam continues to illuminate the targets reliably while maintaining measurement precision
2Reliability
If a gyroscope-based motion sensor and motorised tilt mechanism are employed to compensate for pitch and roll motion, then the vertical inclination of the optical assembly can be adjusted, but the system complexity increases
Solution Approach 1:
The system employs automatic control where the gyroscope-based motion sensor continuously monitors vessel motion and the control system automatically adjusts the motorised tilt mechanism to maintain proper beam alignment. This self-service capability eliminates the need for manual intervention while ensuring reliable target tracking, justifying the increased device complexity through automated operation
3Adaptability or versatility
If the motorised tilt mechanism is capable of tilting by ±20° above and below the horizontal plane, then the optical assembly can compensate for pitch and roll motion, but the device complexity and control requirements increase
Solution Approach 1:
The system changes the operational parameters of the optical assembly by enabling variable tilt angles up to ±20° through the motorised mechanism. This parameter adjustment capability allows the system to adapt to different sea states and motion conditions, with the control system managing the complexity through automated parameter adjustment based on gyroscope feedback
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures continuous detection of retro-reflective targets, maintaining their position within the beam's field of illumination and improving the accuracy of position feedback control signals, even in dynamic sea conditions, thereby enhancing the reliability of dynamic positioning systems.
Implementation Method 1
a pulsed laser device for emitting laser light
Implementation Method 2
a lens arrangement comprising a lenticular lens for producing a vertically fanned beam of the laser light
Implementation Method 3
retro-reflective targets fixed to one or more objects
Implementation Method 4
detects laser light reflected by the one or more retro-reflective targets
Implementation Method 5
a plurality of photodiode photodetectors for detecting laser light reflected by a retro-reflective target
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A position reference sensor for a marine vessel comprises an optical assembly including a pulsed laser device for emitting laser light, a lens arrangement comprising a lenticular lens for producing a vertically fanned beam (18) of the laser light emitted by the pulsed laser device and a photodiode (32) comprising a plurality of photodetectors Rx, Ry, Rz for detecting laser light (28) that has been emitted by the pulsed laser device and reflected by a retro-reflective target (22) towards the photodiode (32). The level of reflected laser light incident upon each photodetector is individually detectable and the position reference sensor further comprises an actuator for varying the inclination of the optical assembly. The actuator is automatically controllable based on the level of reflected laser light incident upon each photodetector Rx, Ry, Rz. A position reference sensor for a marine vessel comprises an optical assembly including a pulsed laser device for emitting laser light, a lens arrangement comprising a lenticular lens for producing a vertically fanned beam (18) of the laser light emitted by the pulsed laser device and a photodiode (32) comprising a plurality of photodetectors Rx, Ry, Rz for detecting laser light (28) that has been emitted by the pulsed laser device and reflected by a retro-reflective target (22) towards the photodiode (32). The level of reflected laser light incident upon each photodetector is individually detectable and the position reference sensor further comprises an actuator for varying the inclination of the optical assembly. The actuator is automatically controllable based on the level of reflected laser light incident upon each photodetector Rx, Ry, Rz.