Using motion capture to track scale models
Qualisys provides solutions for measuring scale models of vessels that helps and aids vessel builders during their development cycle. Even as of today builders of larger marine vessels will not go directly from design/simulations to production of full scale ships in one step only relying on simulations. By testing a scale model of the vessel and how it behaves under various conditions such as different wave patterns/amplitudes, wind types and water currents information about how the real vessel will perform can be predicted.
These type of scale model tests typically takes place in ocean basins (ranging from 15x15m up to 120mx70m in size) or towing tanks (ranging from 5x1m to 500x20m) with a sliding carriage towing the models across the tank.
Get accurate 3D and 6DOF measurements in large volumes
Qualisys measurement system provides accurate positional information about the movement of the scale model throughout the basin/towing tank that can be compared with simulations (and improve the simulations over time) of the predicted behavior of the vessels movement. This will help and aid the vessel designers providing feedback of the structural quality of the ship/vessel design.
In marine applications, measurement volumes are typically very large which makes it difficult to maintain accuracy and volume coverage. Qualisys has developed a special calibration procedure in order to handle this called fixed-camera-calibration enabling coverage of large volumes while maintaining high accuracy.
There is also a need to follow the vessels motion both in air and under water and thus Qualisys has developed specific underwater cameras enabling underwater motion capture.
This technology can also be used for biomechanical measurements (measuring on humans in water as can be seen here).
The benefits of using Qualisys’ optical motion capture for marine applications
Optical motion capture do not require wiring to the vessel during the experiment, the position of the vessel is picked up by the cameras mounted on the side of the basin. Position is very accurately determined and acceleration will be calculated (easier to derive than to integrate in comparison when using inertial measuring sensors).
With optical mocap, it’s easy to get 6DOF data from the system and plug it into various data collection back-ends (for example MATLAB). In addition, our technology can be synchronized with other types of measurement systems. In addition, our rugged hardware is developed for harsh environment conditions (24/7 operation for many years close to water).
Get in touch with us and see if we can help you in your project.
- University of Maryland
- Mike Sullivan – New Foundland