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Student Projects
Contact Information:
Country: Denmark
Year Submitted: 2019
University: Aarhus University, School of Engineering
List of Team Members (with year of graduation):
Silas Andersen - 2020
Mikkel Vendelbo Førrisdahl - 2020
Troels Poulsen - 2022
Jonas Emil Vind - 2022
Niels James Wangsøe - 2022
Faculty Advisers:
Claus Melvad
Main Contact Email Address:
201608890@post.au.dk
Project Information:
Title:
Autonomous Bio Layer Sampler (ABLS)
Description:
ABLS is an autonomous boat made to make biolayer sampling for bio research easier in Greenland. The biolayer is a very fine and fragile layer on top of the water that is needed to be collected in order to understand the impact of the arctic meltwater on the global climate crisis.
Products:
List of NI hardware, software, modules, and toolkits used in the project, as well as other key hardware or software required for the project.
| NI Software |
NI LabVIEW 2018 NI LabVIEW 2018 MathScript RT Module NI LabVIEW 2018 Real-Time Module NI LabVIEW myRIO Toolkit NI VISA NI MultiSIM 14.1 VirtualBench |
| NI Hardware | 2x NI myRIO-1900 |
| Other Hardware |
1x Ismatec™ MS-CA 2/840 Tubing Pump 1x Geared DC Motor, Micro Motors, 510 rpm; 0,2 N-m; E192.12.5 6x SMC Magnetic valve, 2 Ports, NC, 12 V dc, 1/8 inch, VX212AZ1D 1x DC gearmotor 12V E192.12.5; 2,2Nm; 40o/min 1x 12V DC worm geared motor ; 3Nm; 70o/min 1x Xbox 360 controller 1x Servo, HS-485HB 1x LIDAR-Lite v3HP 1x DuelNav GPS150 2x XBee-Pro S2C 2.4GHz RF- transceiver module 2x Parallax Inc 32401 2x WiFi-antenna, 2.4GHz 2x T200 Thruster w/ Basic ESC 4x LiPo 4S, 14.8 V, 25 C, 99.9 kWh 2x Battery decoupler 1x TRACOPOWER 15W isolated DC-DC-converter 1x HQ40D Digitalt multimeter 10x LED (5 blue & 5 red)
Miscellaneous: Aluminium profile POM sheets Acrylic tubes and plates Water pipes Wires capacitors, and fuses |
The Challenge:
Sea surface microlayer (SSM), which is the upper 100 μm of the ocean, covers ~70% of the Earth’s Surface. SSM is a distinct marine compartment that concentrates surface active particles, organisms and compounds that are getting aerosolized by the air bubbles, produced by breaking waves. Even though the global SSM is a quantitatively important source for atmospheric particles and compounds, these have a largely unrecognized impact on atmospheric processes and Earth’s radiation budget.
Despite the huge extent of the ocean’s surface, until now relatively little attention has been paid to the SSM. As it is here the ultimate interface between heat, momentum and mass exchange and the ocean and the atmosphere takes place. Via the SSM, large-scale environmental changes in the ocean such as warming, acidification, deoxygenation, and eutrophication potentially influence cloud formation, precipitation, and the global radiation balance. Due to the deep connectivity between biological, chemical, and physical processes, studies of the SSM may reveal multiple sensitivities to global and regional changes such as large destructive storms. Understanding the processes at the ocean’s surface, in particular involving the SSM as an important and determinant interface, could therefore provide an essential contribution to the reduction of uncertainties regarding ocean-climate feedbacks.
Inerface between SSM and air.
Currently available method for sampling of the SSM is both labor intense and slow. The collection of samples is carried out from a boat, often a small vessel, such as a kajak. The tool to optain SSM sampels, consists of a glass plate which is retracted from the sea manually at a slow speed, the water needs to drip off before the SSM can be scraped into a container. Often this procedure is repeated more than 50 times and so, covering 70% of Earth will be a huge undertaking.
Current method with glass plate
The scope of the project is to analyse and develop a mechanical and autonomous device, to replace
the manual labour currently required.
- How can the time and manual labour of the biologist researching SSM, be freed up?
- How can collection of SSM samples be made safer?*
- How can sample collecting be sped up?
- How can SSM sample collection be made easier for people who are not experts within the field?
*Arctic icebergs are a serious hazard because they can roll without a warning and easily crush a researcher in a kayak that got to close.
The Solution:
The complete solution consists of a physical prototype with a ground station and a complete software program that is upload onto a NI myRIO-1900. Below, the general construction of the prototype is listed, followed by a general overview of the software. For further explanation, the full report of the project is attached.
The Construction
The solution is an autonomous boat that can take 5 water samples of 200 ml each. The boat can be controlled manually with a controller, or the vessel can sail autonomously to predefined GPS coordinates. The solution consists of elements seen in the list below, which collected in a box and mounted on a dinghy solves the task.
• A self-contained box housing electronics.
• A premade dinghy that the box is mounted onto.
• Two myRIO controllers, one for the boat and one for a ground station.
• Communication between the boat and the ground station using WiFi.
• Propulsion and steering in the form of two Blue Robotics brushless thrusters.
• Navigation provided by a compass and a GNSS (GPS 150 DualNav).
• A sample collection system consisting of a rotating acrylic cylinder.
• A sampling handling system using tubes, valves, a peristaltic pump, and sterile medical bags.
• Obstacle avoidance using a LiDAR.
• DC motors for both turning and raising the sampling drum.
• A GoPro to document sample taking.
• Rechargeable LiPo batteries provides power to the system.
View inside the box - here the battery pack and sample bags can be seen.
The sampling system - the buoyancy is calculated and engineered into the design ensuring optimal sampling.
Electrical wiring seen from above without lid - high and low power is separated to reduce electrical interference.
The Software Workflow
From the beginning of the project, a good LabVIEW workflow was a priority. This was to make it easy for multiple people to work on the same project simultaneously. Further to make it simple, and easy to understand and navigate for the residual group members, without needing to school each other in the different software aspects.
A directory was put into place including both MainVI's and SubVI's where the name and logo of each were filled out. Everything was categorized and numbered accordingly.
The different categories are:
1. Main Vi
2. Controlling SubVI
3. Sensor SubVI
4.Sample Taking SubVI
5. Other
This made it easy to find the different subVi's and determine which subVI's interact, because they where all in the same category. Being able to transfer this to the project application in LabVIEW was perfect and made the whole software very structured, even though it includes 3 mainVI's, 47 subVI's, and 2 different libraries with a total of 45 shared variables.
Snapshot from the report which includes to total list of VI's
The Software
The software is split up into two separate project libraries:
- A ground station - where the user controls and monitors the boat.
- The boat - where the myRIO controls all the boats functions such as sailing, sample taking and sensor information gathering.
User Interface on Ground Station
The main loop functions as the brain of the boat.
The setup is a state machine with 5 states (Wait, Start up, Sailing, Sampling and End). In each
state there can be multiple other states. All information from the other loops is processed here which leads to the determination of what the boat should do and where it is going.
Main loop on the boat - the brain of the project
Through two xBee's the ground station and boat are able to send data, information and commands. This is done by building its own command library with custom lines of strings that are compiled and sent back and forth via WiFi. The setup is the same in both projects to save time and makes it easier to expand.
Two while loops for sending and receiving - data and commands are sent out using shared variables.
The boat has two modes, manual control and autonomous mode. While in autonomous mode or AI, as it is called in the program, it steers using both compass and GNSS positioning to determine its heading towards a predefined point. In the case of obstacles the boat will override the regular direction control commands and avoid the object if it is in its path.
Autonomous steering and avoidance
The Conclusion:
The product solves the task of automating sea surface microlayer sample taking, hereby also making it safer, less labor-intensive, and quicker for scientists. This will help speed up the collection of SSM done by a single scientist by 75%, and greatly improve the research on the environmental impact
of the SSM.
After finishing the project the prototype has successfully been tested in Denmark, before being handed over to the biologists. They are currently validating and learning to use it before it be goes to Greenland to sample the SSM there.
Throughout the entire project a lot was learned - at the beginning of the project we were nervous about being able to finish in the allocated time and with the knowledge we had. The deeper we dived into the project both building the prototype and developing the software the more interesting it got. More and more time was spent on discovering new ways to make certain components and to perfect the individual parts being built. In the end we are very happy with how it turned out.
Based on the research done by the biologists and the ABLS, a scientific paper is being written to highlight the environmental impact of SSM and the method developed in this project.
Time to Build:
The project started on January 28th 2019 and ended May 22nd 2019. A total of almost 4 months. The project was split up into 4 separate sections and the time spent on each section is shown below. This is the time used by the 5 group members in total.
System specification: 200 hours
Design & Plan: 75 hours
Build and program: 400 hours
Test & Demo: 150 hours
Afterwards: 25 hours
Total: 850 hours
Pictures taking during the project:
SolidWorks assembly of the prototype
The boat while on mission
The boat docked at the harbor - opened up to insert batteries
The box seen from above
The box - ready for deployment
The group - from left to right: Niels, Mikkel, Silas, Troels & Jonas
