AFRL Jetyak Documentation

Autonomous Field Robotics Lab (AFRL)

Jul 12, 2018

Contents

1 Introduction to AFRL Jetyak 31.1 Jetyak Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Autopilot Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 6+ Channel RC Transmitter and Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 GPS module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.5 Battery and Charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61.6 Ground Control Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.7 Optional Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Initial Setup 13

3 Assembly Instructions 15

4 Power Planning and Installation 17

5 Sensor Planning and Installation 19

6 Maintenance 21

7 Applications 23

8 Appendices 25

9 License 27

10 Help 2910.1 Need further help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

11 Indices and tables 31

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AFRL Jetyak Documentation

AFRL Jetyak is an autonomous surface vehicle (ASV) designed by Autonomous Field Robotics Laboratory (AFRL)at University of South Carolina for marine surface explorations.

The CPSD (Coastal Processes & Sediment Dynamics) lab is where the first prototype was created in the summer of2015.

AFRL jetyak is MOKAI kayak cite{mokai} with that provides completely autonomous and semi-autonomous controlthrough remote controller. This system is well suited for long distance marine surface explorations and area coverage.

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AFRL Jetyak Documentation

2 Contents

CHAPTER 1

Introduction to AFRL Jetyak

1.1 Jetyak Components

While it is likely possible to implement this design using comparable components to the ones listed below, we chosethese components due to the availability of existing documentation and prior experimentation from the large populationof Pixhawk users.

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The first main component is of course the Mokai ES-Kape with quick attach components.

There are several structural modifications to the factory shipped boat required to support our end-state design. Thesestructural modifications are documented in a standalone document by our structural engineer. :red: PLACE HOLDERFOR LINK TO GEORGE’S DOCUMENTATION OF THE MACHINE SHOP MODIFICATIONS FOR THE FLOOR,BATTERY AND BOX HOLDERS, AND MAST MOUNT.

1.2 Autopilot Hardware

After researching the few consumer off-the-shelf (COTS) autopilot platforms available, we selected the Pixhawk dueto its high reliability rating and robust capabilities without need for numerous peripheral support devices.

As our research team will be creating robot vision applications as well as depth and sonar sensor applications, we willalso use a separate companion computer running or Linux with a ROS node and MAVROS for processing sensor dataand sending control messages to the Pixhawk for controlling the Jetyak. This setup has been proven on ground and airplatforms to be capable of running both robot control and the sensor processing code.

For more support to augment this tutorial, be prepared to read many topics specific to the flight control communitythat the Pixhawk and its autopilot components were originally designed to support.

Note: Parts required and detailed diagrams and schematics will be documented and referenced in appendices to thistutorial.

1.3 6+ Channel RC Transmitter and Receiver

You’ll need a radio control transmitter to manually control your Jetyak and to activate its control modes. You can useany RC transmitter/receiver system with at least 6 channels, however due to the robust capabilities and highly flexibleprogramming capabilities, our team has chosen the Fr Sky Taranis X9D Radio with D8R-XP with PPM control tominimize cabling and ports between the radio receiver and Pixhawk.

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AFRL Jetyak Documentation

Do not get one designed for cars (with a steering wheel and throttle trigger). The goal is not be driving the Jetyakmanually, but only to have an override mechanism, should conditions dictate. If you’re on a budget, the Turnigy 9x($54) is a popular choice. If you’d like better quality, we chose the Taranis FrSky Radio, and this tutorial will befocused on its implementation.

1.4 GPS module

Your Jetyak will require a GPS module. The module used in this project and described in this tutorial is the RadiolinkSE100 GPS Module for Pixhawk, which replaced the 3DR UBlox GPS + Compass Module, both of which include acompass that Mission Planner recognizes and uses as a secondary compass to the one in the Pixhawk.

1.4. GPS module 5

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1.5 Battery and Charger

You’ll also need a stout battery to run all the additional onboard hardware separate from the factory battery that comeswith the Mokai ES-Kape, and a charger. In our case we chose a 12V, 35AH battery from MightyMax to power allnon-factory components of the Jetyak. You find all the conditioning, fusing, and protection steps and specificationswe took in the power configuration section of initial setup.

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1.6 Ground Control Station

The (free and open source) Mission Planner is required if you’re going to be loading new versions of Rover onto theautopilot controller, and for first-time tuning and calibration. At current time, Mission Planner uses the Rover templateto setup initial parameters to be as close as possible to the requirements for operating a boat. It runs on a PC and canalso be used for planning missions. One detailed section of this tutorial will cover the initial setup of Mission Plannerand the step-by-step modification of the Rover parameters to allow control of your jetyak.

At this point, you could test, build, program, and control a pseudo-autonomous Jetyak, which would be capable offollowing missions programed through mission planner software and relayed to the jetyak via waypoint navigationcommands. However, if seeking to explore the world of true autonomous operation, where you can program decisionmaking for an onboard autonomous controller, then you will need the following “optional” hardware.

1.7 Optional Hardware

1.7.1 Telemetry Radio

A telemetry radio allows your jetyak to communicate with your ground station remotely using the MAVLink protocol.This allows you to interact with your missions in real time and receive streaming data from your vehicle’s camerasand other components. This adds considerable convenience to your missions. RC grade solutions, like the one belowwill meet the needs of many.

1.6. Ground Control Station 7

AFRL Jetyak Documentation

However, in our case, we want the capability to send and receive large swaths of sonar, weather, depth, and robothealth data at long ranges during missions. The COTS solution is for RF modems to be deployed and programmedinto the overall design. We have selected the RF900+ modems from RFDesign in Australia, along with all supportinghardware listed in the equipment appendix, to accomplish this task.

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1.7.2 Sensors

Sonar/Depth are recommended to aid in underwater obstacle avoidance and mapping the environment. After attempt-ing to reverse engineer some proprietary transducers from Garmin and Humminbird, we chose NMEA 0183 CruzProAT120-P sensor due to its relatively inexpensive cost and the simplicity of reading the desired data fields directly fromits serial output, without proprietary drivers.

1.7. Optional Hardware 9

AFRL Jetyak Documentation

Anemometer, or wind sensor is useful in measuring instantaneous wind speed and direction on the vessel. Informa-tion collected can be used to map the environmental wind patterns and predict nearby wind dynamics. We chosethe Sparkfun weather station, which is easily controlled through an Arduino Uno with a transceiver riser board toaccommodate the RJ11 connections to the wind direction, wind speed, and rain gauge (unused in our implementation)sensors. Precise wiring, soldering and programing instructions and code are included in the sensor portion of thistutorial.

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AFRL Jetyak Documentation

Water current speed sensors is the most vital and challenging of the sensors to employ. While there are acousticdoppler current profilers (ADCP) available, their price excludes them from our goal of maintaining an inexpensiveimplementation. The obvious choice is to employ reliable and long existing technology of hall effect sensors mountedin a waterproof housing which sends an interrupt signal to an Arduino each time the magnet passes the gate. TheArduino simply converts the circumference of the wheel along with the number of interrupts per time slot into alinear velocity. Again after finding the frequencies and voltages of proprietary sensors of hummingbird to be outsidethe ranges of our 5V Arduino-based sensor group, we focused on a more open source solution and arrived at theST800/P120 paddle wheel sensor from Raymarine. Again, the modifications, build, testing, and calibrations conductedwith these sensors is included in the sensor chapter.

1.7. Optional Hardware 11

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Combining the measurements of these sensors together enables and wholistic mapping of dynamic environmentswhich in turn enables us to develop strategies for entering such environments as well as implement controls once in adynamic environment for the ASV to maintain precise and efficient control. ADD Sensor Node, power distribution,mast sensor mounts, underwater sensor mount and poles, splash guards (3).

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CHAPTER 2

Initial Setup

Simple license example

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14 Chapter 2. Initial Setup

CHAPTER 3

Assembly Instructions

Text for instructions

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16 Chapter 3. Assembly Instructions

CHAPTER 4

Power Planning and Installation

Other text goes here.

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18 Chapter 4. Power Planning and Installation

CHAPTER 5

Sensor Planning and Installation

Text text text

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20 Chapter 5. Sensor Planning and Installation

CHAPTER 6

Maintenance

Anything goes here???

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22 Chapter 6. Maintenance

CHAPTER 7

Applications

Describing the multi-robot coverage and referenceing to it.

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24 Chapter 7. Applications

CHAPTER 8

Appendices

Here the schematics can be included.

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26 Chapter 8. Appendices

CHAPTER 9

License

Simple license example

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28 Chapter 9. License

CHAPTER 10

Help

Another file example

10.1 Need further help

Please join us

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30 Chapter 10. Help

CHAPTER 11

Indices and tables

• genindex

• modindex

• search

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