Projects:2014S1-57 Autonomous Vehicle Technologies

This project is to produce the practical component of a new robotics course. It will involve students individually designing, building and testing their own autonomous vehicle (AV). This practical will give students the opportunity to develop highly useful and sought after skills, such as CAD design, 3D Printing, Altium designer, PCB prototyping and microprocessor coding. Developing these skills through practice rather then theory will set future students in good stead for their future career.

Project information

Background

In a constantly expanding and changing engineering industry it is always important to keep students' skills up to date with what they will see out in the workforce. Currently there are many robotics projects that use system engineering in them, but these are usually group projects. As a result students may not gain the full learning experience that they could from system engineering as only smaller sections may be delivered to them. If students worked on smaller system engineering projects as individuals they would gain a higher understanding of all the elements that encompass the project and force them to work outside their comfort zones.

Objectives

First to prove that this practical is feasible. By providing examples of what we expect future students to achieve. This required us to design and develop our own individual AVs as proof of concept.

Second we produced resources and guides for future students. This is in the form of: documentation, gathering resources, taking notes of our experiences and developing design guidelines and procedures.

Quadcopter

The multi-rotor system with four propellers and GPS navigation function is chosen for this project, since it requires high level system design and involves different skills such as PCB making, CAD drawing and programming. This quadcopter is based on Arduino platform, where by referencing the open source project MultiWii[1]to build the flight controller and using its GUI to adjust flight attitude.

The different version of Flight Controller(FC) as shown, by testing them, only the latest version is working properly.

different version PCB

The initial design is to use IR sensors sensing around environment and then performing the automatically obstacle avoiding fly. However, due to the memory size limitation of Arduino mini micro-controller and its indoor flight characteristic,this design is abandoned.

Initial Design Schmatic

The final design is to using GPS and ultrasonic sensor navigation board to perform the auto plight. At low altitude, Quadcopter using ultrasonic sensor to land and hover, where at high altitude the GYO and GPS combination enables the quadcopter flying along predetermined way points.

Some challenges are:

• Flight Controller(FC): Must be compatible with different sensors, as well as have good performance to keep the quadcopter stable.
• Algorithm design and coding: The PID algorithm has been selected.
• Navigation board : The GPS and ultrasonic sensor are allocated on separated PCB, hence the serial communication with FC is another challenge.
• System integration: All components must be able to combine together.

Components:

• HC-SR04 ultrasonic distance sensor is used
• The four brushless motors must be included, so the Electric Speed Controllers (ESCs) are needed.
• For the brushless motors the KV value will be around 1000KV with 40A ESC are selected to drive the 10 inch propellers.
• For the frame, during this design stage, it would be done by 3D printing.

AV Search Boat

The goal of the AV is to be a small scale boat capable of mapping obstacles over water. Using a combination of an accelerometer and magnetometer the craft is capable to keeping track of its location. Using IR Proximity it can detect upcoming obstacles and change its own path to avoid them. The craft will act as a platform for future development, incorporating additional sensing capability allowing for more flexible usage.

Possibile future applications include search and rescue operations, environment damage monitoring and driverless transport applications.

Auto Tank

This AV's purpose is a simple collision avoidance tank. It has a rectangular aluminium chassis, that has a variety of mounting holes positioned on it. The wheels are plastic with a rubber tread running between two of the wheels on either side of the chassis. It uses a proximity sensor at the front of the AV to sense an obstacle in front of it and, using its microcontroller, can avoid the obstacle. The size of this AV is small scale to provide a simple and low budget design while still complying with our set requirements. The aluminium chassis gives it a strong casing and also allows for further expansion on its functionality.

Auto Tank Block Diagram.

To incorporate all of the electronic components into one system a PCB was designed in Altium. This process had a few trial an error phases where the physical layout of the PCB needed to be revised a number of times. When producing the layout of the PCB a few factors where taken into account, firstly it needed to be small to fit inside the Tank's chassis. Secondly the connections between pads needed to be relatively simple to avoid having a cluster of overlapping lines. This was achieved by placing the motor driver in the opposite direction to the microcontroller to provide simple connections between them. Thirdly the lines that the motors are directy connected to needed to be made thicker just in case they started drawing more power than expected and to protect the circuit.

Auto Tank PCB Schematic.

Auto Tank PCB Layout.

Motor Driver Wiring Diagram.

Practical Resources

During this project a number of resources were developed that will help aid students undertaking this practical.

- Firstly a common components checklist was developed to give students the chance to make sure that their AV's meet all of the requirements of this practical and also to give them a clear view of their own AV. The document is a large table with main sections that can be completed by selecting one of more of its proceeding sub-sections.

- Another document that has been produced is a flow chart that will give students a guide through their design and building process. Students may choose to follow their own pathway but this chart will help keep them from straying from their main goals and help them if they get stuck.

- A document outlining common problems and pitfalls has been produced that students can use in conjunction with the flow chart to help keep them from running out of time or budget or getting stuck.

- A list of recommended component stores was also developed to give students an idea of places they could go for parts. A few of them were used in our own example AVs while some others were also found. Some of the stores are local to Adelaide.

Personnel

Team Members

• Mr. Clayton Jericho
• Mr. Hualong Sun
• Mr. Patrick Ward

Supervisors

• A/Prof. Nesimi Ertugrul
• Dr. Braden Phillips

Awards

This project was awarded the "SA Power Networks Best Electrical Technology Project Exhibit" at Ingenuity 2014.