Aspects of Robotics – Mobile Robot (Hardware)


Mobile Robot Construction and Programming
1 Introduction

As part of this lab students are provided with mobile robot kit
(DEXTER). The robot is a differential wheeled mobile robot
capable of moving in an obstacle-cluttered environment. It can
translate linearly and rotate on the spot. It has two wheels that can
be driven independently and an additional, passive ball castor wheel
for stabilisation. A microcontroller is available; it provides
communication links and can be programmed to achieve navigation
tasks. In addition, incremental shaft encoders for motion
control and ultrasonic range sensors to measure the
distance to obstacles in the vicinity of the robot are

2 Aim

The aims of this laboratory are to become familiar with
the functioning of a mobile robot, to learn how to write
navigation programs for the robot, and to investigate the
robot’s performance in a real environment in contrast to a
simulated environment.

3 Lab overview

1) An introduction to the provided mobile robot will be given. The students will be informed
about the robot’s design, specifications and applications.
2) The students will be taught how to operate the mobile robot using a microcontroller-based
system and to conduct basic experiments.
Figure 1: The DFRobot 2WD Mobile Platform.
Top: Kit components. Bottom: Assembled robot.

Aspects of Robotics – Mobile Robot (Hardware) – October 17

4 Tasks

1) Become familiar with the communication protocol of the Microcontroller. Upload simple
programs on to the Microcontroller and ensure that you can execute your programs on the
Microcontroller. Make use of relevant websites to develop your programs. Use the
Microcontroller development environment to upload your programs to the Microcontroller.
2) Try to use the Microcontroller to read simple sensor inputs such as those coming from a
pushbutton or an ultrasonic sensor.
3) Try out the provided ultrasonic sensor and carry out distance measurements using this
sensor. How accurate is it?
4) Connect the sensors and actuators of the robot to the Microcontroller.
5) Run an obstacle avoidance program on the robot-based Microcontroller and conduct

5 Report

Please submit a report based on this lab (recommended number of pages: 15).
1) Describe the different stages needed to program and interface a Microcontroller.
2) Describe the experiments conducted using the ultrasonic sensor. Explain the results.
3) Briefly describe the behaviour of the tested navigation algorithms based on your
observations during program execution and/or study of the provided programs.
4) Relate the algorithms tested on your robot to the navigation algorithms presented as part of
the lecture course. Explain what the differences are between your algorithms and those
presented in class (if there are any). Discuss limitations of your algorithms. This is a chance
to explain why something didn’t work; please make suggestions on how encountered
problems could be overcome.
The deadline for the submission of your report will be announced in class and on QM+.
Submit your report online before the given deadline.

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