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User Manual
Quanser Qbot
Quanser Qbot: User Manual
Table of Contents
1. Introduction..........................................................................................................................1
2. Prerequisites.........................................................................................................................2
3. References............................................................................................................................2
4. System Hardware Description.............................................................................................3
4.1. Qbot round Vehicle....................................................................................................3
4.1.1. The iRobot Create®.............................................................................................3
4.1.2. The Printed Circuit Board (PCB).........................................................................4
4.1.2.1. Digital Input/Output Pins (DIO #)................................................................5
4.1.2.2. umstix IR Serial Pins.................................................................................5
4.1.2.3. SW/nSW and INT/EXT Jumpers..................................................................6
4.2. Detailed Description of Qbot Components..................................................................6
4.2.1. Qbot DAC............................................................................................................6
4.2.2. USB Camera.........................................................................................................6
4.2.3. umstix................................................................................................................7
4.2.4. Battery..................................................................................................................7
4.2.5. Infrared Sensors....................................................................................................8
4.2.6. Sonar Sensors.......................................................................................................9
4.3. System Specifications and Model Parameters.............................................................9
5. System Setup........................................................................................................................9
5.1. Setting up the Qbot....................................................................................................10
5.2. Establishing Wireless Connection..............................................................................10
5.3. QUARC – Quanser Real-Time Control.....................................................................10
5.4. Using the on-board camera........................................................................................17
6. Troubleshooting uide.....................................................................................................18
6.1. Qbot Drive or Direct Drive commands aren't responding or are causing the robot to
move incorrectly, or the Qbot bump sensor inputs are not functioning............................18
6.2. The model fails to build/connect or the QUARC console does not successfully open..
19
6.3. The Qbot sensors are not being read correctly or they are stuck at some constant
value..................................................................................................................................20
6.4. The Qbot magnetometer values drift while the Qbot is moving in a straight line.....20
6.5. The Simulink model appears to run slowly (i.e., the simulation time runs slower than
actual time), or the console displays the message “Sampling rate is too fast for base rate”.
...........................................................................................................................................21
6.6. Trying to start the Qbot model results in the error “Unable to locate the dynamic link
library or shared object.”...................................................................................................21
6.7. The LEDs QBOT POWER and UMSTIX POWER do not illuminate when the
Qbot robot is powered on..................................................................................................22
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Quanser Qbot: User Manual
6.8. Building a model fails with the error “Not enough system resources are available to
perform the operation.” The hard disk is full on the umstix computer..........................22
6.9. The Display Image block is not showing any image..................................................22
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Quanser Qbot: User Manual
1. Introduction
The Quanser Qbot (Figure 1) is an innovative autonomous ground robot system
incorporating a robust educational ground vehicle with the Quanser Controller Module
(QCM). The vehicle is comprised of a iRobot Create® robotic platform, an array of optional
infrared and sonar sensors, and a Logitech Quickcam Pro 9000 USB camera. The QCM is
an embedded system mounted on the vehicle, which uses the umstix computer [2] to run
QUARC, Quanser's real-time control software, and the Qbot data acquisition card (DAC).
The interface to the QCM is MATLAB Simulink with QUARC. The Qbot is accessible
through three different block sets: the Roomba block set to drive the vehicle, the HIL block
set to read from sensors and/or write to servo outputs, and finally the OpenCV block set to
access the camera. The controllers are developed in Simulink with QUARC on the host
computer, and these models are downloaded and compiled into executables on the target
( umstix [2]) seamlessly. A diagram of this configuration is shown in Figure 2.
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Figure 1: The Quanser Qbot - top view
Quanser Qbot: User Manual
Section 2 goes through the laboratory requirements, and Section 3 lists various documents
that are referenced in this manual. The general system description, component
nomenclature, specifications, and model parameters are all given in Section 4. Section 5
goes into detail on how to setup the Qbot. Lastly, Section 6 contains a troubleshooting
guide.
2. Prerequisites
To successfully operate the Qbot, the prerequisites are:
i) To be familiar with the components of the Qbot.
ii) To have QUARC version 2.2 or later installed (NOTE: You must install the beta
components by selecting them during installation, since some blocks used with
the Qbot are found in the QU RC beta library) and properly licensed.
iii) To be familiar with using QUARC to control and monitor the vehicle in real-time,
and in designing a controller through Simulink. See Reference [2] for more details.
3. References
[1] Gumstix:
http://gumstix.com/
[2] QUARC User Manual (type doc quarc in Matlab to access)
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Figure 2: Communication Hierarchy
Quanser Qbot: User Manual
[3] iRobot Create Open Interface Specification Sheet
[4] iRobot Create Owner's Guide
[5] S ARP 2Y0A02 IR Range Sensor.pdf
[6] LV-MaxSonar-EZ0-Datasheet.pdf
4. System ardware Description
4.1. Qbot Ground Vehicle
4.1.1. The iRobot Create®
The Qbot uses an iRobot Create® frame (Figure 3). The Qbot follows the Quanser standard
for body frame axes, where the x-axis is in the forward direction, the y-axis is to the left, and
the z-axis is up. The diameter of the vehicle is 34 cm, and its height (without camera attach-
ment) is 7 cm. and it is driven by two differential drive wheels. The iRobot Create® comes
with a bumper sensor and an omni-directional infrared receiver. The QCM can access data
from these sensors.
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Figure 3: Anatomy of the Qbot, showing various components and body axes
Quanser Qbot: User Manual
The Qbot is turned on by pressing the power button (more on Section 5.1). Figure 4 below
shows the buttons that are used to operate the iRobot Create®. The Play and Advance but-
tons are for built-in demos for the vehicle, and are not necessary for Qbot purposes.
4.1.2. The Printed Circuit Board (PCB)
The printed circuit board (PCB) contains the wiring and circuitry for the Qbot. It also acts as
a cover for the DAC and umstix, and mounts for infrared sensors, sonar sensors, and web-
cam. Figure 5 shows the accessible pins for the user. In particular, the DIO, PWM output,
and analog input pins have been labeled for clarity.
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Figure 4: Buttons on the Qbot Frame
Quanser Qbot: User Manual
4.1.2.1. Digital Input/Output Pins (DIO #)
The DIO channels (0 to 6) are set as inputs by default. The DIO channels need to be con-
figured as either inputs (or outputs, but not both) using the HIL Initialize block. Also, if an
output needs to be in a known state on power up, it is recommended that a 10k resistor is
put from the I/O to 5V or ND as needed.
There is a final digital channel (7) that is a fixed output, and it is represented by an LED
labeled DIO7.
4.1.2.2. Gumstix IR Serial Pins
The Qbot provides a TTL serial connection to the umstix IR serial port (port number 2).
The serial port consists of ground ( ND), receive ( UMSTIX IR RXD), transmit ( UM-
STIX IR TXD), and power (+3.3V or +5.0V) pins. The serial port is accessed through the
QUARC Stream blockset or Stream API. For more information on accessing serial data see
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Figure 5: Qbot PCB showing available pins for the PWM output, Digital Input/Output
and Analog Input pins, serial pins, and jumpers for INT/EXT power
Quanser Qbot: User Manual
the QUARC help QUARC Targets/User's uide/Communications.
4.1.2.3. SW/nSW and INT/EXT Jumpers
The INT/EXT jumper switches the Qbot from internal power from the iRobot Create battery
(INT) and an external battery power supply (EXT). Note that no external battery is supplied
with the Qbot, so this jumper should be left in the INT position to power the Qbot. When
the power source jumper is in the INT position, the SW/nSW jumper indicates whether the
iRobot Create must be switched on (SW) for the Qbot to receive power, or whether the Qbot
should always draw power even when the iRobot Create is off (nSW).
4.2. Detailed Description of Qbot Components
4.2.1. Qbot DAC
The Qbot DAC is a data acquisition board, capable of receiving analog inputs and other in-
puts (for sonar sensors). It is also capable of writing PWM outputs for possible servo actuat-
ors. It is located underneath the black cover of the Qbot, and it is not intended for it to be
physically accessed.
4.2.2. USB Camera
The Logitech Quickcam Pro 9000 USB camera is mounted on top of the Qbot (Figure 6).
The QUARC block set that uses the Open Source Computer Vision library (in Section 5.3)
allows the user to capture and display images in real time, process them, and save them in a
disk for future analysis.
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Figure 6: Camera
Quanser Qbot: User Manual
4.2.3. Gumstix
The umstix is a small-scale, fully functional, open source computer. With QUARC in-
stalled, code generated from MATLAB is downloaded, compiled, and executed directly on
the umstix.
The umstix motherboard is connected directly to the Qbot DAC. The umstix also comes
with the Wifi attachment board to allow wireless connection between the target umstix
and the host computer and/or other vehicles.
The IP of the umstix will be provided.
4.2.4. Battery
The Qbot is powered by the Advanced Power System (APS) Battery (Figure 7) provided by
iRobot. The battery fits underneath the Qbot (Figure 8), and can last continuously for about
2 hours after a full charge. The Qbot's power light indicates the power level of the battery.
The light is green when the batteries are fresh, then gradually turns red as the battery
discharges. The battery takes less than 3 hours to charge. While charging, the power light
pulses slowly with an orange colour. A battery charger will be provided.
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Figure 7: The Qbot Battery, the Advanced Power System
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