MobileRobots Pioneer Arm User manual

Pioneer Arm Manual
with NEW!
AKIN Arm Kinematics Software

© 2007 MobileRobots Inc. All rights reserved.
This document, as well as the software described in it, is provided under license and may only be used
or copied in accordance with the terms of the respective license.
Information in this document is subject to change without notice and should not be construed as a
commitment by MobileRobots Inc.
The software on disk, CD-ROM and firmware which accompany the robot and are available for network
download by MobileRobots customers are solely owned and copyrighted or licensed for use and
distribution by MobileRobots Inc.
Developers and users are authorized by revocable license to develop and operate custom software for
personal research and educational use only. Duplication, distribution, reverse-engineering or
commercial application of MobileRobots software and hardware without license or the express written
consent of MobileRobots Inc. is explicitly forbidden.
PeopleBot™, AmigoBot™, PowerBot™, PatrolBot™, ARCSinside™, SetNetGo™, MobilePlanner™,
MobileSim™ and MobileEyes™ are trademarks of MobileRobots Inc. Other names and logos for
companies and products mentioned or featured in this document are often registered trademarks or
trademarks of their respective companies. Mention of any third-party hardware or software
constitutes neither an endorsement nor a recommendation by MobileRobots Inc.
Pioneer Arm Manual ●Version 7.1 ●January 2007
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MobileRobots Inc.
Important Safety Instructions
9Read the installation and operations instructions before using the equipment.
9Avoid using power extension cords.
9To prevent fire or shock hazard, do not expose the equipment to rain or moisture.
9Refrain from opening the unit or any of its accessories.
9Keep equipment away from hair or fur.
Inappropriate Operation
Inappropriate operation voids your warranty! Inappropriate operation includes, but is not limited to:
9Dropping the equipment
9Overloading the Arm above its payload capacity
9Getting the equipment wet
9Continuing to run the equipment after hair, yarn, string, or any other items have become
wound in one or more of its joints
9All other forms of inappropriate operation or care
Use MobileRobots authorized parts ONLY;
warranty void otherwise.
iii

Table of Contents
CHAPTER 1 INTRODUCTION ..................................................................................................................... 1
THE PIONEER PLATFORM ............................................................................................................................ 1
THE PIONEER ARM..................................................................................................................................... 1
CONTROL HARDWARE AND SOFTWARE ......................................................................................................... 2
ARM PACKAGE .......................................................................................................................................... 2
Basic Components (all shipments)....................................................................................................... 2
User-Supplied Components / System Requirements.......................................................................... 3
ADDITIONAL RESOURCES ............................................................................................................................ 3
Software ................................................................................................................................................. 3
Newsgroups ........................................................................................................................................... 3
Support................................................................................................................................................... 4
CHAPTER 2 INSTALLATION & OPERATION .............................................................................................. 5
MOUNTING THE ARM TO YOUR PIONEER ROBOT............................................................................................. 5
POWER TO THE ARM................................................................................................................................... 6
Arm Safely at HOME .............................................................................................................................. 6
CONFIGURATION ........................................................................................................................................ 6
ARM AND ARM KINEMATICS DEMONSTRATIONS ............................................................................................ 7
P2ArmDemo........................................................................................................................................... 7
ArmServer and ArmApplet.jar ............................................................................................................... 7
SAFETY WATCHDOGS.................................................................................................................................. 8
Power and Connection-Related Automatic Shutdown ........................................................................ 8
Timed Shutdown.................................................................................................................................... 9
Gripper Release Timer .......................................................................................................................... 9
Warm Reset ........................................................................................................................................... 9
CHAPTER 3 SOFTWARE AND PROGRAMMING ..................................................................................... 10
Generic versus Server Programming..................................................................................................10
GENERIC CONTROLS................................................................................................................................. 10
Generic Command Syntax...................................................................................................................10
Generic Commands.............................................................................................................................10
Generic Command Communications .................................................................................................11
PIONEER CONTROLLER ARM SERVERS ....................................................................................................... 11
Client Commands ................................................................................................................................11
INFO and ARMINFOpac .......................................................................................................................12
POWER .................................................................................................................................................12
STATUS and ARMpac ..........................................................................................................................13
SPEED and POS ...................................................................................................................................13
SPEED Limits .......................................................................................................................................14
HOME and PARK.................................................................................................................................14
INIT, CHECK, and Warm Reset Protocol.............................................................................................14
ARIA AND ARAKIN ARM SUPPORT............................................................................................................ 15
ArP2ArmSimple, ArAKinDemo and ArAKinExample .........................................................................16
CHAPTER 4 ARM FLASH PARAMETERS................................................................................................ 17
FIRMWARE TOOLS AND PARAMETERS ........................................................................................................ 17
Installing the FLASH Utilities...............................................................................................................17
CONFIGURING PIONEER ARM OPERATING PARAMETERS............................................................................... 17
Step 1. Serial Connection from Computer to Robot..........................................................................18
Step 2: Enable FLASH (C166 only).....................................................................................................18
Step 3: Put Controller into Maintenance Mode (P2OS and AROS only)...........................................18
Step 4: Run the cf Program ................................................................................................................18
Step 5: Changing Arm Configuration Parameters .............................................................................19
Step 6: Save Your Work.......................................................................................................................19
EDITING THE ARM PARAMETERS ................................................................................................................ 19
CHAPTER 5 MAINTENANCE & REPAIR..................................................................................................21
FACTORY REPAIRS ................................................................................................................................... 21
APPENDIX A............................................................................................................................................. 22
WARRANTY & LIABILITIES...................................................................................................................... 23
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MobileRobots Inc.
Figure 1. The Pioneer Arm on
a 3-DX
IntroductionChapter 1
Congratulations on your purchase of MOBILEROBOTS’ multi-jointed
robotic arm for the Pioneer family of mobile robots.
This manual provides both the general and technical details you
need to operate your Pioneer Arm and to begin developing your
own control software integrated with other mobile robot
activities.
The Pioneer Platform
Pioneers are small, intelligent mobile robots. The basic Pioneer platform contains all of the
components of an intelligent mobile robot for sensing and navigation in a real-world environment,
including battery power, drive motors and wheels, position encoders, and range-finding ultrasonic
sonar transducers—all managed via either a Siemens C166-, an Hitachi H8S-, or a Renesas SH2-based
controller board.
Pioneer DX models are two-wheel, differential-drive mobile robots intended for indoor, albeit less-than-
ideal surface operation (wheelchair accessible areas, for example). Performance PeopleBot™, too, is
a Pioneer differential-drive robot. Its tall body is for human interaction studies and applications. The
Pioneer AT is a four-wheel drive, differential skid-steering version intended for outdoor, all-terrain (AT)
operation. Technically, the Pioneer platforms are nearly identical and share accessories, including the
Pioneer Arm.
All Pioneer robots come with onboard robotics server software. These operating systems have an
open API for client control of the robot’s systems and accessories. Users access the onboard servers
through an RS-232 serial communication port from their client workstation connected wirelessly, or
tethered via a piggyback laptop or integrated onboard PC. See your robot’s Operations Manual for
details.
The Pioneer Arm
The Pioneer Arm is a relatively low-cost robot accessory for use in research and in the classroom.
Driven by six open-loop servo motors, the five degrees-of-freedom (5-DOF) Pioneer Arm’s end-effector
is a gripper whose foam-lined fingers allow for firm grasp and manipulation of objects as large as a
soda can and as heavy as 150 grams throughout the arm’s envelope of operation.
Joints include:
9rotating base
9pivoting shoulder
9pivoting elbow
9rotating wrist
9pivoting gripper mount
9gripper fingers
All servo-driven joints, except for the gripper fingers, pivot or rotate at least 180 degrees. Mounted to
the front of the robot’s top plate, the Pioneer Arm has a very wide envelope of operation, reaching 50
centimeters from the center of its rotating base to the tip of its closed fingers. The Pioneer Arm’s
reach, therefore, lets you pick up objects from the floor in front of your Pioneer robot and place them
on its back.
1

Introduction
Figure 2. The Pioneer Arm’s horizontal reach
Control Hardware and Software
The Pioneer Arm comes with its manufacturer’s PIC-based controller and servo-driver hardware and
software. These are housed inside the DX on top of the battery box or inside a special accessory box
that is mounted at the rear of the AT or Performance PeopleBot robot’s top-plate.1
The Pioneer Arm’s controller is attached to one of your robot controller’s AUX serial ports. Its
operation is supported by generic (“pass-through”) serial commands, as well as dedicated Pioneer Arm
servers as part of the controller’s embedded system software. Your client software communicates
with and controls the Arm through these servers.
Develop integrated robotics client software for the Pioneer platform overall and including the Arm with
MOBILEROBOTS’ Advanced Robotics Interface for Applications (ARIA). ARIA with ArP2Arm C++-language
sources comes with the robot as is available for updates and downloads from the MOBILEROBOTS
support website, http://robots.MobileRobots.com.
In addition, the Pioneer Arm now comes bundled with ARIA-integrated inverse kinematics software
(Arm Kinematics; AKin), as licensed from Fachhochschule Trier University of Applied Sciences. Simply
provide the 3-D position for the gripper end-effector and let AKin do the work. ARIA and ArAKin come
with several demonstration clients that you may modify and use to create your own mobile-robotic arm
software.
Windows® users also get standalone Arm Server software with a Java-based GUI demonstration
application (ArmServer and armApplet.jar) from Fachhochschule Trier.
Arm Package
Your Pioneer Arm is factory installed. Our experienced manufacturing staff put your Pioneer Arm and
its support accessories through a “burn in” period and carefully tested them before shipping the
products to you. We detach the Arm from the robot and ship them separately for safety.
Even though we’ve made every effort to make your Arm package complete, please check the
components carefully after you unpack them from the shipping crate.
Basic Components (all shipments)
9This manual
9Arm calibration sheet
9One fully assembled Pioneer 5-DOF Arm
9Arm control electronics, signal and power cabling installed in your robot
2
1Retrofitted DXs get the external control box, too.

MobileRobots Inc.
9Mounting hardware and cabling
9CD-ROM containing controller software for Arm support, Arm demonstration and development
software, and documentation
User-Supplied Components / System Requirements
9Tools for attaching the arm to the robot2
9Client-side PC and robot software
Additional Resources
All new MOBILEROBOTS customers get three additional and valuable resources:
9A private account on our Internet server for software, updates, and manuals
9Access to private robotics newsgroups
9Direct access to the MOBILEROBOTS technical support team
Software
Figure 3. Pioneer Arm's vertical reach
We maintain a 24-hour, seven-day per week Web server where customers may obtain software and
support materials:
http://robots.MobileRobots.com
Some areas of the website are restricted to licensed customers. To gain access, enter the username
and password written on the Registration & Account Sheet that accompanied your MOBILEROBOTS
platform.
Newsgroups
We maintain several email-based newsgroups through which robot owners share ideas, software, and
questions about the robot and accessories, such as your new Arm. Visit the support
http://robots.MobileRobots.com website for more details.
To sign up for pioneer-users, for example, send an e-mail message to the –requests automated
newsgroup server:
To: [email protected]
3
2The required tools, particularly the hex wrenches, come with the robot.

Introduction
From: <your return e-mail address goes here>
Subject: <choose one command:>
help (returns instructions)
lists (returns list of newsgroups)
subscribe
unsubscribe
Our SmartList-based listserver will respond automatically.
After you subscribe, send your email comments, suggestions, and questions intended for the
worldwide community of Pioneer users to the users group, NOT to the –requests address. For
example:3
To: [email protected]
From: <your return e-mail address goes here>
Subject: <something of interest to pioneer users>
Access to the pioneer-users newslist is limited to subscribers, so your address is safe from spam.
However, the list currently is unmoderated, so please confine your comments and inquiries to issues
concerning the operation and programming of Pioneer robots.
Tell us your robot’s SERIAL NUMBER.
Support
Have a problem? Can’t find the answer in this or any of the accompanying manuals? Or do you know
a way that we might improve our robots and accessories? Share your thoughts and questions directly
with us:
http://robots.MobileRobots.com/techsupport
Please include your robot's serial number (look for it beside the Main Power switch)we often need
to understand your robot's configuration to best answer your question. Your message goes directly to
the MOBILEROBOTS technical support team. There a staff member will help you or point you to a place
where you can find help.
3Notice that the –requests part of the email address is left out when sending messages to the newsgroup?
4

MobileRobots Inc.
Chapter 2 Installation & Operation
The Pioneer Arm’s control electronics and server software are factory installed and configured, but the
arm is detached and shipped separately for safety.
Mounting the Arm to Your Pioneer Robot
After carefully unpacking and inspecting the Pioneer Arm, robot, and accessories, manually fold the
Pioneer Arm into its HOME position. Then secure the Arm to the prepared top plate at the front of your
robot:
CAUTION
Always align your Pioneer Arm into it’s HOME position before use.
1. Put the Pioneer Arm into its HOME position: The tip of the Arm’s V-shaped mounting base should
point towards the rear of the robot, and the arm should be folded towards the back of its base.
2. Use the hex wrench that came with your robot and one of the mounting screws to secure the
arm’s base tip to the robot’s top plate just in front of the access port. Freely rotate the arm
around its base to access the mounting holes.
3. Align the two other mounting holes on each side and at the front of the Pioneer Arm’s base plate
with their respective holes on the robot’s top plate and secure with the provided mounting screws.
4. Mate with the signal and power connector attached to the arm with the one that comes up
through the robot’s maintenance port on the top plate. Insert wired harnesses back into the body
of the robot.
5

Installation & Operation
Power to the Arm
Power for the Pioneer Arm’s controller comes from your robot’s batteries, as switched by Main Power.
Power to the Pioneer Arm servo joints is normally OFF and only switched ON from software by toggling
a digital output port in the arm controller.
For power conservation and safety reasons, the arm-servo power relay normally is deactivated.
Accordingly, all the joints are limp and easily rotated and swiveled manually. When engaged, the servo
motors will resist your efforts to move them.
Figure 4. Your Pioneer 2 Arm safely at HOME
When the Pioneer Arm servos get
power, all joints simultaneously and as
quickly as possible jump to their
positions last programmed into the
arm’s controller. If power is removed
from the servos, all the joints fall into
their mechanically limpest position.
Since the Pioneer Arm’s joint positions
cannot be known, they are assumed by
their generic controller to be in a
default center position. When you
apply power to the servos, the arm
thereby snaps fully extended into a
“salute” nowhere near any reasonable
limp configuration. This snap-to-salute
draws excessive power and can swing
the joints into nearby objects. 4
Arm Safely at HOME
On start up or reset, your robot
controller’s Arm servers establish
communication with the Arm’s
controller and reset the joints to be in a low-energy, folded HOME position. When limp in that same
position, no joint is far from its HOME position when servo power gets applied. This way, the snap-to-
position jolts characteristic of servo motors when first powered up are minimized.
Accordingly, when operating the Pioneer Arm, be sure to manually place it in its HOME resting position
before applying power to its servos, and be careful to have it resume its HOME position before removing
power. Failure to do so may cause damage to the Pioneer Arm or to nearby people, animals, lamps,
vases, undergraduates...
For additional safety, the Pioneer Arm normally should ride on the moving robot in its HOME resting
position with servo power OFF, unless involved in manipulation activities. It only makes good sense to
protect the arm from damage and to conserve power; the servos draw precious battery power while
holding a position as well as while moving, and the Pioneer Arm can go dangerously limp if you
carelessly withdraw power from it.
Configuration
We normally install and configure the Pioneer Arm at the factory. During that process, we enable the
Pioneer Arm servers in your robot’s controller. And we calibrate each arm joint to arm-unique
maximum, minimum, center, and HOME positions. All these details are saved in your robot controller’s
FLASH parameters and recorded on a document that comes with your robot and arm. If you move the
Pioneer Arm to another robot or if you change controllers, you’ll need to reset that robot’s FLASH
configuration.
Please consult a subsequent chapter in this manual concerning editing the FLASH parameters, as
needed. Note here that with C166-based controller with P2OS, you need to set in FLASH the
6
4Some may argue that this presents a fine opportunity to perfect your robot’s “dope slap” maneuver made famous by Click and
Clack, the Tappet Brothers, on their infamous National Public Radio show, Car Talk©.

MobileRobots Inc.
ArmNumJoints parameter value to 6 and the auxbaud value to 0 (9600 baud). With AROS, set the
ArmPort parameter to 1 if the Pioneer Arm controller is connected via to the controller’s AUX1 serial
port, or 2 if connected to AUX2.
Similarly, with the latest ARCOS-enabled Pioneer robots, set the ArmPort parameter to 1 if the Pioneer
Arm controller is connected via to the controller’s AUX1 serial port, 2 if connected to AUX2, or 3 if it’s
attached to serial AUX3. In all cases, you need not set the related port’s baud rate since the Arm
servers automatically set the communication rate to 9600 baud.
Also note that an LED attached to the Pioneer Arm controller only flashes on and off when the arm is
properly attached, the Arm servers are enabled, and there are proper communications between the
Pioneer controller and the arm controller.
Arm and Arm Kinematics Demonstrations
Figure 5. The P2ArmDemo lets you operate the
Pioneer Arm quickly and easily.
Several Pioneer Arm demonstration programs and source files come on the CD-ROM that
accompanies the system. Use the P2ArmDemo executable with the keyboard arrows or a joystick to
select and move individual joints. Alternatively, steer the Arm kinematically with ArmServer and its
ArmApplet.jar demonstration GUI
(Windows only). Finally, see how to develop
robot-integrated Arm software with the
ArP2ArmSimple and ArAKinDemo sources in
ARIA.
Start up your robot. Its Pioneer Arm
automatically gets power, too, but the joint
servos should be OFF and the arm limp in its
HOME position. If not, manually move the
joints until the arm is in that HOME position.
P2ArmDemo
On startup, the P2ArmDemo program
automatically makes a client connection with
your robot’s controller through the COM1
(/dev/ttyS0 with Linux) serial port.5It then
graphically displays the Arm on your PC
screen along with a set of control buttons and
operating values.
Red dots indicate the current control joint.
Change joints by clicking the joystick fire
button, with the up or down arrow key, or by
clicking the mouse. Move the selected joint’s
position with the right or left arrow key or with the joystick (active when fire button pressed). Or click a
control button with the mouse to automatically center or move a joint to its center, home, maximum,
or minimum positions. Press the STOP! button or the space bar at any time to stop the Arm from
moving.
Deploy for Pickup sends the Arm around and to the floor, ready to pick up some item you may
place in its gripper. Carry Item sends the Arm up and around to place the item it has in its gripper
on the back of the robot.
The Arm servos automatically power up when you select to operate a joint. The Power Off button
automatically homes the Arm to its power off position.
ArmServer and ArmApplet.jar
7
5See your Pioneer 2 or Pioneer 3 Operations Manual for details on how to attach your PC to the robot and make a client-server
connection. If you get a start up error, please make sure the Pioneer Arm is properly attached and configured.

Installation & Operation
Forward and inverse kinematics
libraries now come with the
Pioneer Arm, as licensed from
Fachhochschule Trier University of
Applied Sciences. ArmServer.
exe is a Windows-only application
that lets you integrate the AKIN
arm-kinematics software with your
own, arm-specific applications.
ArmApplet.jar is a demonstra-
tion GUI for ArmServer.exe.
Figure 6. Connect ArmApplet.jar GUI to ArmServer to steer
the arm with AKIN-based kinematics.
Like P2ArmDemo, ArmServer.exe
makes a serial connection with
your robot controller, which in turn
makes a connection with the
Pioneer Arm. If you connect a PC
with the robot controller through
COM1, simply double-click
ArmServer.exe to launch it.
Otherwise, use a command window and append the ‘-rp <serial port>’ startup argument to the
command line, where <serial port> is the alternative communication port; COM3, for example.
Now start ArmApplet.jar, either on the same or on a PC elsewhere on the network. Enter the
network address of ArmServer’s Host: PC and click establish SocketConnection.6
Operate the arm by angles or by explicit x,y,z coordinates from the respective sliders. The arm
animation in the center of ArmApplet.jar reflects the motions. Click and hold the mouse for a few
seconds on any of the Park, Null, or Position 1 through 4buttons to capture the current arm
coordinates or angles. Click the button again later to have the arm achieve that configured position.
Safety Watchdogs
It is important to well manage the Pioneer Arm to minimize its power consumption and to protect it
and its surroundings from inadvertent damage. The robot controller’s Arm servers support important
features that monitor Arm activity and automatically, if enabled, act to protect your Pioneer Arm.
These watchdogs include a client connection-related automatic shutdown server, a release timer for
the Arm gripper, and a warm-reset server.
Power and Connection-Related Automatic Shutdown
Because it is attached to your Pioneer robot’s microcontroller, your client software may command and
control the Pioneer Arm only while it has an established client-server connection. Moreover, you must
explicitly software-command the Arm to power its servos: Its default state is in the HOME position with
servo power OFF.
With servo power ON and in a position other than HOME, the Pioneer Arm automatically returns to its
HOME position when your client software tells the arm servers to remove power from the servos.7
Otherwise, the arm might flop into an awkward and potentially damaging position when you remove
power to its positioning servos.
Similarly, the Arm servers automatically send the Pioneer Arm to its HOME position and remove power
from its servos immediately following severance of a client-server connection. See the CLOSE server
descriptions in your Operations Manual for more details about client-server connections.
The automated shutdown service may be disabled with a special client command and FLASH
parameter setting. See following chapters for details.
6The default localhost name typically works when running ArmServer and armApplet.jar on the same PC. Otherwise, enter
another hostname or IP address for ArmServer’s Host: PC on the nework.
8
7You may override some ARCOS/AROS/P2OS Arm servers with direct, generic Arm commands.

MobileRobots Inc.
Timed Shutdown
Another Pioneer Arm watchdog tests the amount of time that may lapse while the robot is connected
with a client PC and the Arm is in service but has not moved. If that time is excessive, the
AutoParkTimer server automatically sends the Pioneer Arm to its HOME position and removes power
to its servos. This guards against forgetful neglect.
AutoParkTimer is set from a parameter stored in your robot controller’s FLASH and altered through
the FLASH configuration utility. That timer default also can be disabled, lengthened, or shortened
with an arm-related client command. It gets reset every time your client software sends an arm-
control command through the arm’s servers, too.
Gripper Release Timer
The Pioneer Arm’s gripper servo can be subjected to overheating and stress while grasping an object
and holding it for excessive periods of time. Accordingly, like the automatic shutdown timer, the arm
servers support a special watchdog that automatically opens the gripper to its default HOME position
after it has been closed for a FLASH-parameter set (GripperParkTimer) period of time. A special
client command lets you reset the gripper timer, thereby overriding its immediate effects, as needed8,
although we recommend that you don’t grasp objects for longer than five minutes at a time, with
healthy rest periods in between.
CAREFUL!
Unless carefully managed by your software, the Pioneer Arm gripper timer may act
to drop an object prematurely.
Like AutoParkTimer, the gripper’s watchdog timer GripperParkTimer is a parameter stored in your
robot controller’s FLASH and modified with the FLASH configuration utility. The timer defaults to five
minutes and can be disabled. The timer gets reset every time your software opens the gripper to or
near its HOME position.
Warm Reset
Another Pioneer Arm-server watchdog keeps track of the connection between your robot’s controller
and the arm’s controller. This is most important for when the connection between the arm’s
controller and the arm servers is not enabled while establishing a client-server connection, or is lost
during a client-server session. In these rare circumstances, the servers assume that the arm is
disabled and not in its HOME position, and thereby goes into an arm-disabled state that requires a
special protocol for recovery. The protocol for recovery from a communications failure is either a cold-
reset of the robot’s controller or through the Warm Reset protocol of commands from a connected
client. Of course, take the latter approach if your client software already is connected and controlling
the robot. In all cases, be sure to put the Pioneer Arm into its HOME position before resetting the
system.
8Holding some nearly closed position, but not grasping an object, for example.
9

Software and Programming
Software and Programming
Chapter 3
The Pioneer Arm’s controller is attached to and controlled through an AUX serial port on your robot’s
controller. The robot controller, on the other hand, is connected with your robotics programs through
its HOST serial port. This means that your command and control client programs communicate with
your Pioneer Arm through the Pioneer controller, not directly with the Pioneer Arm’s controller.
Generic versus Server Programming
We connect the Pioneer Arm through the robot’s controller for several reasons: It means that you
need only a single communication channel for all client-server communications with your robot and its
accessories, thereby obviating the need for additional wireless modems or an expensive onboard PC
with multiple serial ports. Perhaps more importantly, we’ve included special servers in your robot
controller’s embedded software that provide control features and watchdogs not available with the
Pioneer Arm’s generic control software and not easily performed from a standard PC.
Even so, Pioneer’s controller servers also support pass-through servers that transfer serial
communications directly to and from the HOST and AUX serial ports, so that you may control your
Pioneer Arm with its generic command set, if you prefer.
Generic Controls
The Pioneer Arm’s generic controller responds to a simple set of commands that enable/disable
power to the servos and position the servo-driven joints. It also lets you query the controller software
version number and accessory digital I/O.
However, the Pioneer Arm’s generic controller has no provision for controlling joint speeds. The servo
motors adjust to their new position as fast as they can, leading to some pretty wild swings unless you
are careful. Nor, with the generic commands, can you query for the current position of a joint.
Your robot’s Pioneer Arm support servers, on the other hand, give you control over joint speeds and
maintain current position information, as well as a variety of other advanced and convenient features.
Which is why we recommend that you program to the Pioneer Arm servers and not to the arm’s generic
command set.
Generic Command Syntax
The Pioneer Arm’s generic control protocols consist of a header byte (255; 0xFF) followed by a
command byte and, sometimes, one command parameter.
The most significant bit (b7) of the command byte determines the mode—set the bit for query mode;
clear it for servo-positioning or digital output port commands. The next three most significant bits of
the command byte (b4-6) select the board number; always 0 for the Pioneer Arm. The remaining bits
of the command byte depend on the command mode.
Generic Commands
The Pioneer Arm’s generic commands let you enable/disable power to the servos and query for the
controller’s software version number and analog/digital port states. The native Arm controller
supports three digital control bits and two analog input channels. Digital channel 0 is connected to
and controls power to the Pioneer Arm’s servo motors. Channel 1 is connected to the status LED
inside the Arm controller box.
You may use the Pioneer Arm controller’s generic servo-positioning command to move a joint. The
command consists of three bytes: The header (255; 0xFF), a servo-selector byte, and the position
value byte. The servo-selector byte’s most significant bit (b7) always is OFF (0) to distinguish servo-
positioning commands from query commands. Its remaining bits (b0-6) select the servo number, for a
total of up to eight joints. Only joints one—the base swivel—through six—the gripper—are active with
the Pioneer Arm.
10
The servo-positioning byte allows up to 255 different servo positions, although in practice the range of
positions for any individual joint and depending on the individual arm varies to roughly 200 positions

MobileRobots Inc.
around values 25-235. Our robot servers let you set realistic position boundaries (MIN and MAX) and
CENTER offsets, so that your client-side code is portable from arm to arm. See following sections for
details.
Table 1. Pioneer Arm generic commands
CONTROL MODE
COMMAND BYTES
DESCRIPTION BOARD RESPONSE
255, 12, 1 Servo Power ON None
255, 12, 0 Servo Power OFF None
255, 128 Request version
number
ASCII-encoded version number,
followed by CR, LF9
255, 133 Read digital port
states
0-7 corresponding to ports 0,
1 and 2, followed by CR, LF
255, s, p Set servo joint s=0-7
to position p=0-255
None
For example, using the generic command to turn the Pioneer Arm fully clockwise around its base
(servo #1), you may send the generic command byte sequence:
255, 1, 255
Similarly, use a three byte command to power the Pioneer Arm servos: The header (255; 0xFF),
command byte 12 (0x0C), followed by a byte value of one to enable, or zero to disable servo power.
Generic Command Communications
The Pioneer Arm’s controller is attached to the AUX serial port on your C166, to either the AUX1 or
AUX2 serial port on your H8S-, or to either the AUX1, AUX2, or AUX3 serial port on your SH2-based
Pioneer controller.10 Use the client TTY2 command #42 to send generic commands from your client
software to the Pioneer Arm controller through AUX1; command #66 (TTY3) for AUX2; or command
#60 (TTY4) for AUX3. Include the Pioneer Arm’s generic command as the integer or string argument.
To retrieve responses from the Pioneer Arm controller using generic commands, use the respective
GETAUX commands (#43, #67, #61 for AUX1-3) and corresponding SERAUXpac (types 176, 184, and
200, respectively) server information packet.
Command and packet details are in your robot’s Operations Manual. MobileRobots’ ARIA client-
development environment supports these functions, too.
Pioneer Controller Arm Servers
Your robot’s controller has software with advanced control functions for safe and convenient operation
of the Pioneer Arm. These include commands to enable and disable power to the arm’s servos, to
move the arm to a new position—joint-by-joint and each at a controllable speed—and to query for
current arm positions and status. The servers also include safety watchdogs and which act to
minimize power consumption as well as help protect your Pioneer Arm and surroundings from
damage.
Client Commands
P2OS, AROS, and ARCOS all support identical servers for control of the Pioneer Arm. Commands
originate in your client software and thereby require that you establish a client-server connection
between your PC and the robot’s controller. After connecting, your client software must tell the servers
to power the Pioneer Arm’s servos before you can send position commands. Note that the arm always
starts a client-server connection in its HOME position and automatically returns to that position when
servo power is set to OFF, including at the termination (CLOSE) of a client-server connection session.
9Carriage return (13; 0x0D) and line-feed (10; 0x0A) characters.
11
10 Depends on physical attachment and ArmPort setting in FLASH. See following chapters for details.

Software and Programming
Table 2. Pioneer Arm client-command set
CLIENT
COMMAND
COMMAND
NUMBER
VALUE(S) DESCRIPTION
INFO 70 none Request an ARMINFOpac server-information packet
STATUS 71 0, 1 or 2 Request one or a continuous stream of ARMpac
information packets; 0 stops continuous
INIT 72 none Warm-reset the Pioneer Arm
CHECK 73 none Has Arm servers check to make sure it’s still
responding to commands; reflects in status byte of
ARMpac.
POWER 74 0 or 1 Switches power off (0) or on (1) to all the Arm
servos
HOME 75 1-6 or >6 Sends all (>6) or specified joint (1-6) to the
HOME position
PARK 76 none Sends all joints to their HOME positions and shuts
power off.
POS 77 two
bytes:
1-6, 0-
255
Sends joint (1st byte) to the position specified
in the 2nd byte, subject to end-limits specified
in FLASH parameters
SPEED 78 two
bytes:
1-6, 1-
127
Delay in milliseconds (2nd byte) between
incremental steps to control the speed and motion
of the joint (1st byte)
STOP 79 1-6 or
255
Stop the specified (1-6) or all (255) moving
joints
AUTOPARK 80 0-65535 Disable the autopark watchdog (0) or reset it to
some time in seconds other than default
AutoParkTimer in FLASH
GRIPPARK 81 0-65535 Disable the gripper watchdog (0) or reset it to
some time in seconds other than the default
GripperParkTimer
Once connected, you may query for status, current servo positions, and other salient information as
included in special arm server-information packets, as well as modify joint speeds. But the Pioneer
Arm will not move nor will the servers update joint positions unless your robot’s controller verifiably
has communication with the arm’s controller and the arm’s servo power is enabled.
There is a special warm-reset protocol your client must perform in the case that the Pioneer Arm
controller is not in contact with the robot’s controller when your client software requests to enable
servo power, or in the case that communication between them is lost during an active session.
Your client software must package arm commands into a special communication packet, and retrieve
and decode the Pioneer Arm-related server-information packet (SIP), as described in your robot’s
Operations Manual and supported in part by various MobileRobots development software.
INFO and ARMINFOpac
The robot’s arm server software maintain detailed information about each servo-driven joint, as well
as connection and power status. Your client software may request that detailed information with the
INFO client command #70, which prompts your robot controller to respond with an ARMINFOpac SIP.
See your Operations Manual for details about SIPs and guidelines on how to write client-side packet
decoders. Arm-related SIP decoders come with the provided ARIA software.
POWER
After establishing a client-server connection, you must send the client command #74 with argument
value of one to have power enabled to the Pioneer Arm’s servos in order to move its joints to positions
other than HOME.
If you subsequently tell the servers to disable power to your arm’s servos (command #74,0), or if your
client disconnects when the servos are enabled, the arm automatically returns to its HOME position and
disables servo power.
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MobileRobots Inc.
Table 3. ARMINFOpac server information packet contents
BYTE VALUE(S) DESCRIPTION
-2 0xFAFB Header signals start of packet
0 n+53 Number of data bytes, including checksum
1 161 ARMINFOpac server information packet ID
2 thru n string NULL-terminated string containing the Pioneer Arm’s version
number response, or “No arm” if not connected.
n+1 0-7 Number of Pioneer Arm joints; default is six; 0 if no Arm.
n+2 0-127 Servo #1’s speed setting.
n+3 0-255 Servo #1’s home position setting.
n+4 0-127 Servo #1’s minimum position value.
n+5 ~127 Servo #1’s center position value.
n+6 127-255 Servo #1’s maximum position value.
n+7 1-255 Servo #1’s ticks per 90 degree rotation value.
n+8 to n+50 … Servo #’s 2-6 speed, home, minimum, center, maximum, and
ticks/90deg settings.
n+51, 52 xx Data checksum
STATUS and ARMpac
The ARMpac SIP provides current Pioneer Arm servo position information as well as arm status. Get
one or a continuous stream (one per standard SIP cycle) of ARMpac SIPs with the STATUS command.
Table 4. ARMpac contents
BYTE VALUE(S) DESCRIPTION
-2 0xFAFB Header
0 11 Data byte count
1 160 ARMpac server information packet ID
2 bit-
endcoded
status
Bit-encoded servo power (b0) and connection (b1) status;
respective bit is set (1) if servo power enabled or a connection
established between Pioneer Arm controller and the robot’s
microcontroller.
3 bit-
encoded
status
Bit-encoded motion status for each servo-driven joint; bit set (1)
if respective joint in motion. Note that only bits 1-6 are active,
corresponding to the current Pioneer Arm’s six servo motors and
joints.
4-9 0-255 ea Servos 1-6 current positions.
10, 11 xx Data checksum
If, in the case that the robot’s controller cannot communicate with the arm’s controller, or if it loses
communication while servo power is enabled, the arm servers automatically revert to the HOME
positions with servo power OFF and will not allow restoration of servo power until reset. See INIT and
Warm Reset Protocols below.
SPEED and POS
The Pioneer Arm servers move a joint from one position to another in individual steps, rather than
effect an uncontrolled jump from one position to another as happens with the generic arm commands.
And the arm servers control each joint’s rotational speed by waiting a particular period of time
13

Software and Programming
between each step for much smoother operation.
Accordingly, to move joint #1 from position 100 to position 200, for example, the robot’s controller
software sends a sequence of 100 individual position commands to the Pioneer Arm controller, each
incremented by one position value and separated by a SPEED number of milliseconds until the joint
reaches its destination.
You may set individual joint speeds on-the-fly with the SPEED command #78 or set their start-up
defaults through FLASH parameters (see next chapter); 1-127 milliseconds delay each. Speeds may
be set at any time, even when the arm is not powered, and persist through servo-power and client
connection/disconnection cycles. Their current values are reflected in the ARMINFOpac.
When powered, control the Pioneer Arm’s servo positions with the POS command #77. Servos vary.
Each joint for your particular arm is characterized by maximum and minimum position values which
limit its range despite the value you may command, as well as a center position. Limiting values for
each and every joint are reflected in the ARMINFOpac, and may be updated in FLASH (see next
chapter). Individual servo positions are reflected in the ARMpac server information packet (see
above).
SPEED Limits
Joint speeds have limits. Generic arm-position commands take two bytes each. Serial communication
with the Pioneer Arm controller is 9600 baud, which is about 1 byte per millisecond. Hence, an
individual joint may move at the maximal speed at about one new position every two milliseconds,
even though the server attempts to update each joint every millisecond.
The delays are cumulative, too. Move two joints at a time, and the maximal update rate, due to serial
communication delays, is every four milliseconds. And so on.
Fortunately, the worst case—all six joints moving at once and requiring simultaneous position
updates—is rare, for which a complete update cycle takes 2 x 6 = 12 milliseconds. As it happens, the
larger, heavier joints move best at slower speeds, and speed-controlling delay times of 15
milliseconds and above are smoothest and plenty fast for most manipulation applications.
HOME and PARK
As described earlier, HOME is a safe and stable position for when the Pioneer Arm servo motors come
to rest. When switching servo power, the HOME position minimizes the drop as the arm goes limp
when powered OFF, as well as the snap-to-position jumps characteristic of servo motors as each joint
seeks its position when powered ON. Indeed, your robot controller’s arm servers always presume that
the Pioneer Arm is stored in its HOME position except when its servo motors power is ON.
Use the HOME command #75 to send one (servo number 1-6 as command parameter) or all (command
parameter >6) of your Pioneer Arm joints to their HOME, default positions.
Use the PARK command #76 to send all the joints to their HOME positions and shut power OFF to the
arm. The HOME and PARK commands are ignored if servo power is OFF.
INIT, CHECK, and Warm Reset Protocol
Upon Main Power start up or controller reset, the Pioneer Arm servers automatically initialize the arm
controller, setting the arm joints to their default HOME positions and their speeds to the defaults stored
in FLASH. It does not apply power to the arm’s servos.
Instead, initialization includes removing power from the arm’s servo motors. Please be careful to
recognize the implications: Upon reset, your robot controller’s arm servers cannot know the positions
of arm joints, and therefore presume, upon initialization, that they are at or near their HOME positions.
When reset, the controller’s arm servers cannot and will not drive the Pioneer Arm servos to their HOME
positions, as they may do under other circumstances.
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MobileRobots Inc.
CAREFUL!
Put the Pioneer Arm into its HOME position
BEFORE
resetting the microcontroller.
Your Pioneer Arm may flop dangerously if it is not in its HOME position, and
consequently flail erratically to that position when its servos get powered. So be
very careful to have the Pioneer Arm in its HOME position before you turn on your
robot’s Main Power or reset the robot’s microcontroller!
The arm servers also monitor the serial connection with the arm’s controller. If the robot’s controller
does not detect the arm, or if it loses contact with the arm’s controller when the arm’s servos are
enabled, your robot’s controller automatically shuts down command and control, and awaits a warm-
reset command from the client to re-establish command and control of the Pioneer Arm through the
arm servers.
In the meantime, you should manually restore the Pioneer Arm to its HOME position.
For your client to recover command and control of the Pioneer Arm while remaining connected after
the communication failure, you must follow the warm-reset protocol:
1. Request status (STAT) or CHECK and wait for restoration of communication (bit 1 of the status
byte)
2. Issue the INIT command
3. Use STAT and INFO SIP requests to reinitialize any client-side variables that my be tracking
joint positions
4. Issue the POWER command to power the Arm servos
5. Resume operation
Note that while the joint positions are reset to HOME; the latest joint speed settings persist.
ARIA and ArAKin Arm Support
15
The classes and methods for ARIA-based client operation of the Pioneer Arm and the companion
ArAKin and AKIN forward and inverse kinematics libraries are documented extensively in their
respective ARIA directories. ARIA is the preferred foundation software for client-server

Software and Programming
communications and control of MOBILEROBOTS platforms and accessories. It’s free, published under
the GNU General Public License, and comes not only with source code, but with many examples of
robot and accessory control client software.
ArAKin libraries depend on the licensed AKin forward/inverse kinematics libraries. New Pioneer Arm
owners automatically receive a license. Legacy owners may purchase a license from
[email protected].
ArP2ArmSimple, ArAKinDemo and ArAKinExample
All current ARIA distributions contain sources for individual joint- and general Pioneer Arm
maintenance client activities, as well as the ArAKin kinematics libraries. Install the software into your
ARIA directory, typically in C:\Program Files\MobileRobots\Aria or /usr/local/Aria. Be sure
to use matching ARIA and ArAKin versions.
In the generic Aria/examples subdirectory, find and create the ArP2ArmSimple program which
shows you how to connect and operate the individual arm joints, as well as monitor arm states and
positions through ARIA. In the nearby Aria/ArAKin/examples subdirectory, build and execute the
ARIA-integrated, AKin-based kinematics demonstrations, ArAKinDemo and ArAKinExample.11
These simple demonstration programs just exercise the Pioneer Arm, but modify their source code at
will to incorporate your own actions with other Pioneer robotics functions.
11 Windows executables get put into the Aria\bin directory.
16