RoboCell Background Informational Sheet
A robot can be defined as a computer-controlled machine that is programmed to
move, manipulate objects, and accomplish work while interacting with its
environment.
Some advantages of robots are their ability to perform repetitive tasks quicker,
cheaper, and more accurately than humans.
A robot system is made up of the following elements:
 Manipulator arm
 End effector - the gripper or tool mounted on the end of the arm
 Robot controller – the interface between the robot and computer
 Computer - for programming the robot
In industry robot systems can perform specific tasks by connecting special tools,
called end effectors, to the robot’s arm in place of the gripper. In the activities that
you will complete with the simulation software, the end effector will always be a
gripper.
Tool Center Point
Control over the robot is based on controlling the location, position, and movement
of the tool attached to the robot arm.
In order for the robot controller and the computer to accomplish this task, the
computer/controller needs a point of reference, known as the Tool Center Point
(TCP).
This point will always be located at the very end of the robot gripper.
Cartesian Coordinate System
The Cartesian coordinate system specifies a robot’s TCP position in space.
In a Cartesian coordinate system, each point has a singular and unique value that is
made up of three numbers (known as the point’s coordinates).
The first number represents the distance of the point along the X-axis, the second
the distance of the point along the Y-axis, and the third the distance of the point
along the Z-axis.
The sign of the coordinates (+ or -) indicates its direction along each axis.
© 2013 Project Lead The Way, Inc.
CIM RoboCell Background Informational Sheet – Page 1
In this coordinate system, the coordinates of the origin (where each of the axes
intersect) is (0, 0, 0).
In robot system, the center of the robot base (on the table) is defined as the origin.
Therefore, moving the TCP, when facing the robot:
Up/down is considered movement along the Z-axis.
Right/left is considered movement along the Y-axis.
Away from/toward the robot base is considered movement along the X-axis.
The robot joints are number starting at the waist (#!) moving upward.
NOTE: This is different from accepted practice. Normally moving left/right is
considered the X-axis and away/towards the robot base is the Y-axis.
Pitch and Roll
The positions for the Scorbot robot provide additional information to define the
robot’s TCP to include a pitch and roll angle.
The pitch is a specified rotation about the Y axis.
The roll angle is a specified rotation about the Z axis.
Record and Teach Commands
When programming a robot, you can record or teach positions.
Record Position command is used to record the current TCP position. Use this
command if you manually move the robot to the desired position or if do not know
the accurate coordinates of a position that you wish to use in your program. Once
the robot is at the desired location, hit the Record button. The X-Y-Z coordinates and
pitch and roll angles of the current location will be saved as a robot position.
Teach Position command is used to designate a TCP position by typing the
coordinates (and angles) of the desired TCP position with the keyboard. You would
use this method if you know the accurate coordinates of a position that you wish to
use in your program. Enter the values for the X-Y-Z coordinates and the pitch and
roll angles. Then click on the Teach button.
The Teach Position function is most effectively used for position modification. You
can use it to adjust a known position’s location. Or you can use the coordinates of an
existing position to create a new position whose locations differ slightly from the first.
Modify an existing position by entering position number, click Record then Get
Position. Click Teach to record X, Y, and Z position or Record to record joint
positions.
Test an existing position by entering the position number the click Get Position.
Use the arrow to move by linear or joint to the position.
© 2013 Project Lead The Way, Inc.
CIM RoboCell Background Informational Sheet – Page 2
The Remark Command
It is useful if a programmer can insert notes or comments into a program to provide
assistance in overseeing the operation of the program. It can be confusing to look at
a program and try to determine the intent of the program. This is where the Remark
command is used. With this command you can insert your comments into the
program in a format that the robot will not recognize. The robot will ignore your
statements and will not execute them as a part of the program.
The format for the Remark statement is shown below.
Remark: Your Name
© 2013 Project Lead The Way, Inc.
CIM RoboCell Background Informational Sheet – Page 3