X/Y/Z/Theta Device Module
The X/Y/Z/Theta device module file contains one X/Y/Z/Theta device module that may be used to control up to four axes. Because of the flexibility and generality of the X/Y/Z/Theta module, this file is supplied standard with all AdeptMotion systems.
Copying the Device Module File to a Boot Disk
In order to control a mechanism, the device module file must be installed in your system file. Refer to Chapter 6 for details on using CONFIG_C to install this device module file in your system file.
If you have a hard drive, the device files will normally be already stored in the c:\system\ subdirectory. Answer "XYZ" to the prompt asking you to enter the name of the device module you want to transfer to your system file.
X/Y/Z/Theta Device Module Description
An X/Y/Z/Theta device module can control up to a four degree-of-freedom mechanism that consists of three orthogonal linear axes followed by a revolute axis. Typical examples of such mechanisms are linear axes, rotational axes, X/Y tables, and gantry robots.
Module Specifications
Device Module Identification Number: 8
This number is displayed along with the robot serial and model number after the system boots up and whenever the ID monitor command is issued.
Default Start-up Message: X/Y/Z/Theta Robot Control Module
The start-up message is displayed just after the system boots up.
Default Joint Configuration:
Joint
Axis
Board/Channel
1
1 (X)
1/1
2
2 (Y)
1/2
3
3 (Z)
1/3
4
4 (Theta)
1/4
With multiple robots, it will be necessary to correct the joint configuration from the SPEC program to avoid conflicts.
Robot Option Word
This module does not use any bits of the robot option word. You should leave its value at 0.
Axis Configuration
Although the system is designed to support up to four axes, any combination of these axes can be selectively disabled to provide control for a lesser degree-of-freedom device. The directions of motion of the axes as described below will determine the setting of the encoder sign specified in the SPEC utility program (see Figure B-1). The four axes of motion are defined as follows:
Axis 1 is a linear axis that moves in the world X direction. A POSITIVE displacement of the joint moves the robot in the POSITIVE world X direction.
Axis 2 is a linear axis that moves in the world Y direction. A POSITIVE displacement of the joint moves the robot in the POSITIVE world Y direction.
Axis 3 is a linear axis that moves in the world Z direction. A POSITIVE displacement of the joint moves the robot in the NEGATIVE world Z direction.
Axis 4 is a revolute axis (theta) about the world Z direction. A POSITIVE rotation of the joint turns the robot's end effector in a NEGATIVE direction relative to the world Z axis. The axis of rotation of joint 4 defines the nominal Z axis of the robot's tool frame of reference. That is, if a NULL tool is defined, the Z axis of the tool frame will be colinear with the axis of rotation of joint 4 and will be pointed in the direction of the negative world Z axis.
As with all other robot modules, the standard V+ BASE and TOOL transformations can be used in combination with the geometric model to specify and compute the end point of the robot relative to the world coordinate frame
Variations in Axis Configuration
This module can be configured to control any combination of the four axes ranging from any single joint on up to all four axes.
Geometric Dimensional Constants
There are no dimensional constants that can be specified for this device other than the tool offset distance. By default, the world Z height is 0 when the Z-axis joint position is 0, and as the Z-axis extends in the positive direction, the world Z-height becomes negative. The tool offset distance can be used to change the default world Z height of the robot.
The only geometric constraints of importance are that the base linear axes must be mutually perpendicular. It is not important whether the mechanical drive axes that implement the mechanism are intersecting or offset from one another. In fact, the origin of the world coordinate system can be arbitrarily defined to be any point relative to the axes drives so long as it is consistently defined from one working session to the next.
Cartesian Motion
During program generated straight line motions, the first Cartesian rotation speed controls the rate at which joint 4 rotates and should be set to be consistent with the joint interpolated speed for joint 4. If the Theta axis is not configured, the first Cartesian rotation speed should be set to zero. The second and third Cartesian rotation angles are not utilized and their speeds should likewise be set to zero.
Because the joint axes align with the Cartesian axes, the specification parameters for joint speeds and accelerations should be consistent with those for Cartesian speeds and accelerations for both pendant and program control. For example, the Cartesian translation speed and acceleration will normally be close to the average of the linear axes' speeds and accelerations.
Coupling Between Robot Joints and Motors
This module does not allow multiple motors to couple into the motion of any single axis.
Robot Configuration Control Instructions
The following robot configuration-control program instructions do not have any effect upon the operation of mechanisms controlled by this module:
ABOVE, BELOW, FLIP, NOFLIP, LEFTY, RIGHTY
Additional Restrictions
None
Last modified on: 02/13/2007
Copyright © 2007 by Adept Technology, Inc.
All rights reserved.
