Coordinated motion is a motion control method in which the tool center point (TCP) speed and position of a follower motion group is executed relative to a leader motion group. This method provides constant relative speed between the two motion groups, and provides for path execution by the follower in a moving frame of the leader.
This section contains descriptions of terms that are used in coordinated motion. Become familiar with these terms before you continue with coordinated motion setup, operation, and programming.
Coordinated motion occurs between coordinated motion group pairs, called CD_pairs . CD_pairs consist of a leader motion group and a follower motion group. The leader group can be any kind of positioner, such as a table. The follower group is usually the robot.
The leader group (for example, a positioner) must have FANUC America Corporation motors and be controlled by the robot as a separate motion group. This differs from the conventional positioner installation, which typically uses extended axes or uses the multiple-motion group "NOBOT" configuration.
This new kinematic type is called a Positioner . FANUC America Corporation supports a standard positioner (AMHS500), and a generic type positioner. The positioner can consist of 1-6 axes that can be linear, rotary, or a combination of both. The General Positioner is an extended version of the Positioner. Unlike the Positioner, the axes of a general positioner can be set up at any angle.
A motion group defines a set of motors and axes that are combined to accomplish a motion task. FANUC America Corporation robots are an example of a motion group, typically Group 1. Additional motion groups are defined to control axes on a piece of equipment other than the robot.
The maximum number of groups that can be supported by a controller is eight. Up to four positioner devices can be added as motion groups to the system.
Each additional motion group can have
Up to six motors
Up to three extended axes
Up to four full kinematics devices (robot mechanical units) are supported on one controller
You cannot exceed nine axes per robot motion group; you cannot exceed four axes per non-robot motion group.
Up to four non-robot motion groups can be defined. The maximum number includes extended axes. This includes General Positioner, Basic Positioner, and Independent Axis devices.
One to three extended axes can be added to a motion group. The axes cannot be used independently of the motion group.
Each extended axis adds a position data field (E1, E2, E3) to the motion group data.
The Index axis device is one axes by definition and the Arc Positioner device is a two-axis motion group device. Neither of these can have additional axes installed.
The limitation of a maximum of two Index Devices has been removed
When you use coordinated motion, the "coordination" that is performed is between two motion groups.
The leader group has independent motion during coordinated motions. Typically, the leader group is the positioner.
The follower group executes motion with respect to the leader group. During coordinated jogging, for example, when the leader group is moved, the follower group will maintain the same relative position with respect to the leader. Typically, the follower group is the robot.
There are cases where multiple robot followers will be present in a robot program. If the part paths are identical or mirrored (ie. a motion segment on the first follower robot and the second, etc. are the same length) then all the follower robots will be executing coordinated motion. In practice, there are small path differences between the follower robots, so the follower with the longest segment will dictate the time for the move and will be exactly coordinated with the leader. The other follower robots will execute at a lower speed than the programmed speed.)
Linear refers to the mechanical motion produced when the axis motor is run. Linear motion is straight line motion. This motion occurs for lead screw-type drives and rack and pinion-type drives.
Rotary refers to mechanical motion that rotates about a fixed point when the axis motor is run. Harmonic drives typically have rotary motion output. The typical positioner has a rotary tabletop axis.
The axis offset defines the x, y, and z coordinate difference between the center of rotation of two axes of a multiple axis positioner device. The x, y, and z offsets are with respect to the positioner frame x, y, and z origin. The offsets are calculated automatically when unknown kinematic calibration is performed.
The first axis of a multiple axis positioner will not have an offset. However, subsequent axes will have an offset with respect to the first axis in a positioner group.
The coordinated frame is the frame of the leader group. This frame is created when the leader and follower are calibrated as a coordinated pair (CD_pair). For example, the coordinated frame is the frame that is "connected" to the leader (positioner) table top, which moves when the table moves. The motion of the follower is executed with respect to this moving frame.
The origin of the leader frame is expressed as a position in the robot WORLD frame. It is the transformation from the robot origin to the leader origin.
The leader TCP is a position relative to the leader origin. It is expressed as a position in the leader WORLD frame.
The follower UFRAME has the effect of moving the coordinated frame, when used with coordinated jogging or the program execution of coordinated motion. The UFRAME should be defined relative to the leader WORLD coordinate system, for ease of programming, if UFRAME is to be used in coordinated motion programs.
Changing the UFRAME will shift all of the programmed positions by the same amount for non-coordinated motion programs. It has the effect of shifting the origin of the coordinated frame. When applied to coordinated moves, this provides a convenient way to shift a coordinated motion program, if the relationship between the positioner (leader) and the robot (follower) has been changed. This can occur if the positioner is moved.
The follower UFRAME (user frame) performs the same function as the user frame in non-coordinated motion.
The follower UFrame can be configured as a dynamic uframe. This frame moves with the leader and corresponds to the leader frame at the current leader position. The dynamic uframe is useful when the workpiece is shifted from the original taught position, for workcell cloning, or for transferring programs between the controller and ROBOGUIDE.
Refer to the Leader Frame Setup section of the Coordinated Motion Setup and Operations Manual for more description of the dynamic uframe and setup of the leader frame.
Unless dynamic uframe is used, do not shift UFRAME to compensate for shifted workpieces or programs. Otherwise, motion might not occur as expected relative to the workpiece.
The follower UTOOL is the standard tool frame. This is the same as the tool frame used for the robot in non-coordinated motion. Refer to the appropriate application-specific Setup and Operations Manual for more information.
Use the 6-point method to define UTOOL. Ensure that you have defined the UTOOL correctly prior to CD_pair calibration or programming.
The origin of the leader world frame is based on the positioner. This frame need not have any alignment with the robot world frame. Refer to Section 1.8, " Coordinated Frame " for more information.