User`s guide

The robot tool moves at the constant speed of 0.75 inch per second through each location
defined in the array path[]. (One way to create the path array is to use the V+ TEACH
command to move the robot along the desired path and to press repeatedly the RECORD
button on the manual control pendant.)
In the next example, the robot tool is to be moved along a circular arc. However, the path is
not prerecorded-it is described mathematically, based on the radius and center of the arc to
be followed.
The program segment below assumes that a real variable radius has already been assigned
the radius of the desired arc, and x.center and y.center have been assigned the respective
coordinates of the center of curvature. The variables start and last are assumed to have been
defined to describe the portion of the circle to be traced. Finally, the variable angle.step is
assumed to have been defined to specify the (angular) increment to be traversed in each
incremental motion. (Because the DURATION instruction is used, the program moves the
robot tool angle.step degrees around the arc every 0.5 second.)
When this program segment is executed, the X and Y coordinates of points on the arc are
repeatedly computed. They are then used to create a transformation that defines the
destination for the next robot motion segment.
DURATION 0.5 ALWAYS
FOR angle = start TO last STEP angle.step
x = radius*COS(angle)+x.center
y = radius*SIN(angle)+y.center
MOVE TRANS(x, y, 0, 0, 180, 0)
END
Timing Considerations
Because of the computation time required by V+ to perform the transitions between motion
segments, there is a limit on how closely spaced commanded locations can be. When
locations are too close together, there is not enough time for V+ to compute and perform the
transition from one motion to the next, and there will be a break in the continuous-path
motion. This means that the robot stops momentarily at intermediate locations.
The minimum spacing that can be used between locations before this effect occurs is
determined by the time required to complete the motion from one location to the next.
Straight-line motions can be used if the motion segments take more than about 32
milliseconds each. Joint-interpolated motions can be used with motion segments as short as
about 16 milliseconds each.
NOTE:The standard trajectory generation frequency is 62.5 Hz. With an optional software
license, trajectory frequencies of 125 Hz, 250 Hz, and 500 Hz are possible.
The minimum motion times for joint and straight-line motions must be greater than or
equal to the configured trajectory cycle time. As a convenience, if they are set to be less
Motion Control Instructions
V+Language User's Guide, v17.0
Page 184