Joint-Interpolated Motion vs. Straight-Line Motion Making smooth transitions between motion segments without stopping the robot motion is called con- tinuous-path operation. If desired, the robot can be operated in a non-continuous-path mode, which is also known as "breaking continuous path" operation. When continuous-path operation is not used, the robot decelerates and stops at the end of each motion segment before beginning to move to the next location. The stops at intermediate locations are referred to as “breaks” in continuous-path operation.
This method is useful when the robot must be stopped while some operation is performed (for example, closing the grip- per or applying a dot of adhesive). The continuous or non-continuous path motion is set using the Wait Until Motion Done parameter and Motion End parameter in the Pick Motion Parameters or Place Motion Parameters dialogs. To enable continuous-path operation, you must set both parameters as follows: l Wait Until Motion Done = False l Motion End = Blend NOTE: Breaking continuous-path operation affects forward processing (the parallel operation of robot motion and program execution). Program operation is suspended until the robot reaches its des- tination.
Continuous-path transitions can occur between any combination of straight-line and joint-interpolated motions (see “Joint-Interpolated Motion vs. Straight-Line Motion” in the following section). Joint-Interpolated Motion vs. Straight-Line Motion The path a robot takes when moving from one location to another can be either a joint-interpolated motion or a straight-line motion. A joint-interpolated motion moves each joint at a constant speed (except during the acceleration/deceleration phases-see Speed, Acceleration, and Deceleration on page 61). With a rota- tionally-jointed robot, the robot tool tip typically moves along a curved path during a joint-interpolated motion.
Although such motions can be performed at maximum speed, the nature of the path can be undesirable. Straight-line motions ensure that the robot tool tip traces a straight line. That is useful for cutting a straight line, or laying a bead of sealant, or any other situation where a totally predictable path is desired. NOTE: For X, XY, XYZ, or XYZT devices, straight-line motion and joint-interpolated motion result in identical paths, because the (positioning) joints all move in straight lines themselves. The joint-interpolated or straight-line motion is set using the Straight parameter in the Pick Motion Para- meters or Place Motion Parameters dialogs.
Performance Considerations Things that may impact performance in most applications include robot mounting, cell layout, part hand- ling, and programming approaches. Robot Mounting Considerations The mounting surface should be smooth, flat and rigid. Vibration and flexing will degrade performance. Therefore, it is recommended that you carefully follow the robot-mounting procedures described in your robot user's guide. When positioning a robot in the workcell, take advantage of moving multiple joints for ACE User's Guide, 3.6.x 18316-000 Rev A Page 64