How delta robotics optimize and streamline electronics manufacturing processes
structure lets delta robots quickly accelerate to deliver very short cycle times. Another type of parallel manipulator is the Stewart platform or hexapod; these deliver maximal stiffness, precision, and speed — often to correct for vibrations in real time in precision optics applications. Typically each parallelogram on a delta robot is actuated by a rotary electric motor via linear actuation. (Low-cost delta robots from the Igus Drylin series use a less common linear-drive configuration.) The coupling of parallelograms constrains the end effector to only translational motion. That imparts the same degrees of motion as a three-axis cartesian machine but with a much stiffer and lighter structure. An added advantage of this configuration is that the mass of the drive motors is located in the (typically ceiling-mounted) base, so all the robot’s moving parts are passive lightweight structural elements. Some delta robots have additional rotary axes mounted in series at the end effector to provide four, five, or six-axis motion. Overview of delta robot applications Delta robots are widely used in pick-and-place applications for electronics assembly as well
Figure 3: Shown here is a vision-laden work cell that employs delta robots, SCARA robots, and mobile robots. The delta robot is stainless steel and IP-67 rated. (Image source: KUKA)
as food and pharmaceutical packaging. When a delta robot operates over one or more conveyors or mobile assembly platforms, items are conveyed or otherwise transported into the
robot’s working volume. Then a vision system identifies parts’ exact locations and orientations to guide the robot on where and how to grasp or otherwise operate on the part.
Figure 4: This servomotor-driven delta robot moves to 200 cycles per minute in three degrees of freedom (DOFs) plus a rotational axis. A controller can command these robots’ axes with 2-msec response time to synchronize with conveyors and other tasks. In fact, another delta-robot is the Quattro; it has four instead of three parallelograms connecting the base to the end effector to deliver high stiffness and positioning accuracy at high speeds. (Image source: Omron Automation)
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