Robotics tutorial: More diversity, functionality

Robotics are adapted to and integrated with an increasing diversity of applications. Understanding types of robots and their functions can help end users, system integrators, and original equipment manufacturers know how to safely and efficiently apply technologies that save humans from tasks that are both mundane and dangerous.
By Mark T. Hoske, Control Engineering October 1, 2008
Cartesian robots are ideal for precise operations like electronics assembly, inspection, and dispensing. Source: Bosch Rexroth
Above: Cartesian robots are ideal for precise operations like electronics assembly, inspection, and dispensing. Source: Bosch Rexroth
Below: Even among cartesian robots, there’s diversity, as this Hercules Gantry X-Y robot shows. Source: Rockwell Automation
Even among cartesian robots, there

Robotics are adapted to and integrated with an increasing diversity of applications. Understanding types of robots and their functions can help end users, system integrators, and original equipment manufacturers know how to safely and efficiently apply technologies that save humans from tasks that are both mundane and dangerous.

In industries from automotive to packaging, the use of robots is increasing steadily and impressively, says Dan Throne, sales and marketing manager, Bosch Rexroth Corp.– Electric Drives and Controls.

North American robotics orders rose 24% in 2007 over 2006, he says, citing Robotics Industries Association (RIA). Today’s robots offer repeatability, speed, accuracy, ability to operate in harsh environments, reduced total footprint, less scrap, and more flexibility than prior generations.

“That last attribute—flexibility—probably gets the most attention. Flexibility means that countless robotic solutions can be configured from a few basic types of robots,” Throne says. These include:

  • SCARA (selective compliant articulated robot arm) robots, with arms rigid in the Z-axis and moveable in the X-Y axes, are ideal for assembly operations like inserting pins in holes. SCARA robots can be faster than Cartesian robots and have a small footprint, but are often more costly.

  • Parallelogram robots use 3 parallelograms and rotating levers operated by servo motors or linear actuators. They’re well suited to pick-and-place operations.

  • Delta robots are a form of parallelogram robots used for top loading and infeeds, and can execute up to 150 picks per minute—perfect for packaging, pharmaceutical, assembly, and clean-room applications.

  • Cartesian robots have linear axes of control, and can be configured for “brawn” operations (transporting auto body parts) or “brains” operations like creating precise designs on a surface.

  • Articulated robots have a rotating trunk, shoulder, bicep, forearm and wrist. They are well suited for placing small parts accurately as well as packing and palletizing.

Availability of standardized programming, make robots easier to control, configure, and reconfigure. Unlike the expensive and proprietary products of the past, Throne says, today’s motion control and PLC products allow plants to run robotics using standard programming languages such as IEC 61131-3. Standardized controls with user-friendly software setup wizards require no downtime for specialized operator or programmer training.

When choosing a robot type, look at payload, space constraints and application uses, among other considerations, says John Good, director of marketing, linear motion solutions business, Rockwell Automation.

“Increased demand for applications that require dynamic performance, high reliability, greater accuracy and improved repeatability has pushed adoption of direct drive technology,” which can improve performance over “belts, ball screws, rack and pinion, and feature improved reliability, accuracy and repeatability.”

ONLINE extra

Controls add to robotic flexibility, application diversity; photo gallery

Original equipment manufacturers are starting to run robotics with off-the-shelf controls. Even large robot manufacturers are adopting the use of embedded nonproprietary software. Tutorial, robotic photo gallery, useful links follow.

www.controleng.com/article/ca6597271.html

Author Information
Mark T. Hoske, editor in chief, can be reached at mhoske@reedbusinss.com .