Controller gives robots added 'smarts.' (remote control of robotics) (Technology News)(Injection Molding)

A wireless controller that fits in the palm of one hand will soon make Conair Harmo sprue pickers more flexible, even allowing them to work as parts-removal robots. Developed by Harmo Co. Ltd. of Japan, in conjunction with Advanced Control Electronics (ACE) of Elgin, Ill., the Laser Command control system will let molders set a range of robot movements and speeds from the unit's keypad without custom programming or rewiring.

Conair Martin of Agawam, Mass., unveiled the remote-control system for its EX series of sprue pickers at the Cleveland Plastics Fair last month, though it will not be commercially available until later this year. Conair v.p. Edward Skiba says the controller addresses a growing need for "flexibility and ease of making set-up changes." As a retrofit, the unit can upgrade existing EX models, which work with presses up to 500 tons. The handheld control "pendant" has a keypad and LCD display.

The controller communicates with the EX sprue pickers in two ways--by remote and by wire. In the remote mode, the unit uses an infrared signal for adjustments that require one-way communication, such as changing the robot's timer settings or its motion sequence. Identification codes have been built into the controllers so that each one works only with its intended sprue picker, according to ACE v.p. Kevin Bertness. A single controller can also work with more than one picker.

The same sorts of speed and motion changes carried out in the remote mode can also be made via a wire hookup. But the latter also permits two-way communications for checking the status of the robot settings or performing diagnostics. Bertness notes that the control system "optically isolates" the wire's electrical signal at both the pendant and the robot ends to eliminate electrical noise problems while avoiding the cost of fiber optics.

NOT JUST FOR SPRUES

Contrasting the new control system with conventional ones, ACE president Michael Waters notes that earlier systems could not change functions without some rewiring or reprogramming. The new controller departs from this hard-wired approach by letting molders change all the robot's operating parameters with the keypad.

For example, a single button rotates the robot's "home position" from vertical to horizontal. Waters points out the importance of that feature when adding an unscrewing hydraulic rack or making other sorts of tooling changes. Another button allows users to choose between "U" or "L" arm motion. The controller can similarly control four types of gripper setups, as well as different subarm assemblies and speeds.

Other features simplify setups, according to Skiba. Manual operations instruct the robot arm to travel a step forward or backward, making it easier to adapt the robot for different applications. And diagnostics display press conditions and arm positions on the screen.

"This high degree of control flexibility allows processors to more easily transform a Harmo sprue picker into a parts-removal robot," Skiba claims. "It can even place parts and sprues in different locations." Because the controller lets the EX models do more than a sprue picker's normal job, it has been designed to meet the SPI's most recent robot interface standards, according to Bertness. He notes that the picker's flexibility also springs from its information-storage abilities. In place of dedicated programs, the unit's software allows users to store robot settings and time values for up to 15 different tasks. "We've virtually eliminated the need for custom programming."

But just in case, the controller has provisions for applications not explicitly covered by ACE's software. Using a personal computer and an English-based programming language, molders can create their own programs. All the stored information resides within the handheld pendant. That way, a molder could transfer a group of settings or his own custom programs between machines when switching molds. "This feature eliminates setup delays from machine to machine," Waters says, noting that most robots are keyed to an individual press. For Skiba, the upshot of this information-transfer ability is "process consistency between one press and another."

ROOM TO GROW

The controller was built with expansion in mind, Waters explains. So the system has features, like extra inputs and outputs, which outstrip the needs of the current EX series. It can, for instance, control more motors than the sprue pickers currently use. Skiba adds that capacity not being used now "will accommodate some upcoming mechanical advances." He reveals only one example for now--automatic motorized stops for positioning the robot arm in front of the mold face. Adjustable from the keypad, the stops would eliminate the need to climb above the sprue picker to tinker with arm positioning. (CIRCLE 17)