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The idea of open controllers for robots got a boost recently as Ford Motor Co. made an investment in Robotic Workspace Technologies (RWT) Inc. According to Ford's Technology Venture Fund manager Chris Johnson, the automaker teamed up with Fort Meyers, Fla. based RWT as a way of reducing operational costs in its factories.

Robot-arm kinematics on the RWT controller are programmed into controller cards from Delta Tau Data Systems Inc. These board-level controllers carry fast digital signal processors for calculating forward and inverse kinematics between world and joint coordinates, as well as real-time dynamic checking of joint limits (position, velocity, and acceleration) for moves programmed in world coordinates. This helps eliminate wrist snap problems that can crop up when passing near singularities. www.deltatau.com

RWT produces controllers that can retrofit onto older articulated robot arms, sometimes boosting performance beyond what the arm was capable of when new. RWT uses controller electronics that are PC-based and off-the-shelf. To this the firm adds software it has written to handle the kinematics for robot arms from Fanuc, Kawasaki, ABB, and others. It also adds a programming language used to devise moves. The language is the same no matter whose arm the controller is paired with.

The resulting open architecture platforms, says RWT, are less expensive than upgrading the proprietary controls for the robots. And they attack a problem: Robot controllers become obsolete every seven years on average, and it is not uncommon for new controllers to feature a new programming language. Existing control programs often cannot be used on the new systems. Robot OEMs eventually stop supporting the older models, and spare circuit boards become hard to find.

There are no such difficulties with an open platform, says RWT. The value is in the software, not the electronics which can be upgraded easily. In fact, "We've had conversations with Kawasaki, ABB, and others and offered to give them the controller for a small