Using a novel method of integrating video technology and familiar control devices, a research team from Georgia Tech and the Georgia Tech Research Institute (GTRI) is developing a technique to simplify remote control of robotic devices.
The aim is to enhance a human operator’s ability to perform precise tasks using a multi-jointed robotic device such as an articulated mechanical arm. The new approach has been shown to be easier and faster than older methods, especially when the robot is controlled by an operator who is watching it in a video monitor.
Known as Uncalibrated Visual Servoing for Intuitive Human Guidance of Robots, the new method uses a special implementation of an existing vision-guided control method called visual servoing (VS). By applying visual-servoing technology in innovative ways, the researchers have constructed a robotic system that responds to human commands more directly and intuitively than older techniques.
To simplify user control, the team turned to visual servoing (a term synonymous with visual activation). Visual servoing has been studied for years as a way to use video cameras to help robots re-orient themselves within a structured environment such as an assembly line.
The new technique takes advantage of both calibrated and uncalibrated techniques. A calibrated 3-D “time of flight” camera is mounted on the robot – typically at the end of a robotic arm, in a gripping device called an end-effector. This approach is sometimes called an eye-in-hand system, because of the camera’s location in the robot’s “hand.”
The camera utilizes an active sensor that detects depth data, allowing it to send back 3-D coordinates that pinpoint the end-effector’s spatial location. At the same time, the eye-in-hand camera also supplies a standard, uncalibrated 2D grayscale video image to the operator’s monitor. The result is that the operator, without seeing the robot, now has a robot’s-eye view of the target. Watching this image in a monitor, an operator can visually guide the robot using a gamepad, in a manner somewhat reminiscent of a first-person 3-D video game.
