Wednesday, August 17, 2011

Teleoperating a Denso Robot

A year ago I wrote about our open architecture 6 Degree of Freedom (DOF) Denso robot. Coupled with Quanser's QUARC control software, it offers researchers and students an extremely user-friendly programming environment. That means they can use the industrial grade robot in teaching and research labs, without having to spend their time typing endless lines of low level code to move a robotic arm. No wonder the robot workstation has become increasingly popular with our academic clients and research partners.

As an example, consider the Health Research Innovation Centre at University of Calgary. The setup at the Centre, which includes our Denso Open Architecture Robot Workstation and a high definition haptic device HD^2 is used for research and development of the neuroArm, a robotic arm used for telesurgery.

The video below demonstrates the Denso robot being teleoperated by the HD^2 high definition haptic device. Communication is conducted over shared memory for optimized bilateral teleoperation performance. It can be easily switched to another protocol over the Internet using QUARC blocksets.

The motion of the operator’s hand is captured by the haptic device at a high resolution and speed. This motion then drives the end-effector of the Denso robot over 6 degrees of freedom, i.e., translational x, y, z, and rotational roll, pitch and yaw. The measured forces and torques at the tip of the robot are applied back to the operator through the haptic device.

The monitor, visible at the top left corner of the video, demonstrates an OpenGL visualization of the Denso robot in real-time where some virtual objects are added to the graphics of the Denso robot. These virtual objects represent the virtual fixtures that act on the tip of the robot. When the robot end-effector goes into contact with these virtual objects, a feedback force is calculated based on the simulated dynamics of the objects. The force is then applied back to the user through the haptic device. As a result, the operator will be repelled from certain regions in the robot workspace. One can think of it as a means of guiding the surgeon out of some delicate regions of a brain during the surgery.

Overall, in this setup, the Denso robot, a 7 DOF haptic device, the simulation, and the force sensor are all interfaced to each other on a single PC through QUARC control software. Along with all this is a 1 DOF actuator at the end-effector of the robot, which is controlled through a QUARC serial communication blockset.

To sum up, the 6 DOF Denso Open Architecture Robot Workstation from Quanser is a state of the art, cost-effective solution for all those interested in teaching robotics or doing research in this field. No surprise that its popularity is growing by the day.

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