Robot-Assisted Drilling on Curved Surfaces with Haptic Guidance under Adaptive Admittance Control
A. Madani, P. Niaz, B. Guler, Y. Aydin, C. Basdogan
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2022)
In this paper, we used a 6-DOF adaptive admittance controller to perform drilling on a curved surface with an unknown surface geometry via a collaborative robot, at custom non-perpendicular drilling angles, with the help of 3D scanning done with a Microsoft Kinect camera. A Microsoft Hololens AR Goggle guided the user throughout the process, increasing task efficiency further. Once target position and surface normal information were extracted via 3D scanning (using the Kinect camera) followed by geometric referencing, they were sent to the robot. The human then guided the robot through the obstacles and convex/concave areas of the curved workpiece towards the target. Once the robot was close enough to the target, a so-called "haptic guidance module" took over, aligning the drill bit tip exactly with the target, at the chosen drilling angle (specified by azimuth and polar angles relative to the workpiece). The admittance controller was locked on the chosen drilling vector, effectively becoming a 1D admittance controller along the drilling angle. The operator then took back control of the robot and drilled through the workpiece by simply pushing the robot forwards. The adaptive controller selected low damping during driving the robot and increased the damping to a safer value when the robot was close enough to the target. Much higher damping was chosen for the final drilling phase to maximize stability and accuracy during the drilling.