Automatic Screw Fastening and Disassembly Process using Active Compliance and Hand-eye System

 Screw fastening and unfastening are essential operations in industrial assembly, yet they remain heavily dependent on manual labor. To address this challenge, an autonomous screw handling system has been developed by integrating active compliance control with a hand–eye vision system, enabling both fastening and unfastening using a single robotic platform. A macro–mini manipulator structure is employed, where impedance control is applied to the mini arm to ensure stable contact forces during screw engagement. The vision system detects hole positions and tilt angles of the workpiece, effectively compensating for misalignment—especially in thin or deformable materials. This approach significantly reduces human intervention and enhances process reliability. Experimental results demonstrate that screws of various lengths can be fastened and unfastened with minimal insertion force, highlighting the potential of vision-guided automation in complex industrial environments.

Grinding with Impedance Control

  Impedance-controlled robotic grinding automates weld bead removal and surface finishing using 6-axis manipulator. A force/torque sensor at the tool center monitors contact, enabling contact-based reference alignment without external cameras. Grinding follows a two-stage rough-and-fine strategy: high-speed reciprocation first removes excess material, then segment-wise passes refine remaining irregularities. Real-time frequency analysis of vibration signals updates virtual stiffness, softening compliance over smooth portions and stiffening on uneven seams. A frequency threshold triggers an autonomous stop once desired smoothness is reached, preventing unnecessary wear. The control loop runs entirely on the robot controller with millisecond-rate feedback, while higher-level scripts handle path generation and parameter logging. A 3D-printed coupler integrates grinder, sensor, and dust extraction, forming a lightweight, modular end-effector that retrofits to standard industrial arms. The scheme shortens cycle time, ensures uniform finish quality, and shields human operators from debris and vibration.