Jarod TangRobotics Engineer, MEng
The finished 4-DOF chess manipulator with clear acrylic truss links on a workshop bench.

Chess Playing Robot.

  • Robotics Systems
  • 4-DOF
  • Kinematics
  • Task-space control

A 4-DOF robotic arm designed, built and programmed to move chess pieces, from kinematics on paper to a working machine on the bench.

Reports

Kinematic diagram of the arm's four joints and link lengths.

Kinematics.

Forward and inverse kinematics derived with the Denavit–Hartenberg convention, then a Jacobian relating joint velocities to end-effector motion and the torques each joint must supply.

CAD assembly of the arm showing truss links, servo joints and the geared base.

Design.

Truss-style links, a geared base and a simple, easily modified end effector, designed in CAD so parts could be remade quickly as the software matured.

3D plot of a planned end-effector trajectory with the arm's pose overlaid.

Control.

Quintic polynomial trajectories for smooth motion between poses, then task-space velocity control on the final build, with the base raised 85 mm above the board.

  • The built arm reaching over the chessboard.
  • Close-up of the arm's end effector.
  • Geared base and first joint of the arm.
  • Second joint of the arm with its servo and mounting.
  • Third joint of the arm with its servo and mounting.
  • CAD model of the geared base.
  • CAD side view of the end effector.