Visual Inverse Kinematics for Cotton Picking Robot

Fast cotton picking requires a fast moving arm. Cartesian arm remains the most simple and quick moving arm compared to other configurations. In this study, investigation of the 2D Cartesian arm controlled with a stepper-drive is investigated. The arm is designed and mounted to a research rover. Two stereo cameras are installed and used to take the images of the cotton plants in two different angles. One camera is directly pointing downward while the other camera is pointing perpendicular to the row. This configuration allows the robot to view the cotton plants and bolls. The robot arm can move upward and downward or left and right. The robot uses its linear servos connected to a variable displacement pump swashplate for powering four hydraulic wheel motors and the engine accelerator linkage to move forward. It makes the cotton-picking robot arm movement 3-dimensional. The downward camera gives feedback to the robotic system on the position of the arm. The rover moves forward along the row and stops whenever the cotton boll is perpendicular to the cartesian arm. The sideways camera gives an alternative view of the cotton boll that allows the robot servos to stop accurately. The arm uses vacuum suction to pick the cotton bolls. The vacuum suction end effector is mounted on the arm and pointing sideways of the row. In this paper, the movement of the cotton arm and boll picking are demonstrated.