Visual servoing control schemes of 4 DOF robot manipulators

In this research, three vision-based control schemes are proposed to control a 4-DOF manipulator that uses parallelogram mechanisms to keep the end-effector always parallel to the horizontal. The image features including area, orientation, and centroid are used as input to control four velocities components of the robot in the first scheme. The other two schemes are affine transformation-based and homography-based controllers, respectively. In the homography-based controller, the homography matrix is directly used to design the controller without performing decomposition as shown in the previously developed schemes. The camera intrinsic and extrinsic parameters do not need to be calculated in all three suggested methods while performing. The effectiveness and simplicity of the proposed schemes are proved through a series of simulations.