3-DOF Series-Spherical-Mechanism Control for Attitude Tracking in Inertial Space

Angle tracking control in inertial space is quite important in production and life. To avoid the defect of large volume weight and small load ratio of traditional tracking platform, an angular tracking platform based on a series-spherical-mechanism was designed. The modeling and control are difficult for such mechanisms. Based on the design, the kinematics modeling and controller of series-spherical-mechanism were proposed. Forward and inverse kinematics models were obtained by using the D-H parameter method. In this paper, the PID control system based on disturbance observer (DOB) is used for tracking control. The experimental device was built to collect the actual sensor data and verify the tracking effect. The experiments illustrate that the kinematics models are correct. In addition, the responses of the series-spherical-mechanism angle tracking platform to the tracked target motions are reliable.