Research of the feedforward control system of 3-axis stable platform based on disturbance observer

Abstract

In order to improve stability and capability of rejecting disturbance of the platform, the feedforward controller and disturbance observer (DOB) are used in angular loop of the 3-axis stabilized platform. This method can effectively avoid the conflict between stability and rapidity of system. Using the error signal as the evaluation index, the DOB can accurately track external disturbances, such as constant, periodic and random disturbance signal, eliminate model mismatches and improve the stability and robustness of the inner loop. Finally, the simulation result shows that the composite control method has better dynamic performance and smaller steady-state error than cascade lead-lag compensation.

Anti-Swaying Control Strategy of Ship-Mounted 3-RCU Parallel Platform Based on Dynamic Gravity Compensation

“…The dynamic model of the system was established, the effects of friction, inertia, and torque motors were considered, and a control structure consisting of three control loops was developed through the concept of decentralized control, the feasibility of which was verified by simulation. Sui et al designed a three-axis tandem stage to improve the tracking accuracy and response speed of the stage by using a conventional proportional-integral-derivative (PID) controller with a feedforward velocity loop [7]. Serial motion compensation platforms have been industrialized and widely used, but their limitations in carrying capacity, response speed, and positional accuracy affect their application in certain scenarios [8].…”

“…In recent years, there has been more and more research on wave compensation control strategies, and they are focused on different application scenarios and proposed various control methods for wave motions with different degrees of freedom [15][16][17]. Sui et al proposed a three-degrees-of-freedom-stabilized platform control method consisting of a feedforward controller and a disturbance observer and verified the advantages of the combined control method in terms of dynamic performance and steady-state error through simulation [7]. Campos et al used the Stewart platform as an active helideck to ensure the safety of a helicopter landing at the ocean, and they used the traditional proportional derivative (PD) control for wave compensation, which was experimentally verified to be effective [18].…”