M.Sc Thesis

M.Sc StudentLeiba Dvir
SubjectInertial Stabilization and Control of a Payload Installed on
a Maneuvering Platform
DepartmentDepartment of Mechanical Engineering
Supervisors PROF. Itzhak Porat
PROF. Alon Wolf
DR. Ilan Rusnak
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


This thesis deals with dual and single loop architectures for speed and state control systems for inertial servo drive systems.

One of the problems with tracking and guidance systems is their flexibility (degrees of freedom), which is a direct result of the mechanical structure of the system. One of the methods of dealing with the flexibility problem is implementing a   dual feedback loop. In this architecture, the inner loop is being closed on the motor’s rotor and the outer loop is being closed on the load or preload. In inertial systems, the maneuvers of the dynamic platform on which the system is placed have negative influence on the tracking performance.

In this study we have considered all the possible architectures for state and speed control tracking systems for single and dual feedback loops. Elements that vary in the different systems include speed and position sensors, their position in the control system architecture and their characteristics. A necessary condition for dual loop architecture design in inertial system has been formulated. The condition states that whether or not the architecture would better reduce the platform maneuvers depends on the inner and outer controllers. The different architectures and sensor characteristics have also been analyzed as to how well they reduce the platform disturbance. The analysis has shown that a dual loop system does not always better reduce the influence of the platform dynamics and the inner loop controller than a single loop system.

State and speed control simulations were then done. Based on our analysis and the architecture summary, we have selected the architectures that we thought would be more interesting for the readers. In this paper the simulated systems are more realistic and include two flexible modes. The first mode is between the motor rotor and the load and the second mode is between the load and the preload (the controlled inertia.) The simulated architectures are being compared by the quality of the tracking and the reduction of dynamic platform maneuvers. The main part of the simulations shows the use of a dual feedback loop in the different structures.  The simulations have shown that if we are looking only at the tracking performance of the systems, the dual feedback loop always yields better results. However, concerning the reduction of platform maneuvers, the results are unclear. The simulations results also verify the necessary condition that was stated above.