جستجوی مقالات مرتبط با کلیدواژه « توابع لاگر » در نشریات گروه « مکانیک »

One of the major challenges in the use of predictive control systems, particularly in the fast system is computational burden. To accelerate the process and reduce the amount of computation and optimization of functions, we use the Laguerre functions. The purpose of this paper is to provide a linear predictive control method using Laguerre functions with constraints on signal and the rate control signal for a helicopter flight control system design in the status of hover maneuver. By tuning parameters of predictive control in nonlinear model, the performance of the proposed method evaluate by two index entries, maneuverability and coupling effect based on standards for design a helicopter flight control system. Multiplicative uncertainty in state-space model has been described due to uncertainty on system modeling to study the robustness of the proposed method. The simulation results of this method have been compared with the results of generalized predictive control method. Simulation results show that in addition of public benefits in generalized predictive control, Laguerre predictive control has the advantage of reducing the time and burden of computation and it is clear to see that the control law we have obtained for the hovering flight condition achieve the top level performance in two categories under examination.

In this paper, a constrained predictive controller is designed using Laguerre functions to control the depth and steering of an autonomous underwater vehicle considering underwater disturbances. Due to under-actuated nonlinear coupled dynamics, parameters uncertainty, external underwater disturbances autonomous underwater vehicles are complicated. Moreover, the underwater autonomous vehicle investigated in this study includes constraints on actuators leading a more complex problem. In this study, first, the nonlinear dynamics of the autonomous underwater vehicle utilized for the controller design has been modeled. Then, Laguerre orthogonal functions were used in the constrained predictive controller design for reducing computational time and accelerating optimization process. Optimized, online, high precision, implementation capability, consider constraints purposefully and robust properties against disturbances can be mentioned as the most important advantages of designed controller. In addition, predictive control method is robust against disturbances. To monitor the methods’ performance, the autonomous underwater vehicle was modeled and then a comparison between the controller's calculation time with and without the Laguerre functions was also represented. At the end, the simulation results obtained from this controller, using Laguerre functions, showed the efficiency and effectiveness of the proposed solution.

In this paper, the design of predictive functional controller based on Laguerre functions to track the load changes in Pressurized Water Reactor (PWR) nuclear power stations has been considered. Since, despite of out-performance of predictive controllers in industrial applications, their implementation implies high computational complexity for constrained large scale systems, in this paper, the design of model predictive controller with low computational complexity was considered. For this purpose, at first, the order of PWR model was reduced via Balanced Truncation method. Then, due to low computational complexity and high performance of predictive functional controllers, we dealt with the design of predictive functional controllers based on Laguerre functions. In this context, the Laguerre polynomial scaling parameter was determined by minimizing integral square error. Then, due to mechanical constraints, some specific constraints were applied to the control effort and its changes, and the Quadratic Programming method was used for solving the constrained model predictive control problem and consequently, designing the control effort signal. Also, in order to show the efficiency of the proposed core power control method, the system response in the presence of disturbance is investigated. It is shown that, by using predictive functional controller on a reduced order model, in addition to the decrease of the computation volume, the performance of the core power control to track load changes in presence of external disturbance is well done.

Numerous studies have been devoted to motion control of wheeled mobile robots in recent years. Among them, trajectory tracking has received much attention.. A feed-forward and feedback control structure for trajectory tracking is used to circumvent the limitation of Brockett’s theorem. Feed-forward control is calculated according to the reference trajectory, it can not compensate instrumentation and initial state errors, therefore a feedback controller is utilized as well. In this paper a model predictive controller is used as the feedback controller. Since the initial state is not often matched to the desired trajectory, rapid tracking of the trajectory in early steps is very important. In this paper a model predictive controller with laguerre functions and another one with exponential data weighting is used to reduce tracking error in early steps. According to simulation results, reference trajectory tracking is improved through laguerre functions in model predictive controller.