scholarly journals Design of Composite Feedback and Feedforward Control Law for Aircraft Inertially Stabilized Platforms

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Valerii Azarskov ◽  
Anatoly Tunik ◽  
Olha Sushchenko
Keyword(s):  
Control Systems ◽  
Feedforward Control ◽  
Design Method ◽  
Synergetic Effect ◽  
Measurement Unit ◽  
Control Law ◽  
Control Laws ◽  
Robustness Criterion ◽  
Two Stages ◽  
Invariance Theory

The design of the control systems of the inertially stabilized platforms (ISPs) as part of airborne equipment for the majority of aircraft has its peculiarity. The presence of rate gyros in the inertial measurement unit gives the possibility to measure the rotation rate of the ISP base, which is the main disturbance interfering with the ISP accuracy. Inclusion of the feedforward disturbance gain in the control law with the simplest PI feedback significantly improves the accuracy of stabilization by the invariance theory. A combination of feedback and feedforward controllers produces a synergetic effect, thus, improving ISP accuracy. This article deals with the design of the airborne ISP control systems consisting of two stages: the parametric optimization of the PI feedback control based on composite “performance-robustness” criterion and the augmentation of the obtained system with feedforward gain. To prove the efficiency of the proposed control laws, the simulation of the ISP was undertaken. We have used a simulation of the heading-hold system of the commuter aircraft Beaver and the yaw rate output of this closed-loop system we have used as a source of the disturbance. The results of modeling proved the efficiency of the proposed design method.

A New Congestion Controller for Multilayer Networked Control Systems with Persistent Disturbances

2010 ◽  
Vol 439-440 ◽  
pp. 805-810 ◽  
Author(s):  
Peng Liu
Keyword(s):  
Control Systems ◽  
Networked Control Systems ◽  
Feedforward Control ◽  
Initial Conditions ◽  
Optimal Solution ◽  
Networked Control ◽  
Suboptimal Control ◽  
Control Law ◽  
Non Linear ◽  
Persistent Disturbances

In this paper, a new congestion controller is developed to obtain a feedforward and feedback optimal control for networked control systems (NCS) with persistent disturbances. The disturbances have known dynamic characteristics but unknown initial conditions. The disturbance observer is proposed to make the feedforward control law realizable physically. In the approach only the non-linear compensating term, solution of a sequence of adjoint vector differential equations, is required iteration. By taking the finite iteration of non-linear compensating term of optimal solution sequence, a suboptimal control law for NCS with time delay can be obtained.

scholarly journals Adaptive Position/Force Control of a Robotic Manipulator in Contact with a Flexible and Uncertain Environment

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 32
Author(s):  
Piotr Gierlak
Keyword(s):  
Control Systems ◽  
Movement Control ◽  
Interaction Force ◽  
Resistance Force ◽  
Control Law ◽  
Robot Interaction ◽  
Control Laws ◽  
The Impact ◽  
Interaction Surface ◽  
Selection Of

The present paper concerns the synthesis of robot movement control systems in the cases of disturbances of natural position constraints, which are the result of surface susceptibility and inaccuracies in its description. The study contains the synthesis of control laws, in which the knowledge of parameters of the susceptible environment is not required, and which guarantee stability of the system in the case of an inaccurately described contact surface. The novelty of the presented solution is based on introducing an additional module to the control law in directions normal to the interaction surface, which allows for a fluent change of control strategy in the case of occurrence of distortions in the surface. An additional module in the control law is perceived as a virtual viscotic resistance force and resilient environment acting upon the robot. This interpretation facilitates intuitive selection of amplifications and allows for foreseeing the behavior of the system when disturbances occur. Introducing reactions of virtual constraints provides automatic adjustment of the robot interaction force with the susceptible environment, minimizing the impact of geometric inaccuracy of the environment.

TAILORING THE BIFURCATION DIAGRAM OF NONLINEAR DYNAMICAL SYSTEMS: AN OPTIMIZATION BASED APPROACH

2010 ◽  
Vol 20 (04) ◽  
pp. 1027-1040 ◽  
Author(s):  
PIETRO ALTIMARI ◽  
ERASMO MANCUSI ◽  
MARIO DI BERNARDO ◽  
LUCIA RUSSO ◽  
SILVESTRO CRESCITELLI
Keyword(s):  
Bifurcation Diagram ◽  
Nonlinear Dynamical Systems ◽  
Feedforward Control ◽  
Nonlinear Dynamical System ◽  
Chemical Reactor ◽  
Control Law ◽  
Control Laws ◽  
Nonlinear Dynamical ◽  
Output Behavior ◽  
Objective Functional

Bifurcation tailoring is a method developed to design control laws modifying the bifurcation diagram of a nonlinear dynamical system to a desired one. In its original formulation, this method does not account for the possible presence of constraints on state and/or manipulated inputs. In this paper, a novel formulation of the bifurcation tailoring method overcoming this limitation is presented. In accordance with the proposed approach, a feedforward control law generating an optimal bifurcation diagram is computed by constrained minimization of an objective functional. Then, a feedback control system enforcing stability of the computed equilibrium branch is designed. In this context, bifurcation analysis is exploited to select feedback controller parameters ensuring desired output behavior and, at the same time, preventing the occurrence of multistability. The method is numerically validated on the problem of tailoring the bifurcation diagram of an exothermic chemical reactor.

Piecewise-Linear-Gain Pulse Width Control for Precise Positioning of Structurally Flexible Systems Subject to Stiction and Coulomb Friction

2004 ◽  
Vol 126 (1) ◽  
pp. 139-143 ◽  
Author(s):  
David B. Rathbun ◽  
Martin C. Berg ◽  
Keith W. Buffinton
Keyword(s):  
Pulse Width ◽  
Position Control ◽  
Design Method ◽  
Industrial Robot ◽  
Piecewise Linear ◽  
Gain Control ◽  
Quantitative Measure ◽  
Performance Measure ◽  
Control Law ◽  
Control Laws

Pulse width control refers to the use of a control law to determine the duration of fixed-height force pulses for point-to-point position control of a plant that is subject to mechanical friction, including stiction. A quantitative measure of the performance of a pulse width control system is introduced. Applications of this measure suggest that piecewise-linear-gain pulse width control laws will often provide better performance than constant-gain pulse width control laws. A method for designing piecewise-linear-gain pulse width control laws is introduced. The performance measure and piecewise-linear-gain control law design method are demonstrated in applications to the control of the position of the end-effector of an industrial robot.

Design of Finite Time Settling Regulators for Linear Systems

1994 ◽  
Vol 116 (4) ◽  
pp. 602-609 ◽  
Author(s):  
Slim Choura
Keyword(s):  
Finite Time ◽  
Feedforward Control ◽  
Linear Quadratic Regulator ◽  
Control Law ◽  
Control Input ◽  
Linear Quadratic ◽  
Control Laws ◽  
Performance Specifications ◽  
The Time Domain ◽  
State Responses

Earlier development of finite time settling controllers focused on the structure of the control law which consists of feedback and feedforward parts. In this structure, the feedback part is designed separately to satisfy certain performance specifications in the frequency and/or the time domain. The feedforward part is determined from the feedback control law, and therefore, there exists one-way coupling of both parts. In this paper, we propose a modification in the control structure that enables the designer to regulate the bounds of the control input and the state responses. We show that the finite time settling control problem can be transformed into a linear quadratic regulator one. This transformation results in a two-way coupling of the feedback and the feedforward control laws. We verify that the robustness property of the control strategy is preserved despite its structural change. In addition, we give guidelines for the selection of the feedforward control law.

scholarly journals Learning Feedforward Control Using Multiagent Control Approach for Motion Control Systems

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 420
Author(s):  
Phong B. Dao
Keyword(s):  
Real Time ◽  
Feedforward Control ◽  
Design Method ◽  
Mechatronic Systems ◽  
Control Approach ◽  
Runtime Environment ◽  
Multiagent Control ◽  
On Line ◽  
Promising Solution ◽  
Function Approximator

Multiagent control system (MACS) has become a promising solution for solving complex control problems. Using the advantages of MACS-based design approaches, a novel solution for advanced control of mechatronic systems has been developed in this paper. The study has aimed at integrating learning control into MACS. Specifically, learning feedforward control (LFFC) is implemented as a pattern for incorporation in MACS. The major novelty of this work is that the feedback control part is realized in a real-time periodic MACS, while the LFFC algorithm is done on-line, asynchronously, and in a separate non-real-time aperiodic MACS. As a result, a MACS-based LFFC design method has been developed. A second-order B-spline neural network (BSN) is used as a function approximator for LFFC whose input-output mapping can be adapted during control and is intended to become equal to the inverse model of the plant. To provide real-time features for the MACS-based LFFC system, the open robot control software (OROCOS) has been employed as development and runtime environment. A case study using a simulated linear motor in the presence of nonlinear cogging and friction force as well as mass variations is used to illustrate the proposed method. A MACS-based LFFC system has been designed and implemented for the simulated plant. The system consists of a setpoint generator, a feedback controller, and a time-index LFFC that can learn on-line. Simulation results have demonstrated the applicability of the design method.

A Design Method of LS-SVM Based Stable Adaptive Controller for a Class of Nonlinear Systems

2011 ◽  
Vol 48-49 ◽  
pp. 17-20
Author(s):  
Chun Li Xie ◽  
Tao Zhang ◽  
Dan Dan Zhao ◽  
Cheng Shao
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Nonlinear Function ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Control Law ◽  
Continuous Systems ◽  
Control Schemes ◽  
Closed Systems ◽  
Simulation Results

A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

scholarly journals On Existence of Stabilizing Switching Laws within a Class of Unstable Linear Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sendren Sheng-Dong Xu ◽  
Chih-Chiang Chen
Keyword(s):  
Control Systems ◽  
Linear Systems ◽  
Switched Systems ◽  
The Other ◽  
Linear Control ◽  
Linear Control Systems ◽  
Problem Statement ◽  
Theoretical Derivation ◽  
Control Laws ◽  
Numerical Examples

The equivalence of two conditions, condition (3) and condition (4) stated in Problem Statement section, regarding the existence of stabilizing switching laws between two unstable linear systems first appeared in (Feron 1996). Although Feron never published this result, it has been referenced in almost every survey on switched systems; see, for example, (Liberzon and Morse 1999). This paper proposes another way to prove the equivalence of two conditions regarding the existence of stabilizing switching laws between two unstable linear systems. One is effective for theoretical derivation, while the other is implementable, and a class of stabilizing switching laws have been explicitly constructed by Wicks et al. (1994). With the help of the equivalent relation, a condition for the existence of controllers and stabilizing switching laws between two unstabilizable linear control systems is then proposed. Then, the study is further extended to the issue concerning the construction of quadratically stabilizing switching laws among unstable linear systems and unstabilizable linear control systems. The obtained results are employed to study the existence of control laws and quadratically stabilizing switching laws within a class of unstabilizable linear control systems. The numerical examples are illustrated and simulated to show the feasibility and effectiveness of the proposed methods.

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