Robust optimal attitude control of a laboratory helicopter without angular velocity feedback

Robotica ◽  
2014 ◽  
Vol 33 (2) ◽  
pp. 282-294 ◽  
Author(s):  
Hao Liu ◽  
Jianxiang Xi ◽  
Yisheng Zhong
Keyword(s):  
Angular Velocity ◽  
Attitude Control ◽  
Control Method ◽  
Linear Time ◽  
Real System ◽  
Velocity Feedback ◽  
The Real ◽  
Linear Time Invariant ◽  
Optimal Output ◽  
Asymptotic Tracking

SUMMARYIn this paper, the robust, optimal, output control problem is dealt with for a 3-degree-of-freedom laboratory helicopter. The control goal is to achieve the practical tracking of the desired elevation and pitch angles without the angular velocity feedback. A nominal linear time-invariant system is introduced and the real system is considered as the nominal one with uncertainties, including parameter perturbations, nonlinear time-varying uncertainties, and external disturbances. An observer is first used to estimate angular velocity. Then a nominal controller based on the optimal control method is designed for the nominal system to achieve the desired tracking properties. Lastly, a robust output compensator is added to restrain the effects of uncertainties in the real system. It is shown that asymptotic tracking properties and robust stability can be achieved. Experimental results on the laboratory helicopter are shown to verify the effectiveness of the proposed control method.

Continuous control of sampled data systems with robustness against bounded measurement errors

2017 ◽  
Vol 40 (10) ◽  
pp. 3125-3133
Author(s):  
Milad Ghanbari ◽  
Masoud Bahraini ◽  
Mohammad Javad Yazdanpanah
Keyword(s):  
Measurement Errors ◽  
Control Method ◽  
Linear Time ◽  
Continuous Control ◽  
Data Systems ◽  
Sampled Data ◽  
Linear Time Invariant ◽  
Experimental Implementation ◽  
Time Invariant ◽  
Ultimate Bound

This paper considers the design of a generalized hold function to be used for the control of sampled-data systems. The proposed method suggests a continuous controller for sampled data systems. Ultimate boundedness of the proposed method in the presence of bounded measurement errors is also shown for linear and nonlinear systems. In linear time invariant cases, a cost function is suggested for the sake of ultimate bound minimization. In addition, this can answer how we choose a sensor for a real system to get a desired control outcome. Eventually, the effectiveness of the proposed control method is investigated through simulation and experimental implementation.

Discrete Linear Time Invariant Analysis of Digital Fluid Power Pump Flow Control

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Per Johansen ◽  
Daniel B. Roemer ◽  
Torben O. Andersen ◽  
Henrik C. Pedersen
Keyword(s):  
Flow Control ◽  
Discrete Time ◽  
Control Method ◽  
Linear Time ◽  
Linearization Method ◽  
Fluid Power ◽  
Linear Time Invariant ◽  
Pump Flow ◽  
Linear Control Theory ◽  
Time Linear

A fundamental part of a digital fluid power (DFP) pump is the actively controlled valves, whereby successful application of these pumps entails a need for control methods. The focus of the current paper is on a flow control method for a DFP pump. The method separates the control task concerning timing of the valve activation and the task concerning the overall flow output control. This enables application of linear control theory in the design process of the DFP pump flow controller. The linearization method is presented in a general framework and an application with a DFP pump model exemplifies the use of the method. The implementation of a discrete time linear controller and comparisons between the nonlinear model and the discrete time linear approximation shows the applicability of the control method.

A Control Method for Non-Linear Time-Varying System Using Mixed H2/H∞ Control: Position and Force Control of 2-Link Manipulator

2001 ◽  
Author(s):  
Itsuro Kajiwara ◽  
Katsuhiro Yambe ◽  
Chiaki Nishidome
Keyword(s):  
Control Method ◽  
Linear Time ◽  
Gain Scheduling ◽  
Operating Conditions ◽  
Pole Placement ◽  
Time Varying ◽  
Linear Time Invariant ◽  
Highly Nonlinear ◽  
Switching Controller ◽  
Time Invariant

Abstract Dynamics of multi-link manipulators are highly nonlinear and depend on the time varying configuration. This paper presents a method of gain scheduling which consists in designing a linear time invariant (LTI) controller for each operating point and in switching controller when the operating conditions change. Each LTI controller is designed based on LMI approach in which an optimization problem is defined as a mixed H2/H∞ control problem with pole placement. The performance of the force and the position controls is defined by the H2 norm, and the robust stability according to gain scheduling is evaluated with the H∞ norm and the pole placement of the closed-loop system. The effectiveness and the practicability of the proposed method are verified by both simulations and experiments with 2-link manipulator system.

A Time Delay Controller for Systems With Unknown Dynamics

1990 ◽  
Vol 112 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Kamal Youcef-Toumi ◽  
Osamu Ito
Keyword(s):  
Time Delay ◽  
Control Method ◽  
Linear Time ◽  
Structure Stability ◽  
State Variables ◽  
Single Input Single Output ◽  
Linear Time Invariant ◽  
Single Output ◽  
Single Input ◽  
Time Invariant

This paper focuses on the control of systems with unknown dynamics and deals with the class of systems described by x˙=f(x,t) + h(x,t) + B(x,t)u + d(t) where h(x,t) and d(t) are unknown dynamics and unexpected disturbances, respectively. A new control method, Time Delay Control (TDC), is proposed for such systems. Under the assumption of accessibility to all the state variables and estimates of their delayed derivatives, the TDC is characterized by a simple estimation technique that evaluates a function representing the effect of uncertainties. This is accomplished using time delay. The control system’s structure, stability and design issues are discussed for linear time-invariant and single-input-single-output systems. Finally, the control performance was evaluated through both simulations and experiments. The theoretical and experimental results indicate that this control method shows excellent robustness properties to unknown dynamics and disturbances.

scholarly journals Microsatellite Attitude Determination and Control Subsystem Design and Implementation: Software-in-the-Loop Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ho-Nien Shou
Keyword(s):  
Angular Velocity ◽  
Normal Mode ◽  
Attitude Control ◽  
Attitude Determination ◽  
Control Method ◽  
Measurement Data ◽  
Low Earth Orbit ◽  
Control Subsystem ◽  
Institute Of Technology ◽  
And Control

The paper describes the development of a microsatellite attitude determination and control subsystem (ADCS) and verification of its functionality by software-in-the-loop (SIL) method. The role of ADCS is to provide attitude control functions, including the de-tumbling and stabilizing the satellite angular velocity, and as well as estimating the orbit and attitude information during the satellite operation. In Taiwan, Air Force Institute of Technology (AFIT), dedicating for students to design experimental low earth orbit micro-satellite, called AFITsat. For AFITsat, the operation of the ADCS consists of three modes which are initialization mode, detumbling mode, and normal mode, respectively. During the initialization mode, ADCS collects the early orbit measurement data from various sensors so that the data can be downlinked to the ground station for further analysis. As particularly emphasized in this paper, during the detumbling mode, ADCS implements the thrusters in plus-wide modulation control method to decrease the satellite angular velocity. ADCS provides the attitude determination function for the estimation of the satellite state, during normal mode. The three modes of microsatellite adopted Kalman filter algorithm estimate microsatellite attitude. This paper will discuss using the SIL validation ADCS function and verify its feasibility.

Design of Multi-Stage Optimal Arbitrary Time-Delay Filter

2013 ◽  
Vol 397-400 ◽  
pp. 1510-1514 ◽  
Author(s):  
Ke Ping Liu ◽  
Jian Peng Zeng ◽  
Min Yang ◽  
Chang Hong Jiang
Keyword(s):  
Time Delay ◽  
Control Method ◽  
Linear Time ◽  
Residual Vibration ◽  
Arbitrary Time ◽  
Linear Time Invariant ◽  
Flexible System ◽  
Multi Stage ◽  
Linear Time Invariant System ◽  
Time Invariant

Input shaping is an effective method for suppressing residual vibration of flexible system. In this paper, the design processes of Zero Vibration (ZV), Zero Vibration and Derivative (ZVD) shapers are deduced. Based on the idea of the robustness input shaper, the Multi-stage Optimal Arbitrary Time-delay Filter (MOATF) is proposed. The proposed control method is implemented on the second-order linear time-invariant system. Simulation results show that the residual vibration can be reduced effectively and the proposed method have great robustness in system parameter uncertainty.

Design of an Electrohydraulic Positioning System Using a Novel Model Reference Control Scheme

1989 ◽  
Vol 111 (2) ◽  
pp. 292-298 ◽  
Author(s):  
N. Hori ◽  
A. S. Pannala ◽  
P. R. Ukrainetz ◽  
P. N. Nikiforuk
Keyword(s):  
Control Method ◽  
Linear Time ◽  
Design Method ◽  
Sampling Interval ◽  
Model Reference ◽  
Linear Time Invariant ◽  
Model Reference Control ◽  
Servo Actuator ◽  
Potential Applications ◽  
Linear Time Invariant System

A new model reference control method is presented for a linear, time-invariant system which may have multiple inputs and outputs. The design method is described in the discrete-time form using the Euler operator, which approaches the Laplace operator as the sampling interval aproaches zero. This method is applied to the positioning control of an electrohydraulic servo actuator and implemented using a personal computer in real time. The experimental results show that the plant response is significantly improved using the proposed method over the conventional output feedback method. The proposed method has potential applications to robots and other servomechanisms.

Mixed H2/H∞ Control Approach and its Application in Satellite Attitude Control System

2016 ◽  
Vol 25 ◽  
pp. 89-97 ◽  
Author(s):  
Chuang Liu ◽  
Zhao Wei Sun ◽  
Ke Ke Shi ◽  
Feng Wang
Keyword(s):  
Attitude Control ◽  
Linear Time ◽  
Linear Matrix ◽  
Feedback Gain ◽  
Control Input ◽  
Attitude Control System ◽  
Control Approach ◽  
Linear Time Invariant ◽  
Satellite Attitude ◽  
Linear Time Invariant System

In this paper, we address the mixed H2/H∞ control approach for linear time-invariant system based on linear matrix inequality (LMI). First, the problem to be solved is stated, and the satellite attitude dynamics is established and converted into a corresponding state space form. Then, the mixed H2/H∞ controller based on LMIs is designed in order to attain the state feedback gain matrix. To validate the efficiency and practicability of the proposed controller, simulation results based on satellite attitude system are presented, from which we can observe that under the condition of external disturbances, the system will be stable within 150s, and the maximum of control torque will be no more than 0.025Nm. Expanding the controller gain will affect the stabilizing process, but not the stabilization time, and it will increase the control input which will bring pressure to the actuator.

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