scholarly journals Dynamic Modeling and Coupling Characteristic Analysis of Two-Axis Rate Gyro Seeker

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Shixiang Liu ◽  
Tianyu Lu ◽  
Teng Shang ◽  
Qunli Xia
Keyword(s):  
Block Diagram ◽  
Cross Coupling ◽  
Coupled System ◽  
Open Loop ◽  
Servo Control ◽  
Control Mode ◽  
Characteristic Analysis ◽  
Rate Gyro ◽  
Coupling Characteristics ◽  
Stabilized Platform

A dynamic model of a two-axis rate gyro-stabilized platform-based seeker with cross-coupling, mass imbalance, and disturbance torque is developed on the basis of the working principle of seeker two-loop steady tracking theory; coordinate transformations are used to analyze the effects of seeker servo control mode on missile guidance and control systems. Frequency domain is used to identify the servo motor transfer function. Furthermore, a block diagram of the two-gimbal-coupled system is developed, and the coupling characteristics of gimbal angle are analyzed with different missile body inputs. Simulation results show that the analysis conforms with the actual movement rule of seeker gimbal and optical axis, and cross-coupling exists between the two gimbals. The lag compensation network can increase the open loop gain and increase the capacity for disturbance rate rejection. Simulations validate the theory and technology support for developing the seeker servo control model in engineering.

The Derivation and Use of Aerodynamic Transfer Functions of Airframes

1955 ◽  
Vol 59 (539) ◽  
pp. 743-761 ◽  
Author(s):  
F. R. J. Spearman
Keyword(s):  
Transfer Functions ◽  
Block Diagram ◽  
Cross Coupling ◽  
Aerodynamic Characteristics ◽  
Open Loop ◽  
Control Surface ◽  
Electrical Networks ◽  
Servo Mechanism ◽  
Amplifier Design ◽  
Set Up

SummaryThe aerodynamic characteristics of airframes are expressed as aerodynamic transfer functions, giving the relationships between input and output for each of the three separate planes of motion, roll, pitch, and yaw. By assuming no cross-coupling between planes and linear aerodynamics, and by making certain other assumptions, which apply particularly to conventional airframes with fixed wings and rear controls, relatively simple approximate algebraic transfer functions giving the relationships between the control surface deflection (the input) and any airframe motion (the output), are obtained.The open loop aerodynamic transfer functions thus obtained are used as part of the auto-pilot block diagram, in which the performance of other components, such as actuators, instruments and electrical networks, are also expressed in transfer function form. The aerodynamic transfer functions are useful in auto-pilot evolution and synthesis in that they aid selection of the airframe motions to be measured, modified, and fed back to close the auto-pilot loop.For mathematical assessment of closed loop performance and stability, open loop transient and frequency responses are used, and curves of airframe responses are plotted in linear, logarithmic and polar form by standard methods from the aerodynamic transfer functions. Some methods of using these curves, which follow the general lines adopted in servo-mechanism and electronic amplifier design, are explained briefly.Analogue computers are frequently used when the computations to be made are so complicated as to need the use of a computing machine. The aerodynamic transfer functions then form one block of the simulator set-up, and on larger computers the more exact form, including any non-linearities and cross-coupling effects, can be used.

Line-of-sight rate modeling and error analysis of inertial stabilized platforms by coordinate transformation

2017 ◽  
Vol 233 (4) ◽  
pp. 1317-1322 ◽  
Author(s):  
Qingjia Gao ◽  
Qiang Sun ◽  
Feng Qu ◽  
Jiang Wang ◽  
Xizhen Han ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Target Tracking ◽  
Coordinate Transformation ◽  
Servo Control ◽  
Line Of Sight ◽  
Measurement Equations ◽  
Stabilized Platform ◽  
First Time ◽  
Guidance Laws ◽  
Key Parameter

Line-of-sight rate is the key parameter that enables inertial stabilized platforms to implement guidance laws successfully for target tracking or attacking. It is always obtained by experiments. In this article, a theoretical model of the line-of-sight rate is established for the first time, starting with the gimbal motion. The strategy to acquire line-of-sight rate is based on the servo control circuit. The measurement equations for line-of-sight rate are derived using a coordinate transformation. An error model is then obtained with the help of differentiation. The error of an inertial stabilized platform prototype is measured, showing that the line-of-sight rate error can be predicted accurately. Finally, a high-precision inertial stabilized platform is successfully designed and analyzed, with the accuracy of 0.06°/s and 0.37°/s when line-of-sight rates are set to 1.5°/s and 9°/s, respectively.

RFID Loop Tags for Merchandise Identification Onboard Ships

2014 ◽  
Vol 1036 ◽  
pp. 969-974
Author(s):  
Daniela Deacu
Keyword(s):  
Radio Frequency Identification ◽  
Block Diagram ◽  
Simulated Data ◽  
Open Loop ◽  
Closed Loops ◽  
Passive Tags ◽  
Received Power ◽  
Resonance Frequencies ◽  
Frequency Identification ◽  
Good Agreement

Radio frequency identification (RFID) is one of the most actual techniques employed to control the circuit of merchandises, as an alternative to the classical barecode. RFID tags should be cheap and easy to reproduct on a multitude of dielectric supports. There are several types of RFID systems, depending on whether tag and/or reader are active or passive. For cost reasons, merchandise identification should use active reader and passive tag, as the latter might be manufactured on a cheap FR4 support or printed directly on paper, by using a conductive ink. Passive tags can be shaped as straight dipoles, meandered dipoles, or loops. When a small area is required, loops are more appropriated. Codes are made different one from another by using on the same tag antennas with different resonance frequencies. Another advantage of loops is that they can be placed one inside other, so the occupied area is even smaller compared to other multi-resonant tags. Firstly, a single loop is analyzed, in order to model the resonant behaviour, correlated to the loop geometry and size. Open and closed loops are studied; the lowest resonance frequency for a given loop length is achieved for the open loop. In that case, the loop is resonating as a dipole. Next, a tag with three concentric loops is investigated. Separately, a small loop is used on the tag, in order to couple the received power in a resistor. When the tag is close to the reader, the latter is triggered if power is absorbed simultaneously on the three expected frequencies. The proposed tag was simulated and manufactured. Results show a good agreement between measured and simulated data. Finally, a block diagram for the reader was proposed.

scholarly journals On Stability of Open-Loop Operation without Rotor Information for Brushless DC Motors

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhong Wu ◽  
Haotun Lyu ◽  
Yongli Shi ◽  
Di Shi
Keyword(s):  
Theoretical Analysis ◽  
Operation Mode ◽  
Open Loop ◽  
Control Mode ◽  
Open Loop Control ◽  
Brushless Dc Motors ◽  
Loop Control ◽  
Rotor Position ◽  
Brushless Dc ◽  
Dc Motors

Open-loop operation mode is often used to control the Brushless DC Motors (BLDCMs) without rotor position sensors when the back electromotive force (EMF) is too weak due to the very low rotor velocity. The rotor position information is not necessary in this mode and the stator windings are supplied with voltages under a certain ratio of the amplitude to the frequency. However, the rotor synchronization will be destroyed once if the commutation instant is inappropriate. In order to improve the reliability of the open-loop operation mode, a dynamic equation is established to represent the synchronization error between the rotor and the stator. Thereafter, the stability of the open-loop control mode is analyzed by using Lyapunov indirect method. Theoretical analysis indicates that the open-loop control mode is asymptotically stable only when the commutation instant of the stator current lags behind the ideal one suitably. Finally, theoretical analysis is verified through the experimental results of a certain BLDCM.

Controlling the Transition From Stable Resting to Tracking Control of an Unstable System

2002 ◽  
Vol 124 (2) ◽  
pp. 303-307
Author(s):  
Pai-Hsueh Yang ◽  
David M. Auslander
Keyword(s):  
Resting State ◽  
Tracking Control ◽  
State Transition ◽  
Experimental System ◽  
Open Loop ◽  
Control Mode ◽  
Unstable System ◽  
On Line ◽  
Line Trajectory ◽  
Smooth State

This paper discusses the control problem of launching an open-loop unstable system from its resting state on a mechanical hard stop. Smooth state transition with the appropriate control mode is accomplished by fuzzy transition logic. A “soft tracking” algorithm with on-line trajectory planning is then employed to manage the system stabilization immediately following the launch. The strategies have been successfully applied to an experimental system consisting of a hydraulically balanced beam pivoted at its center.

Dynamic Characteristic Analysis of Spinal Motor Control Between 11- and 15-Year-Old Children

Motor Control ◽  
2016 ◽  
Vol 20 (3) ◽  
pp. 285-298
Author(s):  
Daniel H.K. Chow ◽  
Newman M.L. Lau
Keyword(s):  
Brownian Motion ◽  
Motor Control ◽  
Fractional Brownian Motion ◽  
Dynamic Characteristics ◽  
Open Loop ◽  
Characteristic Analysis ◽  
Spinal Curvatures ◽  
Analytical Technique ◽  
Spinal Motor ◽  
And Gender

Spinal motor control can provide substantial insight for the causes of spinal musculoskeletal disorders. Its dynamic characteristics however, have not been fully investigated. The objective of this study is to explore the dynamic characteristics of spinal motor control via the fractional Brownian motion mathematical technique. Spinal curvatures and repositioning errors of different spinal regions in 64 children age 11- or 15-years old during upright stance were measured and compared for the effects of age and gender. With the application of the fractional Brownian motion analytical technique to the changes of spinal curvatures, distinct persistent movement behaviors could be determined, which could be interpreted physiologically as open-loop behaviors. Moreover, it was found that the spinal motor control of 15-year-old children was better than that of 11-year-old children with smaller repositioning error and less curvature variability as well as shorter response time and smaller curvature deformation.

Analysis of the coupling characteristics of a tapered three-guide coupled system

1990 ◽  
Vol 8 (10) ◽  
pp. 1621-1629 ◽  
Author(s):  
Y. Cai ◽  
T. Mizumoto ◽  
Y. Naito
Keyword(s):  
Coupled System ◽  
Coupling Characteristics

Combining Motion Primitives and Image-Based Visual Servo Control

2020 ◽  
Author(s):  
Ghananeel Rotithor ◽  
Ashwin P. Dani
Keyword(s):  
Feedback Control ◽  
Open Loop ◽  
Servo Control ◽  
Visual Servo ◽  
Motion Generation ◽  
End Effector ◽  
Visual Servo Control ◽  
Dynamic Movement ◽  
Motion Primitive ◽  
Dynamic Movement Primitives

Abstract Combining perception feedback control with learning-based open-loop motion generation for the robot’s end-effector control is an attractive solution for many robotic manufacturing tasks. For instance, while performing a peg-in-the-hole or an insertion task when the hole or the recipient part is not visible in the eye-in-the-hand camera, an open-loop learning-based motion primitive method can be used to generate end-effector path. Once the recipient part is in the field of view (FOV), visual servo control can be used to control the motion of the robot. Inspired by such applications, this paper presents a control scheme that switches between Dynamic Movement Primitives (DMPs) and Image-based Visual Servo (IBVS) control combining end-effector control with perception-based feedback control. A simulation result is performed that switches the controller between DMP and IBVS to verify the performance of the proposed control methodology.

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