Курчаткина Г.П., Стручкова С.Б. Обучение чтению литературы на англ.языке по спец. САУ для студентов старших курсов (2014) (1257062), страница 5
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In this system, deflection of an aerodynamic controlsurface, such as a tail fin, is the control input, and pitch angular rate (q) andacceleration (Az) are measured by the IMU for feedback to the autopilot. Thecontrol deflection produces a small aerodynamic force on the tail fin but a largemoment on the airframe because of its lever arm from the center of mass.
Theinduced moment rotates the missile to produce the AOA, which in turn producesaerodynamic lift to accelerate the airframe.The error between the commanded and achieved acceleration is used as aninput to the inner control loops that control missile pitch rate. The pitch ratecontrol loops include integration with respect to time that is implemented incircuitry for an analog autopilot or with numerical difference equations in acomputer in a digital autopilot.
The three control gains are selected so that theclosed-loop flight control system has the desired speed of response and robustnessconsistent with other design constraints such as actuator limits.Attitude Control SystemThе attitude control system also has a three-loop structure like theacceleration control system. In this case, the control effector is the thrust-deflection29angle that is actuated by either a nozzle or jet tabs.
The feedback loops have astructure similar to that used in the acceleration control system, except that theouter loop is pitch-angle feedback instead of acceleration. The numerical values ofthe gains in the control loops may differ for controlling attitude compared tocontrolling translational acceleration. The integration of pitch rate measured bythe IMU to pitch attitude would typically be done via discrete integration in themissile navigation processing in the flight computer.Flight-Path Angle Control SystemThis type of system assumes that aerodynamic forces are small and henceapplies for exoatmospheric flight or for endoatmospheric flight when the missilespeed is low.
In this design, the feedback loops reflect the underlying physicalrelationships among the flight-path angle, AOA, flight-path angle rate, and pitchrate. The design explicitly uses estimates of the missile thrust and mass propertiesto compensate for how the missile dynamics change as propellant is expanded. Thecommanded input into the autopilot is the desired flight-path angle. The output isthe thrust-vector deflection angle.(2410)Task 15. Divide the text into logical parts. Choose the key sentences from the textand translate them.Task 16. Explain the difference among the specific types of flight control systems.Task 17.
Get ready to make a written abstract and a summary of the text.Task 18. Work in groups of two, A and B. Read text D on flight control systemdesign objectives and make brief notes on the main points of one of the two parts ofthe text.Text D. Flight Control System Design ObjectivesThe particular figures of merit (FOMs) used to evaluate the flight control systemare application dependent.
Flight control system FOMs can be expressed in thetime and frequency domains.Time-domain Design ObjectivesSome basic FOMs of a flight control system that are measured in the time domaindefine how quickly the missile will respond to a change in guidance command and30also the deviation of the achieved missile motion relative to the command. Forexample, the time constant and rise time characterize how quickly the systemresponds to the change in the command.
The percentage overshoot and peakamplitude characterize the degree to which the response is well controlled. Thesteady-state error and settling time are indicators of how well the system tracks thedesired command. Designing the flight control system can require trade-offsbetween these FOMs. For example, a system that requires a small time constantmay have to suffer larger overshoots.Frequency-Domain Design ObjectivesFrequency-domain requirements are based on the classical control theory ofNyquist and Bode and are primarily concerned with quantifying the robustness ofthe flight control system.
Robustness is important because the flight control systemis designed based on models of the missile dynamics, actuator, and IMU, whichare inherently approximations (i.e., no model is perfect). Qualitatively, robustnessis the degree to which the flight control system can tolerate the error between theassumed models and the real system.(1289)Task 19. Now share the information about your text with others in your group.Task 20. Search the Web for additional material in order to provide an overviewof missile flight control systems. Summarize the information on the issue and makea presentation.31APPENDICESGrammar RevisionExercise 1.
Translate the sentences into Russian paying attention to Passive Voice.1. State equation, transfer function, and even impulse response can be used as thepredictive model.2. With the advent of digital electronic engine controls this non-linear problem iseasily taken care of using software.3. An important feature of the feedback control system is that external disturbanceswhich affect the response of the process will be sensed, and ultimatelycompensated for by the controller.4. Requirements on the flying and handling qualities are simply present and theyhave to be followed.5.
Airplane flying qualities can be badly affected by a lag in the signal that is sentto an actuator or a lag in an actuator itself.6.An adaptive control system can be thought of as having two loops. One loop isthe normal closed-loop feedback with the plant and controller. The other loop isthe parameter adjustment loop which takes a combination of the command input,control signal and output response and adjusts the controller parametersaccordingly.7. The parameters of a system such as rise time, settling time, overshoot and steadystate error can be influenced by using the PID controller8.The fuzzy rule set becomes more complex if the fuzzy level state associated withmore than one signal must be accounted for.9. The status or the configuration of the JET machine (JET - Joint European Torus– термоядерный реактор “Токамак” стран Европейского экономическогосообщества) cannot be taken into account by a system on its own.10.
The design choice is typically driven by the necessity to facilitate integratedtesting between plasma control facilities and their related diagnostic or actuator.32Exercise 2. Translate the sentences into Russian paying attention to Participle.1. Any desirable design method should yield a robust control system whenproperly applied.2. Having applied the method presented we could find a variation law of theregulator coefficient.3. Engineered systems are often made up of modules that are designed to operate inessentially linear fashion, with any nonlinearities introduced in carefully selectedlocations and forms.4.The processing of analog signals is performed using components such asresistors and capacitors, with actual values varying significantly from the nominaldesign values.5. The results of these analyses are communicated back to the contractor, withemphasis being on areas of concern and potential solutions that may need to beaddressed in a subsequent design iteration.6.
Universal algorithmic methods created provide the possibility to solve differentproblems of the control system synthesis.7. Although originally derived for a linear problem, the Kalman filter is habituallyapplied with considerable success to many nonlinear problems.8.
Most actuators are electromechanical, with hydraulic actuators being an optionin certain applications.9. If not handled properly, faults developing on some Tokamak elements couldresult in severe damage to the machine.10. Originally developed to meet the specialized control needs of power plants andpetroleum refineries, model predictive control technology can now be found in awide variety of application areas.11. Based on three common ancestors, train control systems have been developedhistorically in many different ways throughout the railway companies.12. Modern Identification Friend or Foe system is a two-channel system, with onefrequency used for the interrogating signals and another for the reply.3313.
With the center of pressure located in the right place, the rocket will remainstable.Exercise 3. Translate the sentences into Russian paying attention to functions ofInfinitive.1. To control the measurement is to keep it within acceptable limits.2. To control the temperature manually the operator is to watch the indicatedtemperature, and by comparing it with the desired temperature, to open or close thevalve to admit more or less steam .3. The challenge for the control system designer is to establish the best controlalgorithm that will provide the optimum performance in terms of accuracy,dynamic response and stability.4.
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