【機(jī)械類畢業(yè)論文中英文對照文獻(xiàn)翻譯】雷達(dá)天線伺服系統(tǒng)結(jié)構(gòu)與控制
【機(jī)械類畢業(yè)論文中英文對照文獻(xiàn)翻譯】雷達(dá)天線伺服系統(tǒng)結(jié)構(gòu)與控制,機(jī)械類畢業(yè)論文中英文對照文獻(xiàn)翻譯,機(jī)械類,畢業(yè)論文,中英文,對照,對比,比照,文獻(xiàn),翻譯,雷達(dá),天線,伺服系統(tǒng),結(jié)構(gòu),控制,節(jié)制
黃河科技學(xué)院畢業(yè)設(shè)計（外文資料） 第 13 頁
Structure And Control Radar Antenna Servo System
Summary
Radar antenna mainly depends on the level of its servo system design. Design of servo system design including design and control of two parts, interaction between these two parts are tightly coupled. General system design method is used to structure and control system design, respectively, and then adjusted according to the requirements, which often leads to long product development cycles, high cost, poor performance, structure of heavy, cannot ensure the overall performance of optimal servo system. For the radar antenna servo system design of structure and control design of phase separation problem, proposed a model of integrated optimization design of structure and control, gives the solution strategies and methods, and in turn, applied to the three typical examples, made satisfactory results. Numerical examples and real tests have verified the above radar antenna servo system integrated structure and control of the validity and correctness of the design models and methods. The model and method for other designs also have some reference of the servo system and its reference value.
1 Introduction
Mechanical and electrical system is a body (or structure) and the control of two subsystems, integrated design of both is necessary. Structure and control integrated design of research since in the 1980 of the 20th century began yilai, both at home and abroad scholars for has fruitful of research, main set in is as follows 3 a area: ① space system structure and control of integrated design, especially flexible structure system, select structure rod pieces of cross section for design variable, structure of quality and control energy for target, but does not adaptation Yu variable structure (or institutions) problem; ② DC motor of structure and control of integrated design problem, to DC motor for cases, from state space model start, Study on coupling between the structure and control, pointed out the need for integrated design, but for complex institutions, its state space model are not easy to obtain; ③ system bodies and control integration (or collaborative, parallel) design problem, according to the concept of integrated design agency. Natural frequencies of these institutions was not considered, dynamic target tracking control of nonlinear constraints such as stability, accuracy and speed, is no lightweight and gives both the institution and tracking control for more integrated design model of stable, accurate and fast.
2 Ask a question
Radar antenna pointing precision and fast response of performance depends on the level of its servo system design, design of servo system design including design and control of two parts. Realization of structure design affects performance, such as the realization of servo bandwidth depends on the natural frequency of the structure. In turn, the control will affect the structure of the design, such as driving force of servo system will affect the size of antenna pedestal structure design. Therefore, in order to achieve the "look" and "clearly" targets, structure design and controls must be integrated.
Traditional radar antenna servo system design is the design of phase separation of design and control that individual design of mechanical structure and controlling system, adjusted to meet required targets. As a matter of fact, structure and control radar antenna servo system is coupled to each other, especially in the high-performance tracking and coupling of the two are very close. If you failed to fully consider the servo to control design structure characteristics, will cause a reduction in performance of servo tracking, even unable to meet the requirement of performance indicators on the other, who fails to fully consider the control at design time, you can't be optimal design, could not even designed to meet the performance requirements of the structure. This design method of separation results in long product development cycles, high cost, poor performance and structure of heavy.
3 Structural analysis of radar antenna systems
Aims of structural design of mechanical structure design of servo performance requirements are met. To get a good servo to track performance, small quality general requirements for mechanical structure, good rigidity, however these requirements tend to be contradictory. To this end, the introduction of structural optimization, on quality and topology structure optimization design of distribution, transmission, stiffness requirements to achieve total quality guarantee or take up minimum space. In the body during exercise and its configuration changes over time. To this end, to mention it as a multiple-condition (it may be set to N1 indifferent conditions) of structure optimization problem (Figure 1).
Figure 1 structure optimization design of radar antenna systems
Solution
In the d radar servo structure design, N2 is total number of design variables.
Objective function for the total mass of the structure of the minimum
Type a and b respectively for simple structural parameters (such as body size, material, and so on) and depends on the structure design of control elements (such as driving), N3 for radar servo number of members structure, Vi as a component volume I, I for the I component of the material density. Constraints include first-order natural frequency constraints and stress and displacement constraints
In the structure under Frei as I pitch, f RE1 first-order natural frequencies of the smallest allowable value; e-unit under EJ and stress of actual value to the maximum allowable value; IJ I and j, respectively a condition I displacement under constraints of practical value to the maximum allowable value.
At the same time, must also meet the j structure under a power differential equation
M j, c j in j, k, j, respectively structure under a matrix, damping and stiffness matrix of corresponding quality.
For this non-linear programming problem, design the optimal value of a variable and depends on the structure of the corresponding control design elements of a (including m, c, k, frel, etc), as a basis for optimization design of control gain.
4 System design of radar antenna control system
Control system design in structure is the purpose of the given premise controlsystemdesigned to meet the performance requirements. Under normal circumstances,requires that the system has a stable, fast, accurate performance, the design of controller should be on the premise of ensuring stability, achieving fast, accurate tracking. To this end, the introduction of optimization design method for control, that is, to optimization design of the controller gain p, servo track system with excellent performance, and b at the same time are dependent on the structure design of control elements (such as drivers). So the problem can be described as a nonlinear programming problem (Figure 2).
Figure 2 radar antenna servo system design of optimal control gain
Solution
In the PI as I gain control variable, N6 to gain total number of design variables. To minimize the objective function accumulate tracking errors j, j reflects on the track "fast" and "quasi" requirements
Type, T0 is a motor cycle, e (t) for tracking errors.
Constraints include the regulation stability constraints, time constraints,overshootand torque constraints
Polei for System I, N7 is the total number of Poles, TS to adjust time, overshoot, f (t) to the controller in the field of driving force or torque.
5 Radar antenna servo system of integrated design of structure and control
Radar servo system for high performance, even if separately for optimum design of structure and control for, often still do not meet the requirements of performance indicators, because this method does not guarantee that the overall design of servo system is optimal. Possible results are based on structure optimum design results of control design, solution of limited access to meet performance targets, or are b and contradicts the structure optimization design of design elements. To this end, there is a need for integrated optimization design of structure and control, optimization of structure and control together. Specifically, that is, for a given structure parameters of control parameter a and u, found by seeking optimal comprehensive index of h p d and control gain optimal structure design variable values. So problems can be described as a nonlinear programming problem (Figure 3).
General design issues to minimize structural objectives constitute an optimal design problems. Because the control force (torque) is to control the gain function of p, so the average control can also be described as a general gain problem usually gain problem with minimized optimal gain control objectives constitute a problem. On the optimal design and optimal gain issues are coupled to each other, that for optimal design problems can be dependent on the structure of the design elements of a control (including m, c, k, frel, etc), as based on the optimal gain and optimal gain problem solving can be dependent on structure design of control elements.
6 Numerical simulation and experiment
To verify the feasibility and effectiveness of the methods mentioned in this article, apply it to the following 3 example, made satisfactory results. Given the limited space, the 1th and the 3rd example are numerical test results only, and the 2nd one is both a numerical and physical verification.
Example 1-reflector antenna with slider-crank mechanism (Figure 4). Crank-slider mechanism, as shown in Figure 4, m control torque applied to crank on OA, select a location to install the antenna on the connecting rod AB, corresponding to point to. Purpose and is controlled by adjusting the torque structure design, antenna tracking goals. Changes range from 10 ° from the angle of ~80 °.
Figure 4 crank reflector antenna
Crank and connecting rods are hollow tubes, R1 and R2, respectively in the cross section of the crank and connecting rod diameter, δ, δ b, respectively wall thickness. PID controller for proportional, integral and differential gain parameter P1, P2, P3, respectively. In dynamic modeling, crank for rigid body, connecting rod for elastomers, elastic deformation as the former ne-order vibration of simply-supported beam stack, take this example ne=3.
Design integration and separation of the results as shown in table 1. Figures 5 and 6 respectively 0.2 s before responding and comparison of driving torque curve, because 0.2 s later there's little difference. Visible results to be significantly better than separation of the integrated design optimization results, such as reduced adjustment time TS by 13.5% (0.074 s down to 0.064 s), natural frequency f RE1 improves 58.12% (11.52 Hz up to 18.2 Hz), total mass m down 30.57% (0.268 9 kg down to 0.186 7 kg).
Figure 5 integration, separation and design simulation comparison chart
Figure 6 integration and isolation design of driving torque comparison chart
Example 2: a servo test-bed system (Figure 7). Considering servo systems made up of gear reducer, set equivalent to the moment of inertia of the motor shaft, J1, J2 and J3, respectively, the torsional rigidity of the shaft respectively as K1, K2, damping coefficient for B1, B2,3 bearing friction factors are 1, 2, and 3.
Load and motor has been established, overall geometry parameter limits, motor shaft and bearing axle wheelbase has been fixed, the digital PID controller using the traditional control. Requires the design of the structure parameters (including load axis radius r, length l, drive shaft radius r, I, PID control gain reduction ratio P1, P2 and P3), cause the system to meet the demands of performance indicators (under the unit step response overshoot ≤ 2%, adjusting time TS ≤ 0.3 s) has provided the overall best performance.
Using the same initial values (initial design of servo test-bed), separate isolation design and integrated design, and sequential quadratic programming method for solving, results are shown in table 2, the unit step response of the system as shown in Figure 8.
Figure 8 the unit step response of the system diagram
To illustrate the correctness of results, under the initial physical validated numerical results on the test bench. Figure 9 to the initial design, measuring the unit step response and comparison of simulation results. Because of not considering dynamic characteristics of motor and servo amplifiers and manufacturing precision, experimental results and simulation results there is a difference (the maximum error is less than 5%). It is to be noted that, to optimize the results of tests shall be special made to order gears, shafts, as well as the corresponding structure, is not very realistic. However, under the initial description of the test the accuracy of the model.
Figure 9 Unit step response of the system (initial design) simulation and experiment of curve
Example 3: a 40 m antenna servo system (Figure 10). The 40 m antenna pedestal azimuth rotation system as shown in Figure 10. By supporting the installation of antenna on the fork arm. Direction of servo motor drive torque gearbox, drive shaft and the ring gear on the turn table, so as to drive the antenna azimuth rotation. Antenna weight to 65 t, its track in 30 ' precision '. Reduction ratio of the assumed position Rotary system, structure and the external dimension of the fork arm (including fork arm length in the section long La, w WA, Lb, cavity width WB) and table structures has been fixed. Purpose is controlled by adjusting the torque of the optimized design and structural design, the antenna tracking performance improvement, azimuth rotation system of reduced quality. Structural design variables include: upper and lower arm of box-shaped structure of the outer ring wall thickness δ a, upper and lower arm of box-shaped structure of inner wall thickness δ b, wall thickness δ c of table structure, antenna supporting wall thickness δ d, drive shaft radius r; for PID control design variable gain coefficient (P1, P2 and P3).
In optimization, take the m-max 18 kN m, TS 2.0 s, Max 2%, f RE1 5 Hz, 30 MPa, results such as shown in table 3. Table 3 comparison for the corresponding parameter. Table 3: integrated optimization design, reduced the time TS 14.3% (1.890 s to 1.620 s), natural frequency f RE1 improves 22.42% (6.870 Hz to 8.407 Hz), reduced the cumulative tracking error 16.12% (from 0.003 to 0.002), total mass m increases 0.42% (from 77.905 t to 78.239 t). Visible, said on the whole, results than isolation design of integrated design results.
Numerical simulation and physical verification of the above descriptions, separation of structure and control design is hard to even get the best overall performance, integrated design can be an effective solution to this problem. Integrated design especially suitable for servo-system design.
7 Conclusion
(1) presented a radar antenna servo system of an integrated design model, at the light quality of the structure and control of stable, accurate and fast target, solved the design brought about by the separation of the two in the past have too many things to take care of at the same time, it's hard to even get the overall performance of the system the best question.
(2) study on Nonlinear characteristics of integrated design model, and thus gives the solution to some of the strategies and methods, numerical simulation results, describes the feasibility and effectiveness of the models and methods. But if the agency model is more complex, more design variables, using this method of modeling to solve can be difficult.
(3) to further verify this article's correctness and validity of models, methods and software, a practical servo test rig, physical verification, good results. To make the test results more convincing, should be taken into account in the work of the following, for discrete variable optimization design, that is, on the test bench the given parameters within the scope of a variable, because often only the scope of the change is limited and discrete choices. (4) models and methods proposed in this article, the other servo system design also has a certain reference and reference value.
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