Computer search of variants for vehicle system composition synthesis

The design experience of vehicles systems composition synthesis is summerized. Some engineering techniques are suggested, which give an opportunity to solve the problems of a composition synthesis by means of a computer. These techniques are based on the following principles: construction of statistical models for the analysis of criteria behaviour; using of methods of the theory of extreme values statistics for the evaluation of the criteria limiting values; deriving of suboptimum variants groups; using of heuristic procedures for a cyclic correction of the search process in order to specify the range of boundary solutions for the problems with several criteria; using of a probabilistic appraisal for an estimation of search results; construction of educating algorithms using a fine for the variable values (composition variants); clearing up in the course of a dialogue process the interaction of an engineer with a computer.As in the design practice no requirements are extended to the algorithms of vehicle system characteristics design, that is why it is not possible at the stage of design solutions search to use the known recommendations worked out for the problems of linear, non-linear and dynamic programming.     

Algorithms for the transport spacecraft descending stage lateral motion control

This report deals with the problems of synthesizing algorithms for controlling the attitude manoeuver of a transport spacecraft aimed at injecting the spacecraft into a closed terminal domain of “heading-range” phase coordinates which makes it possible to descend to the landing aerodrome region in accordance with a spiral trajectory tracking pattern. The descent trajectory is controlled by changing the roll angle. The principal distinguishing feature of the suggested method of transport spacecraft lateral motion control resides in guiding the spacecraft to a terminal curve and in providing an automatic transfer from roll control to interacting control of roll angle and angle of attack. The performance of the control algorithm under transient conditions are considered in detail.Algorithms controlling the longitudinal range by varing the magnitude of the roll angle and lateral range by selecting the respective sign of the roll control angle are thereafter synthesized separately. The major problem in designing the angular motion control system of transport spacecraft is the development of a high-rate roll axis turn control algorithm. To ensure high accuracy of lateral manoeuvering of the spacecraft it is expedient to accomplish the spacecraft reorientation in roll in a minimum time. It is therewith necessary to take into account with the sideslip angle limitation associated with the need of complying the design conditions of the spacecraft flowaround and with the spacecraft skin selected temperature conditions. It is expected that the total side slip angle is acceptable for measurement. Within the greater portion of the descent trajectory constant-thrust jet-reaction control engines are employed as actuators. Therefore, together with the high speed of response developed control algorithm provides an adequate efficiency of the system from the viewpoint of fuel consumption. The possibilities offered by the suggested algorithms controlling the lateral motions of the center of masses and around the center of masses during the descent stage and in the course of landing approach manoeuvering are illustrated by an example considering a hypothetical transport spacecraft featuring variable aerodynamics and a low frequency of natural oscillations of the angular motion loop. The suggested algorithms make it possible to fully employ the transport spacecraft maneuverability and to meet the terminal heading and velocity requirements within a wide class of disturbances.     

Informational approaches to angular motion control of spacecraft

Any information concepts may be used for motion control with respect to the center of masses of a reusable transport spacecraft (RTS). Using comparative analysis of the two concepts (the first one, based upon information about attitude parameters with respect to the inertial reference system and the second one, based upon parameters of angular motion with respect to wind-body coordinate system) for specific features of RTS dynamics and control at the stages of orbital flight, atmospheric flight under gas dynamic and aerodynamic control, and landing, paper demonstrates that information on angles of attack, slip and speed roll should be used for angular motion control at this stage of flight.     

Study of automatic and manual control problems of spaceplane atmospheric flight under simulated g-load effect

The descent in the atmosphere belongs to the most complicated phase of flight and presents stringent requirements for spaceplane systems. The enhanced requirements for reliability, the necessity of aircraft-type landing and a number of other reasons lead to the necessity of maximum involvement of the crew by means of creating, along with fully automatic, manual and director control systems and providing the crew with the possibility to monitor the systems operation and to actively override them. Participation of man in performance of such tasks during the atmospheric descent is hampered by a number of major difficulties caused by alteration of his state under the g-load effect.To evaluate the utmost capabilities of the manual and director control systems and to make rational selection of indication systems and controls it is necessary to create special flight simulation complexes comprising a hybrid computer complex capable of simulating vehicle trajectory and angular motions and the computer complex controlled centrifuge equipped with a crew-cabin, which would allow real-time simulation of the g-load effect upon the crew.This paper describes the structure of such complex, the distribution of tasks between the analog and digital computers and presents some results from evaluation of manual and director control system characteristics.     

基于TestBed 和Visual Studio 对QT 程序单元 测试的研究与实现

针对测试工具TestBed 无法动态执行QT 程序单元测试用例的问题，文章通过介绍单元测试定义、测 试原理以及TestBed 工具的使用原理、并指出了TestBed 工具对QT 程序进行单元测试存在的问题，最终提出 了一种结合TestBed 和Visual Studio 对QT 程序进行单元测试的方法，并给出了方法的详细设计与实现步骤， 为QT 程序动态执行单元测试提供一种简单、便捷的实现方式。实际结果表明，结合TestBed 与Visual Studio 对QT 程序的单元测试方法显著提高了单元测试的效率，减少了单元测试的成本。