Design And Realization Of Monitor Software In The Depth Simulator

The depth simulator is an important facility for the control simulation system of underwater vehicle. Different water pressure exerted on the underwater vehicle could be simulated using this equipment when the vehicle sailed in the sea. Coordinated with the relative modules of the underwater vehicle system, different parameters and performance controlled by the depth control system could be tested directly in vertical direction under the laboratory condition.On one hand, restricted by the precision and range of the pressure sensor, the measure range and measure precision of the traditional depth simulator were very limited. On the other hand, affected by the designers' experience, the conventional proportion-integral-differential algorithm used in the simulator was very onerous and time-consuming. Even so, it was still difficult to get the expected result.In this paper, an new depth simulation solution was put forward , which was digitally controlled and could feed back from double pressure sensors. This solution was based on the related intelligent control theory which has developed rapidly in recent years. By using the method of real-time control and object-oriented design, the depth control algorithm was studied and the important digital control part - monitor software in the depth simulator was designed in this research. Controlled by the monitor software, the depth simulator could simulate the different water pressure precisely when the underwater vehicle was sailing, so the requirements including the items of large depth, high precision simulation, real-time display could be realized.The content and result of the design in this paper was as follows:1) Design of digital controllerBecause non-linear nature Exists in controlled objects and control parameters are not certain in depth controller, general proportion-integral-differential (PID) algorithm can not achieve the expected results. So in this paper, combining the theory of intelligent control with the general PID algorithm, and using digital control method which can adjust control structure and parameters flexibly, a new nonlinear intelligent proportion-integral-differential controller was designed. According to the cases of system response deviations from setting depth and the directions of deviations, the intelligent PID control algorithm can adjust control parameters automatically to enhance or weaken control ability in virtue of related control rules. So the designed simulator could output depth which approaches to the setting value quickly and calmly. Simulation results showed that: this solution decreased the depth following error which was lower than 0.05 meter, and enhanced the adaptability of non-linear factors. The dynamic quality of simulator system was also improved greatly.2) Study of a control method of real-time, large depth, high precisionBy remaking the single scale pressure sensor into two different scale pressure sensors, the system could feed back the depth in different scale range. Between the transition regions, the smooth transforming algorithm and data fitting were used to realize the required large scale, high precision depth simulation. The system experiment showed that: the measuring depth range was from 0 to 655.35 meter, the resolving power reached 0.01 meter, and the precision in static state was to 0.1% .In order to realize real-time control, a running mode was developed, which combined the single task mode in multiple rates with multiple tasks mode in multiple rates. This new mode improved the design efficiency of real-time system greatly. To dispatch multiple tasks, an algorithm of adjusting priority dynamically and the tactic of dispatching tasks flexibly were used. In this way, the dead-lock phenomenon could be lessened, the rate of system resource utility was increased. Simulating experimental results showed that by applying this running mode, the minimum system update period could reach to 0.001 second. So, the requirements of real-time, multiple tasks processed simultaneously in the underwater vehicle system could be satisfied.3) The design and realization of remote controlling simulationThe remote communication mode is one of the important control modes of depth simulator which was used to realize depth simulation control from the upward simulating computer to the downward depth simulator. In this paper, a serial asynchronous communication mode was adopted to fulfill remote control. Compared with synchronous communication mode, this asynchronous mode could transmit data much further and simpler. During the software design, safe data class was selected to assure data safety. Windows API time function was called to gain accurate control time. The communication experimental results showed that by this method the interval communication time could be given to 0.001 second, and the data was transmitted correctly.4) The design and realization of monitor interfaceA graphic interface of monitor software in Visual C++ was established for users. It could set simulation mode and pressure range, execute simulating control, display depth chart precisely, self-test and provide help service.5) The design of software reliabilityIn order to avoid program skip running, datum lost and to enhance the ability of software disturb-resistance, software filter, watch-dog technique and others were used so as to assure software running reliably.The software test and system simulation results showed that this monitor software could reach the design target of depth simulator. The monitor interface was concise and could be operated conveniently. The result of depth simulating was good. By far, this monitor software system has been applied to the simulation of the underwater vehicle formally.