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To meet the test requirements of the key structural part in the super high-rise building, a 108MN 6-dof advanced structural testing system is developed. And for the high-speed shear test of the large rubber bearing, the instantaneous flow demand of the testing system is far more than the conventional hydraulic testing equipment. For this, the piston accumulator group with the separated nitrogen cylinder is adopted as the system auxiliary hydraulic power. In the paper, the optimization design of the accumulator group is implemented though continuously optimizing the volume ratio of the accumulator and the nitrogen cylinder. And when the accumulator group works, its pressure decreases from the precharge pressure to the working pressure constantly, which will impact the loading accuracy, and the excessive pressure is also not conducive to the protection for the specimen. To restrain the pressure fluctuation, a pressure control loop with the large-flow cartridge valve is presented, the associated model is set up and the control method is developed. The results show that with PD control the oil supply pressure of the accumulator group can be stabilized within the required range, and the control precision is high.

Ni–TiC composite coatings were prepared on substrate of aluminum alloy by pulse electrodeposition. The plating parameters for optimizing wear and corrosion resistance of Ni–TiC composite coatings were selected by orthogonal test, including the TiC particles concentration, current density, duty cycle, frequency and stirring rate. A three-layer back propagation (BP) artificial neural network with Lavenberg–Marquardt algorithm was established by MATLAB, which was used to train the network and predict orthogonal experimental data. Additionally, the best combination of parameters of the composite coatings were predicted and verified by experiments. The wear and corrosion resistance of Ni–TiC coatings were characterized and analyzed. The results indicated that the BP mode, which shows a relative error of approximately 3 %, could effectively predict the wear and corrosion resistance of Ni–TiC composite coatings. Ni–TiC composite coatings deposited by optimal synthetic condition showed dispersed TiC particles and continuous Ni matrix, as well as excellent wear and corrosion resistance.

The plating parameters for optimizing the wear and corrosion resistance of Ni-TiC composite coatings were selected by orthogonal test, mainly including the TiC particles concentration, current density, duty cycle, frequency and stirring rate. A three-layer BP (Back Propagation) neural network with Lavenberg-Marquardt algorithm was established by MATLAB, which was used to train the network and predicted orthogonal experimental data. In addition, the best parameters combination of the composite coating were predicted and verified by experiments. The results predicted through the proposed BP model are in good agreement with the experimental values, the relative error is small, and the maximum error is less than 3% and the coefficient of determination value is 0.9997.

This article presents a high fidelity acceleration time waveform replication (TWR) on an electro-hydraulic shaking table (EHST) using the hybrid control combined with an offline feed-forward compensator and an online adaptive inverse control (AIC). This study applies the acceleration and velocity feedback to improve the steady performance of the EHST, and employs the system inverse transfer function (ITF) of the acceleration closed-loop system to extend the frequency bandwidth and a modeling error compensator to improve the dynamic characteristics. Moreover, the investigation utilizes a Zero Phase Error Tracking Controller to improve the accuracy of the designed ITF. The proposed hybrid controller also utilizes an online AIC for a high fidelity TWR after that the dynamic characteristics has been improved by the feedback and feed-forward controllers. Thus, the proposed hybrid control strategy combines the merits of the offline feed-forward compensation and online AIC. Performance analysis and comparison of the experimental results demonstrate that better replication accuracy with the proposed hybrid control can be achieved in experiments on an actual EHST.

An electro-hydraulic shaking table which is based on acceleration control is studied here. A three-variable control scheme is applied to achieve robustness, disturbance suppression and sufficient frequency bandwidth. Its acceleration response contains harmonics corresponding to sinusoidal input because of nonlinearities in the system. To reduce harmonic distortion and improve control performance of the shaking table, a harmonic cancellation algorithm is developed. The weights of the proposed algorithm are on-line updated by the normalized LMS algorithm. The reference input with input frequency is filtered by the adaptive LMS filter. The output of the adaptive filter is a close harmonic replica and is added to the fundamental signal such that the output harmonic is cancelled leaving the desired signal alone, and the total harmonic distortion is greatly reduced. Experimental results demonstrate the efficiency and validity of the proposed control scheme.

Trimming aircraft on the ground is an absolutely necessary for flight simulators. In order to carry out this task, the aircraft-runway dynamic model is analyzed, and then an elite re-optimized hybrid genetic algorithm for trimming the model is designed, which combines the merits of a genetic algorithm and pattern search. It does not only avoid being trapped by a local optimum, but also improves the precision of results and saves on the time for trimming. Because this trim method requires only in-out information of the dynamic model, it is a universal tool and can be used on different trim works of different simulated aircraft. Its efficiency is then validated in a flight simulator, which reveals its engineering significance.

The model based on Internal Force Space to reduce the internal force of super-redundant actuated parallel mechanism is put forward in this paper. The model is proposed to restrain the internal force in the redundant actuated parallel mechanism especially in super-redundant actuated parallel mechanism(SRPM) with long stroke, such as the Million Tons Tester's (MTT) horizontal redundant driving mechanism. It study a method to work out the internal force of redundant actuated parallel mechanism by using the result of the actuators' force vector and the Internal Force Space basis. Using the internal force as the feedback to regulate the servo values' control signals is proposed in this paper to reduce the redundant actuated parallel mechanism's internal force. Compared to traditional pressure stabilizing controller the model based on Internal Force Space has a better effect in reducing the internal force. At last, the joint simulation with MATLAB and ADAMS is built to test the model.

Physicochemical Problems of Mineral Processing; ISSN 2083-3989

Considering the characteristics of fire in the cabin of Civil Aviation, a new method is introduced to do the fire simulation by using computer simulation. Some basic theories, computational models and practical problems are given about the fire dynamics simulation software FDS and evacuation software Evac. Finally, an example of cabin fire is used to explain how to employ the software and apply the results to the practical evacuation and rescue of cabin fire. Keywordscabin fire; fire simulation; human evacuation; FDS;Evac

For the purpose of acquiring the immersion and reality of flight simulation, there is a necessity to reproduce 3D sound field of aircraft cockpit. In this paper, a 3D sound simulation system which is integrated into flight simulator used for training pilots is developed. After determining the sound events which will be simulated in flight simulation, spectrum analysis and time-frequency analysis are used to analyze original recordings for finding out the sound features of each part of an aircraft. And then sound sources which will be used in simulation can be extracted by using LMS adaptive filtering and other basic signal processing methods. Based on system integration and performance consideration, a new component of sound simulation system is presented and the object-oriented software development is used to develop the software part for matching this component. Two key technologies are particularly discussed in software realization: real-time sound synthesis and sound spatialization. The 3D sound simulation system meets development requirements after many flight tests and works reliably in a Boeing 737-800 flight simulator which is developed in our lab.

This paper proposes a modal space decoupling controller for the highly coupled six degrees of freedom parallel robot. It is based on singular value decomposition to the properties of the joint space inverse mass matrix, using an orthogonal unitary matrix. The method moreover, maps the control and feedback variables from the joint space to the decoupled modal space. Using this method, the highly coupled six-input-six-output dynamics of the parallel robot was transformed into six independent single inputs, single output one degree of freedom hydraulically driven mechanical system. The simulation result shows that the controller improved the trajectory performance more than the conventional PID controller in all DOF and eliminated the dynamic coupling effects.

Adaptive Inverse Control(AIC) based on Recursive Least Square(RLS) is applied in Control Loading System(CLS) of Flight Simulator(FS) .The algorithm was used to improve position tracking accuracy as an inner loop of CLS. This paper presents the implementation of a rapid prototyping control system based on RAT-LAB simulation environment, which involves the design of AIC and RLS algorithms using MATLAB/Simulink blocksets. The effectiveness of AIC was verified by mean of the analysis of the experiment results such as the comparison of reference signal and position output response signal, the change of frequency bandwidth. Finally, the accuracy of identification was pointed out via experiment that is a critical factor of the AIC.

with continuing improvement in hardware and software, flight simulator plays an expanding and important role in the training of aircraft crews, design of new aircraft, entertainment and Human-Machine Interaction. With the development of China large commercial aircraft, flight simulator can be used to research cabin equipment arrangement to fulfill human-machine interaction comfortable requirement and aircraft performance evaluation. Based on the background, a fixed-based reconfigurable flight simulator was developed. In order to reduce development cost and software development time consuming and debugging difficulty greatly, Commercial-Off-The-Shelf software and Rapid Prototyping technology were adopted. This paper shows you the development process and the research application.

A novel method, modified particle swarm optimization algorithm, is proposed to compute flight envelope in this paper. According to the principle of thrust method, the problem of solving flight envelope is converted into searching the optimal solution by the particle swarm optimization algorithm (PSO). Combined with adaptive inertia weight factor, the standard PSO algorithm is modified. Applying the modified PSO algorithm, the flight envelope is solved. Numerical simulations results illustrate that the search algorithm is feasible and efficient for solving flight envelop.

In order to investigate and exploit advanced flight management system with complete functions, provide applicable and reliable performance data for optimal trajectory search, data structure requirements of performance database of flight management system are presented, including the structure of aerodynamic data ,engine performance data and operation data. The whole authentic performance data is acquired by integrating the performance data of flight simulator in the second phase of 985 projects and the flight manual. Based on the former performance data, combining the thrust method, particle swarm optimization algorithm and the energy-state method, the performance data is transferred into equal energy-height curves which can be more applicable for optimal trajectory search. Based on the processed performance data, the performance model is built on the basis of Microsoft Visual C++ and MATLAB/SIMULINK. The running results of the flight management system program indicate the method used to exploit performance database of flight simulator prototype system is effective and feasible.

A realistic 3D sound simulation system which is integrated in a flight simulator used for training of pilots is developed. The components of a flight simulator are introduced briefly. To meet the requirements of sound simulation system, Visual C++ and DirectSound API are selected as development software. We discuss the design and implementation of a sound simulation system by using DirectSound. The key technologies in development which include sound source analysis and sound spatialization are analyzed. Sound spatialization (3D sound) technology is especially discussed and is solved by using DirectSound 3D in development. The 3D sound simulation system meets all development requirements and works reliably in a Boeing 737-800 flight simulator which is developed in our lab.

A 3-dof rotational parallel mechanism is presented which has three struts and three actuators and is a plasmodium of the Stewart platforms. The kinematics of this robot is derived, and the kinematics analysis is investigated based on analytical solution of the inverse kinematics and numerical solution of the forward kinematics. This mechanism is popular in the fields of simulators and parallel kinematics machines.

Flight simulator is a large-scale simulation system. Because of the limitation by computer powers, only special computers ever were used to realize flight dynamics simulation and image generation in full flight simulator in the past. With the development of computer powers, high-performance computation and simulation can be realized applying by PC. While the need to reduce costs in every aspects of flight simulator become very important. A PC-based prototype system was implemented according to the architecture of flight simulator featuring a generic double engine airplane. Commercial-off-the-shelf (COTS) software components were use to reduce costs and improve developing efficiency. The detailed process was proposed. The integrated system shows that the feasibility of design based on PC.

Three axes hydraulic shaking system as the means to recreate vibration environment can accurately reproduce reference power spectrum density and time history response. The vibration control is a key technique to meet the requirement. This paper introduces the principle of the three-axis six-DOF shaking table at first and then designs hardware system using TMS320C2812 to acquire the analog and digital variable and using TMS320C6713 to operate and communicate with S3C2410 via dual-RAM in order to improve real-time and rapidity of the system. In the end, this paper presents the implementation of a rapid prototyping control system, which involves the design of DSP algorithms using MATLAB Simulink blocksets, automated code generation in the CCS integrated development environment, and downloading of executable code to the Texas Instrumentspsila TMS320C2812 and TMS320C6713.

This paper presents the theoretical development of a revised optimal control pilot model (ROCM) based the modified optimal control model (MOCM) of human operator developed by Davidson and Schmidt. An algorithm designed for easy implantation in current computer simulation and simulator fidelity analysis is presented. Example results based upon the analysis of a tracking task using a basic dynamics system is compared with the results of the ROCM and the results of the MOCM. The pilot frequency responses and root mean square obtained with the ROM are shown to more favorably to the measured experimental results than the MOCM in the pilot's frequency range of interest. The ROCM is not only consonant with the appropriate physical essence of the pilot, but also possess' the advantages of the MOCM.

The purpose of this paper is to develop an approach to improve the tracking characteristics of a small-scale shaking table actuation system, which is used in active structural control system. In this paper, firstly, the active control experimental system is described in detail. Then, the process of constructing analytical model of servo-hydraulic actuation system is presented. The proposed model, in the form of the total shaking table transfer function, accounts for the specific physical characteristics of the small-scale shaking table. Due to low natural frequency and small hydraulic actuator damping, the small-scale shaking table cannot meet the experimental requirement. Thus, three states feedback and three state feedforward control algorithm based on pole-assignment principle is applied for extending the acceleration bandwidth and improving system damping. Lastly, the shaking table experiments are tested and the experimental results indicate that the controller is effective.

Control loading system is one of the important components for a flight simulator. It provides fidelity force simulation to pilot and belongs to passive force control system. According to the flight control system's principle of boeing737-300, this paper gives the simulation principle in flight simulator. Three channels Primary Control Loading system (PCL) hydraulic driven actuators were developed. The mathematical model was derived for the PCL. By means of rapid control prototyping technology, the passive force control system based on industrial personal computer is developed. Experiments demonstrate that the system has less than 4% error between computed force and actual force and good tracking performance. The PCL has been applied to flight simulator prototype system.

Traditional design of 3-DOF parallel kinematic manipulator is a serial design, in which physical prototype based design and verification bring about restrictions to the development period and efficiency. In order to realize rapidly and efficiently from the conceptual design step to prototyping step, it's proposed to combine VR with kinematics analysis, structure design and kinetic analysis to develop a visual design environment (VDE). Based on visualization of kinematic solutions the analysis results can fully account for kinematic behavior of the real machine. Moreover, the verification based on kinetic mode makes sure the design reasonable and reliable. Compared with traditional design our developed routines are very effective. In this paper the implementation is described in detail