Semi-physical Simulation Experiment Research Articles

A Novel Optimal Layout Method of Airborne Distributed POS Based on MAC and GMC Hybrid Optimization Criterion

The layout of the airborne distributed position and orientation system (POS) directly affects the overall accuracy of the motion parameters of all load points obtained by the distributed POS. However, there are restrictions of space, weight and cost of the distributed POS, it is unrealistic to install an inertial measurement unit (IMU) at the location of each load. To solve this problem, based on modal analysis of wing structure, considering the two factors of the modal spatial intersection angle and the vibration amplitude, a novel fitness function model based on modal assurance criterion (MAC) and Gramian matrix criterion (GMC) is proposed to evaluate the population in the optimization algorithm. The hybrid adaptive particle swarm optimization and genetic algorithm (HAPSOGA) based on this proposed model is applied to the multiple system layout of airborne distributed POS to obtain the optimal layout scheme. The results of semi-physical simulation and ground verification experiment show that compared with the optimal method based on MAC, the optimal layout scheme determined by the proposed method can use less IMU and obtain higher overall accuracy of motion parameters for the remote sensing loads.

Research on Measurement Method of Parachute Scanning Platform Based on MEMS Device.

This paper studies the measurement of motion parameters of a parachute scanning platform. The movement of a parachute scanning platform has fast rotational velocity and a complex attitude. Therefore, traditional measurement methods cannot measure the motion parameters accurately, and thus fail to satisfy the requirements for the measurement of parachute scanning platform motion parameters. In order to solve these problems, a method for measuring the motion parameters of a parachute scanning platform based on a combination of magnetic and inertial sensors is proposed in this paper. First, scanning motion characteristics of a parachute-terminal-sensitive projectile are analyzed. Next, a high-precision parachute scanning platform attitude measurement device is designed to obtain the data of magnetic and inertial sensors. Then the extended Kalman filter is used to filter and observe errors. The scanning angle, the scanning angle velocity, the falling velocity, and the 2D scanning attitude are obtained. Finally, the accuracy and feasibility of the algorithm are analyzed and validated by MATLAB simulation, semi-physical simulation, and airdrop experiments. The presented research results can provide helpful references for the design and analysis of parachute scanning platforms, which can reduce development time and cost.

Ground semi-physical simulation experiment study of one-dimensional drag-free control

Drag-free control is one of the key technologies for the verification of Taiji-1 satellite. In the direction of sensitive axis, the drag-free controller receives the measurement signal from the high-precision gravitational reference sensor on the satellite, and instructs the micro-thruster system to counteract the disturbance force acting on the sensitive axis, so that the microgravity level in the sensing axis direction of the satellite can reach the order of 10[Formula: see text] m/s2 in the measurement band. In order to fully verify the drag-free control system, a ground one-dimensional drag-free semi-physical simulation system is built to simulate the performance of various payloads in the drag-free control loop, and to verify the performance and technical targets that the drag-free control system can achieve in the ground control loop. Through the small angle approximation, the equivalent relationship between the rotation of the experimental model and the translational motion of the experimental satellite in the direction of drag-free is demonstrated. In the condition of neglecting the stiffness and damping of the suspended pendulum, the parameters of the suspended pendulum are designed according to the principle of equal acceleration, and their effectiveness is verified by numerical simulation. According to the operation mode of on orbit drag-free control, the ground drag-free experimental scheme and drag-free controller are designed, and the experimental research and verification are carried out. The results show that the controller can effectively control the displacement and acceleration of the experimental model, and also can effectively suppress the disturbance of certain amplitude and frequency.

Integrated modeling of motion decoupling and flexure deformation of carrier in transfer alignment

In airborne distributed inertial measurement system, there are complex working environment and obvious structural deformation regards to the carrier, which make the research of transfer alignment technology more complicated. Considering the influence of dynamic deflection and coupled motion, the integrated transfer alignment model of decoupled and flexed deformation is established in the paper, which is based on the requirement of high precision navigation information at the sub antenna of airborne earth observation system. On the one hand, combined with Fiber Bragg Grating (FBG) sensor to measure the deflection of the aircraft wing, a general deflection model of the aircraft wing is established, and the accuracy of the model is verified by finite element analysis. On the other hand, the traditional airborne transfer alignment regards the motion of the carrier and the dynamic deformation of the carrier as uncorrelated motion, but there is a strong coupling between them in practice. In the paper, based on the geometric relationship between them, the coupling is solved, and the system error equation is updated. The feasibility and accuracy of the proposed transfer alignment model are verified by semi physical simulation experiments. The results show that the proposed model is faster and more accurate than the traditional transfer alignment model.

Research On Active Power Online Optimal Control for Hydrostatic Transmission Wind Turbine

Wind has been admitted as one of the most promising renewable energy resources in multinational regionalization policies. However, due to the randomness and volatility of wind energy and the rigid transmission of traditional wind turbines, it is difficult to control the active power of wind turbines with high precision. Thus the hydraulic wind turbines (HWT) is taken as the research object, and the stable operation of wind turbines at a demand power point under certain wind speed conditions is realized. The mathematical model of HWTs is established, and the HWT operation characteristics are analyzed. The small signal linearization method is adopted to solve the multiplying nonlinear problems in the system, and the working area of the power transmission system to adjust the transmission power stably is analyzed. According to the demand of active power control for wind turbine, the HWT active power control strategy is proposed. However, the power response of the HWT is inconsistent with the time-varying operating point and the proposed controller fixed parameters. The controller parameter online adjustment method of system pressure and power gain is proposed. The effectiveness of the optimized control method is verified based on the semi-physical simulation experiment platform of HWT, and the consistency of active power response is achieved. At the same time, the power response characteristics are analyzed, and the HWT active power response time can satisfy the demand of electrical grid under the optimal control strategy.

A fusion strategy for reliable attitude measurement using MEMS gyroscope and camera during discontinuous vision observations

For indoor close-range high-accuracy attitude measurement using inertial and vision sensors, the major challenge is to achieve a reliable attitude in various scenarios, specifically in the absence of vision information. To address this challenge, we present a fusion strategy for reliable attitude measurement using a micro electro mechanical system (MEMS) gyroscope and camera, particularly during discontinuous vision observations. The proposed algorithm consecutively executes update and prediction modes. In the update mode, when both inertial and visual data are available, the complete Kalman Filter (KF) conducts the entire filtering process and updates residual and state errors. In the absence of visual data, the partial KF operates only when the time update and filtering state vectors are compensated by the transfer residual, which is estimated through self-propagating state error. The parameters of least-squares support vector machine (LSSVM-NARX) continuously update until the next discontinuous vision observation occurs, with the desired outputs and inner inputs being the error angles and the exogenous inputs being the gyroscope values and time. In the prediction mode, without visual data, LSSVM-NARX can provide estimated angle errors between the complete and partial KFs, which are used to eliminate errors from partial KF output vectors to obtain a reliable and accurate attitude solution. Comparisons and extensive semi-physical simulation experiments under various motion trajectories were performed to validate the effectiveness and superiority of the proposed scheme in an accurate and reliable attitude measurement capability associated with discontinuous observations.

Information Fusion Based on Complementary Filter for SINS/CNS/GPS Integrated Navigation System of Aerospace Plane.

In order to solve the problems of heavy computational load and poor real time of the information fusion method based on the federated Kalman filter (FKF), a novel information fusion method based on the complementary filter is proposed for strapdown inertial navigation (SINS)/celestial navigation system (CNS)/global positioning system (GPS) integrated navigation system of an aerospace plane. The complementary filters are designed to achieve the estimations of attitude, velocity, and position in the SINS/CNS/GPS integrated navigation system, respectively. The simulation results show that the proposed information fusion method can effectively realize SINS/CNS/GPS information fusion. Compared with FKF, the method based on complementary filter (CF) has the advantages of simplicity, small calculation, good real-time performance, good stability, no need for initial alignment, fast convergence, etc. Furthermore, the computational efficiency of CF is increased by 94.81%. Finally, the superiority of the proposed CF-based method is verified by both the semi-physical simulation and real-time system experiment.

The Inertial Integrated Navigation Algorithms in the Polar Region

Because the accuracy of the existing airborne navigation is lacking in the polar region, it is difficult to ensure the safety and reliability of the aircraft when it is flying over the polar region. The integrated navigation system based on the inertial navigation technology uses multi-information fusion to assist collaborative navigation and obtain an indirect grid navigation algorithm that combines the azimuth navigation algorithm and the grid navigation algorithm to solve the existing problems. This paper analyzes the principle of the inertial navigation system in the polar region, the semiphysical simulation experiments are carried out by using the navigation theory and the background engineering, and the accuracies of the integrated navigation system of the indirect grid frame in the polar region and the integrated navigation system in the middle and low latitudes are consistent, which verifies the feasibility and effectiveness of the SINS/CNS/GPS integrated navigation system in the polar region. In addition, the paper provides the theoretical basis and the application of engineering to achieve the SINS/CNS/GPS integrated navigation system in the polar region.

Cone Sleeve Center Measurement Algorithm based on Multi-information Integration

In order to meet the high-precision docking requirements of autonomous aerial refueling, this paper proposes a high-precision and fast positioning algorithm for the center of the cone sleeve based on two-dimensional and three-dimensional multi-information fusion. The algorithm performs target detection and tracking on the cone sleeve in the image after calibration and calibration, and adaptively selects the region of interest in the positioning area; the region of interest is calibrated based on the gray-scale constrained two-dimensional model and the three-dimensional model based on the depth gradient. The two-dimensional and three-dimensional information fusion result is back-projected and compensated to the region of interest to realize the high-precision center point position measurement of the center point. The algorithm is used in the semi-physical simulation experiment on the ABB mechanical arm to verify its feasibility, robustness, fast and high precision and other characteristics.

Acoustic target recognition algorithm based on particle swarm neural network

In order to improve the automatic recognition rate of acoustic targets, this paper conducts research on acoustic target recognition algorithms based on particle swarm neural network. Firstly, the mathematical description of the particle swarm optimization algorithm is described, and the initial parameters and algorithm flow of the particle swarm optimization algorithm in the experiments in this paper are given. Second, the design includes the central processor, power supply, signal conditioner, filter, trigger circuit, and state. Acoustic target recognition prototypes of display circuit, memory, target type indication circuit, serial port, crystal circuit, microphone and hardware interface circuit, etc. Finally, using the collected acoustic signals of tanks and helicopters, a semi-physical simulation experiment was designed to carry out target recognition. Experimental research and experimental results verify the effectiveness and stability of the acoustic target recognition system in this paper.

Kalman Filtering Algorithm for Integrated Navigation System in Unmanned Aerial Vehicle

Through the complementarity of the satellite navigation positioning system (GNSS) and the inertial navigation system (INS), the combination of GNSS/INS can make up for the shortcomings of a single system that is difficult to improve, thereby greatly improving the accuracy of the integrated navigation system. In this paper, the transformation relationship between the carrier coordinate system and the navigation coordinate system is deduced, and the INS position and velocity measurement methods are derived. Based on the theory of GNSS/INS loose combined system and Kalman combined filter, the system equation and measurement equation of combined filter Kalman are studied in depth. The principle of discrete Kalman filter is researched, and five basic equations of Kalman filter are given. Then the speed and position model of Kalman filter of GNSS/INS loose combined navigation is derived in detail, and according to the speed and position model perform semi-physical simulation experiments. The experimental results show that the inertial sensor can provide navigation information during the GNSS receiving signal gap, and the position and speed information of the GNSS can also correct the navigation information of the inertial sensor.

Improved Sliding Mode Control With Time Delay Estimation for Motion Tracking of Cell Puncture Mechanism

In this study, a cell puncture mechanism driven by a piezoelectric ceramic (PEA) is fabricated, and a novel precision robust motion controller is proposed to complete the cell puncture. A system dynamics model of the cell puncture mechanism is simplified by considering the hysteresis and disturbance as unknown terms to avoid the parameter identification of nonlinear dynamics in engineering applications. A sliding mode control (SMC) strategy with fast reaching law and proportional-integral- differential (PID)-type sliding surface, denoted as FPIDSMC, based on the simplified Bouc–Wen model is combined with time delay estimation (TDE) technology to form a novel controller, called FPID-TDE controller in this study. The stability of the controller is proven based on the Lyapunov theory. Computer simulation and semi-physical simulation experiments show the TDE technology can estimate and compensate accurately the unknown terms and does not require prior knowledge of unknown disturbance boundaries, thereby reducing controller gain. SMC can realize fast response speed, few steady-state errors, continuous output, and avoid chattering. Through a micropuncture experiment of a zebrafish embryo, the proposed FPID-TDE controller is shown to have high efficiency, high precision, and strong robustness. Therefore, the proposed FPID-TDE controller can be applied effectively to other micro nano-positioning systems driven by PEA.

Robust Method for Measuring the Position and Orientation of Drogue Based on Stereo Vision

The tracking and measurement methods of drogue in autonomous aerial refueling which based 2-D image, because of the loss of depth information, are susceptible to light changes, occlusion, etc., resulting in false tracking and the failure of position and orientation of drogue measurement, which may lead to collision of drones. In order to solve these problems, this article intends to introduce 3-D information to solve the position and orientation of drogue based on the original 2-D image tracking method. The method mainly includes two parts, tracking and measurement algorithms, using the decision function to effectively combine the two algorithms. The tracking algorithm provides a positioning area for the measurement algorithm, thereby reducing the amount of measurement operation data. The 3-D measurement result of the measurement algorithm based on stereo vision is used for measuring the drogue's position and orientation, and fed back to the tracking algorithm, which eliminates the candidate area and reduces the error rate to improve accuracy of the tracking algorithm. The measurement algorithm can still be realized stably high-precision under occlusion and no cooperation markers, which is not available in traditional 2-D image-based methods. We perform semiphysical simulation experiments to verify the effectiveness of the proposed method.

Research on Safety Technology for High-Speed Interruption for Mining Flameproof Movable Substation

Due to the working condition of low-voltage cabling from the mining flameproof movable substation to the loads of the mining face being poor, it is easy to cause various external mechanical damages to the cable sheaths. Furthermore, a single-phase earth leakage fault or short-circuit fault can occur when the low-voltage cable sheaths are damaged, and electric sparks caused by these faults can lead to a gas explosion. As the gas detonation time caused by the above faults is usually more than 5 ms, the high-speed interruption solid-state switch which controls the cables must cut off the current within 3 ms. This requires the action time of the solid-state switch to be less than 1 ms, and at the same time, the sampling and calculation time of the relay protection must be less than 2 ms. Based on these problems, this paper proposes the use of a high-speed solid-state circuit breaker (SSCB) topology at the neutral point of transformer, and analyzes the conduction mechanism and shut-off mechanism of the current of the SSCB. It presents an ultra-high-speed algorithm based on pattern recognition of single-phase earth leakage fault protection, and an ultra-high-speed algorithm of short-circuit fault which is based on the rate-of-change of the current. Finally, through computer simulation experiments and semi-physical simulation experiments, the feasibility of the above three technologies is verified to ensure that when a single-phase earth leakage fault or short-circuit fault occurs in the low-voltage cable, the solid-state switch which is installed in the mining flameproof movable substation will cut off the current within 3 ms.

Optimal Design and Analysis on High Overload Buffer Structure of Passive Semi-Strapdown Inertial Navigation System.

The isolation rolling platform inside a passive semi-strapdown inertial navigation system can isolate the high-speed rotation of a projectile via bearing to provide a low rotating speed environment for the angular rate sensors inside the platform in order to further improve the accuracy by reducing its measurement range. Aiming at the problem that the internal bearing cannot withstand high overload, an optimal design method for a high overload buffer structure based on point contact spherical cap structure is proposed. Changing the materials of the spherical caps can reduce the deformation of the two spherical caps during impact and reduce the pivoting friction; at the same time, the upper and lower spherical caps are both forced to separate by the spring force after the impact and to eliminate the influence of the pivoting friction torque that is generated by the contact of two spherical caps on the stability of the isolated rolling platform. By virtue of finite element analysis and ground semi-physical simulation experiments, the feasibility of the design is verified. The experiment results show that the design can play an effectively protective role in anti-high overload, and the maximum deformation radius of the optimized point contact spherical cap structure can be reduced by 40.8%; after the upper and lower spherical caps are separated, the isolation rolling platform’ capability of anti-high-speed rotation can be improved by 52% under the rotation speed of the main shaft at 10 r/s. In this way, the stability of the platform is improved, thus proving the value of the design method in engineering applications.

An improved magnetometer calibration and compensation method based on Levenberg–Marquardt algorithm for multi-rotor unmanned aerial vehicle

In order to improvethe yaw angle accuracy of multi-rotor unmanned aerial vehicle and meet the requirement of autonomous flight, a new calibration and compensation method for magnetometer based on Levenberg–Marquardt algorithm is proposed in this paper. A novel mathematical calibration model with clear physical meaning is established. “Hard iron” error and “Soft iron” error of magnetometer which affect the yaw accuracy of unmanned aerial vehicle are compensated. Initially, Levenberg–Marquardt algorithm is applied to the process of sphere fitting for the original magnetometer data; the optimal estimation of sphere radius and initial “Hard iron” error are obtained. Then, the ellipsoid fitting is performed, and the optimal estimation of “Hard iron” error and “Soft iron” error are obtained. Finally, the calibration parameters are used to compensate for the magnetometer’s output during unmanned aerial vehicle flight. Traditional ellipsoid fitting based on least squares algorithm is taken as reference to prove the effectiveness of the proposed algorithm. Semi-physical simulation experiment proves that the proposed magnetometer calibration method significantly enhances the accuracy of magnetometer. Static test shows that the yaw angle error is reduced from 1.2° to 0.4° when using the proposed calibration model to calibrate magnetometers. In dynamic tests, the sensor MTi’s output is used as reference. The data fusion of magnetometer compensated by the proposed new calibration model based on Levenberg–Marquardt algorithm can accurately track the desired attitude angle. Experimental results indicate that the accuracy of magnetometer in the yaw angle estimation has been greatly enhanced. In the process of attitude estimated, the compensation magnetometer data given by this new method have faster convergence speed, higher accuracy, and better performance than the compensation magnetometer data given by traditional ellipsoid fitting based on least squares algorithm.

Intelligent Fault-Tolerant Control System Design and Semi-Physical Simulation Validation of Aero-Engine

In order to improve the reliability and real-time of the control system of aero-engine, an intelligent fault-tolerant control system based on the online sequential extreme learning machine (OS-ELM) is proposed against the sensor faults. This system can realize the online fault diagnosis and signal reconstruction without a system model. And while considering the traditional PID control robustness and poor anti-interference ability and other shortcomings, an improved global fast non-singular terminal sliding mode control method is used to obtain better control effects, effectively solve the uncertainty problem in aero-engine, and give full play to aero-engine performance. To verify the feasibility and effectiveness of this system based on the above method, a turbofan engine is taken as the research object and semi-physical simulation experiments on fault-tolerant control are conducted on a semi-physical simulation test platform. Results show that the controller of this system can safely and reliably control the aero-engine without losing its control performance under the circumstance that there are faults in engine sensors. The purpose of fault-tolerant control is reached.

Research on Quasi-Synchronous Grid-Connected Control of Hydraulic Wind Turbine

The hydraulic wind turbine(HWT) is taken as the research object. To realize the quasi-synchronized safe connection of the HWT, the mathematical model of the fixed displacement pump - variable motor is first established, and the multiplicative nonlinearity existing in the modeling process is solved by the small signal linearization method. For the closed-loop speed regulation system of fixed displacement pump-variable motor, a variable speed input-constant speed output control method based on indirect flow feedback and direct-speed closed-loop system is proposed. Combining MATLAB/Simulink@ and a semi-physical simulation experiment platform of 30kVA HWT, the influence law of some parameters is analyzed for the response characteristics of the speed control system, such as the valve control cylinder response speed, the swash plate reference conversion value, initial swash plate angle and so on. At the same time, combined with the grid connection conditions for generators, a quasi-synchronized grid speed control method for HWT is proposed. Based on simulation and experimental methods, the instantaneous impact of grid connection is effectively suppressed.

Three-domain fuzzy wavelet broad learning system for tremor estimation

This paper proposes a new three-domain fuzzy wavelet broad learning system (TDFW-BLS) for tremor estimation in tele-operation. In the feature layer of our novel method, feature nodes can be mapped by a three-domain fuzzy wavelet sub-systems (3DFWs) and the k-means method is applied to determine the parameters in the TDFWs. The architecture of the new proposed system maps the input of different dimensions to different groups feature nodes by 3DFWS. In the enhancement layer, feature nodes are mapped to enhancement nodes. Moreover, feature nodes and increment nodes can be concatenated into a matrix to map the total output of the novel system by the full connection layer. Finally, the semi-physical simulation experiment is designed to demonstrate the effectiveness of the novel TDFW-BLS. Meanwhile, it is compared with some existing methods and the results have shown superior performance.

Supervisory Control of Multiple Switching Laws With Performance Guidance for Aeroengines

This brief is concerned with the problem of speed regulation control for a two-spool turbofan engine. Firstly, after analyzing the operation characteristics of the aeroengine, we give multiple switched equilibrium manifold expansion (EME) models on the basis of multiple operation modes. Meanwhile, the switching laws are based on the performance indexes that reflect the operation characteristics of the aeroengine in different operation modes. Then, a supervisor is proposed to orchestrate multiple switching laws through checking which operation mode the aeroengine operates in. Furthermore, to enhance the robustness of the aeroengine control system, an optimal control strategy is employed. However, as an acknowledged difficult problem, the analytic nonlinear optimal controller can be hardly obtained. Therefore, we present a modified linear quadratic regulator algorithm for the controller design and give a notion of an EME controller. Moreover, we offer a design process of the switching controllers and present a sufficient condition of the asymptotic stability of the closed-loop switched system for the aeroengine. Finally, a software simulation and a semiphysical simulation experiment for some aeroengine are provided to demonstrate the effectiveness of the proposed method.