As a non-linear underactuated system, the tower crane should be controlled to transport the load to reference position quickly and smoothly. The actual tower crane is susceptible to the environment interference during...
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As a non-linear underactuated system, the tower crane should be controlled to transport the load to reference position quickly and smoothly. The actual tower crane is susceptible to the environment interference during operation. Conventional Proportion Integral Derivative(PID) controller cannot deal with this interference. Sliding mode control(SMC) is robust to system uncertainties and external disturbances, but it needs to know the upper bounds of uncertainties and external perturbations, which are usually unknown in practical systems. Adaptive backstepping sliding mode control(ABSMC) is used to adaptively estimate the uncertainties and external disturbances, and the stability of the system is proved based on Lyapunov theory. Compared with SMC, the proposed ABSMC has strong robustness.
The saturation phenomenon often happens to the regulator in the start-up procedure of electric vehicles. And the dynamic and static performance of the motor will be worse while this phenomenon lasts longer. In this pa...
The saturation phenomenon often happens to the regulator in the start-up procedure of electric vehicles. And the dynamic and static performance of the motor will be worse while this phenomenon lasts longer. In this paper, firstly we will analyze the causes of this phenomenon, and then propose an effective method to solve the regulator saturation. Based on traditional double-loop vector control, this method increased the voltage cut-off negative feedback and combined the state feedback linearization to realize the dynamic decoupling between currents and solve the current regulator saturation problem which happens during start-up procedure. Finally, the feasibility and effectiveness of the proposed method were verified by simulation experiments, and the comprehensive performance of the motor, including speed range, speed tracking performance and dynamic response, was improved.
Particulate environment is frequently encountered in the millimeter wave propagation path. The particles usually produce scattering and absorption to the millimeter wave. Unfortunately, these particles usually have di...
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ISBN:
(数字)9781728129938
ISBN:
(纸本)9781728129945
Particulate environment is frequently encountered in the millimeter wave propagation path. The particles usually produce scattering and absorption to the millimeter wave. Unfortunately, these particles usually have different size, ingredients and even a mixture of many elements. This paper presents a preliminary study of the attenuation of particles on millimeter wave transmission. The dielectric property of water sand and ice were also discussed. The study was conducted at 110 GHz and 220 GHz. Calculation was based on the Mie theory. A full wave simulation was also conducted to better understand the attenuation effect.
The phenomenon of cracks on the surface of buildings is widespread. The existence of cracks affects the normal use of buildings, shortening the service life, seriously damaging the structure of buildings, resulting in...
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In this paper, the problem of non-negative edge consensus of undirected networked linear time-invariant systems is addressed by associating each edge of the network with a state variable, for which a distributed algor...
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In this paper, the problem of non-negative edge consensus of undirected networked linear time-invariant systems is addressed by associating each edge of the network with a state variable, for which a distributed algorithm is constructed. Sufficient conditions referring only to the number of edges are derived for non-negative edge consensus of the networked systems. Subsequently, the linear programming method and a low-gain feedback technique are introduced to simplify the design of the feedback gain matrix for achieving the non-negative edge consensus. It is found that the low-gain feedback technique has a good effect on the non-negative edge consensus of the networked systems subject to input saturation. Numerical simulations are presented to verify the effectiveness of the theoretical results.
A 3D printer system for selective laser sintering technology is used to establish a mathematical model of the relationship between laser power and temperature by using the recursive least squares method. Based on this...
A 3D printer system for selective laser sintering technology is used to establish a mathematical model of the relationship between laser power and temperature by using the recursive least squares method. Based on this model, the internal model control method is used to design the controller to realize the actual 3D printer. Temperature control, simulation analysis of internal model control and traditional PID control effects. The experimental results show that the feasibility, accuracy and internal model control of the recursive least squares identification model are fast, easy to implement, robust, and only one adjustable parameter, easy to adjust.
Large amounts of data are produced in system operation, and how to extract effective information from these data has become an important research topic in the industrial application. Dimensionality reduction is a way ...
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Large amounts of data are produced in system operation, and how to extract effective information from these data has become an important research topic in the industrial application. Dimensionality reduction is a way to refine the data. Because of the low efficiency of the existing methods, these methods can't discover the internal structure of the data. Regarding these problems, a distributed method of dimensionality reduction based on clustering is proposed, which includes the following steps:(1) Clustering the data into some small classes according to the similarity between the data variables; (2) reducing the dimension of data in a small class after being clustered respectively; (3) merging the data after being reduced dimension; (4) classifying the data after being merged by support vector machine (SVM). The data in the simulation is the test data, and the results show that the methods proposed in this paper are better than the existing dimensionality reduction methods.
For the requirements of the laser temperature in additive manufacturing, there is a high precision and high heat need in the industry. The method is proposed to estimate the temperature of laser point, which is based ...
For the requirements of the laser temperature in additive manufacturing, there is a high precision and high heat need in the industry. The method is proposed to estimate the temperature of laser point, which is based on CNN. In this method, a model of CNN is carried out. The collected laser thermal radiation images are used to train the model. Image recognition and isotherm estimation can be obtained by the trained model. The conclusion can be verified by the experiment. The isotherm and temperature of the laser can be measured efficiently in this method.
Aiming at the effect of selective laser sintering technology used in 3D printing, the recursive least squares method was applied to fitting a controlsystem model for quantification the relationship between laser powe...
Aiming at the effect of selective laser sintering technology used in 3D printing, the recursive least squares method was applied to fitting a controlsystem model for quantification the relationship between laser power and corresponding temperature in this paper. The internal model control method is considered based on the establishing model. The controller is put into the actual 3D printing power controlsystem for controlling the laser power. In the experiment, both internal model controller and the PID controller for the 3D printer are researched and deployed for comparing the their effects in the paper. The experimental result illustrates that the IMC based on the recursive least squares method is of effectiveness.
Aiming at the high demands of temperature and precision in the aspect of additive manufacturing, a method based on CNN was proposed for estimating measurement. The network was trained through the collected laser therm...
Aiming at the high demands of temperature and precision in the aspect of additive manufacturing, a method based on CNN was proposed for estimating measurement. The network was trained through the collected laser thermal radiation images for image recognition and isotherm estimation after modeling a CNN. The experimental conclusion verifies that the isotherm detection and temperature estimation of the laser point can be efficiently implemented in proposed method.
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