The main objective of this paper is to perform a robust controller design using discrete-time sliding mode control (DSMC). In the control scheme, two-degree-of-freedom (2-DOF) control strategy turns the DSMC, which ge...
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ISBN:
(纸本)9781479978632
The main objective of this paper is to perform a robust controller design using discrete-time sliding mode control (DSMC). In the control scheme, two-degree-of-freedom (2-DOF) control strategy turns the DSMC, which generally utilized state feedback into output feedback controller. The designed control scheme is considered with feedback and feedforward combination by implementing the zero phase error tracking control (ZPETC), which particularly intended for the nonminimum phase electro-hydraulic actuator (EHA) system application. In the experimental works, a sinusoidal trajectory with different frequencies is employed to assess the DSMC performance under nonlinear and uncertain condition. Experimental results show the DMSC with perfect tracking control approach is capable to reduce the phase lag occurred due to nonlinear phenomenon. The proposed controller also is highly robust under various points of trajectories and significantly shows enhancement in tracking control performance as compared to the conventional controllers.
Because the surface engineering is becoming an increasingly viable alternative to the constructive changes made to improve the efficiency of internal combustion engines, have been proposed and tested various types of ...
Because the surface engineering is becoming an increasingly viable alternative to the constructive changes made to improve the efficiency of internal combustion engines, have been proposed and tested various types of coatings of some organs of internal combustion engines. One vital organ is the engine valves, which is subjected during operation to combined thermal, mechanical, corrosion and wear solicitations, which are leading to severe corrosion and complete breakdown. In this paper were analyzed aspects of valves wear and the active surfaces were coated using the atmospheric plasma spraying method (APS) with two commercial powders: Ni-Al and YSZ. Microstructural analyzes were made on these layers and also observations regarding the possibility of using them as thermal barrier and anti-oxidant coatings.
The general and traditional opinion regarding the materials used to build bells, musical instruments or sound transmitters is that those materials must be only from the bronze alloyed with tin category. In order to ap...
The general and traditional opinion regarding the materials used to build bells, musical instruments or sound transmitters is that those materials must be only from the bronze alloyed with tin category. In order to approach this idea from a scientific point of view, the materials with acoustic properties must be analyzed starting from the physical theory and experimental determination that sound travels only through bodies with elastic properties. It has been developed an experimental white cast iron, medium alloyed with Cr and Ni, in order to obtain a material with special acoustic properties. There were determined on specific samples: the vibration damping capacity, the unit energy, the tensile strength and elasticity modulus. These properties were correlated with the properties of other known acoustic materials.
Due to the development of thermal spray deposition technologies, thus obtained layers have more applications and fields of use. One of the coatings with increased application is the one produced from Ni-based self-flu...
Due to the development of thermal spray deposition technologies, thus obtained layers have more applications and fields of use. One of the coatings with increased application is the one produced from Ni-based self-fluxing alloys, which besides the good wear resistance, shows a satisfactory corrosion resistance. In this study it was observed the behavior of three types of coatings produced by Flame Spray method, both at wear and especially corrosion in the environment simulating acid rain. As a result of the experiments it was found that these layers became compact enough after applying the self-fluxing heat treatment, so in their structure are not present defects such as pores and micro-cracks, unmelted particles etc., which could be points of corrosion initiation.
A novel micro tactile display device to display the elasticity of human soft tissues is presented in this paper. The device consists of 16 units in the form of a 4 × 4 units array. Each unit consists of two subst...
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A novel micro tactile display device to display the elasticity of human soft tissues is presented in this paper. The device consists of 16 units in the form of a 4 × 4 units array. Each unit consists of two substrates separated by a 1.75 mm spacer. The first substrate holds a stiffness display pin (1 mm × 1 mm) which is supported by two Shape Memory Alloy (SMA) springs in parallel to provide tunable stiffness. A strain gauge on top of this substrate is used to measure the force applied on that pin. The other substrate includes a planar coil forming a non-contact eddy current sensor that is used to measure the deflection of the pin when subjected to an external force. Both the strain gauge and the eddy current sensors provide feedback signals that are used for characterization and control of the stiffness. Finite element simulation shows that the stiffness range of the designed device matches the range of elasticity of human soft tissues and the eddy current sensor detects up to 1.75 mm deflection which is suitable for characterization purposes. The simulation also studies the cross talk that possibly happen among the eddy current sensors due to the magnetic field.
Correctly coding materials and identifying characters marked on materials are very important for steel manufacturing industry to realize informatization management and intelligent manufacturing. However, the steel pro...
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Correctly coding materials and identifying characters marked on materials are very important for steel manufacturing industry to realize informatization management and intelligent manufacturing. However, the steel products manufacturing is often in a high temperature environment, and there are a lot of material storage and retrieval processes, workers are not easily close to the environment and complete tasks, so it is a great challenge to automatically mark and identify characters on the steel products. This paper presents a framework of label characters marking and management for steel materials, furthermore, a kind of marked characters online detection and tracking method has been provided based on machine vision. In addition, some experiments have been done in BaoSteel to mark characters on hot billets and recognize them in multi situations, and the results show that the proposed method is practical, and has provided a helpful exploration in obtaining accurate fundamental data for the intelligent manufacturing system in steelworks.
In this paper is presented a way to measure the triaxial state of strain and stress using strain gauge rosette for residual stress measurements and a sensitive pin with a small strain gauge glued on the plane surface ...
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In this paper is presented a way to measure the triaxial state of strain and stress using strain gauge rosette for residual stress measurements and a sensitive pin with a small strain gauge glued on the plane surface of the cylinder. It is proposed an upgraded version of the biaxial state of stress measurement method verified by finite element analysis.
Due to injuries that occur on the ankle joint, everyday all around the world, more and more rehabilitation devices have been developed in recent years. The prices for ankle rehabilitation systems are still high, thus ...
Due to injuries that occur on the ankle joint, everyday all around the world, more and more rehabilitation devices have been developed in recent years. The prices for ankle rehabilitation systems are still high, thus we developed a new device that we indented to be low cost and easy to manufacture. A model of an ankle rehabilitation device is presented in this paper. The device has two degrees of freedom, for flexion-extension and inversion-eversion move, and will ensure functionality with minimum dimensions. For the 3D model that we design, the dimensions are taken so that the proposed system will ensure functionality but also have a small dimensions and low mass, considering the physiological dimensions of the foot and lower leg.
Background：Magnetic anchored surgical instruments （MASI）,relying on magnetic force,can break through the limitations of the single port approach in *** characteristic abdominal wall thickness （ICAWT） deeply influ...
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Background：Magnetic anchored surgical instruments （MASI）,relying on magnetic force,can break through the limitations of the single port approach in *** characteristic abdominal wall thickness （ICAWT） deeply influences magnetic force that determines the safety of *** purpose of this study was to research the abdominal wall characteristics in MASI applied environment to find ICAWT,and then construct an artful method to predict ICAWT,resulting in better safety and feasibility for ***：For MASI,ICAWT is referred to the thickness of thickest point in the applied *** determined ICAWT through finding the thickest point in computed tomography *** also investigated the traits of abdominal wall thickness to discover the factor that can be used to predict ***：Abdominal wall at C point in the middle third lumbar vertebra plane （L3） is the thickest during chosen *** layer thickness plays a more important role in abdominal wall thickness than muscle layer thickness.＂BMI-ICAWT＂ curve was obtained based on abdominal wall thickness of C point in L3 plane,and the expression was as follow：f（x） =P1 × x^2 ＋ P2 x x ＋ P3,where P1 =0.03916 （0.01776,0.06056）,P2 =1.098 （0.03197,2.164）,P3 =-18.52 （-31.64,-5.412）,R-square：***：Abdominal wall thickness of C point at L3 could be regarded as *** could be a reliable predictor of *** the light of ＂BMI-ICAWT＂ curve,we may conveniently predict ICAWT by BMI,resulting a better safety and feasibility for MASI.
A new methodology to determine experimentally the Young's modulus of the human fingers has been developed by the authors. The methodology consist in the experimentally variation of the elastic deformation for the ...
A new methodology to determine experimentally the Young's modulus of the human fingers has been developed by the authors. The methodology consist in the experimentally variation of the elastic deformation for the finger in contact with a steel cylinder normal loaded from zero to 10 N. The Hertzian model for elastic deformation specific to a point contact between a cylindrical object and the index finger has been used to curve fitting the experimental curve for elastic deformation of the finger in the vicinity of imposed forces from 0.5N to 10 N. Values between 0.07 MPa and 0.2 MPa for Young's modulus of the finger have been obtained, in agreement with the values determined by the other authors using ball finger contacts or finger plane surface contacts.
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