This study is concerned with the design of a nonsingular decoupled terminal sliding mode controller for a class of fourth-order under-actuated uncertain nonlinear systems with unknown external ...disturbance. For the unmeasured disturbance, a disturbance observer with finite-time convergence of estimation error to zero is proposed. The nonsingular decoupled terminal sliding mode controller is designed by utilizing the output of the proposed disturbance observer. Also, an input saturation constraint and control singularity are considered in the controller design. The finite-time stability and convergence of the disturbance observer are proved for the closed-loop system. In addition, the control of an electrostatically actuated Timoshenko nanobeam subjected to Casimir force is simulated to demonstrate the effectiveness and performance of the proposed control scheme.
The work represents a comparative study of three type of metallic food package used in Romanian food industry. In this paper, three food packages made of low-alloy steel were analyzed. To ...characterize their properties, spectrometric analyzes were performed to determine the chemical composition, microhardness analyzes, optical microscopy and Fourier Transform Infrared Spectroscopy. The investigations on the three samples were achieved through X-ray Fluorescence Spectrometry (XRF) analysis performed with a Spectro XEPOS analyzer, optical microscopy analyzes performed on a Reichert UnivaR optical microscope, and microhardness tests by the Vickers method using the CV - 400 DTS tester / 2 (CV Instruments) and Fourier Transform Infrared Spectroscopy (FTIR) with JASCO 6200 analyzer, equipped with Golden Gate type attenuated total reflection (ATR) device. Following the investigations, the presence of epoxyphenolic resin was confirmed in the case of the first two samples and a layer of polyester in the case of sample three. Finally, conclusions are presented about the qualities of the selected packaging and their properties to keep safe the packaged products for a period of several months to several years.
This unique book extends mechatronics to spatially distributed systems. Issues regarding remote measurements and indirect monitoring and control of distributed systems is presented in the general ...framework of the recently developed ill-posed inverse problems. The book starts with an overview of the main results in the inverse problem theory and continues with the presentation of basic results in discrete inverse theory.
As a first endeavor, an approach for the two- and three-dimensional temperature control of functionally graded (FG) plates by using the inverse solution and the proportional-differential (PD) ...controller is provided. For this purpose, firstly, having the desired temperatures at different locations and times, heat fluxes at the boundaries of the plates are estimated by inverse solution techniques offline. Then, the estimated heat fluxes as feedforward control inputs are combined with a PD controller to introduce a hybrid feedforward–feedback control input to the FG domain in the presence of disturbance and noise. In order to show the efficiency and accuracy of the proposed (inverse
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PD) controller in two- and three-dimensional domains, different distinct examples, which include different boundary conditions, material properties and disturbance sources are presented. It is shown that the presented approach can adjust heat fluxes for control of the temperature accurately; also, the PD controller gains do not need to be re-adjusted for different problems.
In this paper, a three-dimensional transient inverse heat conduction (IHC) procedure is presented to estimate the unknown boundary heat flux of thick functionally graded (FG) plates. For this ...purpose, the conjugate gradient method (CGM) in conjunction with adjoint problem is used. A recently developed three-dimensional efficient hybrid method is employed to solve variable-coefficient initial-boundary-value differential equations of direct problem as a part of the inverse solution. The accuracy of the inverse analysis is examined by simulating the exact and noisy data for problems with different types of boundary conditions and material properties. In addition to rectangular domain, skew plates are considered. The results obtained show good accuracy for the estimation of boundary heat fluxes.
Two-dimensional transient inverse heat conduction problem (IHCP) of functionally graded materials (FGMs) is studied herein. A combination of the finite element (FE) and differential quadrature (DQ) ...methods as a simple, accurate, and efficient numerical method for FGMs transient heat transfer analysis is employed for solving the direct problem. In order to estimate the unknown boundary heat flux in solving the inverse problem, conjugate gradient method (CGM) in conjunction with adjoint problem is used. The results obtained show good accuracy for the estimation of boundary heat fluxes. The effects of measurement errors on the inverse solutions are also discussed.
This paper describes the evolution of the teaching of electrical engineering to mechanical engineering students based on motivation and a pedagogical strategy incorporating interdisciplinary ...mechatronics projects in a learning studio environment. Implementation of student projects within the curriculum has been demonstrated to be highly motivational and educational and has even evolved from "play and learn" into industry-inspired green energy applications as a platform for multiple student competitions. Several examples of successful student projects are discussed. These modules can be used as motivation instruments to gradually enhance the interest of current and future engineering students in mechatronics. In this paper, a summary of student feedback is provided, and benefits, challenges, and lessons learned from this initiative are discussed.
Accurate measurements of positions, velocities, and accelerations in both joint and operational space are required for achieving accurate operational space motion control of robots. Servomotors used ...for joint actuation are normally equipped with position sensors and optionally with velocity sensors for interlink motion measurements. Further improvements in measurement accuracy can be obtained by equipping the robot arm with accelerometers for absolute acceleration measurement. In this paper, an extended Kalman filter is used for multisensor fusion. The real-time control algorithm was previously based on the assumption of a jerk represented as a processed white noise with the zero mean. In reality, the accelerations are varying in time during the arm motion, and the zero mean assumption is not valid, particularly during fast accelerating periods. In this paper, a model predictive control approach is used for predetermining next-time-step jerk such that the remaining term can be modeled as Gaussian white noise. Experimental results illustrate the effectiveness of the proposed sensor fusion approach.
This paper demonstrates a haptic device for interaction with a virtual environment. The force control is added by visual feedback that makes the system more responsive and accurate. There are two ...popular control methods widely used in haptic controller design. First, is impedance control when user motion input is measured, and then, the reaction force is fed back to the operator. The alternative method is admittance control, when forces exerted by user are measured and motion is fed back to the user. Both, impedance and admittance control are also basic ways for interacting with a virtual environment. In this paper, several experiments were performed to evaluate the suitability of force-impedance control for haptic interface development. The difference between conventional application of impedance control in robot motion control and its application in haptic interface development is investigated. Open loop impedance control methodology is implemented for static case and a general-purpose robot under open loop impedance control was developed as a haptic device, while a closed loop model based impedance control was used for haptic controller design in both static and dynamic case. The factors that could affect to the performance of a haptic interface are also investigated experimentally using parametric studies. Experimental results for 1 DOF rotational motion and 2 DOF planar translational motion systems are presented. The results show that the impedance control aided by visual feedback broaden the applicability of the haptic device and makes the system more responsive and accurate.
Room acoustics is an important but difficult part of room design. Good design is achieved more on the basis of acoustic expertise than on pure engineering design. Among the reasons for this situation ...are the limitations due to acoustic measurement system design and the difficulties in solving inverse acoustic room problems given acoustic requirements. This paper investigates the means for improving the room acoustic measurement system and for validating simulation approaches for room acoustics design.
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