This paper presents a new approach to a robust fuzzy controller design for the bilateral Teleportation system with varying time delays using linear matrix inequalities. Communication channels are considered with different forwarding and returning time delays. The time delays of communication channels are assumed to be unknown and randomly time varying, but the upper bounds of the delay interval and the derivative of the delay are assumed to be known. In order to design the controllers, first, an impedance controller is designed for the master system to achieve desired impedance behavior for the master. Then, nonlinear Euler-Lagrange equation of motion of the slave system is linearized in the neighborhood of some operating points. In the sequel, an open-loop scheme is considered for the slave system. The linear model of the slave system has two imaginary/unstable poles. The slave system is stabilized by a PD-controller to be used in the open-loop scheme. To design the slave controller, the Tele-operator block diagram is rearranged such that the Tele-operator block diagram converts to a standard representation of a feedback control system which helps us to design a robust H-infinity controller for the slave system. The local linear models of the system are combined to form a Takagi-Sugeno fuzzy model of the whole Tele-operation system. A Lyapunov-Krasovskii function is defined to analyze the closed-loop system’s stability and derive a sufficient delay-dependent stability criterion. An H-infinity performance index is defined and the design criteria for the slave controller are expressed as a set of LMIs, which can be tested readily using standard numerical software.

This paper is concerned with the Tele-operation of autonomous vehicles over analog Additive White Gaussian Noise (AWGN) channel, which is subject to transmission noise and power constraint. The nonlinear dynamic of autonomous vehicles is described by the unicycle model and is cascaded with a bandpass  lter acting as encoder. Using the describing function method, the nonlinear dynamic of autonomous vehicles is represented by an approximate linear system. Then, the available results for linear control over analog AWGN channel are extended to account for linear continuous time systems with non-real valued and multiple real valued eigenvalues and for tracking a non-zero reference signal. Subsequently, by applying the extended results on the describing function of autonomous vehicles, a mean square control technique including an encoder, a decoder, and a controller is presented for reference tracking of the Tele-operation of autonomous vehicles over AWGN channel. The satisfactory performance of the proposed control technique is illustrated by computer simulations.

Introduction: Telehealth management systems for elderly people should have the features, capabilities, and infrastructure that meet the diverse needs of home care management. Since there is no valid and reliable questionnaire to determine these requirements, the main purpose of this study was to determine the requirements of a Tele-health monitoring system for elderly people and to present it as a valid and reliable questionnaire. Methods: This study was a descriptive-analytical one that performed in 2019. Questionnaire items were obtained from a systematic review study. For the review phase, the selected keywords such as elderly, home care, Telecare, Telehealth, and information technology from 2013 to October 2019 were searched on selected databases. Results: Based on the findings of this study, the parameters and requirements of Tele-health monitoring system for elderly people were identified in 97 items. Furthermore, the first 31 items of the questionnaire were removed due to low validity and reliability. In the next phase, the final questionnaire with 66 items, content validity ratio of 99%, Cronbach's alpha coefficient (0. 9) and desirable correlation coefficient (r = 0. 85, p-value <0. 05) were designed. Conclusion: In this study, the requirements of Tele-health monitoring system for elderly people were determined and a valid and reliable questionnaire was developed using these requirements. The questionnaire was designed in five parts: applications, functional requirements, non-functional requirements, tools, and communication infrastructure. The results of the present study can be used by health care system designers to determine the applications and requirements of elderly health monitoring systems.

In this article, the advantages of navigation based on dual tone multiple frequencies (DTMF) technique through Telecommunication lines is studied. First, the calculations of direct and inverse kinematics of the manipulator in computer are transferred to the PIC microprocessors center. Next, each PIC is required to control and automate the relevant link separately. The main purpose of this work is making it possible to control the robot via a Telephone line without a modem. In order to apply this idea, computer has analyzed the data received from the operator and inserts the necessary instructions through the serial port using AVR microcontroller in the embedded hardware at the phone line and sending them to the robot hardware. Then the robot performed the processes as a closed loop design and provided the necessary feedback for the computer. Real-time control, low volume of software and hardware computations and the possibility of using the phone lines with low and medium bandwidth in addition to ADSL lines simultaneously, are the special features of this method. In the proposed method, control data and the corresponding feedbacks are transmitted as the remote closed loop control, which can be combined in the developing stages with other control methods such as neural networks which results the maximum productivity. At the end of this work, examination of the time delay of Tele-controller system and experimenting according to the ISO9283 standard, specific to the accuracy of the robot, is carried out.