Development of a new theory of thermal cutting processes 9. Analysis of the basic thermophysical theories of cutting (Part 6)

Deficiencies are identified in theoretical work by Silin regarding the theory of thermal cutting processes.     

Development of a new theory of thermal cutting processes 1. basic principles

The cycle of papers that begins here—which is a continuation of the cycle published in 2008 (“Vestnik Mashinostroeniya”, nos. 1–12)—establishes the need for a new mathematical theory of thermal cutting processes, capable of adequately describing and explaining the experimental findings. The final papers in the cycle will outline such a theory and confirm its high accuracy. Consistent numbering of formulas and figures will be used throughout, as well as the notation employed in the previous cycle. In the first paper, the basic principles of the mathematical theory are presented.     

Development of a new theory of thermal cutting processes 3. Influence of cutter’s front angle on the cutting temperature and influence of preheating of the blank on the cutting force

Within the framework already established, attention turns to the influence of the cutter’s front angle on the cutting temperature and to the influence of preheating of the blank on the cutting force.     

Comparative analysis of models of accumulation of dispersed damages in metals under irregular variable loading

We analyze models of summation of fatigue damages under irregular variable loading on the basis of linear and nonlinear interpretation of the damage function. We show the necessity of taking into account the main physicomechanical processes in the metal under cyclic loading, which can improve the accuracy of computations.     

Development of a new theory of thermal cutting processes 20. Examples of practical calculations of the cutting temperature (part 3)

The calculation of the cutting temperature is illustrated by examples. The accuracy of practical calculations by the proposed method is confirmed by comparison with independent experimental data.     

Development of a new theory of thermal cutting processes1 4. Analysis of the basic thermophysical theories of cutting (part 5)

Deficiencies are identified in theoretical work by Silin regarding the theory of thermal cutting processes.     

Nonlinear modeling and control of human heart rate response during exercise with various work load intensities

The first objective of this paper is to introduce a nonlinear system to model the heart rate (HR) response during and after treadmill walking exercise. The model is a feedback interconnected system that has components to describe the central and peripheral local responses to exercise and their interactions. The parameters of the model were experimentally identified from subjects walking on a treadmill at different speeds. The stability of the obtained nonlinear model was mathematically proven. The modeling results demonstrate that the proposed model can be useful in examining the cardiovascular response to exercise. Based on the nonlinear model, the second objective is to present a computer-controlled treadmill system for the regulation of HR during treadmill exercise. The proposed nonlinear controller consists of feedforward and feedback components. The designed control system was experimentally verified and the results demonstrated that the proposed computer-controlled treadmill system regulated the HR of the experimental subjects according to two different exercising HR profiles, indicating that it can play an important role in the design of exercise protocols for individuals.      

Robust state estimation for a class of uncertain time-delay systems

This paper considers a robust state estimation problem for a class of uncertain time-delay systems. In this problem, the noise and uncertainty are modelled deterministically via an integral quadratic constraint. The robust state estimation problem involves constructing the set of all possible states at the current time consistent with given output measurements and the integral quadratic constraint. This set is found to be an ellipsoid which is constructed via a linear state estimator.     

A new approach to robust control of hybrid systems over infinitetime

The paper presents a new approach to output feedback robust control synthesis problems for hybrid dynamical systems. The hybrid system under consideration is a composite of a continuous plant and a discrete-event controller. An output feedback H^∞-control problem on an infinite time interval is considered. The main results are given in terms of the existence of suitable solutions to a dynamic programming equation and a Riccati algebraic equation of the H^∞-filtering type. These results show a connection between the theories of hybrid dynamical systems and robust and nonlinear control