Good knowledge of sorption behaviour is necessary in drying and storing agricultural products. Equilibrium moisture content for adsorption and desorption of Lotus comiculatus L forage was investigated in the temperatu...
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Good knowledge of sorption behaviour is necessary in drying and storing agricultural products. Equilibrium moisture content for adsorption and desorption of Lotus comiculatus L forage was investigated in the temperature range of 30 - 50 ° C and water activity ranging from 0.4 to 0.99. Three models available in the literature were evaluated: Halsey, Henderson and Oswin. Best results were obtained, both for stems and leaves, with a specially developed exponential model. Equilibrium moisture content, relative air humidity, temperature of the material stored and near ambient air temperature were major factors controlling the drying process in a deep layer.
In this work the solution of generalized Lyapunov equations using an extension of Hammarling’s method is described. Lyapunov equations are used in multiple applications, e.g. model reduction in linear control problem...
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In this work the solution of generalized Lyapunov equations using an extension of Hammarling’s method is described. Lyapunov equations are used in multiple applications, e.g. model reduction in linear control problems. The sequential algorithms have been implemented making use of standard linear algebra libraries BLAS and LAPACK, and they include block versions. In the parallel algorithms, libraries PBLAS and ScaLAPACK have been used. Experimental results show good performances. A cluster of PC's connected via Fast Ethernet under Linux operating system has been used to obtain the experimental results.
An inverse problem of dynamics is considered, namely, it is necessary to reconstruct unknown controls (perturbations) applied to a nonlinear dynamical system and generating an observable motion of the system. The info...
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An inverse problem of dynamics is considered, namely, it is necessary to reconstruct unknown controls (perturbations) applied to a nonlinear dynamical system and generating an observable motion of the system. The information for reconstruction is obtained by approximate measurements of varying informational sets of the system. The reconstruction is carried out in real time. This problem is known to be ill-posed. It is proposed to solve it by means of constructive, physical feasible, regularizing positional algorithms for the stable dynamical approximation of unknown controls.
Fundamental tracking control algorithms of a differentially steered wheeled mobile robot with two conventional driven wheels are studied through analyzing the robot's inherent kinematics. This includes the trackin...
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Fundamental tracking control algorithms of a differentially steered wheeled mobile robot with two conventional driven wheels are studied through analyzing the robot's inherent kinematics. This includes the tracking variable assignment as well as the tracking singularity and position-orientation tracking decoupling problems. Globally convergent tracking control algorithms are proposed which can exactly track any differentiable reference path. A fundamental motion orientation equation under the condition of exact position tracking is developed, and it is shown that it is not possible to exactly track both position and orientation concurrently for this kind of mobile robot configuration if the tracking point is not on the baseline. Examples are provided illustrating the tracking ability of the developed control algorithms.
This paper outlines a control framework being developed for the TRYM model. The current procedure minimises a quadratic social loss function that targets non-steady-state settings for unemployment and inflation. The i...
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This paper outlines a control framework being developed for the TRYM model. The current procedure minimises a quadratic social loss function that targets non-steady-state settings for unemployment and inflation. The iterative technique is described in detail, and illustrated using the example of a temporary terms of trade shock. The effects of the shock on the model are compared for two separate policy regimes, one using the default TRYM policy reactions, and the other from the optimal control procedure. The limitations of using control techniques as an aid to the policy-formation process, and the benefits to be derived from implementing optimal control on a model like TRYM, are briefly discussed. Copyright (C) 1997 Elsevier Science Ltd.
A motion simulator is studied within the framework of a multilink robotic manipulator and a class of inverse kinematic algorithms are investigated. Human subjects, for this motion simulator, sit at the end effector an...
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A motion simulator is studied within the framework of a multilink robotic manipulator and a class of inverse kinematic algorithms are investigated. Human subjects, for this motion simulator, sit at the end effector and are subjected to all relative motions of the respective links. From the perspective of the subject, one undesired artifact of this simulation occurs when Coriolis accelerations are induced at the end effector as a consequence of a coordinate frame moving relative to another moving frame. This paper adapts the inverse kinematic solution to those which have a minimum Coriolis component and can be used to control the motion simulator. A simple feedback control law is derived which, it turns out, has an additional interpretation as the solution of a related linear quadratic optimization problem.
This paper outlines a control framework being developed for the TRYM model. The current procedure minimises a quadratic social loss function that targets non-steady-state settings for unemployment and inflation. The i...
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This paper outlines a control framework being developed for the TRYM model. The current procedure minimises a quadratic social loss function that targets non-steady-state settings for unemployment and inflation. The iterative technique is described in detail, and illustrated using the example of a temporary terms of trade shock. The effects of the shock on the model are compared for two separate policy regimes, one using the default TRYM policy reactions, and the other from the optimal control procedure. The limitations of using control techniques as an aid to the policy-formation process, and the benefits to be derived from implementing optimal control on a model like TRYM, are briefly discussed. Copyright (C) 1997 Elsevier Science Ltd.
The objective of this paper is to review the state-of-the-art and recent developments in Switched Reluctance Motor (SRM) drives. The interest for improved performance and reliability has motivated many SRM advances in...
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The objective of this paper is to review the state-of-the-art and recent developments in Switched Reluctance Motor (SRM) drives. The interest for improved performance and reliability has motivated many SRM advances in the recent years. Even after almost 30 years of research in SRM, which might appear to be the simplest of all machines, there remain critical issues to be explored to gain deeper insight into the SRM technology. The paper briefly discusses the historical background and the basic operating principles of the motor. The topics discussed include the current state of research in converter topologies, control algorithms, torque ripple, noise, and sensorless operation. Recent advances in the field of SRMs indicates that they will have an increasing influence in the area of variable speed drives in the coming decades.
In the last ten years Model Based Predictive control (MBPC) has proved itself as one of the most successful advanced control tools. Its capability to handle processes with 'difficult' dynamics, has allowed imp...
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In the last ten years Model Based Predictive control (MBPC) has proved itself as one of the most successful advanced control tools. Its capability to handle processes with 'difficult' dynamics, has allowed improved control on critical loops with long time delays, constraints, feed-forwarding, over-rides, etc. Moreover, MBPC algorithms are able to perform multivariable control on processes characterised by strongly interactive loops, which have always been one of the toughest control problems. Due to the computational burden of such sophisticated algorithms, and the engineering skills required for a successful implementation, MBPC diffusion has been limited, in most cases, to 'money-making-loops', above all in the chemical and petrochemical fields, where even small increases in efficiency or yield produce major savings. The great progress in utilising the always increasing power of digital computers, and in developing and improving user-friendly software environments, provides opportunities for applying highly sophisticated control techniques more quickly, easily and cheaply. This paper introduces the new IDCOM-B(TM) controller;that is, the first multivariable model-predictive control package completely embedded in a DCS as a modular control function. Its unique capability to run inside a standard INFI90 control module, sharing with the base regulatory loops the communication channels, control database and operator interfaces, avoids the cost of an external computer and all the efforts required to interface it with a DCS architecture.
This paper-presents the precision control of drive devices with significant stick-slip, friction. The controller design follows the Pseudo-Derivative Feedback (PDF) control algorithm. Using the second order system mod...
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This paper-presents the precision control of drive devices with significant stick-slip, friction. The controller design follows the Pseudo-Derivative Feedback (PDF) control algorithm. Using the second order system model, the PDF controller offers arbitrary pole placement. In this paper the stability proof for the controller with stick-slip friction is presented. On the basis of this proof the stability criteria are derived. The paper also includes both the computer. simulation and the experimental works to confirm the theoretical result. The experiments conducted on a Traction Type Drive Device (TTDD) shows that control accuracy of as high as +/-/ arc- second is achieved.
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