Archive | Automatic Controls and Robotics

ISA Automatic Controls and Robotics Division


Your New Robot Colleague is Coming Out of its Cage

When asked how they envision a robot, most people either think of huge, unwieldy robots working in fenced-off areas in large factories, or they think of futuristic cyberbots mimicking human behavior. But somewhere between these two scenarios lies an emerging reality: a new class of robots, dubbed collaborative robots due to their ability to work […]

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Fig. 1. Three-phase two-level PWM inverter.

A novel sliding-mode control of induction motor using space vector modulation technique

Abstract: This paper presents a novel sliding-mode control method for torque control of induction motors. The control principle is based on sliding-mode control combined with space vector modulation technique. The sliding-mode control contributes to the robustness of induction motor drives, and the space vector modulation improves the torque, flux, and current steady-state performance by reducing […]

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Fig. 1. Continuous-time cascaded delay system.

Digital redesign of analog Smith predictor for systems with input time delays

Abstract: This paper presents a new methodology for digitally redesigning an existing analog Smith predictor control system, such that the cascaded analog controller with input delay can be implemented with a digital controller. A traditional analog Smith predictor system is reformulated into an augmented system, which is then digitally redesigned using the predicted intersampling states. […]

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Fig. 1. Schematic of test system ~HP5high pressure, LP5low pressure!

Modeling supply and return line dynamics for an electrohydraulic actuation system

Abstract: This paper presents a model of an electrohydraulic fatigue testing system that emphasizes components upstream of the servovalve and actuator. Experiments showed that there are significant supply and return pressure fluctuations at the respective ports of the servovalve. The model presented allows prediction of these fluctuations in the time domain in a modular manner. […]

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Fig. 1. Conceptual configuration of the GLC controller.

Design of controller using variable transformations for a nonlinear process with dead time

Abstract: In this work, a globally linearized controller (GLC) for a first-order nonlinear system with dead time is proposed. This is similar to the GLC proposed by Ogunnalke [Ind. Eng. Chem. Process. Des. Dev. 25, 241–248 (1986)] for nonlinear systems without dead time. Two methods are proposed. One is based on the Smith prediction from […]

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Fig. 1. A standard block diagram of the CDM control

Design of PI controllers for achieving time and frequency domain specifications simultaneously

Abstract: This paper deals with the design of PI controllers which achieve the desired frequency and time domain specifications simultaneously. A systematic method, which is effective and simple to apply, is proposed. The required values of the frequency domain performance measures namely the gain and phase margins and the time domain performance measures such as […]

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Fig. 1. Surface of the region.

A simple method to find a robust output feedback controller by random search approach

Abstract: This paper presents a simple but effective method for finding a robust output feedback controller via a random search algorithm. The convergence of this algorithm can be guaranteed. Moreover, the probability to find a solution as well as the number of random trials can be estimated. The robustness of the closed-loop system is improved […]

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Fig. 1. Schematic of inverse modeling of a transducer.

Development of a Virtual Linearizer for Correcting Transducer Static Nonlinearity

Abstract: This paper reports the development of an artificial neural network based virtual linearizer for correcting nonlinearity associated with transducers connected to the data-acquisition system of a computer-based measurement system. In analog processing techniques, nonlinearity is considered to be a very serious problem that at one time was solved frequently by the piecewise linear segment […]

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Fig. 1. Step responses of the nominal closed loop system.

Adaptive predictive functional control of a class of nonlinear systems

Abstract: This paper describes the use of pseudo-partial derivative (PPD) to dynamically linearize a nonlinear system, and aggregation is applied to the predicted PPD, resulting in a model-free adaptive predictive control algorithm for a nonlinear system. The algorithm design is only based on the PPD derived online from the input/output data of the controlled process, […]

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