Showing papers in "IEEE Control Systems Magazine in 1989"
TL;DR: In this article, an inverted pendulum is simulated as a control task with the goal of learning to balance the pendulum with no a priori knowledge of the dynamics, and reinforcement and temporal-difference learning methods are presented that deal with these issues to avoid unstable conditions.
Abstract: An inverted pendulum is simulated as a control task with the goal of learning to balance the pendulum with no a priori knowledge of the dynamics. In contrast to other applications of neural networks to the inverted pendulum task, performance feedback is assumed to be unavailable on each step, appearing only as a failure signal when the pendulum falls or reaches the bounds of a horizontal track. To solve this task, the controller must deal with issues of delayed performance evaluation, learning under uncertainty, and the learning of nonlinear functions. Reinforcement and temporal-difference learning methods are presented that deal with these issues to avoid unstable conditions and balance the pendulum. >
554 citations
TL;DR: The performance of proportional-integral-derivative control, model reference adaptive control, and fuzzy controllers is compared in terms of steady-state error, settling time, and response time.
Abstract: Consideration is given to the possibility of applying fuzzy algorithms in a microprocessor-based servomotor controller, which requires faster and more accurate response compared with other industrial processes. The performance of proportional-integral-derivative control, model reference adaptive control, and fuzzy controllers is compared in terms of steady-state error, settling time, and response time. Limitations of fuzzy control algorithms are described. >
424 citations
TL;DR: In this paper, a singular perturbation argument is used to show that adaptive control results for rigid robots can be used to control flexible-joint robots provided a simple correction term is added to the control law to damp out the elastic oscillations at the joints.
Abstract: Under the assumption of weak joint elasticity, a singular perturbation argument is used to show that recent adaptive control results for rigid robots can be used to control flexible-joint robots provided a simple correction term is added to the control law to damp out the elastic oscillations at the joints. In this way, fundamental properties of rigid robot dynamics can be exploited to design adaptive control laws for flexible-joint robots that are robust to parametric uncertainty. Experimental results are given to illustrate the theory. >
162 citations
TL;DR: In this article, the assumptions, benefits, and limitations of recent applications of nonlinear filtering, adaptive filtering, modern control, adaptive control, dual control, differential game theory, and modern control design techniques to the air-to-air missile problem are discussed.
Abstract: Current air-to-air missile guidance and control technology is assessed. Areas explored include target state estimation, advanced guidance laws, and bank-to-turn autopilots. The assumptions, benefits, and limitations of recent applications of nonlinear filtering, adaptive filtering, modern control, adaptive control, dual control, differential game theory, and modern control design techniques to the air-to-air missile problem are discussed. >
146 citations
TL;DR: The problem of automatic tuning of simple regulators is examined and an expert system to integrate the two approaches is discussed, resulting in a novel generation of the classical PID (proportional, integral, and derivative) controller.
Abstract: The problem of automatic tuning of simple regulators is examined. The key idea is to design an aid for the process operator, which should use minimal prior information about the system. This is a typical example of a case where it is essential to develop techniques that will give crude but robust estimates. The development has resulted in a novel generation of the classical PID (proportional, integral, and derivative) controller. An application of relay autotuning to temperature control of a distillation column is considered as an example. Adaptive control is then treated. The adaptive algorithms can be viewed as local gradient methods. They require prior information but, given the information, can give very good control performance. The use of an expert system to integrate the two approaches is then discussed. >
120 citations
TL;DR: A theory and the prototype of a neural controller called INFANT that learns sensory-motor coordination from its own experience and relies on the self-consistency between sensory and motor signals to achieve unsupervised learning are presented.
Abstract: A theory and prototype of a neural controller called INFANT, which learns sensory-motor coordination from its own experience, is presented. INFANT adapts to unforeseen changes in the geometry of the physical motor system and to the location, orientation, shape, and size of objects. It can learn to accurately grasp an elongated object without any information about the geometry of the physical sensory-motor system. INFANT relies on the self-consistency between sensory and motor signals to achieve unsupervised learning. It is designed to be generalized for coordinating any number of sensory inputs with limbs of any number of joints. INFANT is implemented with an image processor, stereo cameras, and a five-degree-of-freedom robot arm. After learning, its average position accuracy is within 3% of the length of the arm, and its orientation accuracy is within 60 degrees in solid angle. >
86 citations
TL;DR: In this paper, a trajectory generation and tracking system designed to operate in a very dynamic environment is described, and the system drives a PUMA 260 which is part of a functioning robot ping-pong player.
Abstract: A trajectory generation and tracking system designed to operate in a very dynamic environment is described. The system drives a PUMA 260 which is part of a functioning robot ping-pong player. The goal is to achieve predictable, reliable, high-performance motions at the envelope of robot capabilities. The task is sensor-driven, each motion is unique, and motions have to be changed while they are in progress. The author describes some of the requirements in detail, compares alternative high-performance trajectory types, describes the properties of the quintic polynomials used, discusses how to determine if a trajectory is feasible, and then outlines the implementation and its performance. >
72 citations
TL;DR: It is shown how the relationship between object primitives and a useful set of grasp modes can be learned by an adaptive neural network.
Abstract: A robot hand control system called GeSAM, which is under development at the University of Southern California, is described. The goal of the GeSAM architecture is to provide a generic robot hand controller that is based on a model of human prehensile function. It focuses on the relationship between geometric object primitives and the ways a hand can perform prehensile behaviors. It is shown how the relationship between object primitives and a useful set of grasp modes can be learned by an adaptive neural network. By adding training points as necessary, system performance can be improved, avoiding the tedious job of computing every relationship individually. >
65 citations
TL;DR: In this article, the problem of online tool wear estimation and adaptive process control is discussed, and some results from the research of the authors, including recent laboratory experiments, are presented and two adaptive control systems, one for turning and the other for milling processes, are described.
Abstract: Recent research in the area of adaptive machine tool process control is described. The process control problem in metal-cutting operations is considered, and the problems of online tool wear estimation and adaptive process control are discussed. Research in these areas is then summarized, and some results from the research of the authors, including recent laboratory experiments, are presented. Two adaptive control systems, one for turning and the other for milling processes, are described. >
62 citations
TL;DR: The analysis of delayed control systems is treated, covering the stochastic Lyapunov method approach, the D-partition method, and the method of steps.
Abstract: Integrated control system design, which requires interactions between the disciplines of communication systems and control systems, is introduced. An integrated control system has disparate and spatially distributed subsystems interconnected via a common communication channel. Digital data from sensor to controller and from controller to actuator are multiplexed along with traffic from other control loops and management functions. The asynchronous time-division multiplexing introduces time-varying and possibly stochastic delays in the control loops, degrading system dynamic performance. The analysis of delayed control systems is treated, covering the stochastic Lyapunov method approach, the D-partition method, and the method of steps. >
61 citations
TL;DR: In this paper, an adaptive time-optimal position controller for a direct-drive DC motor with a design based on the model reference adaptive approach is presented, which is achieved by estimating the load inertia by means of a least-squares method and adjusting the reference model accordingly.
Abstract: An adaptive time-optimal position controller for a direct-drive DC motor with a design based on the model reference adaptive approach is presented. The high-acceleration torque of DC motors with permanent magnets permits direct coupling of the load to the motor axis, avoiding the use of a transmission with its inherent disadvantages (such as backlash and friction). However, direct coupling induces a large sensitivity to load variations, so the desired response and the reference model in the adaptive controller are adjusted to the motor capabilities. This is achieved by estimating the load inertia by means of a least-squares method and adjusting the reference model accordingly. The controller is tested on a direct-drive motor, and the results are compared with those obtained with a fixed proportional-integral-derivative controller. >
TL;DR: Commercially available simulation and computer-aided control system design packages can be used in teaching together with real-time software and with special programs developed for specific purposes.
Abstract: The use of computers for classroom presentations, exercises, laboratory experiments, and in projects is discussed. Commercially available simulation and computer-aided control system design packages can be used in teaching together with real-time software and with special programs developed for specific purposes. These possibilities are illustrated by citing many examples of learning and teaching control systems with computers. >
TL;DR: In this paper, a perspective on the need for robust damping controls in the extensive power system that serves western North America is offered, including the dynamics of the power system, known threats to controller robustness, and the information-poor environment in which major damping controllers must be designed and operated.
Abstract: A perspective on the need for robust damping controls in the extensive power system that serves western North America is offered. Key issues include the dynamics of the power system, known threats to controller robustness, and the information-poor environment in which major damping controllers must be designed and operated. The discussion covers power system stability control, reactive-power modulation in the main area, small-signal response during system disturbances, system dynamics tests at the Celilo HVDC terminal, and HVDC modulation and interactions. >
TL;DR: In this article, the design and evaluation for a display of a four-dimensional perspective flight-path predictor (X, Y, Z, and time) are described and five basic principles of human performance are used to guide the choice of display configuration.
Abstract: The design and evaluation for a display of a four-dimensional perspective flight-path predictor (X, Y, Z, and time) are described Five basic principles of human performance are used to guide the choice of display configuration: (1) working memory limitations; (2) object integrality; (3) compatibility; (4) consistency; and (5) visual momentum Each principle is discussed along with the corresponding display and experimental design Twenty-four pilots flew simulated approaches to North American airports, using one of three displays: (1) a display with four-dimensional preview and predictor information, which was configured with inside-out perspective; (2) the same display configured with outside-in perspective; or (3) an inside-out flight director with neither preview nor predictor The results revealed an advantage for predictor/preview information, which was greatest with the inside-out perspective The display aids did not appear to be helpful >
TL;DR: In this article, the general problem of robust stability is defined, and a brief review of Kharotinov-type, edge, and zero-exclusion results is given.
Abstract: Recent results relating to the parametric approach to robust stability are discussed. The general problem of robust stability is defined, and a brief review of Kharotinov-type, edge, and zero-exclusion results is given. Several open research directions are indicated, followed by some remarks on the potential of the approach. >
TL;DR: The Lyapunov direct method is on the verge of being implemented for assessment of online dynamic security as discussed by the authors, but the main bottleneck has been in the proper characterization of the stability boundary and defining the fault-dependent region of attraction locally around the controlling unstable equilibrium points.
Abstract: The Lyapunov direct method is on the verge of being implemented for assessment of online dynamic security. The main bottleneck has been in the proper characterization of the stability boundary and defining the fault-dependent region of attraction locally around the controlling unstable equilibrium points. Now there is a better understanding of this issue, and hence, a number of algorithms have been proposed. Improved generating-unit models and transmission-network models are now being included in the technique. An overview is presented of the theory, practical implementation, and future research. >
TL;DR: An innovative approach, based on open-ended design questions related to bicycles, for the teaching of dynamic systems concepts in an undergraduate mechanical engineering environment shows that the notion of using the bicycle in the classroom as a teaching tool and research topic is feasible.
Abstract: The author reports on an innovative approach, based on open-ended design questions related to bicycles, for the teaching of dynamic systems concepts in an undergraduate mechanical engineering environment. He outlines needs for improved classroom learning, pedagogical methods and underlying philosophy, how the bicycle was introduced as a main portion of the instruction, how the class was managed, supporting materials used, and a summary of major benefits achieved. The results to date show that: (1) the notion of using the bicycle in the classroom as a teaching tool and research topic is feasible; (2) the associated economics are attractive; (3) students are able to apply the abstract notions of systems theory to a concrete problem; (4) the professor can improve his or her expertise in a designated area (such as two-wheeled vehicle dynamics); (5) the percentage and quality of students electing follow-up courses in the systems area increase; and (6) students improve their professional confidence. >
TL;DR: In this article, a multilayer perceptron is used to classify numeric data and assign appropriate symbols to various classes, which results in a type of information extraction, which is similar to what is called data reduction in pattern recognition.
Abstract: A type of neural network, the multilayer perceptron, is used to classify numeric data and assign appropriate symbols to various classes. This numeric-to-symbolic conversion results in a type of information extraction, which is similar to what is called data reduction in pattern recognition. The use of the neural network as a numeric-to-symbolic converter is introduced, its application in autonomous control is discussed, and several applications are studied. The perceptron is used as a numeric-to-symbolic converter for a discrete-event system controller supervising a continuous variable dynamic system. It is also shown how the perceptron can implement fault trees, which provide useful information (alarms) in a biological system and information for failure diagnosis and control purposes in an aircraft example. >
TL;DR: A prototype simulator for dynamical systems, called Hibliz (hierarchical block diagrams with information zooming), which explores some features of modern computer graphics, and simplifies model development by allowing submodels in the form or ordinary differential and algebraic equations rather than assignment statements for derivations andgebraic variables.
Abstract: A prototype simulator for dynamical systems, called Hibliz (hierarchical block diagrams with information zooming), which explores some features of modern computer graphics, is presented. Hibliz supports hierarchical block diagrams to describe the model decomposition and interconnection structure. The user can scroll, pan, and zoom the block diagram continuously in real time. Zooming controls the amount of information displayed. Zooming in a block changes it from an annotated box to a representation showing internal structure with increasing detail. Since the block diagrams can be hierarchical, it is possible to make the description at each level simple and clear. Hibliz also simplifies model development by allowing submodels in the form or ordinary differential and algebraic equations rather than assignment statements for derivations and algebraic variables. >
TL;DR: In this paper, the authors examined voltage-related problems evolving in interconnected electric power systems and their potential importance for system operation and the consequences of novel control designs in the context of the improvement of system operation.
Abstract: Voltage-related problems evolving in interconnected electric power systems are examined. Reasons for these problems are introduced, and their potential importance for system operation is discussed. This physical phenomenon poses problems covering the entire spectrum from proper modeling to control design and communications. Consequences of novel control designs are discussed in the context of the improvement of system operation and the results benefits. >
TL;DR: An approach to this problem that is based on separation of the task into two modules is presented, where a vision module is used to transform an image into a volumetric shape description using generalized cones.
Abstract: The successful execution of grasping by a robot hand requires translation of visual information into control signals to the hand, which produce the desired spatial orientation and preshape for grasping an arbitrary object. An approach to this problem that is based on separation of the task into two modules is presented. A vision module is used to transform an image into a volumetric shape description using generalized cones. The data structure containing this geometric information becomes an input to the grasping module, which obtains a list of feasible grasping modes and a set of control signals for the robot hand. Features of both modules are discussed. >
TL;DR: Two examples of analytic methods for finding the exact form of trade-offs among such desirable qualities as fast response to commands without excessive overshoot, low actuator authority, robustness, low controller complexity, and so on are considered.
Abstract: Two examples of analytic methods for finding the exact form of trade-offs among such desirable qualities as fast response to commands without excessive overshoot, low actuator authority, robustness, low controller complexity, and so on are considered. They are linear quadratic Gaussian theory, where the plant actuator and output variance can be traded off, and Nevanlinna-Pick theory, where, for instance, the achievable disturbance rejection can be traded off in two different bandwidths. In many cases, the limit of performance achievable with a linear time-invariant controller, and thus the exact form of the tradeoffs, can be computed numerically. To demonstrate this trade-off, the design of a regulator for a very typical plant, a double integrator with some excess phase, is examined. The trade-offs are presented for two different measures of robustness with noise sensitivity. The exact form of the trade-offs is determined numerically by using the techniques described in the appendixes. >
TL;DR: In this paper, the Ziegler-Nichols tuning formula was used to explain the heuristics used in the proportional-integral-derivative controllers and in the positioning of controller zeros in pole-placement controllers and phase-lag compensators.
Abstract: The positioning of the controller zeros near the slow process poles though greatly improving the speed of response for a set-point change, can be detrimental to load rejection. This result is used to explain the heuristics used in the Ziegler-Nichols tuning formula for proportional-integral-derivative controllers and in the positioning of controller zeros in pole-placement controllers and phase-lag compensators. >
TL;DR: User-machine interaction is a central component of CONSOLE, a recently developed design package that allows repeated intervention of the designer to deal with multiple trade-offs that appear in the course of numerical optimization.
Abstract: User-machine interaction is a central component of CONSOLE, a recently developed design package. This allows repeated intervention of the designer to deal with multiple trade-offs that appear in the course of numerical optimization. Another important feature of CONSOLE is its two-module structure, which allows complete detection of syntax errors in the problem description before execution of the optimization is attempted. CONSOLE is written entirely in C for fast execution and easy interface with application-specific simulators. It has been used successfully on many design problems in diverse areas. >
TL;DR: In this paper, a multivariable internal model control system was developed for a full-scale distillation column, which is based on a two-input/two-output matrix of linear transfer functions describing column dynamics.
Abstract: A multivariable internal model control system was developed for a full-scale distillation column. The basis for the design of the control is a two-input/two-output matrix of linear transfer functions describing column dynamics. The control system is designed to perform dual composition control of the overhead and bottom products. Hardware constraints dictate multirate sampling of the product concentrations. In addition, the column exhibits inverse response to changes in reflux flow. The multirate sampling is addressed by a unique implementation of a feedforward decoupling control. A reduced-order controller design technique is developed to handle the non-minimum-phase behavior of part of the column. Simulations demonstrate the improvement in control obtained from this approach. >
TL;DR: Implementation aspects of a self-tuning motion controller, which uses the Texas Instruments TMS32010 digital signal processor (DSP) chip, are described, and implementation strategies to overcome limitations of such systems are discussed.
Abstract: Implementation aspects of a self-tuning motion controller, which uses the Texas Instruments TMS32010 digital signal processor (DSP) chip, are described. The potential advantages in using a DSP chip include reduction in operation time, development time, and cost. The self-tuning controller can track variations in system parameters as well as system disturbances. Algorithms are described, experimental results are presented, and implementation strategies to overcome limitations of such systems are discussed. >
TL;DR: In this article, a three-course laboratory sequence in systems and control in the Department of Electrical Engineering at the Ohio State University is presented, where students are exposed to many aspects of sensing, actuation, and implementation issues of real control systems.
Abstract: A three-course laboratory sequence in systems and control in the Department of Electrical Engineering at the Ohio State University is presented. Some specific experiments are outlined from two of the courses, which are intended for seniors and graduate students. Through these courses and associated lectures, students are exposed to many aspects of sensing, actuation, and the implementation issues of real control systems. >
TL;DR: In this article, a multivariable output feedback controller was used to damp the interarea oscillations of a power system consisting of three equivalent generators, each equipped with an exciter, a power stabilizer, and a prime-mover with governor.
Abstract: The application of a multivariable output feedback controller to damp the interarea oscillations of a power system consisting of three equivalent generators, each equipped with an exciter, a power system stabilizer, and a prime-mover with governor, is addressed The multivariable controller uses projective controls and coordinates readily available measurements with control signals applied to the exciter and governor models It is demonstrated that the dynamic response of the power system is greatly improved by the multivariable controller >
TL;DR: In this paper, the authors developed an adaptive drug delivery system for use in regulation of critical care patients suffering from cardiac failure, where adaptive control algorithms combined with expert system techniques are necessary to maintain stable patient statues within narrow physiological bounds in the presence of large plant uncertainty.
Abstract: The goal of this investigation is the development of an adaptive drug delivery system for use in regulation of critical care patients suffering from cardiac failure. It is assumed that adaptive control algorithms combined with expert system techniques are necessary to maintain stable patient statues within narrow physiological bounds in the presence of large plant uncertainty, and a hybrid controller is presented. Its structure is adjusted by an expert system that attempts to select the best control scheme in accordance with the dynamic structure of the plant. An illustrative example is presented, demonstrating the improved performance provided by the hybrid control scheme. >
TL;DR: In this article, the authors used feedback control theory to develop an active noise control system to reduce transient-induced road noise in a vehicle interior, which consists of a detector microphone, a high-speed digital controller, amplifiers, an analog smoothing filter, and a headphone.
Abstract: Feedback control theory is used to develop an active noise control system to reduce transient-induced road noise in a vehicle interior. The system consists of a detector microphone, a high-speed digital controller, amplifiers, an analog smoothing filter, and a headphone. The digital control algorithm uses the output of the microphone combined with the past history of the control signal to calculate the current value of the control signal. This signal is passed through a low-pass filter (to smooth the steps resulting from the digital-to-analog conversion) and then amplified and sent to the headphone near the driver's ear. Two control algorithms are evaluated. A proportional-integral controller reduces the noise by about 5 dB over the 20-to-60 Hz range. A modified generalized minimum-variance controller is able to reduce the noise by about 10 dB for the 25-to-60 Hz range. >