Topic
Open-loop controller
About: Open-loop controller is a research topic. Over the lifetime, 16148 publications have been published within this topic receiving 224014 citations. The topic is also known as: non-feedback controller & open-loop control law.
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Papers
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TL;DR: A novel approach is proposed to model the behavior of a commercial 1.8deg hybrid stepper motor accurately and efficiently and model-based damping algorithms for both open-loop control and servo control are proposed.
Abstract: It is well known that commercial hybrid stepper system has one or more low-speed resonant points. However, this characteristic cannot be accurately modeled without high-order equations or complicated measurement of motor parameters. In this paper, a novel approach is proposed to model the behavior of a commercial 1.8deg hybrid stepper motor accurately and efficiently. Also, model-based damping algorithms for both open-loop control and servo control are proposed. Simulation and experimental results show that the proposed algorithms can effectively eliminate low-speed resonance and vibration of the stepper system. The algorithms are efficient enough to be implemented on commercial DSP-based controllers without sacrificing motion control performance.
65 citations
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TL;DR: In this paper, a robust proportional integral, derivative (PID) controller for a hydraulic turbine generator governor using a frequency-response technique is presented. But the design and analysis of a robust PID controller is not discussed.
Abstract: The design and analysis of a robust proportional, integral, derivative (PID) controller for a hydraulic turbine generator governor using a frequency-response technique is presented. The approach uses data from literature on the turbine and on the interconnected system in various modes of operation through a model in the literature to design a single PID controller to guarantee stability and performance over the entire operating range. To ensure stability of the loop for as yet unanticipated operating situations, gain margin, and phase margin, constraints are imposed during the design of the controller. The new PID governor is compared with a high-order controller designed by the H/sub /spl infin// method.
65 citations
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TL;DR: In this paper, two new controllers for the Hubble Space Telescope (HST) using covariance control techniques were designed for the HST to improve the response to unexpected thermally induced disturbances, and the results show that the required pointing error specifications can be achieved with 85% less control effort and that the error due to the finite-wordlength implementation of the controller can easily be included in the optimal control design process.
Abstract: To improve the response to unexpected thermally induced disturbances, two new controllers are designed for the Hubble Space Telescope (HST) using covariance control techniques. The first controller minimizes the required control effort subject to inequality constraints on the output covariance matrix. The second controller is designed to satisfy both output covariance constraints and controller covariance constraints. The importance of the controller covariance constraint is to properly scale the controller for digital implementation in the control computer using fixed-point arithmetic. We provide a technique to integrate modeling, control design, and signal processing (in HST's fixed-point control computer), since these problems are not separable. Covariance control can easily accommodate the roundoff error and computational time delay. Compared with the existing HST controller design, the results show that the required pointing error specifications can be achieved with 85% less control effort and that the error due to the finite-wordlength implementation of the controller can easily be included in the optimal control design process.
65 citations
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TL;DR: The cost controller proved to be a good tool for automating the search of the most profitable setpoints of the effluent quality controllers for a given cost setpoint.
65 citations
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TL;DR: It is shown by the experimental results that the favorable position tracking performance for the DC motor driver can be achieved by the proposed APID control scheme after learning of the controller parameters.
Abstract: The proportional-integral-derivative (PID) controller has been extensively applied in practical industry due to its appealing characteristics such as simple architecture, easy design and parameter tuning without complicated computation. However, the PID controller usually needs some a priori manual retuning to make a successful industrial application. To attack this problem, this paper proposes an adaptive PID (APID) controller which is composed of a PID controller and a fuzzy compensator. Without requiring preliminary offline learning, the PID controller can automatically online tune the control gains based on the gradient descent method and the fuzzy compensator is designed to eliminate the effect of the approximation error introduced by the PID controller upon the system stability in the Lyapunov sense. Finally, the proposed APID control system is applied to a DC motor driver and implemented on a field-programmable gate array (FPGA) chip for possible low-cost and high-performance industrial applications. It is shown by the experimental results that the favorable position tracking performance for the DC motor driver can be achieved by the proposed APID control scheme after learning of the controller parameters.
64 citations