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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TL;DR: It is shown that the proposed adaptive scheme can dynamically tune the controller parameters during visual servoing, so as to improve its initial performance based on parameters obtained while mimicking the model-based controller.
Abstract: This paper is concerned with the design and implementation of a distributed proportional-derivative (PD) controller of a 7-degrees of freedom (DOF) robot manipulator using the Takagi-Sugeno (T-S) fuzzy framework. Existing machine learning approaches to visual servoing involve system identification of image and kinematic Jacobians. In contrast, the proposed approach actuates a control signal primarily as a function of the error and derivative of the error in the desired visual feature space. This approach leads to a significant reduction in the computational burden as compared to model-based approaches, as well as existing learning approaches to model inverse kinematics. The simplicity of the controller structure will make it attractive in industrial implementations where PD/PID type schemes are in common use. While the initial values of PD gain are learned with the help of model-based controller, an online adaptation scheme has been proposed that is capable of compensating for local uncertainties associated with the system and its environment. Rigorous experiments have been performed to show that visual servoing tasks such as reaching a static target and tracking of a moving target can be achieved using the proposed distributed PD controller. It is shown that the proposed adaptive scheme can dynamically tune the controller parameters during visual servoing, so as to improve its initial performance based on parameters obtained while mimicking the model-based controller. The proposed control scheme is applied and assessed in real-time experiments using an uncalibrated eye-in-hand robotic system with a 7-DOF PowerCube robot manipulator.
77 citations
TL;DR: In this paper, a controller design methodology is given for a quadratic boost converter with a single switch using current-programmed control, which exhibits fourth-order characteristic dynamics with complex right-half plane zeros.
Abstract: A controller design methodology is given for a quadratic boost converter with a single switch using current-programmed control. Nonlinear and linear models are developed, the later exhibits fourth-order characteristic dynamics with complex right-half plane zeros. The proposed control scheme is based on sensing the current of the switch and using it for feedback purposes. When the current loop is introduced, the fourth-order dynamics of the converter are changed to a dominant first order, which simplifies substantially the controller design of the outer loop. For this loop, a conventional controller is designed. The design-oriented analytic results allow the designer to easily pinpoint the control circuit parameters that optimise the converter's performance. At the end, experimental results are given for a 23 W quadratic boost converter where open loop and closed-loop response are compared.
77 citations
11 Jun 2008
TL;DR: In this article, the problem of inverse-optimal re-design of the predictor-based feedback law was studied for LTI finite-dimensional, completely controllable, but possibly open-loop unstable, plants, with arbitrarily long actuator delay.
Abstract: We consider LTI finite-dimensional, completely controllable, but possibly open-loop unstable, plants, with arbitrarily long actuator delay, and the corresponding predictor-based feedback for delay compensation. We study the problem of inverse-optimal re-design of the predictor-based feedback law. We obtain a simple modification of the basic predictor-based controller, which employs a low-pass filter, and has been proposed previously by Mondie and Michiels for achieving robustness to discretization of the integral term in the predictor feedback law. The key element in our work is the employment of an infinite-dimensional "backstepping" transformation, and the resulting complete Lyapunov function, for the infinite dimensional systems consisting of the state of the ODE plant and the delay state. The Lyapunov function allows us to establish inverse optimality of the modified feedback and its disturbance attenuation properties. For the basic predictor feedback, the availability of the Lyapunov function also allows us to prove robustness to small delay mismatch (in both positive and negative directions).
77 citations
21 May 1990
TL;DR: A microprocessor-based solar tracking controller was designed and fabricated and is capable of acquiring photovoltaic and meteorological data from a photvoltaic system and controlling battery/load.
Abstract: A microprocessor-based solar tracking controller was designed and fabricated. In addition to tracking, the controller is capable of acquiring photovoltaic and meteorological data from a photovoltaic system and controlling battery/load. These features are extremely useful in autonomous PV power systems installed in remote areas for system control and monitoring. Solar tracking can be achieved in closed-loop and open-loop modes, and the controller can provide either six PWM (pulse-width-modulated) signals for a three-phase, 50 Hz AC motor or four step signals for a stepper motor. The controller has been laboratory tested. >
77 citations
TL;DR: In this article, a non-linear controller that exploits the properties of port-Hamiltonian systems to precisely define the interconnections and energy dissipations of nonlinear processes is presented for a large class of chemical processes.
77 citations