Topic

# Proportional control

About: Proportional control is a research topic. Over the lifetime, 3756 publications have been published within this topic receiving 49050 citations.

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24 Jun 1991TL;DR: In this article, a large-signal nonlinear control technique is proposed to control the duty-ratio d of a switch such that in each cycle the average value of a switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient.

Abstract: A new large-signal nonlinear control technique is proposed to control the duty-ratio d of a switch such that in each cycle the average value of a switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient. One-cycle control rejects power source perturbations in one switching cycle; the average value of the switched variable follows the dynamic reference in one switching cycle; and the controller corrects switching errors in one switching cycle. There is no steady-state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with a constant frequency buck converter have demonstrated the robustness of the control method and verified the theoretical predictions. This new control method is very general and applicable to all types of pulse-width-modulated, resonant-based, or soft-switched switching converters for either voltage or current control in continuous or discontinuous conduction mode. Furthermore, it can be used to control any physical variable or abstract signal that is in the form of a switched variable or can be converted to the form of a switched variable. >

691 citations

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TL;DR: In this article, the authors present an analytical method to determine the best possible gains that can be achieved for any class of practical linear AC current controller, including stationary frame PI regulators, stationary frame P+ resonant (PR) controllers, and synchronous d- q frame controllers.

Abstract: Current regulation plays an important role in modern power electronic AC conversion systems The most direct strategy to regulate such currents is to use a simple closed loop proportional-integral (PI) regulator, which has no theoretical stability limits as the proportional and integral gains are increased, since it is only a second order system However, pulsewidth modulation (PWM) transport and controller sampling delays limit the gain values that can be achieved in practical systems Taking these limitations into account, this paper presents an analytical method to determine the best possible gains that can be achieved for any class of practical linear AC current controller The analysis shows that the maximum possible proportional gain is determined by the plant series inductance, the DC bus voltage and the transport and sampling delays, while the maximum possible integral gain is determined primarily by the transport and sampling delays The work is applicable to stationary frame PI regulators, stationary frame controllers with back electromotive force compensation, stationary frame P+ resonant (PR) controllers, and synchronous d- q frame controllers, since they all have identical proportional and integral gains that must be optimized for any particular application

655 citations

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TL;DR: Experimental results for quantized low-order position reference trajectories, which are commonly used in industrial systems, demonstrate the effectiveness of the proposed discrete-time tracking controller.

Abstract: Design and implementation of a discrete-time tracking controller for a precision positioning table actuated by direct-drive motors is considered. The table has acceleration capabilities in excess of 5 G, positioning accuracy at the micron level, and is used in applications such as semiconductor packaging. The controller proposed uses a disturbance observer and proportional derivative (PD) compensation in the feedback path and a zero phase error tracking controller and zero phase low-pass filter in the feedforward path. The existing disturbance observer design techniques are extended to account for time delay in the plant. Practical difficulties with excessive feedforward gains are examined and a low-order filter design method is proposed. Experimental results for quantized low-order position reference trajectories, which are commonly used in industrial systems, demonstrate the effectiveness of the approach.

577 citations

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27 Jun 2005

TL;DR: In this paper, a case study of the Pelican prototype robot is presented, where the authors present a Lyapunov theory for the dynamics of direct-current motors and demonstrate the properties of the dynamic model.

Abstract: Part I: Preliminaries.- Introduction to Part I.- What Does 'Control of Robots' Involve?.- Mathematical Preliminaries.- Robot Dynamics.- Properties of the Dynamic Model.- Case Study: The Pelican Prototype Robot.- Part II: Position Control.- Introduction to Part II.- Proportional Control plus Velocity Feedback and PD Control.- PD Control with Gravity Compensation.- PD Control with Desired Gravity Compensation.- PID Control.- Part III: Motion Control.- Introduction to Part III.- Computed-torque Control and Computed-torque+ Control.- PD+ Control and PD Control with Compensation.- Feedforward Control and PD Control plus Feedforward.- Part IV: Advanced Topics.- Introduction to Part IV.- P'D' Control with Gravity Compensation and P'D' Control with Desired Gravity Compensation.- Introduction to Adaptive Robot Control.- PD Control with Adaptive Desired Gravity Compensation.- PD Control with Adaptive Compensation.- Appendices.- A. Mathematical Support.- B. Support for Lyapunov Theory.- C. Proofs of some Properties of the Dynamic Model.- D. Dynamics of Direct-current Motors.

552 citations

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TL;DR: The proposed control framework provides humans with extended physiological proprioception, so that s/he can affect and sense the remote slave environments mainly relying on her/his musculoskeletal systems.

Abstract: We propose a novel control framework for bilateral teleoperation of a pair of multi-degree-of-freedom nonlinear robotic systems under constant communication delays. The proposed framework uses the simple proportional-derivative control, i.e., the master and slave robots are directly connected via spring and damper over the delayed communication channels. Using the controller passivity concept, the Lyapunov-Krasovskii technique, and Parseval's identity, we can passify the combination of the delayed communication and control blocks altogether robustly, as long as the delays are finite constants and an upper bound for the round-trip delay is known. Having explicit position feedback through the delayed P-action, the proposed framework enforces master-slave position coordination, which is often compromised in the conventional scattering-based teleoperation. The proposed control framework provides humans with extended physiological proprioception, so that s/he can affect and sense the remote slave environments mainly relying on her/his musculoskeletal systems. Simulation and experiments are performed to validate and highlight properties of the proposed control framework

551 citations