Proportional control

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

Adaptive Controller for Single-Link Flexible Manipulators Based on Algebraic Identification and Generalized Proportional Integral Control

Abstract: In this paper, we propose a fast online closed-loop identification method combined with an output-feedback controller of the generalized proportional integral (GPI) type for the control of an uncertain flexible robotic arm with unknown mass at the tip, including a Coulomb friction term in the motor dynamics. A fast nonasymptotic algebraic identification method developed in continuous time is used to identify the unknown system parameter and update the designed certainty equivalence GPI controller. In order to verify this method, several informative simulations and experiments are shown.

Transient Control of Electro-Hydraulic Fully Flexible Engine Valve Actuation System

Abstract: Fully flexible valve actuation (FFVA) system, often referred to as camless valvetrain, employs electronically controlled actuators in place of the camshaft to drive the intake and/or exhaust valves for internal combustion engines. This system enables the engine controller to tailor the valve event according to the engine operating condition in real-time to improve fuel economy, emissions, and torque output performance. This paper presents the transient control of a laboratory electro-hydraulic fully flexible valve actuation system. Transient control of the FFVA system includes lift transient, duration transient, phase transient, speed transient, and mode transient. With constant engine speed, the valve profile is periodic in time domain and the lift, phase, and duration transients can be realized using robust repetitive control. When the engine speed varies, the period of the valve profile changes in real-time. This phenomenon poses a fundamental challenge to the transient control problem and repetitive control cannot be applied anymore. To overcome this challenge, we propose a new valve profile consisting of a periodic portion and a dwell portion with time-varying duration. Robust repetitive control is then applied to the periodic portion and proportional plus integral and derivative (PID) control is applied to the dwell portion. These two controls are switched in real-time to achieve asymptotic valve profile tracking performance. To demonstrate the effectiveness of the proposed control method, we show real-time valve-lift profiles used to explore homogeneous charge compression ignition (HCCI) combustion at different engine operating conditions.

Self-tuning control of a nonlinear model of combustion instabilities

Abstract: We present a self-tuning scheme for adapting the parameters of a proportional integral (PI) controller for stabilization of a Culick-type model (1976) of nonlinear acoustic oscillations in combustion chambers. Our adaptation criterion is Lyapunov-based and its objective is the regulation of nonlinear pressure oscillations to zero. We focus on a two-mode model and first develop a design based on an assumption that the amplitudes of the two modes are available for measurement. The adaptation mechanism is designed to stabilize both modes and prevent the phenomenon observed by Candel and coworkers whose adaptive controller stabilizes the first but (under some conditions) apparently destabilizes the second mode. We also prove that the adaptation mechanism is robust to a time delay inherent to the actuation approach via heat release. In order to avoid requirements for sophisticated sensing of the mode amplitudes needed for feedback, we also develop an adaptation scheme which employs only one pressure sensor. In order for the adaptation scheme to be implementable, it is also necessary to know the control input matrix of the system. Rather than performing a linear ID procedure with input excitation, we propose a simple nonlinear ID approach based on limit cycles (internal excitation) which exploits the quadratic character of the nonlinearities. Simulations illustrate the scheme's capability to attenuate limit cycles and its robustness to magnitude- and rate-saturation of the actuator.

Analysis and design of microprocessor-based vector-controlled induction motor drives

Abstract: The design and implementation of controllers for induction motor drives under vector control is considered. The control of induction motor drives is considered in both constant torque and constant horsepower operation regions. A systematic mathematical formulation is presented for designing motor controllers. These include conventional proportional-integral controllers and more advanced frequency-domain optimal controllers. A 32-b microprocessor-based experimental control system is implemented for verifying the proposed control strategies. The theoretical results are validated by the experimental work. >

Continuous-time proportional-integral distributed optimisation for networked systems

Abstract: In this paper, we explore the relationship between dual decomposition and the consensus-based method for distributed optimisation. The relationship is developed by examining the similarities between the two approaches and their relationship to gradient-based constrained optimisation. By formulating each algorithm in continuous-time, it is seen that both approaches use a gradient method for optimisation with one using a proportional control term and the other using an integral control term to drive the system to the constraint set. Therefore, a significant contribution of this paper is to combine these methods to develop a continuous-time proportional-integral distributed optimisation method. Furthermore, we establish convergence using Lyapunov stability techniques and utilising properties from the network structure of the multi-agent system.