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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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Journal ArticleDOI
TL;DR: In this paper, a set-point controller composed of a proportional control term and an angular velocity control term is presented, which is a function of the vector measurements and a set of desired vector measurements that are used to compute the orientation error of the rigid body.
Abstract: Set-point regulation and tracking control of a rigid body is considered. The rigid body, which could be a spacecraft, underwater vehicle, or unmanned aerial vehicle, is equipped with various sensors, including those that provide unit-length vector measurements. At no point is the rotation matrix associated with the rigid-body’s orientation parameterized. The control algorithms developed in this paper are posed directly on the special orthogonal group of rigid-body rotations SO(3). The set-point controller presented is composed of a proportional control term and an angular velocity control term. The proportional control term is a function of the vector measurements and a set of desired vector measurements that are used to compute the orientation error of the rigid body. Passive systems theory is used to motivate the use of a strictly positive real angular velocity controller. The set-point regulator is robust to modeling errors associated with the mass distribution of the body. Tracking control is also con...

36 citations

Journal ArticleDOI
TL;DR: Due to FS-MPC's direct manipulation of the VSC switches, the pulsewidth-modulation delay does not exist, while a high sampling rate leads to only insignificant computational delay, and the system achieves far less magnitude and phase roll-off in the high-frequency region that allows considerable increase of dynamic performance compared to conventional control approaches.
Abstract: This paper proposes a new control strategy for grid-connected $LCL$ -filtered voltage source converters (VSCs). It is realized by cascading a proportional-resonant (PR) controller, which regulates the grid-side current, and a finite-set model predictive controller (FS-MPC), which is responsible for controlling the filter's capacitor voltage and active damping of the resonance. The overall control circumvents the drawbacks of using only the FS-MPC to control the converter, such as steady state tracking error, weighting factor tuning complexity, and need to use long prediction horizons for optimal performance, but it keeps its advantageous properties. Namely, due to FS-MPC's direct manipulation of the VSC switches, the pulsewidth-modulation delay does not exist, while a high sampling rate leads to only insignificant computational delay. As a consequence, the system achieves far less magnitude and phase roll-off in the high-frequency region that allows considerable increase of dynamic performance compared to conventional control approaches. Moreover, the inner FS-MPC-based regulator exhibits a flat frequency response, which indicates that there is no need for designing a dedicated AD. The overall control design procedure is then largely simplified as only the proportional gain of the PR controller needs to be tuned. These properties are proved using a describing function method where a linear approximation of the FS-MPC regulated VSC and an inner $LC$ filter is derived in the frequency domain and integrated together with the model of the PR controller and grid side inductor. The controller has been analyzed analytically and validated through experimental results, where design correctness and robustness to grid-side inductance variations have been tested.

36 citations

Journal ArticleDOI
TL;DR: In this paper, a switch control strategy is proposed to deal efficiently and in a transparent way from the user's point of view with the transition between the coarse and the fine operating modes of PSS actuators.
Abstract: The ability to do dexterous automated and semi-automated tasks at the micro- and nano-meter scales inside a Scanning Electron Microscope (SEM) is a critical issue for nanotechnologies. SEM-integrated nano-robotic systems with several Degrees Of Freedom (DOF) and one or several end-effectors have therefore widely emerged in research laboratories and industry. The Piezoelectric Stick-Slip (PSS) is one of the best actuation principle for SEM-integrated nano-robotic systems as it has two operating modes, namely a coarse positioning mode with long travel range, and a fine positioning mode with a resolution of the order of the nanometer. The main contribution of this paper is the design of a switch control strategy to deal efficiently and in a transparent way from the user's point of view, with the transition between the coarse and the fine operating modes of PSS actuators. The aim is to be able to perform positioning tasks with a millimeter displacement range and a nanometer resolution without worrying about the mode of operation of the actuator. The coarse mode and the fine mode are respectively controlled with a frequency/voltage proportional control and a H∞ control. The switch control is based on an internal model of the actuator. Experimental results show the effectiveness of the new mixed coarse/fine mode control strategy to satisfy closed-loop stability and bumpless specifications at the switching time. For the best knowledge of the authors, this result is the first demonstration of such a control capability for PSS actuators.

35 citations

Patent
24 Feb 1988
TL;DR: In this article, a ratio control system for use in a continuously variable transmission is disclosed in conjunction with an improved technique for operation thereof, where individual gain schedules provide proportional gain in response to a selected one of a number of modes dependent upon clutch input speed, transmission belt ratio, or engine set point.
Abstract: A ratio control system for use in a continuously variable transmission is disclosed in conjunction with an improved technique for operation thereof. Individual gain schedules provide proportional gain in response to a selected one of a number of modes dependent upon clutch input speed, transmission belt ratio, or engine set point. Engine speed set point is determined as a function of a set point schedule (114) in conjunction with a limiter (116) and a filter (120) to provide a gradual response to rapid changes in a throttle input or driver demand signal and vehicle speed. The error signal generated as an output of any of the proportional gain loops is integrated (154) and combined (in 104) with a null signal (N0) to provide a signal (e4) to generate a duty cycle for a pulse width modulation controlled electrohydraulic control valve to control the pressure to the primary sheave in a continuously variable transmission system for modifying the belt ratio. The integration function (154) may be used or bypassed at appropriate times to account for physical limitations in the possible range for the belt ratio. Full low and full overdrive conditions are provided through an open loop gain corresponding to maximum and minimum duty cycle signals.

35 citations

Patent
24 Feb 1988
TL;DR: In this article, the belt ratio factor and integral dynamic phase factor are incorporated in the engine speed control loop to provide consistent and accurate response to driver demand variations at differing transmission drive levels.
Abstract: A clutch control system provides and regulates pressure at a clutch (28) for a transmitting torque from an engine (12) to a drive train (30,32) through a continuously variable transmission (18). A positive torque value is determined for each throttle setting and provided as a pressure input signal (62). Engine speed is monitored through a closed loop feedback system (68) to provide an error signal (on 106) to the desired pressure setting. A pressure control loop (110) monitors pressure at the clutch through a closed loop feedback system to maintain the pressure at the clutch at a desired level. Filtering (74,92) is provided in the torque and engine speed loops to provide for a more realistic response to driver demand. Incorporation of belt ratio factor (82) in the engine speed control loop further provides for consistent and accurate response to driver demand variations at differing transmission drive levels. Overall line pressure within the associated hydraulic system further controls a proportional gain in the pressure control loop to provide appropriate response. Phase compensation and integral dynamic phase factors in the pressure control loop further guarantee a zero level steady state error signal and the generation of accurate control over the pressure control valve.

35 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202217
202162
2020110
2019150
2018150