scholarly journals Adaptive Feedback Control for a Pasteurization Process

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 930
Author(s):  
Emil D.J. Rasmussen ◽  
Massimiliano Errico ◽  
Stefania Tronci
Keyword(s):  
Control Strategy ◽  
Adaptive Algorithm ◽  
Pid Controller ◽  
Linear Control ◽  
Control Algorithms ◽  
Time Varying ◽  
Control Parameters ◽  
Adaptive Feedback ◽  
Control Approach ◽  
Adaptive Feedback Control

The milk pasteurization process is nonlinear in nature, and for this reason, the application of linear control algorithms does not guarantee the obtainment of the required performance in every condition. The problem is here addressed by proposing an adaptive algorithm, which was obtained by starting from an observer-based control approach. The main result is the obtainment of a simple PI-like controller structure, where the control parameters depend on the state of the system and are adapted online. The proposed algorithm was designed and applied on a simulated process, where the temperature dependence of the milk’s physical properties was considered. The control strategy was tested by simulating different situations, particularly when time-varying disturbances entered the system. The use of the adaptive rule reduces the variance generally introduced by the PI or PID controller.

Optimal Control of a Flexible Mechanism Using a Combined Feedforward-Feedback Strategy: Simulation and Experiment

1999 ◽  
Author(s):  
Hubertus v. Stein ◽  
Heinz Ulbrich
Keyword(s):  
Optimal Control ◽  
Control Strategy ◽  
System Performance ◽  
High Speed ◽  
Time Varying ◽  
Linkage Mechanism ◽  
Additional Degree ◽  
Control Approach ◽  
Feedback Optimal Control ◽  
Four Bar Linkage

Abstract Due to the elasticity of the links in modern high speed mechanisms, increasing operating speeds often lead to undesirable vibrations, which may render a required accuracy unattainable or, even worse, lead to a failure of the whole process. The dynamic effects e.g. may lead to intolerable deviations from the reference path or even to the instability of the system. Instead of suppressing the vibration by a stiffer design, active control methods may greatly improve the system performance and lead the way to a reduction of the mechanism’s weight. We investigate a four-bar-linkage mechanism and show that by introducing an additional degree of freedom for a controlled actuator and providing a suitable control strategy, the dynamically induced inaccuracies can be substantially reduced. The modelling of the four-bar-linkage mechanism as a hybrid multi body system and the modelling of the complete system (including the actuator) is briefly explained. From the combined feedforward-feedback optimal control approach presented in (v. Stein, Ulbrich, 1998) a time-varying output control law is derived that leads to a very good system performance for this linear discrete time-varying system. The experimental results show the effectiveness of the applied control strategy.

A Fuzzy Controller for Tentacle Cooperative Robots

2001 ◽  
Author(s):  
Mircea Ivanescu ◽  
Nicu Bizdoaca ◽  
Dorian Cojocaru ◽  
Nirvana Popescu ◽  
Decebal Popescu
Keyword(s):  
Control Strategy ◽  
Fuzzy System ◽  
Fuzzy Controller ◽  
Control Algorithms ◽  
Control Parameters ◽  
Software Simulation ◽  
Contact Points ◽  
Simulation Results ◽  
Hard Contact ◽  
The Stability

Abstract A fuzzy system and the control algorithms are proposed to solve the control multi-chain robotic system formed by tentacle manipulators grasping a commune object with hard contact points. The control system contains two parts: the first component is a conventional controller, which implements a control strategy based on the Lyapunov stability, and the second is an adaptive fuzzy controller which adjusts the control parameters by the output of the first level controller. The stability and robustness is investigated and the fuzzy rules are established The fuzzy controller was developed using Matlab and Simulink software. Simulation results are presented and discussed.

Adaptive Control Design for Hydrogen Production via Autothermal Reforming of Methanol

2011 ◽  
Vol 418-420 ◽  
pp. 377-382 ◽  
Author(s):  
Jian Feng Zheng ◽  
Qin Min Yang ◽  
Jian Gang Lu ◽  
You Xian Sun
Keyword(s):  
Hydrogen Production ◽  
Control Strategy ◽  
Control Method ◽  
Control Design ◽  
Autothermal Reforming ◽  
Adaptive Feedback ◽  
Adaptive Feedback Control ◽  
Feedback Control Method ◽  
Complex Chemical Reactions ◽  
Simulation Results

Autothermal reforming of methanol is considered to be a promising choice for hydrogen production. However, due to the fact that a series of complex chemical reactions are involved, an exact mathematical model is extremely hard to be established, which makes the control of the process a recognized difficulty. Therefore, an adaptive feedback control method is proposed in this work for the control of hydrogen production through autothermal reforming of methanol without the requirement of an accurate model. Theoretical analysis proves that this control strategy can achieve very good performance even when the system’s parameters change significantly. Moreover, simulation results demonstrate the feasibility of this approach.

Robust control of two-link manipulator with disturbance torque and time-varying mass loads

2020 ◽  
Vol 42 (9) ◽  
pp. 1667-1674 ◽  
Author(s):  
Zhan Li ◽  
Deqing Huang
Keyword(s):  
Control Method ◽  
Control Algorithms ◽  
Time Varying ◽  
External Disturbances ◽  
Joint Torques ◽  
Control Approach ◽  
And Performance ◽  
And Control ◽  
Mass Loads ◽  
Varying Mass

Robot manipulators play important roles in helping people do repetitive dull jobs marvelously, with taking advantage of redundancy and flexibility. Two-link manipulators are one kind of basic manipulators and are applied in industrial and medical fields. In many application scenarios, external disturbances and time-varying mass loads may appear to have negative vibration effects on motion control for manipulators, and control algorithms that can eliminate such effects are urgently required. This paper proposes a novel control approach for accurate control of two-link manipulator with disturbance joint torques and time-variant mass loads. The proposed control algorithm can make the joint angle error to sustain in a limited bound under disturbances. Meanwhile, the proposed control method is able to make the two joints of the manipulator globally converge to zero if disturbances disappear. Simulation results show the efficiency of the proposed control approach for control of the two-link manipulator with disturbance torques and time-varying mass loads, and performance comparisons with other conventional control methods demonstrate its superiority.

scholarly journals Linearized Discrete Charge Balance Control with Simplified Algorithm for DCM Buck Converter

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3177 ◽  
Author(s):  
Run Min ◽  
Dian Lyu ◽  
Shuai Cheng ◽  
Yingshui Sun ◽  
Linkai Li
Keyword(s):  
Control Strategy ◽  
Balance Control ◽  
Buck Converter ◽  
Linear Control ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Small Signal ◽  
Charge Balance ◽  
Control Approach ◽  
Discrete Charge

In this paper, a linearized discrete charge balance (LDCB) control strategy is proposed for buck converter operating in discontinuous conduction mode (DCM). For DC-DC power converters, discrete charge balance (DCB) control is an attractive approach to improve the output voltage transient response. However, as a non-linear control strategy, the algorithm is complex, which is difficult for implementation. To reduce the complexity, this paper proposes the LDCB control strategy that is derived through linearizing conventional DCB controller. By deriving the differential functions of the DCB control algorithm, the small signal relationship between the input and output of DCB controller is explored. Furthermore, based on the relationship, the LDCB controller is formed through three parallel feed loops to the duty ratio. As a linear control approach, the achieved LDCB controller is greatly simplified for implementation. This not only saves the hardware cost, but also reduces the calculation lag, which provides potential to improve the switching frequency. Besides, since the LDCB controller shares the same small signal model as that of DCB controller, it achieves similar control loop bandwidth and transient performance. Effectiveness of the proposed LDCB control is verified by zero/pole plots, transient analyses and experimental results.

scholarly journals Fault-Tolerant Control Strategy with Asymmetric Phase Currents for Single to Four-Phase Open-Circuit Faults of Six-Phase PMSM

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3163
Author(s):  
Chen Huang ◽  
Lidan Zhou ◽  
Zujia Cao ◽  
Gang Yao
Keyword(s):  
Working Conditions ◽  
Control Strategy ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Open Circuit ◽  
Time Varying ◽  
Electromagnetic Torque ◽  
Control Loops ◽  
Phase Current ◽  
Multi Phase

Multi-phase motors and generators are regarded with great fault tolerance capability, especially on open-circuit faults. Various mathematics analytical methods are applied for their fault control. In this paper, a fault-tolerant control strategy with asymmetric phase current for the open-circuit faults with arbitrary phases in the six-phase PMSM (six-phase permanent magnetic synchronous motor, 6P-PMSM) system, is proposed for better electrical and dynamical performance of the machine. An innovative mathematical model for PMSM under one to four-phase-open circuit faults are established considering the asymmetry of the machine. Combining with time-varying relations in machines’ working conditions, targeted decoupling transformation matrixes of every kind of open-circuit faults are settled by voltage equations under different faults. Modified control strategy with a connection between the neutral point and the inverter’s DC side is presented, which aims at increasing the system redundancy and reducing the amplitude of phase currents. Besides, improved control loops with two layers are put forward as well, with which the PMSM system acquires fewer harmonics in phase current and smoother electromagnetic torque. Simulation and experimental results of open-circuit faults are provided for verification of the theoretical analysis.

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