scholarly journals Double-Loop Control Structure for Rotary Drum Granulation Loop

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1423
Author(s):  
Ludmila Vesjolaja ◽  
Bjørn Glemmestad ◽  
Bernt Lie
Keyword(s):  
Control Structure ◽  
Control Strategies ◽  
Double Loop ◽  
The Novel ◽  
Loop Control ◽  
Process Dynamics ◽  
Oscillatory Systems ◽  
Novel Approach ◽  
Highly Oscillatory ◽  
Highly Oscillatory Systems

The operation of granulation plants on an industrial scale is challenging. Periodic instability associated with the operation of the granulation loop causes the particle size distribution of the particles flowing out from the granulator to oscillate, thus making it difficult to maintain the desired product quality. To address this problem, two control strategies are proposed in this paper, including a novel approach, where product-sized particles are recycled back to maintain a stable granulation loop process. A dynamic model of the process that is based on a population balance equation is used to represent the process dynamics. Both of the control strategies utilize a double-loop control structure that is suitable for highly oscillatory systems. The simulation results show that both control strategies, including the novel approach, are able to remove the oscillating behaviour and stabilize the granulation plant loop.

scholarly journals Comparison of Feedback Control Strategies for Operation of Granulation Loops

2021 ◽  
Vol 50 (4) ◽  
pp. 736-751
Author(s):  
Ludmila Vesjolaja ◽  
Bjørn Glemmestad ◽  
Bernt Lie
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Fine Particles ◽  
Control Strategies ◽  
Pi Controller ◽  
Oscillatory Behavior ◽  
Double Loop ◽  
Oscillatory Behaviour ◽  
Loop Control ◽  
Median Diameter

Granulation is a particle enlargement process during which fine particles or atomizable liquids are converted into granules via a series of complex granulation mechanisms. In this paper, two feedback control strategies are implemented to make granulation loop processes more steady to operate, i.e., to suppress oscillatory behavior in the produced granule sizes. In the first control strategy, a classical proportional-integral (PI) controller is used, while in the second, a double-loop control strategy is used to control the median diameter of the granules leaving the granulator. The simulation results showed that using the proposed control design for the granulation loop can eliminate the oscillatory behaviour in the produced granule median diameter and make granulation loop processes more steady to operate. A comparison between the two proposed control strategies showed that it is preferable to use the double-loop control strategy.

Design and simulation of a novel FOIMC-PD/P double-loop control structure for CSTRs and bioreactors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shweta Kumari ◽  
Pulakraj Aryan ◽  
G. Lloyds Raja
Keyword(s):  
Fractional Order ◽  
Closed Loop ◽  
Nonlinear Models ◽  
Control Strategies ◽  
Process Models ◽  
Tuning Parameter ◽  
Double Loop ◽  
Outer Loop ◽  
Loop Control ◽  
Inverse Response

Abstract The design of control methods for unstable plants is somewhat complex than that of stable plants. This is because unstable process models contain one or more poles lying on the right of the s-plane which yields unbounded closed-loop response. Further, the presence of the dead-time induces more complexity as it decreases the gain and phase margins which in turn deteriorates the closed-loop performance. The design of control strategies become more challenging for plants of unstable nature with positive zeros because they exhibit a phenomenon called inverse response. This paper suggests a method to design a double-loop scheme for unstable plants with/without inverse response. Accordingly, a proportional-derivative (PD)/proportional (P) controllers are used in the inner-loop for stabilizing the plant. A fractional order internal model controller (FOIMC) scheme is used to obtain the outer-loop controller using the stabilized plant model. The P/PD controller settings have been obtained by using the Routh-stability criteria and the maximum sensitivity approach. Procedure for selecting the outer-loop tuning parameter and fractional order is also given. Linear and nonlinear models of unstable plants including bioreactors and isothermal chemical reactors are used to demonstrate the merits of the suggested strategy. Robustness of the design and effect of measurement noise are also studied. Integrated absolute/squared error measures are also calculated. The suggested design is found to be more effective in controlling unstable processes than some reported works.

Microassembly via Coordinated Manipulation of Objects Using a Multifingered Micromanipulator

2011 ◽  
Author(s):  
Christopher Pelzmann ◽  
Laxman Saggere
Keyword(s):  
Closed Loop ◽  
State Of The Art ◽  
Control Strategies ◽  
Open Loop ◽  
Open Loop Control ◽  
Multiple Objects ◽  
Loop Control ◽  
Micro Scale ◽  
Novel Approach ◽  
On Chip

This paper presents a novel approach to manipulation and assembly of micro-scale objects using a chip-scale multi-fingered micromanipulator, in which multiple, independently controlled compliant fingers coordinate with each other to grasp and manipulate multiple objects simultaneously on-chip. The structural and functional advantages of this multi-fingered micromanipulator in achieving high dexterity in a compact form as compared to other state-of-the-art manipulation tools are discussed. A formulation of the kinematics of the manipulator’s compliant fingers along with two different control strategies including an operator-driven closed-loop control and a semi-autonomous open-loop control for coordinated manipulation and on-chip assembly of micro-scale objects are introduced. Finally, the details of implementation of both control strategies and successful experimental demonstration of manipulations and assembly of two interlocking micro-scale parts with sub-micron mating clearance using the multifingered manipulator are presented.

Sign in / Sign up

Export Citation Format

Share Document