1,721,034 research outputs found
Performance comparison between PID, PIDD2 and PIDD2α
No full textWe evaluate the performance achievable with Proportional-Integral-Derivative fractional Double-Derivative controllers, denoted as PIDD2α, by comparing it with that achievable with standard PID controllers and with Proportional-Integral-Double-Derivative (PIDD or PIDD2) controllers, which are also called Proportional-Integral-Derivative-Acceleration (PIDA) controllers. The cost-effectiveness ratio improvement obtained when augmenting the control law with an element proportional to the fractional second derivative of the control error is assessed by considering different process transfer functions and by tuning the controllers minimizing the integrated absolute error with genetic algorithms. Further, a constraint on the maximum sensitivity is also posed so that the system robustness is taken into account. The set-point following and the load disturbance rejection tasks are evaluated separately
On the implementation of gain scheduling in FOPID controllers
No full textThis paper deals with the implementation of a gain scheduling technique for fractional-order-proportional-integral-derivative (FOPID) controllers. The presence of fractional-order integer and derivative parts requires special considerations when the controller parameters are changed during the control task due to the initialization issue of the fractional operators when the fractional order changes. Simulation results show the effectiveness of the proposed technique
A comparison between PID and PIDA controllers
No full textIn this paper we analyze the performance that can be achieved by means of Proportional-Integral-Derivative-Acceleration (PIDA) controllers and we compare it with that achievable by means of PID controllers in order to evaluate the cost/benefit ratio when an action proportional to the second derivative of the control error is added to the control law. In particular, different process transfer functions are considered and the tuning of the controllers is determined with genetic algorithms by minimizing the integrated absolute error. Both the set-point following and load disturbance rejection tasks are evaluated. In order to provide a fair comparison, a constraint on the maximum sensitivity is also posed so that the achieved robustness is taken into account
Imputation accuracy is robust to cattle reference genome updates
No full textGenotype imputation is routinely applied in a large number of cattle breeds. Imputation has become a need due to the large number of SNP arrays with variable density (currently, from 2900 to 777 962 SNPs). Although many authors have studied the effect of different statistical methods on imputation accuracy, the impact of a (likely) change in the reference genome assembly on imputation from lower to higher density has not been determined so far. In this work, 1021 Italian Simmental SNP genotypes were remapped on the three most recent reference genome assemblies. Four imputation methods were used to assess the impact of an update in the reference genome. As expected, the four methods behaved differently, with large differences in terms of accuracy. Updating SNP coordinates on the three tested cattle reference genome assemblies determined only a slight variation on imputation results within method
Analysis of the performance achievable with a PIDD2α controller for depth of hypnosis in total intravenous anesthesia
No full textIn this paper we use a population-based approach to design a fractional-order Proportional-Integral-Double-Derivative (PIDD2α) controller for Depth-of-Hypnosis (DoH) in general anesthesia. In particular, we consider the control problem of achieving and keeping the bispectral index (BIS) at the required value by manipulating the infusion rate of the propofol drug. The performance of the controller is then analyzed and compared with that achieved with a Proportional-Integral-Derivative (PID) and a Proportional-Integral-Derivative-Acceleration (PIDA) controller. Results show that, with the considered design methodology, the improvement obtained by using a fractional-order double-derivative action is marginal and does not justify the increment of the complexity in the controller implementation
Generalized Haalman tuning of PIDA controllers
Full text linkIn this paper we propose a new tuning methodology for Proportional-Integral-Derivative-Acceleration (PIDA) controllers. First, a third-order-plus-dead-time transfer function of the (high-order) process is estimated by evaluating an open-loop step response. Then, the three time constants of the controller are determined by applying a pole-zero cancellation approach and the proportional gain is finally adjusted in order to obtain a desired maximum sensitivity. The controller filters are selected in order to minimize the effects of the measurement noise and to avoid kicks in the control variable. Simulation results show the effectiveness of the methodology in comparison with PID control
A Reduced-Order Digital Twin FPGA-Based Implementation With Self-Awareness Capabilities for Power Electronics Applications
No full textDeveloping accurate mathematical or data-driven models for effective controller design under dynamic variable conditions becomes increasingly challenging. For this reason, the concept of a digital twin (DT) as a virtual representation of a physical asset has been introduced as a tool for process modelling, design, and control implementation while providing additional knowledge of the system that can be used to enable awareness capabilities on the asset. However, digital twin models used to be complex, requiring expensive computational times depending on the application to provide the most accurate system representation, limiting its application in edge, embedded, and register transfer level computing domains. Therefore, using reduced-order digital twin models is an alternative to get DT closer to the physical asset. Considering these challenges, we propose a reduced-order FPGA-based digital twin implementation that directly sources data from the real system, operates in parallel with the virtual system, and enables awareness mechanisms to improve the system's operation. This setup removes large data transfers, cloud interfaces and expensive computational times deriving into a faster and more efficient DT. To illustrate the capabilities of this embedded digital twin, we present a case study focused on monitoring a power converter. The study involves establishing and enforcing a safe operating area (SOA) for the power converter, implementing error awareness mechanisms, and enabling machine learning models to predict converter load conditions and fault events detection. Thus, we aim to showcase the effectiveness of our proposed FPGA-based digital twin approach in addressing real-time control challenges towards smart control engineering
PIDA control of depth of hypnosis in total intravenous anesthesia
Full text linkIn this paper we discuss the use of a Proportional-Integral-Derivative-Acceleration (PIDA) controller for the Depth-of-Hypnosis (DoH) control in total intravenous anesthesia (TIVA). In particular, the infusion rate of the hypnotic drug propofol is the control variable and the bispectral index (BIS) is the controlled variable. The PIDA controller is tuned by using a population-based approach and its robustness is evaluated with a Monte Carlo method. The noise amplification is reduced by means of suitably designed low-pass filters. A comparison with a PID controller is performed, showing that the addition of the acceleration action allows us to design a more aggressive controller, thus reducing the risk of awareness of the patient in the maintenance phase
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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