Showing papers by "Kishore Bingi published in 2017"

Adopting Setpoint Weighting Strategy for WirelessHART Networked Control Systems Characterised by Stochastic Delay

Abstract: In networked control system, such as WirelessHART that is characterized by stochastic delay, the use of proportional integral and differential (PID) controllers is inadequate. This is because PID performs poorly in handling time-delay processes. The main reason for this poor performance is the limitation in the range of stable gain of the controller. Time delay causes oscillatory response of the PID with large gain. Likewise, sluggish response is experienced with small gain of the PID. Also, dead time compensators like smith predictor and internal model controller are difficult to be implemented practically since they require exact model of the process to be controlled. Therefore, this paper proposes the application of setpoint weighting strategy to be used alongside PID controller in a WirelessHART network. This method extends significantly the range of the PID gain, while providing good set point tracking and load regulation. From the simulation and experimental results obtained, the capability of the approach to load regulation and tracking can be seen in its fast recovery from effect of disturbance with minimal overshoot. Thus, a two degree of freedom control is achieved. Results also showed that the method is robust to real-time random variable network delay and model mismatches.

Fuzzy gain scheduled set-point weighted PID controller for unstable CSTR systems

Abstract: Control of CSTR process has been challenging due to highly nonlinear and dynamic behavior. Furthermore, the CSTR processes are unstable. The use of PID controllers for such processes has been attempted. However, poor performance is obtained due to limitations of the PID controllers. On the other hand, using heuristic algorithms to tune the controllers only gives optimal performance for a restricted range of parameter variations. This paper proposes the use of fuzzy gain scheduling (FGS) adaptation mechanism to tune set-point weighted PID controller for the CSTR process. The result of comparison from the simulation performed showed that proposed method achieved better set-point tracking and disturbance rejection compared to the FGS-PID controller.

Robustness and Stability Analysis of a Predictive PI Controller in WirelessHART Network Characterised by Stochastic Delay

Abstract: As control over wireless network in the industry is receives increasing attention, its application comes with challenges such as stochastic network delay. The PIDs are ill equipped to handle such challenges while the model based controllers are complex. A settlement between the two is the PPI controller. However, there is no certainty on its ability to preserve closed loop stability under such challenges. While classical robustness measures do not require extensive uncertainty modelling, they do not guarantee stability under simultaneous process and network delay variations. On the other hand, the model uncertainty measures tend to be conservative. Thus, this work uses extended complementary sensitivity function method which handles simultaneously those challenges. Simulation results shows that the PPI controller can guarantee stability even under model and delay uncertainties.

Design of FIR filter using novel pipelined bypass multiplier

Abstract: The vigorous growth in portable multimedia devices and communication system has increased the demand for area and power efficient high-speed Digital Signal Processing (DSP) system. Usage of digital Finite Impulse Response (FIR) filter is one of the prime block in DSP. Digital multipliers and adders are the most critical arithmetic functional units in FIR filters and also decides the performance of whole system. This research proposes a novel pipelined architecture of high-speed bypass multiplier which utilizes the bypassing method to minimize the switching activities and incorporates novel pipelining technique for improving its performance. Low-power and area-efficient register using pulsed latches added instead of flip-flops in the novel pipelining technique. A comparison between various bypass multipliers with pipeline in terms of delay, power and area utilization were also done in this work. Carry-Look ahead Adder (CLA) is used for addition operation which uses fastest carry generation technique to increases speed by reducing the time required to fix carry bits in ripple carry adder. By employing the proposed novel pipelined high-speed bypass multiplier and carry-look ahead adder, a digital FIR filter with length of 8-tap and 16-tap has been designed which results in a delay reduction of 52% and 33.2% respectively over the conventional method. Similarly, the power consumption analysed for the 8-tap and 16-tap FIR Filter circuit and obtained power saving of 39.7% and 28.7% respectively with reduction in area of 12.1% and 20.4% respectively is better compared to the non-pipelined technique.

Development of WirelessHART adapter with industrial transmitter for process monitoring

Abstract: The advancement of wireless technology is becoming more apparent in industrial sectors with the advent of standards such as WirelessHART. The benefits associated with WirelessHART includes elimination of costly and cumbersome cabling, reduced maintenance cost and reduced deployment, redeployment in the network. However, the current WirelessHART is lack of low cost adapter for monitoring and control application in process industries. In this work, a low cost WirelessHART adapter is developed using a mote and microcontroller (Arduino Mega 2560) for process monitoring application. Experimental results with temperature transmitter shows that the developed adapter is successfully interfaced and the temperature data is monitored continuously at a satisfactory delay.

Signal noise filter structure selection for predictive PI controller in a wireless networked control setting

Abstract: The predictive proportional integral (PPI) controller being simple and non conservative like its Smith predictor and internal model control (IMC) counterparts, has the ability to be employed in environments characterised by uncertainties such as stochastic network delays. However, its performance degrades in the presence of measurement noise. This is due to the prediction involve in the controller which acts like the derivative term of PID controller that amplifies high frequency noise. This necessitated the need for additional filtering of the noisy signals. Therefore, this work proposes three several filter configurations for PPI controller in a wireless environment. Simulation results shows that placing the filter within the PPI controller gives smooth control signal that can yield better control performance compared to both feedback and cascade filter configurations.

Spiral dynamic algorithm based optimal PPI controller for WirelessHART networked systems

Abstract: The Predictive PI controller is considered a viable candidate to replace conventional PID for WirelessHART networked control system (WHNCS). This is due to its shared characteristics of simplicity and ease of manual tuning while allowing for mismatches and improved performance even in the presence of stochastic delay. However, in order to avoid excessive overshoots and oscillations due to the stochastic delay, the parameters of this controller need to be tuned. Therefore, this paper presents the use of simple but efficient nature inspired spiral dynamic algorithm (SDA) to tune the parameters of the PPI controller designed for WHNCS. Simulation results showed that the SDA-tuned PPI controller outperformed the compared PPI and PID controllers in terms of overshoot, disturbance rejection and smooth control signals for both first and second order plants considered. Furthermore, the proposed controller settles faster than the other controllers both before and after disturbance. Hence, the SDA-tuned PPI controller has the potential of improving systems control performance.

Fuzzy Adaptive Setpoint Weighting Controller for WirelessHART Networked Control Systems

Abstract: Gain range limitation of conventional proportional-integral-derivative (PID) controllers has made them unsuitable for application in a delayed environment. These controllers are also not suitable for use in a Wireless Highway Addressable Remote Transducer (WirelessHART) protocol networked control setup. This is due to stochastic networkinduced delay and uncertainties such as packet dropout. The use of setpoint weighting strategy has been proposed to improve the performance of the PID in such environments. However, the stochastic delay still makes it difficult to achieve optimal performance. This chapter proposes an adaptation to the setpoint weighting technique. The proposed approach will be used to adapt the setpoint weighting structure to variation in WirelessHART network-induced delay through fuzzy inference. Result comparison of the proposed approach with both setpoint weighting and proportional-integral (PI) control strategy shows improved setpoint tracking and load regulation. For the first-, secondand third-order systems considered, analysis of the results in the time domain shows that in terms of overshoot, undershoot, rise time, and settling times, the proposed approach outperforms both the setpoint weighting and the PI controller. The approach also shows faster recovery from disturbance effect.

Real-time model predictive control for nonlinear gas pressure process plant

Abstract: Nonlinear behaviour of the systems happens to be a common problem in industrial processes. They cause a large amount of time, resources and efforts to be utilized in order to deal with them. A Major hurdle in Nonlinear Industrial Processes is system modeling. Due to this reason, several methods and techniques have been designed and developed in order to improve the overall control performance in industrial process control. Model based controllers have been developed and implemented on various applications with promising results. Their main benefit is they can identify and tune unknown system parameters in real-time. This paper focuses on real-time controller development and its implementation on Gas Pressure Process Plant using MPC. MPC is considered to be one of the robust and effective controllers due to impressive control performance in different applications previously. MPC makes use of a model for system identification and based upon that, it can dynamically send next control move for the system. This research work incorporates State-Space Model for unknown system-parameter identification. The identified parameters will be utilized by MPC for control law development. The proposed methodology is validated by real-time experimental results on the aforementioned system.