Industrial Control Applications Research Articles

Adaptive Model Recovery Anti-Windup for Output-Feedback Plants

The control of real technical systems always involves consideration of maximal input amplitudes. Moreover, the properties of technical systems often change during their lifetime, due to e.g. aging or small defects. In order to satisfy high performance requirements for the whole duration of such systems, the use of adaptive control is beneficial. Since for many industrial control application, e.g. in automotive industry, only the output of systems is measurable, an output-feedback adaptive controller is necessary, which is able to deal with input saturation. A new adaptive method based on model recovery anti-windup (MRAW) for continuous time systems is presented in this work. It allows for performance considerations in the case of input saturation. Results of boundedness for the closed-loop system are shown and verified with a simulation example. The simulation example shows the benefits of the adaptive control scheme with anti-windup in comparison to a robust approach in the presence of parameter uncertainties.

Investigation of Bucket Wheel Excavator Lattice Structure Internal Stress in Harsh Environment through a Remote Measurement System

The paper shows the results of a lab model for strain gauges based measuring system for multiple measuring heads of the mechanical stress in lattice structures of the bucket wheel excavator for open pit mines-harsh environment. The system is designed around a microcontroller system. Because of specific working conditions, the measuring system sends data to a processing system (a PC with Matlab software), we have implemented a secure communication solution based on ISM standard, by using NRF24L01 module. The transceiver contains a fully integrated frequency synthesizer based on crystal oscillator, and a Enhanced ShockBurst™ protocol engine. The proposed solution has a current consumption around 9.0 mA at an output power of −6dBm and 12.3mA in RX mode. Built-in Power Down and Standby modes makes power saving easily realizable for our solution battery powered. The stress from structures is taken by specific strain gauges adapted to low frequency vibrations. We are using a precision 24-bit analog-to-digital converter (ADC) designed for weigh scales and industrial control applications to interface directly with a bridge sensor-instrumentation device, with low drift voltage, low noise, common mode rejection signal, frequency and temperature stability. As backup implementation for measurements a high speed storage implementation is used.

A Study of FPGA-based System-on-Chip Designs for Real-Time Industrial Application

This paper shows the benefits of the Field Programming Gate Array (FPGAs) in industrial control applications. The author starts by addressing the benefits of FPGA and where it is useful. As well as, the author has done some FPGA’s evaluation researches on the FPGA performing explaining the performance of the FPGA and the design tools. To show the benefits of the FPGA, an industrial application example has been used. The application is a real-time face detection and tracking using FPGA. Face tracking will depend on calculating the centroid of each detected region. A DE2-SoC Altera board has been used to implement this application. The application based on few algorithms that filter the captured images to detect them. These algorithms have been translated to a Verilog code to run it on the DE2-SoC board

Novel control algorithm for MPPT with Boost converters in photovoltaic systems

The great advances in efficiency and performance of photovoltaic modules would not be very useful if they do not work close to their maximum power point (MPP). In this paper a novel Sliding Mode Control (SMC) based algorithm is proposed to be implemented in a DC/DC converter in order to make an autonomous photovoltaic system to work at the MPP. Once that the design of the novel algorithm has been detailed (especially the novel part relative to the current reference signal) and its stability has been demonstrated, its performance has been compared with two of the most commonly used algorithms in this scope, i.e., Perturbation & Observation (P&O) and Incremental Conductance (IC) algorithms, in addition to a PI controller because it is one of the preferred controllers in industrial applications. This comparison has been carried out taking into account both simulated and experimental tests. The first focused on their behavior when sudden changes in irradiance and temperature, while the lasts analyzed them when the load resistance was varying arbitrarily in actual facilities (composed of a photovoltaic module Mitsubishi PV-TD185MF5, a Boost converter, a variable load and a real-time data acquisition card dSPACE DSP1104 used as the interface between the control algorithm implemented in Simulink/Matlab and the real photovoltaic module). After completing tests under different conditions, we found that the proposed SMC based algorithm outperforms the PI controller and the P&O and IC algorithms, especially in experiments carried out using actual facilities.

From single to many-objective PID controller design using particle swarm optimization

Proportional, integrative and derivative (PID) controllers are among the most used in industrial control applications. Classical PID controller design methodologies can be significantly improved by incorporating recent computational intelligence techniques. Two techniques based on particle swarm optimization (PSO) algorithms are proposed to design PI-PID controllers. Both control design methodologies are directed to optimize PI-PID controller gains using two degrees-of-freedom control configurations, subjected to frequency domain robustness constraints. The first technique proposes a single-objective PSO algorithm, to sequentially design a two degrees-of-freedom control structure, considering the optimization of load disturbance rejection followed by set-point tracking optimization. The second technique proposes a many-objective PSO algorithm, to design a two degrees-of-freedom control structure, considering simultaneously, the optimization of four different design criteria. In the many-objective case, the control engineer may select the most adequate solution among the resulting optimal Pareto set. Simulation results are presented showing the effectiveness of the proposed PI-PID design techniques, in comparison with both classic and optimization based methods.

Programmable Automation Controller Mechatronic Experiment

This paper describes the use of the OPTO-22 Programmable Automation Controller (PAC) Learning center in the undergraduate control systems course at California State Polytechnic University at Pomona (Cal Poly Pomona). The OPTO-22 PAC System is an integrated system of hardware and software used for industrial control, remote monitoring, and data acquisition applications. The paper compares the pros and cons of using a PAC versus Programmable Logic Controller (PLC) or Field Programmable Gate Array (FPGA) systems. The paper introduces the flowchart based programming environment used in PACs. The paper includes an illustrative example of how the OPTO-22 PAC system can be interfaced to an industrial based Mechatronics pick-and-place robot station. This example details the input/output interfaces of the OPTO-22 PAC unit and the SUN Equipment Mecahtronics pick and place robot unit. Details of the flow chart programming and I/O interfacing protocols are given in the paper. The I/O configuration dialog in the OPTO-22 PAC development environment are also presented in this paper.

Marker assay guided standardization of an ayurvedic concentrated polyherbal decoction “CiruvilvāDi KaṣāYam” and its application in industrial quality control

Background: To establish a marker guided standardization technique to assess whether the marketed concentrated kaṣāyam (decoction) prepared in large scale is providing the same phytochemical values of a Laboratory Reference Standard (LRS) kaṣāyam prepared classically from raw materials of Pharmacopoeial quality. Objectives: Manufacturing and standardization of LRS ' Ciruvilvādi kaṣāyam' , including marker assays and its comparison with four different marketed samples. Materials and Methods: pH, Brix and Total solids of samples were determined and compared. HPTLC profile comparison and quantitative comparison with HPLC were done with Gallic acid and Piperine as standards. Results and Conclusion: Results of Brix and Total solids imply that, the manufacturing process of sample IV was significantly different from other samples and LRS. pH value of sample III showed a significant difference as compared to other samples and LRS, indicating a difference in phytochemical contents. Quantification of Piperine and Gallic acid revealed that sample III has a very low Gallic acid concentration and zero Piperine concentration. Sample IV showed a very high concentration of Gallic acid when compared to other samples and LRS. Sample I, II and IV had piperine content but significantly lower when compared to the LRS. In conclusion, the samples (1-IV) which showed difference with the LRS should be made phytochemically comparable to in-house LRS or Pharmacopoeial standards by adopting the marker assay standardization technique. This method helps to identify and rectify the problems related to raw material, in process and finished product quality control.

Cross-Layer Optimization for Industrial Control Applications Using Wireless Sensor and Actuator Mesh Networks

When multiple control processes share a common wireless network, the communication protocol must provide reliable performance in order to yield stability of the overall system. In this paper, the novel cross-layer optimized control (CLOC) protocol is proposed for minimizing the worst case performance loss of multiple industrial control systems. CLOC is designed for a general wireless sensor and actuator network where both sensor to controller and controller to actuator connections are over a multihop mesh network. The design approach relies on a constrained max-min optimization problem, where the objective is to maximize the minimum resource redundancy of the network and the constraints are the stability of the closed-loop control systems and the schedulability of the communication resources. The optimal operation point of the protocol is automatically set in terms of the sampling rate, scheduling, and routing, and is achieved by solving a linear programming problem, which adapts to system requirements and link conditions. The protocol has been experimentally implemented and evaluated on a testbed with off-the-shelf wireless sensor nodes, and it has been compared with a traditional network design and a fixed-schedule approach. Experimental results show that CLOC indeed ensures control application stability and fulfills communication constraints while maximizing the worst case redundancy gain of the system performance.

Damping properties of para-phenylene terephthalamide pulps modified damping materials

A series of para-phenylene terephthalamide pulp modified damping materials were prepared. The dynamic mechanical properties, differential scanning calorimetry, vibration damping properties, vulcanization property, tensile strengths as well as scanning electron microscopy micrographs of the damping materials were studied theoretically and experimentally. The dynamic mechanical properties of para-phenylene terephthalamide pulp modified damping materials were also compared with aramid short-cut fiber, E-glass staple fiber and carbon fiber powder modified damping materials. The results showed that para-phenylene terephthalamide pulp modified damping materials exhibited the best damping property and highest modulus in comparison with the other types of fibers. The storage modulus ( E′), loss modulus ( E″) and tensile strength of the materials were all increased significantly with increasing pulp content, and this trend was significantly greater in machine direction rather than in cross-machine direction. The second, third and fourth modes modal loss factors (η) of the steel beams coated with para-phenylene terephthalamide pulp modified damping materials increased substantially up to a maximum, and then became stable with increasing pulp amount. The optimal η in machine direction was achieved as the mass ratio of butadiene-acrylonitrile rubber to para-phenylene terephthalamide pulp was 100:30. Excellent damping property was mainly attributed to the extremely high interfacial contact area which significantly improved the efficiency of energy dissipation of internal friction, interfacial sliding and dislocation motion between para-phenylene terephthalamide pulps and butadiene-acrylonitrile rubber chains. Since para-phenylene terephthalamide pulp modified damping materials offer a high E′, excellent vibration damping properties, broad damping temperature and frequency ranges, it is ideal for free-damping structures which are widely utilized in industrial vibration and noise control applications.

PI Controller Performance Analysis Using Lambert W Function Approach for First Order Systems with Time Delay

Time delays are inherent in process industry. The presence of time delays limits and degrades the possible performance of the system and also leads to instability. The states of the delay system not only depend on the present state, they also depend on the previous states. With the help of a suitable controller design, the delay systems can be controlled for getting fruitful results. In all industrial feedback control applications most commonly and practically used controllers are Proportional Integral Derivative (PID) controllers. With proper parameter tuning of the controller, required performance can be achieved from the system. In general, the first order processes with time delay can be easily controlled with PI controllers. By choosing the proper controller gains the effect of time delays can be avoided. In this paper, PI controller design with Lambert W function analysis in smith configuration has been proposed. After the selection of dominant poles, the PI controller gains were chosen accordingly to shift the desired eigen values to required positions using the Lambert W function based analysis. A first order process with time delay has been considered in this paper and the comparative analysis of proposed tuning algorithm with Smith predictor (SP) and Zeigler-Nichols (ZN) methods has been done. By using the time response performance specifications and errors, the performance of different tuning algorithms has been analyzed. From the simulation and different performance indices results, it has been observed that proposed smith configured Lambert W based controller tuning approach gives improved results compared to remaining methods in terms of the measures like overshoot, peak time, settling time, rise time, errors etc.

Fuzzy Based Real Time Control of Induction Motor Drive

Due to advancement in power electronics and micro computing, the control of the induction machines has considerable development that lead to the possibility of high performance real time implementation. The most popular algorithm for the control of a three-phase induction motor is the v/f control approach using a natural Pulse-Width Modulation PWM) technique to drive a Voltage Source Inverter (VSI). But the performance of electric drives requires decoupled torque and flux control. The most widely used controllers in industrial applications are PI controllers because of their simple structure and good performance in a wide range of operating conditions. PI and Fuzzy Logic controllers have been designed and developed using MATLAB/SIMULINK. Prototype model is developed to validate the effectiveness of the PI and Fuzzy control of induction motor drive using dSPACE DS1104 controller. The performance of the SVPWM based induction motor in open loop and closed loop is presented with simulation. Fuzzy Logic (FL) and Conventional PI controllers have been practically implemented using SVPWM based VSI fed induction motor in open loop mode. The real time performance of Fuzzy based induction motor is presented by validating simulation results with the hardware results.

Cost-Oriented Open Source Automation Potential Application in Industrial Control Applications

Abstract: One of the most cost effective ways to make system control (automation) is by using open source hardware and software, in order to be cost oriented besides the price the systems need to be implemented in reasonable time frame and also needs to be reliable and safe. In this paper we will treat and justify the cases of using the Open Source Hardware and Software, in comparison to industry standard Programmable Logic Controllers (PLC). Also we will discuss about the point of system complexity where the cost reduction will not justify the time spend to build the interfacing of sensors, digital and analog I/O for the open source Hardware.

Model-Free Predictive Control of Nonlinear Processes Based on Reinforcement Learning

Abstract Model predictive control (MPC) is a model-based control philosophy in which the current control action is obtained by on-line optimization of objective function. MPC is, by now, considered to be a mature technology owing to the plethora of research and industrial process control applications. The model under consideration is either linear or piece-wise linear. However, turning to the nonlinear processes, the difficulties are in obtaining a good nonlinear model, and the excessive computational burden associated with the control optimization. Proposed framework, named as model-free predictive control (MFPC), takes care of both the issues of conventional MPC. Model-free reinforcement learning formulates predictive control problem with a control horizon of only length one, but takes a decision based on infinite horizon information. In order to facilitate generalization in continuous state and action spaces, fuzzy inference system is used as a function approximator in conjunction with Q-learning. Empirical study on a continuous stirred tank reactor shows that the MFPC reinforcement learning framework is efficient, and strongly robust.

Dynamic Spectrum Access Integrated in a Wideband Cognitive RF-Ethernet Bridge for Industrial Control Applications

In this paper the integration of a Dynamic Spectrum Access (DSA) technique in a wideband cognitive RF-Ethernet bridge for industrial control applications is presented. The proposed DSA scheme is based on two spectrum sensing algorithms and it allows avoiding any possible interference due to external communication systems or industrial equipments. Thus, the bridge is capable of carrying out an interference-free communication, providing the reliability and robustness required by industrial control applications. It also enables to expand a wired network to places where it is not possible to route a wire (such as moving or rotating elements) or replacing a wired link by a wireless one reducing maintenance and deployment costs. The RF-Bridge can work in the Industrial Scientific and Medical (ISM) bands of 868 MHz and 2.45 GHz. The FPGA implementation of this bridge is detailed in this contribution, as well as the measurement tests that have been carried out.

面向工业监控应用的广域异构无线网络端到端时延分析

With the development of wireless communication, the wireless communication technologies based on WirelessHART, WIA-PA, and ZigBee are used widely in the industrial control field. However, owing to the con-straint of capital, technology, equipment, etc., diverse network technologies have long coexisted. Delay analysis is an effective method for detecting real-time network properties in the network design phase. Currently, there is no particular method of analyzing end-to-end transmission delay in wide-area industrial heterogeneous networks. Consequently, based on wide-area heterogeneous backhaul networks with industrial control applications, end-toend delay in wide-area heterogeneous environments, including IEEE 802.11 long-distance WIFI, WirelessHART, ZigBee, and WIA-PA, is analyzed theoretically and verified experimentally. These comparative experiments show that, when the node number of an 802.11 long-distance WIFI backhaul network is greater than 25, and the data aggregation period of the gateway is less than 30 ms, the pessimism ratio is guaranteed to be within 2.3 in the network for ZigBee and within 1.5 for others. The rationale and validity of the method are proved.

Total reflection X-ray photoelectron spectroscopy as a semiconductor lubricant elemental analysis method

Photoelectron spectra from a typical hard disk storage media device (HDD) were measured at total reflection and non-total reflection at unburnished, acetone-cleaned, and argon-sputtered conditions. F, O, N, and C usually making the upper layer of a typical hard disk medium were detected. Enhancement of the photoelectron emission of the fluorocarbon lubricant was observed at total reflection. Pt and Co were only found by non-total X-ray photoelectron spectroscopy (XPS) because they are constituents of a deeper region than the top and interface regions. Argon-sputtered, ultrasonic acetone-cleaned, and unburnished top layers were compared at total and non-total reflection conditions. Total reflection X-ray photoelectron spectroscopy (TRXPS) is demonstrated to be a powerful tool for storage media lubrication layer chemical state analysis, reliable for industrial quality control application , and reproducible.

Model free sliding mode stabilizing control of a real rotary inverted pendulum

Inverted pendulum systems, because of highly nonlinear, coupled, and unstable dynamic behaviour, are excellent experimental platforms for testing new developed control algorithms. This study explores nonlinear modelling, simulation and sliding mode stabilizing control of a real rotary inverted pendulum in detail. For simulation purposes only, the system was modelled in a nonlinear state space form including the servomotor dynamics. In the light of the simulation results, a rotary inverted pendulum system was designed and manufactured. For a certain quality level of desired output, benefits of the sliding mode control of the system without using an equivalent control signal by selecting a proper smoothing function were shown. This model free approach can be used to satisfy a need especially for practical control applications in industry to a certain level, encouraging practical control engineers to use sliding mode control, who have no ability to model a system or no sufficient time for this, or encounter very complex nonlinear system models in many cases. Comparisons of the theoretical and experimental results demonstrate that the state equations describe the dynamics of the system satisfactorily, and that robust and accurate balancing of the pendulum can be achieved by using model free sliding mode control with sigmoid smoothing function.

INTEGRATED HANDS-ON AND REMOTE PID TUNING LABORATORY

University control engineering coursesusually focus on Proportional Integral Derivative (PID)controllers. Moreover PID controllers are used in morethan 90% of the industrial control applications, becausethey are relatively cheap, easy to use, and robust enoughfor most industrial applications. However, universityteaching attaches most importance to the theoreticalknowledge of PID controllers, rather than the practicalskills required to support the use of these controllers inindustry. In addition, the cost and space challengesassociated with hands on laboratories make simulationbased laboratories a more attractive option for teachingPID controllers. Unfortunately, simulations do notcapture the complexity of control systems that areimportant to develop the practical skills of students. Inthis paper, we present a laboratory setup that is used toteach practical skills in PID tuning. The system controlsthe temperature of a small fictitious house whosetemperature is affected by an uncontrolled heating sourceand blow fan. The PID data is accessible to the systemuser through OLE( Object Linking & Embedding) forProcess Control, also referred as Open ProcessControl(OPC) technology. This technology allows thesystem to be used as a hands-on or remote laboratory,which allows students to learn the complexity of PIDcontrollers, while removing the time and spaceconstraints imposed by purely hands on laboratories.Being accessible remotely, the setup enables andencourages instructors to include demonstrations of PIDtuning into their lectures

Design and Implementation of Lifecycle Management for Industrial Control Applications

This paper presents an integrated methodology to manage the lifecycle of industrial control applications, which covers the adaptive estimation and iterative optimization of process parameters, as well as the needs for fault diagnosis and continuous monitoring. More specifically, the design philosophy behind this scheme starts with the parameterization of all stabilizing controllers in the residual generator-based form, and then proceeds with the formation of the expandable controller architecture with an integrated residual access. To further implement the methodology, control system parameters are classified functionally with different importance and preemptive priorities. In the end, some experimental studies and comparative evaluation are conducted in the laboratory continuous stirred tank heater process to verify the effectiveness of the proposed scheme.

Optical absorption measurements of hydrogen chloride at high temperature and high concentration in the presence of water using a tunable diode laser system for application in pyrohydrolysis non-ferrous industrial process control.

A tunable diode laser (TDL) was used to measure hydrogen chloride (HCl) spectra at 5747 cm(-1) (1.74 μm) and temperatures of 25-950 °C in a quartz cell. The purpose was to evaluate the capability of monitoring HCl concentration under pyrohydrolysis conditions using a near-infrared (NIR) laser. These conditions are characterized by 20-40% HCl, 2-40% H2O, and the presence of metal chloride vapors at temperatures of 600-1000 °C. Spectral peak area measurements of HCl-N2 mixtures at atmospheric pressure and a path length of 8.1 cm showed linear absorption behavior between concentrations of 5-95% and temperatures of 25-950 °C. Results from the addition of 2-40% water (H2O) indicate that the HCl peak area relationships are not affected for temperatures of 350-950 °C. Evaporating NiCl2 within the cell did not show spectral interference effects with HCl between 650 and 850 °C. The results from this work indicate that a near-infrared optical sensor is capable of measuring high HCl concentrations at high temperatures in the presence of high H2O content during pyrohydrolysis process conditions.