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Model predictive control (MPC) schemes employ dynamic models of a process within a receding horizon framework to optimize the behavior of a process. Although MPC has many benefits, a significant drawback is the large computational burden, especially in adaptive and constrained situations. In this paper, a computationally efficient self-tuning/adaptive MPC scheme for a simple industrial process plant with rate and amplitude constraints on the plant input is developed. The scheme has been optimized for real-time implementation on small, low-cost embedded processors. It employs a short (2-step) control horizon with an adjustable prediction horizon, automatically tunes the move suppression (regularization) parameter to achieve well-conditioned control, and presents a new technique for generating the reference trajectory that is robust to changes in the process time delay and in the presence of any inverse response. In addition, the need for a full quadratic programming procedure to handle input constraints is avoided by employing a quasi-analytical solution that optimally fathoms the constraints. Preliminary hardware-in-the-loop (HIL) test results indicate that the resulting scheme performs well and has low implementation overhead.
Michael Short; Fathi Abugchem. A Microcontroller-Based Adaptive Model Predictive Control Platform for Process Control Applications. Electronics 2017, 6, 88 .
AMA StyleMichael Short, Fathi Abugchem. A Microcontroller-Based Adaptive Model Predictive Control Platform for Process Control Applications. Electronics. 2017; 6 (4):88.
Chicago/Turabian StyleMichael Short; Fathi Abugchem. 2017. "A Microcontroller-Based Adaptive Model Predictive Control Platform for Process Control Applications." Electronics 6, no. 4: 88.
In this paper, it is argued that some low-level aspects of the usual IEC 61850 mapping to Ethernet are not well suited to microgrids due to their dynamic nature and geographical distribution as compared to substations. It is proposed that the integration of IEEE time-sensitive networking (TSN) concepts (which are currently implemented as audio video bridging (AVB) technologies) within an IEC 61850 / Manufacturing Message Specification framework provides a flexible and reconfigurable platform capable of overcoming such issues. A prototype test platform and bump-in-the-wire device for tunneling horizontal traffic through AVB are described. Experimental results are presented for sending IEC 61850 GOOSE (generic object oriented substation events) and SV (sampled values) messages through AVB tunnels. The obtained results verify that IEC 61850 event and sampled data may be reliably transported within the proposed framework with very low latency, even over a congested network. It is argued that since AVB streams can be flexibly configured from one or more central locations, and bandwidth reserved for their data ensuring predictability of delivery, this gives a solution which seems significantly more reliable than a pure MMS-based solution.
Michael Short; Fathi Abugchem; Muneeb Dawood. Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection. Energies 2016, 9, 204 .
AMA StyleMichael Short, Fathi Abugchem, Muneeb Dawood. Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection. Energies. 2016; 9 (3):204.
Chicago/Turabian StyleMichael Short; Fathi Abugchem; Muneeb Dawood. 2016. "Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection." Energies 9, no. 3: 204.
Many new demand response strategies are emerging for energy management in smart grids. Real-Time Energy Pricing (RTP) is one important aspect of consumer Demand Side Management (DSM), which encourages consumers to participate in load scheduling. This can help reduce peak demand and improve power system efficiency. The use of Intelligent Decision Support Systems (IDSSs) for load scheduling has become necessary in order to enable consumers to respond to the changing economic value of energy across different hours of the day. The type of scheduling problem encountered by a consumer IDSS is typically NP-hard, which warrants the search for good heuristics with efficient computational performance and ease of implementation. This paper presents an extensive evaluation of a heuristic scheduling algorithm for use in a consumer IDSS. A generic cost model for hourly pricing is utilized, which can be configured for traditional on/off peak pricing, RTP, Time of Use Pricing (TOUP), Two-Tier Pricing (2TP) and combinations thereof. The heuristic greedily schedules controllable appliances to minimize smart appliance energy costs and has a polynomial worst-case computation time. Extensive computational experiments demonstrate the effectiveness of the algorithm and the obtained results indicate the gaps between the optimal achievable costs are negligible.
Chris Ogwumike; Michael Short; Fathi Abugchem. Heuristic Optimization of Consumer Electricity Costs Using a Generic Cost Model. Energies 2015, 9, 6 .
AMA StyleChris Ogwumike, Michael Short, Fathi Abugchem. Heuristic Optimization of Consumer Electricity Costs Using a Generic Cost Model. Energies. 2015; 9 (1):6.
Chicago/Turabian StyleChris Ogwumike; Michael Short; Fathi Abugchem. 2015. "Heuristic Optimization of Consumer Electricity Costs Using a Generic Cost Model." Energies 9, no. 1: 6.
The use of wireless communications for real-time control applications poses several problems related to the comparatively low reliability of the communication channels. This paper is concerned with adaptive and predictive application-level strategies for ameliorating the effects of packet losses and burst errors in industrial sampled-data Distributed Control Systems (DCSs), which are implemented via one or more wireless and/or wired links, possibly spanning multiple hops. The paper describes an adaptive compensator that reconstructs the best estimates (in a least squares sense) of a sequence of one or more missing sensor node data packets in the controller node. At each sample time, the controller node calculates the current control, and a prediction of future controls to apply over a short time horizon; these controls are forwarded to the actuator node every sample time step. A simple design method for a digital Proportional Integral Derivative (PID)-like adaptive controller is also described for use in the controller node. Together these mechanisms give robustness to packet losses around the control loop; in addition, the majority of the computational overhead resides in the controller node. An implementation of the proposed techniques is applied to a case study using a Hardware in the Loop (HIL) test facility, and favorable results (in terms of both performance and computational overheads) are found when compared to an existing robust control method for a DCS experiencing artificially induced burst errors.
Michael Short; Fathi Abugchem; Usama Abrar. Dependable Control for Wireless Distributed Control Systems. Electronics 2015, 4, 857 -878.
AMA StyleMichael Short, Fathi Abugchem, Usama Abrar. Dependable Control for Wireless Distributed Control Systems. Electronics. 2015; 4 (4):857-878.
Chicago/Turabian StyleMichael Short; Fathi Abugchem; Usama Abrar. 2015. "Dependable Control for Wireless Distributed Control Systems." Electronics 4, no. 4: 857-878.
In this letter, processor speedup analysis is used to strengthen recent results regarding the suboptimality of uniprocessor nonpreemptive earliest deadline first (npEDF) scheduling. The suboptimality of npEDF is defined as the minimum amount of increase in the processor speed that is needed to guarantee the npEDF schedulability of any feasible task set. We show that any preemptively schedulable task set that is not schedulable by npEDF will become schedulable on a processor speeded up by a factor of not more than one plus the value of the largest execution requirement divided by the shortest relative deadline of any task. This reduces the pessimism compared to the best previous bound by factor of at least two. In addition, for the case of nonpreemptive Fixed Priority scheduling, we also show that twice this speedup bound is enough to guarantee the schedulability of any feasible task set.
Fathi Abugchem; Michael Short; Donglai Xu. A Note on the Suboptimality of Nonpreemptive Real-time Scheduling. IEEE Embedded Systems Letters 2015, 7, 69 -72.
AMA StyleFathi Abugchem, Michael Short, Donglai Xu. A Note on the Suboptimality of Nonpreemptive Real-time Scheduling. IEEE Embedded Systems Letters. 2015; 7 (3):69-72.
Chicago/Turabian StyleFathi Abugchem; Michael Short; Donglai Xu. 2015. "A Note on the Suboptimality of Nonpreemptive Real-time Scheduling." IEEE Embedded Systems Letters 7, no. 3: 69-72.