Energy-aware manufacturing operations

This editorial introduces the special issue on energy-aware manufacturing operations in the International Journal of Production Research. The 12 papers in this special issue were selected because of their high quality and also because they deal with topics related to energy-aware manufacturing operations. Three broad challenges are collectively addressed by the papers in this special issue: energy-efficiency vs. manufacturing-system effectiveness in optimisation; the volatility in energy availability, supply and cost; modelling energy consumption in varying scales and across different sub-systems. Previous global discussions about the state of the art in energy-aware manufacturing operations are provided, as well as exploratory guidelines for future research in this area

Just-in-time delivery for green fleets: A feedback control approach

•Dynamic models for controlling vehicle speed and the departure time are developed.•just-in-time and fuel performances are examined for VRPSTW.•Impact of load weight and JIT penalty cost on a routing schedule is examined.•Drivers can flexibly change the routing schedules considering JIT and fuel performance. With increasing attention being paid to greenhouse gas (GHG) emissions, the transportation industry has become an important focus of approaches to reduce GHG emissions, especially carbon dioxide equivalent (CO2e) emissions. In this competitive industry, of course, any new emissions reduction technique must be economically attractive and contribute to good operational performance. In this paper, a continuous-variable feedback control algorithm called GEET (Greening via Energy and Emissions in Transportation) is developed; customer deliveries are assigned to a fleet of vehicles with the objective function of Just-in-Time (JIT) delivery and fuel performance metrics akin to the vehicle routing problem with soft time windows (VRPSTW). GEET simultaneously determines vehicle routing and sets cruising speeds that can be either fixed for the entire trip or varied dynamically based on anticipated performance. Dynamic models for controlling vehicle cruising speed and departure times are proposed, and the impact of cruising speed on JIT performance and fuel performance are evaluated. Allowing GEET to vary cruising speed is found to produce an average of 12.0–16.0% better performance in fuel cost, and −36.0% to +16.0% discrepancy in the overall transportation cost as compared to the Adaptive Large Neighborhood Search (ALNS) heuristic for a set of benchmark problems. GEET offers the advantage of extremely fast computational times, which is a substantial strength, especially in a dynamic transportation environment

Simulation-based control for green transportation with high delivery service

Shipping operations are facing increasing pressures for tighter delivery service levels and green transportation, which conflict with each other and requires trade-off between fuel consumption and delivery service. Furthermore, responsiveness to customer demand requires rapid generation of good quality solutions. This paper presents a simulation-based feedback control algorithm for real-time vehicle route planning which considers delivery timeliness and fuel efficiency. The proposed control theoretic algorithm uses feedback from simulation to adjust the planned routes for timeliness and adaptively adjust the vehicle speed within an allowable range to improve fuel efficiency. The formulation results in a multi-variable continuous variable control system with non-linear dynamics. The control algorithm extends prior work in distributed arrival time control, which is used as a basis to derive analytical insights into this computational intractable optimization problem. Performance of the algorithm is evaluated using a simulation model of an industrial distribution center

Real-time Feedback Control for Production, Maintenance, and Capacity

In this paper, we develop dynamic models for production scheduling, machine maintenance planning, and machine capacity control. Specifically, differential equation based models are used to characterize real-time dynamics that span from controlling machinery capacity to production and maintenance planning. Based on these dynamic models, distributed feedback control algorithm which is performed upon discrete-event simulation using each part's and machine's local information is developed to determine the production and the machine maintenance event scheduling while controlling the machine capacity in a unified manner

A Dynamic Algorithm for Distributed Feedback Control for Manufacturing Production, Capacity, and Maintenance

We propose a dynamic algorithm for distributed feedback control which unifies the functions of production and maintenance scheduling at the shop floor level, and machinery capacity control at the CNC level, which are usually considered in isolation in practice. A continuous-time control theoretic approach is used to model dynamics of these three functions in a unified manner, considering stochastic machine failures and a corresponding maintenance interval. Theories of nonlinear control and discontinuous differential equations are used to analytically predict the system dynamics including the resulting discontinuous dynamics

Engineering Large Event Catering Services

Part 4: Gastronomic Service System DesignInternational audienceIn the United States, catering services constitute about $8.6 billion annually. The main objective in managing large catered events is centered around ensuring good customer satisfaction while minimizing food wastage. Achieving this management objective is challenging because of some of the key characteristics of such service systems such as long setup time, time-varying demand, and complex customer food preferences. Industry practice heavily relies on the experience of individuals with little use of model-driven decision-making for planning such events. This paper takes a service system engineering approach for event catering by developing an analytical framework for decision-making by event planners to determine kitchen capacity, temporary storage capacity for warmers, and staffing level for buffet service. The proposed model is distribution-free and provides intuitive visualization for decision-making. As a practical case study, the model is applied to a large catered event with an attendance of about 10,000 over three hours

Energy-aware feedback control for production scheduling and capacity control

In this paper, we propose an energy-aware feedback control model for production scheduling and capacity control. Specifically, we integrate functions of production scheduling and capacity control, taking into account the costs of energy consumption and machine maintenance varied by production capacity, and the penalty cost imposed by just-in-time production requirements. Continuous control variables are used to adjust the system and the resulting dynamics are modelled. Computational experiments show that interrelated dynamics among these three performance factors are well explained by the proposed controllers, and considerably better energy performance, about 20.0-40.0% improvement, in an energy-aware production compared to a conventional strategy

Nonlinear dynamics in distributed arrival time control of heterarchical manufacturing systems

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Distributed system-level control of vehicles in a high-performance material transfer system

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