Sampling and analysis or visual examination of soil to assess its status and use potential is widely practiced from plot to national scales. However, the choice of relevant soil attributes and ...interpretation of measurements are not straightforward, because of the complexity and site-specificity of soils, legacy effects of previous land use, and trade-offs between ecosystem services. Here we review soil quality and related concepts, in terms of definition, assessment approaches, and indicator selection and interpretation. We identify the most frequently used soil quality indicators under agricultural land use. We find that explicit evaluation of soil quality with respect to specific soil threats, soil functions and ecosystem services has rarely been implemented, and few approaches provide clear interpretation schemes of measured indicator values. This limits their adoption by land managers as well as policy. We also consider novel indicators that address currently neglected though important soil properties and processes, and we list the crucial steps in the development of a soil quality assessment procedure that is scientifically sound and supports management and policy decisions that account for the multi-functionality of soil. This requires the involvement of the pertinent actors, stakeholders and end-users to a much larger degree than practiced to date.
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•We review soil quality and related concepts in terms of definitions and assessment.•The most common indicators are organic matter, pH, available P and water storage.•Biological/biochemical indicators are under-represented but show great potential.•Soil quality assessment should specify targeted soil threats, functions and ecosystem services.•Increasingly interactive assessment tools must be developed with target users.
The paper presents an algorithm for integrated scheduling, dispatching, and conflict-free routing of jobs and AGVs in FMS environment using a hybrid genetic algorithm. The algorithm generates an ...integrated schedule and detail routing paths while optimizing makespan, AGV travel time, and penalty cost due to jobs tardiness and delay as a result of conflict avoidance. The multi-objective fitness function use adaptive weight approach to assign weights to each objective for every generation based on objective improvement performance. Fuzzy expert system is used to control genetic operators using the overall population performance improvements of the last two previous generations. Computational experiments was conducted on the developed algorithm coded in Matlab to test the effectiveness of the algorithm. Integrated scheduling of jobs in FMS which are in synchrony with AGV dispatching, scheduling, and routing proved to ensure the feasibility and effectiveness of all the solutions of the integrated constituent elements.
•The dispatch and conflict-free routing problem for capacitated AGV systems (DCFRPC) is proposed.•An integer program of the DCFRPC are presented.•Random and local search methods are proposed.•The ...methods are empirically evaluated though computational experiments.
Automated guided vehicles (AGVs) are an unmanned transport system used for the horizontal movement of materials. The dispatching and routing problem (DRP) for AGV systems involves making dispatching and routing decisions. The DRP is an important and fundamental problem in the scheduling of AGV systems, and number of studies have been conducted. However, for the application to real AGV systems, we have to consider additional constraints such as collision avoidance, the capacity of the system components, the ease of changing routes, and robustness against disturbance. This paper studies the dispatch and conflict-free routing problem of capacitated AGV systems (DCFRPC). In the DCFRPC, finite capacity for each vehicle and machine buffer is imposed, and task dispatching and conflict-free routing must be achieved. This paper formulates the DCFRPC as an integer program, and then, local/random search methods are proposed. This paper also empirically evaluates the proposed methods through computational experiments.
The European Innovation Partnership Agri has set up a consultation process involving 20 experts from 11 EU countries to discuss the potential of a substantial increase in protein crop production in ...the EU. The dependency of Europe on soya bean meal imports and the associated drivers are described and underline the need for change. The EIP Agri process resulted in the assessment of the present-day yield gap of protein crops using an approach based on the market values of the protein, starch and plant oil components. Oil-based protein crops seemed to be overall better positioned than starch based protein crops because the price of oil levels is higher than that of starch. Alfalfa was identified as being interesting for regions where drying cost are low. The process also resulted in the identification of opportunities and constraints to be encountered by the innovation process, combining the knowledge and physical infrastructure, market structure, co-operation and interaction and the influence of culturally determined values and beliefs. Therefore, the recommendation is to develop a comprehensive approach to meet the challenge of substantially increasing the EU’s protein crop production
This paper studies tracking control problem which is applied on the 16-wheel heavy-duty AGV(Automated Guided Vehicle). Firstly, the trajectory detection scheme is designed based on magnetic ...navigation sensors. Secondly, the 16-wheel heavy-duty AGV control model is simplified as a two-wheel AGV model according to Ackermann steering principle, and fuzzy trajectory control regulation is established based on car driving experience. Finally, a trajectory control simulation system for circular/straight trajectories is built in MATLAB Simulink to verify the effectiveness on trajectory control.
Abstract
Due to the influence of full traversal environment, the path length obtained by existing methods is too long. In order to improve the performance of path planning and obtain the optimal ...path, a full traversal path planning method for omnidirectional mobile robots based on ant colony algorithm is proposed. On the basis of the topology modeling schematic diagram, according to the position information of the mobile robot in the original coordinate system, a new environment model is established by using the Angle transformation. Considering the existing problems of ant colony algorithm, the decline coefficient is introduced into the heuristic function to update the local pheromone, and the volatility coefficient of the pheromone is adjusted by setting the iteration threshold. Finally, through the design of path planning process, the planning of omnidirectional mobile robot’s full traversal path is realized. Experimental results show that the proposed method can not only shorten the full traversal path length, but also shorten the time of path planning to obtain the optimal path, thus improving the performance of full traversal path planning of omnidirectional mobile robot.
Automated Guided Vehicles (AGVs) are self-driving vehicles used for transporting goods and materials throughout different areas, such as shipping and receiving areas, storage facilities, and ...workstations. The popularity of AGVs has grown rapidly due to their many benefits, including flexibility in processes, efficient use of space, product safety, and computer integration and control. The design and management of AGV-based systems present various tactical decisions, such as fleet sizing and flow path design, as well as operational decisions such as dispatching, routing, and scheduling.
In this study, we focus on a scheduling problem faced by a manufacturing company that utilizes AGVs subject to battery constraints for the horizontal movement of materials. Unlike previous studies, we investigate a Multi-objective AGV scheduling problem where both the AGV fleet size and the makespan need to be minimized. Additionally, AGV charging time depends on battery depletion. To support the company decision-making system, we propose a Mixed Integer Linear Programming formulation and a genetic algorithm. We have tested and validated our proposed methods using real-world instances provided by a manufacturing company. The results show the efficacy and the scalability of the proposed solution methods.
Energy Optimization of Large-Scale AGV Systems Riazi, Sarmad; Bengtsson, Kristofer; Lennartson, Bengt
IEEE transactions on automation science and engineering,
04/2021, Letnik:
18, Številka:
2
Journal Article
We propose an efficient optimization method, which addresses several performance criteria, such as makespan, maximum lateness, and the sum of tardiness for an automated guided vehicle (AGV) system, ...together with its energy consumption. We show that the most important factors in energy consumption of AGVs are their cruise velocities and traveled distances. We also demonstrate that optimizing the productivity-related performance criteria also reduces energy consumption through less traveled distance. It also allows for the reduction of the cruise velocity, which leads to more energy savings. Our experiments demonstrate that the optimization method outperforms the existing traffic controller with respect to the performance criteria and reduces energy consumption. The proposed method can reduce the energy consumption by around 38%, while the values of makespan, lateness, and tardiness remain better than those obtained from the existing traffic controller. An important advantage of this article is that the evaluations are based on collected data from a real large-scale manufacturing plant. Note to Practitioners -It is commonly believed that reduction of speed, for example, due to safety reasons in critical areas, in automated guided vehicle (AGV) systems leads to lower system efficiency. However, it has been shown that speed management is an effective strategy to reduce the energy consumption of mobile robots and robot stations. If one seeks to utilize the existing slacks in the schedule of the AGVs, it should be possible to reduce energy consumption without affecting system efficiency. It can, furthermore, be combined with better scheduling to even improve performance measures, such as makespan, while reducing energy. In this article, we propose an optimization method that seeks to minimize the number of performance measures, such as makespan, maximum lateness, and sum of tardiness for a real AGV system designed by AGVE, which operates at Volvo Cars, Gothenburg, Sweden. We also show that the optimization method allows for reduction of cruise speed, while the mentioned performance measures are still better than the one obtained from the original traffic controller. We will also show the importance of taking into account the temperature of the drive system of the AGVs when performing energy measurements.
•In the commercially available offer, current systems almost all work fully centralized lacking flexibility, robustness, and scalability. But a trend towards a decentralized control is emerging.•The ...abundance of literature shows us that many algorithms already exist for the control of AGV systems in lab environments, both central and decentral.•The industry 4.0 paradigm will push AGV manufacturers to think about decentralization as systems will become even larger and complex.•More decentralized and market-based techniques are suited to introduce flexibility and scalability in the system.•The control of an AGV system can be decomposed into five core tasks which are task allocation, navigation, path planning, motion planning and vehicle management.
Automated guided vehicles (AGVs) form a large and important part of the logistic transport systems in today's industry. They are used on a large scale, especially in Europe, for over a decade. Current employed AGV systems and current systems offered by global manufacturers almost all operate under a form of centralized control: one central controller controls the whole fleet of AGVs. The authors do see a trend towards decentralized systems where AGVs make individual decisions favoring flexibility, robustness, and scalability of transportation. Promoted by the paradigm shift of Industry 4.0 and future requirements, more research is conducted towards the decentralization of AGV-systems in academia while global leading manufacturers start to take an active interest. That said, this implementation seems still in infancy. Currently, literature is dominated by central as well as by decentral control techniques and algorithms. For researchers in the field and for AGV developers, it is hard to find structure in the growing amount of algorithms for various types of applications. This paper is, to this purpose, meant to provide a good overview of all AGV-related control algorithms and techniques. Not only those that were used in the early stages of AGVs, but also the algorithms and techniques used in the most recent AGV-systems, as well as the algorithms and techniques with high potential.
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