摘要:

This paper describes the development of an intelligent controller for a fleet of free-ranging automated guided vehicles. The vehicle controller will operate in real-time. Once a transportation request is received, the location where the demand is generated and the nature of the demand is sent to the vehicle controller. Based on this information and the current status of the system, the vehicle controller will perform dispatching, routing, and scheduling tasks for the free-ranging vehicles. For the selected vehicle, the vehicle controller finds a route and then it will schedule the vehicle along that route in a non-conflicting manner. The vehicle controller is capable of detecting and preventing collisions before they occur. Once a collision is detected, the vehicle controller will explore different solutions to prevent the collision. The alternative which will result in the least delay time is the solution which will be selected by the vehicle controller. The inputs to the system are the layout topology, the number of vehicles in the system, and the vehicles' characteristics.

ISSN:0020-7543    

DOI:10.1080/00207548808947852

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper deals with an order picking problem in an automated storage and retrieval system (AS/RS). We present heuristic algorithms for batching a set of orders such that the total distance travelled by the order picking machine is minimized. These algorithms are based on cluster analysis and their efficiency and validity are illustrated through computer simulation. The results show that the algorithms developed perform substantially better than those from previous studies.

ISSN:0020-7543    

DOI:10.1080/00207548808947853

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In a complete inspection plan, all outgoing items are subject to inspection, and the items failing to conform to the predetermined specifications are reworked so that their quality characteristics are exactly equal to the expected value (target value). This paper presents an economic model to determine the most profitable specifications for the complete inspection plan with the considerations of (a) economic loss caused by quality deviations, (b) rework cost, and (c) inspection cost. The solution to the cases in which the inspection cost is a constant provides important insights of the model. A detailed solution procedure is also given to a model in which the inspection cost is a linear function of the width of the specifications, the quality characteristic is normally distributed, and other loss and cost functions are assumed of a quadratic or linear form.

ISSN:0020-7543    

DOI:10.1080/00207548808947854

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This research utilized a biomechanical approach for the investigation of body weight effects in a manual-lifting activity. Following a 3-day training session, 10 male subjects performed 6 tasks in 12 trials. For each trial, the subject was directed to use a free style posture to lift a weighted box from the floor to a 0.762m high shelf. In order to evaluate the forces and torques generated by the external load and the body weight acting on the articulations and vertebra during the lifting task, the experimenter used a high-speed camera to record the lifting activity, a GP-8 Sonic Digitizer to translate the motion into coordinates, and a biomechanical program to calculate the forces acting on the L5/S1 disc, the maximum abdominal force,and the torque acting on the abdomen. After the statistical analysis, two regression models were developed, which provide a convenient and useful means to quantify the maximum compressive and shear forces acting on the low back area during a sagittal plane-lifting activity. The model for the maximum compressive force acting on the L5/S1 disc in kilograms accounted for 95% of the variability in observed data (R2= 0.9506); the model for the maximum shear force acting on the same disc in kilograms accounted for 93% of the variability in observed data (R2= 0.9269).

ISSN:0020-7543    

DOI:10.1080/00207548808947855

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A discussion on the multi-dimensional character of flexibility is presented and an approach is suggested to define and measure flexibility. Petri nets are used as a design representation of an FMS for the purpose of comparing different systems on a flexibility basis thus unveiling their desirable flexibility properties.

ISSN:0020-7543    

DOI:10.1080/00207548808947856

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Dynamic lot sizing heuristics commonly implemented in standard MRP software perform well under conditions of systematic demand only. A survey and numerical test of methods proposed in the literature shows that techniques are available which cope efficiently with both systematic and erratic demand. The paper discusses theoretical and practical ramifications of the dynamic lot sizing problem, surveys heuristics published in the U.S. and West German literature, reports summarily on the findings of extensive simulation experiments involving these heuristics, and, as a conclusion from analytical and numerical results, proposes an algorithm which enhances performance under conditions of erratic demand.

ISSN:0020-7543    

DOI:10.1080/00207548808947857

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In an assembly system with a fixed number of workers, job enlargement leads to parallel lines. Job enlargement reduces absenteeism and turnovers, thereby increasing productivity. Job enlargement also reduces the number of repetitions per period reducing the learning effect and hence productivity. In an optimal job design, the loss of learning must be traded off with the reduction in absenteeism and turnovers. In this paper we show that an optimal job design exists with respect to the system response time and propose an analytical model to achieve such a design. Our experience with the model suggests that an optimal job design is most important when a new system is considered, and when significant learning takes place.

ISSN:0020-7543    

DOI:10.1080/00207548808947858

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A mathematical model, incorporating a matrix-tree-chain method for generating a tolerance chart and the method of tracing has been established based on the tolerance chart technique. A mathematical method for performing calculations of working dimensions and specification of tolerances in manufacturing processes is proposed. An interactive computer aided dimensional planning system CADP is presented.

ISSN:0020-7543    

DOI:10.1080/00207548808947859

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper solves the problem of calculating the efficiency ofMgroups ofNmachines under the care of one operative (robot), whose way of working is to patrol the groups either uni-directionally or bi-directionally, depending on whether they are located on a circle or on a line. Each group of machines is situated on a rotating circular disc (carousel). This work extends the work of Kim and Koenigsberg (1987) as well as the earlier work of Koenigsberg and Mamer (1982) and uses both of the models derived by Bunday and El-Badri (1984) and Bundayet al.(1985) for the uni-directional and the bi-directional patrolling problems. The problem arises in the practical context of a textile winding process and has some other industrial applications. Results are of value in maintaining controls and monitoring the process. A comparison of the two models considered in this paper can be made both numerically and graphically and, as has been shown before by Bunday and El-Badri (1985a, b), higher results for the efficiency, are obtained by patrolling uni-directionally rather than patrolling bi-directionally.

ISSN:0020-7543    

DOI:10.1080/00207548808947860

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The existing models for machine requirements planning are based on the assumption of a constant production rate per machine throughout the planning horizon. This assumption is not valid in many production environments where the manufacturing productivity increases because of factors like: product and process redesign, more efficient maintenance and setup procedures, direct-labour learning, reduction of scrap losses, etc. The objective of this paper is to present the effects of improving manufacturing productivity on machine requirements planning, In addition, an integrated model which combines the aggregate production planning and machine requirements planning problems is discussed under the effects of manufacturing progress function.

ISSN:0020-7543    

DOI:10.1080/00207548808947861

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor