Performance Analysis of Ergonomics-based Manual Assembly Line with Parallel Workstations and Floaters
It has been long known that manual assembly tasks are repetitive and require the use of specific muscles in the upper extremities, creating excessive postural and physical loads on the excessively used body members. As a result, manual assembly line workers are at high risk of cumulative trauma disorders in the upper extremities. When ergonomics concerns are introduced to the manual assembly line balancing problem to assign assembly tasks to workers to achieve the maximum postural-physical loads smoothness, the resulting task-workstation assignment solution must be determined using an ergonomics-based approach. Unfortunately, the line throughput is likely to decrease since the balance delay of the line might be compromised. This research project is intended to investigate the effect of adding parallel workstations to some potential bottleneck workstations and providing floaters (or extra helpers) to those parallel workstations so as to increase the assembly line productivity. Additionally, several strategies for opening parallel workstations and rotating floaters among them will be investigated with respect to various desired throughput rates. The Rapid Upper Limb Assessment (RULA) technique will be used to assess the postural and physical loads imposing on the musculoskeletal system of the body when performing each manual assembly task. A heuristic procedure will be employed to assign assembly tasks to workstations using a mixed productivity and ergonomics consideration. Based on predefined dispatching strategies to assign floaters and rotate them among parallel workstations, simulation models will be developed. The performance of the given manual assembly line under different throughput rate requirements and operational conditions will be analyzed. The variables of interest include: throughput rate, number of full-time workstations, number of parallel workstations, number of floaters, dispatching strategy, and switchover strategy. The performance indices are: achieved throughput rate, balance delay, utilization rates of full-time and parallel workstations, switchover rates, and average queue lengths at full-time workstations.
Ergonomics-based Workforce Scheduling for the Vehicle Routing Problem
The vehicle routing problem is intended to determine the optimal number of vehicles to delivery goods between finite sets of origins and destinations, and their delivery routes. There are numerous variants of the vehicle scheduling problem that have been studied by operations research and industrial engineering researchers. However, very few (if any) have paid attention to the vehicle drivers. In real-world situations, vehicle drivers might not only drive delivery vehicles but also perform loading and unloading of goods at both the origins and destinations. With limited time windows, loading/unloading operations may require more than one person to perform. Moreover, long-distance driving is stressful and increases the risk of highway accidents. Alternate drivers may be required for certain delivery routes. This research project is intended to take the loading/unloading workload and long-distance driving into consideration when finding the optimal workforce schedule for the vehicle routing problem. Based on the given delivery loads (in terms of required energy costs) and the driving distances for individual delivery trucks, a heuristic approach will be developed to determine the minimum numbers of vehicles and operators (drivers and movers) and their delivery routes so as to minimize the total traveling distance without exceeding the recommended daily energy expenditure and driving distance.
Workforce Scheduler: An Ergonomic Manpower Management Tool
This research project is intended to develop a computerized tool called Workforce Scheduler for ergonomically managing manpower for the hazardous work system. A group of industrial workers will receive daily work assignments to operate/attend a set of machines/workstations in the workplace where ergonomics, safety, and health hazards are present. Job rotation will be implemented to alleviate the workers’ hazard exposures. The types of hazard considered in Workforce Scheduler include industrial noise, heat, over-exhaustion, over-exertion, and toxic gases. Workers may be considered as identical or non-identical receivers, depending on the type of hazard and body tolerance. Workforce Scheduler allows the user to choose between the single-hazard exposure option and the two-hazard exposure option. The permissible daily exposure level must be specified prior to the workforce scheduling. Workforce Scheduler will determine the daily work assignment for each worker such that his/her hazard exposure does not exceed the permissible level. Additionally, weekly work schedule for the worker can be set so that his/her daily hazard exposures for different workdays will not be the same.
|Master Thesis Supervised|
|2007 :||Sakib Jalil. Decision Support System for Workstation and Notebook Computer Settings for Ergonomic Work Posture.
|Doctoral Theses Supervised|
|2003 :||Tarathorn Kullpattaranirun. A Genetic Algorithm Approach to Safety-based Work Assignment Problems.|
|2004 :||Busagarin Rurkhamet. An Expert System for Recommending Ergonomics and Quantitative VDT Workstation Settings and Computer Accessories Layout.|
|2005 :||Chorkaew Jaturanonda. Analytic and Decision Support System Approaches to Employee-Job Assignment Problem based on Person-Job Fit.|
|2006 :||Sorawit Yaoyuenyong. Algorithms for the Safety-based Workforce Scheduling Problem.|
|2006:||Krisada Asawarungsaengkul. Analytical Design of Effective Industrial Noise Hazard Prevention Strategy and Auditory Warning System for Adequate Audibility.|