Design Of Shift Schedules Research Articles

An Adaptive Shift Schedule Design Method for Multi-Gear AMT Electric Vehicles Based on Dynamic Programming and Fuzzy Logical Control

This paper proposes an adaptive shift schedule design framework based on dynamic programming (DP) algorithm and fuzzy logical control to promote the shift schedule’s adaptability whilst improving the comprehensive performance of the multi-gear automated manual transmission (AMT) electric vehicles in real-time application. First, the DP algorithm is employed to extract an offline optimal gear-shift schedule based on a set of driving conditions, including 11 groups of typical driving cycles. Second, a fuzzy logical controller is formulated considering the variation in the vehicle load and acceleration, where a velocity increment is exported online to adjust the gear-shift velocity of the predesigned DP-based schedule to develop a Fuzzy-DP shift schedule. In addition, multi-objective particle swarm optimization (MOPSO) is utilized to construct a comprehensive shift schedule by simultaneously considering the dynamic and economic performance of the vehicle. Then, the dynamic and economic shift schedules are deployed as the benchmark to examine the performance of the proposed shift schedule. Finally, the effectiveness of the Fuzzy-DP shift schedule is evaluated by comparison with others under various combined driving cycles (including vehicle load and velocity). The comparisons demonstrate the remarkable promotion in the adaptability of the Fuzzy-DP shift schedule in terms of acceleration time, energy-saving potential, and shift frequency. The most significant improvements in the dynamic, economic, and shift frequency can reach 8.86%, 10.12%, and 8.56%, respectively, in contrast to the MOPSO-based shift schedule.

Staff Barriers to Fulfilling Assisted Living Resident Daily Care and Activity Preferences

Person-centered care (PCC), or delivery of care consistent with preferences, has been associated with improved care and quality of life for residents in long-term care (LTC). However, research has shown PCC has not been universally adopted. While general implementation barriers have been identified, little research has focused on barriers to meeting specific types of resident daily care and activity preferences. The purpose of this study was to describe LTC staff barriers to fulfilling specific types of resident preferences. A descriptive, qualitative study with 19 assisted living staff from nursing, dietary, and activities was conducted. Semi-structured interviews focused on identifying work system barriers to meeting specific types of resident preferences were analyzed using thematic analysis. Findings suggest shift assignments, staffing challenges, and facility schedules influence staff ability to meet certain types of preferences. The results suggest innovative design of shift schedules and assignments may help staff meet certain types of preferences. Part of a symposium sponsored by the Research in Quality of Care Interest Group.

Blending gear shift strategy design and comparison study for a battery electric city bus with AMT

To improve the performance of heuristic strategy used in most of the electric city buses equipped with automated manual transmission (AMT) currently, this paper proposes a systematic blending extraction method to optimize and accelerate the shift schedule design process. The crucial related factors, including the shift time, transmission efficiency and various driving cycle features, are considered to assure the online practicability. Dynamic programming (DP) algorithm is applied over featured velocity profiles to explore the global optimal operating points offline. Then k-means clustering algorithm is adopted to extract the explicit optimal shift schedule, where the number of centroids is determined by hierarchical analysis process and a new distance calculation method is performed considering proper weighting factors to blend the shift points from different driving conditions. The stochastical driving cycle is generated randomly from the previous data and is used to validate the comprehensive performance by chassis dynamometer tests. A comparison study is conducted among the proposed and conventional shift strategies. Experimental results demonstrate that the extracted blending strategy can improve the energy consumption significantly and is proved to be efficient, flexible, and online implementable compared to the other strategies.

Analysis of Optimal Shift Schedule Derivation for Electric City Buses Equipped with Automatic Manual Transmission

Since most of the electric city buses equipped with automated manual transmission (AMT) are currently implemented with a heuristic strategy, this paper proposes a systematic extraction method to optimize and accelerate the shift schedule design process. A dynamic model of the electric city bus with a four-speed AMT is established to study the energy management strategy. Dynamic programming (DP) algorithm is adopted to explore the offline global optimal control sequence considering the shift frequency. Then the feature of optimal operating points is analyzed and a time-saving derivation methodology is discussed to construct the gear shift schedule based on the clustering algorithm. The derived control strategy is proved to be efficient, flexible and online implementable. Simulation results show that the derived strategy can improve the energy economy by 4.45% compared with the preliminary empirical gear shift schedule, which is 57.8% better than back-propagation neural networks in a determined city route.

Optimal Gear Shift Schedule Design for Automated Vehicles: Hybrid System Based Analytical Approach

In this paper, we present a systematic design framework for gear shift schedule using hybrid system theory primarily intended for automated vehicles. The longitudinal motion of the vehicle is regulated by a PI controller that determines the required axle torque. The longitudinal dynamics of the vehicle with a gear box is modeled as a hybrid system, and an optimization-based gear shift schedule design is introduced. This guarantees that the propulsion requirements are delivered while minimizing fuel consumption. The resulting dynamics is proven to be stable in the presence of constraints. We apply our framework to heavy-duty vehicle gear shift schedule design and evaluate the performance of the controller using numerical simulations.

Mode Shift Control for a Hybrid Heavy-Duty Vehicle with Power-Split Transmission

Given that power-split transmission (PST) is considered to be a major powertrain technology for hybrid heavy-duty vehicles (HDVs), the development and application of PST in the HDVs make mode shift control an essential aspect of powertrain system design. This paper presents a shift schedule design and torque control strategy for a hybrid HDV with PST during mode shift, intended to reduce the output torque variation and improve the shift quality (SQ). Firstly, detailed dynamic models of the hybrid HDV are developed to analyze the mode shift characteristics. Then, a gear shift schedule calculation method including a dynamic shift schedule and an economic shift schedule is provided. Based on the dynamic models and the designed shift schedule, a mode shift performance simulator is built using MATLAB/Simulink, and simulations are carried out. Through analysis of the dynamic equations, it is seen that the inertia torques of the motor–generator lead to the occurrence of transition torque. To avoid the unwanted transition torque, we use a mode shift control strategy that coordinates the motor–generator torque to compensate for the transition torque. The simulation and experimental results demonstrate that the output torque variation during mode shift is effectively reduced by the proposed control strategy, thereby improving the SQ.

Comprehensive design and optimization of an electric vehicle powertrain equipped with a two-speed dual-clutch transmission

This article develops a systematic model to study electric vehicle powertrain system efficiency by combining a detailed model of two-speed dual-clutch transmission system efficiency losses with an electric vehicle powertrain system model. In this model, the design factors including selection of the electric machine, gear ratios’ change, multi-plate wet clutch design, and gear shift schedule design are considered. Meanwhile, the application of detailed model for drag torque losses in the gearbox is discussed. Furthermore, the proposed model, developed with the MATLAB/Simulink platform, is applied to optimize/maximize the efficiency of the electric vehicle powertrain system using genetic algorithms. The optimization results demonstrate that the optimal results are different between simulations via New Europe Drive Cycle and Urban Dynamometer Driving Schedule, and comprehensive design and optimization of the powertrain system are necessary.

Gear shift schedule design for multi-speed pure electric vehicles

As pure electric vehicles are considered to be a major growth trend in the automotive industry, research into and development of efficient electric powertrain systems and related control technologies have become popular research topics. The growing importance and use of multi-speed transmissions in these vehicles make shift schedule design and research a crucial aspect of the powertrain systems design of pure electric vehicles. This paper provides a gear shift schedule calculation method for pure electric vehicles, which includes a dynamic shift schedule and an economic shift schedule calculation method, demonstrating how to optimize the shift points and to produce the upshift and downshift lines based on the motor efficiency map. Through the establishment of a pure electric vehicle model, simulation results show that a properly designed shift schedule can improve the working region of the motor and can refine the dynamic performance and the economic performance of the vehicle. Finally, rig testing results are demonstrated to be comparable with simulations and indicate the correctness of the method.

BASS 4: a software system for ergonomic design and evaluation of working hours

To extend an existing computer programme for the evaluation and design of shift schedules (BASS 3) by integrating workload as well as economic aspects. The redesigned prototype BASS 4 includes a new module with a suitable and easily applicable screening method (EBA) for the assessment of the intensity of physical, emotional and cognitive workload components and their temporal patterns. Specified criterion functions based on these ratings allow for an adjustment of shift and rest duration according to the intensity of physical and mental workload. Furthermore, with regard to interactive effects both workload and temporal conditions, e.g. time of day, are taken into account. In a second new module, important economic aspects and criteria have been implemented. Different ergonomic solutions for scheduling problems can now also be evaluated with regard to their economic costs. The new version of the computer programme (BASS 4) can now simultaneously take into account numerous ergonomic, legal, agreed and economic criteria for the design and evaluation of working hours. BASS 4 can now be used as an instrument for the design and the evaluation of working hours with regard to legal, ergonomic and economic aspects at the shop floor as well as in administrative (e.g. health and safety inspection) and research problems.

Ergonomic criteria for the evaluation of shift schedules

Evaluation and design of working time arrangements gain importance due to economical changes and overall reduction of working time. Especially outside the industrial area, a variety of innovative arrangements of working time have been established. These processes underline the need for ergonomic criteria for the evaluation and design of shift schedules. There is general agreement that, due to varying side conditions, it is impossible to devise the one best shift schedule. Planning of shift schedules must reconcile diverse intentions and goals. Although the one best shift schedule does not exist, under the pre-condition of certain organizational, staff- and work-related features, different schedules could be ergonomically compared. A proposal is presented based on theoretical considerations following the lines of destabilization theory comprising of 10 comparative laws and 10 related principles for design and evaluation of working time arrangements. Because of varying and complex conditions found in the diverse economical sectors down to single plants and facilities, these principles must be complemented by a co-operative implementation strategy.

Participatory approaches to strategy and research in shift work intervention

Participation and alterations of shift schedules from a health and safety perspective are in focus. The paper elucidates the questions concerning what participatory approaches in particular have to give to the design of shift schedules and whether special conditions in shift schedule designing give participatory intervention approaches a special relevance. Reviewing intervention studies in shift work uncovers that a participatory approach is emphasized in several papers but only seldom descriptions of the participatory processes as pre-conditions, stages and dynamics are found. A specific participatory approach is appraised, and examples of general research operationalizations are provided, but it is underlined that it has to take place according to the organizational context of the intervention. In conclusion, it is assessed that shift work contains special issues like differences in attitudes and interests among the employees, negative adaptation, interplay between work time and social time that makes the potentials of participatory intervention research particularly applicable in changing shift schedules.

Human adaptation to shift work in improving health, safety and productivity – some recommendations

Advances in technology result in changes to working methods and patterns. These are compounded by the need to be competitive in a global economy. Particular changes are seen in many developing countries which are attempting to compete with the more sophisticated and advanced nations. Workers in such countries may find it difficult to adapt to the new working regimes. Currently, there is little information available in the literature that supports the effective design of shift schedules, which offer effective productivity levels, while maintaining the health and safety of shift workers and offering them appropriate levels of job satisfaction. Incorporates a multidimensional approach to addressing this issue and makes recommendations designed to improve the wellbeing of shift workers through a consideration of the effects of shift work on work attitudes, job satisfaction and family/social life, while recognising that any approach to change must be consistent with the local economic and competitive environment.

Computer-aided design of shift schedules

The complexities encountered in the design of shift schedules for continuous work, especially if such a design is to perform optimally against the criteria of organizational demands and ergonomics protocols simultaneously, inevitably demand computer support. This paper reports on the concept and development of a PC-based computer program for the design of shift schedules for continuous work with regular or irregular work demands. The results demonstrate that the program produces optimal solutions with respect to the criteria selected.

Effect of Shift Interval for The Clinical Nurse on the Circadian Rhythm

Circadian rhythm is entrained in the 24-hour time interval by periodic factors in the environment, known as zeitgeber. But most rotating work schedules are outside the range of the entrainment of the pacemaker timing the human circadian sleep-wake cycle. It has been postulated that physiological and emotional disturbances occur in most human functions when the circadian rhythm is disturbed. So application of circadian principles to the design of shift schedules can aid in maintaining the temporal integrity of the circadian system and thereby minimize for the shift worker any detrimental consequences of circadian disruption. This study was a quasi-experimental study to test the effect of shift intervals for the clinical nurse on the circadian rhythm. Twenty nurses newly employed in general units of two hospitals were selected as an experimental group and twelve college nursing students as a control group. Both groups were selected according to an established criteria using a purposive sampling technique. Ten subjects were assigned to a weekly shift group and another ten to a biweekly shift group engaged in a semi-continuous shift schedule (sunday off) with a backward direction; that is, morning-evening-night shift. The control group worked a morning shift for 42 days. Oral temperature rhythm, waking time, sleep-wake cycle, fatigue, and mental performance were measured during the experimental period. The data collection period was from April 30, 1990 to June 10, 1990. MANOVA, paired t-test, ANOVA, and Student Newman Keuls method were used for statistical analysis. The results are summarized as follows. 1. Phase delay in the acrophase of temperature rhythm was shown according to the backward rotating shift. A complete adaptation to work on the night shift was achieved between the sixth and ninth day of the night shift. 2. There was no difference in either waking time or sleep-wake cycle according to the duration of the working day for every shift group. Significant difference was found in the waking time and the sleep-wake cycle for subjects on the morning, evening, and night shift in both of the shift groups (weekly shift group: lambda = 0.121, p less than 0.01, lambda = 0.112, p less than 0.01, biweekly shift group: lambda = 0.116, p less than 0.01, lambda = 0.084, p less than 0.01). 3. There was no difference in fatigue between the first working day and the last working day for the control group and for the biweekly shift group.(ABSTRACT TRUNCATED AT 400 WORDS)

Forward versus Backward Shift Rotation

The U.S. Bureau of Mines has been involved in the study of guidelines for the design of shiftwork schedules. One popular suggestion offered by shiftwork researchers and consultants is to establish schedules that rotate in a forward direction (Day to Afternoon to Nights) rather than backward (Day to Night to Afternoon). This paper analyzes the two primary premises behind these suggestions. Data on subjective sleep times collected from both forward and backward rotators, indicate that the Forward rotation may not be more beneficial than the Backward rotation. Although the WORK start times of a forward schedule parallels the direction for faster biological adjustment, SLEEP times do not. Also, the between-shift intervals for forward direction shifts are not necessarily more conducive for more flexible shift schedule design given the sleep behaviors of shiftworkers.

Features of Circadian Rhythms Relevant for the Design of Shift Schedules

The first part of this paper reviews properties of circadian rhythms when free-running in constant conditions, or in situations where zeitgebers are insufficient for entrainment. The second part de...