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Cognitive assistance systems help people with learning disabilities to increase their skills and consequently their employment opportunities in the regular labour market. Research on advanced work instructions has encouraged training disabled workers in cognitively demanding production tasks, especially manual assembly. However, studies lack evidence on the effect of repetition or work cycle alongside the form of instruction and type of disability. This paper addresses this gap and reports on an experiment conducted at a sheltered workplace. Four forms of instruction (paper-based, animations, projection, adaptive projection) were tested to assist operators with three types of disability (illiterate, psychosocial, cognitive) with a manual assembly task. The results show that projection enhances the first assembly cycle. Challenging operators by filtering the content of the instruction with increased experience leads to greater independence and a better understanding of their tasks. However, adaptive instructions can form a barrier for those operators who are most dependent on mentor support. The form of instruction should thus be considered carefully for each operator as their adaptation to changes and cognitive assistance systems varies. The results are discussed in light of the Industry 5.0 human-centric and socially sustainable production agenda with managerial and research implications and future research priorities. [ABSTRACT FROM AUTHOR]

In variable manual assembly production of highly customised products, effective allocation of workers to products is required. To support decision-making here, industrial managers should be aware of the performance effects of the number of workers and learning within individual products. Evidence on such fundamental effects requires laboratory studies with products similar to those in real assembly industries. Because of the lack of such studies, this paper studies experimentally the effects of group size (one to four workers) and learning (up to four repetitions per group) on the performance of product assembly. The product, built for the purpose of the present study, consists of representative elements from real products in the mechanical engineering industry. A total of 68 undergraduate students participated in the experiments. The results from the experiments are in line with the hypotheses that the mean assembly time decreases at a decelerating rate as a function of both group size and repetitions, and that productivity per worker decreases as a function of group size. The results are explained in more detail through the experiences of the participants. Managerial implications and aspects for future research are also discussed. [ABSTRACT FROM AUTHOR]

Varying workloads and uncertain processing times in parallel assembly cause idle times for skilled, high-cost workers. This idleness can be avoided and the utilisation of the workers improved by allowing workers to move between the stations to help each other. Worker movement between assembly stations needs efficient and feasible coordination, and therefore, this paper compares four different worker coordination policies: no helping, floater, pairs and complete helping. The dynamics of the policies are modelled by studying the parallel assembly as a continuous-time Markov process. The system is studied with two different job release cases for non-identical jobs (customised products). In the first case, a given number of jobs have to be completed by the entire system. In the second case, new jobs arrive with a Poisson-distributed rate. The models assume that when one worker helps another, their collaborative inefficiency reduces the productivity. The models are used in numerical experiments to compare the performances of worker coordination policies as average job cycle times. The main conclusions from the results suggest the use of the complete helping policy in minor collaborative inefficiency conditions, especially with a given set of jobs. The pairs policy is a reasonable alternative in major inefficiency conditions with the continuous arrival of jobs. [ABSTRACT FROM PUBLISHER]