Multi-objective ergonomic–economic project scheduling in construction: The case of photovoltaic system installation

The prevalence of work-related musculoskeletal disorders (WMSD) poses a significant challenge for construction companies. These disorders cause severe physical distress for affected workers, as well as reduced productivity, increased absenteeism, and escalating healthcare costs. The situation is exacerbated by ongoing labour shortages and shifting workforce demographics. To address this issue, we present a novel multi-objective decision support framework designed to optimise construction projects both ergonomically and economically. The proposed Bi-MRCPSP expands upon the multi-mode resource-constrained project scheduling problem (MRCPSP) by additionally incorporating worker equipment modes. We consider three objectives: (1) project duration, (2) resource availability cost, and (3) workers’ energy expenditure. Within this framework, three ergonomic interventions are integrated: (1) additional workforce, (2) planned recovery breaks, and (3) the use of exoskeletons. Applying the model to the installation of photovoltaic (PV) systems in residential homes demonstrates its validity and ability to support decision-making for the selection and implementation of interventions. A key finding is that exoskeletons enable more time- and cost-efficient ergonomic workplace designs, encouraging both companies and researchers to explore this technology further.