This dissertation investigates the critical role of hand coupling in human interaction with objects, focusing on the biomechanical forces involved in gripping and manipulating cylindrical handles. The research addresses the fundamental problem of slippage, which can lead to task failure and hand injuries, as well as the cumulative effects of forceful exertions such as fatigue and musculoskeletal disorders. By developing and evaluating biomechanical models, the study examines the interplay between axial torque and push forces, contact force distribution, friction, handle size, and force application direction. The work also proposes a practical field method for measuring hand static friction coefficients, aiming to inform the design of safer and more efficient work objects.

The research presented in this dissertation offers a detailed biomechanical analysis of hand coupling, with a particular emphasis on the forces and friction involved in gripping cylindrical handles. The development of practical models and measurement techniques aims to provide ergonomics practitioners and product designers with tools to create safer and more efficient work objects. The findings are intended to directly inform design processes, with the goal of reducing the incidence of hand slippage, muscle fatigue, and musculoskeletal disorders associated with manual tasks.