U-line assembly systems - instruments for risk assessment and ergonomic design recommendations for prevention

Below you will find a short summary of the project. For further information please contact the project managers via the contact button on the right side.


U-line assembly systems are workstations which are arranged in the form of a U according to the one-piece flow concept. These are hybrid systems in which automated processes are supplemented by manual activities. Depending on the job situation, one or more employees are flexibly deployed in U-lines. Intensive manual work in U-lines can lead to musculoskeletal disorders of the upper extremities and shoulder belt. This depends essentially on the work design. In U-lines, these include short movement cycles with highly dynamic and fine-motor finger-hand and arm movements, for example. U-lines can also cause increased strain on the lower extremities. Due to the circularity of the working persons in U-line assembly systems, lateral steps and rotational movements in the lower back area can occur, representing a significantly different stress pattern compared to “conventional" walking.


The research project had typified U-shaped assembly line of varying complexity and examine interactions of physical and mental workloads using a holistic methodological approach.


  • A balanced and holistic approach for analysis of physical and mental stress and physiological strain in U-shaped assembly lines.
  • research methods and tools for analysis of physical and mental stress and physiological strain in U-shaped lines.
  • Results concerning physical workloads on upper and low extremities while working in different types of U-shaped assembly lines
  • Technical and organizational ergonomic measurements regarding U-shaped assembly lines taking into account physical fatigue, monotony and mental saturation as well as physiological strain.
  • Processing of the results for the specification of the main study on human-compatible work design of chaku-chaku work systems.

Wakula, J.; Bauer, S. ; Spindler, S. ; Bruder, R. (2017): Analyse von Belastungen und muskulären Beanspruchungen der unteren Extremitäten beim „seitlichen“ Gehen an einer simulierten Montagelinie mit unterschiedlichen Laufrichtungen und kurzen Taktzeiten.
In: 63. Kongress der Gesellschaft für Arbeitswissenschaft, 15.02-17.02.2017, Brugg (Schweiz).

Wakula, Jurij ; Müglich, Dorothee ; Bruder, Ralph :
„Normales“ vs. „seitliches Gehen“ bei simulierten einfachen Montagetätigkeiten – Analyse der muskulären Beanspruchungen in den Beinen.
In: 62. Frühjahrskongress der Gesellschaft für Arbeitswissenschaft, 02.-04.03.2016, Aachen

Wakula, Jurij ; Fichtner, Konstantin ; Bruder, Ralph:
Analyse der physischen Belastungen und muskuläre Beanspruchungen an der simulierten U-Montagelinie mit unterschiedlichen Mechanisierungsgrad in der Prozesslernfabrik der TU Darmstadt.
In: 62. Frühjahrskongress der Gesellschaft für Arbeitswissenschaft, 02.- 04.03.2016, Aachen