Chairless Chair Exoskeleton. Work-physiological-biomechanical Analysis of the Lower Extremities

Chairless Chair Exoskeleton. Work-physiological-biomechanical Analysis of the Lower Extremities

Standing work is associated with increased risks of venous and musculoskeletal disorders; particularly low back pain is commonly reported in prolonged standing work. In manufacturing work, workstations often do not allow standing aids due to insufficient functional and spatial conditions. In 2014, the car manufacturer Audi introduced the lower leg exoskeleton developed by Noonee to their employees working in the factories. This exoskeleton, the 'Chairless Chair' has the advantage that standing work can be performed while technically sitting on this device. The exoskeleton offers the potential for reduced awkward body postures, but it is unclear which physiological and biomechanical loads are influenced and how. This proposal provides a study design evaluating the 'Chairless Chair' in a laboratory setting, by testing its effectiveness in terms of physiological and biomechanical parameters. It is suggested to compare different assembly tasks while wearing the exoskeleton, compared with not wearing the exoskeleton. The 'Chairless Chair' is developed in one size only, which is why we propose to include participants of different body height, which will enable us to investigate whether body height influences the effectiveness of wearing the device.

Each participant was exposed to all experimental conditions, which were the following:

• Standing without the exoskeleton
• Sitting with the exoskeleton

For both experimental conditions, the working height was adjusted to the individual to become optimal. The working distance to the simulated assembly tasks was also adjusted to the individual to become optimal. Both the working height and distance were based on textual guidelines provided in DIN EN ISO 14738:2009-07.

Each work cycle consisted of assembling and disassembling the following three tasks:

• Screwing
• Clip fitting
• Cable mounting

In addition, we investigated suboptimal working heights and distances. The results of these suboptimal conditions will not be reported in the results on this website, but in a separate publication.

Inclusion Criteria:

• Age: between 18 and 40 years old;
• Gender: male;
• Voluntary informed consent (oral and written) is obligatory for study participation.

Exclusion Criteria:

• Age: <18 and >40 years old;
• Gender: female;
• People under the influence of intoxicants, analgesics, or muscle relaxants;
• Alcohol abuse;
• People with cardiovascular diseases;
• People with a heart pacemaker;
• People with a disability who, due to their restriction at a workplace of this kind, will not be able to participate;
• People with Diabetes Mellitus;
• People with severe muscle contractions of the lower extremities, back or arms;
• People with acute ailments or pain;
• People who are unable to complete the examination program due to language or cognitive obstacles;
• Depending on the degree of severity, people with diseases of the veins and joints of the lower extremities, spine, muscle disorders, symptomatic neurological-psychiatric diseases, acute pain syndromes, maladies or other current diseases.