A 3D analysis of the joint torques developed during driver's ingress–egress motion

Abstract

Providing an easy ingress–egress (I/E) movement remains a challenge for car designers. I/E has been largely studied in kinematics, but not in dynamics. This study proposes: (1) to evaluate and describe the motor torques developed in the lower limbs and lumbar joints during I/E motions and (2) to analyse the influence of the car geometry and subject anthropometry. An experiment was performed to observe 15 subjects of three anthropometrical groups getting in and out of a car mock-up simulating three different vehicle configurations. Motor torques were extracted using an inverse dynamics analysis. Both ingress and egress motions were primarily characterised by large torques. Overall, the taller a subject and the lower the seat of the vehicle were, the larger the peak torques were. Moreover, peak torques were higher for egress than ingress. These results are discussed in regard to the current knowledge on I/E ergonomics.

Abstract

Practitioner Summary: Car ingress–egress (I/E) is an ergonomics challenge. Little is known about the physical efforts developed in this motion. Developed motor torques were experimentally assessed for three anthropometrical groups and vehicle configurations. Results obtained were discussed in regard to the current knowledge on I/E ergonomics.

Keywords::

• ingress–egress
• joint torques
• 3D human motion analysis
• biomechanics
• digital human model

Acknowledgements

Preliminary results of this work were presented in the following conferences: International Digital Human Modeling Symposium, 11–13 June 2013, Ann Arbor (USA) and International Symposium on the 3D Analysis of Human Movement, 18–20 July, Bologna (Italy).