EMMA4Drive – Dynamic Human Model for More Safety and Comfort in Autonomous Vehicles

For many employees, it's an inviting vision of the future: driving to work in their own car and still making good use of their travel time – reading the news, checking e-mails or relaxing and enjoying the first coffee of the day.

In order to understand the expectations of customers of autonomous vehicles, to strengthen their trust and to prove safety, new digital tools are needed for research, development and validation of the technology. With the EMMA4Drive project, our researchers are further developing the dynamic human model EMMA for use in fully or partially autonomous driving vehicles.

Motion Sequences Instead of Quasi-Static Tests

So far, human models have mostly been used in crash simulations to estimate the risk of injury or in ergonomics analyses. However, detailed, computationally time-intensive models for calculations in the millisecond range are used here, which are not suitable for the simulation of dynamic driving maneuvers, since longer processes have to be simulated here. Another field of application for digital human models are ergonomics analyses in assembly planning. The models used for this purpose often only represent postures of the human body or quasi-static motion sequences by means of highly simplified multi-body kinematics. Such models do not take dynamic effects into account and the analysis of physical loads is hardly possible, since pure kinematics models can provide little information about biomechanics.

IPS IMMA digital human model in a relaxed position — © Fraunhofer ITWM
The digital human model IPS IMMA takes a short break in the vehicle. EMMA helps to answer the question of how to assess comfort under dynamic driving manoeuvres even in such relaxed postures.

Sit Better, Operate More Comfortably

»Our human model, on the other hand, uses an optimization algorithm to automatically calculate new body postures and entire motion sequences over a longer time window with the associated muscle activities«, explains project manager Dr. Marius Obentheuer. »This means that the simulation model can also be used to investigate the effect of dynamic driving maneuvers on humans and their (reaction) behavior – for example, in the design of assistance systems or control algorithms for (partially) autonomous driving.« EMMA4Drive thus enables comparatively simple implementation of new movement patterns and efficient virtual investigation of safety, comfort and ergonomics in (partially) autonomous driving.

Predecessor Project EMMA-CC

Modeling and efficient simulation of human motion for applications in ergonomics (work planning, virtual training, etc. in various industries), medicine and computer graphics are major challenges. The EMMA4Drive project is based on developments of the EMMA-CC project.

EMMA-CC stands for »Ergo-dynamic Moving Manikin with Cognitve Control« and is an old acquaintance: In the MAVO project of the same name, six Fraunhofer institutes had collaborated on digital human modeling for the simulation-based ergonomic design of workplaces in order to use it to set up safe and healthy workplaces in product development and production planning in the future.

The further development EMMA4Drive now virtually takes a seat in the car and dynamically simulates the interaction of human body parts and the vehicle seat during driving maneuvers. As a digital image of the occupants, the resulting software prototype will help analyze and evaluate new seating concepts in the passenger compartment in terms of safety and ergonomics during driving maneuvers.

EMMA bone model on a car seat — © Uni Stuttgart
The EMMA bone model is based on established occupant simulation models – this means that the motion data obtained can be further processed in other models, for example in crash simulations.

© Fraunhofer ITWM
A digital image of a female driver is used to model quasi-static sitting in the vehicle seat.

EMMA on RODOS

And before EMMA is allowed on the road, she must of course pass her driving test – virtually in our interactive driving simulator RODOS (RObot based Driving and Operation Simulator). But first, a real human takes a seat there to collect physical measurement data and provide input for the simulation software. The interaction between the driver and the seat is investigated, for example the pressure distribution. This data should help to better answer fundamental questions about autonomous or semi-autonomous driving: How quickly should the tilted backrest of a seat be raised again with the integrated electric motor system? Does the turned seat return to its original position? How long does it take for the human to take the wheel again when the vehicle signals »Danger from the right, please take over!« in semi-autonomous mode?

The driving simulator is a central component of the Technikum in the division »Mathematics for Vehicle Engineering« and allows the use of different production cabs and real car bodies mounted on a strong robot arm. Currently, the researchers are working on a combined biomechanical-mechatronic model of the coupled seat system, which can be used to parameterize and calibrate the simulation software developed in the EMMA4Drive project.

This means that in the future, certain tests that are primarily aimed at physically stressing the occupants can also be carried out purely virtually, in addition to individual RODOS simulator studies in a real driving cabin. When testing new concepts or comparative investigations of alternative variants, this saves time-consuming hardware modifications. However, for studies in which psychological aspects of the driving behavior are in the foreground, the simulation with RODOS in a realistic cabin environment remains indispensable, since it is crucial for achieving a perfect immersion of the human being into the driving situation.

Video of the »EMMA4Drive« Study in RODOS

In the past few weeks, we have used our interactive driving simulator RODOS to investigate seating positions in autonomous driving. The focus here was on the seating comfort perceived by the test subjects and their perception of safety in an emergency evasive maneuver. The subjects were equipped with a »Full Body Tracking System« and the seat surface was also fitted with pressure sensors. This measurement of body movements helps us to correlate the forces that occur during the evasive maneuver with the subjective comfort perception.

Project Funding

With the project »EMMA4Drive – Dynamic Human Model for Autonomous Driving« the German Research Foundation (DFG) and the Fraunhofer-Gesellschaft are funding the development of a dynamic human model for the development of (partially) autonomous driving vehicles. The aim of the five million euros in funding is to enable companies to participate in innovations from research at an early stage.