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HAPTION
Physics simulation applied to ergonomic studies
A brand new approach to ergonomic studies
Traditionally, ergonomic studies are based on the observation of movements and postures,
and their assessment using scoring rules (RULA, OCRA, EAWS, etc.). Such an observation
is often supported by video recording devices, so that movements can be analyzed “frame by
frame” and documented. There are two major drawbacks to that traditional approach: first, it
is highly subjective and depends on the expertise of the person giving the scores; second,
the equipment or the work environment need to be physically available.
In the last ten years, simulation tools have been proposed and implemented in industry for
ergonomic studies. For example, the technology SAFEWORK™ which was then purchased
by Dassault Systemes and integrated into the DELMIA™ brand. Its functionalities allow
design engineers to place virtual human operators inside a factory in 3D, and determine
RULA scores. Such tools pave the way toward a “human-centred” design of products (from a
user point of view) and manufacturing processes (from a worker point of view).
RULA score assessment for a worker inside Delmia V5™
HAPTION – Atelier relais, ZA Route de Laval, 53210 SOULGE SUR OUETTE – France
℡ +33-243645120 –
+33-243645121 –
[email protected] –
http://www.haption.com
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However, those new tools are not easy to use. A real expertise in CAD (Computer Aided
Design) is necessary, so that they are of little benefit to ergonomists. Especially, the key
frame animation of virtual operators is a very slow process (typically 4 hours for 3 minutes of
animation), and its results are not very convincing (stiff movements, “robot-like”).
This is where HAPTION comes into play, with the technology called “interactive physics
simulation”. The technology is developed by CEA LIST (French Atomic Energy Commission)
and integrated by HAPTION into Dassault Systemes’ industrial software products. Its role is
to compute the physical interactions of the virtual operators with their environment in realtime. When associated with a motion capture system, it makes it possible to control the
virtual operator with natural movements and realistic physical interaction.
Operating principle
The IPSI technology (IPSI stands for “Interactive Physics Simulation Interface”) proposed by
HAPTION belongs to the software category of real-time “Physics Engines”. Real-time physics
engines have known a very fast development in the last few years, driven by the video
games industry. The specific characteristics of IPSI are its ability to handle very complex 3D
geometry, and to guarantee that 3D objects don’t interpenetrate at all during the simulation.
The operating principle is the following: starting from the CAD definition of the environment
objects and of the virtual operator, IPSI builds an optimized internal representation; after the
simulation is started, it solves a system of equations which includes the contact constraints
between objects and the partial information about the posture of the real operator; it obtains
the complete posture of the virtual operator, which does not violate the non-interpenetration
constraints between objects; finally, it updates the posture of the manikin in DELMIA™.
Real operator
equipped with markers
Physical doll
simulated by IPSI
Virtual operator
animated in DELMIA
The virtual operator follows the movements of the real operator, as long as it doesn’t collide
with an obstacle in its environment. In case it encounters an obstacle, it adapts its posture so
that it does not go through, or it stops the movement which would violate the noninterpenetration constraint. As a consequence, the animation of the virtual operator is
geometrically valid. In addition, IPSI guarantees that the posture of the virtual operator is
valid from a kinematic point of view. Further yet, in case of a conflict IPSI always converges
to the solution of least energy, which usually corresponds to the most natural posture.
HAPTION’s solution supports the major motion capture systems, both optical and inertial:
ART, Vicon, Motion Analysis, XSens, and many legacy tracking devices through the trackd
software by Mechdyne. It’s also possible to combine motion capture with haptic interfaces, so
that the real operator can feel contact forces with virtual objects. Finally, the addition of a
Head-Mounted Display (HMD) provides a complete immersion inside the 3D environment.
HAPTION – Atelier relais, ZA Route de Laval, 53210 SOULGE SUR OUETTE – France
℡ +33-243645120 –
+33-243645121 –
[email protected] –
http://www.haption.com
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Complete visual, gesture and haptic immersion
(picture © Lockheed Martin Aeronautics, Fort Worth, TX, USA)
Benefits of HAPTION technology
With the technology proposed by HAPTION, ergonomic studies can be carried out very early
during the design process of a new product. Its added value is multiple:
1. The real operator conducting the simulation does not need any expertise in the
domain of CAD; as a consequence, he can be a real worker coming from the shop
floor, who will contribute with his real-world experience.
2. The animation results are displayed immediately, in real-time; therefore, it is possible
to detect problems, propose solutions and validate results in a tight iterative loop, fast
and dynamic.
3. The postures and movements are controlled by a real operator, thus really realistic;
the simulation results have a much better quality than classical key frame animation.
4. Because of the “scale 1:1” approach, the real operator must himself take the postures
and do the movements which are necessary for achieving the task; he can then give
an immediate feedback on the comfort and difficulty of the operations.
5. More generally, the work sessions become much more interactive and productive; all
functions (style, design, methods, industrial hygiene and safety) can meet around the
same simulation environment, and work together towards enhancing the work
conditions and optimizing the use of equipment.
HAPTION – Atelier relais, ZA Route de Laval, 53210 SOULGE SUR OUETTE – France
℡ +33-243645120 –
+33-243645121 –
[email protected] –
http://www.haption.com
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Multidisciplinary working session
(picture © United Space Alliance, Kennedy Space Center, FL, USA)
Technical implementation
The proposed technology is available for the software platforms CATIA V5™ and DELMIA
V5™ by Dassault Systemes. HAPTION supports all versions from R18 to R21, for Microsoft
Windows 32 and 64 bits. The typical configuration of the workstation is given here below:
- CPU Quad-Core @ 3GHz
- 16 GByte RAM
- Graphic board NVidia QuadroFX™ 3800 or ATI FirePro™ 7800
- Microsoft Windows XP/7 64 bits
For very complex models (several virtual operators, large workspace, large number of
triangles), it is advisable to relocate the IPSI component on a dedicated workstation.
About HAPTION
Since its creation in 2001, HAPTION has been developing and selling hardware and software
solutions based on force-feedback. HAPTION uses patented technologies developed by
CEA LIST (French Atomic Energy Commission), for which it has an exclusive worldwide
license. Its activities span the sectors of research laboratories and universities (CNRS/INRIA,
University of Karlsruhe, Iowa State University, Politecnico di Milano), transport industries
(PSA Peugeot Citroën, Airbus, BMW, Volkswagen, Boeing, Lockheed Martin, Sikorsky) and
nuclear operations (CEA, AREVA, Cybernetix, ITER).
HAPTIONS employs 15 people in its facilities near Laval, France. In 2010, the turnover was
1.6 M€, 48% of which outside of France.
HAPTION – Atelier relais, ZA Route de Laval, 53210 SOULGE SUR OUETTE – France
℡ +33-243645120 –
+33-243645121 –
[email protected] –
http://www.haption.com