Samira – not the mythical name of a Persian princess – but a virtual assembly process capable not only of rendering a 3D image of objects but of reproducing the tactile sensations induced by manipulations, especially shocks and friction. A brief incursion into the world of virtual reality...
An operator manipulates the end of an articulated mechanical arm, which he moves in order to perform a complex assembly operation in a confined space. He observes the result of the manipulations on a computer screen, which displays the image in 3D. Whenever his ‘virtual hand’ touches a ‘digital object’, a command is sent to the motors of the mechanical arm, which immediately simulates actual contact and thus generates resistance felt by the operator. The operator owes this sensorial feedback to the Samira (SimulAtion de Maintenance Interactive avec Retour hAptique) system developed by EADS Innovation Works.
This feedback is made possible by the properties of the articulated mechanical arm which, thanks to slaved motors, coupled with sensors and electronics, possesses six degrees of freedom (three in rotation, three in translation). The arm combines highly complex mechanisms and software and was developed by Haption, an industrial offshoot of the French Atomic Energy Commission (CEA).
Commented Nicolas Chevassus, who heads the Product Engineering IT department at EADS: “As a rule, in the virtual world, the mouse allows us to skip over an obstacle or to overlay, in a seemingly impossible way, two incompressible objects within the same space. With Samira, the reality of contact with the object is added to 3D viewing. In other words, one introduces an audible and tactile perception of contact or collisions that eliminates this physical coincidence among objects.”
The Samira concept, which was developed by the central laboratory of EADS Innovation Works's at the request of Airbus, required two years of effort. The project also called upon the services of several software companies, including the French Virtools concern.
A twofold tour de force was required of Samira’s creators. First, in rendering manual motion, Samira’s goal is to facilitate use of the robotic tool as much as possible to ensure it faithfully reproduces natural gestures of the hand without requiring prior training. A second obstacle concerns feel feedback: here a multiple-sensor interactive setup eliminates all feedback interpretation effort or any possibility of error. Thanks to a special screen enabling a 3D effect to be obtained without special glasses, coupled with touch and sound feedback, the system requires no effort on the part of the operator to interpret the effect of their maneuvers. Thus Samira detects contact between objects, including friction, in virtual reality and generates realistic real-time tactical responses.
The tactile system gives engineers a more realistic experience than conventional viewing systems in simulating assembly or maintenance operations, making possible improved analysis of maintenance tasks, especially in the case of complex systems. Says Nicolas Chevassus: “The benefits to be derived from Samira could be immeasurable. Validating an assembly-disassembly study that used to require over a week with conventional methods could now be completed in only a few hours.”
Even though Samira is not yet on the market, its dissemination within the EADS group is of interest not only to Airbus (for virtual maintenance) but also to Eurocopter and other EADS units throughout Europe. The system will soon become an indispensable tool for validating solutions in maintenance studies. It could also prove extremely useful for learning engineering-related motions when training operators. Beyond this, other applications can be glimpsed in fields such as medicine for simulating surgery, or in next-generation video games, where force feedback promises to be extremely realistic.
The next stage in enhanced realism could be reached by further improving interaction with the user. At present we know how to render tactile sensation of the hand, but not yet of each of its fingers. In France and the United States, researchers are thinking already of ‘data gloves’ capable of rendering the full gamut of the human hand’s touch to the virtual world.
An operator manipulates the end of an articulated mechanical arm, which he moves in order to perform a complex assembly operation in a confined space. He observes the result of the manipulations on a computer screen, which displays the image in 3D.
