Lección No.3 Sonidos y ruidos: una gran diferencia
Lección 1 Ojos para ver!
The goals were to have a precise and intuitive interface. We have also observed that the Haptic WorkstationTMis precise enough to offer a fine control on the blimp’s actuators.
We successfully made a 5 minutes teleoperated flight with a takeoff, and passage over buildings. We did not performed a landing, not because of the lack of control, but because it was too risky. In conclusion, the gesture-based control seems to be a promising technique. The use of a responsive head orientation tracker to drive the video camera is also an efficient method. It allows indeed to have mixed reality video stream coming from the R/C
Blimp that is well positioned into the virtual 3D cockpit. This is also an intuitive way to
move such a camera because it reproduces exactly what happens in the reality. Thus, it increases the believability of the Virtual Cockpit by giving to the pilot the impression that he is inside a real Blimp.
In this chapter, we have successfully implemented two efficient Virtual Reality inter- faces for teleoperation. The use of a two-handed haptic device for simulating the controls is probably not as powerful than two dedicated interfaces. However, it provides the ability to control two different devices. We can also imagine that two or more devices can be teleoperated by the same pilot. Indeed a Virtual Cockpit is easily reconfigurable. Thus a pilot can quickly switch from one to another robot, while autopilots control for a while the rest of the vehicles.
We group these experiments in the category of “unrealistic interaction paradigm”, be- cause we demonstrate that even a state of the art two-handed haptic device is not able to render efficiently simple tools like a steering wheel. The lack of feedback and the underac- tuation is the cause of efficiency problems. The creation of other paradigms solves partially the efficiency issue to the detriment of intuitiveness. In [92], we also proposed an interface
based on the Haptic WorkstationTMto model 3D shapes using metaballs. 3D modeling
is typically a field where there are a lot of metaphors in the interaction paradigms. Our main idea was to find out if we can provide an efficient paradigm that is simply based on hands and gestures. Results are mitigate: the provided method requires too much training and manipulation is thus not as simple as expected. This category shows the limits of a two-handed haptic device like the Haptic WorkstationTM.
Part IV
Synthesis
Chapter 9
Conclusion
W
E BELIEVE THATtwo-handed Haptic feedback is a wide topic which is still under exploration. When Guiard analyzed human bimanual action, he proved that the vast majority of human manual acts involve two hands acting in complementary roles [55]. However, in Haptics, the majority of undergone experiments involve only one hand, or even one finger. In this thesis, we made preliminary studies on two-handed haptic feedback focusing, on the one hand, on the realistic rendering for manipulation, and on the other hand, on its applications.9.1
Summary
In this thesis, we first have presented, in chapter 2, a review of the existing haptic devices, which can be separated in two main groups: tactile and kinesthetic devices. We also pro- posed a review of the Virtual Reality applications that take advantage of the force feedback and 3D interaction provided by kinesthetic devices. At the end of the chapter, we presented works related to whole-hand and bimanual interaction, from a cognitive and computer sci- ences point of view. Our main conclusion was that there is a clear lack of two-handed whole-hand haptic systems.
In chapter 3, we studied the needs to interact in a natural manner with a Virtual En- vironment. We demonstrated the need to track the two hands –i.e. their posture and position– and to provide force feedback on them. Mechanical haptic devices with such properties are definitively not common. In fact, the only commercially available one, is the Immersion Haptic WorkstationR TM. The others are research products. The end of the chapter describes this device in detail.
The second part of this thesis focused on the software control of the Haptic Workstation. In chapter 4, we presented an optimized method to access to the device in order to retrieve useful data as fast as possible. However, it is impossible to use the data in this form because it is not calibrated. For this reason, we presented also fast registration methods suiting the needs of realistic haptic manipulation. Finally, in this chapter, we proposed a software
method to improve the user’s comfort while interacting with Virtual Environments. This strong base eases the creation of the remainder of the haptic rendering software.
In chapter 5, we proposed and described MHaptic. MHaptic is a multithreaded library that handles the haptic rendering and the animation of virtual objects. First, we presented a study on the general structure of the library. We described the modules that are working together in different threads, and the ways to achieve an efficient synchronization between them, in order to maintain high refresh rates and data integrity. We then presented the opti- mized techniques used in the collision detection and realistic animation modules. Finally, we proposed our haptic hand model which is based on a mass-spring system managed by the physics engine. The model eases force feedback computation and allows generic manipulation of virtual objects.
In chapter 6, we proposed techniques allowing a user to interact with any Virtual En- vironment. The fact is that existing Virtual Environment models usually do not contain properties needed to compute force feedback. Starting from this observation, we presented a study on the parametrization of the mass-spring hand model and of the virtual objects in order to ease the grasping and to improve user’s feeling. Then, we proposed and de- scribed a software, the Haptic Scene Creator whose role is to edit an existing visual Virtual Environment in order to add these missing properties.
In the third part of this thesis, we presented experiments in some applications that we believe they can take advantage of two-handed haptic rendering. We separated these experiments into two groups. The ones that feature a realistic interaction paradigm, and the others. In chapter 7, we performed a study on two-handed haptic feedback in a Mixed- Reality Environment. We then presented other applications that allows interaction with some kinds of non-rigid objects.
Finally, in chapter 8, we proposed a study on applications that do not necessarily need a realistic interaction paradigm. We conducted two experiments in the field of teleoperation. The first one consisted in driving a small robot. We performed a study on four interfaces that combines visual feedback with two-handed 3D interaction. Then, we proposed a sec- ond teleoperation experiment using an aerial robot.