Patent Application
20090153365
1. Field of the Invention
The present invention relates to a human-computer interface device.
In particular, the invention relates to a human-computer interface device of haptic type, i.e. capable of transmitting to an operator force and tactile sensations at the fingertips. Among the fields of application the following can be cited: entertainment, development of arts and culture, industrial design, education, marketing and on line sales of goods, telecommunication, etc.
2. Description of the Prior Art
As well known, virtual reality is a particular type of human-computer interaction, capable of creating a virtual environment in which the presence of objects is simulated by a computer. In fact, it is possible to use a computer for creating an environment with virtual walls and virtual surfaces of objects with which a user can interact by an interface device.
A haptic interface is a particular electromechanical device for improving the level of immersion of the user in the above described virtual reality, giving the impression. of touching the environment created by the computer.
Two cases of haptic interaction are commonly distinguished:
In case of simulation of an indirect haptic interaction, the presently known haptic interface devices have an end effector that is conformed as a tool, in order to stimulate in a realistic way tactile receptors of the operator. In case of simulation of direct interaction, the presently known haptic interface devices have end effectors, such as thimbles, handles etc., permanentely in contact with the operator. This condition has the drawback of negatively affecting a realistic stimulation of tactile receptors of the user. The user is, in fact, permanentenly in contact with an interface element of the device even when in the virtual space no contact with objects occurs.
Therefore, in the known systems it is not possible to generate a realistic perception of a transition between non contact and.contact, essential in case of a simulation of a gripping action or a tactile exploration of an object. In fact, the receptors on the fingertips of the user are already saturated by the presence of the haptic interface, which should, but is not, inherently transparent. Therefore, when the known systems are used for simulating direct interaction—for example recognizing the shape of an object by the fingertips—they provide unrealistic haptic sensations, comparable to those generated in a real environment when extraneous elements are held or worn, such as the thimbles.
Among known haptic interfaces, which aim to overcome the limits of the above described products, a device exist proposed by Y.Sato T. Yoshikawa Y. Yokokohji, N. Muramori: “Designing an encountered-type haptic display for multiple fingertip contacts based on the observation of human grasping behavior. In Proceedings of the 2004 IEEE International Conference on Robotics and Automation—New Orleans, La.—April 2004”. This device has movable surfaces that orient themselves as a plane tangential to the virtual object at the point of contact with the limb of the operator. The device has a base that is fixed with respect a workspace and is called “encountered interface”. It is based on the hypothesis that the recognition of the shape depends on the sensation of dragging the fingertips on the surface of the object and on the movement of the area of contact at the fingertip. Furthermore, it is based on the hypothesis that the recognition of the shape depends on the perception of the orientation of the surface of the object at the point of contact.
Such a haptic interface device has the drawback of requiring a calculation of the trajectory of the robotic device that must follow the user, by positioning the movable surfaces in suitable points of the space without interfering with the operator.
Further drawback is the dependence of the workspace of the device from the size of the virtual object. In particular, the simulation of a large device requires a correspondingly large workspace. Therefore the device is cumbersome and heavy, and also bulky and heavy are the actuators necessary to its operation.
It is then a feature of the present invention to provide a haptic interface device suitable for recognizing virtual forms that is inherently transparent leaving a fingertip free of moving so that the fingertip can receive a realistic tactile sensation only when it reaches the points that belong to a virtual surface.
It is another feature of the present invention to provide a haptic interface device capable of simulating realistically the sensations on the fingertips that derive from the transition between a situation of not contact to a situation of contact and vice-versa.
A further feature of the invention is to provide a haptic interface device capable of transmitting to an operator an amount of tactile information data higher than traditional haptic interface devices.
Furthermore, it is a feature of the present invention to provide a haptic interface device capable of causing a user to perceive the local orientation of a virtual surface, in a remarkably shorter time than in the prior art.
Another feature of the invention is to provide a haptic interface device with encumbrance, weight and energy consumption that are reduced with respect to the known devices.
It is still a feature of the invention to provide a haptic interface device with shape and size such that it is easily portable, and in particular without any mechanical connections with a base of a support fixed with respect to the workspace, light, not much cumbersome and with low energy consumption.
A further feature of the invention is to provide a haptic portable interface device capable of being mounted on the structure of existing haptic interfaces, increasing the number of haptic information data transmitted to an operator.
These and other objects are achieved, according to the present invention, by a haptic portable interface device, which can be fixed to a hand in order to be integral to a finger, each finger having a fingertip, said device being characterised in that it comprises:
In particular, said connection element is selected from the group comprised of:
In particular, said means for approaching/withdrawing said orientable surface comprises an articulation having a first end connected to said orientable surface and a second end pivotally connected to said support.
In particular, said at least one orientable contact surface belongs to an orientable plate.
This way, during the phase of free movement when the fingertip is not in contact with the virtual surface, said plate is kept at a distance from said user's fingertip, whereas during the transition between the non contact and contact with the virtual surface said plate is brought to touch said fingertip, assuming orientations of a plane tangential to the virtual surface in the point of contact.
This way, when moving in a free space, the user does not feel any tactile sensations on the fingertip, improving the rate of transparency of the device. Instead, when an interaction occurs with the virtual surface, tactile information is provided as presence, position and orientation of the area of contact and approaching direction of the fingertip with respect to the virtual object.
In particular, the approaching direction adds a realistic content to the tactile sensation, and this can be obtained causing the plate to approach the fingertip in the same relative approaching direction between fingertip and virtual surface.
Further advantage of the present invention is the workspace necessary to the movable surface with respect to the connection element that is in any case limited and independent from the size of the virtual object. Advantageously, said haptic interface device is mounted on several fingers of a hand, so that on each finger a corresponding haptic interface device operates. This way, using such a device for more fingers or a device for each finger of a hand, the user has a realistic sensation of the shape of a virtual object. Furthermore, since the plate touches the user only in case of actual contact in the virtual environment, in any desired circumstances the haptic interface device is completely transparent.
Preferably, said contact surface comprises a plurality of microactuators, said microactuators recreating completely the local geometry of said virtual surface. This way, said microactuators communicate to the user data concerning the local geometry of a simulated object, such as roughness and surface relief, giving sensations that are added to the already cited sensations of presence, position, orientation of the area of contact and approaching direction of the fingertip with respect to the virtual object.
In particular, said microactuators are tactile effectors.
In a preferred exemplary embodiment, said means for orienting said orientable surface comprises a parallel kinematic mechanism. In particular, said parallel kinematic mechanism provides:
This way, said orientable surface remains always tangential to a sphere with centre located in said central point.
In particular, said means for causing a rotation to said first and second base links comprises:
In particular, said returning resilient means comprises a torsion spring.
Preferably, said flexible cable is pulled by an electric motor located remotely from said haptic interface device.
In particular, said means for approaching/withdrawing said orientable surface to/from said fingertip comprises:
Preferably, said means for moving said movable base with respect to said fixed base comprises a plurality of limbs connected between said fixed base and said movable base, said limbs moving said movable base changing its own length.
In particular, said limbs comprise:
In particular, said means for moving said second end with respect to said first end comprises:
Advantageously, said returning resilient means comprises a compression spring.
In particular, said fixed base is axially symmetric and concentric to said connection element.
In a preferred exemplary embodiment said movable base has substantially annular shape and is substantially concentric to said fixed base and said support element.
In particular, said plurality of limbs comprises three limbs arranged symmetrically with respect to the axis of said fixed base.
Advantageously, said means for detecting the spatial position and the orientation of said support, with respect to a reference system are selected from the group comprised of:
The invention will be made clearer with the following description of some exemplary embodiments thereof, exemplifying but not limitative, with reference to the attached drawings wherein:
In the following description, according to the invention, a human-computer interface device of haptic type is shown, i.e. capable of transmitting to an operator force and tactile sensations at the fingertips. More in detail the interface device is capable of orienting in space about a point an orientable surface and of approaching/withdrawing it to/from a fingertip, giving to an operator a tactile sensation to become aware of the shape of a virtual surface, in particular reproduced from a real surface. Furthermore, the haptic interface device, by touching the user's fingertip only at virtual points of contact with the real surface and reproducing a tangential orientation to this virtual surface in the point of contact, gives any tactile sensations on the fingertip during the motion in a free space, obtaining a very high level of transparency of the device. Furthermore, additional tactile sensations can be felt, such as the approaching direction, the orientation and the position of the area of contact and the relief of the surface. The workspace of the interface device can be very wide using suitable systems of position tracking.
In
More in detail,
This way, the orientable surface 24 remains always tangential to a sphere not shown with centre located in said central point 66.
The above described base link comprises: a substantially cylindrical lateral surface, respectively indicated as 55 and 58, co-axial and integral to each respective base link; a flexible cable not shown in the figure, connected and partially wound on this surface 55 and 58; the corresponding base link when this cable is pulled; and a torsion spring suitable for causing the base link to return in the respective starting position when the cable is released.
In a structural form of the invention, that a skilled person can reach using normal experience, the many actuating links can be arranged in order to have positions of minimum encumbrance for a user.
Notwithstanding, furthermore, the annular support to the finger is put on distal phalanxes, it is not excluded that it is mounted elsewhere, for example on the palm of a hand, at the wrist, etc. In this case the support and the fingertip should be integral to each other.
Concerning the tracking system, it can be of the type with stiff articulated links, as shown in
The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of. the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
| Number | Date | Country | Kind |
|---|---|---|---|
| PI 2004A000084 | Nov 2004 | IT | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB05/03460 | 11/18/2005 | WO | 00 | 6/6/2007 |
