WO2007045804A2

WO2007045804A2 - Robotised three-dimensional vestibular stimulator

Info

Publication number: WO2007045804A2
Application number: PCT/FR2006/051073
Authority: WO
Inventors: Pierre-Paul Vidal
Original assignee: Universite Rene Descartes - Paris 5; Centre National De La Recherche Scientifique
Priority date: 2005-10-21
Filing date: 2006-10-20
Publication date: 2007-04-26
Also published as: FR2892293A1; FR2892293B1; WO2007045804A3

Abstract

The invention relates to a robotised three-dimensional vestibular stimulator (1) comprising a platform for a subject to be stimulated. According to the invention, the platform (2) can be rotated on a platform support (4) which is essentially parallel to the platform and which is fixed to a first end of an essentially-perpendicular first rigid lever arm (5), the second end thereof being fixed to a vertical carriage (7) by means of a first ball joint (6). A second lever arm (8), which is perpendicular to the first arm, is rigidly connected to the second end of the first arm. The free end of the second lever arm (8) is fixed by means of a second ball joint (10) to a first end of a first linear rolling actuator (11) which is disposed laterally in relation to the platform support, the second end of said actuator being connected by means of a third ball joint (12) to a first reference point. In this way, the first (5) and second (8) lever arms take the form of an L such as to enable the ball joint (6) to perform at least one rotational movement and the platform support (3) to perform at least one swinging movement essentially in the plane of the first linear rolling actuator (11). The vertical carriage (7) is actuated by a linear vertical translation actuator (13) which is fixed to a horizontal carriage (14) such as to enable the second ball joint (10) to perform at least one rotational movement and the platform support to perform at least one swinging movement in the plane of the linear vertical actuator as well as a horizontal translation movement.

Description

Robotic three-dimensional vestibular stimulator

The present invention relates to a robotized three-dimensional vestibular stimulator. It has applications in the field of research, tests and studies, including vestibular function in subjects of study.

Three-axis automated positioning devices are already known, such as ACUTRONIC AC3350 series devices which allow any angular positioning in yaw, pitch and roll. ). These devices are however relatively bulky, expensive and intended to test measuring devices such as gyroscopes. The present invention proposes the implementation of means resulting in a cost reduction while allowing to obtain good performance in the possible positions. It can be declined in various ways including the carrying capacity on the plate holder subject.

The invention therefore relates to a robotized three-dimensional vestibular simulator comprising a plate for a subject to be stimulated, said plate being able to be set in motion by actuators according to kinetic evolutions in a three-dimensional space over time and with respect to a fixed reference system. .

Preferably the evolutions are controlled by a computer means.

According to the invention, the plate is movable in rotation (for yaw movement), a plate actuator, fixed on a plate support substantially parallel to said plate, being able to rotate in one direction or the other said plate around the plate. an axis of rotation perpendicular to the plate, the plate support is fixed (by the periphery) to a first rigid lever arm substantially perpendicular to the platen support by a first end of said first lever arm, the second end of said first lever arm being fixed by a first ball joint to a vertical carriage, a second lever arm perpendicular to the first arm of lever being rigidly attached to the second end of the first lever arm, the free end of the second lever arm being fixed by a second ball joint at a first end of a first linear roll actuator disposed laterally with respect to the table support and whose second end is connected by a third ball joint to a first point of the reference frame, the first lever arm and the second lever arm thus having an L shape (in the same plane, with a free end of the second lever arm possibly folded 90 ° forward), the first roll actuator allowing during its movements at least one rotation of the first ball and at least one swing motion (in roll) of the platen support substantially in the plane of the first linear roll actuator, the vertical slide is actuated by a linear vertical translation actuator (pitch and or verticality) of substantially vertical general direction itself fixed rigidly on a horizontal carriage to allow during the movements of the vertical carriage at least one rotation of the second ball (and the fourth ball joint in the case where a second linear actuator of roll is implemented) and at least one swinging motion (pitching) of the tray support in the plane of the vertical linear actuator, the horizontal carriage being actuated by a linear horizontal translation actuator of substantially horizontal general direction rigidly fixed in at least a third point of the reference frame to allow during the movements of the trolley hori zontal displacement in horizontal translation of the linear actuator of vertical translation (of pitch and / or verticality). In various embodiments of the invention, the following means can be used alone or in any technically feasible combination, are employed: - the free end of the second lever arm is bent at 90 ° (forward ) in the general plane of said second lever arm so that the second ball is substantially in a plane perpendicular to the plate comprising the axis of rotation of said plate and parallel to the first lever arm, - a third lever arm perpendicular to the first arm of lever is rigidly attached to the second end of the first lever arm on the opposite side and in the extension of the second lever arm, the free end of the third lever arm being fixed by a fourth ball joint at a first end of a second actuator linear roll disposed laterally and opposite to the first roll linear actuator relative to the tray support and whose dry wave end is connected by a fifth ball joint to a second point of the reference frame, the first lever arm, the second lever arm and the third lever arm thus having a T-shape, the first linear roll actuator and the second linear actuator rollers operating complementary to one another; the free end of the third lever arm is bent 90 ° (towards the front) in the general plane of said third lever arm so that the fourth ball is substantially in a plane perpendicular to the plate comprising the axis of rotation of said plate and parallel to the first lever arm, preferably the two free ends of the second and third lever arms are bent at 90 ° (towards the front), free ends of the second and third lever arms are bent at 90 ° in the general plane of said second and third lever arms so that the second and fourth ball joints are substantially in a plane perpendicular to the plate, comprising the axis of rotation of said plate and parallel to the first lever arm,

- The tray support, the first, second and third lever arm form a nacelle at least open on the front and the top, two reinforcements being disposed between the curved free ends of the second and third lever arm and the tray support ,

the actuators are disengageable,

the actuators are lockable in a predefined position, the second ball joint and the possible fourth ball joint can be dismounted in order to be able to separate the first linear roll actuator and the possible second linear roll actuator from the free ends of their corresponding lever arms; the kinetic evolutions can be chosen from yaw, roll, pitch, vertical translation and horizontal translation movements possibly in combination,

at least one rotating electrical connection is implemented between the plate and the tray support,

the tray actuator is omitted, the tray being directly fixed rigidly to the tray support,

the linear actuators comprise in parallel a rotary rack-and-pinion motor in parallel with a gas cylinder, the subject surface of the object-carrying plate is directed upwards towards the first lever arm,

- the subject surface of the subject holder is facing downwards, opposite to the first lever arm, (the subject can be put upside down) - the subject holder is removable so that it can be installed in such a way that that the subject surface of the subject-carrier plate is directed upwards towards the first lever arm, or so that the subject surface of the subject-carrier plate is facing downwards, opposite the first arm lever, (the subject can be put upside down) the subject holder plate is interchangeable,

at least one of the points of the reference frame for fixing the second end of the first and / or of the possible second linear roll actuator is displaceable, (corresponds to the third ball and / or fifth ball)

the subject is an experimental animal with a maximum weight of approximately 35 kg,

the maximum horizontal translation of the horizontal actuator is approximately 400 mm, the maximum vertical translation of the vertical actuator is approximately 400 mm,

- the rotation is unlimited,

the roll is limited to approximately +/- 20 ° with respect to the vertical, the pitch is limited between approximately + 80 ° forwards and -20 ° for the rear relative to the vertical,

the actuators further comprise position encoders.

The present invention will now be exemplified without being limited thereto with the description which follows in relation to the following figures: FIG. 1 which represents front view from the front an embodiment of the vestibular stimulator according to the invention with two linear roll actuators, Figure 2 which shows a side view of the same embodiment of the vestibular stimulator according to the invention with two linear roll actuators, Figure 3 which schematically shows a linear actuator, Figures 4 to 6 which give curves. Stimulator response, Figures 7 to 12 which give geometrical representations of the positions of the pacemaker organs for analysis of the capacitances and arrangement of the stimulator organs. The stimulator of the invention makes it possible to move a subject, in practice an animal, placed on an experimental platform to perform vestibular stimulations or other types. The permitted elementary movements of the plateau that supports the subject of experimentation are: a yaw motion, a vertical motion, a horizontal motion, a rolling motion about a fixed axis, and a pitching motion around the plane. a virtual axis. Some combinations of these elementary movements are possible.

In the following description of possible elementary movements of an exemplary embodiment of the invention, the term axis is used to name the actions of each of the actuators. Thus, the stimulator here presented in relation to the Figures comprising five actuators, there will be five axes, a rotating axis for the plateau actuator and four axes in translation in various orientations according to the possible combinations for the linear actuators. Thus, an operating mode using the five axes is possible with a combined three-axis horizontal movement, a three-axis combined vertical movement, a two-axis combined rolling motion, a three-axis combined pitch motion and a two-axis movement. pure lace combined according to four axes. The potentially functionally effective actuators are then: the plateau actuator (rotation: yaw), the first linear roll actuator, the second linear roll actuator, the linear vertical translation actuator and the linear horizontal translation actuator.

An operating mode using three axes is also possible with pure horizontal movement, pure vertical movement and pure horizontal yaw movement. In this three-axis mode, the first and second roll linear actuators arranged laterally by with respect to the plate are disengaged and, preferably, are disconnected from the free ends of the second and third lever arms at the second and fourth ball joints, there remains only potentially functionally effective that the plate actuator (rotation: lace), l vertical translational linear actuator and horizontal linear translational actuator.

In FIG. 1, seen from the front, and FIG. 2, side view, the stimulator 1 implements two linear roll actuators, a first 1 1 and a second one 19, connected at their first ends in a removable manner by second 10 and fourth 18 ball joints at the upper part of a cage having at its lower part a tray support 4, a rotational actuator 3 of a carrier plate 2. The cage is formed of a first lever arm 5 and two other lever arms perpendicular to the first, a second 8 and a third 16 with free ends bent forwards 9, 17 for attachment to the ball joints 10, 18, this assembly having a general T-shape front view . Lateral reinforcements parallel to the first lever arm complete and reinforce the cage. A first ball joint 6 connects the upper end of the first lever arm 5 to a vertical linear actuator carriage 13, the latter being itself integral with a horizontal linear actuator carriage 15. The second ends of the first 1 1 and the second 19 roll actuators are connected to points of the frame by a third 12 ball and fifth ball.

For the examples of dynamic characteristics of the stimulator which are given later a stimulator having approximately a lateral impasto in width of 1.20m, in depth of 1.30m and in height of 1.10m was considered as shown in FIGS. Figures 1 (front view) and 2 (side view) and linear actuators 400mm stroke. 1, dimension B, the distance between the second ball (at the first end of the first roll linear actuator) and the fourth ball (at the first end of the second roll linear actuator), is about 40 cm. 2, the dimension A, the distance between the first ball 6 and the axis joining the second ball to the fourth ball 20, is about 20 cm.

Figure 2, dimension C, distances between the subject plate and the axis joining the second ball to the fourth ball (substantially the length of the first lever arm minus the distance between the table support and the door plate). subject), is about 20cm.

With regard to the pure yaw movement corresponding to the rotation of the platen relative to the platen support by the platen actuator, the rotation is infinite (> 360 °) and, preferably, an angular encoder is implemented in order to to know the angular position (modulo 360 °) of the plate with respect to the support of plate. The tray and the tray support are substantially parallel to each other and the axis of rotation perpendicular to the plane of the tray. The maximum speed of rotation of the plate is about 1636 ° / sec but depends on the actuator implemented (and possibly the encoder in case a retro-control rotation is implemented). Both directions of rotation are possible. Preferably the tray is aluminum or plastic for maximum relief. The tray may have anchor points or lines (fixing groove) for attaching the subject and measuring equipment. Preferably, an 18-circuit rotating joint is integrated in the plate with a connector for connection of the measurement circuits (insertion resistor 10mΩ @ 6Volts - 5OmA and a capacity of 2A maximum per circuit for 6.10 ⁶ maneuvers). In a variant, the implementation of a radio transmission equipment and autonomous power supply or by induction (a transmitting coil in the tray support and a receiver coil in the tray) makes it possible to dispense with the rotating joint.

With regard to the pure roll movement, which consists in the plate having a lateral swinging movement (from right to left) substantially in the plane passing through the first 1 1 and second 19 linear roll actuators arranged laterally with respect to the plateau can be implemented a combination of two axes with rotation around the first 6 ball in a fixed vertical point. It is also possible to implement a combination of three axes with rotation around the first ball-and-socket joint at any point on a vertical or horizontal line depending on whether the vertical linear translation actuator 13 or the horizontal linear translation actuator 15 is used. Finally, it is possible to implement a combination of four axes with rotation around the first ball in any point of a vertical fore-aft plane (perpendicular to the plane passing through the first and second linear roll actuators) using the both the linear vertical translation actuator and the linear horizontal translation actuator. In this example, the swing is limited to about +/- 20 ° with respect to the vertical.

With regard to the pure pitching movement which consists of the plate having a front-rear (anteroposterior) swing movement, it is the vertical linear translation actuator 13 which allows this movement, the curved free ends 9 , 17 second and third 16 lever arms being rotated at the second 8 and fourth 18 ball joints. Here again, it is possible to implement several combination of axes according to whether or not the linear horizontal translational actuator 15 and / or the first and second roll linear actuators are actuated to move the rotation point of the linear actuators. second 10 and fourth 18 ball joints at other vertical positions (also moving parallel the average position point the linear actuator vertical translation in the case where the axis joining the second and fourth ball joints remains fixed, and in a variant it can also oscillate). In this example, the swing is limited to about + 50 ° forward and -20 ° backward from the vertical.

As far as the pure translation movement is concerned, several possibilities exist depending on the number of axes used: the linear vertical translation actuator alone to vertically move the plate (vertical translation movement), the linear horizontal translation actuator only to horizontally move the plate (horizontal translation movement) or, still, the vertical linear translation actuator and the horizontal linear translation actuator together to move the plate in a vertical anteroposterior plane. If such a pure translational movement is desired, it is possible either to disengage the first and second linear roll actuators arranged laterally with respect to the plate, or, preferably, to disconnect them from the free ends of the second and third lever arms. at the level of the second and fourth ball joints.

The maximum speed per axis (linear actuators) is about 1 m / s for an accuracy of 1 / 10mm. A linear actuator is shown in Figure 3 and has two ends that can be moved away or approximated linearly. At each end is fixed a ball 20 for the transmission of linear movement and rotational movements. The linear actuator comprises a housing 26 in which slides a rack 21 guided by balls 23 and actuated by the pinion 22 of an electric motor. A gas cylinder 25 in parallel with the rack allows damping and balancing of mechanical and onboard loads. A retaining stopper 24 is attached to one end of the rack 21. Measuring means of the stroke (not shown) to encoder type incremental (in the example: 1024 points is an accuracy of 1 / 10mm on the stroke of 400mm) allows to know the position of one end relative to the other. For the rotational actuator of the carrier plate, an angular encoder is also implemented.

It will be understood that the values given for swing angles are related to the physical characteristics of the apparatus and in particular the length of the lever arms and the length of the linear actuators. On the other hand, the dynamic characteristics, in particular the maximum rotational and linear frequencies, depend in particular on the capabilities of the actuators and the load on board the carrier. Response curves giving the maximum frequencies of certain movements (pitch, roll, yaw / rotation, translation) as a function of the load on board can be determined. As an example, in FIG. 4, the maximum rotational frequency in degrees / s as a function of the load (triangle) embedded in Kg for a 180 mm diameter object-bearing plate in pitching movement (tiles), roll (FIG. squares) and yaw (cross) at different frequencies in Hz. Figure 5, hanging from the previous one, concerns the case of a 380mm subject holder. These three movements correspond to rotations around a point midway between the points of attachment. Figure 6 relates to linear actuators in general and gives the maximum amplitude of the translation in m (stroke) as a function of the oscillatory frequency in Hz.

The stimulator is under the control of a microcomputer that includes a graphical user interface for programming and / or recording the desired types of movement (roll, pitch, yaw, translations and combinations), their characteristics (in particular amplitudes, frequencies) and evolutions. over time. Thanks to the feedback given by the linear and rotating encoders, the stimulator and microcomputer system can operate in closed loop. In addition, during the programming of the movements, the program can, in an evaluation phase or during the input, determine incompatibilities or impossibilities of movements or movement characteristics (for example, too much pitching amplitude towards the rear which is risky bring the object tray backwards against the vertical linear actuator). Thanks to the graphical input interface, the user can choose individually or in combination the movement (s): rotation of the subject plate, the left roll, the right roll, the vertical translation, the horizontal translation. It can also choose the speeds according to the axes and in rotation as well as the evolutions combined or not: sinusoidal, ramp, square, triangle or others (a module AUTOMATISM of programming of evolution is available which makes it possible to create, record and recover scenarios / motion evolutions scripts) and their characteristics (amplitudes in mm or degrees depending on the case, frequency, duration ...). For example, it is possible to create an automatism to raise the board by 10cm for 3s and then roll with a frequency of 3Hz +/- 4 °.

As a safety measure, in addition to the evaluations or input controls avoiding the impossibilities or incompatibilities, emergency stop means are available both on the graphical interface and on a control panel of the pacemaker itself with in particular a button emergency stop button. The desk in an advanced version also allows the execution of simple functions such as executing the program entered on the microcomputer. Thus, the movements can be controlled individually or several at the same time by buttons on the console.

In return, during the execution of the movements, it is possible to follow the real evolutions of the actuators thanks to the encoders and to be able to record and / or display these evolutions on the screen of the microcomputer.

In addition to the programming possibilities described above, the system can also operate manually depending on the position of a user operated position sensor. This sensor, in a simplified version is the mouse of the microcomputer, and in more advanced versions can be a control lever type "joystick" or a three-dimensional sensor. In the manual mode, the evolutions of the stimulator are either live, depending on the actions of the user, or the actions recorded and restored later. Preferably, the manual mode program detects incompatibilities and impossibilities of movement of the stimulator. We will now detail the possibilities of dynamic evolution of the stimulator described by way of example considering a reference xyz, with y anteroposterior axis (front-back), x axis right-left, z vertical axis, and thanks to geometric representations for calculation. Regarding the positioning of the first and second linear roll actuators (left and right cylinders), due to the presence of said roll actuators and in vertical translation, there is a locking cone. In Figure 7, we consider the case where we want to have a roll and pitch of +/- 20 ° (pitch up to 80 °) with respect to the vertical with, in addition, possible displacements in horizontal of 40cm and vertical 35cm. The minimum displacement Dmin is 59.8cm. To determine this position, we consider the plateau in the worst case (at -20 ° in the plane (Ox ₁ Oz), at -20 ° in the plane (Oy ₁ Oz), Horizontal displacement = 0, Vertical displacement = 92.5cm minimum) and it can be seen that it is necessary that the first and second linear roll actuators are inclined at an angle of 20 ° in the plane (Ox, Oz) and therefore that the second ends of said roll actuators are approximately 19cm on either side of the z axis on the x axis. The diagram corresponding to this case is given in Figure 7 where it can be seen that the lower attachment points of the Left and Right cylinders (third and fifth ball joints) must be fixed at approximately 19cm (19.08cm on Ox) from and some of Oz. To allow translational movements, two possibilities are available: (a) the lower attachment points (second ends) of the cylinders G and D can be moved back about 21 cm (20.92 cm) from the previous position or (b) movements of the Horizontal position may be allowed only between 21 cm and 40 cm when the G and D cylinders are attached at their first ends (upper ends) to the platform nacelle. By cons, cylinders G and D must be detached for strokes H = 0 to 21 cm.

For horizontal and vertical displacement in the absence of roll and pitch and with the lower attachment points of cylinders G and D (third and fifth ball joints) fixed at 19cm (on Ox), the axis joining the second ball joint at the fourth ball joint, that is to say at the upper ends of the cylinders G and D (first ends of the two roll actuators), can retreat 21 cm and advance 19 cm and climb 35 cm without obstacle (if we maintain the horizontally, it does not reach the limit of the blocking cone even if one moves backwards by 21 cm). On the other hand, depending on whether the cylinders G and D are attached to their first ends (upper ends) to the nacelle of the platform or not (the jacks can then be discarded and no longer constitute a limit), different maximum amplitudes can be obtained. Indeed, it can be seen that if the left and right jacks are hooked to the nacelle by their upper ends, these jacks G and D, to follow the movement, must move more than 107.93-70.25 = 37, 68cm whereas the maximum limit of movement is 35 or even 34,5cm in this example. We must therefore limit the vertical stroke of 3 cm by favoring either the top of the race or the bottom of the race, or predict the hooks between 73cm to 108cm. It follows that on the vertical one can have a displacement of 95.5 to 92, 5 + 35 = 127, 5cm (amplitude 32cm). These cases are shown in Figure 8 and 9.

With regard to the pitch from -20 ° to + 80 °, case shown in Figure 10, it is only possible if the virtual point (center of rotation) is almost in the middle of the plateau: Thus the point of hanging (blocking ) the vertical of the board will go to -15cm and advance 13cm while the lengths of the cylinders G and D will go from 85, 12 (-20 °) to 1 17,59cm (80 °) is a movement G and D of 32.5 cm. To achieve this movement, the hook of the plate must vary from 85, 1 cm to 1 17.6 cm on the cylinders G and D. Given that the movement may vary from 34.5 cm, the tray can be hung at 83 cm to go at 83 + 34.6 = 1 17.6cm. If we add the horizontal and vertical movements, we can have a possible horizontal movement between the heights 83cm (a little less in practice) + 23cm (height plate) = 106cm and 92.5cm (minimum height) + 35cm (travel height) = 127,5cm. This makes a vertical deflection of 127.5-106 = 21.5cm. The possible horizontal movement is always 40cm. For pitching movement -20 ° to + 80 °, neither downward (minimum vertical grip) nor upward (maximum jack hooks), nor to the left (risk of reaching the locking cone) , nor to the right (increase of the maximum length of the cylinders).

With regard to a roll-pitch movement of +/- 20 °, case shown in Figure 1 1 (the grip on the vertical is at + 20cm), it should be noted that to be able to achieve +/- 20 ° angles at both roll and pitch, the position of the virtual point should be approximately at the center of the plate on the roll axis. As a result, the position along the Ox axis (right-left) can move at a low frequency of 19cm and along the Oz (vertical) axis of 9cm from 92, 5 + 20 = 1 12, 5cm.

Maximum deltas (deviations) can also be considered for a frequency of 2 Hz for travel speeds up to 1 m / s. The corresponding case has been shown in Figure 12 (compulsory rise of 16cm compared to the minimum height). Let F be the frequency in Hz and t the time in seconds. For a displacement on Ox (right-left), the delta DX is given by resolution of P = DX.cos (t.2.PI.F) and Vmax = DX.2.PI.F, that is with F = 2Hz and Vmax = 1 m / s, DX = 1 /(2.PI.F) = 8cm (Travel of 16cm). Similarly for roll or pitch, we know that +/- 20 ° causes +/- 17.5cm. In the best case, a frequency of 2 Hz therefore implies a variation of +/- 20.8 / 17.5 = 9 °. Since we want to combine these speeds, we have a DX Max of 5cm and a D ° Max of 5 ° for 2Hz. The deflection H is 19cm. The deflection V is also 19cm from 92, 5 + 16 = 108.5cm.

In conclusion, the movements on the left and right cylinders will only be allowed if the horizontal position varies from 21 cm to 40 cm. The horizontal stroke of 40cm is only feasible if the cylinders G and D are free (disengaged or, better, disconnected) and do not produce movement. The maximum pitch (-20 ° to 80 °) will be realized without roll, at a fixed position H = 21 cm, V = 107.5 with the virtual point (15,0). The rolling pitch of 20 ° can be executed between horizontal positions 21 cm to 40 cm (amplitude 19 cm) and vertical 1 12.5 to 121.5 cm (amplitude 9 cm). Movements beyond 2Hz can not vary by more than +/- 5cm. and +/- 5 °. The positions in H and V can vary in a range of 19cm, H from 21 to 40cm and V from 108.5 to 127.5. The length of the cylinders G and D will vary from 83 cm to 1 17.6 cm.

It is understood that the invention can be declined in various ways without departing from the general scope defined by the claims. For example, instead of the actuator (s) lateral rollers are arranged towards the arm, that is to say that the plate is between these roll actuators, it is possible to arrange said actuators upwards (for example fixing the third and fifth ball joints to the ceiling of the room experimentation instead of the ground, or on a frame mounted in height), which gives a greater movement in roll. Likewise the use of other lever arms would allow the implementation of actuator (s) substantially horizontal roll. For example by extending the first lever arm upwards, beyond the first ball joint.

Claims

1. Robotic three-dimensional vestibular stimulator (1) comprising a plate for a subject to be stimulated, said plate being able to be set in motion by actuators according to kinetic evolutions in a three-dimensional space over time and with respect to a fixed reference system, characterized in what:

- The plate (2) is movable in rotation, a plate actuator (3), fixed on a support (4) plateau substantially parallel to said plate, being able to rotate in one direction or the other said plateau around a axis of rotation perpendicular to the plate,

the tray support (4) is fixed to a first rigid lever arm (5) substantially perpendicular to the tray support by a first end of said first lever arm (5), the second end of said first lever arm (5) being fixed by a first ball joint (6) to a vertical carriage (7), a second lever arm (8) perpendicular to the first lever arm (5) being rigidly attached to the second end of the first lever arm, the end free of the second lever arm (8) being fixed by a second ball (10) at a first end of a first linear roll actuator (1 1) arranged laterally with respect to the plate support and whose second end is connected by a third ball (12) at a first point of the reference frame, the first lever arm (5) and the second lever arm (8) thus having an L shape, the first roll actuator (1 1) allowing at its movements at least one r otation of the first ball (6) and at least one swing movement of the plate support (3) substantially in the plane of the first linear roll actuator (1 1),

- The vertical carriage (7) is actuated by a linear vertical translational actuator (13) of generally vertical general direction itself rigidly fixed on a horizontal carriage (14) to allow during the movements of the vertical carriage at least one rotation of the second ball (10) and at least one swinging motion of the tray support in the plane of the vertical linear actuator, - the horizontal carriage (14) is actuated by a linear horizontal translation actuator (15) of substantially horizontal general direction rigidly fixed at at least a third point of the reference frame in order to allow a horizontal translation displacement of the horizontal carriage (14) during horizontal movement linear actuator for vertical translation (13).

2. Stimulator according to claim 1, characterized in that a third lever arm (16) perpendicular to the first lever arm (5) is fixed rigidly to the second end of the first lever arm on the opposite side and in the extension of the second lever arm (8), the free end of the third lever arm being fixed by a fourth ball (18) at a first end of a second linear roll actuator (19) disposed laterally and opposite the first linear roll actuator (1 1) with respect to the plate support (4) and whose second end is connected by a fifth ball joint (20) to a second point of the reference frame, the first lever arm, the second lever arm and the third lever arm thus having a T-shape, the first roll linear actuator and the second roll linear actuator operating complementarily to one another.

3. Stimulator according to claim 2, characterized in that the free ends of the second (8) and third (16) lever arms are curved (9) (17) at 90 ° in the general plane of said second and third lever arm so that the second (10) and fourth (18) ball joints are substantially in a plane perpendicular to the plate, comprising the axis of rotation of said plate and parallel to the first lever arm.

4. Stimulator according to claim 3, characterized in that the tray support (4), the first (5), second (8) and third (16) lever arm form a nacelle at least open on the front and the two reinforcements being disposed between the curved free ends of the second and third lever arms and the tray support.

5. Stimulator according to any one of the preceding claims, characterized in that the actuators are disengageable.

6. Stimulator according to any one of claims 1 to 4, characterized in that the actuators are lockable in a predefined position.

7. Stimulator according to any one of the preceding claims, characterized in that the kinetic changes can be selected from the yaw, roll, pitch, vertical translation and horizontal translation movements possibly in combination.

8. Stimulator according to any one of the preceding claims, characterized in that at least one rotating electrical connection is implemented between the plate and the tray support.

9. Stimulator according to any one of the preceding claims characterized in that at least one of the points of the reference frame for fixing the second end of the first and / or the optional second linear roll actuator is movable.

10. Stimulator according to any one of the preceding claims, characterized in that the second ball (10) and the optional fourth ball (18) are removable in order to be able to separate the first linear roll actuator (1 1) and the possible second linear roll actuator (19) of the free ends of their corresponding lever arms (8) (16).