Gravito-inertial motion simulation device

Abstract

Gravito-inertial motion simulation device. The invention relates to a device for simulating low-frequency and high-frequency accelerations, while maintaining a minimum mass. The device is based on a mobile platform (11) using omnidirectional wheels (13) and capable of carrying at least one user (12). The mobile platform (11) can move according to the degrees of freedom Tx, Ty, yaw on a horizontal surface. Inclined surfaces on which the mobile platform can move make it possible to obtain the degrees of freedom of roll and pitch. These inclined surfaces can be formed by ramps (18) arranged on the ground (20) or be an integral part of a fixed support base (10) having a horizontal part and an inclined part. Figure to be published with the abstract: Figure 4

Description

Title of the invention: Gravito-inertial device for motion simulation Technical field of the invention

[0001] Generally speaking, the present invention relates to devices capable of simulating the movement of a vehicle.

[0002] The present invention particularly relates to devices capable of simulating the movement of a land vehicle, such as an automobile, or of an air vehicle, such as a civil aviation device, by subjecting the user to certain transient or prolonged accelerations, while keeping him in a controlled and safe environment. State of the art

[0003] Vehicle motion simulators are generally classified according to the number of degrees of freedom they offer.

[0004] A common technique for simulating constant or gradually changing accelerations is to tilt the simulator cabin along the roll and / or pitch axes while maintaining the visual representation of a flat horizon. A fixed tilt creates the illusion of constant horizontal acceleration for a user in the cabin, due to the ambiguity between gravity and inertial force.

[0005] Hexapod or “Stewart platform” type motion simulators use 6 jacks to recreate all 6 degrees of freedom.

[0006] Hexapods are suitable for satisfactorily simulating constant or gradually changing accelerations (so-called low frequency) and of moderate intensity, typically less than 5 m / s2. Thus this type of motion simulator is prevalent in the aeronautical industry, in particular for the simulation of civil aviation devices.

[0007] However, hexapods are generally inadequate for simulating abruptly changing (so-called high-frequency) and high-intensity accelerations, such as those of a land vehicle such as a racing car.

[0008] One of the limitations of hexapods is their reduced travel on the translational degrees of freedom Tx (in English “surge”) and Ty (in English “sway”), which rarely exceeds one meter. This reduced working space makes their translational movements insufficient to simulate the high-frequency horizontal accelerations of a land vehicle, the hexapod quickly reaching its end of travel. Another limitation of hexapods is their reduced amplitude of movement along the yaw axis.

[0009] A physiological threshold prevents these high-frequency horizontal accelerations from being simulated by rotations. Colombet, Fang, Kemeny (2016) “Tilt thresholds for acceleration rendering in driving simulation” reported that excessively rapid roll or pitch rotations become detectable by the semicircular canals of the inner ear. The user struggles to interpret these high-frequency rotations as high-frequency horizontal accelerations, thus breaking the illusion.

[0010] Aware of these limitations, players in the automotive industry have created hybrid motion simulators by combining a hexapod-type motion simulator with an XY rail system, as described in document FR2677155B1. A cabin mounted on a mobile hexapod platform is thus placed on a system of orthogonal rails several meters long. The disadvantage of this system is the mass of the machinery required as well as its cost.

[0011] Known variations of this principle use a cable system to move the hexapod platform, rather than an XY rail system. However, these systems remain imposing and massive.

[0012] Some motion simulators directly integrate highly maneuverable industrial robots. EP2626848A1 relates to a helicopter motion simulator based on an omnidirectional industrial handling robot using mecanum wheels, offering the degrees of freedom Tx, Ty and yaw.

[0013] The omnidirectional wheel was originally described in 1919 in US1305535. The mecanum wheel is a type of omnidirectional wheel. The mecanum wheel was originally described in 1972 in US3876255A.

[0014] The use of a mobile platform using mecanum wheels, or more generally omnidirectional wheels, is a known device for performing free omnidirectional movement in the horizontal plane, according to the degrees of freedom Tx, Ty and yaw. This type of device is frequently used in technical fields other than motion simulation, such as for example in logistics with omnidirectional automatic guided vehicles.

[0015] In the context of motion simulation, a mobile platform using omnidirectional wheels advantageously replaces an XY rail system with a substantial saving on the mass of the machinery involved. In addition, the omnidirectional wheels allow rotation along the yaw axis of the mobile platform. A motion simulator based on this concept thus becomes a vehicle in its own right, able to operate autonomously thanks to batteries or by being supplied with energy by a cable which does not hinder its movement.

[0016] Thus, in the document EP2626848A1 mentioned above, the base of a robotic arm is secured to a mobile platform using mecanum wheels. The passenger cabin is carried by this robotic arm. Although degrees of freedom additional functions are accessible through this ingenious process, a disadvantage is the considerable increase in the mass to be moved. Another disadvantage is the upward displacement of the center of gravity of the entire device, which reduces the overall stability of this motion simulator.

[0017] An advantageous feature of a new motion simulator based on the concept of the omnidirectional wheel would be to be able to offer the degrees of freedom of roll and pitch, without however requiring a second mechanical stage on the mobile platform, which has the disadvantage of considerably increasing the mass to be moved and the power required, while moving the center of gravity upwards.

[0018] At the end of this overview of the state of the art, we can conclude that possibilities for improvements exist for a movement simulator that is at the same time light, realistic and versatile based on the mecanum wheel or more generally on the omnidirectional wheel.

[0019] Applicant has designed, implemented, tested and improved the present invention through several iterations in order to overcome the shortcomings of the state of the art and establish new advantages. Presentation of the invention

[0020] An objective of the present invention is a motion simulation device allowing the user to experience high frequency and low frequency accelerations over a wide range of intensity.

[0021] The invention comprises a mobile platform using omnidirectional wheels. This mobile platform has a space for carrying at least one user and behaves like an omnidirectional vehicle capable of moving on horizontal and inclined surfaces, as well as on the areas where these surfaces connect. All of these surfaces on which the platform can move define the workspace of the simulator.

[0022] It is understood that the term omnidirectional wheel designates all types of omnidirectional wheels, including the mecanum wheel.

[0023] To correctly reproduce abruptly changing horizontal accelerations, called high frequency, the mobile platform is capable of moving according to the degrees of freedom Tx and Ty on a horizontal surface. The mobile platform is also capable of performing rotations according to the yaw axis on a horizontal surface.

[0024] To correctly reproduce the illusion of constant or gradually changing horizontal accelerations, called low frequencies, it is sufficient for the mobile platform to engage on an inclined surface, thus increasing its inclination along the axis of roll or pitch, thus imparting this inclination to all elements carried by the platform, including the user. The user then feels the illusion of prolonged horizontal acceleration. The mobile platform is also capable of performing rotations along the yaw axis on an inclined surface.

[0025] Thus, the workspace of the motion simulator according to the invention comprises one or more inclined surfaces being arranged around a horizontal surface, all of these adjacent surfaces forming a continuous surface on which the mobile platform can move, said continuous surface having its concavity oriented upwards.

[0026] For this purpose, an object of the invention is a motion simulation device, said device comprising a fixed support base, a mobile platform having a space for embarking at least one user, several omnidirectional wheels coupled to said mobile platform, said omnidirectional wheels being in contact with said fixed support base, several motors coupled to said mobile platform, each of said motors individually driving one of said omnidirectional wheels, said device being characterized in that, said fixed support base comprises a portion having a substantially horizontal upper surface and a portion having a substantially inclined upper surface, said upper surfaces forming a continuous surface having an upwardly oriented concavity, said mobile platform being capable of moving on said continuous surface.

[0027] In one embodiment, the device further comprises a computer system capable of controlling said motors.

[0028] In another embodiment, the device further comprises a user interface device coupled to said mobile platform, said user interface device being capable of communicating with said computer system.

[0029] In another embodiment, the device further comprises a screen coupled to said mobile platform, said screen being capable of displaying a virtual environment generated by said computer system.

[0030] In another embodiment, said portion having a substantially inclined upper surface of said fixed support base (10) consists of at least one removable ramp (18) having an inclined upper surface

[0031] Advantageously, the device comprises a seat coupled to said mobile platform.

[0032] Advantageously, the device comprises a structural element coupled to the movable platform to provide support at the waist or back of a standing user.

[0033] Advantageously, the device comprises at least a partial replica of a vehicle or at least a partial replica of the control station of a vehicle coupled to said mobile platform.

[0034] Another object of the invention is a motion simulation device, said device comprising a mobile platform capable of moving on the ground, said mobile platform having a space for embarking at least one user, several omnidirectional wheels coupled to said mobile platform, said omnidirectional wheels being in contact with the ground, several motors coupled to said mobile platform, each of said motors individually driving one of said omnidirectional wheels, said device being characterized in that at least one ramp having an inclined upper surface is arranged above the ground, so as to form with a part of the ground a continuous surface having a horizontal part and an inclined part and having a concavity oriented upwards, said mobile platform being capable of moving on the whole of said continuous surface.

[0035] In one embodiment, the device further comprises a computer system capable of controlling said motors.

[0036] In another embodiment, the device further comprises a user interface device coupled to said mobile platform, said user interface device being capable of communicating with said computer system.

[0037] In another embodiment, the device further comprises a screen coupled to said mobile platform, said screen being capable of displaying a virtual environment generated by said computer system.

[0038] Advantageously, the device comprises a seat coupled to said mobile platform.

[0039] Advantageously, the device comprises a structural element coupled to the movable platform to provide support at the waist or back of a standing user.

[0040] Advantageously, the device comprises at least a partial replica of a vehicle or at least a partial replica of the control station of a vehicle coupled to said mobile platform. Description of figures

[0041] Other characteristics and advantages of the invention will appear on reading the detailed description of the non-limiting examples which follow, for the understanding of which reference will be made to the appended drawings among which:

[0042] [Fig-1] is a perspective view of an embodiment of the motion simulation device involving a fixed support base of rectangular shape having two inclined surfaces arranged on either side of a surface horizontal. The user sits in a seat coupled to the mobile platform and can interact with a simulation projected on an on-board screen using a user interface device.

[0043] [Fig.2] is a perspective view of one embodiment of a support base fixed circular base having an inclined surface, illustrated in an exaggerated manner, surrounding a horizontal surface. The upper surface of this fixed support base is thus shaped like a flat-bottomed bowl.

[0044] [Fig.3a] is a profile view illustrating the pitch inclination undergone by the mobile platform (11) when it engages on an inclined ramp perpendicular to its longitudinal axis.

[0045] [Fig.3b] is a rear view illustrating the roll inclination of the mobile platform (11) when it engages on an inclined ramp perpendicular to its transverse axis.

[0046] [Fig.4] is a perspective view illustrating an embodiment where four ramps having an inclined surface are arranged on the ground.

[0047] [Fig.5] is a view detailing a possibility of assembly between a motor and a mecanum type omnidirectional wheel.

[0048] [Fig.6] is a perspective view of an embodiment involving a base of fixed support and a user standing on the mobile platform. A structural element allows the user to be held at waist level or back level.

[0049] [Fig.7] is a perspective view of an embodiment where three ramps are arranged on the ground. A replica of a vehicle, here a motorcycle, is coupled to the mobile platform.

[0050] [Fig.8] is a perspective view illustrating an embodiment where four Users take their place on a widened mobile platform, and four inclined ramps are arranged on the ground.

[0051] [Fig.9] is a perspective view illustrating an embodiment where a replica The control station of a vehicle, here a Formula 1 car, is coupled to the mobile platform. A single mobile ramp is placed on the ground.

[0052] [Fig. 10] is a perspective view illustrating an embodiment involving a replica of an aircraft cockpit. Detailed description of the invention

[0053] Two main embodiments concern the manner in which the inclined surfaces required for the invention are implemented: either by using a fixed support base (10) having a horizontal part and an inclined part, or by using ramps (18) having an inclined upper surface, said ramps being arranged on the ground (20).

[0054] Several combinations of variants are possible in addition to the choice of the main embodiment, such as the presence of a seat (17), a screen (16), at least a partial replica of the driving position of a vehicle (101), at least a partial replica of a vehicle (100), etc.

[0055] [Fig.4] represents a first embodiment of the mobile platform (11) and ramps having an inclined surface (18) arranged on the ground (20).

[0056] In this first embodiment, a mobile platform (11) is propelled by 4 omnidirectional mecanum-type wheels (13), each being operatively connected to its own motor (14). The assembly of a motor to a mecanum wheel as well as the securing of this assembly to the chassis of the mobile platform (11) is shown in [Fig.6].

[0057] The first design decision that must be made by a person skilled in the art is the determination of the necessary motor power as a function of fundamental parameters of the motion simulator, such as the total mass to be moved and the desired maximum acceleration, this maximum acceleration depending on the type of vehicle to be simulated.

[0058] Possible mechanical reduction means (R) interposed between each motor (14) and the mecanum wheel (13) driven by this motor determine the torque transmitted to the wheel and its maximum rotational speed. These mechanical reduction means may for example include gears, a planetary type gearbox, a worm gearbox, etc. In this first embodiment, a planetary type gearbox (R) has been selected.

[0059] It is also possible to use transmission means comprising, for example, belts and pulleys, transmission shafts, cardan-type joints, etc. in order to transmit the mechanical power of each motor to the corresponding mecanum wheel. In this first embodiment, a transmission shaft (A) connects the motor (14) and planetary gearbox (R) assembly to the mecanum wheel (13).

[0060] It is possible to assemble a suspension mechanism on the mecanum wheel in order to absorb surface irregularities. No suspension mechanism was used in this first embodiment.

[0061] The engine, gearbox, shaft and mecanum wheel assembly is coupled to the rectangular chassis (C) forming the base of the mobile platform (11) by means of a rolling bearing (P) supporting the transmission shaft (A).

[0062] Each motor must be powered either by an on-board battery or directly by a cable (not shown) which will be linked to the mobile platform (11) while using means so that the cables do not hinder the movement of said mobile platform (11). In this first embodiment, cables have been chosen to power the motors (14) and are combined into a cable harness.

[0063] A rotating collector may be used to allow unlimited rotation of the mobile platform (11) without tangling the cables.

[0064] The transmission of data to the motors (14) can be carried out by wire, used in this first embodiment, or wirelessly.

[0065] The algorithm for obtaining omnidirectional movement using 4 mecanum wheels is known in the prior art.

[0066] A seat (17), a user interface device (15) such as a steering wheel and a screen (16) are secured to the chassis of the mobile platform (11). The cables providing power and data to the screen (16) are bundled with the cable harness powering the motors.

[0067] A computer system generates the display of the virtual environment of the simulation on the screen (16), taking into account the data received by the user interface device (15). This same computer system issues instructions intended for each motor (14). The user interface device (15) can also receive data from the computer system, in particular in the case of force feedback devices. Various sensors can be connected to the computer system.

[0068] Concerning the inclined surfaces involved in this first embodiment, they are implemented by ramps (18) having an inclined surface. These ramps can be for example made of rigid rubber or wood. It is important that the threshold of each ramp is sufficiently low so as not to generate jolts when the mobile platform rolls over them.

[0069] In the reference system linked to the fixed ramps (and also linked to the fixed support bases which will be used in a second embodiment), the X direction is defined with reference to the illustrations as being mainly the direction of longitudinal accelerations and the Y direction as being mainly the direction of transverse accelerations.

[0070] A longitudinal axis and a transverse axis may also be defined for the mobile platform. Rotation about the longitudinal axis of the mobile platform causes a rolling sensation for the user as positioned in the illustrations. Rotation about the transverse axis of the platform causes a pitching sensation for the user as positioned in the illustrations.

[0071] It will be agreed that the longitudinal axis of the mobile platform corresponds to its degree of freedom Tx, while the transverse axis corresponds to its degree of freedom Ty.

[0072] In the absence of a command, the control algorithm is designed to continuously correct the orientation of the mobile platform in order to make the longitudinal axis coincide of the mobile platform with the X direction and by the same, the transverse axis of the mobile platform with the Y direction.

[0073] Thus, when the computer system issues a movement command according to the yaw degree of freedom, the platform performs this rotation, but is slowly brought back towards its nominal orientation, namely in the direction of X, in the direction of positive X, by the control algorithm.

[0074] During operation of the motion simulator, the mobile platform (11) will use the horizontal surface for high frequency accelerations and will engage on an appropriate ramp (18) if an acceleration in a certain direction is prolonged in time.

[0075] The mobile platform simulates a prolonged longitudinal acceleration illustrated in [Fig.3a] by moving in the X direction and engaging on a ramp located in this direction.

[0076] The mobile platform simulates a prolonged transverse acceleration illustrated in [Fig.3b] by moving in the Y direction and engaging on a ramp located in this direction.

[0077] The upper surface of each inclined ramp may be inclined and flat or inclined and curved. The geometry of the ramps may thus be calculated to result in a certain angle of inclination depending on the position of the mobile platform on the ramp, and in particular to provide an inclination which increases in a non-linear manner as the mobile platform advances on the ramp.

[0078] During the transition phases where the mobile platform is straddling a horizontal surface and an inclined surface, the angle of inclination of the mobile platform varies as a function of the distance traveled on the inclined surface according to a certain mathematical equation involving in particular the wheelbase distance between the mecanum wheels located at the front of the mobile platform and the mecanum wheels located at the rear, if the platform moves in the X direction. If the platform moves in the Y direction, this equation involves the wheelbase between the mecanum wheels located to the left and right of the mobile platform (11).

[0079] In order for the ramps (18) to be secured to the ground, it is possible, for example, to use double-sided adhesive or permanent fixing elements.

[0080] A means for precisely locating the mobile platform (11) allows the control algorithm to know the position and orientation of said platform on its workspace covering the horizontal surface and the inclined ramps. Such a localization means may comprise an optical motion capture system, an indoor positioning system or even a system using ground markings, these examples being non-limiting.

[0081] Redundant safety systems are considered, including an emergency stop button, ultrasonic or LIDAR type sensors or even a geometry of the ramps physically blocking the movement of the mobile platform outside its workspace.

[0082] In a second embodiment, the main difference with the first embodiment is that the ramps (18) and the floor (20) are substituted by a fixed support base (10) natively integrating inclined surfaces and horizontal surfaces. This second embodiment is illustrated by figures [Fig.l], [Fig.2] and [Fig.6].

[0083] The fixed support bases (10) are intended for more intensive and permanent use of the simulator. They can be made from a single block, for example, of wood, cement or rigid rubber. They can also be formed by an assembly of removable blocks.

[0084] The other figures illustrate other embodiments corresponding in particular to various types of vehicles and uses.

[0085] [Fig.9] represents a simulation of the movement of a racing car. In this case, the acceleration phases are generally prolonged while the braking phases are brief and of high intensity. Thus, the mobile platform can engage on an inclined ramp located in the extension of the X axis and in the direction of the positive X to simulate a prolonged and moderate acceleration, and exploit the horizontal surface for a brief and intense braking. If the simulated circuit includes few prolonged turns, it may be appropriate in this scenario to use only a single ramp located in front of the mobile platform, in the extension of the X axis and in the direction of the positive X.

[0086] [Fig. 10] represents a use of the invention as a motion simulator of a civil aviation aircraft. Such an aircraft can undergo long phases of moderate acceleration and moderate deceleration, hence the presence of two ramps arranged in the extension of the X axis, both in the positive X and negative X directions. Most turns of a civil aviation aircraft are called “coordinated turns” i.e., a passenger on board does not feel the sensation of rolling when the aircraft makes such a turn. The ramps in the Y direction are thus optional. The mobile platform will thus use the horizontal surface to reproduce high frequency transverse accelerations.

[0087] [Fig.8] illustrates an embodiment suitable in particular for amusement parks, with a mobile platform capable of carrying several users, who can wear virtual reality headsets (not shown) or view an image projected onto a large curved screen (not shown). This embodiment makes it possible, among other things, to simulate a stage attraction with potentially unlimited dimensions.

[0088] [Fig.7] shows an embodiment suitable for a games room, with a replica of a motorcycle (100) or other vehicle on which or in which the user can sit, increasing the realism of the experience.

[0089] [Fig.6] represents an embodiment of the invention adapted to locomotion in virtual reality, aiming to reduce or eliminate the sensation of motion sickness which is a problem in this industry. A structural element (19) coupled to the mobile platform ensures the support of the user at the waist or back. One can consider an omnidirectional treadmill device or an equivalent, embarked by the mobile platform (11) which would complement this embodiment.

Claims

Claims

1. Motion simulation device, said device comprising - a fixed support base (10) - a mobile platform (11) having a space for embarking at least one user (12) - several omnidirectional wheels (13) coupled to said mobile platform (11), said omnidirectional wheels (13) being in contact with said fixed support base (10), - several motors (14) coupled to said mobile platform (11), each of said motors (14) individually driving one of said omnidirectional wheels (13), said device being characterized in that, - said fixed support base (10) comprises a portion having a horizontal upper surface and a portion having an inclined upper surface, said upper surfaces forming a continuous surface having an upwardly oriented concavity, said mobile platform (11) being capable of moving on said continuous surface.

2. Device according to claim 1 further comprising a computer system capable of controlling said motors (14).

3. The device of claim 2 further comprising a user interface device (15) coupled to said mobile platform (11), said user interface device (15) being capable of communicating with said computer system.

4. Device according to claim 3 further comprising a screen (16) coupled to said mobile platform (11), said screen (16) being capable of displaying a virtual environment generated by said computer system.

5. Device according to claim 1, 2, 3 or 4 further comprising a seat (17) coupled to said movable platform (11).

6. Device according to claim 1 wherein said portion having an inclined upper surface of said fixed support base (10) consists of at least one removable ramp (18) having an inclined upper surface.

7. A motion simulation device, said device comprising - a mobile platform (11) capable of moving on the ground (20), said mobile platform having a space for embarking at least one user (12) - several omnidirectional wheels (13) coupled to said mobile platform (11), said omnidirectional wheels (13) being in contact with the ground (20), - several motors (14) coupled to said mobile platform (11), each of said motors (14) individually driving one of said omnidirectional wheels (13), said device being characterized in that, - said device further comprises at least one ramp (18) having an inclined upper surface, said ramp (18) being arranged above the ground (20), so as to form with a part of the ground a continuous surface having a horizontal part and an inclined part and having a concavity oriented upwards, said mobile platform being capable of moving on the whole of said continuous surface.

8. Device according to claim 7 further comprising a computer system capable of controlling said motors (14).

9. The device of claim 8 further comprising a user interface device (15) coupled to said mobile platform (11), said user interface device (15) being capable of communicating with said computer system.

10. A device according to claim 9 further comprising a screen (16) coupled to said mobile platform (11), said screen (16) being capable of displaying a virtual environment generated by said computer system.

11. A device according to claim 7, 8, 9 or 10 further comprising a seat (17) coupled to said movable platform (11).

12. A device according to claim 1 or 7 further comprising a structural member (19) coupled to the movable platform (11) to provide support at the waist or back of a standing user.

13. Device according to claim 1 or 7 further comprising at least a partial replica of a vehicle (100) or at least a partial replica of the control station of a vehicle (101) coupled to said mobile platform.

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