Omnidirectional Wheel and Operating Method

Abstract

OMNIDIRECTIONAL WHEEL AND OPERATING METHOD A spherical omnidirectional wheel comprises a support (2) attached to a frame by a first and a second power shaft (9, 10) forming a pivot joint defining a first axis of rotation (XX). A first hemisphere (3) and a second hemisphere (4) are attached to the support (2) and are separated by a support plane passing through the support (2). A first and a second gear (5, 6) are coupled respectively to the first and second power shafts (9, 10). A third bevel gear (7) is meshed with the first and second gears (5, 6). The third gear (7) is fixed to the first hemisphere (3) and the second hemisphere (4) to rotate the first and second hemispheres (3, 4) around the first axis of rotation (XX) and around a second axis of rotation (YY).

Description

Title of the invention: Omnidirectional wheel and operating method technical field

[0001] The invention relates to an omnidirectional wheel and a method of operating such a wheel. State of the art

[0002] To facilitate the movement of many vehicles, significant research is being conducted on omnidirectional wheels, that is, wheels capable of moving in all directions parallel to the plane of the road or the surface on which the wheel travels. Many passive wheels exist that are mounted on a rotating ring so as to be able to move in all directions. This technical solution is simple to implement but is limited to passive wheels, that is, wheels that do not contribute to propelling the vehicle in any direction. An example of such an embodiment is presented in document WO2021 / 102556. Assemblies of spherical and passive wheels are proposed with offset axes of rotation to allow movement in all directions. An example of such an embodiment is presented in document CN109624607.

[0003] There are also wheels with a more or less complex shape, featuring a circular body that rotates around an axis of rotation to move forward or backward. This configuration is conventional, except for the wheel tread, which is formed by rollers whose axes of rotation are located at the periphery of the wheel and are offset to allow for right- or left-hand movement. In practice, this technical solution has proven unsatisfactory and appears dependent on the road surface condition. An example of such an embodiment is presented in US patent 8,424,621.

[0004] This wheel configuration has been modified to have a more spherical shape in order to be less dependent on the ground surface condition. An example embodiment is shown in documents CN106427390, JP2016-182912 and JP2007-210576. Complex reinforcement architectures arranged inside a spherical shell are also proposed, as illustrated in document CN 106739783.

[0005] There is considerable interest in an omnidirectional wheel with a spherical shape. However, such a configuration is difficult to drive in multiple directions in order to move right, left, forward, and backward. A technical solution has been proposed in which the wheel is in contact with several drive rollers that are rotated by motors. Depending on the motors By activating the drive rollers and determining their direction of rotation, it becomes possible to control the wheel's direction of rotation. Since the drive rollers are positioned in contact with the friction band, the wear of the friction band plays a crucial role in steering control. The same is true for the surface condition of the drive rollers. It appears that this technical solution is unsatisfactory. Description of the invention

[0006] An object of the invention consists of providing a steering wheel which is active, that is to say, which is capable of moving a vehicle and whose power delivered is better controlled to move the wheel in the chosen directions.

[0007] These drawbacks are addressed by means of a spherical omnidirectional wheel comprising: - a support intended to be attached to a frame by a pivot joint defining a first axis of rotation; - a first hemisphere intended to be covered by a first tread and attached to the support; - a second hemisphere intended to be covered by a second tread and attached to the support, the first hemisphere being separated from the second hemisphere by a support plane passing through the support and representing a median plane of the spherical omnidirectional wheel; - a first conical gear intended to be connected to a first power source preferably by a first power shaft extending along the median plane; - a second conical gear intended to be connected to a second power source preferably by a second power shaft extending along the median plane; - a third conical gear meshed with the first gear and with the second gear, the third gear being fixed to the first hemisphere and the second hemisphere to rotate the first hemisphere and the second hemisphere around the first axis of rotation included in the median plane and to rotate the first hemisphere and the second hemisphere around a second axis of rotation perpendicular to the median plane.

[0008] According to an advantageous aspect of the invention, the third gear is fixed to the first hemisphere and to the second hemisphere by a coupling shaft passing through the third gear along a diameter of the sphere.

[0009] Preferably, the first toothed wheel is connected to the first hemisphere by means of an elastically deformable coupler.

[0010] Advantageously, the first power shaft is collinear with the second power shaft and they form the pivot joint.

[0011] Preferably, a chassis is attached to the support and has a circular bearing supporting the first hemisphere and extending in a plane parallel to the median plane.

[0012] In a preferred embodiment, the first power shaft is hollow and the second power shaft is installed inside the first power shaft.

[0013] Preferably, the omnidirectional wheel comprises a first power source connected to the first gear to rotate the first gear, a second power source connected to the second gear to rotate the second gear, a control circuit connected to the first power source and the second power source to control a power delivered by each of the first and second power sources, and a measuring device equipped with at least a gyroscope and / or a plurality of accelerometers, the measuring device being disposed in a volume delimited by the first and second hemispheres and configured to provide at least one representative measurement of the displacements of the omnidirectional wheel about the first axis of rotation and about the second axis of rotation.The measuring device is connected to the control circuit, and the control circuit adjusts the power delivered by the first power source and the power delivered by the second power source according to a difference between a setpoint and at least one measurement.

[0014] The invention also relates to a vehicle capable of moving more easily in all directions while being easier to produce.

[0015] This result is tended to be achieved by means of a vehicle comprising at least one steering wheel according to any of the preceding configurations.

[0016] The invention also relates to a method of operating an omnidirectional wheel which is efficient and simple to use.

[0017] This result is to be achieved by means of a method for operating an omnidirectional wheel comprising the following steps: - provide an omnidirectional wheel according to any one of the previous configurations; - rotate at least one of the first gear and the second gear at a first rotational speed to rotate the omnidirectional gear around the first axis of rotation (XX) and / or the second axis of rotation. Description of the drawings

[0018] Other advantages and features will become clearer from the following description of particular embodiments and implementations of the invention given by way of non-limiting examples and shown in the accompanying drawings, in which:

[0019] [Fig-1] schematically illustrates a perspective view of a wheel omnidirectional according to one embodiment;

[0020] [Fig.2] schematically illustrates a perspective view of half of an omnidirectional wheel according to one embodiment, the cutting plane representing a median cut perpendicular to the support plane and perpendicular to the first axis of rotation;

[0021] [Fig.3] schematically illustrates a perspective view of a support for an omnidirectional wheel, with coupling shafts and power shafts fixed to the support;

[0022] [Fig.4] schematically illustrates a perspective view of a support for an omnidirectional wheel, coupling shafts, power shafts and part of a chassis being fixed to the support;

[0023] [Fig.5] schematically illustrates another perspective view of a support for an omnidirectional wheel, coupling shafts, power shafts and part of a chassis being fixed to the support;

[0024] [Fig.6] schematically illustrates a perspective view of a chassis mounted around a support attached to coupling shafts, power shafts;

[0025] [Fig.7] schematically illustrates a perspective view of a chassis mounted around a support attached to coupling shafts, power shafts, the coupling shafts being terminated by distal pieces of hemispheres:

[0026] [Fig.8] schematically illustrates a cross-sectional view of an omnidirectional wheel;

[0027] [Fig.9] schematically illustrates a perspective view of half a wheel omnidirectional with half of a chassis mounted around the power shafts, the cut being made according to a support plane;

[0028] [Fig. 10] schematically illustrates a side view of the configuration illustrated in [Fig.9];

[0029] [Fig. 11] schematically illustrates a perspective view of half of an omnidirectional wheel, the cut being made perpendicular to the support plane and perpendicular to the first axis of rotation, the second hemisphere being without a tread;

[0030] [Fig. 12] schematically illustrates a perspective view of an omnidirectional wheel lacking the first hemisphere;

[0031] [Fig. 13] schematically illustrates a perspective view of a section of an omnidirectional wheel illustrated in [Fig. 12], the section being a median section perpendicular to the support plane and perpendicular to the first axis of rotation;

[0032] [Fig. 14] schematically illustrates a perspective view of an omnidirectional wheel whose first hemisphere is devoid of an intermediate piece and a distal piece;

[0033] [Fig. 15] schematically illustrates a perspective view of a cross-section of an omnidirectional wheel shown in [Fig. 14], the cross-section being a median cross-section perpendicular to the support plane and perpendicular to the first axis of rotation

[0034] [Fig. 16] schematically illustrates a perspective view of an omnidirectional wheel whose first hemisphere lacks a distal part;

[0035] [Fig. 17] schematically illustrates a perspective view of a section of an omnidirectional wheel illustrated in [Fig. 16], the section being a median section perpendicular to the support plane and perpendicular to the first axis of rotation;

[0036] [Fig. 18] schematically illustrates a perspective view of an omnidirectional wheel whose first hemisphere is devoid of a tread;

[0037] [Fig. 19] schematically illustrates another embodiment of an omnidirectional wheel equipped with two motors arranged in the chassis;

[0038] [Fig.20] schematically illustrates an omnidirectional wheel mounted on a vehicle frame. Detailed description

[0039] Figures 1 to 20 illustrate different views and embodiments of an omnidirectional wheel 1 and a vehicle equipped with such a wheel. The omnidirectional wheel 1 is a spherical omnidirectional wheel, that is, it has a spherical or substantially spherical external shape. The omnidirectional wheel 1 is an active wheel, that is, it is designed to connect to one or more motors, to one or more shafts that deliver power to drive the omnidirectional wheel 1 in rotation, or to any other means capable of delivering power, for example, electrical or hydraulic power.

[0040] The omnidirectional wheel 1 has a support 2. The support 2 is an element to which the other components are attached to form the omnidirectional wheel 1. The support 2 is intended to be attached to the vehicle. The support 2 is attached to the vehicle by means of a pivot joint to allow the support 2 to rotate relative to the vehicle around a first axis of rotation XX. The first axis of rotation XX is a first axis of rotation of the omnidirectional wheel 1 relative to the vehicle for moving the vehicle.

[0041] The omnidirectional wheel 1 has a shell that is preferably substantially spherical in shape. The shell is formed, for example, by a first hemisphere 3 and a second hemisphere 4. The first hemisphere 3 and the second hemisphere 4, together with the support 2, form an external shell that is preferably spherical. Since the omnidirectional wheel 1 receives power from outside the shell to supply drive means located inside the shell, a purely spherical shape is not possible.

[0042] The periphery of the shell has, or is adapted to receive, treads, for example, a first tread 3a and a second tread 4a whose external faces have a hemispherical shape to be compatible with the rotation of the omnidirectional wheel 1. The first hemisphere 3 and second hemisphere 4 may each be made in a single piece, but it is also possible that they may be made of several pieces assembled together before being assembled to the support 2, or each assembled to the support 2 independently of the others. The treads may be smooth or they may have patterns. The first hemisphere 3 and / or the second hemisphere 4 may have any shape which is compensated for by the associated tread to obtain an omnidirectional wheel of generally spherical shape.

[0043] The omnidirectional wheel 1 may have one or two anchor points to define the pivot joint between the omnidirectional wheel 1 and the rest of the vehicle. The support 2 is substantially stationary relative to the anchor point. The support 2 is traversed by the first axis of rotation XX and rotates about the first axis of rotation XX.

[0044] The first hemisphere 3 and the second hemisphere 4 are attached to the support 2 to form a rigid assembly capable of defining a shell suitable for supporting a vehicle. The first hemisphere 3 and the second hemisphere 4 are mounted to rotate relative to the support 2 to allow rotation of the hemispheres about the support 2. The first hemisphere 3 and the second hemisphere 4 are mounted to rotate about a second axis of rotation YY which is perpendicular to the first axis of rotation XX in order to move the vehicle supported by the steering wheel 1. The second axis of rotation YY passes through the support 2.

[0045] The mobility of the shell in rotation around the first axis of rotation XX and around the second axis of rotation YY and independently of each other allows a displacement of the omnidirectional wheel 1 in all directions parallel to the ground supporting the omnidirectional wheel 1.

[0046] The first hemisphere 3 and the second hemisphere 4 are separated by a support plane that passes through the support 2 and contains the first axis of rotation XX. The first hemisphere 3 and the second hemisphere 4 are each mounted at rotation with respect to the second axis of rotation YY which is perpendicular to a support plane. The support plane is preferably a median plane of the omnidirectional wheel 1 which contains the first axis of rotation XX.

[0047] Each of the first axis of rotation XX and the second axis of rotation YY extends along a diameter of the omnidirectional wheel 1 represented by a sphere.

[0048] The omnidirectional wheel 1 has at least one first gear 5, one second gear 6, and one third gear 7. Each of the first gear 5, the second gear 6, and the third gear 7 is a bevel gear. Each gear is preferably in the form of a truncated cone. The bevel gear is well known to those skilled in the art.

[0049] The first gear 5 and the second gear 6 are each meshed with the third gear 7. The first gear 5 and the second gear 6 are not directly meshed with each other. Preferably, the first gear 5 and the second gear 6 are identical and mesh with the same teeth of the third gear 7.

[0050] The axis of rotation of the first gear 5 and the axis of rotation of the second gear 6 are collinear and preferentially define the first axis of rotation XX. The axis of rotation of the first gear 5 and the axis of rotation of the second gear 6 are preferably mounted fixed relative to the support 2, that is to say they can rotate on themselves but they are always in the same place with respect to the support 2 and with respect to the anchoring point with the vehicle.

[0051] The third gear 7 is meshed with the first gear 5 and with the second gear 6 and it can move around the axis of rotation of the first gear 5 and the second gear 6. The speed of movement around the first axis of rotation XX is defined by the difference in speed of rotation which exists between the speed of the first gear 5 and the speed of the second gear 6.

[0052] The first gear 5 and the second gear 6 are free to rotate at the same or different speeds and in the same or different directions of rotation in order to define the speed of movement of the omnidirectional wheel 1 parallel to the first axis of rotation XX and parallel to the second axis of rotation YY.

[0053] Preferably, the first gear 5 and the second gear 6 are fixed in a fixed manner to the support 2, that is to say that they can each rotate on themselves, but that they each have a fixed position with respect to the support 2.

[0054] The rotation of the third gear 7 around the first axis of rotation XX causes the first hemisphere 3 and the second hemisphere 4 to rotate around the first axis of rotation XX. The rotation of the third gear 7 around The second axis of rotation YY causes the first hemisphere 3 and the second hemisphere 4 to rotate around the second axis of rotation YY. In other words, the displacement of the third gear 7 relative to the vehicle causes the omnidirectional gear 1 to rotate with a component about the first axis of rotation XX and / or about the second axis of rotation YY.

[0055] The third gear 7 can be directly attached to the first hemisphere 3 and directly attached to the second hemisphere 4. The first hemisphere 3 can be directly attached to the second hemisphere 4, and the third gear 7 is directly attached to one of the hemispheres. The rotation of the first hemisphere 3 causes the rotation of the second hemisphere 4, and vice versa.

[0056] Alternatively, at least one flexible link is arranged between the first hemisphere 3 and the second hemisphere 4. The flexible link makes it possible not to apply too much torque during a start or during braking.

[0057] In the particular embodiment illustrated in [Fig. 2], the first hemisphere 3 and the second hemisphere 4 are attached to each other by a coupling shaft 8. The coupling shaft 8 extends in a direction collinear with the second axis of rotation YY. It is advantageous to install a coupler 8a made of polymer material, for example elastomer, which will deform during the intense acceleration and deceleration phases.

[0058] The coupling shaft 8 is functionally fixed to the third gear 7. The movements of the third gear 7 relative to the support 2 cause the shell to rotate in the same direction. It is advantageous for the coupling shaft 8 to be fixedly mounted to the third gear 7 so that each of the movements of the third gear 7 is transmitted to the first hemisphere 3 and to the second hemisphere 4.

[0059] When the first gear 5 and the second gear 6 rotate in the same direction and at the same speed, the third gear 7 is stationary relative to the first gear 5 and the second gear 6. The third gear 7 rotates about the first axis of rotation XX at the same rotational speed as the first gear 5 and the second gear 6. The first hemisphere 3 and the second hemisphere 4 rotate about the first axis of rotation XX, driving the support 2. It has no rotational component about the second axis of rotation YY. The coupling shaft 8 rotates about the first axis of rotation XX.

[0060] When the first gear 5 and the second gear 6 rotate in opposite directions and at the same speed, the third gear 7 is stationary relative to the first axis of rotation XX and rotates about itself about the second axis of rotation YY. The first hemisphere 3 and the second hemisphere 4 rotate about the second axis of rotation YY without driving the support 2, which is fixed by relation to the vehicle. It has no rotational component around the first axis of rotation XX. The coupling shaft 8 rotates around the second axis of rotation YY.

[0061] In the absence of rotation of the first gear 5 and the second gear 6, there is no rotation of the omnidirectional gear 1.

[0062] When at least one of the first gear 5 and the second gear 6 rotate, and in a configuration different from the previous cases, the third gear 7 rotates about the first axis of rotation XX and about the second axis of rotation YY, which causes the omnidirectional gear 1 to rotate with a component about the first axis of rotation XX and about the second axis of rotation YY. The second axis of rotation YY rotates about the first axis of rotation XX, taking the vehicle as its reference frame.

[0063] When the first gear 5 and the second gear 6 rotate at different speeds in the same direction or in opposite directions, there is a combination of rotation about the first axis of rotation and rotation about the second axis of rotation. Modulating the speeds and directions of rotation allows us to define whether the omnidirectional gear 1 should exhibit pure rotation about the first axis of rotation XX and its direction of rotation, pure rotation about the second axis of rotation YY and its direction of rotation, or a combination of these two rotations and their respective directions of rotation.

[0064] In the embodiment illustrated in [Fig. 3], the first gear 5 is connected to a first power shaft 9 which passes through the support 2 and is intended to couple to a first power source, for example, a motor. The motor may be a heat engine, a hydraulic motor, an electric motor, or of another technology. The rotation of the first power shaft 9 causes the rotation of the first gear 5.

[0065] In the embodiment illustrated in [Fig. 3], the second gear 6 is connected to a second power shaft 10 which passes through the support 2 and is intended to couple to a second power source, for example, a motor. The motor may be a heat engine, a hydraulic motor, an electric motor, or of another technology. The rotation of the second power shaft 10 causes the rotation of the second gear 6.

[0066] The rotation of the first power shaft 9 is independent of the rotation of the second power shaft 10. This embodiment is particularly advantageous because the omnidirectional wheel 1 is simple to implement and has a limited number of parts, which reduces the risk of failure. This also reduces the weight of the omnidirectional wheel 1, which is advantageous for a rolling element, especially one that rolls at high speed. Maintenance interventions inside the omnidirectional wheel 1 are limited to wear of the gears. The first power shaft 9 and the second power shaft 10 preferentially define the axis of rotation of the support 2 relative to the vehicle for the pivot joint and even more preferentially the first axis of rotation XX.

[0067] It is conceivable to have a fourth gear (not illustrated). It is advantageous for the fourth gear to be mounted freely and not fixed directly to either of the first hemisphere 3 and the second hemisphere 4. It is preferable for the fourth gear to be conical.

[0068] According to the embodiment, the first motor can be installed within a volume defined by the first hemisphere 3 and the second hemisphere 4 or outside the volume defined by the first hemisphere 3 and the second hemisphere 4. [Fig. 4] illustrates an embodiment where the motors are arranged outside the omnidirectional wheel 1, while [Fig. 19] illustrates a substantially identical configuration where the motors are arranged inside the omnidirectional wheel 1, i.e., inside the volume delimited by the first hemisphere 3 and the second hemisphere 4. In the embodiment of [Fig. 4], the first power shaft 9 and the second power shaft 10 are rotatably mounted and are mounted in a bearing 15 which connects to the frame 11.The bearing 15 can be a ball bearing, a bearing or any other equivalent means which allows rotation of the first hemisphere 3 and the second hemisphere 4 around the first axis of rotation XX.

[0069] In the embodiment of [Fig. 19], the bearing 15 is replaced by a motor 16 which is fixed on one side to an anchor shaft that is permanently mounted to the vehicle and which is fixed on the other side to the first or second bevel gear. The first power shaft 9 and the second power shaft 10 serve as anchor shafts for the omnidirectional gear 1. The ends of the first power shaft 9 and the second power shaft 10 define the first axis of rotation XX for the omnidirectional gear 1.

[0070] As illustrated in [Fig. 20], when the first motor is installed outside the volume delimited by the first hemisphere 3 and the second hemisphere 4. The first motor is fixed to the vehicle and is connected to the first gear 5 by means of the first power shaft 9. The motor can be of any technology; the power delivered to the first gear 5 is transmitted by the first power shaft 9. The same can be true for the second gear 6 connected to a second motor by the second power shaft.

[0071] In an alternative embodiment illustrated in [Fig. 19], the first motor 16 is installed in the omnidirectional wheel 1. The omnidirectional wheel 1 is attached to the vehicle by at least one anchor point and preferably two anchor points which define the first axis of rotation XX. It is advantageous to use rods or shafts to form the anchor points that allow the omnidirectional wheel 1 to rotate around the first axis of rotation XX. When the first motor 16 is an electric motor, an electrical connection can link the first motor 16 to an electrical power source. When the first motor is a hydraulic motor, a hydraulic connection can link the first motor to a hydraulic power source. The same can be true for other motor technologies. Power is transmitted through the shaft forming the anchor point, which is preferably hollow. It is also possible to supply power using a contactless technology, for example, by electrical induction, but the power delivered is much lower, making it a suitable solution for harsh environments and where the rotational speed is low due to the weight of the components integrated inside the casing.

[0072] An identical assembly is applied for a second motor fixed to a second attachment point and coupled to the second toothed wheel 6.

[0073] The first gear 5 and the second gear 6 can be coupled to motors having different technologies in order to improve the compromise between the compactness of the omnidirectional wheel 1. One of the two gears can be coupled to a power shaft and the other of the gears is coupled to a motor disposed in the hull.

[0074] For example, the first gear 5 is attached to a wheel-motor type motor, the other end of which is attached to the anchor shaft. The same can be true for the second gear 6, which has another wheel-motor attached to its other end and is attached to another anchor shaft.

[0075] Depending on power requirements, space constraints and the type of power used, rotation speeds, the inside of the hull can be equipped with one motor, two motors or no motor.

[0076] In the embodiment illustrated in [Fig. 3], the support 2 is attached to the vehicle by means of a first power shaft 9 and a second power shaft 10 extending in two collinear directions representing the first axis of rotation XX. This embodiment is advantageous because it allows for secure attachment of the support 2 to the vehicle. Alternatively, the first power shaft 9 is hollow and is traversed by the second power shaft 10. In another alternative, the first power shaft 9 is hollow and is traversed by an electrical, hydraulic, pneumatic, or other connection connected to a motor coupled to the second gear 6. It is advantageous to have an additional anchor point to the vehicle on the other side of the omnidirectional gear 1 to ensure secure attachment to the vehicle.

[0077] In a particularly advantageous manner, a chassis 11 is fixedly mounted to the support 2. The chassis 11 has an outer wall that defines a circular surface in a cutting plane parallel to the support plane. A circular bearing 12 is disposed on the circular surface of the frame 11, and the first hemisphere 3 has an inner wall with a shape complementary to the circular bearing 12. With this configuration, part of the forces applied to the first hemisphere 3 are absorbed by the frame 11 and by the support 2 attached to the anchor points. Advantageously, the same is true for the second hemisphere 4 in the other part of the frame 11.

[0078] Figure 20 illustrates a partial view of a vehicle which is equipped with a wheel Omnidirectional wheel 1. The vehicle is equipped with a frame, for example with suspension. A first motor is located outside the omnidirectional wheel 1 and is coupled to a first power shaft 9 to rotate the first power shaft 9 around its axis of rotation, which forms the first axis of rotation XX of the omnidirectional wheel 1. The first power shaft 9 is coupled to the first gear 5. In the illustrated example, the coupling is achieved by means of a wall. In the illustrated example, the first motor and the omnidirectional wheel 1 are located on the same side of the suspension so that they move identically relative to the rest of the frame. The second gear 6 can be rotated by means of a second motor (not shown) located in a substantially identical position on the other side of the omnidirectional wheel 1, using the other shaft of rotation as a second power shaft 10.It is advantageous for the vehicle to have at least one omnidirectional wheel, for example a vehicle with a single front or rear wheel. It is more advantageous for the vehicle to have at least two omnidirectional wheels and preferably for all wheels to be omnidirectional.

[0079] In a particular embodiment illustrated in Figures 3, 4, 5, and 6, the support 2 is surmounted by a chassis 11 which is fixedly mounted to the support 2. Rotation of the support 2 about the first axis of rotation XX causes rotation of the chassis 11 about the same axis. The chassis 11 defines at least one opening for attachment to the vehicle. In the illustrated embodiments, the chassis 11 defines two openings for the passage of the first power shaft 9 and the second power shaft 10.

[0080] As illustrated in Figures 4 to 6, the frame 11 is formed by a first flange 11' and a second flange 11”. It is advantageous for the first flange 11' to be fixedly attached to the second flange 11” so that the first and second flanges 11’ form a single unit. The flanges can be attached by any suitable means and preferably by screws or bolts.

[0081] It is advantageous that the two flanges define a housing for a first bearing 15 and a second bearing 15 which respectively receive the first power shaft 9 and the second power shaft 10. The bearings can be ball bearings, bushings or other devices which facilitate the rotation of the power shafts relative to the frame 11 while achieving a load transfer.

[0082] To improve the load transfer between the frame 11 and the support 2, it is advantageous to attach one or more rods 14 to the support 2. The rod(s) 14 extend in directions distinct from the first axis of rotation XX and preferably in directions intersecting the plane containing the first axis of rotation XX and the second axis of rotation YY. The embodiments illustrate a configuration where the rods 14 extend perpendicularly to the plane.

[0083] Preferably, the rods 14 terminate with fixing elements 14a which are advantageously fixed to the rods 14 in order to hang the chassis 11. The fixing elements 14a allow the position of the chassis 11 relative to the support 2 to be adjusted in order to place the intersection of the first axis of rotation XX and the second axis of rotation YY at the center of the sphere.

[0084] Preferably, the first hemisphere 3 and / or the second hemisphere 4 are made in several parts. Figures 7 and 8 illustrate the first hemisphere 3 and the second hemisphere 4, each made in two parts, with a proximal part 13', an intermediate part 13" and a distal part 13'". The proximal part 13' is closer to the support plane than the intermediate part 13" and the distal part 13'". The intermediate part 13" is closer to the support plane than the distal part 13'". It is advantageous for the proximal part 13' to be fixed directly to the intermediate part 13" and for the distal part 13'" to be fixed directly to the intermediate part 13".

[0085] The distal piece 13" is hooked to the coupling shaft 8 in order to follow the rotations of the coupling shaft 8.

[0086] In a preferred embodiment, a measuring device is disposed within the volume delimited by the first hemisphere 3 and the second hemisphere 4 in order to calculate the various rotational components of the omnidirectional wheel 1, and in particular the displacements along the first axis of rotation XX and the displacements along the second axis of rotation YY. The measuring device may be equipped with one or more linear accelerometers, preferably one or more 3-axis accelerometers. Alternatively or in addition, the measuring device may be equipped with one or more angular accelerometers, preferably one or more 3-axis accelerometers. Alternatively or in addition, the measuring device may be equipped with one or more gyroscopes. The measuring device is connected to a control circuit. which is itself connected to the power sources that rotate the first gear 5 and the second gear 6.

[0087] Installing the measuring device in the omnidirectional wheel 1 allows the rotations of the omnidirectional wheel 1 to be tracked. This makes it possible to detect any displacement that deviates from the setpoint, for example, a change in the friction force with the ground. When the user wishes to move the omnidirectional wheel in a direction that includes at least one component along the first axis of rotation XX and / or along the second axis of rotation YY, the control circuit defines the direction and speed of rotation to be applied to the first gear 5, as well as the direction and speed of rotation to be applied to the second gear 6. The measuring circuit is configured to measure the displacements of the omnidirectional wheel 1 and to send at least one piece of information representative of the displacements of the omnidirectional wheel 1 to the control circuit.When the control circuit detects that the omnidirectional wheel 1 is moving in a direction that deviates from the desired direction, it can modify the instructions applied to the first gear 5 and / or the second gear 6 so that the omnidirectional wheel 1 moves along a path that is closer to the desired path.

[0088] The measurements from the measuring device are provided to the control circuit, which is configured to control the first and second power sources, for example, the first and second motors. Based on the measurements provided by the measuring device, the control circuit can modify the speeds and / or directions of rotation of at least one of the first and second motors to approximate the desired torque between the displacement along the first axis of rotation XX and the displacement along the second axis of rotation YY.

[0089] The change in friction force may result from progressive wear of the tread and / or a localized change in the floor covering.

Claims

Demands

1. Spherical omnidirectional wheel comprising: - a support (2) intended to be attached to a frame by a pivot joint defining a first axis of rotation (XX); - a first hemisphere (3) intended to be covered by a first tread (3a) and attached to the support (2); - a second hemisphere (4) intended to be covered by a second tread (4a) and attached to the support (2), the first hemisphere (3) being separated from the second hemisphere (4) by a support plane passing through the support (2) and representing a median plane of the spherical omnidirectional wheel (1); - a first conical gear (5) intended to be connected to a first power source preferably by a first power shaft (9) extending along the median plane;- a second conical gear (6) intended to be connected to a second power source preferably by a second power shaft (10) extending along the median plane; - a third conical gear (7) meshed with the first gear (5) and with the second gear (6), the third gear (7) being fixed to the first hemisphere (3) and to the second hemisphere (4) to rotate the first hemisphere (3) and the second hemisphere (4) around the first axis of rotation (XX) included in the median plane and to rotate the first hemisphere (3) and the second hemisphere (4) around a second axis of rotation (YY) perpendicular to the median plane.

2. Omnidirectional wheel (1) according to claim 1 in which the third toothed wheel (7) is fixed to the first hemisphere (3) and to the second hemisphere (4) by a coupling shaft (8) passing through the third toothed wheel (7) along a diameter of the sphere.

3. Omnidirectional wheel (1) according to claim 2 in which the first toothed wheel (5) is connected to the first hemisphere (3) by means of an elastically deformable coupler (8a).

4. Omnidirectional wheel (1) according to any one of claims 1 to 3 wherein the first power shaft (9) is collinear with the second power shaft (10) and form the pivot joint.

5. Omnidirectional wheel (1) according to any one of claims 1 to 4 in which a chassis (11) is attached to the support (2) and has a circular bearing (12) supporting the first hemisphere (3) and extending in a plane parallel to the median plane.

6. Omnidirectional wheel (1) according to any one of claims 2 to 5 wherein the first power shaft (9) is hollow and the second power shaft (10) is installed inside the first power shaft (9) and comprising a fourth conical gear.

7. Omnidirectional wheel (1) according to any one of claims 1 to 6 comprising a first power source connected to the first gear (5) to rotate the first gear (5), a second power source connected to the second gear (6) to rotate the second gear (6), a control circuit connected to the first power source and the second power source to control power delivered by each of the first and second power sources, and a measuring device equipped with at least one gyroscope and / or a plurality of accelerometers, the measuring device being disposed in a volume delimited by the first hemisphere (3) and the second hemisphere (4) and configured to provide at least one representative measurement of the displacements of the omnidirectional wheel (1) about the first axis of rotation (XX) and about the second axis of rotation (YY),the measuring device being connected to the control circuit and the control circuit adjusting the power delivered by the first power source and the power delivered by the second power source according to a difference between a setpoint and said at least one measurement.

8. Vehicle comprising at least one omnidirectional wheel (1) according to any one of the preceding claims.

9. A method for operating an omnidirectional wheel (1) comprising the following steps: - providing an omnidirectional wheel (1) according to any one of claims 1 to 7; - rotating at least one of the first gear (5) and the second gear (6) with a first rotational speed for rotate the omnidirectional wheel (1) around the first axis of rotation (XX) and / or the second axis of rotation (YY).