Driving simulator

Abstract

The invention relates to a displacement device (2) comprising a support surface (16), a central axis (11) extending transversely to the support surface, and three arms (3, 4, 5) that are each with a central end rotatably connected to the central axis (11). A circumferential end (13, 14, 15) of the arms is movably supported on the support surface (16). Each arm supports a radial displacement member (31, 32, 33) that is movable along the respective arm in a radial direction, the displacement members being fixedly connected to a mounting frame (30). An actuator (22, 23, 24, 75,120-125) rotates the arms around the central axis so that the displacement members (31, 32, 33) are moved along the respective arms and the mounting frame is moved.

Description

[0001] Title: Driving Simulator

[0002] Technical Field

[0003] The disclosure relates a displacement device for translational movements of an object in a plane and rotational movement around an axis that is perpendicular to the plane. The disclosure furthermore relates to an actuator for use in a displacement device and to a method of positioning an object in a plane.

[0004] Background Art

[0005] Traditional Vehicle Driving Simulators (VDS) are based on flight simulators, using hexapod structures with 6 Degree of Freedom (6-DOF) motion systems. An example is the Ferrari Formula 1 "Spider” simulator. These simulators require a tall simulator building, have limited longitudinal and lateral movement, too much pitch, roll and vertical stroke, and due to long stroke actuators, a limited bandwidth.

[0006] Another drawback of a large hexapod structure is that an angle or excursion in one DOF precludes a large excursion or angle in another DOF.

[0007] The trend in VDS's is to separate the long stroke movements, longitudinal, lateral and yaw from the short stroke movements, heave, pitch, and roll.

[0008] Driving simulator platforms are known for surge and sway motions, having a large motion envelope. A known platform comprises perpendicular tracks supporting wheel-based carriages. The tracks and the carriages are driven by electromotors. A hexapod is mounted on the X-Y system and the total system can be equipped with a turntable below or above the hexapod to provide additional yaw, without negatively affecting other excursions of the hexapod. Because the known X-Y system is statically overdetermined, it requires a large structure to be assembled at great precision to prevent force fight and premature failure of bearings, for example, the rails that are mounted on the building floor need to be parallel within a tolerance of a fraction of a millimeter.

[0009] In a milling machine a very high production accuracy is by definition required so an overdetermined positioning mechanism does not add significantly to the cost. In a simulator, however, milling machine precision is not required for positioning accuracy. The position of the simulator cabin is relatively unimportant and is not perceived by the pilot / driver.

[0010] Of great importance in a driving simulator, is that the motion system shall not generate audible noise, or acceleration noise that is above a perceptible threshold. It shall only generate vibration of the actual vehicle that is part of the setpoint signal that drives the motion system. The mechanism of the motion system shall also not contribute with unwanted vibrations. A motion system that is not overdetermined is the best option to combine low cost, long life and low acceleration and audible noise.

[0011] WO 2019 / 211474 discloses a driving simulator with a fixed base platform having a flat support surface. A mobile platform is supported on the surface via air bearings and hold down magnets. The platform can be translated in X and Y directions and can be rotated around a vertical Z-axis by means of cables that are wound around the circular circumference of the platform. Each cable is coupled to an actuator, such as a winch, which are driven in mutual relation to displace the platform across the support surface and to rotate the platform around the Z-axis, while keeping a desired tension on the drive cables. On top of the mobile platform, a hexapod structure is placed for displacement in three other degrees of freedom (pitch, roll and heave) and for providing the high frequency content in X, Y and Yaw. An alternative for the above system, with similar characteristics is described in WO 2020 / 216476.

[0012] Each of the two above movement systems use the hexapod for limited pitch and roll angles, vertical movements, and generally all high frequent movements, either road-roughness, or in case of racing cars, the very fast responses to driver steering inputs. In both systems the lower system significantly augments the longitudinal and lateral stroke and the yaw capacity of the hexapod, but there is no infinite yaw capability. An infinite yaw capability can be useful for slow "washout" below driver perception level of an initial yaw input.

[0013] A lateral, longitudinal or yaw setpoint signal is usually filtered whereby the lower system executes the large stroke, low frequency content, and the hexapod system executes the short stroke high frequency content.

[0014] An alternative for the system according to WO 2020 / 216476 that features infinite yaw capability is depicted in WO 2020 / 249262.

[0015] Each of the three above systems have significant drawbacks, however. The design of WO 2019 / 211474 requires an expensive precision machined floor, expensive air bearings and "hold down" magnets.

[0016] Each of the two designs described in WO2020 / 249262 and WO 2020 / 216476 have the lower platform (base) of the hexapod cantilevered outside the center of the ground frame when in extreme X or Y excursions, which may significantly reduce the high frequency performance.

[0017] The system according to WO 2020 / 216476 is depicted in figure 7 in full surge (longitudinal) backwards position. The two rearward supports between the floor mounted guiding rails and the hexapod lower frame are too close laterally to provide a rigid foundation for the hexapod lower frame, especially affecting the rigidity against roll movements of the cockpit.

[0018] The system according to WO 2020 / 249262 is depicted in figure 5 in full surge backwards position, in which position the hexapod base frame is cantilevered outside the floor-frame center. The two most rearward actuators of the hexapod are not well supported, especially affecting the rigidity against heave movements of the cockpit.

[0019] It is an object to provide a compact displacement device, in particular a driving simulator, with a limited elevation, which is of simple construction, which does not require precision machining or alignment of large components and that has a longitudinal, a lateral and a yaw Degree of Freedom (DOF). It is an object to provide a displacement device that may be equipped with a hexapod or equivalent system, and that does not have the problems of the prior art solutions as here described. It is furthermore an object to provide a system that can also provide infinite yaw.

[0020] Summary

[0021] Hereto a displacement device according to the disclosure comprises: a support surface, a central axis extending perpendicularly to the support surface, and three arm members that are each connected with their central ends to be rotatable around a proximal axis that is situated on or near the central axis, and with a circumferential end movably supported on the support surface, each arm member supporting a radial displacement member that is movable along the respective arm in a radial direction, the displacement members being rotatably connected to a mounting frame and actuators that are adapted for rotating the arms around the central axis so that the displacement members can move radially along the respective arms whereby the mounting frame is moved.

[0022] By rotation of the arms through a setpoint angle, the mounting frame can rapidly and accurately be moved in the x-y directions across the support surface. Rotation of the arms causes radial translation of the displacement members along the arms and translation and / or yaw of the mounting frame. The invention results in a simple construction and easy and robust control of yaw and X-Y displacement with a large motion envelope and without noise and wear that is typical of an overdetermined mechanism.

[0023] The arms may with their central ends be connected to respective hubs and pivotable about a proximal axis that is at a distance from the central axis. The arms may also be connected to a central hub with their proximal axis situated on the central axis to be rotatable around the central axis.

[0024] For rapid and accurate positioning, each arm may be driven by a respective actuator, for instance a straight line or circular shaped linear motor.

[0025] The displacement device according to the disclosure may comprise a vehicle driving simulator with a movement mechanism having 1-6 degrees of freedom, such as a hexapod mechanism, connected to the mounting frame and a driver cabin supported on the movement mechanism. The large displacement envelope and low levels of unwanted noise and vibration that are transmitted to the cabin, provide an accurate simulation of a wide variety of driving conditions.

[0026] In a simulator application, a visual screen may be mounted on top of the hexapod, moving in conjunction with the vehicle cockpit. The visual screen may also be installed on the support surface (a fixed screen) or may be mounted to the triangular mounting frame (semi moving screen).

[0027] In an embodiment, each arm comprises a tangential damping member projecting from the arm in a tangential direction, so that upon rotation of the arms around the central axis, the damping members of adjacent arms abut when a predetermined minimum angle is included between the adjacent arms.

[0028] During regular operation, the damping members will not contact but they prevent damage to the displacement system when, under error conditions, the distance between neighboring arms exceeds a safety threshold.

[0029] The predetermined minimum angle between two arms is equal to the enclosed angle by the two damping members on one arm and may be between 60 and 100 degrees, preferably between 70 and 90 degrees, most preferably about 80 degrees. The system geometry is completely defined by this angle and the radius of the triangular mounting frame, on which the bearings are located which determines the scale of the displacement device.

[0030] The radial displacement member may comprise a carriage that is slidably connected to rails extending in a length direction of the arms.

[0031] The carriage can support the triangular mounting frame via a bearing, the cross-section of which in a plane of the central axis, has a curved surface, the bearing taking up forces in a direction of the central axis, as well as tangential forces.

[0032] The bearing accommodates misalignments due to unevenness of the support surface on which the circumferential end of the arms is supported. The arms may at their circumferential ends be supported by wheels running on the support surface and having a wheel axis that extends in the direction of the central axis.

[0033] Alternatively, other support means like air bearings, or a curved linear guiding are possible.

[0034] Each arm may comprise near its circumferential end a transverse beam supporting a wheel on each end. This provides a stiff support of the arms and allows for an accurately defined rotation of the arms around the central axis.

[0035] Each arm can be connected to an actuator comprising a sliding member that is movable along a support member, the sliding member being attached to a circumferential end of a respective arm via a pivoting push-pull rod.

[0036] The support member may be a linear support or may be of circular shape and concentric with the central axis. The actuator may be hydraulic, pneumatic, or electrical.

[0037] In an embodiment, the actuator comprises a linear motor with the sliding member having electrical windings and the support member comprising permanent magnets. The linear motor provides a responsive and accurate displacement of the arms.

[0038] In an embodiment the actuator comprises at least one motor drive connected to a wheel for driving the wheel in rotation. One or more wheels can be connected to an electric motor that drives the wheel axis and that is rotated with the arms around the central axis. Each arm may near its circumferential end be provided with a downward force member exerting a downward force on the arm. The downward force member may be formed by an electromagnet, providing a downward force when being magnetically attracted, provided that the support surface comprises a steel annular plate or curved beam.

[0039] An actuator for use in a displacement device comprises two spaced apart L- shaped members having support flanges and mutually opposed transverse flanges carrying multiple permanent magnets, a generally U-shaped carrier being with side parts slidably supported on the support flanges and extending over the opposed transverse flanges, coil windings being supported by a central part of the carrier between the permanent magnets. The actuator can be easily produced at relatively low costs.

[0040] A method of positioning an object in a plane comprises determining the object’s coordinates in a target position in the plane and rotating each arm through an angle around the central axis corresponding to the target position. A computer can with a simple control algorithm drive the actuators to provide a setpoint angular position to each arm. This brings the carriages on the arms each to a corresponding radial position and translates and / or rotates the carrier frame to its desired position. A transformation algorithm transforms desired X, Y and Yaw to three arm rotation setpoints.

[0041] Brief Description of The Drawings

[0042] Some embodiments of a displacement device according to the invention will, by way of non-limiting example, be described in detail with reference to the accompanying drawings. In the drawings:

[0043] Fig. 1 shows a perspective view of a displacement device, in particular a driving simulator according to the disclosure, in a central position,

[0044] Fig. 2 shows the displacement device of fig. 1 in a plan view, Fig. 3 shows a cross-sectional view of a carriage supporting a triangular frame,

[0045] Fig. 4 shows a perspective view of the displacement device of fig. 1 in a forward end position on the Y-axis,

[0046] Fig. 5 shows a plan view of the displacement device of fig.4,

[0047] Fig. 6 shows a perspective view of the displacement device of fig.l in a rearward end position on the Y-axis,

[0048] Fig. 7 shows a plan view of the displacement device of fig. 6,

[0049] Fig. 8 shows a perspective view of the displacement device of fig. 1 in a left side end position on the X-axis,

[0050] Fig. 9 shows a plan view of the displacement device of fig. 8,

[0051] Fig. 10 shows a perspective view of the displacement device of fig. 1 in a right-side end position on the X-axis,

[0052] Fig. 11 shows a plan view of the displacement device of fig. 10,

[0053] Fig. 12 shows a perspective view of the displacement device of fig. 1 in a central position at maximum yaw,

[0054] Fig. 13 shows a plan view of the displacement device of fig. 12,

[0055] Fig. 14 shows a plan view of an arm of a displacement device according to the disclosure,

[0056] Fig. 15 shows a cross-sectional view of the arm of fig. 14 along the line A- A,

[0057] Fig. 16 shows a circumferential side view of the arm of fig. 14,

[0058] Fig. 17 shows a radial side view of the arm of fig. 14,

[0059] Fig. 18 shows a perspective view of the arm of fig. 14.

[0060] Fig. 19 shows a side view of an actuator, comprising a slider and a support,

[0061] Fig. 20 shows a plan view of the actuator of fig. 19, Fig. 21 shows a cross-sectional view of an actuator comprising a linear motor,

[0062] Fig. 22 shows a cross-sectional view of a hnear motor with a central cooling channel,

[0063] Fig. 23 shows a perspective view of the linear motor of fig. 22,

[0064] Fig. 24 shows a perspective view of an embodiment of a linear motor with permanent magnets along a circular track,

[0065] Fig. 25 shows a plan view of the embodiment of fig. 24,

[0066] Fig. 26 shows a detailed view of the linear motor of fig. 24,

[0067] Fig. 27 shows an actuator comprising an electromotor drive,

[0068] Fig. 28 shows a detailed view of the actuator of fig. 27,

[0069] Fig. 29 shows a schematic view of a displacement device wherein each arm at its central end is pivotable about a respective proximal axis near the central axis,

[0070] Fig. 30 show a schematic view of a displacement device in which two arms are mounted on flanges of the first arm, Fig. 31 shows a displacement device with hnear actuators comprising a toothed belt,

[0071] Fig. 32 shows a detail of the actuators of fig. 31,

[0072] Fig. 33 shows an embodiment of a driving simulator comprising a cockpit supported by a 3 DOF displacement system comprising ball screws and cardanic joints,

[0073] Fig. 34 shows a driving simulator comprising a spherical screen mounted on a frame of the displacement device,

[0074] Fig. 35 shows an actuator comprising an axial flux curved linear motor,

[0075] Fig. 36 shows a detail of a double-sided coil unit of the actuator of fig. 35, Fig. 37 shows an actuator having lamination stacks for supporting the windings of a radial flux linear motor, and

[0076] Fig. 38 shows a detail of an annular array of permanent magnets of the actuator of fig. 37.

[0077] Detailed Description

[0078] Figure 1 shows a vehicle driving simulator 1 comprising a displacement device 2 having three arms 3, 4, 5. The arms 3-5 are connected with their ends 6, 7, 8 to a central hub 10 and are rotatable around a central axis 11. The circumferential ends 13, 14, 15 of the arms 3-5 are supported on a circular track 16 via wheel assemblies 18, 19, 20. Each arm is driven in rotation about the axis 11 by a linear actuator 22, 23,24.

[0079] A triangular frame 30 is supported on the arms 3,4,5 via carriages 31, 32, 33, one at each corner of the frame 30. The carriages 31-33 can slide in a radial direction along rails on the arms 3-5. A hexapod structure 35 comprising three pairs of actuators 37, 38, 39, such as hydraulic cylinders or electro-mechanical actuators, is attached to the frame 30 and carries a driver cabin 40.

[0080] Figure 2 shows a plan view of the driving simulator 1 of figure 1. The three arms 3, 4, 5 are each independently driven by a respective actuator 22, 23, 24 to provide an angular rotation around the central axis 11. A combination of the rotational position of each arm 3-5 results in a longitudinal displacement (x-direction), a lateral displacement (y-direction) and a yaw movement (rotation around a vertical axis) of the triangular lower frame 30. In figure 2, the arm 3 extends forward along the X-axis and the arms 4 and 5 extend at an angle a of 30 degrees with the Y-axis. The center of the frame 30 is situated on the central axis 11.

[0081] Figure 3 shows a cross-section of the carriage 31 carrying the frame 30. The carriage 31 can slide in the length direction of the arm 3 along rails 42. The carriage 31 is connected to the corner of the frame 30 via a rotational bearing 43 with a vertical rotation axis that can support the axial vertical loads and tangential loads and that can accommodate small misalignments that are the consequence of a limited flatness of the floor supporting the wheel assemblies 18-20 or of inaccuracies in the track 16.

[0082] Figures 4 and 5 show the most forward position of the triangular frame 30 and driver cabin 40 along the X-axis. The sliders 44, 46 of the linear actuators 23 and 24 are moved to their forward end position, so that the arms 4 and 5 are rotated at an angle of about -10 degrees to the Y-axis. The slider 48 of the actuator 22 is situated at its midpoint. Each slider 44, 46, 48 is connected to the circumferential end 13, 14, 15 of each arm via a pivotable push pull rod 45, 47, 49 for pushing or pulling the arms 3-5 around the central axis 11.

[0083] In case the track 16 is made of steel, electromagnets 50, 51, can be provided near each wheel of the wheel assemblies 18, 19, 20 to provide a downward force on the wheels during movement along the track 16.

[0084] The arms 3,4 and 5 are provided with sideways projecting bumper members 55, 56, 57 that limit the angle between adjacent arms. The bumper members comprise a tangential resilient end part and abut to ensure that the included angle between two adjacent arms does not become much smaller than 80 degrees (the buffer angle). This buffer angle forms the main design parameter of the system and basically defines the system geometry and excursion limits in the X and Y-directions. The other design parameter is the size or scale factor, defined by the radius of the circle on which the three corner bearings of the carriages 31, 32, 33 are located.

[0085] The required (radial) length of the arms 3, 4, 5 is a consequence of the scale factor and the buffer angle. If the buffer angle becomes too small, the minimum distance (the smallest distance that can occur within the operational range that is defined by the buffer angle) between the central axis 11 and a carriage 31, 32, 33 becomes too small to be mechanically feasible, or even negative (implying a zero crossing, which is not possible by definition).

[0086] The actuators 22, 23, 24 are controlled in such a way to ensure that the bumper members 55, 56, 57 do not contact one another under regular operating conditions.

[0087] Figures 6 and 7 show the frame 30 and the driver cabin 40 in a rearmost position along the X-axis. The carriage 31 is moved along the arm 3 to a position near the central hub 10, while carriages 32 and 33 are moved along arms 4 and 5 in the direction of the circumferential end 14, 15 of each arm. In this position, the bumper members 56, 57 of the arms 4 and 5 abut.

[0088] Figures 8 and 9 show the frame 30 and the driver cabin 40 in a right lateral end position along the Y-axis. The arms 3 and 4 extend in substantially opposite directions, and bumper members 55 and 57 or arms 3 and 5 abut.

[0089] Figures 10 and 11 show the frame 30 and the driver cabin 40 in a Left lateral end position along the Y-axis. The arms 3 and 5 extend in substantially opposite directions, and bumper members 55 and 56 or arms 3 and 4 abut.

[0090] Figures 12 and 13 show the frame 30 and the driver cabin 40 in a maximal yaw position around central axis 11. The sliders 44, 46 and 48 of the actuators 22, 23, 24 are moved to their end positions. At the end section of each actuator, a resilient stopper 59, 60 is provided for absorbing the inadvertent impact of the sliders 44, 46, 48 at their end positions in case of a control failure.

[0091] Figure 14 shows the arm 3 in plan view with at its circumferential end 13 the wheel assembly 18. The wheels 62, 63 are mounted on a cross beam 66. The axes 64, 65 of the wheels 62, 63 are at an angle to the length direction of the arm 3 and intersect at the central axis 11. As is clear from the cross-sectional view of figure 15, the carriage 31 is supported on two parallel rails 41, 42 via linear bearings 67, 68, that may be executed as sliding bearings or bearings containing rolling elements.

[0092] At the circumferential end 13, the arm 3 is provided with a flange plate 61 comprising an eye for connection to the push pull rod 49 of the slider 48.

[0093] Figures 16, 17 and 18 show a circumferential sideview, a radial sideview and a perspective view of the arm 3, respectively. The electromagnets 52, 54 are positioned in proximity to the wheels 62, 63 to prevent vertical movements of the wheels when rolling along the track 16 under upward loads.

[0094] Irrespective of the longitudinal, lateral and yaw position of the triangular mounting frame, and of the corresponding positions of the carriage and arm angles, each corner point of the mounting frame 30 is properly supported by the two wheels 62, 63 and the central hub 10. The center of the lower frame 30 is always located well within the circle described by the wheels. The radial location of the cross beam 66 to which the wheels are mounted, is optimized in order to provide the highest possible vertical stiffness along the entire operational range of the carriage on the rails.

[0095] The system according to the disclosure can be executed in a number of ways. In a reduced-cost version, commercially available PU-sleeved steel wheels can run directly on a good quality concrete floor that is sufficiently flat. The three arms are driven by linear actuators, by means of push-pull rods. The linear actuators can comprise a linear motor, as depicted in figures 19-23, but may also comprise a commercially available toothed belt actuator.

[0096] Alternatively, steel plates may be mounted on a concrete floor in combination with hardened steel wheels that can run on these plates. Should it be required to handle upward forces as well as downward forces, each wheel can be equipped with an adjacent electro-magnet to provide an attraction force that augments the gravity force. Rubber sleeved friction wheels may also be used on a steel plate, in which case the rubber wheels are driven by electric motors. Each of the six wheels may be equipped with a corresponding motor. Because of limited slip occurring between a friction wheel and the steel plate surface, the motor rotational absolute position (multi turn encoder) is not representative for the arm position, so that in this version an absolute measuring system needs to be provided on each arm. This version can provide infinite rotation at comparatively low cost. Should it be required to increase the contact force between friction wheels and steel plate, each wheel can be equipped with an adjacent controlled electro-magnet to provide an attraction force that augments the gravity force.

[0097] The linear actuator that drives each arm may be executed as a straight line or as a curved motor. In the latter case the three arms may be driven by short push pull rods.

[0098] Figures 19-23 show a linear motor 75 with two L-shaped flanges 76, 77 carrying permanent magnets 78, 79. A housing 81 carrying independent back-to-back coil units with windings 82, 83 that share a common lamination stack, is slidably connected to rails 87, 88 that are mounted on the flanges 76, 77, via slide bearings 84, 85. By powering the magnetic coils 82, 83, the housing 81 is moved in the direction perpendicular to the plane of the drawing. The housing 81 is connected to an arm of the displacement device via a push pull rod (not shown in the drawing).

[0099] In figure 22 a cooling channel 90, 91 is shown in the lamination stack for circulating a coolant through the core of the windings 82, 83.

[0100] Figure 23 shows the linear motor 75 with the housing 81carrying the windings 82, 83 and slidable along the flanges 76, 77 supporting the permanent magnets 78, 79. Figures 24 and 25 show a vehicle driving simulator 1 with a displacement device 2 having a circular set of permanent magnets 100, a movable housing 103, 104, 105 each carrying windings and a push pull rod 102, 106, 107 connected to a circumferential end of the arms 3, 4, 5. In this design there is a low precision part (the three arms running on a low precision surface) and a high precision part (the curved linear motor). It is possible to increase the precision of the three arms and the support surface, to connect the curved coil units directly to the outer end of each arm and omit the curved guiding rails of the curved linear motor.

[0101] Figure 26 shows the arm 3 that is connected to an actuator with circular stationary permanent magnets 100, 108, as a slider a movable housing 103 carrying the windings 110 and short push-pull rod 102 connected to the flange plate 61 of the arm 3.

[0102] Figure 27 shows the wheel assemblies 18, 19, 20 being provided with rubber friction wheels and electromotor drives 120, 121, 122, 123, 124, 125, one drive connected to each wheel of the assemblies 18-20.

[0103] Figure 28 shows the wheels 63, 64 and the connected electromotors 120, 125 on an enlarged scale.

[0104] Figure 29 shows an embodiment in which the arms 3, 4, 5 are mounted on respective hubs and are pivotable around respective proximal axes 130, 131 and 132, that are situated near central axis 11. This construction has limited yaw capability.

[0105] Figure 30 shows an embodiment in which the proximal axes 141, 142 of the arms 4, 5 are positioned on a flange 143, 144 of the arm 3. The arm 3 can rotate about the central axis 11. This configuration is similar to the configuration of connecting rods in a radial engine and provides infinite yaw capability.

[0106] Figure 31 shows a driving simulator 1 in which the linear actuators 22, 23 and 24 are each formed by a straight rail section 150 carrying a toothed belt 151, that is driven by an electric motor 152. A slider 153 is moved by the belt 151 along the support section 150 and is connected to the end part of each arm 3, 4, 5 via a push-pull rod 155.

[0107] The 3 DOF secondary motion system in this embodiment comprises three ballscrew actuators 160, 161 that are connected to the cockpit or driver cabin 40 and that are supported on the frame 30 via cardanic joints 162 (see fig. 33).

[0108] Two .rods 165, 166 pivotally connect the cabin 40 to support posts 167, 168 on the frame 30. The transverse side 169 of the cabin 40 is connected to the posts 167, 168 via a Watt linkage 170 which maintains a controlled vertical motion of the cabin without lateral displacement.

[0109] Figure 32 shows in more detail the toothed belt 151 driving the slider 153 along two tracks 157, 158 on the support section 150.

[0110] Figure 33 shows the three ball screw actuators 160, 161, 164 and the cardanic joint 162 in more detail.

[0111] Figure 34 shows a driving simulator 1 having a spherical screen 175 supported on the frame 30. The frame 3O.is driven by a direct drive curved linear motor with permanent magnets 100 that are arranged along a circular track having a diameter of for instance 12 m. From the cockpit 40, a realistic wide-angle view of a simulated driving environment is observed on the screen 175 by the driver.

[0112] Figure 35 shows an actuator for driving the arm 3 comprising an axial flux motor having a ring 100 of permanent magnets 181,182 that are supported on the top and on the bottom of a disc-shaped magnet carrier 183. The coils that are supported by the cross beam 66 are schematically indicated at 180 and are oriented substantially parallel to the support surface of the wheels 62, 63, to generate an axial flux in a direction perpendicular to the support surface. Figure 36 shows the arrangement of the coils 180 and 185 on each side of the magnet carrier 183, which has been omitted from the figure.

[0113] Figure 37 shows an arrangement of a direct drive curved linear radial flux motor with the lamination stack element 187 mounted on the cross beam 66 of the arm 3. The coils, which are not shown in the figure, are wound around the laminated core projections of the element 187 and generate a magnetic flux in the radial direction of the arm 3.

[0114] Figure 38 shows the arrangement of the permanent magnets 191, 192 on the ring 100 of the radial flux motor.

Claims

Claims1. Displacement device (2) comprising:- a support surface (16), a central axis (11) extending perpendicularly to the support surface, and three arms (3, 4, 5) that are each connected with their central ends (6, 7, 8) to be rotatable around a proximal axis (130, 131, 132, 140, 141) that is situated on or near the central axis (11) and with a circumferential end (13, 14, 15) movably supported on the support surface (16),- each arm (3, 4, 5) supporting a radial displacement member (31, 32, 33) that is movable along the respective arm in a radial direction, the displacement members being rotatably connected to a mounting frame (30) and- actuators (22, 23, 24, 75, 120-125) that are adapted for rotating the arms (3, 4, 5) around the central axis (11) so that the displacement members (31, 32, 33) can move radially along the respective arms whereby the mounting frame (30) is moved.

2. Displacement device according to claim 1, wherein the proximal axes of all arms are situated on the central axis (11), the arms being connected to a central hub (10).

3. Displacement device (2) according to claim 1 or 2, comprising a driving simulator (1) with a movement mechanism (35) having 1 - 6 degrees of freedom that is connected to the mounting frame (30) and a driver cabin (40) supported by the movement mechanism (35).

4. Displacement device (2) according to any of the preceding claims, each arm (3, 4, 5) comprising a tangential damping member (55, 56, 57) projecting from the arm in a tangential direction, so that upon rotation of the arms around the central axis (11), the damping members of adjacentarms abut when a predetermined minimum angle is included between the adjacent arms.

5. Displacement device (2) according to claim 4, wherein the predetermined minimum angle is between 60 and 100 degrees, preferably between 70 and 90 degrees, most preferably about 80 degrees.

6. Displacement device (2) according to any of the preceding claims, the radial displacement member (31, 32, 33) comprising a carriage that is slidably connected to rails (41, 42) extending in a length direction of the arms (3, 4, 5).

7. Displacement device (2) according to claim 6, the carriage supporting the mounting frame (30) via a bearing (43), the cross-section of which in a plane of the central axis (11), has a curved surface, the bearing (43) taking up forces in a direction of the central axis and tangential forces and accommodating misalignment angles.

8. Displacement device (2) according to any of the preceding claims, the arms (3, 4, 5) being at their circumferential ends (13, 14, 15) supported by wheels (62, 63) running on the support surface (16) and having a wheel axis (64, 65) that extends in the direction of the central axis (11).

9. Displacement device (2) according to claim 8, each arm comprising near its circumferential end (13, 14, 15) a transverse beam (66) supporting a wheel (62, 63) on each end.

10. Displacement device (2) according to any of the preceding claims, each arm (3, 4, 5) being connected to an actuator (22, 23, 24) comprising a sliding member (44, 46, 48, 81, 153) that is movable along a support member(76, 77, 150), the sliding member being attached to a circumferential end (13, 14, 15) of a respective arm via a pivoting actuator rod (45, 47, 49, 155).

11. Displacement device (2) according to any of the preceding claims, comprising electrical windings (82, 83; 110; 180, 185) at a circumferential end (13, 14, 15) of the arms (3, 4, 5), the windings being situated near a support member (76, 77) comprising permanent magnets (78, 79; 100, 108; 181, 182; 191, 192) forming a curved linear motor.

12. Displacement device (2) according to claim 8 or 9, the actuator comprising at least one motor drive (120, 121, 122, 123, 124, 125) connected to a wheel (63, 64) of each arm (3, 4, 5) for driving the wheels in rotation.

13. Displacement device (2) according to any of the preceding claims, each arm (4, 5, 6) comprising near its circumferential end (13, 14, 15) a downward force member (50-54) exerting a downward force on the arm (3, 4, 5).

14. Displacement device (2) according to any of the preceding claims, comprising a curved screen (175) mounted on the frame (30).

15. Method of positioning an object in a plane by placing the object on a displacement device (2) according to any of the preceding claims, determining the object’s coordinates in a target position in the plane and rotating each arm (3, 4, 5) through an angle around the central axis (11) corresponding to the target position.

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