NL2023724B1

NL2023724B1 - Driving simulator

Info

Publication number: NL2023724B1
Application number: NL2023724A
Authority: NL
Inventors: Theodoor Jacob Van Lookeren Campagne Pieter; Van Egmond Erik; De Waard Bas
Original assignee: E2M Tech B V
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2021-05-11

Abstract

The invention is directed to a driving simulator suited to generate motion impressions for test persons comprising a motion system comprising a base and a moveable platform 5 having one or more degrees of freedom connected to the base by means of one or more actuators and a cabin connected to the moveable platform comprising a seat for the test person and driving controller elements for the test person. The base of the motion system is moveable in a horizontal plane at a distance above a floor. The base is connected to a beam which beam is pivotally connected via a pivot point at one end ofthe beam to the floor and 10 supported on the floor with two or more moveable support means which allow the beam to pivot around its pivot point at a distance from the floor. [Fig. 3] 2023724

Description

DRIVING SIMULATOR The invention is directed to a driving simulator suited to generate motion impressions for test persons comprising a motion system comprising a base and a moveable platform having one or more degrees of freedom connected to the base by means of one or more actuators, and a cabin connected to the moveable platform comprising a seat for the test person and driving controller elements for the test person. The base of the motion system is moveable in a horizontal plane at a distance above a floor.

Such driving simulators are known and for example described in FR2677155. This publication describes a vehicle as the cabin positioned on a motion platform. The base of the motion platform is moveable along a bridge and the bridge itself is moveable along three rails in a simulated driving direction. In this manner a test person can be subjected to small, high frequency movements by means of the motion platform and to large, lower frequency movements, like braking and acceleration, using the moving bridge. Lane changing movements may be simulated by movement of the motion platform along the length of the bridge. A screen on which a simulated environment is projected is connected to the moveable platform of the motion system. Although such a driving simulator is suited to subject a test driver to a driving experience close to real driving some disadvantages remain. One problem is that the movement of the motion platform along the bridge will create a large reaction force on the bearings supporting the bridge on the three rails. A next disadvantage is that the rails need to be positioned very accurately to be absolutely parallel in one horizontal plane. This requires a special concrete floor wherein provisions for the rails are poured together with the concrete. This makes the installation of the driving simulator very complex.

Similar driving simulators as described above are known from US2005042578. This publication describes a vehicle as the cabin positioned on a motion platform. The motion platform is mounted on a carriage which can move in a 40 by 40 meters planar base surface by means of air bearings and air cushions. The movement is achieved using a gantry bridge. The gantry bridge can move along two rails in one direction. The motion platform on air bearings is connected to the gantry bridge and can move along the length of the gantry bridge equipped with linear motors . In this manner two perpendicular movements of the motion platform in the horizontal plane are achieved. Such a driving simulator requires a large flat steel surface which is very complex to manufacture, W02014114409 describes a driving simulator having a slide rail on which a yaw-table is moveably connected. On the yaw-table a hexapod motion platform is positioned. On the moveable platform of the motion system a driver cabin is positioned. The screen on which a simulated environment is projected is connected to the yaw-table. This driving simulator can only simulate large, low frequency movements in one direction. This may be sufficient to simulate certain driving experiences such as lane changing. A disadvantage is however that the slide rails requires to be manufactured very accurately. A further disadvantage is that the force required to move the relatively heavy yaw-table, screen, cabin and motion platform along the slide rail is high.

The object of the present invention is to simplify the known driving simulator. This object is achieved by the following driving simulator. Driving simulator suited to generate motion impressions for test persons comprising - a motion system comprising a base and a moveable platform having one or more degrees of freedom connected to the base by means of one or more actuators, and - a cabin connected to the moveable platform comprising a seat for the test person and driving controller elements for the test person, - wherein the base of the motion system is moveable in a horizontal plane at a distance above a floor and - wherein the base is connected to a beam which beam is pivotally connected via a pivot point at one end of the beam to the floor and supported on the floor with two or more moveable support means which allow the beam to pivot around its pivot point at a distance from the floor.

Applicants found that by using a pivoting beam as a means to create the large, low frequency movements in at least one direction a more simple design is obtained. It has been found that the driving simulator can be used in combination with a standard factory floor and does not require specially adapted floors as in the prior art simulators. The pivot point can be simply anchored into a standard factory floor. The support means of the beam will travel along a defined curved pathway which requires much less adaptation of the floor than inthe prior art design where the entire floor work space of the moving platform was required to be of dedicated design. Further the force to pivot the beam and thus move the test person in one direction can be less than in the prior art designs because the beam design makes leveraging of a force possible. Further advantages will be described when discussing the preferred embodiments below.

The driving simulator comprises a motion system comprising a base and a moveable platform having one or more degrees of freedom. The moveable platform is connected to the base by means of one or more actuators. The degrees of freedom of the moveable platform relative to the base may be from one to six degrees of freedom. An example of a one degree of freedom motion system is a system wherein the platform can only move in the vertical direction. Examples of motion platforms having three degrees of freedom may be platforms having a pitch, roll and heave movement. For motion systems having less than 6 degrees of freedom additional mechanical means, such as push-pull rods or scissor mechanisms, may be present to lock the non-active degrees of freedom.

Preferably the motion system has a moveable platform having six degrees of freedom relative to the base. An example of such a motion system having six degrees of freedom is the well-known Stewart Platform having six actuators. Further examples are described in applicants patent US9842509. The number of actuators may be larger than the number of degrees of freedom. An example of such a motion system is described in applicants WO2017/202920 and EP3489932 which publications illustrate a motion system having six degrees of freedom and eight actuators connecting the base with the moveable platform. The actuator of the motion system may be a hydraulic actuator. Preferably the actuator is an electro mechanical actuator, more preferably an electromechanical in-line actuator type comprising a motor directly mounted on the ball screw shaft of the electromechanical actuator.

In a first embodiment of the driving simulator the motion system is fixed to the beam. This in contrast to a second embodiment wherein the motion system is moveably connected to the beam allowing movement of the motion system along the length of the beam by means of a drive system.

The first embodiment is advantageous because it provides a simple method to create large, low frequency movements, in one direction. Because the beam pivots around its pivot point the resulting movement will be a movement along a section of a circle. The motion system may compensate this circular component such that the test driver experiences a translational movement. Preferably at least part of the circular movement is compensated by rotatably connecting the cabin along the yaw-axis to the moveable platform. In this way the motion system does not have to compensate the entire circular component of the movement. This may be achieved by a yaw-table rotatably positioned on the moveable platform of the motion system or by positioning the motion system on a yaw table as described in for example W02014114409.

More preferably the circular movement is compensated for the rotation by the yaw table and for the unwanted longitudinal translation by a surge movement of the preferred six degrees of freedom motion system.

The first embodiment may be advantageously used in a method to simulate lane changing of a vehicle. The invention is for this reason also directed to the following method.

Method to simulate a lane changing driving experience by positioning a test driver in a cabin equipped with driver control means, moving the cabin by means of a six degree of freedom motion system and projecting a simulated environment around the cabin such that the test driver experiences a driving direction in the x-direction and wherein a lane changing driving experience is simulated by moving the cabin and motion system along a section of a curve in a direction substantially perpendicular to the simulated driving direction resulting in a curved motion of the cabin and compensating the curved motion of the cabin by rotating the cabin relative to the motion system along the yaw-axis and moving the cabin in the x-

direction resulting in a more perpendicular movement of the cabin relative to the simulated driving direction. The rotatable connection around the yaw axis may also be used to turn the cabin 90 degrees and thus the simulated driving direction by 90 degrees. In this manner the same driving simulator may be used for testing another driving feature of the vehicle, 5 for example braking and acceleration. The method is preferably performed using a driving simulator according to the invention.

In the above method the acceleration and/or brake driving experience is provided by the movements of the motion system. If the acceleration and/or brake driving experience is to be enhanced it is preferred that the method also includes a movement of the cabin and motion system in the simulated driving direction. This movement will be in the driving direction and in the opposite driving direction. The reaction forces of the moving motion system and cabin along the beam can be easily absorbed by the pivot point. This requires much less special measures as compared to when such a force is to be absorbed by the bearings as in for example FR2677155, where some backlash is usually present to compensate for minor misalignment in the rails In the second embodiment the base of the motion system is moveably connected to the beam allowing movement of the motion system along the length of the beam by means of a drive system. Such a connection may be by linear guiding, for example by means of track rollers. The drive system may be any system suited to move the motion system along the beam. Examples of such drive systems are belts, for example steel flat belts, steel cables, actuators, for example ball-screw actuators and rack & pinion. Preferably the drive system is an electromagnetic linear motor because it can achieve high speeds at almost zero noise and at an almost infinite control rigidity.

For the second embodiment it may be preferred to use a six degrees of freedom motion system having eight actuators as described above. Such an octopod can resist accelerations in the direction of the beam and accelerations in the direction of the section of a circle resulting from the pivot movement of the beam better than for example the well-

known hexapod having six actuators. Further the base of an octopod is typically square, wherein the mounting positions of the eight actuators are in the corners of the square. Such a square base is more easily to be made compatible with a linear guiding, comprising for instance track rollers at its four corners, resulting in a direct load transfer path from motion system actuators to track rollers and consequently a high rigidity.

Also for the second embodiment it is preferred to connect the cabin to the moveable platform along a moveable yaw axis for the same reasons as described above. When the motion system moves towards the beam pivot point, for instance when simulating an acceleration of the vehicle, and for a given lateral displacement, required by simulation of a simultaneous lateral acceleration, the unwanted yaw also increases. This is best compensated by the moveable yaw axis.

The cabin is directly or indirectly via a yaw-table connected to the moveable platform. The cabin comprises a seat for the test person and driving controller elements for the test person. These driver controller elements may be those used in a vehicle to be simulated and may include a steering wheel, a brake pedal and a throttle pedal. To enhance the simulation it is preferred to use a real version of the vehicle to be tested as the cabin or to use a part of the real vehicle. The vehicle will first be stripped from any heavy elements, such as the engine, transmission, suspension and wheels, and the controller elements will be connected to a simulation algorithm. Instead of using the stripped vehicle to be simulated as the cabin it is also possible to place the test person on a seat eguipped with the controller elements and simulate the car and its driving environment using virtual reality visual means, like a VR headset.

The driving environment will be simulated for the test driver by for example the earlier referred to virtual reality visual means. Suitably the driving environment is simulated by projecting this environment on a screen which surrounds the test person. Such a screen may be connected to the moveable platform of the motion system as in FR2677155. More preferably the screen for projecting a simulated environment for the test driver is connected to the beam. This is especially preferred for the above described first embodiment. Also for the second embodiment such a connection may be preferred in case the possible movement of the motion platform along the length of the beam is relatively small. In case such a movement is larger it may be preferred to connect the screen for projecting a simulated environment for the test driver to the base of the motion platform. In that manner the screen will also move with the motion system and cabin along the length of the beam. lt is advantageous to connect the screen to either the beam or to the base of the motion system because this will lower the weight carried by the moveable platform of the motion system.

The beam is supported at its pivot point and by at least two moveable support means on a floor. Because the beam is supported by at least three points it will be stable. The pivot point or pivot axis may be an axle anchored in the floor and wherein the beam comprises bearings along which the beam may rotate around the axle. The two or more support means may be wheels having an axis of rotation directed to the pivot point of the beam. The wheels may for example be solid metal wheels, preferably steel wheels, or wheels having a polyurethane rim. The two or more support means may also be air bearings optionally in combination with magnets.

The support means, such as wheels, can be used directly onto a floor. For example polyurethane rimmed wheels may be used directly on a concrete floor. The support means may also run along a support surface attached to the floor located at the possible pathway of the support means. The support surface follows the path way of the support means substantially along a section of a circle having the distance to the pivot point as its radius. A preferred support is a steel plate surface suited to use in combination with steel wheels as the moveable support means. The support or the floor may be relatively inaccurate as long as the noise or vibrations generated by the moveable support means is substantially smaller than the noise or vibrations generated by the motion system simulating a driving experience. This allows one to use wheels as described above. This does not exclude that one may also choose for the more complex air bearings optionally in combination with magnets in combination with a machined steel strip as the support.

The driving simulator has a drive system to pivot the beam around its pivot point, This drive system may be comprised of belts, for example steel flat belts, steel cables, actuators, for example ball-screw actuators. The drive system may be a rack & pinion running along the support surface for the supporting means. The drive system may be a curved electromagnetic linear motor running along the support surface. The drive means may also exist of motors, directly coupled to supporting wheels, for example wheels provided with direct drive motors.

Preferably a drive system is present comprising an electromagnetic linear motor. Suitably the beam is connected to the electromagnetic linear motor at its outer radial end at about the same elevation above the floor as the centre of gravity (COG) of the combined beam, motion system and cabin and optional screen. This minimizes the load transfer from one moveable support to another moveable support. The electromagnetic linear motor is preferably a straight electromagnetic linear motor. Because the radial end of the beam which will travel along a section of a circle can be connected to the straight electromagnetic linear motor by known means, such as by a push-pull rod or by a pin and slotted hole configuration.

The dimensions of the drive simulator should be sufficient to achieve the desired movement sensation for the test person and the test goal. The main dimension of the drive simulator will be the length of the beam. The length may be between 8 and 25 meters. This length does not include any bolted or welded on extensions to the radial outer part of the beam. Higher length of the beam may become unpractical because the beams may then become difficult to transport. if the beam can be assembled at the location of use this upper limit of length may be less relevant. Especially for the first embodiment longer length of the beam may be possible. For the second embodiment it is preferred to use a beam made of a welded or riveted structure and wherein the interfaces for the guiding rails are machined in asingle milling operation.

The driving simulator may have a control room from which the simulated environment, suspension and control parameters, can be varied. This control room preferably has a view towards the motion system-cabin combination. Preferably the control room positioned above the pivot point. In the first embodiment it is clear that the moving motion system-cabin will not interfere with a control room at that position. But also in the second embodiment no interference is expected because the practical movement envelope of the motion system-cabin along the length of the beam terminates at some point before the pivot point. The invention will be illustrated using the following non-limiting Figures 1-5 Figure 1 shows a drive simulator (1) according to the first embodiment. A hexapod motion system (2) comprising a base (3) and a moveable platform (4). The moveable platform (4) is connected to the base (3) by means of six actuators (5). The actuators (5) are of the linear electromechanical type. The moveable platform (4) has six degrees of freedom. A vehicle (6) is shown as the cabin for the test driver and connected to the moveable platform (4). The vehicle (6) will at least be provided with a seat for a test driver, brakes and power means. Further a beam (7) is shown manufactured as a framework which is pivotally connected via a pivot point (8) at one end (9) of the beam (7) to a floor (10). The beam (7) may be manufactured as a framework because the motion system {2} and vehicle {6) do not move in the direction of the length of the beam. This results in that the forces on the beam will be less and that the beam can be manufactured as a framework. This in turn is advantageous because it is lighter than a beam suitably used for the second embodiment. The base (3) of motion system (2) is part of the framework of beam (7). The beam {7} is further supported by two steel wheels {11}, of which only one is visible from this angle, as the two support means at the opposite end (12) of the beam. The wheels {11) and the pivot point (8) allows the beam {7} to pivot around its pivot point at a distance from the floor (10). The two wheels {11} run on a support surface (13) attached to floor {10). The support surface (13) is a steel strip on which the steel wheels {11} run. A screen (14) for projecting a simulated environment for the test driver is connected to the beam (7).

In Figure 1 a drive system {15} is shown which can pivot the beam (7) around its pivot point {8}. This drive system (15) comprises of a straight electromagnetic linear motor (16). The straight electromagnetic linear motor (16) comprises of a moving carriage (16a) and rails (16b} supporting coil unit and permanent magnets of the linear motor or vice versa of the linear motor. The straight electromagnetic linear motor (16) is positioned tangentially with respect to the curved support surface (13) just radially away from the circular pathway of the radial outer end (18) of the beam (7). The outer radial end {18) of the beam (7) is connected to the moving part (16a) of the straight electromagnetic linear motor (16) by a push-pull rod {17}. The centre of gravity (COG) of the combined beam (7), motion system (2), screen (14) and vehicle (6) will be relatively close to the floor (10) because the base (3) of the motion system is combined with the lower beams of the framework of the beam (7). The elevation of the outer radial end (18) will in this figure be about the same elevation above the floor {10) as said centre of gravity (COG). Figure 2 shows the drive simulator of Figure 1 from a different angle. Part of the screen {14) is cut open to see more details. Obviously the screen will be closed in the actual application. In Figure 3 shows a drive simulator (20) according to the second embodiment. Elements having the same reference number will have the same function as in Figure 1. Drive simulator (20) is provided with a welded or riveted structure as beam (7). An octopod motion system (2) is provided with a base (3) to which a screen (14) is connected. The base (3) is moveably connected to the beam (7) as illustrated in Figure 5. An electromagnetic linear motor may be present as drive means to move the motion system (2) and vehicle (6) along the length of the beam (7). The support means are two wheels (11). As shown the support means are not positioned at the radial outer end of the beam as in Figure 1 but more close to the possible positions of the motion system {2} and vehicle {6} on the beam. This to provide the optimal local support for the beam. Figure 4 shows the drive simulator {20} of Figure 2 from another angle. A control room {19} is shown to be present above the pivot point (8).

Figure 5 shows a cross-sectional view of the beam (7) of Figures 3-4. Beam {7} is a single metal part on which extremely flat interface surfaces (22) are machined. Onto these flat surfaces hard steel rails (26) are positioned which extends as an extension (26a) outwards according to a well-defined distance. Also shown is a carriage (21) which can move along the length of the beam. Carriage (21) supports the motion system and cabin which are not shown in this Figure. Carriage (21) may have a square design. To carriage (21),

preferably approximately below each of its four corners, a set of track rollers {23,24,25} are present which engage with the extension (26a).

Claims

CONCLUSIONS l. Driving simulator adapted to generate motion impressions for test subjects, comprising: a motion system comprising a base and also comprising a movable platform with one or more degrees of freedom connected to the base by means of one or more actuators, and connected to the movable platform, and comprising a seat for the test taker and control controls for the test taker, e in which the base of the movement system is movable in a horizontal plane at a distance above a floor, and e in which the base is connected having a beam pivotally connected through a pivot at one end of the beam to the floor, and supported on the floor by two or more movable support means which permit the beam to pivot about its pivot at a distance of relative to the floor.

Driving simulator according to claim 1, wherein the cabin is rotatably connected to the movable platform along the yaw axis.

A driving simulator according to any one of claims 1 to 2, wherein the base of the movement system is movably connected to the beam, allowing movement of the movement system along the length of the beam by means of a drive system.

The driving simulator of claim 3, wherein the drive system is an electromagnetic linear motor.

A driving simulator according to any one of claims 1 to 4, wherein a screen for projecting a simulated environment for the test driver is connected to the base of the motion platform.

A driving simulator according to any one of claims 1 to 2, wherein a screen for projecting a simulated environment for the test driver is connected to the beam.

Rig simulator according to any one of claims 1 to 6, wherein the two or more support means are wheels with an axis of rotation each directed towards the pivot axis of the beam.

A driving simulator according to any one of claims 1 to 8, wherein the two or more support means are air bearings, optionally in combination with magnets.

A driving simulator according to any one of claims 7 to 8, wherein the support means run along a support surface connected to the floor, located on the possible trajectory of the support means.

A driving simulator according to any one of claims 1 to 9, wherein a drive system is provided that can rotate the beam about its pivot point, and wherein the drive system comprises an electromagnetic linear motor.

Driving simulator according to claim 10, wherein the beam is connected to the electromagnetic linear motor at its outer radial end, approximately at the same height above the floor as the center of gravity (COG) of the combination consisting of the beam, the movement system, and the cabin, and possibly the screen.

A driving simulator according to any one of claims 10 to 11, wherein the electromagnetic linear motor is a straight electromagnetic linear motor, and wherein the beam is connected to the straight electromagnetic linear motor at its outer radial end,

A driving simulator according to claim 12, wherein the outer radial end of the beam is connected to the straight electromagnetic linear motor by a double acting rod or by a pin and slotted hole configuration.

A driving simulator according to any one of claims 1 to 13, wherein the length of the beam is between 8 m and 25 m.

A driving simulator according to any one of claims 1 to 14, wherein the simulator further comprises a control room positioned above the pivot point.

A driving simulator according to any one of claims 1 to 15, wherein the movement system comprises a movable platform with six degrees of freedom.

The driving simulator of claim 16, wherein the motion system comprises six actuators.

The driving simulator of claim 16, wherein the motion system comprises eight actuators.

19. Method of simulating a lane change driving experience by positioning a test driver in a cab equipped with steering controls, moving the cab using a six degrees of freedom motion system, and projecting a simulated environment around the cab in such a way that the test driver experiences a direction of travel in the X direction and simulates a lane change driving experience by moving the cab and motion system along a section of a bend in a direction substantially perpendicular to the simulated direction of travel, resulting in a curve motion of the cab, and compensating for the curve motion of the cab by rotating the cab relative to the motion system along the yaw axis, and moving the cab in the X direction, resulting in a more perpendicular movement of the cab relative to the simulated direction of travel ng.

A method according to claim 19, wherein the acceleration and/or braking driving experience is enhanced by moving the cab and the movement system in the simulated driving direction.

A method according to any one of claims 19 to 20, using a driving simulator according to any one of claims 2 to 18.