WO2014114409A1

WO2014114409A1 - Driving simulator

Info

Publication number: WO2014114409A1
Application number: PCT/EP2013/076739
Authority: WO
Inventors: Jean Paul WARMERDAM
Original assignee: Moog BV
Current assignee: Moog BV
Priority date: 2013-01-23
Filing date: 2013-12-16
Publication date: 2014-07-31
Anticipated expiration: 2015-07-23
Also published as: GB201301151D0

Abstract

A driving simulator (100) comprises a slide rail (102) on which a yaw table (104) is mounted on which a hexapod (106) is mounted in turn, the hexapod providing acceleration input to a cabin (108) surrounded by a projection dome (110) carried on the static part of the yaw table (104).

Description

Driving simulator

The present invention is concerned with a simulator. More specifically, the present invention is concerned with a driving simulator for simulating a land vehicle driving experience using both motional and visual stimuli.

Driving simulators are known. The intention of a driving simulator is to provide a combined visual and motional experience for the user which simulates the effects of driving a vehicle along a highway or other surface. This allows the product (i.e. the vehicle equipment) to be tested in a controlled environment which facilitates product development. Generally speaking, a driving simulator will comprise a vehicle cabin or cockpit and a display screen, visible to the driver which simulates the view of a surrounding environment. The image is typically projected onto the interior surface of a dome surrounding the cabin. Such simulation may use video or computer generated imagery.

Simulators also typically comprise an apparatus supporting the cabin and dome, which apparatus provides acceleration cues to the driver in order to simulate the forces experienced whilst driving a real vehicle.

Forces experienced during driving typically fall into two categories. The first type of forces result in high frequency, low amplitude accelerations, for example due to an uneven road surface. The second type of forces result in lower frequency, higher amplitude accelerations, such as those experience under acceleration, braking and steering for example.

In the field of simulators, linear accelerations in the direction of travel are commonly known as surge, side-to-side accelerations are known as sway, and vertical accelerations as heave. Rotational accelerations are known as roll (about an axis parallel to the direction of travel), pitch (about a side-to-side axis) and yaw (about a vertical axis). The motional apparatus of known simulators often comprises a hexapod. Hexapods, (also known as Stewart platforms) provide acceleration cues in six degrees of freedom in order to simulate surge, sway, heave, roll, pitch and yaw. Although hexapods can provide motion in six degrees of freedom, their workspace is limited. Therefore they are very good at providing the high frequency, low amplitude acceleration cues discussed above, but not as good at providing the lower frequency high amplitude cues (because their workspace is limited.

A known simulator which attempts to overcome this problem is shown in FR2677155. In this particular simulator, a hexapod is supported on a two-way Cartesian slide rail in order to provide high amplitude sway and surge accelerations. It will be noted that this particular arrangement requires a significant amount of floor space due to the two dimensional nature of the combined slide rails. This is undesirable. The problem of space is addressed by the simulator shown in US2007/0018511. In this document, the vehicle cabin is mounted on a yaw table such that it can be freely rotated about a yaw axis. The yaw table is in turn mounted on a hexapod which can move both the yaw table and cabin and dome in six degrees of freedom to provide the aforementioned high frequency motion cues. The hexapod is in turn mounted on a single slide rail which can provide high amplitude linear accelerations.

This device is arranged such that all required high amplitude linear accelerations can be provided by the single slide rail. For example, should the driver wish to accelerate or brake heavily (surge), then the vehicle is oriented facing in the direction of travel of the slide rail by the yaw table. Should side-to-side motion be desired (i.e., a sway acceleration) then the turntable can rotate the vehicle through 90 degrees (at a low rate, without the driver perceiving such rotation) and side-to-side accelerations can be provided by the slide rail. It will be noted with in US '511, the entire vehicle cabin, yaw table and dome containing the projection system are moved by the hexapod. As such, the hexapod has to actuate a significant load, and as a result is large and therefore expensive. This is not ideal as hexapods are expensive (they require a minimum of six linear actuators). Having a large hexapod also reduces the stiffness of the assembly.

It will also be noted that any high frequency input provided by the hexapod will move the display screen as well as the dome, therefore reducing the realism of the simulation (in real life, the car would vibrate independently of its surroundings).

It is an object of the present invention to overcome or at least mitigate the above mentioned problems with the prior art.

According to a first aspect of the invention there is provided a vehicle simulator comprising:

a linear motion assembly having a static part and a moving part;

a yaw table motion assembly having a static part and moving part;

a motion simulator having at least 4 degrees of freedom; and,

a simulator platform;

in which:

the static part of the yaw table motion assembly is mounted to the moving part of the linear motion assembly for linear movement relative to the static part of the linear motion assembly;

the motion simulator is mounted to the moving part of the yaw table motion assembly for rotational movement relative to the static part of the yaw table motion assembly; and,

the simulator platform is mounted to the motion simulator.

By "linear motion assembly" we mean a system in which the moving part moves along a fixed path, or line. The path or line may be straight or curved.

By "simulator platform" we mean a general structure to which the motion cues of the invention are applied. The platform may be any shape or configuration- it need not comprise a flat surface and may simply be e.g. part of a car body or a space frame as required. By "motion simulator" we mean an apparatus which can provide motion cues in the required at least 4 degrees of freedom. The motion simulator may be a hexapod.

Advantageously, providing the motion simulator mounted on the yaw table, rather than the other way round, means that the motion simulator does not need to move the yaw table, and as such can be made much more compact. This saves significant cost and complexity and makes the simulator a lot stiffer which improves responsiveness. Evidently, the yaw table may need to be larger and potentially more expensive than the yaw table of the prior art (because it now needs to move the motion simulator), however, yaw tables are much simpler and cheaper to construct than motion simulators such as hexapods and, as such, there is an overall saving in cost and complexity.

Preferably, the vehicle simulator comprises a display screen, in which the display screen is mounted to the static part of the yaw table motion assembly. Advantageously, neither the yaw table nor the hexapod needs to move the display screen. This is more realistic than the prior art, because the surrounding environment of the driver can remain static whilst the cabin moves. One exception to this is when the vehicle needs be rotated to change the slide rail to provide sway or surge. When this occurs, the image on the screen is moved simultaneously with the cabin in the yaw direction in order to provide a smooth, uninterrupted simulation to the driver. Coupled with the low yaw acceleration, the driver is unaware that the cabin is rotating within the dome. The ability to move the image with the vehicle if required is provided by software processing, which is less expensive than providing this functionality by moving the entire projection system.

Any system "washout" (i.e. movements which the occupant should not perceive- for example returning the motion simulator to a neutral position following a motion cue) are computer managed such that the display moves with the motion simulator and / or yaw table.

Preferably, the vehicle simulator comprises at least a part of a vehicle mounted to the simulator platform. As an alternative to being mounted to the static part of the yaw table, the display screen may be provided integral with the platform- e.g. integral with a vehicle cabin. The display screen may be provided in place of, or directly exterior to, the cabin windows. Although in this embodiment the yaw table and the motion simulator must move the display equipment, it is more compact and lighter than e.g. a projection dome.

Preferably the linear motion assembly is constrained to move along a predetermined path only such that the static part of the yaw table motion assembly is constrained to only move along the path. Preferably, the linear motion assembly is a one degree of freedom linear motion assembly such that the static part of the yaw table motion assembly is constrained in all degrees of freedom other than the one degree of freedom- i.e. it can only move along a straight line.

Preferably, the motion simulator is at least partially nested within the yaw table motion assembly. Advantageously, this makes for a more compact arrangement.

According to a second aspect of the invention there is provided a method of simulating vehicle motion, comprising the steps of:

providing at least part of a vehicle,

providing a display screen visible from the at least part of a vehicle,

displaying an image on the display screen,

simulating one of a vehicle surge and sway motion by moving the at least part of a vehicle in a first linear direction,

rotating the vehicle about a yaw axis, relative to the display screen,

rotating the image on the display screen with the at least part of the vehicle about the yaw axis, relative to the display screen,

simulating the other of the vehicle surge and sway motion by moving the at least part of a vehicle in the first linear direction. Preferably, the step of rotating the vehicle comprises the step of accelerating & decelerating the at least part of a vehicle at less than the maximum limit of occupant perception, such that this motion is not detectable by the driver. An example vehicle simulator will now be described with reference to the accompanying figure in which:-

FIGURE 1 is a perspective view of a driving simulator in accordance with the present invention.

There is provided a driving simulator 100 comprising a slide rail assembly 102, a yaw table assembly 104, a hexapod 106, a vehicle cabin 108, and an image projection assembly 110. Referring to the driving simulator 100 as a whole, global axes XG, YG and ZG are defined.

The slide rail assembly 102 comprises a static part in the form of a base 112 which is mounted on the floor (or another static, solid, flat horizontal surface). The base 112 is generally rectangular in shape and comprises first and second parallel guide rails 114, 116. End buffers 118 are provided at the end of each rail in order to arrest motion if required.

The slide rail assembly 102 comprises a moveable part in the form of a moveable carriage 120. The carriage 120 (most of which is obscured in Figure 1) is configured for sliding motion along the respective guide rails 114, 116. An actuation assembly 122 is provided between the guide rails 114, 116 and is arranged to urge the carriage 120 in direction S, parallel to the global axis XG, on the guide rails 114, 116 as required.

The yaw table assembly 104 comprises a static part 124 and a moveable part 126. The static part comprises a circular recess 125, extending from an opening in an otherwise generally planar upper surface 123. The moveable part 126 is mounted for rotation about a yaw axis B, parallel to the global axis ZG, within the static part 124, and more particularly is mounted for rotation within the recess 125. The rotation of the movable part 126 is achieved by an appropriate actuation system in the yaw table 104. A slip ring (not visible) is provided between the static part 124 and the moveable part 126 in order to permit data and power transmission therebetween without inhibiting the extent of rotation.

The hexapod 106 comprises a base 128 above which a platform 130 is mounted. The platform 130 is mounted to the base 128 via a hexapod actuation assembly 132 which is generally known in the art. The hexapod 106 comprises six direct drive torque motors driving six push-pull rods connected to the platform. The actuators move the platform 130 in three rotational and three translational degrees of freedom relative to the base 128. A vehicle cabin 108 is provided which generally comprises part of a vehicle and includes a seat, a dashboard with driving controls and other surrounding equipment in order to provide a realistic driving environment for a driver. The cabin has a local coordinate system XL, YL, ZL which moves with the cabin 108. XL is the direction of travel (surge), YL is side-to-side (sway), and ZL is vertical with respect to the cabin 108 (heave).

The projection assembly 110 comprises a dome 134 which is a concave structure defining an interior volume and having an internal projection screen 136 arranged to completely surround the driver in use. Various projectors 138 are provided which are configured to project an image of the environment surrounding the vehicle onto the screen 136. The projection system is configured to project either a static image (i.e. aligned to the global coordinate system) or to project an image which can move with the yaw table- i.e. rotate about the yaw axis B. The driving simulator 100 is constructed as follows.

The static part 124 of the yaw table assembly 104 is mounted to the carriage 120 of the slide rail assembly 102 such that the static part 124 of the yaw table assembly 104 can only move relative to the base 112 of the slide rail assembly 102 in the direction S.

The base 128 of the hexapod 106 is rigidly attached to the moveable part 126 of the yaw table assembly 104 for rotation about the yaw axis B. The moveable part 126 of the yaw table assembly, and hence the base 128 of the hexapod 106 is constrained in all other degrees of freedom apart from rotation about the axis B.

It will be noted that the hexapod 106 is nested within the recess 125 such that in a neutral position of the hexapod 106 the platform 130 is co-planar with the upper surface 123 of the yaw table 104. Alternatively, the platform 130 may be positioned such that the car body is at the same height relative to the yaw table as it would be above the road. The vehicle cabin 108 is attached to the platform 130 of the hexapod 106 and, as such, can rotate and translate in six degrees of freedom relative to the hexapod base 128.

The projection assembly 110 is attached to the static part 124 of the yaw table assembly 104. As such, in a global sense the projection assembly 110 is only capable of movement in linear direction S (i.e. parallel to XG).

The driving simulator 100 operates as follows.

The normal vibration (high frequency, low amplitude) inputs during driving are provided by the hexapod 106. If an acceleration of longer duration is required then the slide rail assembly can be used as follows.

Should the driver be in a situation within the simulation where he is likely to be changing lanes or undergoing other sway motions of significant amplitude, then the cabin 108 is positioned as shown in Figure 1- i.e. with the direction of travel XL perpendicular to, and the side-to-side axis YL parallel to, slide rail direction S (and XG). The slide rail assembly 102 can be used to provide high amplitude sway motion cues. Should the driver undergo an extended braking or acceleration motion then the vehicle cabin 108 is rotated below the perception level of the driver such that the local forward direction XL is parallel to S, i.e., along the length of the slide rail assembly 102. During the rotation, the image projected on the screen 136 is rotated at the same rate as the cabin 108. In this way, the driver does not notice the rotation.

Naturally, the system can be constantly adjusted such that the cabin 108 is pointing in the appropriate direction for any required long duration acceleration and deceleration motion cues.

Throughout the high amplitude motion cues, and throughout the transition provided by the yaw table 104, the hexapod 106 provides high frequency motion cues to maintain a realistic driving feel.

Variations fall within the scope of the present invention.

The hexapod may comprise six linear actuators instead of direct drive torque motors and push-pull rods.

It is within the scope of the invention to mount the display system:

(i) on the movable part of the yaw table, to move the display system both linearly in one degree of freedom (S) and rotationally in one degree of freedom (B). This means that without image movement, the vehicle occupant will visually perceive only motions arising from movement of the hexapod. Image compensation will be required should visual cues from motion of the yaw table be desired. This will make the yaw table larger in order to provide the additional force required to accelerate the dome.; or,

(ii) on the hexapod. The display system will move with the hexapod platform and vehicle cabin. This means that without image movement, the vehicle occupant will not visually perceive motions arising the hexapod, yaw table or linear motion arrangement. Image compensation will be required should visual cues from motion of the yaw table and / or hexapod be desired. This will make the hexapod and yaw table larger in order to provide the additional force required to accelerate the dome.

Claims

1. A vehicle simulator comprising:

a linear motion assembly having a static part and a moving part;

a yaw table motion assembly having a static part and moving part;

a motion simulator having at least 4 degrees of freedom; and,

a simulator platform;

in which:

the simulator platform is mounted to the motion simulator.

2. A vehicle simulator according to claim 1, in which the motion simulator is a hexapod.

3. A vehicle simulator according to claim 1 or 2, comprising a display screen, in which the display screen is mounted to the static part of the yaw table motion assembly.

4. A vehicle simulator according to any of claims 1 to 3, comprising at least a part of a vehicle mounted to the simulator platform.

5. A vehicle simulator according to claim 4, when dependent upon claims 1 or 2, in which the display screen is integral with the at least part of a vehicle.

6. A vehicle simulator according to any preceding claim in which the linear motion assembly is constrained to move along a predetermined path only such that the static part of the yaw table motion assembly is constrained to only move along the path.

7. A vehicle simulator according to claim 6 in which the path is curved.

8. A vehicle simulator according to claim 6, in which the path is straight.

9. A vehicle simulator according to any preceding claim, in which the motion simulator is at least partially nested within the yaw table motion assembly.

10. A method of simulating vehicle motion, comprising the steps of:

providing a linear motion assembly having a static part and a moving part;

providing a yaw table motion assembly having a static part and moving part; providing a motion simulator having at least 4 degrees of freedom; and, providing a simulator platform;

moving the static part of the yaw table motion assembly using the moving part of the linear motion assembly;

rotating the motion simulator using the moving part of the yaw table motion assembly; and,

moving the simulator platform using the motion simulator.

11.. A method of simulating vehicle motion according to claim 10, comprising the steps of:

providing at least part of a vehicle on the simulator platform;

providing a display screen visible from the at least part of a vehicle;

displaying an image on the display screen;

simulating one of a vehicle surge and sway motion by moving the platform in a first linear direction using the linear motion assembly;

rotating the platform using the yaw table motion assembly, relative to the display screen;

rotating the image on the display screen to match the rotation of the platform; simulating the other of the vehicle surge and sway motion by moving the platform in the first linear direction using the linear motion assembly.

12. A method of simulating vehicle motion according to claim 11, in which the step of rotating the platform comprises the step of accelerating & decelerating the at least part of a vehicle at less than the maximum limit of occupant perception.

13. A method of simulating vehicle motion according to claim 10, comprising the steps of:

providing at least part of a vehicle on the simulator platform;

providing a display screen visible from the at least part of a vehicle;

displaying an image on the display screen;

rotating the platform using the yaw table motion assembly, relative to the static part of the yaw table motion assembly;

simulating the other of the vehicle surge and sway motion by moving the platform in the first linear direction using the linear motion assembly.

14. A vehicle simulator as described herein and in accordance with, or with reference to, the accompanying drawings.

15. A method of simulating vehicle motion as described herein and in accordance with, or with reference to, the accompanying drawings.