Education and demonstration – Vehicle operator instruction or testing – Flight vehicle
Reexamination Certificate
1999-07-02
2001-04-03
Cheng, Joe H. (Department: 3713)
Education and demonstration
Vehicle operator instruction or testing
Flight vehicle
C434S029000, C434S058000, C472S130000
Reexamination Certificate
active
06210164
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a motion simulator comprising a cabin which is supported on the ground by at least three legs that are each pivotable about a horizontal axis, and a pivotal drive for each leg.
Motion simulators are frequently used as flight or drive simulators, for example as a training device in the training of pilots, or else as a game apparatus in the amusement industry. The basic principle of such motion simulators consists of tilting the cabin about a longitudinal axis and/or a transverse axis, in order to utilise gravity for simulating the forces of inertia associated with acceleration, braking or driving through curves. Thus, the cabin must be suspended such that it can perform movements within a certain range in at least two, preferably three or more degrees of freedom.
Commonly used are suspensions employing so-called hexapodes which enable a movement in all six degrees of freedom but have a very complex construction and require a complex control. In addition, these suspensions have the drawback that the hexapodes must be stably anchored in the ground and are relatively bulky, so that a correspondingly large installation area is required and the cabin must have a comparatively large entry height.
EP-B-0 137 870 discloses a motion simulator of the type indicated above, in which the cabin is suspended at three legs having a T-shaped configuration in plan view. Each leg is configured as a pair of scissors and has a substantially vertical arm which is supported on the ground and the upper end of which is connected through a substantially horizontal hinge axis with a substantially horizontal arm the free end of which is again pivotally connected to the cabin. A drive cylinder serving as pivotal drive is associated with each leg, so that the opening angle of the scissors and hence the height of the corresponding pivotal joint of the cabin above the ground can be varied. Thus, three degrees of freedom are made possible, namely rotations about the longitudinal axis and the transverse axis as well as translations in vertical direction. Although this construction permits to lower the cabin in order to reduce the entry height, it has the drawback that a relatively complex construction of pivotal joints is required. In addition, the movements of the two legs opposing each other must be coordinated such that the pivotal axis of the third leg always maintains its orientation in spcae. This requires a complex control. Since the pivotal axes of the three legs are always in parallel with the bottom surface and, in addition, the two parallel pivotal axes of the legs that are opposing each other are always perpendicular to the pivotal axis of the third leg, the cabin cannot make translational movement in the horizontal plane.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a motion simulator of the type indicated above which has a simple construction, can be controlled easily and nevertheless permits a realistic simulation of motion.
According to the solution, each leg carries a wheel with which it rolls on the ground.
When the cabin of the motion simulator according to the invention is to be lowered at one of the three supporting points, it is only necessary to appropriately pivot the leg connected to this supporting point relative to the cabin, with its wheel rolling on the ground. Then, the entire motion simulator makes a tilting movement about the axis which is defined by the contact points of the two other wheels with the ground. Thus, by pivoting the three legs, a movement in three degrees of freedom is possible. These degrees of freedom which are defined by the pivotal angles of each leg relative to the cabin can be varied completely independently from one another, so that a very simple and robust control is made possible. The articulated connections between the cabin and the legs need not be ball joints or universal joints but can simply be formed by hinges, so that a very simple and robust construction of the motion simulator is achieved.
When all three legs are brought into an approximately horizontal position, the cabin is lowered almost to the ground, so that a very low entry height is achieved and, accordingly, no ladders or the like are needed for entering into or exiting out of the cabin. By synchronously pivoting all three legs, the cabin can be moved in vertical direction, so that short term vertical accelerations such as, for example, road bumps or the like can also be simulated.
During the simulation of motion, the cabin is normally in a lifted position above the ground. Since, when the cabin is tilted by varying one degree of freedom, the pivotal axis is on ground level, such pivotal movement of the cabin is also accompanied by a slight translation in horizontal direction. This is very favourable for creating a realistic feeling of motion.
Another advantage of the invention consists of the fact that the motion simulator need not be rigidly anchored in the ground but can easily be installed on any horizontal ground surface.
Another solution is based on the same function principle and differs from the solution described above only in that one of the legs is stationarily supported on the ground through a disc shaped foot whereas the other legs are provided with self-steering roll assemblies, so that they may roll on the ground in any direction. In this context, the term “self-steering roll assembly” means any suitable arrangement which is capable on rolling on the ground in any direction and wherein the axes of rotation of the roll bodies (wheels or balls) adjust themselves in accordance with the respective direction of movement of the lower end of the associated leg. For example, the self-steering roll assembly may be formed by a single trailing roller or by a set of several trailing rollers. As an alternative, the roll body may be formed by a ball that is mounted to be rotatable in all directions.
While, in the embodiment according to claim
1
, the center of mass of the motion simulator always remains above the same point on the ground and all legs move relative to the projection of the center of mass onto the ground surface, the disc shaped foot remains stationary in the embodiment according to claim
4
, and the other legs move relative to this disc shaped foot.
Useful details of the invention are specified in the dependent claims.
Preferably, the pivotal axis of each leg is non-parallel with the pivotal axis of both other legs. As a result, the directions in which the wheels mounted to the three legs roll are also different from one another, so that the motion simulator cannot be displaced in any direction on the ground, as long as all three wheels are in contact with the ground.
Thus, even in operation, a “shifting” of the motion simulator is avoided. In a particularly preferred embodiment the three legs are mounted to the cabin in a star-shaped manner in angular intervals of 120°.
The wheels may have rubber tires, so that a slip-free support on the ground is assured and at the same time a certain attenuation if vibrations is achieved.
The pivotal drives for the legs are preferably formed by drive cylinders that are articulated between the cabin and the respective leg. Alternatively or additionally, drives for the wheels of the three legs may be provided as pivotal drives.
By means of sensors which detect the position of each leg relative to the cabin and may for example be integrated in the pivotal drives, it is possible at any time to detect the actual posture of the cabin in space in real time, so that the control receives a feedback on the changes of posture that have been effected. Alternatively or additionally it is possible to detect the orientation of the cabin by means of a gravity sensor or by satellite goniometry. The height of the cabin over ground can for example be monitored by means of an ultrasonic distance meter Finally, it is also possible to detect all data on the posture in space by means of a GPS system.
REFERENCES:
patent: 3196557 (1965-07-01), Davidsen et al.
patent: 3829988 (1974
Cheng Joe H.
Goldberg Richard M.
LandOfFree
Motion simulator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motion simulator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motion simulator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2554651