Patent Publication Number: US-2021166576-A1

Title: Apparatus for simulating motion

Description:
The present invention relates to an apparatus for simulating motion, the apparatus comprising a base, a seat with a seat pan and a seat back, and a mount mounting the seat to the base at least pivotably about a roll axis and a pitch axis of the seat. 
     Apparatuses for simulating motion are used, e.g., in flight simulators for professional training of pilots, in driving or auto racing simulators for training of drivers, or in video gaming, for example together with virtual reality headsets worn by a player. In these applications, the apparatus is connected to a motion simulation controller. 
     Different classes of such motion simulation apparatuses are known. The first and most elaborate class thereof uses a platform, also known as Steward Platform, which is mounted to the base by six jacks (i.e. linear actuators) in a hexapod arrangement. Such platforms usually offer space for two or more seats and provide full six degrees of freedom, i.e. the ability to both shift along and pivot about each of the roll axis, the pitch axis and a yaw axis orthogonal to each other. Simpler systems of this class merely move a single seat and/or offer only fewer degrees of freedom, e.g., only pivoting about the three orthogonal axis. Besides being rather complex and thus expensive, such platforms are limited in dynamics: After each movement, they require a period of re-setting to their home position with a movement sufficiently slow to fall below a person&#39;s motion detection threshold; this re-setting is also known as “washout”. 
     Motion simulation apparatuses of a second class exploit the fact that human brain can be deceived by short, quick movements only giving a cue to acceleration or deceleration, which is interpreted by the brain as being continuous; this principle is known as “motion cueing”. Motion cueing can, e.g., be achieved by slightly pivoting and/or shifting a seat by actuators. This, however, leads to a similar complexity as full-motion systems. Simpler apparatuses of this class merely use inflatable pads in the seat pan and/or in the seat back and, in some cases, controllable tensioners for the seat belts. As the apparatuses of this class move lower masses and require no or only little washout movements, they can be deployed in applications of higher dynamic. However, for achieving more than only rudimental motion cueing, e.g. in different directions, several inflatable pads are to be installed and controlled which increases complexity and cost of such apparatuses. When, on the other hand, the number of inflatable pads is reduced for simplicity reasons, the impression of motion is largely degraded. 
     It is thus an object of the invention to provide an apparatus for simulating motion, which has a simple and robust structure and facilitates a high-grade motion simulation. 
     This object is achieved with an apparatus for simulating motion, comprising: a base; a seat with a seat pan and a seat back, the seat having a roll axis and, orthogonal thereto, a pitch axis; and a mount mounting the seat to the base at least pivotably about said roll axis and said pitch axis; a left seat back flap and a right seat back flap each of which being pivotably attached to a respective side of the seat back; and a linkage linking said seat back flaps to the base so that, when any one of the sides of the seat back is moved towards the base, the respective seat back flap is pivoted inwards and, when said side of the seat back is moved away from the base, said seat back flap is pivoted outwards. 
     The invention is based on the finding that, by linking the seat back flaps to the base, very effective motion cueing is achieved. This is accomplished in a simple and robust way by the proposed seat which is pivotable about said roll axis in longitudinal direction and about said pitch axis in lateral direction and has left and right seat back flaps linked to the base. The left and right seat back flaps may, e.g., be attached to the seat back left and right of the seat back&#39;s center or at the lateral edges thereof. 
     Herein, a movement of a flap towards a person sitting in the seat is denoted as pivoting “inwards,” whereas a movement of a flap away from the person is denoted as pivoting “outwards.” When pivoting inwards, each seat back flap applies a force to the body of the person. This force is perceived by the person as being pressed into the respective side of the seat due to acceleration and enhances the effect of pivoting the seat about the roll and/or the pitch axis. Left and right flaps are moving independently from each other, merely depending on the movement of the respective side of the seat back. However, when the seat back is moved towards the base (or away from it) as a whole, both left and right flaps are pivoted inwards (or outwards, respectively) simultaneously which is perceived by the person as being pressed into the seat. 
     In a preferred embodiment, said linkage comprises a first push rod and a second push rod, each of said first and second push rods having one end coupled to the base and the other end coupled, directly or via a gear, to the respective seat back flap. Thereby, a reliable and simple linkage is achieved which works independently for each side of the seat back. 
     In the embodiment where said other end of each of the first and second push rods is coupled to the respective seat back flap via a gear, it is particularly preferred that the gear comprises a pulley and a link to said seat back flap, the pulley being mounted to the seat back rotatably about an axis parallel to said pitch axis, and each of said link and said other end being eccentrically articulated on the pulley. Such a gear is space-saving, yet reliable. The articulation of said link and said other end on the pulley can be chosen so that force and pivoting angle of the respective seat back flap is adapted to particular requirements. 
     In another advantageous embodiment the seat pan has a left seat pan flap and a right seat pan flap each of which being pivotably attached to a respective side of the seat pan, and a further linkage linking said seat pan flaps to the base so that, when any one of the sides of the seat pan is moved towards the base, the respective seat pan flap is pivoted inwards and, when said side of the seat pan is moved away from the base, said seat back flap is pivoted outwards. With only few additional components, the effect of motion cueing can thereby be further enhanced. 
     In a beneficial variant thereof, said further linkage comprises a third push rod and a forth push rod, each of said third and forth push rods having one end coupled to the base and the other end coupled to the respective seat pan flap. This structure for controlling the pivoting of the seat pan flaps is as simple as it is reliable; similar to the seat back flaps, force and pivoting angle of the respective seat pan flap can be adapted to particular requirements. 
     Favorably, the apparatus comprises a lap belt passed over the seat pan, wherein both ends of the lap belt are attached to the base. It is further advantageous, when the apparatus comprises a left and a right shoulder strap, wherein at least one end of each shoulder strap is attached to the base. Thereby, the effect of tightening and loosening lap belt and/or shoulder straps can be achieved in a simple, yet realistic way. 
     In the embodiment where pulleys are rotatably mounted to the seat back, each of which being a part of a respective gear for linking the left or the right seat back flap to the base, and where the apparatus comprises a left and a right shoulder strap, it is particularly advantageous when one end of each shoulder strap is attached to the circumference of the respective pulley. This facilitates the tightening and loosening of the shoulder straps; in dependence on the size of the pulley&#39;s circumference a transmission ratio between the movement of the seat back relative to the base and the tightening and loosening of the shoulder straps can be achieved. This configuration also reduces the number of attachment points on the base and, consequently, the space required therefor. 
     For easing the process of fastening the lap belt and shoulder straps, it is preferred that, when the apparatus comprises a left and a right shoulder strap, one end of each shoulder strap is coupled to the lap belt. Such coupling can be permanent, e.g., by sewing the shoulder straps on the lap belt, or temporary, e.g., by means of a safety belt lock. 
     According to an advantageous embodiment of the apparatus, the mount comprises a gimbal joint with two degrees of freedom, which gimbal joint mounts a forepart of the seat pan to the base pivotably about said roll axis and said pitch axis. This embodiment is particularly simple. 
     More sophisticated effects of motion cueing can be achieved by an alternative embodiment, where the mount comprises a gimbal joint with two degrees of freedom and a lever, wherein one end of the lever is mounted to the base pivotably about a horizontal axis and wherein the other end of the lever carries said gimbal joint to mount the seat pivotably about said roll axis and said pitch axis. In this embodiment, lifting and lowering of the seat can be achieved independently from pitching, while the overall structure of the apparatus simple and robust. 
     The mount beneficially comprises an elastic element extending between a rear portion of the seat pan and the base. This helps saving energy during operation of the apparatus by compensating for gravitational forces. 
     Preferably, the mount comprises a first and a second actuator for pivoting the seat about said roll axis and said pitch axis. Thereby, external motors or drives for simulating motion are no longer necessary; the apparatus solely has to be connected to and controlled by an external controller. The first and second actuators induce a rolling about the rolling axis and a pitching about the pitch axis together, e.g., in that one of the two actuators induces the rolling and the other one induces the pitching, or in that each actuator is positioned at one of the sides of the seat back or seat pan and the actuators collectively induce both pitching and rolling, i.e. by respective parallel and counter-parallel (antagonistic) operation and by combinations thereof. 
     Particularly preferably, the mount further comprises a third actuator for lifting and lowering the seat, together with said first and second actuators. The first, second and third actuators, thereby, collectively serve to roll the seat about the roll axis, to pitch the seat about the pitch axis and to lift and lower the seat. Controlling these three degrees of freedom together with the seat back flaps and the optional seat pan flaps permits a particularly realistic simulation of motion. 
     Favorably, the mount comprises at least one further elastic element for bringing the seat in a rest position relative to the base. This serves to ease the sitting down and standing up for a person without necessarily actuating and controlling the apparatus already in such a moment. Moreover, the forces needed for bringing the seat into the rest position decrease. 
    
    
     
       The invention shall now be explained in more detail below on the basis of an exemplary embodiment thereof with reference to the accompanying drawings, in which: 
         FIG. 1  shows an example of an apparatus for simulating motion according to the present invention in a partly transparent side view; 
         FIG. 2  shows a portion of the apparatus of  FIG. 1  in a partly transparent back view; 
         FIG. 3  shows a detail of a seat back of the apparatus of  FIG. 1  in a cross sectional view from above; and 
         FIG. 4  shows a portion of the apparatus of  FIG. 1  in a partly transparent view from below. 
     
    
    
       FIGS. 1 to 4  show an example of an apparatus  1  for simulating motion; for better visibility of the apparatus  1  and the components thereof, the views are partly transparent. The apparatus  1 , which can be connected to a motion simulation controller (not shown), comprises a base  2  mounted to or resting on a ground  3 , a seat  4  with a seat pan  5  and a seat back  6 , and a mount  7  which mounts the seat  4  to the base  2 . The seat  4  has a roll axis R in longitudinal direction, a pitch axis P orthogonal thereto in lateral direction, and a yaw axis Y orthogonal to both roll and pitch axis R, P. The mount  7  allows at least pivoting of the seat  4  about said roll axis R and said pitch axis P. Such pivoting includes the movement about both the roll axis R and the pitch axis P simultaneously, which could also be seen as a pivoting movement about a single axis in a plane of both said roll axis R and said pitch axis P. 
     As shown in  FIGS. 1 to 3 , the seat back  6  has a left seat back flap  8  and a right seat back flap  9 . The left seat back flap  8  is pivotably attached to the left side  10  of the seat back  6  and the right seat back flap  9  is pivotably attached to a right side  11  of the seat back  6  by a respective hinge  12 . 
     The seat back flaps  8 ,  9  are linked to the base  2  by a first linkage  13  in a way that, when any one of said sides  10 ,  11  of the seat back  6  is moved towards the base  2 , the respective seat back flap  8 ,  9  is pivoted inwards (arrow Ain) and, when said side  10 ,  11  of the seat back  6  is moved away from the base  2 , said seat back flap  8 ,  9  is pivoted outwards (arrow Aout). In other words, when the left side  10  of the seat back  6  is moved towards the base  2 , the left seat back flap  8  is pivoted inwards and, when the left side  10  of the seat back  6  is moved away from the base  2 , the left seat back flap  8  is pivoted outwards. The same applies to the right seat back flap  9  pivoting inwards and outwards, respectively, when the right side  11  of the seat back  6  is moved towards and away from the base  2 , respectively. 
     In the present example, the seat back flaps  8 ,  9  are located left and right of a center of the seat back  6 , respectively. Alternatively the seat back flaps  8 ,  9  could be located on the lateral edges of the seat back  6 , in a respective opening or recess of the seat back  6 , or elsewhere at the respective sides  10 ,  11  thereof. Moreover, the hinge  12  in this example runs in the direction from top to bottom of the seat back  5   6 ; however, the hinge  12  could alternatively run at an angle thereto, even aslant, when the seat back flaps  8 ,  9  are of suitable shape, e.g. triangular. It is also possible that each seat back flap  8 ,  9  is composed of two or more pieces (not shown). An optional cushion C on the seat back  6  smoothens the  10  seat back  6  and pivoting of the seat back flaps  8 ,  9 . 
     In this example, said first linkage  13  comprises a first push rod  14  and a second push rod  15 . Each of said first and second push rods  14 ,  15  have one end  14   1 ,  15   1  coupled to the base  2  and the other end  14   2 ,  15   2  coupled to the respective seat back flap  8 ,  9 . Such coupling can be achieved, e.g., by respective ball joints or the like. Alternatively, said one ends  14   1 ,  15   1  of the first and second push rods  14 ,  15  could be combined into a single end (not shown) which is coupled to the base  2 , in which case the first and second push rods  14 ,  15  together form a substantially Y-shaped element. 
     Said other end  14   2 ,  15   2  of each push rod  14 ,  15  can be coupled directly to the respective seat back flap  8 ,  9 . Optionally as in this example, however, said other end  14   2 ,  15   2  of each push rod  14 ,  15  is coupled to the respective seat back flap  8 ,  9  via a respective gear  16 ,  17 , i.e. a left gear  16  for the left seat back flap  8  and a right gear  17  for the right seat back flap  9 . 
     Each gear  16 ,  17  optionally comprises a pulley  18 ,  19  and a respective link  20 ,  21 . Each link  20 ,  21  links the pulley  18 ,  19  to the respective seat back flap  8 ,  9 . Each pulley  18 ,  19  is mounted to the seat back  6  rotatably about an axis G, which is parallel to said pitch axis P. On each pulley  18 ,  19 , the link  20 ,  21  and said other end  14   2 ,  15   2  of the push rods  14 ,  15  are eccentrically articulated, respectively, i.e. the link  20  and the other end  14   2  of the first push rod  14  are articulated on the pulley  18  at the same distances D 1 , D 2  from the pulley axis G and at an angle a from each other. In alternative embodiments, the angle a could be larger or smaller than shown in this example—it could even be zero—and/or the distances D 1  and D 2  could differ from each other. The gears  16 ,  17  can alternatively be composed of, e.g., deflection levers or the like instead the pulleys  18 ,  19 . 
     As shown in  FIGS. 1 and 4 , the seat pan  5  may optionally have a left seat pan flap  22  and a right seat pan flap  23 , each of which is pivotably attached to a respective side (i.e. the left seat pan flap  22  to the left side  24  and the right seat pan flap  23  to the right side  25 ) of the seat pan  5  by hinges  26 . A second or further linkage  27  links said seat pan flaps  22 ,  23  to the base  2  in a way that, when anyone of the sides  24 ,  25  of the seat pan  5  is moved towards the base  2 , the respective seat pan flap  22 ,  23  is pivoted inwards (towards a person in the seat  4 ) and, when said side  24 ,  25  of the seat pan  5  is moved away from the base  2 , said seat back flap  22 ,  23  is pivoted outwards (away from said person). In one embodiment, this can be achieved in that the second linkage  27  comprises a third push rod  28  and a forth push rod  29 . Each of said third and fourth push rods  28 ,  29  have one end  28   1 ,  29   1  coupled to the base  2  and the other end  28   2 ,  29   2  coupled to the respective seat pan flap  22 ,  23 , i.e. said other end  28   2  of the third push rod  28  is coupled to the left seat pan flap  22  and said other end  29   2  of the fourth push rod  29  is coupled to the right seat pan flap  23 . 
     It shall be understood that each seat pan flap  22 ,  23  may optionally be composed of more than one pivotable element and/or be attached to the lateral edges of the seat pan  5 , in a respective opening or recess of the seat pan  5 , or elsewhere at the respective sides  24 ,  25  thereof. The hinges  26  for pivotably attaching the seat pan flaps  22 ,  23  to the seat pan  5  can alternatively be oriented other than in longitudinal direction of the seat pan  5  (shown in  FIG. 4 ); and all hinges  12  and  26  of the seat back flaps  8 ,  9  and the seat pan flaps  22 ,  23  may be of any type known in the art. Furthermore, the push rods  14 ,  15 ,  28 ,  29  can alternatively be push elements which are not rod-shaped. 
     The apparatus  1  may comprise an optional lap belt  30  which passes over the seat pan  5  and can be attached thereto or to another part of the seat  4 . In the present example, however, both ends  30   1 ,  30   2  of the lap belt  30  are attached to the base  2 . The lap belt  30  may have a safety belt lock (not shown) for at least one of its ends  30   1 ,  30   2  or in the middle. 
     Furthermore, the apparatus  1  of the present example optionally comprises a left shoulder strap  31  and a right shoulder strap  32 . At least one end  31   1 ,  32   1  of each shoulder strap  31 ,  32  may be attached to the base  2 . Alternatively or in addition thereto, one end  31   1 ,  32   1  of each shoulder strap  31 ,  32  can be attached to the circumference  33  of the respective pulley  18 ,  19 , i.e. one end  31   1  of the left shoulder strap  31  to the circumference  33  of the left pulley  18  and one end  32   1  of the right shoulder strap  32  to the circumference  33  of the right pulley  19 . One end  31   1 ,  32   1  of each shoulder strap  31 ,  32  is optionally coupled to the lap belt  30 , e.g. by sewing it to the lap belt  30  or by plugging it into a safety belt lock thereof. 
     The mount  7  can be of different type. In one embodiment, the mount  7  is composed of a hexapod of jacks (not shown), which jacks provide motion cueing in all six degrees of freedom as known in the art. However, different and particularly more simple mounts  7  may be applied, e.g., a mount  7  with three jacks providing motion cueing in three degrees of freedom. In another embodiment, the mount  7  may comprise a gimbal joint with two degrees of freedom, which gimbal joint mounts a forepart  34  of the seat pan  5  to the base  2  (not shown), wherein the seat  4  can be pivoted about the roll axis R and the pitch axis P due to the gimbal joint. 
     In yet another embodiment according to  FIGS. 1 and 4 , the mount  7  comprises a gimbal joint  35  with two degrees of freedom and a lever  36 . One end  36   1  of the lever  36  is mounted to the base  2  pivotably about a horizontal axis H and the other end  36   2  of the lever  36  carries said gimbal joint  35 . The gimbal joint  35  mounts the seat  4  pivotably about said roll axis R and said pitch axis P. As shown in  FIG. 4 , the lever  36  optionally has two arms  36   A ,  36   B . Said one ends  36   1  of the arms  36   A ,  36   B  of the lever  36  are mounted to the base  2 , one below the left side  24  of the seat pan  5  and the other one below the right side  25  of the seat pan  5 , respectively pivotably about said horizontal axis H. The respective other ends  36   2  of the arms  36   A ,  36   B  carry the gimbal joint  35 . 
     As shown in  FIG. 1 , the mount  7  optionally comprises an elastic element  37 , e.g. a spring or a rubber tube, extending between a rear portion  38  of the seat pan  5  and the base  2 . The elastic element  37  can be used in addition or even as an alternative to the aforementioned gimbal joints, i.e. the gimbal joint mounting the forepart  34  of the seat pan  5  to the base  2  or the gimbal joint  35  shown in  FIGS. 1 and 4  carried by the lever  36 . Moreover, the tension of the elastic element  37  can optionally be adjustable. 
     The mount  7  may comprise a first actuator  39  and second actuator  40  for pivoting the seat  4  about said roll axis R and said pitch axis P. In this example, the first and the second actuators  39 ,  40  are equal, each of them mounted to the base  2 ; the first actuator  39  is coupled to the left side  10  of the seat back  6  and the second actuator  40  is coupled to the right side  11  of the seat back  6 . In other embodiments, the first actuator could be coupled to a central part of the seat back  6  for pivoting the seat  4  about the pitch axis P, while the second actuator  40  is coupled to one of the sides  10 ,  11  of the seat back  6  or, e.g., to the upper end of said first actuator  39  for pivoting the seat  4  about the roll axis R. In still another embodiment, the first and the second actuators  39 ,  40  could be coupled to the seat pan  5  instead of the seat back  6 , particularly to the forepart  34  of the seat pan  5 . 
     Here, the mount  7  further comprises an optional third actuator  41 . Together with the first and second actuators  39 ,  40 ,  5  the third actuator  41  enables lifting and lowering the seat  4 . According to  FIG. 4 , the third actuator  41  is coupled to the forepart  34  of the seat pan  5  at a central point  42  thereof. When, in contrast thereto, the first and second actuators  39 ,  40  are coupled to the forepart  34  of the seat pan  5 , the third  10  actuator  41  could be coupled to the rear portion  38  of the seat back  6 . 
     The actuators  39 ,  40 ,  41  can be of any type known in the art, e.g. electrically, hydraulically or pneumatically extendable elements, e.g. linear actuators (“jacks”), as known to the person skilled in the art. Moreover, the first, second and third actuators  39 ,  40 ,  41  could be of different type. One possible embodiment of such actuators  39 ,  40 ,  41  shall now be explained on the basis of the first actuator  39  shown in  FIGS. 1 and 3 . 
     The first actuator  39  comprises an electric motor  43  mounted to the base  2 . The motor  43  has a worm gear  44  attached thereto and a lever  45 , one end  45   1  of which being coupled to an output shaft  46  of the worm gear  44  rotatably about a shaft axis S. The first actuator  39  also comprises a further push rod  47 , one end  47   1  of which being coupled to the other end  45   2  of the lever  45  rotatably about a lever axis L and the other end  47   2  of which being connected to the seat  4 , in the present example, to the seat back  6 , e.g., to the pulley axis G of the left pulley  18 . 
     Optionally, the mount comprises at least one further elastic element  48  which extends between the seat pan  5  or the seat back  6  and the base  2  at one of the respective sides  10 ,  11 ,  24 ,  25  thereof, for bringing the seat  4  in a rest position relative to the base  2  as shown in  FIG. 1 . In this example, there are four such further elastic elements  48 , one of which extending from the left side  24  of the forepart  34  of the seat pan  5  to the base  2 , another one from the left side  10  of the seat back  6  and the remaining ones (not visible in  FIG. 1 ) from the respective right sides  11 ,  25  to the base  2 . 
     The invention is not restricted to these specific embodiments described in detail herein but encompasses all variants, combinations, and modifications thereof that fall within the frame of the appended claims.