Motion generator

Abstract

The present invention provides a motion generator including an effector for applying forces, moments, and motion to a payload relative to a surface. Each strut is connected at one end to the effector by a first joint and at its other end to an associated rocker by a second joint. The rocker has a pivot axis such that movement of the rocker about the pivot axis causes movement of the effector, and a force applied to the associated rocker causes a force applied to the effector. Movement of the rocker and the force applied by the rocker are controlled by an actuator. The actuator is positioned to apply a force to a point on the associated rocker that is directed away from the rocker's pivot axis. The present invention also relates to a motion system, a driving simulator including the motion generator, and methods of using the motion generator and system.

Description

Technical Field

[0001] The present invention relates to the field of motion systems, particularly for simulating movements such as driving or flying. In particular, although not exclusively, the present invention relates to motion generators, motion systems including such motion generators, methods of using motion generators, motion systems for use, for example, as driving simulators, and methods of producing them.

Background Art

[0002] A motion generator is a device that can move, apply forces and accelerations to a payload in one or more directions or degrees of freedom. The payload can be, for example, a human being undergoing an experience simulated in a motion simulator incorporating the motion generator. Alternatively, the payload can be another motion generator said to be in series with the first motion generator. Motion generators are used in motion systems. The motion system includes a control system for controlling the motion generator.

[0003] The motion system is used in a motion simulator. The motion system is used in various applications including motion simulation (e.g., flight simulators, vehicle and driving simulators), robotics, 3D printing, vibration, and earthquake simulation. The most common type of motion system currently used in motion simulation is the Stewart platform (or "hexapod") motion generator. This is a type of parallel manipulator having six actuators, usually mounted in pairs at three positions on the bottom of the platform and intersecting at three attachment points on the platform or upper plate (or "end effector"). A payload, such as a human user placed on the device or platform, can typically be moved in six degrees of freedom, i.e., three linear motions x, y, z (lateral, longitudinal, and vertical) and three rotations (pitch, roll, and yaw), in some form of cockpit, driving area, or model vehicle, such that a freely suspended object can move. Generally speaking, in a parallel manipulator, several computer-controlled actuators are arranged to operate in parallel to support the payload. In this context, "parallel" means that only one actuator exists within each separate load path between the payload and the bottom. On the other hand, in a serial manipulator, one or more of the possible load paths between the payload and the bottom includes at least two actuators.

[0004] A motion simulator is a simulation system that incorporates at least one motion generator capable of generating the effects or sensations of being in a moving vehicle for an occupant. Motion simulators are specifically used to train drivers and pilots in the form of driving simulators and flight simulators, respectively. They are also industrially used in the manufacture, design, and testing of vehicles themselves, as well as in the design of vehicle components. Specialized motion simulators used for driving and flight simulations typically synchronize visual display devices provided, for example, by a projection system and associated screens and audio signals, with the movement of the carrier (or chassis) occupied by the driver or pilot to provide a better sense of the motion effect. The emergence of virtual reality (VR)-type head-mounted display devices (HMDs) enables immersive simulation modes to be achieved at a lower cost using current motion systems and makes it possible to distribute virtual reality applications for leisure use. Such applications include passive drives in amusement parks or arcades, rides or flights from the perspective of the person themselves, or active games where one or more players exert some control over a driving, riding, flying, or first-person perspective gaming experience. The payload of the motion generator used in motion simulation, such as the chassis or cockpit, etc., is often relatively heavy, about 100 kg. In the motion simulation applications of the motion generator, in many cases, it is necessary to precisely control such a relatively heavy payload over a large movement of about 1 meter or more.

[0005] The types of hexapods commonly used for motion simulations for human participants typically have a relatively narrow bandwidth up to about 20 Hz. This means that they can create oscillatory movements and vibrations of consistent amplitude at a frequency of up to 20 times per second, and beyond this, the amplitude of the motion decreases as the frequency increases. This is sufficient to replicate the movement of most car suspensions, but does not convey the frequency content associated with engine vibrations, tire vibrations, road noise, and sharp curves on a race track. Also, the narrow bandwidth means that the signal is delayed, i.e., the driver cannot respond as quickly.

[0006] Current motion systems, especially those intended for high-specification use such as military and commercial flight guidance and training applications, are typically very large, heavy, complex, and very expensive. Their complexity requires extensive programming and maintenance, further increasing the cost to the user.

[0007] Dedicated driving simulator motion systems have been developed by groups such as McLaren / MTS, Williams / ABD, and Ansible, but these tend to be very mechanically complex and thus expensive, featuring precision-machined custom parts such as expensive linear motors. These dedicated driving simulator motion systems are faster to respond than hexapods when moving in one direction, but are still limited otherwise. Using ball screws in such systems is advantageous in establishing position but disadvantageous in that it blocks force transmission and can achieve only a narrower bandwidth. This results in a less natural motion simulation experience for the human user.

[0008] The motion simulator disclosed in Patent Document 1 includes a mechanism for controlling movements in pitching, heaving, and rolling, using a three-degree-of-freedom parallel manipulator including three upright arms driven by a bell crank. Therefore, it is responsive in those degrees of freedom and has a wide bandwidth. A rotating table rotationally driven by a linear actuator is required to impart yawing. The motion simulator is intended to be relatively small. However, its horizontal degree of freedom is provided by a serial manipulator that introduces compliance, inertia, and friction that limit the responsiveness and bandwidth of the system in the horizontal degree of freedom.

[0009] Patent Document 2 discloses an interactive racing car simulator. The interactive racing car simulator includes a primary motion generator including a simple arrangement of stacking rectangular frames called "X frame and Y frame" that are arranged to move on linear guides in the X direction and the Y direction respectively under pneumatic control. The simple arrangement of frames of the type disclosed in this document provides a good movable range in the X direction and the Y direction, but since the frames are stacked on top of each other in the motion generator, it is not particularly small in the vertical dimension. Furthermore, the movements in the X direction and the Y direction are not particularly accurate, and the simulator will have a relatively narrow bandwidth.

[0010] An example of a primary motion generator for use in a driving simulator is described in Patent Document 3. This specification discloses a 3-degree-of-freedom motion generator in series with a 6-degree-of-freedom motion generator that can maintain large movements in the horizontal plane using the primary motion generator and simultaneously achieve the maximum vertical movement of the secondary motion generator. Thus, the two series-connected motion generators can achieve combinations of movements with different degrees of freedom that are impossible with hexapods of similar size. However, the hexapod described in that specification uses linear actuators, particularly re-rotating ball screw-driven linear actuators. As described above, the re-rotation of ball screw actuators has significant friction, thus degrading responsiveness and bandwidth. The use of other linear actuators in the hexapod structure poses further problems. When the linear actuator is movable as part of a movable strut, it has a high movable mass that causes mechanical resonance at low frequencies, limiting the responsiveness and bandwidth of the system. When the linear actuator is fixed to the bottom and one end of the strut of the hexapod translates along the linear actuator, the weight and inertial load of the system act through linear bearings that also involve significant friction.

[0011] Patent Document 4 discloses a motion system including a platform of cable / actuator control that is slidable on a large low-friction fixed base and enables large horizontal movement of the platform. The cables and actuators are arranged around the large base to enable large horizontal movement of the platform. A secondary motion generator based on a hexapod is then mounted on the platform to support a model cockpit to provide other movements of the cockpit.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

[0013] An object of the present invention is to provide an improved motion generator, particularly useful for simulating driving and various types of vehicle motion, and an improved motion system incorporating such a motion generator, which is more particularly suitable for these applications. [Means for Solving the Problems]

[0014] According to a first aspect of the present invention, there is provided a motion generator comprising an effector for applying force, moment, and movement to a payload with respect to a surface. The motion generator has the effector connected to one or more elongated rigid struts, each strut being connected at one end to the effector by a first joint and at the other end to an associated rocker (i.e., the rocker to which a particular strut is connected) by a second joint. The rocker has a pivot axis, and movement of the rocker about the pivot axis causes movement of the effector, and a force applied to the rocker causes a force to be applied to the effector. The movement of the rocker and the force applied by the rocker are controlled by an actuator, which is formed as an elongated belt, cable, rope drive, or linear motor and is arranged to apply a force away from the pivot axis of the rocker to a point on the rocker.

[0015] According to a second aspect of the present invention, there is provided a motion generator including an effector for applying forces, moments, and motions to a payload relative to a surface. The motion generator has the effector connected to four or more elongate rigid struts, each strut being connected at one end to the effector by a first joint and at the other end to an associated rocker (i.e., the rocker to which a particular strut is connected) by a second joint, the rocker having a pivot axis, the motion of the rocker causing the motion of the effector and the force applied to the rocker causing the force applied to the effector, the motion of the rocker and the force applied by the rocker being controlled by an actuator, the actuator being arranged to apply a force away from the pivot axis of the rocker to a point on the rocker.

[0016] The surface can generally be planar. For example, in many applications, the surface can be the floor of a building in which a motion generator according to any aspect of the present invention is installed, but can be a plinth for the motion generator. In other situations such as the combinations described below and where the secondary motion generator is a motion generator according to the present invention, the surface can be a reference plane above the physical surface on which the combination is installed, typically provided or defined by the primary motion generator. The surface can move with the primary motion generator.

[0017] In this context, a rocker means a solid body attached to one end of an elongated outer joint or pivot, and the body is rotatable about the axis of rotation provided by this joint or pivot, thereby being rotatable relative to another solid body attached to the other end of the joint. Also, a rocker typically has other joints and pick-up points on its body and will be attached to other movable components. Rockers are typically used in mechanical systems to control the relative movement of movable components, control mechanical advantages, and change the direction of movement. Mechanical components such as bell cranks and levers are formed as rockers. For example, rockers are often used in the suspension of automobiles, such as push rod or pull rod suspension devices. Also, for the purposes of the present disclosure, the term "rocker" includes a solid body attached to or integrated with a bent portion, so that the body can describe an arc around an imaginary axis that generally extends upward at the midpoint on the bent portion, and that imaginary axis is equivalent to the axis of rotation as mentioned above for other rockers.

[0018] Thus, the present invention provides a motion generator formed as a parallel manipulator having a total of 1 to 5, or preferably 6 degrees of freedom, and this motion generator includes 1, 2, 3, 4, or more, typically 6 actuators, each of which can generate responsiveness and wide-bandwidth movement. Therefore, the motion generator of the present invention can provide responsiveness and wide-bandwidth movement in all of the total 6 degrees of freedom.

[0019] The motion generator according to any aspect of the present invention can have advantages in some or all of several aspects compared to known motion generators. It can have a low level of friction within the movable part. The design of the motion generator of the present invention minimizes friction and thus, due to the rocker (typically, together with its rotary bearing) having less friction than the linear bearings or linear induction devices used in conventional designs, the weight and load applied to the payload act, making it responsive and having a wide bandwidth. It can have a low inertia due to the low mass of the movable components compared to known designs. It can have a wide bandwidth typically better than 50 Hz with more than one degree of freedom. In some embodiments, in multiple degrees of freedom, for example, 80 Hz, 90 Hz, or 100 Hz or more, it can have a significantly wider bandwidth than 50 Hz, which is a considerable advantage over designs of motion generators of equivalent price. Another advantage of the motion generator according to the present invention is that it can be relatively small in the vertical direction compared to some current motion generator designs. Further, for example, the precision-machined metal bottom required by the motion generator of Patent Document 3 is not required as it can be installed on a conventional building floor.

[0020] Both the first and second joints in the motion generator of the present invention can together have a total number of degrees of freedom of at least 5. One of the first or second joints can include a universal joint, a Cardan joint, a spherical joint, or a flexure, and the other can be a spherical joint.

[0021] A motion generator according to any aspect of the present invention typically includes a plurality of rockers. In most devices, the motion generator can include six rockers. The pivot axis of at least one, preferably each, rocker can be fixed relative to a surface whose surface is the physical surface on which the motion generator is installed. Alternatively, (typically in the context of a combination including a motion generator according to the present invention, which is attached as a secondary motion generator on a primary motion generator), the pivot axis of the rocker cannot be fixed relative to its surface and is fixed relative to a plane above the physical surface, i.e., a plane that moves with the primary motion generator. The rocker pivot can be an external rotating joint, a shaft with bearings, or a flexure. Each rocker can move parallel to the surface. Alternatively, at least one, preferably each, rocker can be inclined at an angle greater than 0 degrees relative to the surface. For example, at least one, preferably each, rocker can rotate about a pivot axis inclined at an angle of 0 to 90 degrees, preferably about 45 degrees (e.g., 40 to 50 degrees) relative to the surface. Some or all of the rockers can form an obtuse angle with the struts to which they are connected. This can reduce the resonance of the motion generator. Additionally, or alternatively, this can make the motion generator smaller.

[0022] A motion generator according to any aspect of the present invention can typically include a total of four, five, six, or more elongated struts. For example, the motion generator includes X elongated struts, where X is less than 6, and includes at least one mechanical restraint means for restraining the total number of degrees of freedom Y of the effector, and the total number of degrees of freedom Y of the effector can be Y = 6 - X. Alternatively, it can include six or more elongated struts. Pairs of elongated struts can be arranged on opposite sides of the effector. In a typical embodiment, the motion generator includes three pairs of elongated struts.

[0023] At least one actuator can be arranged so as to be able to act by returning a load to the surface. The actuator can be, for example, an elongated actuator such as a belt, cable or rope drive or a linear motor. Each form of actuator can have its own advantages. For example, an actuator composed of a belt, cable or rope drive can be relatively inexpensive. When the actuator is a linear motor, it can be connected to an associated rocker via a linkage device.

[0024] When the motion generator is powered by an actuator such as an elongated belt, cable, or rope drive, the elongated belt, cable, or rope drive can be actuated by a pulley or capstan. Such a pulley or capstan can be driven by an electric motor or a gear motor.

[0025] When the actuator includes a belt, cable, or rope drive, both ends of the belt, cable or rope drive are attached to an associated rocker, and between two attachment points on the rocker, the belt, cable, or rope drive can form a closed loop. A passive tensioning device including a pulley can be applied to one end or a part of the closed belt, cable or rope drive to maintain the tension of the belt, cable or rope drive and adapt its fixed length within the changing geometry of the system. The passive tensioning device including a pulley can adapt to changes in the geometry of the rocker. The other end, or another part, of the belt, cable, or rope drive can be attached to a passive force-applying device that maintains the tension of the belt, cable, or rope drive. The passive force-applying device in this case can be, for example, a spring, a gas strut, or a bungee.

[0026] In a motion generator according to any aspect of the present invention, a passive force applying device can be connected to a rocker, providing assistance such as a static preload or a damping force to an actuator, or supporting the weight of a payload. This assistance can be provided by a passive force applying device such as a spring, a gas strut, or a bungee.

[0027] One or more passive force applying devices are composed of a spring, a gas strut, a bungee, etc., and can be connected to an effector or a payload, providing other or alternative assistance such as a static preload or a damping force to an actuator.

[0028] At least one rocker and / or actuator can be mounted on or to a surface. Alternatively, or additionally, at least one rocker and / or actuator can be mounted on a frame or other support fixed to the surface.

[0029] The payload supported by the effector can exceed 10 kg, preferably exceed 80 kg, preferably exceed 250 kg, or preferably exceed 500 kg. Typically, in motion simulation applications, the payload can be a vehicle chassis, a cockpit, or a model thereof.

[0030] A motion generator according to any aspect of the present invention can be arranged to operate as a secondary motion generator in series with a primary motion generator. Such a combination of devices including the primary and secondary motion generators can provide a user with a larger range of motion of the payload. For example, the combination can achieve a range of motion of about one meter, which is particularly required in vehicle and simulation applications. Further, such a combination device can be relatively simple and thus enable the use of a cost-effective primary motion generator, and provide motion in, for example, the X and Y directions using only the secondary motion generator that provides more complex motion. Alternatively, the primary motion generator can have degrees of freedom in X, Y, and yaw. An example of a known motion generator suitable for use as a primary motion generator using the motion generator according to the present invention as a secondary motion generator is disclosed in Patent Document 4. In such a combination, the motion generator according to the present invention is arranged as a secondary motion generator in which at least one rocker and / or an actuator of the generator is attached to the frame of the primary motion generator, to the end effector, or as a payload. For example, the primary motion generator can include a frame or platform as an end effector, and at least one rocker of the secondary motion generator can be pivotally attached to the frame of the primary motion generator.

[0031] According to another aspect of the present invention, a motion system is provided, the motion system including at least one motion generator according to any aspect of the present invention and a control system. The control system can control the operation of the actuator of at least one motion generator, preferably all of its actuators. The control system can calculate the required position, acceleration, and / or force generated by each actuator and generate the required motion profile.

[0032] According to another aspect of the present invention, a driving or vehicle simulator is provided. In this case, the driving or vehicle simulator includes a motion generator according to any aspect of the present invention or a motion system according to the present invention, and at least one environmental simulation means selected from visual projection means or visual display means and audio means. The driving or vehicle simulator can include a cockpit or chassis and / or components of the vehicle simulation. The driving or vehicle simulator can include a display device, a virtual reality device, a projection device, software means for modeling a virtual environment, and means for simulating an environment including at least one of a vehicle model.

[0033] Another aspect of the present invention provides a method of manufacturing a motion system including the steps of manufacturing or providing a motion generator according to any aspect of the present invention and connecting a control system to the motion generator.

[0034] Other features of the motion generator, motion system and driving simulator will become apparent from the description and further claims. When referring to devices such as motion generators, motion systems, driving simulators, and specific aspects or embodiments of the present invention, those skilled in the art will understand that other aspects and embodiments of the present invention can be equally applied to such devices. References to such devices according to the present invention can refer to any aspect of the present invention.

[0035] The motion generator, motion system, driving simulator according to the present invention, and their operations and manufacturing are described here by way of example only with reference to FIGS. 1 to 28 of the accompanying drawings.

Brief Description of the Drawings

[0036]

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Mode for Carrying Out the Invention

[0037] In this specification, references to specific directions and positions such as upper or lower refer to the directions or positions shown in the accompanying drawings.

[0038] <Motion system including a motion generator> A motion system 1 including a motion generator 2 according to a first aspect of the present invention is shown in FIGS. 1 to 19. The motion system 1 includes a motion generator 2 mounted on a surface 4, and in this embodiment, supports a vehicle chassis 3 constituting the payload of the motion generator 2 and control means above a frame 5 (as described in connection with FIG. 26, for example). The frame 5 has a generally triangular shape and is made of a lightweight rigid material such as aluminum. Other shapes and types of frames, such as space frames, and other materials are contemplated for use with such frames. In the illustrated embodiment, the chassis 3 is a replica of the cockpit of a racing car. The chassis 3 is supported by pairs of elongated rigid rods or struts 11, 12, 13, 14 and 15, 16, which at their upper ends are connected to the chassis 3 by upper joints 11UJ, 12UJ, 13UJ, 14UJ, 15UJ, and 16UJ, respectively. The elongated rigid rods 11 to 16 can be made of, for example, carbon fiber to reduce resonance. The upper joints 11UJ to 16UJ can be spherical joints, Cardan joints, or universal joints, and / or can include flexures. The lower ends of each of the elongated rods 11 to 16 are connected by lower joints 11LJ, 12LJ, 13LJ, 14LJ, 15LJ, and 16LJ to associated rockers 11R, 12R, 13R, 14R, 15R, 16R, respectively, which are each arranged to pivot inside the triangular frame 5 of the motion generator 2. The lower joints 11LJ to 16LJ can be spherical joints, Cardan joints, or universal joints, and / or can include flexures. For example, linear actuators 11LA to 16LA that can be belt drives, linear motors (a suitable example of which would be the I-Force ironless linear motor by Parker), or actuators of ball screw drives (a suitable example of which would be the PC series actuator by Thomson driven by an AKM2G servo motor by Kollmorgen). Belt drives are preferred. The connection between the rockers 11R to 16R and the linear actuators 11LA to 16LA is shown in more detail in FIGS. 4 to 7.

[0039] The motion generator according to the present invention can be considered to not include the frame 5. In such an apparatus, at least some or all of the rocker and / or actuator can be directly attached onto the surface 4 instead of the frame. Such a motion generator can have the advantage in that the surface can be made more rigid than the frame. The frame has the advantage that it can be used to support the entire motion generator, particularly when used as a secondary motion generator in series with the primary motion generator.

[0040] Figures 4 and 5 show the rocker 16R and the connected components in more detail. The continuous toothed belt B is connected to the rocker 16R via a round component E that reduces wear of the connected belt B. An example of a suitable toothed belt is the Continental Conti® Synchron Chain Carbon Belt. In Figures 4 and 5, the component E is circular. In Figure 6, the corresponding component E is curved. Note that the belt B shown in Figure 6 is simply shown spaced apart from the curved component for clarity, and in reality, the belt will closely conform to the curved component. The toothed belt B is wound around a corresponding drivable toothed electric capstan (designated "C"). A suitable example of an electric capstan would be a Martin synchron belt sprocket driven by an AKM2G servo motor by Kollmorgen. The capstan C operates under the control of a control system (as described, for example, in connection with Figure 26).

[0041] Note that the passive tension component P in the embodiments of FIGS. 4 and 5 is a bungee or spring. In the embodiments shown in FIGS. 6 and 7, the passive tension component is a compression spring. The belt B is wound around a round freely rotating belt pulley shown as P, and this belt pulley is tensioned by a passive tension device PT, and this passive tension device PT applies a preload tension to the belt B connected to the rocker from the connected rockers 11R to 16R. Under the control of the control system, by the movement of one or more of the rockers 11R to 16R driven by the associated belt B and capstan C, the rods or struts 11 to 16 move the chassis 4 to various states with a wide bandwidth of any of the six degrees of freedom, some of which are described below.

[0042] The motion generator 2 is particularly small in the vertical direction. This small size is an advantage when the motion generator is included in a motion system used in a driving simulator.

[0043] In the following description, the positions of the rockers 11R to 16R during use are described in more detail. For the sake of brevity, only the positions of the rockers 11R to 16R are described, and those rockers are identified in the drawings, and in some drawings other components are not numbered. It will be understood by those skilled in the art that other components such as the elongated struts 11 to 16, the belt drive device, and the connected passive tension device are also affected by the movement of the rocket, but this will not be described in detail in the following description in relation to FIGS. 1 to 3 and FIGS. 7 to 17.

[0044] The motion generator 2 is shown using the chassis 3 in a neutral state in FIGS. 1 to 3. In this state, the state of the rocker is as shown in Table 1.

Table 1

[0045] The motion generator is shown using the chassis 3 in the forward and backward rocking forward state in FIGS. 8 and 9. In this state, the state of the rocker is as shown in Table 2. [Table 2]

[0046] The motion generator is shown using the chassis 3 in the left and right rocking leftward state in FIGS. 10 and 11. In this state, the position of the rocker is as shown in Table 3. [Table 3]

[0047] The motion generator is shown using the chassis 3 in the up and down rocking upward state in FIGS. 12 and 13. In this state, the position of the rocker is as shown in Table 4. [Table 4]

[0048] The motion generator is shown using the chassis 3 in the lateral rocking downward to the right state in FIGS. 14 and 15. In this state, the position of the rocker is as shown in Table 5. [Table 5]

[0049] The motion generator is shown using the chassis 3 in the longitudinal rocking downward at the tip state in FIGS. 16 and 17. In this state, the position of the rocker is as shown in Table 6. [Table 6]

[0050] The motion generator is shown using the chassis 3 in the eccentric rocking leftward at the tip state in FIGS. 18 and 19. In this state, the position of the rocker is as shown in Table 7. [Table 7]

[0051] It should be noted that only a limited number of states are described above in relation to the motion generator 2. It will be understood by those skilled in the art that the motion generator 2 can be operated in more states, including but not limited to, backward pitching, rightward rolling, downward heaving, downward leftward swaying, upward pitching of the tip, and rightward pitching of the tip. Further, it will be understood by those skilled in the art that the motion generator 2 can be operated in a plurality of combinations of such states. For example, the motion generator can be operated in a state where upward heaving and leftward pitching of the tip are combined. The motion generator has the advantages of the present invention, including wide bandwidth, low friction, and low inertia, which enhance the accuracy of the movement of the payload and the chassis 3.

[0052] <Control System> FIG. 26 shows a control system 501 for use in controlling the operation of a motion generator according to the present invention. In connection with FIG. 26, the motion generator is referred to as 502, but the control system 501 is applicable to other motion generators, motion systems, and motion simulators described herein. The control system 501 includes a motion control unit 504. The motion control unit 504 preferably executes a computer program in a deterministic or real-time manner and obtains a motion requirement input 505 from a requirement generator such as a simulation environment 503 or a setpoint generator 506. The motion control unit calculates the required position, acceleration, and / or force 507 to be generated by each actuator 509 to generate the required motion profile 505. Further, the control system 501 includes a servo driver 508. The servo driver 508 provides a current 510 that is accurately controlled to drive the actuator 509.

[0053] During operation, the motion control unit sends the required position or force 507 to each servo driver 508. The actuator 509 has a motion measuring device 511 such as an encoder. The motion measuring device 511 optionally provides motion feedback 512 to the motion control unit via the servo driver. The motion control unit compares the required motion profile 505 with the measured one 512 and updates the actuator demand 507 accordingly.

[0054] Also, FIG. 26 shows a control system having a simulation environment 503, where the physics of a simulated vehicle, such as a driving simulation, and its environment, such as a race track or an urban road, are calculated. In this embodiment, the control system 501 receives motion demands from a simulation environment 503 representing the motion of a virtual vehicle. A computer program determines the motion of the vehicle in the virtual world 514 and then applies a motion cuing algorithm 513 (MCA, also known as a washout filter) to convert the simulated vehicle motion into a motion that can be represented by a motion generator. These calculated motions are then provided to the control system as motion demands 505. The MCA 513 can be part of the simulation environment 503 or the control system 501, or separated into both. The simulation environment 503 can receive an input signal 515 from a control device 516. The control device 516 is used by a human user, such as an operator, driver, passenger, or pilot, to control the virtual vehicle within the simulation environment, such as for steering, throttle, or brake inputs. The operator is likely to be a passenger in the motion generator 502. These inputs 515 can be returned to the simulation environment either via the control system or directly. Also, the simulation environment is likely to generate outputs for the driver, passenger, or other user or operator on a visual display device 517. Also, the simulation environment can require additional data 518 from the control system, such as related to the position of the motion generator or the control device input signal.

[0055] <Combination of motion generators> A motion generator according to any aspect of the present invention can be used in series with other motion generators. For example, the motion generator according to the present invention can be used as a secondary motion generator, i.e., the motion generator itself becomes the payload of a primary motion generator. FIG. 27A shows a combination 600. The combination 600 includes a first (or “primary”) motion generator 602 and a second (or “secondary”) motion generator 604 (which is a motion generator according to the present invention) according to the present invention. This combination is typically installed on a planar surface 601 (not shown), which is the building floor surface. The primary motion generator 602 is a simple X and Y frame device. This frame device includes a lower frame 606 including lower frame members 607, 608, and an upper frame 610. The lower frame member 608 supports a motor 612. The motor 612 can be operated under instructions from a control system 605 (as shown, for example, in FIG. 26) to move the frame 610 in the X direction. A similar motor 614 is similarly arranged on the frame 610 and moves the frame in the Y direction under instructions from the control system 605. The secondary motion generator 604 is a motion generator according to the first aspect of the present invention that is attached to the primary motion generator 602, and the secondary motion generator 604 includes a rocker 616 (which is directly attached to the upper frame 610 of the primary motion generator, i.e., attached to a plane above the surface 601). The rocker 616 is drivably connected to an actuator (including a motor 617 and an elongate belt 618 attached to the movable end of the rocker and wound around a capstan 618CA) and an elongate rigid strut 620. The elongate strut 620 is connected at one end by a joint to the free end of the associated rocker 616 and at the other end by a joint to an end effector that supports a payload 619. When the motor 617 is operated under instructions from the control system, it drives the drive capstan 618CA, which then drives the belt 618 to move the associated rocker 616. The rocker 616 pivots about a vertical pivot axis (through the rocker pivot 616P) using a rocker arm that moves in a horizontal arc (shown as A).The movement of the rocker 616 moves the associated strut 620 to move the end effector 618 / payload 619 in the X and Y directions and, similarly, allows for pitching, heaving, and rolling movements. The combination 600, the primary motion generator 602 is relatively inexpensive but provides a good range of movement in the X and Y directions, and the secondary motion generator 604 provides a wider bandwidth, a lower level of inertia, and a lower level of friction, which is an advantage in increasing the accuracy of the movement imparted to the payload.

[0056] <Combination of motion generators> Figure 27B shows another combination 300 according to the present invention. The combination 300 includes a first (or "primary") motion generator 302 and a second (or "secondary") motion generator 304 (which is a motion generator according to the present invention). The combination 300 is installed on a planar surface 301 such as the floor within an operating simulator building. The primary motion generator 302 is generally a simple X and Y frame device, as described above in relation to the primary motion generator 602, and includes a lower frame 306 including lower frame members 307, 308 and an upper frame 310. The lower frame member 308 supports a motor 312, which can be operated under instructions from a control system 305 (as shown, for example, in FIG. 26) to move the frame 310 in the X direction. A similar motor 314 is similarly disposed on the frame 310 and moves that frame in the Y direction under instructions from the control system. The secondary motion generator 304, which is a motion generator according to a second aspect of the present invention, includes six rockers 316A through 316F, each rocker being drivably coupled to an actuator (including motors 317A through 317F and associated splined capstans corresponding to the motors 317A through 317F and associated elongate toothed belts 318A through 318F that wrap around freely moving capstans such as 318CA or 318CB) and an elongate rigid strut (struts 320A through 320F). Each of the elongate rigid struts 320A through 320F is connected at one end by a joint to the free end of the associated rocker 316A through 316F and at the other end by a joint to an end effector (a platform 321 that supports a payload 3322). It should be noted that the rockers 316A through 316F are attached to the upper frame 310 of the primary motion generator 302 in a plane defined by the upper surface of the frame 310 that is spaced above the surface 301.When motors 317A through 317F operate under the command of the control system, they drive the associated belts 318A through 318F, and as a result, the associated rockers 316A through 316F pivot about a horizontal pivot axis using rocker arms that move in an arc (shown as A for rocker 316A, for example). Thus, the movement of rockers 316A through 316F moves the associated struts 320A through 320F, moving the end effector 318 / payload 319 in the X and Y directions and, similarly, enabling pitching, heaving, and rolling movements. The combination 300 has the advantage that the primary motion generator 302 is relatively inexpensive but provides a good range of motion in the X and Y directions, and the secondary motion generator 304 provides a wider bandwidth, a lower level of inertia, and a lower level of friction, which enhances the accuracy of the payload movement.

[0057] <Operation Simulator> The operation simulator 200 according to the present invention is shown in FIG. 20. The operation simulator 200 comprises a motion system 202 including a motion generator 204 according to the present invention, such as described above in relation to FIGS. 1 through 19, or as described below in relation to FIGS. 21 through 23, or a combination as described in relation to FIG. 27B. The motion system 202 is mounted on a surface 206 in front of a projection system 206 capable of displaying an image of the driving environment, and the projection system constitutes an example of environmental simulation means. An audio system (not shown) replicates the sounds of the driving environment and provides sound to the user, constituting another example of environmental simulation means. The motion generator 204 of the operation simulator 200 operates under the command of a control system 207 (as described, for example, in relation to FIG. 26).

[0058] As described in some of the above embodiments, the motion generator according to the present invention is suitable for use in an operating simulator as described in this embodiment, and can be advantageous in some or all of several aspects compared to known motion generators for such applications. First, a) since it acts on the weight and inertial load, use an external rotating joint or rotary bearing rather than a linear bearing, b) eliminate the need for a recirculating ball screw linear actuator, so that it can have a low level of friction within its moving parts. Second, especially when a rotary motor is used rather than a linear motor, especially a linear actuator that moves the whole using struts within the mechanical device can have low inertia. When a linear motor is used as the actuator of the motion generator according to the present invention, only its forcer needs to move, but its stator or magnetic path can remain stationary. Third, it can have a wide bandwidth typically better than 50 Hz and more than one degree of freedom. In some embodiments, it can have a bandwidth significantly wider than 50 Hz, for example, 80 Hz, 90 Hz, 100 Hz, or wider. Also, it should be understood that the motion generator 204 used in the operating simulator 200 can be made particularly small in the vertical direction. This better replicates the height of the vehicle being simulated compared to other motion systems where the user requires a lift / bridge to enter and exit the operating simulator.

[0059] <Motion system including a motion generator> Another motion system 700 according to the present invention is shown in FIG. 21. The motion system 700 includes a motion generator 702 according to the present invention, and the motion generator 702 supports a payload 704 above a surface 706. The motion generator 702 includes four rocker systems 710, 712, 714, and 716 (the rocker systems 714 and 716 are not clear in FIG. 21), which are generally as described above. Linear restraints 720 and 722 are arranged at right angles between the rocker devices 710, 716 and 716, 714, respectively. Also, the motion system 700 includes a control system (as described, for example, in connection with FIG. 26).

[0060] In use, lockers 710 to 714 are moved by the belt drive B, generally as described above, and an elongated strut interposed between the locker and the payload 704 moves the payload in four degrees of freedom with a wide bandwidth. Restraints 720, 722 prevent the payload 704 from moving excessively in the forward and backward and left and right directions, respectively.

[0061] It will be understood by those skilled in the art that the motion system 700, although relatively simple, can provide good performance with respect to bandwidth. The system can have a bandwidth exceeding 50 Hz, or even exceeding 100 Hz, in all degrees of freedom, despite having a primary motion generator with a narrower bandwidth. This is because the secondary motion generator functions highly in this regard.

[0062] <Other motion generators> Another motion generator 400 according to the present invention is shown in FIGS. 22 and 23. The motion generator 400 is configured and arranged generally as described above in connection with the motion generator 2 shown in FIGS. 1 to 19, except that six belt-driven linear actuators 11LA to 16LA are replaced by six linear motors and six link devices, driving the corresponding rocker and strut to move the platform 402 and constituting an effector. The six linear motors are operable to move the platform 402 in six degrees of freedom. FIGS. 22 and 23 show one of the six linear motors 411 in more detail. More specifically, FIG. 22 shows the coil 412 and the magnetic path 414 of the linear motor 411. The linear motor 411 is pivotally connected to an elongated lower strut 418 by a pivot 416. Another pivot 419 connects the strut 418 to a rocker 420. The rocker 420 is mounted for horizontal pivoting to a pivot 421 in parallel above the surface to which the motion generator 400 is attached. The upper strut 422 has its lower end connected to the rocker 420 by a clevis joint 424. The upper strut 422 is then pivotally connected at its upper end to the platform 402 (omitted in FIG. 23 for clarity) by another clevis joint 425 (shown in FIG. 23). In use, the linear motion of the coil (e.g., 412) during operation of the linear motor (e.g., 411), as controlled by a control system (e.g., as described in connection with FIG. 26), moves the struts (e.g., 418, 422) connected to the associated rocker (e.g., 420) to move the platform (402) in six degrees of freedom.

[0063] <Alternative rocker device> An alternative locker device is schematically shown in FIGS. 24 through 25. In this embodiment, the motion generator 100 is mounted on a planar surface generally designated as 102 and supports a chassis 103 that constitutes the payload of the motion generator 102 and control means (not shown) above a triangular frame 105 (explicitly omitted). The chassis 103 is composed of a lightweight rigid material such as aluminum or carbon fiber and is a replica of the cockpit of a racing car. The chassis 103 is supported by pairs of elongated rigid rods or struts 111, 112, 113, 114 and 115, 116, and the pairs of elongated rigid rods or struts are connected to the chassis 103 at their upper ends by upper joints 111UJ, 112UJ, 113UJ, 114UJ, 115UJ and 116UJ, respectively. The elongated rigid rods 111 through 116 can be made of carbon fiber, for example, to reduce resonance. The upper joints 111UJ through 116UJ can be spherical joints, Cardan joints, or universal joints and / or can include flexures. The lower ends of each of the elongated rods 111 through 116 are coupled to rockers 111R, 112R, 113R, 114R, 115R and 116R, respectively, by lower joints 111LJ, 112LJ, 113LJ, 114LJ, 115LJ and 116LJ (and they can be spherical joints, Cardan joints or universal joints and / or can be provided with flexures), and the rockers are arranged to pivot inside the triangular frame 105 of the motion generator 100 and are driven by link devices 111L, 112L, 113L, 114L and 115L, 116L connected to linear actuators 111LA, 112LA, 113LA, 114LA and 115LA, 116LA.

[0064] In contrast to the previous embodiments, when the rocker moves parallel to the surface to which the motion generator is attached, the rockers 111R, 112R, 113R, 114R, 115R and 116R are arranged to pivot at an angle that is non-parallel to the surface (in this case, 102) to which the motion generator is attached, such that the pivot axis for each rocker is perpendicular to the surface. In this description, the opposite end of the rocker with respect to the pivot axis is called the free end. In this embodiment, the rocker is inclined at 45 degrees from the surface (the angle shown as JPEG0007691741000008.jpg1111 between surface 102 and axis A about which rocker 113R pivots is shown in FIG. 25). In other embodiments, the pivot rocker can be inclined from 0 degrees to 45 degrees from the surface. When the surface to which the motion generator is attached is not planar, the inclination angle of the rocker is taken from a reference line. When the motion generator is arranged in combination as a secondary motion generator, the inclination angle of the rocker can be taken from a plane defined above the surface, such as the planar surface of the upper frame of the primary motion generator to which the rocker is attached. Such a plane can be regarded as the "surface". In some situations, such an inclined rocker device is preferred because it can reduce undesirable resonances. Also, the inclined rocker device can be made smaller. Also, the load on which the bearing acts can be reduced, thereby further reducing friction. JPEG0007691741000008.jpg1111 is shown in FIG. 25)

[0065] <Other alternative rocker devices> Figures 28A and 28B show other alternative locker devices suitable for use in a motion generator according to the present invention. Figure 28A shows a locker 400. The locker 400 includes a locker bottom 402 that is connected to a locker arm 406 by a flexure 404. The flexure is formed from a predictable elastic material such as spring steel, tool steel, or a composite such as E-glass or S-glass. The flexure 404 allows for an arcuate movement of the locker arm 406 (shown as arc C) in a plane perpendicular to the flexure 404 that approximates rotation about an imaginary axis through the center of the flexure 404. The locker arm 406 is shown at one position on arc C in Figure 28B. The imaginary axis can be considered equivalent to the pivot axis of the other lockers described above. Such a locker device incorporating a flexure can be advantageous in that it avoids the use of bearings, eliminates backlash, and / or increases rigidity.

[0066] <Method of manufacturing a motion system> A motion system according to the present invention including a motion generator and control means as described above can be assembled from custom and standard components by conventional means. In particular, the motion system can be manufactured by connecting a motion generator according to the present invention to a control system.

Claims

1. A motion generator comprising an effector for applying forces, moments, and motions to a payload relative to a surface in four or more degrees of freedom, wherein the effector is connected to four or more elongate rigid struts, each strut being connected at one end to the effector by a first joint and at the other end to an associated rocker by a second joint, the rocker having a pivot axis, the movement of the rocker about the pivot axis causing movement of the effector and the forces applied to the effector being caused by forces applied to the associated rocker, the movement of the rocker and the forces applied by the rocker being controlled by an actuator, the actuator applying a force away from the pivot axis of the rocker to a point on the associated rocker, the actuator being formed as an elongate belt, cable or rope drive or a linear motor, a motion generator in which the pivot axes of each of the rockers are fixed relative to each other.

2. The motion generator according to claim 1, comprising six struts arranged in three pairs, each one end of the struts being connected to an associated rocker and each other end of the paired struts being connected to three attachment points or joints in the effector.

3. The motion generator according to claim 1, wherein at least one actuator comprises a belt, the belt being attached to the associated rocker at at least one end and applying one or more forces to the rocker.

4. The motion generator according to claim 1, wherein the total number of degrees of freedom of the first joint and the second joint is at least five in both cases.

5. The motion generator according to claim 1, wherein one of the first joint or the second joint includes a universal joint, a Cardan joint, a spherical joint or a flexure, and the other is a spherical joint, a universal joint, a Cardan joint or a flexure in series with an external rotation joint.

6. The motion generator according to claim 1, wherein the motion generator includes a plurality of rockers in which the pivot axis of each of the rockers is fixed relative to the surface.

7. The motion generator according to claim 1, wherein the pivot axis of at least one rocker is inclined with respect to the surface.

8. The motion generator according to claim 7, wherein the pivot axis of at least one rocker is perpendicular to the surface.

9. The motion generator according to claim 1, wherein the rocker forms an obtuse angle with the strut to which it is connected.

10. The motion generator according to claim 1, wherein the motion generator includes five or six elongated struts.

11. The motion generator according to claim 1, wherein at least one actuator includes a long belt, cable or rope drive, and the actuator is operated by a belt pulley or capstan.

12. The motion generator according to claim 11, wherein the actuator includes a belt, cable or rope drive, both ends of the belt, cable or rope drive are attached to the associated rocker, and between two attachment points on the associated rocker, the belt, cable or rope drive forms a closed loop.

13. The motion generator according to claim 12, wherein a passive force applying device including a belt pulley is applied to the closed belt, cable or rope drive to maintain the tension of the belt, cable or rope drive.

14. The motion generator according to claim 1, wherein one end of the belt, cable or rope drive is connected to the associated rocker, and the other end of the belt, cable or rope drive is attached to a passive force applying device for maintaining the tension of the belt, cable or rope drive.

15. The motion generator according to claim 1, wherein the actuator is connected to the associated rocker and includes a link device and a linear motor, and the link device connects the rocker to the linear motor.

16. The motion generator according to claim 15, wherein the link device is composed of an elongated strut of a fixed length and has a joint selected from an external rotating joint, a spherical joint, a universal joint or a Cardan joint and a bent portion at either end.

17. The motion generator according to claim 1, wherein a passive force applying device is connected to a rocker, and the actuator provides assistance to the motion generator.

18. The motion generator according to any one of claims 1 to 17, wherein one or more passive force applying devices, springs, gas struts, or bungees are connected to the effector or the payload to provide assistance to the actuator.

19. The motion generator according to any one of claims 1 to 17, wherein at least one rocker and / or actuator is attached to or fixed to the surface.

20. In a combination including the motion generator according to claim 1, the motion generator is arranged to operate as a secondary motion generator connected in series with a primary motion generator.

21. In the combination according to claim 20, at least one rocker and / or actuator of the secondary motion generator is attached to the end effector or payload of the primary motion generator.

22. In the combination according to claim 20, the actuator of the secondary motion generator is attached to the end effector or payload of the primary motion generator.

23. In the combination according to claim 21, the primary motion generator includes a frame, and at least one of the rockers of the secondary motion generator is pivotally attached to the frame of the primary motion generator.

24. In the combination according to claim 20, the secondary motion generator has six struts.

25. A motion system including at least one motion generator according to claim 1 and a control system.

26. A motion system including at least one combination according to claim 20 and a control system.

27. An operation simulator including the motion generator according to claim 1, the combination according to claim 21, or the motion system according to claim 25 or claim 26, and at least one environmental simulation means selected from visual projection means or visual display means and audio means.

28. In a method of manufacturing a motion generator according to claim 1, the method includes providing an effector suitable for applying forces, moments, and motions to a payload relative to a surface in four or more degrees of freedom, connecting the effector to four or more elongated rigid struts, and connecting each strut at one end to the effector by a first joint and at the other end to a rocker by a second joint, wherein the rocker has a fixed pivot axis and is configured such that movement of the rocker about the pivot axis causes movement of the effector and a force applied to the rocker causes a force applied to the effector, the movement of the rocker and the force applied by the rocker being controlled by an actuator, the actuator applying a force away from the pivot axis of the rocker to a point on the rocker, the actuator being formed as a long belt, cable or rope drive, or a linear motor, and the pivot axes of each rocker being fixed to each other.

29. In a method of manufacturing a motion system according to claim 25 or claim 26, the method includes connecting a control system to the motion generator according to claim 1.

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