KR20010024067A - Motion-imparting apparatus - Google Patents

Abstract

The device for imparting motion to the load includes a means 25 for applying a force to the load and a load support member 27, and means for dynamic change of the support member compliance during operation of the device to optimize power efficiency. 10, 11) are provided. The device is capable of regulating relative motion in a plurality of degrees of freedom between the platform 42 and the reference plane 41, the compliance means 27 supporting the platform weight and the force application means 25 disturbing between the platform and the reference plane. One or more actuators that apply force. The control means 11, 12 adjust the respective actuators 43 to move the actuators in one direction to displace the platform 42 with respect to the reference plane 41. At least part of the support member 27 may be a gas spring and in one embodiment may be in the form of a bellows 45 supporting the platform.

Description

Exercise imparting device {MOTION-IMPARTING APPARATUS}

The present invention relates to a motion imparting device capable of imparting motion for the purpose of adjusting or changing the motion or for selecting an object position. The invention applies to a variety of uses, including positioning devices for manufacturing machines. In general, such machinery does not require a device to perform mechanical operations (such as cutting or deformation) on the material, but rather a device for adjusting the position of a moving object on a low friction bearing system. These machines require precisely stable positioning at high repetition rates and negligible error rates. The use of an electromagnetic ram in such a machine has advantages over other types of actuators because of its simple configuration, zero backlash and zero transfer delay. These valuable properties allow the electromagnetic actuator to move quickly and with great accuracy and reliability. With a positioning accuracy of several microns, a force of more than 20 tons can be applied at several meters per second.

Such devices are also used in training or recreational simulators. In this application, the platform moves relative to the static structure to create a continuous motion feeling to the person riding the capsule fixed to the moving platform. These devices are also used in the testing of suspension systems and stabilizers, and the motion platform is used to produce a corrected disturbance acceleration, so the operation of the stabilizers needs to be tested.

The moving platform of the imparting device is actuated by an actuator unit array or "ram" driven by hydraulic fluid or compressed gas, or ram-like devices electrically operated by means of ball-nut and screw devices. Recently, a device has been designed that uses a low speed crank mounted on a rotating motor or uses electromagnetic interaction between a moving piston type moving member and a cylindrical stator. In the latter electrical and electromagnetic machines, the exercise device needs to be supported against gravity acting on the capsule and the capsule occupant. This is important because otherwise energy will be consumed continuously in the electric machine to create the trust needed to counteract the constant gravity acting on the capsule. This soon heats the motor. This effect is also found in other applications.

One attempt to solve this problem is disclosed in International Patent Application Publication WO93 / 01577. This publication discloses a method for transferring the load of a kinetic platform onto a balancer with a low efficiency spring speed. As a special example, a crank gas spring system is disclosed. The concept of equilibrium of the device built in accordance with WO93 / 01577 does not provide optimum support for the electromagnetic movement base. The present invention is based on the recognition that an adjusted spring (or springset) with a significant spring speed is required for optimal support.

To date, numerous electromagnetic actuators or linear motors have been manufactured. Known machines of various configurations are disclosed in documents such as WO93 / 01646, which disclose electromagnetic devices arranged to operate in cylindrical symmetry, such as in-cylinder piston machines. The main advantage of this type is that the strong attraction between the permanent magnet in the machine and the magnet material surrounding it is balanced around the central axis so that the bearings of the machine do not have to withstand large magnetic forces. A further advantage of the cylindrical configuration is that the magnetic field of the machine is confined within the outer steel case of the actuator or ram and with high efficiency the magnetic field can be arranged to cross the machine's electric coil.

Another advantage of the cylindrical configuration is that the pole of the ram has a sliding seal between it and the inner surface of the ram stator to form the piston of the fluid actuator device. This is advantageous when it is necessary to create a fast acting electromagnetic force that overlaps or ceases with a constant or slow changing force. The latter force is better generated by means of a fluid actuator. Otherwise, the electromagnetic element needs to consume power continuously to provide static or slow changing forces.

In addition, the piston configuration in the cylindrical cylinder is suitable for the application of rams in a number of mountain fish control applications where hydraulic or pneumatic rams are used. This is because the ram's magnetic field is completely confined within the cylinder casing so that the ram can withstand the presence of magnetic dust, which is a problem for cutting debris or electromagnetic linear actuators.

1 is an axial cross-sectional view of an actuator formed as a first embodiment of the present invention.

2 is a schematic diagram of an actuator and control component formed as a first embodiment of the present invention.

3 is a schematic diagram of another actuator control configuration.

4 is a diagram showing another control configuration.

5 is a perspective view of the configuration of the exercise imparting device of the known art.

6 is a perspective view of a configuration of another known exercise providing apparatus.

7 is a perspective view of a motion imparting device formed in accordance with the principles of the present invention.

8 is another perspective view of the present invention.

9 is another perspective view of the present invention.

10 is a schematic diagram of a stewart platform formed as another embodiment of the present invention.

FIG. 11 is a plan view of the platform shown in FIG. 10.

12 is a schematic diagram of FIG. 10 shown in a first operating configuration.

13 is a diagram showing an embodiment in which the reference plane is smaller than the kinetic platform.

14 is a plan view of FIG. 12.

FIG. 15 is a plan view of FIG. 13.

FIG. 16 is a plan view of FIG. 12 with the moving platform displaced to the right.

FIG. 17 is a plan view of the embodiment of FIG. 13 with the motion platform shown to the right with reference to the configuration shown in FIG. 15.

18 is a plan view showing an optimal dimension of a stewart platform formed as an embodiment of the invention.

19 is a three dimensional graph of power consumption of a typical stewart platform imparting device formed as an embodiment of the invention.

20 is a diagram showing how the actuator power demand varies depending on the type of motion.

21A and 21B are diagrams showing a control procedure for an actuator formed as an embodiment of the present invention.

* Code Description

1 ... cylinder 2 ... end face

3 .. Air seal 4a, 4b ... pipe connection

5 ... sealing 6 ... bearing ring

7 ... thrust tube 8 ... piston

9,10 ... valve 11 ... pressure control unit

12 ... electromagnetic force control unit 13 ... position command

14 .. Position feedback signal 15 ... signal

17 ... control line 20,21 ... transducer

25 ... motor 26 ... output element

27 ... pneumatic ram 28 ... means

31 ... Bass Platform 32 ... Exercise Platform

33 ... ram 34 ... hinge

41 ... lower platform 42 ... upper platform

43 ... ram 45 ... support member

51 ... Kinetic Platform 52 .. Base Platform

53 ... ram 54,55 ... radius

56,57 ... Ram

The present invention provides a structure in which the cylindrical stator cavity of an electromagnetic actuator is divided into two parts by a seal on the piston / pole element and comprises means by which the pole assembly acts as a force generating element of the fluid pressure regulation system as part of the gas spring. to provide.

WO93 / 01646 and WO93 / 01577 disclose ram configurations that act in only one direction such that the gas spring of the ram bears the weight against gravity. For this purpose WO 93/01646 discloses a passage configuration in which only one part of the ram cylinder (ie the lower part of the piston) is fluidly connected to the pressurized fluid reservoir formation of the gas spring. In WO93 / 01646 and WO / 9301577 the upper part of the piston is vented directly to atmospheric pressure or to atmospheric pressure through an exhaust storage source.

Each force and force gradient of the gas spring is optimized for the magnitude of the load so that the energy consumed by the device is minimized, using a combination of electromagnetic and air pressure to control the movement of the actuator simulator device more efficiently than WO93 / 01577. I need a way. For this purpose, the gas spring acting under the piston of each ram should not be designed solely for the purpose of supporting the load, as in WO93 / 01577, but a temporary storage source that allows the potential energy from the electromagnetic action of the ram to be stored and recycled after a while. It must function as This energy recycling technology reduces power consumption, improving performance, and reducing the configuration and operating costs of electromagnetic actuators.

The present invention therefore provides a motion imparting system in which a continuous load component is particularly efficiently supported. The so-called motion-base has a shape that is easily adapted to support various types of capsules when applied to the base, is physically stable and alert, capable of generating large pitch angles and rolling motions, and is more accessible for inspection and service. It is a feature of the invention.

According to one aspect of the present invention there is provided an apparatus for imparting motion to a load, which includes means for providing a disturbing force to the load and a support that matches the load, and also allows the power change to conform to the support during operation of the device. Is provided to the means.

In one aspect of the invention the force application means is an electromagnetic actuator. Linear electromagnetic actuators are preferred in many applications, but rotary actuators may be used instead.

The change in compliance can be controlled by the signal generated as an integral of the signal applied to the electromagnetic actuator.

For this purpose, the compliance change is adjusted according to the current required to move the electromagnetic actuator with respect to the load.

The compliance means is a gas spring and the compliance change is achieved by changing the gas contained in the chamber of variable volume.

This change is achieved by adjusting a valve that allows gas to enter or exit the chamber.

Or the support comprises a fluid actuator, in particular a hydraulic actuator, so that its working fluid is directed towards or out of the actuator, thereby changing its compliance.

Compliance changes can be achieved, for example, by adjusting the pressure in each gas spring. In one embodiment this is accomplished by integrating the current drawn by the electromagnetic actuator over time during the movement. By this means, the support means can be optimized so that the electromagnetic ram can be operated within rated ratings and reduce the power consumed by the complete device.

In one embodiment of the invention, including an electromagnetic actuator, the electric machine's stator and stator comprise a piston in the cylinder arrangement, the piston or the stator being shorter than the cylinder or stator and always fully contained therein, the cylinder being end member Both ends are closed, the piston is provided with a rod or thrust member extending through at least one of the end members, an air seal is provided for the end member, and an air seal is also provided for the pole or piston element to provide two cylinders. Wherein the pole comprises a first means for generating a magnetic field pattern comprising at least two poles comprising at least two poles of opposite polarity and a magnetic field arranged to be alternating along the at least a portion of the pole's axial length. The stator has two or more opposite polarities, And second means capable of generating two or more stimulated additional magnetic field patterns arranged alternately along at least a portion of the stator axial length, the second magnetic field pattern being arranged to intersect the first magnetic field pattern Generate axial force.

The physical and electrical parameters of the device are arranged such that the electrical terminals are connected to one or more conventional electronic drive devices that control the phase and amplitude of at least one magnetic field pattern so that the required axial electromagnetic force is generated between the piston and the pole.

Depending on the piston position, two chambers of varying volume within the cylinder contactor, one on each side of the piston, are provided with pipe connections so that the amount of fluid therein can be controlled. This causes the piston to operate simultaneously as an electromagnetic device and a dual action fluid ram.

According to another aspect of the present invention, a compliance means for regulating relative movement in a plurality of degrees of freedom between the platform and the reference plane and supporting platform weight, at least one actuator for applying a disturbance force between the platform and the reference plane, each direction being specified An apparatus is provided comprising an adjusting means for moving in a direction to displace the platform with respect to a reference plane, wherein the compliance of the support means is variable and means for dynamically changing its compliance in accordance with the applied control signal is provided.

In an embodiment formed as a motion-base there are three actuators between the motion platform and the fixed reference plane. The actuator has a pivot or hinge that couples the actuator to a portion that forms a fixed reference plane to confine the actuator motion within each plane. The three planes thus formed intersect along a vertical line connecting the center of the lower triangle formed by the pivot of the actuator to the center point of the moving platform triangle formed by the connection point of the actuator upper end. Since the upper end of the actuator has a joint that provides universal freedom, the choice of three actuator lengths allows the movement platform to have a selected posture within the limits of elevation, pitch and rolling motion. The center of mass of the load lies near and above the center of the moving platform, and the support member is connected in any degree of freedom between the lower fixed triangle center and the upper (movement) triangle, and the compliance of the support member is optimized according to the dimensions of the moving platform. .

In particular, the upper motion triangle formed by the actuator end is smaller than the triangle on the fixture of the device forming the reference plane, which simplifies the problem of limited stroke actuators producing an acceptable motion platform deviation in pitch rolling and securing the capsule to the motion platform. Let's do it.

In particular, the angle between the actuator and the horizontal plane in the operating position of the motor platform is about 45 °. The central support is a simple member or assembly or a pneumatic ram, metal or plastic spring in which the liquid acts on the piston in the actuator and the surface of the liquid away from the piston is compressed by the gas in the reservoir.

Alternatively, the support may be a bellows unit, eliminating the need for universal joints with the stationary and moving platform at the interface of the bellows unit and having the retracted length of the bellows being less than half the extended length. A central support may also be formed from a plurality of compressed gas struts to provide a centering toggle action that eliminates most of the bearing force when the moving platform adopts a minimum height or load position.

In particular, the actuator is an electromagnetic actuator and is designed with sufficient thrust storage capacity to adjust the deviation of the center of mass of the motion platform from the ideal position close to the exact center of the upper motion triangle.

There is a central straight position in which the capsule is continuously returned when the exercise imparting system (hereinafter referred to as the exercise base) is in operation. The occupant of the closed capsule is not aware of this continuous centering action and is carefully adjusted to mix with the background of other movements. Since it takes time to move the capsule in the first location, a lot of energy is required to return the capsule to its initial position, which can be stored in the spring system. In addition, since the center of mass of payload is above the center of the moving platform, there is considerable torque to assist in the rolling or rolling motion suppressed by means such as spring action. Nevertheless, the restoring force generated by the spring should not be too large. Otherwise, a disproportionately large actuator force is required to cause an initial return.

Numerous difficulties arise when attempts have been made to apply the principles of WO93 / 01577 to 6-ram, 6-axis motion platforms (stewart platforms). In particular, if the static load exceeds a certain limit, depending on the height above the center of the moving platform, the device will drop by the combined forward and pitch movements and cannot be returned to the electromagnetic force alone. These defects severely limit payload capability and machine availability.

Therefore, in another aspect, the present invention provides a motion imparting system having six degrees of freedom using six actuators arranged as disclosed by stewart, and the concept disclosed in international patent application WO93 / 01577, namely the weight balance system, Not applied and the force supporting the static load is applied in different efficient ways, greatly reducing the electromagnetic power demand for a given payload actuator, raising the payload limit and improving the dynamic performance of the device.

According to another aspect of the present invention there is provided a device for regulating relative motion in a plurality of degrees of freedom between a motion platform and a reference plane, the device being a means for supporting the weight of the motion platform, an intermittent force between the platform and the reference plane. One or more actuators to apply the control means for controlling the actuator to change the position and direction of the platform relative to the reference plane, characterized in that the movement platform weight bearing means includes a support member associated with each actuator.

In the present invention, in the ideal case of a stewart platform, the three points of the kinetic platform lying on the triangle are six electromagnetic actuators having joints that provide universal freedom at the interface between the actuator and the fixed platform and similar joints between the actuator and the kinetic platform. By selecting six actuator lengths connected to three corresponding points that define a triangle on the part of the device that defines the reference plane, the motion platform can be raised, waved, rocked to the side, rocked to one side, pitched and rolled. By the same movement can be moved to have a variety of directions. The center of mass of Hajun is positioned so that it lies close to the center of the moving platform and the diameter of the moving platform circle has an optimum ratio with respect to the diameter of the reference plane circle. By “circle” of the platform or plane is meant the circumference around the point of attachment to the platform or reference plane at the end of the actuator. Each electromagnetic ram is combined with each spring or assembled on a movement base to act as an output actuator for each spring, which supports the weight (load) of the moving platform in a central linear position.

It is a feature of the present invention that the spring speed is optimized for the power consumption of the device and the force exerted by each spring can be adjusted by the monitoring system to reduce the integration of the associated actuator current to zero over a selected time interval. .

In particular, the upper motion circle is smaller than the corresponding circle on the device fixture forming the reference plane and the ratio of the two radii is chosen to optimize power demand. The optimal ratio of base dimensions is about 1: 1.5.

When all six actuators are in 50% extension, the actual values of both radii are selected so that the angle between the actuator and the horizontal plane is about 45 degrees.

When gas springs are used, when the actuator is fully extended to a closed volume, the ratio of the closed volume of each gas spring system is selected to minimize the operating power consumption of the device when the actuator is fully contracted. Optimum gas spring volume ratio is around 1.8.

In particular, a means of monitoring the current magnitude and direction of each actuator is provided and the pressure in each gas spring is frequently adjusted during operation to maintain the symmetry of the integrated power demand over a selected period of time.

In an embodiment of the invention, the three points of the motion platform are connected to three corresponding points on the device fixture which form the reference plane by means of a connection between the actuator and the reference plane and an actuator having a universal degree of freedom at the connection between the actuator and the motion platform. By selecting three ram lengths, the movement platform can be moved to take any chosen posture within the limitations of the actuator's movement during ridge, pitch, and roll movement. The center of mass of the load is positioned up near the center of the moving platform and has a support member connected in universal freedom between the center of the reference plane and the center of the moving platform. The center of the platform or plane is the center of the triangle formed by three points of connection to three (or six) actuators. The spring speed of the support member is optimized for the parameters of the platform and the load.

In a preferred embodiment the triangle of the actuator connection to the motor platform is smaller than the corresponding triangle on the device fixture forming the reference plane so that the actuator stroke of the proposed stroke creates an acceptable deviation of the upper platform during pitch and roll motion and Simplify the problem of fastening to the motor platform. The ratio of the size of the fixed base platform forming the reference plane to the size of the moving platform is about 1.5: 1.

In particular, when all three actuators are in the linear operating position of the moving platform, the angle between the actuator and the horizontal plane is about 45 degrees.

In particular the central support is a bellows unit. This has the advantage that the upper and lower ends of the bellows can be fixed to a fixed base defining a direct movement platform and a reference plane. The retracted length of the bellows is less than half the extension length, eliminating the need for internal sliding seals. One of the characteristics of the bellows assembly is that it allows vertical movement in the vertical axis direction and the bellows upper end can be inclined at any pitch or roll angle with respect to the lower end, but does not allow side translation (surge or sway) and axial rotational movement. Is not allowed. The bellows assembly can thus function as a gas spring unit and a suppressor.

In particular, the actuator is an electromagnetic ram designed to have sufficient trust storage capacity to accommodate the actual deviation of the center of mass position of the moving platform from the ideal position near the exact center of the upper motion triangle.

The actuator shown in FIG. 1 comprises a piston or pole 8, which moves in a cylinder or stator 1. The piston is connected to a rod or thrust tube 7 which extends through one of the end pieces 2 via an air seal 3. A seal ring 5 is installed on the piston 8 to divide the cylinder into two chambers that are compressed or evacuated through the pipe connections 4a, 4b. The piston is provided with a bearing ring 6 which defines the piston position to smoothly move along the central axis of the device.

The action of the air seal 5 when the port 4 is closed causes the piston to move in the cylinder to compress the gas in one chamber and expand the gas in the other chamber. In either case, a force is generated that returns the piston to the reference position in the absence of power. By regulating the amount of gas enclosed in the two chambers, the force generated by the two springs is predetermined and the reference position is preset by selecting the ratio of the two filling pressures. When it is necessary to reduce the gas spring speed to a low value, the configuration of the end member 2 can be changed to connect an external storage source to each chamber.

Means that can be regulated according to the current drawn by the ram when the pneumatic valve in the line connected to the port 4 is powered by the drive unit for periodic or random positioning of the basin are described below. By providing a facility that continuously adjusts the parameters of the opposing gas spring to the symmetry of the electrical drive current of the ram, it is possible to minimize the power dissipated by the ram.

2, the present invention is applied to an electromagnetic ram. The piston 8 has a seal 5 so that the interior of the cylinder 1 is divided into two chambers A and B. The amount of gas in each chamber is controlled by valves 9 and 10 powered by the pressure control unit 11. The electromagnetic force generated by the ram is controlled by the unit 12 which receives the position command 13 and the position feedback signal 14 from a suitable transducer connected to the ram output rod or thrust tube 7. Unit 12 provides power to the RAM along control line 17. The signal 15 generated by the ram positioning controller 12 is a meaningful process variable on which the pressure control unit 11 acts.

If the ram is used as part of the movement base, the volume of chamber B is maintained at atmospheric pressure. The valve 9 is not shown and the port 4b to the chamber B has a large opening to allow air to communicate freely with the environment. The ram can be configured such that the chamber B is removed by adopting an open end configuration. To achieve a sufficiently low spring rate, chamber A may need to be connected to an external storage source through a wide bore tube. Similar considerations apply to areas such as lifts where the ram is carrying load on the vertical axis.

The control unit 11 increases the amount of gas in the chamber A when the parameter 15 indicates that the current demand by the actuator is mainly consumed in the direction of increasing the volume of the chamber A. It works through). By this means, the pneumatic system reduces the current drawn by the ram to a minimum and increases the efficiency of the system. This arrangement allows random movement sequence by air leak, temperature change, cycle change or ram in one direction. This self compensates for changes in deadload values and moves the RAM to the "park" position at any time. By mathematically analyzing the system, the pressure regulation can find errors in the final equilibrium zone, so the control loop is very stable.

Consider the case where the ram does not receive a constant force (gravity) which tends to reduce the volume of the chamber A. For example, the ram can be used to position inertial loads in repetitive cycles on horizontal tracks with a low coefficient of friction.

The controller 12 is needed to calculate from the position transducer signal 14 the average position of the ram averaged over a period of time within the average or random movement over the entire exercise period. The controller 12 is needed to measure the instantaneous current exposed by the ram and multiply the ram's distance from the calculated average position at that moment. The sum of these "current moments" is transmitted to the valve controller 11 as process variable 15.

When variable 15 indicates that current is mainly consumed in the direction of a force that tends to move the ram to a central position by increasing the volume of chamber A, the controller 11 acts to actuate the gas in chamber A. To increase the amount. The controller 11 reduces the amount of gas in the chamber A if it is indicated that current consumption is predominant in the opposite direction.

The pressure in chamber B is arranged such that the pressure on the two opposing surfaces of the piston 8 is balanced when the ram is at the calculated average position.

In FIG. 2 the system comprises pressure transducers 20, 21 directed from the valve assembly 9, 10 to the line via a low pass filter. The transducer 20 displays the average pressure in the chamber B and the transducer 21 displays the average pressure in the chamber A. The controller 11 acts on the valve 9 such that the pressure 20 multiplied by the piston surface area in the chamber B is equal to the pressure 21 multiplied by the piston surface area in the chamber A. This balance can be more simply achieved using a diaphragm-operated pneumatic controller with a preset ratio of facilities.

An external storage source having the function of reducing the gas spring rate may be connected to the chambers A and B according to the dynamic force profile required for the system.

3 shows the invention applied to a linear electric motor drive that is not built in such a way that air pressure can be applied directly to the drive output. For example, the linear motor may be in an open planar configuration using a permanent magnet shunt suitable for connecting to a three phase servomotor drive unit. In this case the linear motor 25 and the output element 26 are coupled to the compression ram 27 with the piston 8 and the chamber by suitable means 28.

The operating mode is the same. If the load is constant (gravity), chamber B of ram 27 (which forms the output element of the gas spring system) is vented to the atmosphere and the amount of gas in chamber A is adjusted so that the current for the trust in the opposite direction Balance demand If the load is an inertial force, the pressure in one chamber is adjusted to balance the current demand moment around the actuator average position and the pressure in the other chamber is adjusted to balance the force on the piston 8 at the average position of the system.

Figure 4 shows the invention applied to a linear positioning device powered by a rotating motor. In this case a belt drive arrangement is chosen but the invention can be applied to a gear crank drive or a ball screw actuator.

The rotary motor 25 moves the carriage 29 by means of the belt 30. The output element 26 is connected to the gas spring by a connection 28. The operation of the system against gravity or inertial loads has been described above.

The invention is not limited to machines in which all spring forces are provided by gas springs controlled by the unit 11 and valves 9 and 10. Regardless of whether the positioning device is a gas spring or a metal spring, a machine is preferred in which its characteristics are set to provide the energy storage daily report of the device.

The force of all springs required for the full operation of the machine can be provided by a metal or gas spring set to the correct value manually by a skilled person who observes the current drain characteristics for the electric motor adjustment.

In FIG. 5 a fixed or base platform 31 and a moving platform 32 are shown. The ram 33 forms an interconnection between the stationary element and the moving element. By varying the length of the ram, the pose and position of the motor platform can be changed relative to the stationary platform. As each ram expands or contracts, the angle between the ram and the horizontal plane must change. The ram rotates about the lower hinge 34 in a vertical plane.

It is a feature of the present invention that triangles are constructed to take the form shown in FIG. 6 to improve the pitch and roll capabilities of the platform and to improve access to the device for deployment, service and maintenance. In this figure the upper platform 42 is smaller than the lower platform. At the outermost side of the hinge or pivot (which is the mechanical element that holds the highest stress) at the lower end of the ram 43, the main body of the ram is easier to access for assembly, inspection and repair. The surface of the stationary platform is not obstructed by the containment frame, allowing access to the central area if necessary. An additional advantage of this configuration is that the interface area between the kinetic platform and the simulator capsule is reduced, which results in less constraints on the design of the capsule bottom and capsule access.

However, the device shown in FIG. 6 has the disadvantage that the angle between the motion platform 42 and the horizontal plane is greater than the angle between the ram 43 and the horizontal plane in the case of extreme motion, so that the device is locked to the locked position. To prevent this, the relative dimensions of the upper motion platform 42, the lower fixed platform 41 and the length of the ram should be such that no toggle action occurs. In general, the ratio of the size of the fixed platform 41 to the size of the moving platform 42 is reduced. FIG. 7 shows this improvement, with elements having the same reference signs being the same as the embodiment of FIG. 6.

FIG. 8 shows an embodiment with a central vertical support member 45 in which the static load of the moving platform 42 is interrupted to eliminate the need for the electromagnetic ram 43 to generate a continuous force. The vertical spring speed of the central support member needs to be optimized according to the general design of the movement base and the operating parameters. Where the support member is a gas spring actuator it is necessary to communicate with an adjacent compressed gas reservoir of an appropriate volume.

Or a single vertical actuator is replaced or assisted by two or more actuators angled inwards towards the center of the motion triangle and has a ratio such that it rotates at a constant angle in the vertical plane when the motion platform is raised and lowered. Angled actuators may be pre-compressed gas struts arranged to act above the center that may be used to secure the kinetic platform in the loading position when needed.

9 shows an embodiment with a central vertical bellows unit in which the dead load of the moving platform 42 is eliminated, eliminating the need for the electromagnetic ram 43 to generate a continuous force. The vertical spring speed of the central bellows should be optimized according to the design of the movement base and the operating parameters. This means that the flexible part of the bellows can be mounted on the central rigid cornerstone of the selected height (the rigid cornerstone is not shown separately in FIG. 8).

The spring action of the bellows is improved by two or more gas struts (not shown) arranged to rotate at an angle in the vertical plane as the moving platform rises and falls. They can be used to secure the kinetic platform at the load position without the need to depressurize the bellows unit when needed, and can be designed to have an over-centered action that reduces the consumption of compressed air.

The use of the bellows unit as a central containment member does not preclude the connection and mounting of the electromagnetic actuator so that it can act as a gas spring in combination or instead with the force generated by the bellows or gas strut. When an electromagnetic actuator is also used as a gas spring element, it is desirable to provide means for frequently regulating pressure to minimize power consumption by minimizing long term integration of the actuator current.

The exercise imparting device of the present invention consists of a device in which one of the members (base platform) is fixed and the other member (movement platform) is positioned by an actuator.

10 is a schematic diagram of a stewart platform showing the moving platform 51 carried by the ram 53 over the base platform 52. Here the radius 54 of the moving platform circle is smaller than the radius 55 of the base platform. 11 shows this in plan view.

12 and 13 show a stewart platform with radius 54 less than radius 55 and a stewart platform with radius 54 greater than radius 55 (FIG. 13). Consider the force in the gas spring when the kinetic platform surges forward (right in FIG. 6). When the moving platform is less than the base platform, the ram 56 at the "front" of the moving platform is compressed to produce a force that pushes the platform edge upwards, and at the "back" of the platform the ram 57 expands to produce an upward component of the force. And lower the edge of the kinetic platform. This arrangement causes the movement platform to pitch upward during upward surge (FIG. 16). Conversely, the behavior of the device in which the radius of the moving platform is larger than the radius of the base platform will pitch the moving platform downward during forward surge movement (FIG. 17).

Therefore, there should be an optimal configuration between the extremes of surges that does not cause a rise or fall trend. Given a given ram dimension, the optimum ratio of the bottom platform size to the top platform size is 2: 1 as shown in FIG. 18.

19 shows in three dimensions the power consumption of a stewart platform for a combination of six possible movements (raising, surge, sway, pitch, roll and yaw). One axis shows how the power dissipation of the motion base varies with the ratio of the size of the fixed and motion platform, and the other shows how the volume ratio of the gas spring system (or spring constant of the solid spring system) changes.

The best platform size is at 1.5 and the best gas spring ratio is at 1.8. This applies to all types of rams and exercise bases.

FIG. 20 shows how the power demand of the ram varies with the motion and "spring nature" of the device, measured as gas spring ratio. The "balanced" motion base has a large gas spring reservoir and a small volume ratio and is in the left figure and the "hard-spring" motion base is shown on the right. As expected, when the hardness of the spring increases at the edge of the drawing, it jumps in all motions.

Nevertheless, the spring characteristics are optimized for the uplift movement, so the power dissipated by the pitch movement when the device is "balanced" is very large. In addition, when increasing the spring characteristic of the system to an optimum value, the power consumed by the pitch motion can be reduced very much, which is less than when the "hard" spring force is dominant. Other modes of bass motion have similar optimum suspension characteristics, but pitch motion dominates (WO 93/01577 primarily fails in pitch mode). The principles of the present invention apply to a six-axis motion system known as a stewart platform, but equally apply to other motion bases than the three-axis system mentioned in WO93 / 01577.

In a stabilized platform, the simulator device has an equivalent mirror image, and the lower platform is subjected to a motion which is negated by the relative motion of the ram to keep the upper platform static. The optimized motion base device is a stabilized platform based on stewart configuration and the general principle applies to other types of stabilized platforms.

In Fig. 21A, the control sequence of the electromagnetic actuator with the related support whose compliance is variable in order to take into account variable changes such as instantaneous position, required position, load, acceleration, and velocity is shown. In this embodiment the compliance varies with the instantaneous load determined as a function of the current drawn by the electromagnetic actuator in response to the required signal. 21A shows the step after the compliance change of the gas spring. In step 201 the drive current sensed by the sensor is applied as input to the control system. This signal is integrated in step 202 as a rolling integral over a continuous sampling period that is dependent on the particular environment but may be as high as 3 seconds in the case of an entertaining athletic base.

This integration is compared with a predetermined threshold in step 203. Above the threshold regulates the generation of a control signal or "drive pulse" and its length is proportional to the excess. This signal regulates the opening so that the valve enters or discharges gas from a closed chamber of the gas spring in combination with the electromagnetic actuator. This changes the bearing capacity provided to the load by the gas spring by continuously changing or tuning its compliance with the actuator's dynamics. For example, if the actuator expands rapidly, the valve opens and gas enters the chamber, and the amount is increased to reduce the resistance to movement. The "tuning" of the gas spring is chosen such that the gas is released immediately without entering, taking into account the possibility of short-term return movement and the determination of gas introduction or release is calculated over a sufficient time.

In FIG. 21B the displacement driven by the electromagnetic actuator is shown in the main stage in a reciprocating body support system. In the case of a motion base the drive current in the electromagnetic actuator is detected and applied in step 206 but in this case the position of the reciprocating piston or other reciprocating member of the actuator is detected in step 207 and the central data signal is detected in step 209. Is applied). From these signals the current moment around the center position of the moving member is calculated and then the integration of the drive current value is carried out for the time given in step 210, which represents the exact number of cycles of the reciprocating object and the time to prevent interruption of the movement. Indicates.

This integration is compared with a threshold in step 211 and the drive pulse length of the signal is determined in step 212. This signal is applied to one side of the piston, i.e. to the gas pressure rod surface indicated in step 213 and the predetermined ratio is the average pressure value and the pressure is determined in step 214 so that the gas required for the other side of the piston in step 213 Determining the pressure balances the changes introduced into the chamber on the first face of the piston.

Claims (17)

Apparatus for imparting motion to a load provided with means for applying a disturbing force to the load and a load support member and provided with means for dynamically changing the support member compliance during device operation. 2. An actuator according to claim 1, wherein the actuator comprises means for adjusting the position of the load in one or more degrees of freedom and applying a disturbing force to the load to displace it, the support member being capable of exerting the load in addition to the intermittent force. And means for dynamically changing the compliance of said support means acting in a manner related to the force applied to the load to actively displace its displacement. Apparatus according to claim 1 or 2, characterized in that the disturbance force applying means is an electromagnetic actuator. 4. The apparatus of claim 3, wherein the actuator is a linear electromagnetic actuator. The device of claim 3 or 4, wherein the change in compliance is adjusted according to the current required to accelerate the load. 6. The apparatus of any one of claims 3 to 5, wherein the compliance change is controlled by a signal generated as an integral of the piston demand signal applied to the electromagnetic actuator. The device of claim 1, wherein at least part of the compliance means is a gas spring and the compliance change is made by varying the amount of gas contained in the chamber of variable volume. 8. The apparatus of claim 7, wherein at least a portion of the compliance means is a gas spring and a change in compliance is made by adjusting a valve that enters and exits gas into the chamber. The platform weight support means, one or more actuators for applying disturbance forces between the platform and the reference plane, and each actuator to move in one direction, controlling the relative motion in a plurality of degrees of freedom between the platform and the reference plane. An apparatus comprising control means for displacing a platform relative to And wherein the compliance of the support means is variable and means for dynamically changing the compliance in accordance with the input signal is provided. 10. A device according to claim 9, wherein the actuator has a pivot connection in a portion of the device forming a fixed reference plane and each actuator rotates around the pivot connection in each plane. Device according to claim 9 or 10, characterized in that the support member is connected in universal freedom between the moving platform and the reference plane. 12. The apparatus of claim 11, wherein the compliance of the support member is selected in accordance with a parameter of the motion platform. 13. The apparatus of claim 12 wherein the angle between the actuator and the horizontal plane is 45 degrees when the moving platform is in the stationary position. The platform weight support means, one or more actuators for applying disturbance forces between the platform and the reference plane, and each actuator to move in one direction, controlling the relative motion in a plurality of degrees of freedom between the platform and the reference plane. An apparatus comprising control means for varying the position or orientation of a platform relative to Wherein the means for supporting the kinetic platform weight comprises a support member in combination with each actuator. 15. An apparatus according to claim 14, wherein the ratio between the circumferential diameter around the actuator end attachment point to the motion platform to the circumferential diameter around the attachment point of the device portion forming the reference plane around the actuator end is 1: 1.5. . The platform weight support means, one or more actuators for applying disturbance forces between the platform and the reference plane, and each actuator to move in one direction, controlling the relative motion in a plurality of degrees of freedom between the platform and the reference plane. An apparatus comprising control means for varying the position or orientation of a platform relative to And further comprising suppression means for preventing unwanted actuator movement between the movement platform and the reference plane. 17. The device of claim 16, wherein the liquid device comprises a bellows unit.