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US-12624711-B2 - Method and apparatus for reducing positive pressure of actuating cylinder of universal hinged support

US12624711B2US 12624711 B2US12624711 B2US 12624711B2US-12624711-B2

Abstract

A method and apparatus for reducing a positive pressure of an actuating cylinder of a universal hinged support. An application object is the actuating cylinder of the universal hinged support. The apparatus comprises a foundation, a base frame, a force application apparatus, a direction adaptation apparatus, a universal swing rod apparatus, and an integral external connection apparatus. The method comprises: step 1, determining main design parameters and the type of the force application apparatus; step 2, structural design of the apparatus: designing the structure of the apparatus after the main design parameters and the type of the force application apparatus are determined; and step 3, calculating, testing, and evaluating an actual gravity moment or positive pressure and an effect of weight compensation, determining whether to meet design requirements, and calculating or testing the evaluated gravity moment and a reduction ratio.

Inventors

  • Fangyuan HAN

Assignees

  • Fangyuan HAN

Dates

Publication Date
20260512
Application Date
20210824

Claims (20)

  1. 1 . A method for reducing a positive pressure of an actuating cylinder of a universal hinged support, the method being applied to the actuating cylinder of the universal hinged support, wherein a device used in the method comprises: a base frame, a force application apparatus, a direction adaptation apparatus, a universal swing rod apparatus, and an integral external connection apparatus; wherein, the direction adaptation apparatus is mounted on the base frame; one end of the force application apparatus is connected to the base frame through the direction adaptation apparatus, and the other end of the force application apparatus is connected to the universal swing rod apparatus via an connection apparatus, the integral external connection apparatus is connected to the actuating cylinder; the method comprises: providing a force between the actuating cylinder of the universal hinged support and the base frame using the force application apparatus, to form an anti-gravitational moment and weight compensation.
  2. 2 . The method for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 1 , further comprising: step 1, determining main design parameters and a type of the force application apparatus, comprising: A, determining the main design parameters, wherein the main design parameters comprise an amount of reducing a maximum positive pressure of the actuating cylinder, a maximum gravitational moment and a ratio of gravitational moment to be eliminated therefrom, a maximum anti-gravitational moment, and an amount of weight compensation; B, determining the type and structural form of the force application apparatus: determining the type of the force application apparatus comprising: determining a force application mode used for providing an anti-gravitational moment, wherein the force application mode comprises: a tension spring, a torsion spring, a gravity counterweight, a gravity pendulum, an air spring, or an electromagnetic force, and one of the force application modes or a combination of two or more modes can be selected; determining the structural form, wherein the structural form comprises an open loop structure, a closed loop structure, a semi-open loop structure, a semi-closed loop structure, or a hybrid structure, and one of the structural forms can be selected; the above steps A and B can be performed with no particular orders or be performed simultaneously; step 2, performing structural design for the device: designing a structure of the device after determining the main design parameters and the type of the force application apparatus, comprising: structure designing, manufacturing, assembling, and debugging; wherein the structure designing comprises designing of the base frame, designing of the force application apparatus, designing of the direction adaptation apparatus, and designing of the integral external connection apparatus; and step 3, calculating, testing and evaluating an actual gravitational moment or positive pressure and an effect of weight compensation, determining whether design requirements are met, calculating or testing the evaluated gravitational moment and a reduction ratio thereof, calculating or testing the evaluated weight compensation effect, and stopping, in a case of meeting the design requirements, and taking the obtained design solution as a design result; and in a case of not meeting the requirements, adjusting the parameters, repeating the above steps, and redesigning until it meets the design requirements.
  3. 3 . The method for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 1 , wherein the method comprises designing main parameters of the universal swing rod apparatus, designing a structure of the universal swing rod apparatus, and adjusting and iterating the parameters and structure of the universal swing rod apparatus; and the universal swing rod apparatus is installed on a foundation or at a bottom of the base frame, and the universal swing rod apparatus or a cylinder barrel of the actuating cylinder of the universal hinged support is connected with an opposite end of the force application apparatus through the integral external connection apparatus, so as to form a closed loop.
  4. 4 . The method for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 2 , wherein the step 2 of the method further comprises a process of arranging an axis of a first revolute joint of the direction adaptation apparatus to be perpendicular to a horizontal plane and installing the first revolute joint on a foundation, the first revolute joint is a turntable bearing, a fixed plate of the turntable bearing is fixed on the foundation, a pallet is fixed on a movable plate thereof, the pallet is fixedly installed on the turntable bearing, and the turntable bearing serves as a part of the base frame.
  5. 5 . The method of claim 3 , wherein, in the step 2 of the method, the universal swing rod apparatus and the direction adaptation apparatus share one revolute joint, the shared revolute joint is a revolute joint for connecting a universal hinge on a universal swing rod to a foundation, the shared revolute joint is formed by a turntable bearing, an axis of the turntable bearing is perpendicular to a horizontal plane, a fixed plate of the turntable bearing is fixed on the foundation, a pallet is fixed on a movable plate thereof, and the turntable bearing serves as a part of the base frame.
  6. 6 . The method for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 3 , wherein the ratio of gravitational moment to be eliminated is within a range from 95% to 105%.
  7. 7 . A device for reducing a positive pressure of an actuating cylinder of a universal hinged support, configured to perform the method for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 1 , wherein the device comprises: a base frame, a force application apparatus, a direction adaptation apparatus, and an integral external connection apparatus; the base frame comprises an external connection unit IA, a main frame, and an external connection unit IB, the force application apparatus comprises a force generation apparatus, a force transmission apparatus, an external connection unit IIA, and an external connection unit IIB, wherein a force generated by the force generation apparatus comprises gravity, a metal spring force, an air spring force, or an electromagnetic force; the direction adaptation apparatus comprises two revolute joints that are not coaxial and not parallel, an external connection unit IIIA, and an external connection unit IIIB, the two revolute joints are fixedly coupled together to achieve rotation with two degrees of freedom; and the integral external connection apparatus comprises an external connection unit VA and an external connection unit VB.
  8. 8 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , further comprising a universal swing rod apparatus, wherein the universal swing rod apparatus comprises a universal hinge, a swing connection rod, an external connection unit IVA and an external connection unit IVB, wherein the universal hinge is connected with one swing connection rod; and the universal swing rod apparatus is installed on a foundation or at a bottom of the base frame, and the universal swing rod apparatus or a cylinder barrel of the actuating cylinder of the universal hinged support is connected with an opposite end of the force application apparatus through the integral external connection apparatus, so as to form a closed loop.
  9. 9 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 8 , wherein a first revolute joint of the direction adaptation apparatus is installed on the ground, an axis of the first revolute joint is perpendicular to the ground, and the first revolute joint is a turntable bearing.
  10. 10 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 8 , wherein the direction adaptation apparatus and a universal swing rod share one revolute joint, this shared revolute joint is a first revolute joint of a connection rod of the universal hinged support, an axis of the revolute joint is perpendicular to the ground, the revolute joint is formed by a turntable bearing, a fixed plate of the turntable bearing is fixed on the foundation, a pallet is fixedly on a movable plate thereof, and the turntable bearing serves as a part of the base frame at the same time, so as to from a base frame with a single rotational degree of freedom.
  11. 11 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the force generation apparatus of the force application apparatus is one tension spring or a set of tension springs, and the force transmission apparatus of the force application apparatus is a universal joint or a combination of universal joints.
  12. 12 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the force transmission apparatus of the force application apparatus is composed of a cable or a cable in cooperation with a pulley or a cable in cooperation with a gearbox, and the force generation apparatus of the force application apparatus is one of the following: one tension spring or a set of tension springs, one torsion spring or a set of torsion springs that generate a pulling force, an air spring equipped with a gearbox, a single pendulum apparatus or a counterweight, an electromagnetic spring, or a torque motor.
  13. 13 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 9 , wherein the force generation apparatus of the force application apparatus is one torsion spring or a set of torsion springs that generate torque, the torsion spring is installed on the turntable bearing, an axis of the torsion spring is horizontal and parallel to a horizontal axis of the universal hinge, and a connection rod of the torsion spring is connected with the actuating cylinder of the universal hinged support through a sliding pair.
  14. 14 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 9 , wherein a fixed plate of the turntable bearing is fixed on the foundation, a pallet is fixedly on a rotatable plate of the turntable bearing, the turntable bearing forms a part of the base frame, and the other parts of the base frame are installed on the pallet, so as to form a base frame with a single rotational degree of freedom.
  15. 15 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the main frame of the base frame has an apparatus capable of adjusting a height or a width of the main frame or an apparatus capable of adjusting both the height and the width of the main frame, and the main frame is fixed after adjustment to form a rigid frame.
  16. 16 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the swing connection rod in the universal swing rod apparatus comprises a mechanism capable of adjusting a distance from the external connection unit IVB to a center of the universal hinge of the universal swing rod apparatus, and the swing connection rod is fixed after adjustment to form a rigid rod.
  17. 17 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 13 , wherein an installation position of the torsion spring is within the following rectangular interval: a coordinate point thereof on an X axis is a point located within a range of 0.05 R 0 to −0.28 R 0 , and a coordinate point thereof on a Y axis is a point located within a range of −0.05 R 0 to 0.28 R 0 .
  18. 18 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the force application apparatus comprises a tensioning adjustment apparatus, and the tensioning adjustment apparatus is connected in series with the force generation apparatus, the force transmission apparatus and the base frame.
  19. 19 . The device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , further comprising a parallel mechanism, wherein the parallel mechanism has at least one UPS branch linkage, a cylinder barrel of a sliding pair of the UPS branch linkage is connected with one end of the force application apparatus, for applying an appropriate anti-gravitational moment to the actuating cylinder so as to form a parallel mechanism system with minimal lateral force.
  20. 20 . A method for reducing a positive pressure of an actuating cylinder of a universal hinged support, using the device for reducing the positive pressure of the actuating cylinder of the universal hinged support of claim 7 , wherein the number of devices for reducing the positive pressure of the actuating cylinder of the universal hinged support that are used ranges from 2 to 6, and a universal swing rod apparatus thereof has a complete UPS branch linkage system; a motion platform and a foundation platform are installed for the UPS branch linkage system according to a configuration of a parallel mechanism; and the UPS branch linkage system, the motion platform, and the foundation platform together form a parallel mechanism, so as to form a parallel mechanism system with minimal positive pressure.

Description

TECHNICAL FIELD The present invention relates to the technical field of hinged support mechanisms, in particular to a method and device for reducing a positive pressure of an actuating cylinder of a universal hinged support. BACKGROUND Many mechanisms nowadays widely use a UPS (including UCS) type branch linkage. In this branch linkage, an active pair (a P pair or a C pair) is a hydraulic cylinder or an electric cylinder (hereinafter referred to as an actuating cylinder). For example, in a parallel mechanism (see FIG. 1.1), the UPS branch linkage swings in a space. The P pair of the UPS branch linkage swings in a two-dimensional space, that is, a working space of the branch linkage is an inclined cone. For such a parallel mechanism system, there are two main problems to be solved. One is the problem of reducing a friction force of the actuating cylinder, and the other is a load problem caused by the weight of the actuating cylinder itself. The problem of friction force requires that a friction force of a sliding pair should be small. At present, a US military aircraft adopts a simulator specification (MIL-S-87241), and a technical specification for a commercial flight simulator is also based on this standard. This specification stipulates that a friction force of an actuating cylinder of a motion system of a flight simulator should be less than a maximum payload of 0.3%. The friction of the actuating cylinder mainly occurs in two parts, one is the friction between a cylinder barrel of the actuating cylinder and a piston, and the other is the friction between a cylinder head and a piston rod. According to a classical tribology theory, the friction is equal to a product of a friction coefficient and a positive pressure (hereinafter referred to as a lateral force). The lateral force refers to a sum of the two positive pressures (also known as the positive pressure), namely, the positive pressure between the cylinder barrel of the actuating cylinder and a diameter of the piston as well as the positive pressure between the cylinder head and a diameter of the piston rod. Reducing one of the two factors such as the friction coefficient and the positive pressure can reduce the friction force. In order to reduce the friction force, most of the methods currently used are to reduce the friction coefficient. There is relatively little research on an effect of the lateral force on the friction force. In practical applications, there are two main solutions for pursuing the low friction coefficient, one is a static pressure support mode, and the other is a combined sealing mode. An extremely low friction coefficient can be obtained by using a hydrostatic bearing. However, a static pressure servo oil cylinder has a complex process, a high manufacturing cost, a limited ability to resist the lateral force (excessive lateral force may cause mechanical wear), a small output length, and a large power load. A friction pair is formed by adopting the combined sealing mode and using a low-friction material. However, such mode cannot withstand the lateral force, causes severe wear, and makes it difficult for the friction force to reach less than 1% of the total load. Therefore, it is far from meeting the smoothness requirements of the flight simulator. Although there are friction compensation, a super-lubricity technology, and so on, the problem still cannot be solved. Data retrieval shows that there is no effective solution for reducing the friction force by reducing the lateral force. In an application environment of a parallel mechanism of the flight simulator, the lateral force is a very important factor affecting the friction force. There are many factors that affect the lateral force, including gravity, an axial force, machining and assembly errors, sealing or guidance, etc. These lateral forces will interact with each other, further increasing the lateral force. Therefore, reducing the lateral force and the mutual influence between the lateral forces can effectively reduce the friction force caused by the lateral force. Analysis shows that among the many factors that affect the lateral force, gravity is the main factor. There is the large lateral force generated by the gravity at the piston of a linear actuating cylinder and a guide sleeve of the cylinder head, and the lateral force is variable. The more the piston rod extends out, the greater the lateral force. When an axis of the actuating cylinder is horizontal and an extension of the piston rod reaches 70%, the lateral force will be greater than the weight of a linear actuator, and will sharply increase with the increase of the extension. For example, a parallel mechanism motion system that drives several tons of weight requires the weight of a single electric cylinder to be hundreds of kilograms or more, which can generate the significant lateral force in the application environment. Especially when the relative output is large and when a tilt angle is small, the lateral