Composite actuator and acting force control method

Abstract

The invention relates to a combined type actuator and an acting force control method, the combined type actuator comprises a hydraulic cylinder, the hydraulic cylinder is internally provided with a piston and a piston rod, and the lower end of the piston rod is fixedly connected with the piston; the piston divides the hydraulic cylinder into an upper cavity and a lower cavity; a first groove is formed in the outer wall of the piston and used for installing a first sealing structure. The upper end of the piston rod penetrates through the hydraulic cylinder and is connected with an external device; an annular cavity is formed between the outer cylinder body assembly and the hydraulic cylinder; the outer cylinder body assembly and the hydraulic cylinder are coaxially fixed, and the lower ends of the outer cylinder body assembly and the hydraulic cylinder are fixed on the base; and the magneto-rheological damping piston assembly is arranged in the annular cavity body. The invention has the advantages of low energy consumption, high stability, good bearing capacity and lateral force resistance, good guidance quality and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electro-hydraulic actuation and smart material applications, and in particular to a composite actuator and force control method. BACKGROUND

[0002] Magnetorheological fluid is a kind of smart material that exhibits significant rheological behavior under the induction of a magnetic field. Under the condition of no external magnetic field, the magnetorheological fluid exhibits good flowability as a Newtonian fluid. When an external magnetic field is applied, the magnetic particles in the magnetorheological fluid are transformed along the direction of the magnetic force line in the carrier liquid, exhibiting a certain yield strength and hindering the flow of the liquid. The controllable damper or shock absorber made of the magnetorheological fluid has been widely used in vibration control and motion control in the fields of vehicles, civil engineering, medical devices, and robots, and has a promising application prospect.

[0003] Magnetorheological shock absorbers have the advantages of fast response, low energy consumption, large adjustable range of damping force, simple structure, and are widely used in semi-active suspensions and vibration isolation systems. However, the magnetorheological shock absorber is a semi-active device that can only regulate the damping force, but cannot actively generate force, and the control function is limited. Although the active devices such as hydraulic actuators, linear motors, and other rotary motors converted by mechanisms can provide active control force, they have high energy consumption and slow response. The existing composite actuators often arrange active devices on the periphery, but this method is difficult to realize integration, and has problems such as poor heat dissipation and poor guiding performance. Moreover, the piston rod of the common magnetorheological shock absorber is a slender rod structure, which will cause insufficient load capacity of the piston rod and insufficient stability under the condition of large lateral force.

[0004] Therefore, a composite actuator and force control method are provided to solve the problems of high energy consumption, poor guiding performance, insufficient load capacity of the piston rod, and insufficient resistance to lateral force of the active devices in the prior art. SUMMARY

[0005] The present application provides a composite actuator and force control method to solve the technical problems in the prior art.

[0006] The technical solutions of the present application to solve the above technical problems are as follows:

[0007] A composite actuator comprises:

[0008] A hydraulic cylinder, the inside of the hydraulic cylinder is provided with a piston and a piston rod, the lower end of the piston rod is fixedly connected with the piston; the piston divides the hydraulic cylinder into an upper cavity and a lower cavity; the outer wall of the piston is provided with a first groove for installing a first sealing structure; the upper end of the piston rod penetrates the hydraulic cylinder and is connected with an external device;

[0009] An outer cylinder assembly is arranged coaxially with the hydraulic cylinder and fixed to the base at the lower end thereof, and forms an annular cavity with the hydraulic cylinder.

[0010] A magneto-rheological damping piston assembly is arranged in the annular cavity.

[0011] In some embodiments, an intermediate cylinder is fixed to one end of the piston and extends through the upper end of the hydraulic cylinder and the upper end of the outer cylinder assembly and is connected to an outer end device.

[0012] In some embodiments, the piston rod is provided with a central hole, and an oil passage is arranged at a position close to the piston, and the oil passage is in communication with the upper cavity and the central hole.

[0013] In some embodiments, the hydraulic cylinder further comprises an inner cylinder, and the upper end of the hydraulic cylinder is provided with a hydraulic cylinder inner guide sealing seat, and a second sealing structure is arranged between the inner hole and the outer wall of the hydraulic cylinder inner guide sealing seat; the lower part of the inner cylinder is provided with a lower cavity oil nozzle, and the oil nozzle of the lower cavity is in communication with the upper end of the piston rod through a hydraulic pipeline and a hydraulic pump system.

[0014] In some embodiments, the upper end of the intermediate cylinder is provided with a fixed end cover, and the fixed end cover is fixedly connected to the upper end of the piston rod; a second groove is arranged in the outer wall of the lower end of the intermediate cylinder, and the second groove is used for mounting a clamping spring.

[0015] In some embodiments, the magneto-rheological damping piston assembly comprises a piston core and a piston sleeve, and an annular gap is formed between the piston core and the piston sleeve; the magneto-rheological damping piston assembly further comprises a piston upper end piece and a piston lower end piece, the piston lower end piece is mounted at the lower end of the piston core, and the piston lower end piece is positioned with the step of the piston core; the piston upper end piece is sleeved on the outside of the intermediate cylinder and tightly fixes the clamping spring.

[0016] In some embodiments, the piston sleeve is sleeved on the outside of the piston core, the piston sleeve is clamped by the piston upper end piece and the piston lower end piece, and the edges of both ends of the piston sleeve are tightly pressed against the piston upper end piece and the piston lower end piece.

[0017] In some embodiments, a third groove is arranged in the outer wall of the piston core, and an electromagnetic coil is wound on the third groove; a wire hole is arranged in the barrel of the intermediate cylinder and the piston core for the wire of the electromagnetic coil to pass through.

[0018] In some embodiments, the outer cylinder assembly comprises an outer cylinder and an outer guide sealing ring, an outer wall of the outer guide sealing ring is provided with a static sealing ring, and an inner wall of the outer guide sealing ring is provided with a guide bushing, a dynamic sealing ring or a dust seal.

[0019] The application also provides a control method of the composite actuator, which is used in the composite actuator as described above, and the method comprises:

[0020] When the actuator works in the semi-active control mode, the current of the electromagnetic coil is completely controlled by the electric control system according to a preset control algorithm to adjust the damping force implemented by the magneto-rheological damper, and at this time, the hydraulic cylinder of the actuator is in a free follow-up state.

[0021] The adjustment mode of the control mode comprises manual adjustment and electric control adjustment.

[0022] The electromagnetic coil is an electromagnetic coil wound on the third groove on the outer wall of the piston core.

[0023] When the actuator works in the active control mode, the electric control system determines the movement direction of the actuator through a sensor, the electric control system calculates the output direction and output size of the actuator according to a preset control algorithm, if the output direction of the actuator is the same as the movement direction of the actuator, the active control force is output by the hydraulic cylinder, and the magneto-rheological damper implements minimum damping force, if the output direction of the actuator is opposite to the movement direction of the actuator, the magneto-rheological damper provides main damping force, and the hydraulic cylinder compensates the difference in force value.

[0024] The adjustment mode of the control mode comprises manual adjustment and electric control adjustment.

[0025] As can be seen from the above, the integration of the magneto-rheological damper and the hydraulic cylinder can expand the function and capacity of the single actuator, and can significantly reduce the energy consumption of the actuator in active control; the slender piston rod of the intermediate cylinder and the hydraulic cylinder is connected with the outside, which can improve the stability of the intermediate cylinder and the piston rod, so that the carrying capacity and the ability to resist lateral force are better; in addition, the use of the three-cylinder structure of the actuator makes the guiding property of the piston better. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The structure diagram of the composite actuator provided by the application;

[0027] Figure 2 The part drawing of the hydraulic cylinder provided by the application;

[0028] Figure 3 The part drawing of the intermediate cylinder and the magneto-rheological damping piston assembly provided by the application;

[0029] Figure 4 Partial sectional view of the gap between the piston core and the piston outer sleeve provided by the present application;

[0030] Figure 5 Parts drawing of the outer cylinder assembly provided by the present application;

[0031] Figure 6 Schematic diagram of the control method of the combined actuator provided by the present application.

[0032] In the drawings, the components represented by each reference numeral are listed as follows:

[0033] 1, upper cavity oil nozzle; 2, fixed end cover; 3, middle cylinder; 4, outer cylinder assembly; 5, magnetorheological damping piston assembly; 6, hydraulic cylinder; 7, base; 8, lower cavity oil nozzle; 9, wire; 10, hydraulic pipeline; 11, hydraulic pump system; 12, piston rod; 13, guide sealing seat in hydraulic cylinder; 14, guide bushing; 15, inner guide sealing ring; 16, inner cylinder; 17, oil passage; 18, piston; 19, communication hole; 20, snap spring; 21, piston core; 22, upper end piece of piston; 23, piston outer sleeve; 24, electromagnetic coil; 25, lower end piece of piston; 26, arc-shaped gap; 27, dustproof seal; 28, static sealing ring; 29, outer guide sealing ring; 30, outer cylinder; 31, dynamic sealing ring. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] In the description of the present application, the terms "first", "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0036] In the description of the present application, the term "for example" is used to indicate "serving as an example, instance, or illustration." Any embodiment described as "for example" in this application is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to practice the application as claimed. In the following description, details are set forth describing specific embodiments. It will be apparent to those skilled in the art, however, that the application can be practiced without using these specific details. In other instances, well-known structures and processes have not been described in detail in order to avoid obscuring the description of the application. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0037] Referring to Figure 1 The composite actuator provided by the present application comprises a hydraulic cylinder 6, the inside of the hydraulic cylinder 6 is provided with a piston 18 and a piston rod 12, the lower end of the piston rod 12 is fixedly connected with the piston 18; the piston 18 divides the hydraulic cylinder 6 into an upper cavity and a lower cavity; the outer wall of the piston 18 is provided with a first groove, the first groove is used for installing a first sealing structure; the upper end of the piston rod 12 penetrates through the hydraulic cylinder 6 and is connected with external devices; an outer cylinder body assembly 4, the outer cylinder body assembly 4 and the hydraulic cylinder 6 form an annular cavity; the outer cylinder body assembly 4 is coaxially fixed with the hydraulic cylinder 6, and the lower ends of the two are fixed on a base 7; a magneto-rheological damping piston assembly 5, the magneto-rheological damping piston assembly 5 is arranged in the annular cavity.

[0038] Specifically, the composite actuator provided by the present application further comprises an intermediate cylinder body 3, one end of the intermediate cylinder body 3 is fixedly connected with the piston 18, the other end penetrates through and extends out of the upper end of the hydraulic cylinder 6, and penetrates through and extends out of the upper end of the outer cylinder body assembly 4 and is connected with external devices;

[0039] In a specific application scenario, the annular cavity formed between the hydraulic cylinder 6 and the outer cylinder body assembly 4 is filled with magneto-rheological fluid, when the piston 18 slides up and down in the annular cavity, the magneto-rheological fluid is forced to flow through the gap of the magneto-rheological damping piston assembly 5; the inner cavity and the outer cavity formed between the intermediate cylinder body 3, the hydraulic cylinder 6 and the outer cylinder body assembly 4 maintain liquid exchange and pressure balance through a plurality of communication holes 19 of the intermediate cylinder body 3 close to the piston; the use of the intermediate cylinder body 3 and the piston rod 12 connected with the outside can improve the stability of the intermediate cylinder body 3 and the piston rod 12, and make the load capacity and the ability to resist lateral force of the actuator better.

[0040] Referring to Figure 2 The piston rod 12 is provided with a central hole, the central hole is provided with an oil passage hole 17 close to the piston 18, and the oil passage hole 17 communicates the upper cavity and the central hole.

[0041] In a specific application scenario, the outer wall of the piston 18 is provided with a groove for mounting a sealing ring, which can prevent hydraulic oil from leaking between the upper cavity and the lower cavity of the inner cylinder body 16.

[0042] Referring to Figure 2 , the hydraulic cylinder 6 further includes an inner cylinder body 16, the upper end of the hydraulic cylinder 6 is provided with a hydraulic cylinder inner guide sealing seat 13, and a second sealing structure is arranged between the inner hole and the outer wall of the hydraulic cylinder inner guide sealing seat 13; the lower part of the inner cylinder body 16 is provided with a lower cavity oil nozzle 8, and the oil nozzle 8 of the lower cavity is in communication with the upper end of the piston rod 12 through a hydraulic pipeline 10 and a hydraulic pump system 11.

[0043] In a specific application scenario, the inside of the hydraulic cylinder 6 is filled with hydraulic oil; the lower part of the inner cylinder body 16 is provided with a lower cavity oil nozzle 8, and the upper end of the piston rod serves as a hydraulic cylinder upper cavity oil nozzle 1; the hydraulic cylinder upper cavity oil nozzle 1 and the hydraulic cylinder lower cavity oil nozzle 8 are in communication through the hydraulic pipeline 10 and the hydraulic pump system 11; when the hydraulic pump system 11 pumps oil to the upper cavity, the hydraulic cylinder outputs force in the contraction direction; when the hydraulic pump system 11 pumps oil to the lower cavity, the hydraulic cylinder outputs force in the extension direction; through the integrated hydraulic cylinder, semi-active control and active control integration can be realized.

[0044] Referring to Figure 3 , the upper end of the intermediate cylinder body 3 is provided with a fixed end cover 2, and the fixed end cover 2 is fixedly connected with the upper end of the piston rod 12; a second groove is formed in the outer wall of the lower end of the intermediate cylinder body 3, and the second groove is used for mounting a snap spring 20.

[0045] Referring to Figure 3 and Figure 4 , the magneto-rheological damping piston assembly 5 includes a piston iron core 21 and a piston outer sleeve 23, and an annular gap is formed between the piston iron core 21 and the piston outer sleeve 23; the magneto-rheological damping piston assembly 5 further includes a piston upper end sheet 22 and a piston lower end sheet 25, and a plurality of small holes or gaps are arranged at the positions of the piston upper end sheet 22 and the piston lower end sheet 25 which are aligned with the annular gap, so that the piston 18 can be penetrated through the annular gap, and the gap is preferably an arc-shaped gap 26 as shown in Figure 4 .

[0046] Specifically, the piston lower end piece 25 is installed at the lower end of the piston core 21, and the piston lower end piece 25 is positioned with the piston core 21 by steps to ensure the coaxiality of the two; the cylinder body of the intermediate cylinder 3 and the piston core 21 are both provided with a wire hole for the lead wire 9 of the electromagnetic coil 24 to pass through, the piston upper end piece 22 is sleeved outside the intermediate cylinder 3 and tightly fixes the clamping spring 20, and the third groove is provided on the outer wall of the piston core 21, and the electromagnetic coil 24 is wound on the third groove. The piston sleeve 23 is sleeved outside the piston core 21, the piston sleeve 23 is clamped by the piston upper end piece 22 and the piston lower end piece 25, and the two ends of the piston sleeve 23 are curled to tightly press the piston upper end piece 22 and the piston lower end piece 25, so that the intermediate cylinder 3, the piston core 21, the piston upper end piece 22, the piston lower end piece 25 and the piston sleeve 23 are permanently integrated.

[0047] In a specific application scenario, when the electromagnetic coil 24 is not powered, the magnetorheological fluid in the gap of the magnetorheological damper piston assembly 5 presents a liquid state with good fluidity, and the damping force of the piston 18 sliding is small; when the electromagnetic coil 24 is powered, a magnetic field is generated in the gap, the magnetorheological fluid in the gap is induced to present a solid-like state with poor fluidity, and the damping force of the piston 18 sliding is increased; and the greater the current load, the stronger the magnetic field in the gap, the poorer the fluidity of the magnetorheological fluid, and the greater the damping force of the piston 18 sliding. After the current is cut off, the magnetic field disappears, and the magnetorheological fluid in the gap returns to a liquid state with good fluidity, and the shock absorber presents a small damping force. Therefore, by controlling the current of the electromagnetic coil 24, the damping force of the shock absorber can be adjusted, so that the kinematics or dynamics control of the external device connected to the intermediate cylinder 3 can be realized.

[0048] Referring to Figure 5 , the outer cylinder assembly 4 includes an outer cylinder 30 and an outer guide sealing ring 29, the outer wall of the outer guide sealing ring 29 is provided with a static sealing ring 28, and the inner wall of the outer guide sealing ring 29 is provided with a guide bushing 14, a dynamic sealing ring 31 or a dust seal 27.

[0049] On the basis of the above-mentioned composite actuator, the application further provides a control method of the composite actuator, as shown in Figure 6 , for the composite actuator as described above, the method comprises the following steps:

[0050] When the actuator works in the semi-active control mode, the current size of the electromagnetic coil is completely controlled by the electric control system according to the preset control algorithm to adjust the damping force implemented by the magnetorheological shock absorber, and at this time, the hydraulic cylinder of the actuator is in a free follow-up state;

[0051] The adjustment mode of the control mode includes manual adjustment and electric control adjustment.

[0052] The electromagnetic coil is an electromagnetic coil wound on the third groove of the outer wall of the piston core.

[0053] When the actuator works in the active control mode, the electric control system determines the movement direction of the actuator through the sensor, and calculates the output direction and the output size of the actuator according to the preset control algorithm; if the output direction of the actuator is the same as the movement direction of the actuator (such as the first and third quadrants shown in the figure), the active control force is output by the hydraulic cylinder, and the magneto-rheological damper implements the minimum damping force; if the output direction of the actuator is opposite to the movement direction of the actuator (such as the second and fourth quadrants shown in the figure), the magneto-rheological damper provides the main damping force, and the hydraulic cylinder compensates the balance force value. Figure 6 Figure 6

[0054] The adjustment mode of the control mode includes manual adjustment and electric control adjustment.

[0055] In a specific application scenario, if the output direction of the actuator is opposite to the movement direction of the actuator, the method of bearing the main damping force by the magneto-rheological damper and compensating the balance force value by the hydraulic cylinder can make the magneto-rheological damper provide larger damping force with extremely low energy consumption, thereby reducing the overall energy consumption of the actuator.

[0056] Although the preferred embodiments of the present application have been described, those skilled in the art who have the basic inventive concept can make further changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0057] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.​​

Claims

1. A compound actuator characterized by, The hydraulic cylinder is internally provided with a piston and a piston rod, the lower end of the piston rod is fixedly connected with the piston, the piston divides the hydraulic cylinder into an upper cavity and a lower cavity, the outer wall of the piston is provided with a first groove for installing a first sealing structure, the upper end of the piston rod penetrates the hydraulic cylinder and is connected with external devices; An outer cylinder assembly is formed with an annular cavity with the hydraulic cylinder, the outer cylinder assembly is coaxially fixed with the hydraulic cylinder, and the lower ends of the two are fixed on a base; A magneto-rheological damping piston assembly is arranged in the annular cavity. Further comprising:

2. The hybrid actuator of claim 1, wherein An intermediate cylinder is fixedly connected with the piston at one end, penetrates and extends out of the upper end of the hydraulic cylinder at the other end, and penetrates and extends out of the upper end of the outer cylinder assembly and is connected with external devices. The piston rod is provided with a central hole, the central hole is provided with an oil passage near the piston, and the oil passage communicates the upper cavity and the central hole.

3. The hybrid actuator of claim 1, wherein The hydraulic cylinder further comprises an inner cylinder, the upper end of the hydraulic cylinder is provided with a hydraulic cylinder inner guiding sealing seat, a second sealing structure is arranged between the inner hole and the outer wall of the hydraulic cylinder inner guiding sealing seat, the lower part of the inner cylinder is provided with a lower cavity oil nozzle, and the oil nozzle of the lower cavity is communicated with the upper end of the piston rod through a hydraulic pipeline and a hydraulic pump system.

4. The hybrid actuator of claim 1, wherein The upper end of the intermediate cylinder is provided with a fixed end cover, the fixed end cover is fixedly connected with the upper end of the piston rod, and the lower end of the intermediate cylinder is provided with a second groove in the outer wall, the second groove is used for installing a clamping spring.

5. The hybrid actuator of claim 2, wherein, The magneto-rheological damping piston assembly comprises a piston core and a piston sleeve, an annular gap is formed between the piston core and the piston sleeve, the magneto-rheological damping piston assembly further comprises an upper piston end plate and a lower piston end plate, the lower piston end plate is installed at the lower end of the piston core, and the lower piston end plate is positioned with the step of the piston core, the piston upper end plate is sleeved outside the intermediate cylinder, and the clamping spring is pressed and fixed.

6. The hybrid actuator of claim 5, wherein, The piston sleeve is sleeved outside the piston core, the piston sleeve is clamped by the piston upper end plate and the piston lower end plate, and the both ends of the piston sleeve are curled and pressed to tightly fix the piston upper end plate and the piston lower end plate.

7. The hybrid actuator of claim 6, wherein The outer wall of the piston core is provided with a third groove, an electromagnetic coil is wound on the third groove, and a wire hole is formed in the barrel of the intermediate cylinder and the piston core for the wire of the electromagnetic coil to pass through.

8. The hybrid actuator of claim 7, wherein, The outer cylinder assembly comprises an outer cylinder and an outer guiding sealing ring, the outer wall of the outer guiding sealing ring is provided with a static sealing ring, and the inner wall of the outer guiding sealing ring is provided with a guiding bushing, a dynamic sealing ring or a dust seal.

9. The hybrid actuator of claim 1, wherein, The control method comprises the following steps:

10. A control method based on the compound actuator according to any one of claims 1 to 9, characterized by, When the actuator works in a semi-active control mode, the current of the electromagnetic coil is completely controlled by an electric control system according to a preset control algorithm to adjust the damping force of the magneto-rheological damper, and at this time, the hydraulic cylinder of the actuator is in a free follow-up state; The adjustment mode of the control mode comprises manual adjustment and electric control adjustment; The electromagnetic coil is an electromagnetic coil wound on the third groove of the outer wall of the piston core. ​ When the actuator works in the active control mode: the electric control system determines the movement direction of the actuator through a sensor, and calculates the output direction and size of the actuator according to a preset control algorithm; if the output direction of the actuator is the same as the movement direction of the actuator, the active control force is output by the hydraulic cylinder, and the magneto-rheological damper implements minimum damping force; if the output direction of the actuator is opposite to the movement direction of the actuator, the magneto-rheological damper provides main damping force, and the hydraulic cylinder compensates the balance force value; The adjustment mode of the control mode comprises manual adjustment and electric control adjustment.

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