KR20120019548A - Actuator using magneto rheological unit and driving method thereof - Google Patents

Abstract

PURPOSE: An actuator using a magneto rheological unit and a driving method thereof are provided to control the working distance and speed of a driving unit by composing the driving unit with a smooth impact drive mechanism. CONSTITUTION: A piezo actuator(110) is expanded according to an applied voltage. A magneto rheological unit(120) is included on one side of the piezo actuator. The magneto rheological unit is movable according to the expansion and contraction of the piezo actuator. A magnetic fluid(121) is included in the magneto rheological unit. A driving unit(130) is combined with an end part of the magneto rheological unit.

Description

Actuator using Magneto Rheological Unit and Driving Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driver using a magnetorheological unit, and more particularly, to a driver having a small volume and excellent response characteristics by using a property of a magnetorheological body whose stiffness changes with the strength of a magnetic field, and a driving method thereof.

In general, magnetorheological (MR) refers to a non-colloidal solution in which particles having a micron size magnetism are dispersed in a non-conductive solvent such as silicone oil or mineral oil. In the case where the magnetic field is not loaded, the dispersed particles have Newtonian fluid properties, but when the magnetic field is loaded, the dispersed particles are polarized to form fibers in a direction parallel to the loaded magnetic field, and thus have resistance to shear or flow. Therefore, the intensity is changed according to the change of the magnetic field, it is used in various industrial fields.

Conventional electromagnetic motors are provided with a power transmission unit such as a gear between a motor and a plurality of drive shafts to implement multiple degrees of freedom as a single motor, and the motor and necessary drive shafts are connected by converting positions of such gears. This power transmission method has to have a separate drive device for converting the position of the power transmission unit such as a gear connecting the motor and the drive shaft, there is a disadvantage that the volume of the equipment is increased and the weight is increased. In addition, since the motor and the drive shaft are connected directly through a power transmission unit such as a gear, there is a problem that the power transmission efficiency is lowered.

In order to solve this problem, a driver using a shape memory alloy or a shape memory polymer has been disclosed. They have the advantage of obtaining a large number of degrees of freedom even in a narrow space, but the response characteristics are poor, there is a problem that the response speed is slow. In addition, drivers using the conventional Smooth Impact Drive Mechanism (SIDM) have to use one piezo to obtain one degree of freedom, which leads to complicated and bulky equipment to obtain multiple degrees of freedom. There is.

Therefore, there is a demand for the development of a driver and its driving method using a magnetorheological unit capable of controlling a plurality of driving devices by implementing multiple degrees of freedom from a single energy source while showing a simple and fast response structure for installation in a narrow space. do.

The present invention has been made in view of the above-described problems, the structure is simple and can be installed even when there is a space limitation by reducing the volume of the equipment, by applying a magnetorheological unit fast response characteristics and multiple degrees of freedom implementation It is an object of the present invention to provide a driver using a magnetorheological unit capable of controlling two driving devices and a driving method thereof.

The driver using the magnetorheological unit according to an embodiment of the present invention, the piezo actuator 110 is stretched in accordance with the applied voltage; The magnetorheological unit 120 is provided on one side of the piezo actuator 110 and flows according to the expansion and contraction of the piezo actuator 110, and includes a magnetorheological body 121 whose rigidity changes depending on the strength of the detected magnetic field. ); A driving unit 130 coupled to an end of the magnetorheological unit 120 for driving; Including, the magnetorheological unit 120 is characterized in that for transmitting the driving force by the expansion and contraction of the piezo actuator 110 to the drive unit 130 in response to the stiffness change of the magnetorheological body 121. do.

In addition, the actuator using the magnetorheological unit according to an embodiment of the present invention, the magnetorheological body 121 included in the magnetorheological unit 120 is at least any one of a magnetorheological fluid, a magnetorheological elastomer, a magnetorheological gel. It is characterized by one or more.

In addition, the driver using a magnetorheological unit according to an embodiment of the present invention, the magnetorheological unit 120 is provided with a plurality on one side of the piezo actuator 110, characterized in that arranged at a predetermined interval spaced. It is done.

On the other hand, the driver using the magnetorheological unit according to an embodiment of the present invention, the drive unit 130 is a slider coupled to the end of the magnetorheological unit 120 and the rod coupled to the slider 131 132 is provided, the shock mitigation that the drive distance of the slider 131 is variable according to the difference between the friction force and the inertia force between the slider 131 and the rod 132 flowing along the magnetic rheological unit 120 It is characterized by a drive mechanism.

A driving method of a driver using a magnetorheological unit according to an embodiment of the present invention includes: (a) a first input step of gradually increasing a voltage and applying a voltage to the piezo actuator 110; (b) an expansion step of gradually expanding the piezo actuator 110 according to the voltage applied in step (a); (c) the kinetic energy generated as the piezo actuator 110 is gradually expanded in step (b) is transferred to the driving unit 130 through the magnetorheological unit 120 to the slider 131 and the A first driving step in which the rod 132 is driven together; (d) a second input step of rapidly lowering the voltage and applying a voltage to the piezo actuator 110; (e) a contraction step in which the piezo actuator 110 contracts rapidly according to the voltage applied in step (d); (f) In the step (e), the kinetic energy generated as the piezo actuator 110 contracts rapidly is transferred to the driving unit 130 through the magnetorheological unit 120 so that the slider 131 is not driven. A second driving step in which only the rod 132 is driven without being driven; It consists of, characterized in that to perform the (a) to (f) step repeatedly.

In addition, the driving method of the driver using a magnetorheological unit according to an embodiment of the present invention, after performing the step (f), is supplied to the magnetorheological body 121 included in the magnetorheological unit 120. A driving control step of controlling the driving amount of the driving unit 130 by controlling the strength of the magnetic field; It is further included, characterized in that to perform the steps (a) to (f) repeatedly.

A driver using a magnetorheological unit and a driving method thereof according to an embodiment of the present invention,

First, since the magnetorheological unit whose stiffness is changed according to the strength of the magnetic field is passed, when a plurality of driving units are provided, the control of the operation speed and the operation speed of each driving unit is easily controlled by adjusting the strength of the magnetic field in each magnetoresistive unit. There is an advantage to this.

Second, the magnetorheological body included in the magnetorheological unit may be provided as a magnetorheological fluid (MR fluid, MRF), a magnetorheological elastomer (MR elastomer, MRE), a magnetorheological gel (MR gel, MRG), the driving device Various materials can be used in consideration of the required torque and travel distance.

Third, since a plurality of magnetorheological units are provided and arranged at predetermined intervals, there is an advantage of implementing multiple degrees of freedom from one power source and separately controlling each driving unit.

Fourth, when the driving unit is provided with a shock mitigation drive mechanism (hereinafter referred to as 'SIDM'), it is possible to adjust the operating distance and the speed of each driving unit according to the magnitude and speed of the voltage applied to the piezo actuator.

Fifth, as the voltage applied to the piezo actuator gradually rises and falls rapidly, the piezo actuator gradually expands and contracts rapidly, and accordingly, SIDM flows in one direction according to the difference between the frictional and inertial forces of the rod and slider. There are advantages to it.

Sixth, after observing the driving stage of the driver, the magnetic field strength of the magnetorheological body coupled to each driving unit is adjusted according to the driving amount required in each driving unit. have.

1 is a perspective view showing a schematic structure of a driver using a magnetorheological unit according to an embodiment of the present invention.
2 is a graph showing an input value of a voltage applied to a piezo actuator according to an embodiment of the present invention.
3 is a structural diagram showing that the piezo actuator is stretched in response to the voltage input shown in FIG.
4 is a structural diagram showing an operating state when a driving unit is provided as a shock mitigating drive mechanism in a driver using a magnetorheological unit according to an embodiment of the present invention.

In general, rheology includes electric rheology and magnetic rheology, and the former means that the property changes according to the input of the magnetic field. Magnetic rheology (MR) is a phenomenon in which a state changes depending on the strength of a magnetic field when the magnetic field is applied to a solvent such as a fluid, an elastomer, a gel, or a sol, thereby curing. Therefore, it is used in various industries including the automobile and aviation sectors. For example, when used in an automobile, a magnetorheological body may be used in a shock absorber that may adjust attenuation characteristics according to a driving condition of a vehicle and a driver's selection.

Hereinafter, a driver using a magnetorheological unit according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a perspective view showing a schematic structure of a driver using a magnetorheological unit according to an embodiment of the present invention, Figure 2 is a graph showing the input value of the voltage applied to the piezo actuator according to an embodiment of the present invention 3 is a structural diagram showing that the piezo actuator is stretched according to the voltage input shown in FIG. 2, and FIG. 4 is a case where the driving unit is provided as a shock mitigating drive mechanism in a driver using a magnetorheological unit according to an embodiment of the present invention. The structural diagram which shows the operation state of is shown.

Referring to FIG. 1, a driver 100 using a magnetorheological unit includes a piezo actuator 110, a magnetorheological unit 120, and a driver 130, and the driver 130 includes a slider 131 and a rod 132. It may be provided as). Piezos provided in the piezo actuator 110 are known materials that deform in response to voltage or charge. Piezos may have a shape that changes in length or shears in response to an applied control signal, and may be deformed in both a length and a shear direction. The change in length or shear distance of the piezo changes linearly with respect to the amount of charge supplied by the applied voltage under conditions without external load. The driving method using the piezoelectric element has relatively little noise and vibration compared to the motor driving method, and has an advantage of greatly reducing power consumption. The piezo actuator 110 is expanded or contracted in the length and shear direction according to the applied voltage. 3 illustrates a state in which the piezo actuator 110 is expanded or contracted according to an applied voltage. The expansion and contraction by the expansion or contraction of the piezo actuator 110 is a power source of the driver 100 using the magnetorheological unit. Therefore, the piezo actuator 110 is preferably connected to the electrical equipment to apply a voltage.

Referring to FIG. 1, the magnetorheological unit 120 is formed on one side of the piezo actuator 110, and a magnetorheological body 121 and an electromagnetic body 122 may be provided. When the piezo actuator 110 expands or contracts in the longitudinal direction and the shear direction according to the applied voltage, the magnetorheological unit 120 flows in conjunction with it. However, the magnetorheological unit 120 includes the magnetorheological body 121 whose rigidity changes according to the strength of the magnetic field. Accordingly, since the magnetic rheological unit 120 has a small rigidity in a state such as fluid or elastomer when no magnetic field is applied, the magnetic rheological unit 120 has a driving force transmitted from one side of the magnetic rheological unit 120 to the other side. Absorption is not delivered to the part or only part of it is delivered. On the contrary, when the magnetic field unit 120 is applied with a magnetic field, the stiffness increases according to its strength, and thus, the driving force transmitted from one side of the magnetic field unit 120 is easily transmitted to the other side.

The reaction rate at which the magnetorheological unit 120 changes stiffly according to a magnetic field is typically several ms (milliseconds), and thus has excellent response characteristics, which is advantageous for power transmission. Therefore, the magnetorheological unit 120 is a power transmission unit for transmitting a driving force that expands or contracts according to the voltage applied to the piezo actuator 110 to the drive unit 130. However, as described above, the stiffness varies depending on the magnetic field, and the stiffness varies according to the strength of the magnetic field applied to the magnetorheological body 121, and the driving force is variably transmitted in response thereto.

The magnetorheological body 121 included in the magnetorheological unit 120 may be selected from a magnetorheological fluid (MR fluid, MRF), a magnetorheological elastomer (MR elastomer, MRE), and a magnetorheological gel (MR gel, MRG). And combinations of these and other materials. In addition, the magnetorheological unit 120 is provided on one side of the piezo actuator 110 in plurality, preferably spaced apart at predetermined intervals. When the piezo actuator 110 is a power source and the magnetorheological unit 120 is a power transmission unit for transmitting power to the drive unit 130, a plurality of magnetorheological units 120 in one piezo actuator 110. ) Is provided with the advantage of driving multiple devices from one power source. In addition, since the respective driving devices can be driven differently by supplying different magnetic fields for each of the magnetic rheological units 120 which are power transmission units, there is an advantage of high degree of freedom for controlling the driving devices.

The driving unit 130 is coupled to the end of the magnetorheological unit 120 to be driven. Therefore, in order to transfer the power generated from the piezo actuator 110 to any one drive unit 130, the user may use the electromagnetic body 122 included in the magnetorheological unit 120 coupled to the drive unit 130. The magnetic field can be applied through When greater power is required in the drive unit 130, a larger magnetic field may be supplied to the magnetorheological body 121 through the electromagnetic body 122 to increase power transmission efficiency. On the contrary, when the driving unit 130 is not driven or requires small power, the electromagnetic unit 122 may be adjusted to block or reduce the size of the magnetic field supplied to the magnetorheological body 121.

1 and 4, the driving unit 130 may be provided with a slider 131 coupled to an end of the magnetorheological unit 120 and a rod 132 coupled to the slider 131. The slider 131 flows while generating a constant friction with the rod 132. When the pressure is slowly supplied to the slider 131, the friction force between the slider 131 and the rod 132 is greater than the inertia force of the slider 131, so that the slider 131 and the rod 132 are It will flow in one piece. On the contrary, when the pressure is rapidly supplied to the slider 131, the frictional force between the slider 131 and the rod 132 is smaller than the inertia force of the slider 131, so that the slider 131 and the rod 132 are inclined. The slider 131 is inserted into or withdrawn from the rod 132 without the unitary flow, and the rod 132 does not flow or flows relatively small. In FIG. 4, the difference in friction and inertia between the slider 131 and the rod 132 is generated according to the flow velocity, and the shock mitigation drive mechanism having the variable driving distance of the slider 131 varies according to the difference. SIDM) is shown. In addition, 'x' refers to the unit moving distance caused by the difference between the friction force and the inertia force between the slider 131 and the rod 132.

Hereinafter, the driving method using the driver 100 using the magnetorheological unit will be described sequentially.

(a) first input step

In FIG. 2, the input value of the voltage input to the said piezo actuator 110 is shown. As shown in FIG. 2, a voltage is applied to the piezo actuator 110 while gradually increasing the input voltage.

(b) expansion stage

The piezo actuator 110 is expanded according to the voltage applied in the step (a), but since the applied voltage is gradually increased, the expansion speed of the piezo actuator 110 is also gradually expanded and gradually generates a driving force. do.

(c) first driving step

In the step (c), the driving force generated as the piezo actuator 110 is gradually expanded, that is, the kinetic energy is transmitted to the driving unit 130 via the magnetorheological unit 120 which is a power transmission unit. At this time, as described above, it is possible to control the power transmission efficiency or cut off the power by adjusting the stiffness according to the strength of the magnetic field applied to the magnetic rheological unit 120. When the driving unit 130 is a shock mitigating drive mechanism (SIDM), the slider 131 and the rod 132 are integrally flowed because the piezo actuator 110 gradually expands.

(d) second input stage

As shown in FIG. 2, a voltage is applied to the piezo actuator 110 while rapidly decreasing the input voltage.

(e) contraction phase

In the step (d), the piezo actuator 110 rapidly contracts according to the applied voltage and rapidly generates a driving force by the rapid contraction.

(f) second drive step

In step (e), the driving force, that is, the kinetic energy generated as the piezo actuator 110 is rapidly contracted, is transmitted to the driving unit 130 via the magnetorheological unit 120 which is a power transmission unit. As described above, power transmission may be adjusted in the magnetorheological unit 120. When the driving unit 130 is a shock mitigating drive mechanism (SIDM), since the piezo actuator 110 contracts rapidly, the slider 131 and the rod 132 do not flow integrally, and the rod 132 does not flow. Only flow will return to its original position.

Steps (a) to (f) may be performed one cycle and may be repeatedly performed. In addition, as described above, after performing step (f), the driving amount of the driving unit 130 is controlled by controlling the intensity of the magnetic field supplied to the magnetorheological body 121 included in the magnetorheological unit 120. (Drive control step) When the driving amount of the drive unit 130 is adjusted, the operation is repeatedly performed from step (a) again to drive the device.

The driver 100 using the magnetorheological unit may be utilized in various industrial fields, and will be described below with an example. First, the new interface device of the electronic device, can be utilized in the robot industry. In particular, in the case of electronic devices, communication devices such as mobile phones can be utilized as haptic devices, real 3D digital display frames, and braille displays. In the military industry, it can be used to check the combat environment and to provide military maps for military deployment simulation. In the robot industry, it can be used to simulate the multiple degree of freedom driver for the movement of the robot manipulator, the facial movement and the skin movement of the robot. Since the above-described use example is only one example, it can be used in an industrial field not mentioned.

The technical idea should not be interpreted as being limited to the above-described embodiment of the present invention. Various modifications may be made at the level of those skilled in the art without departing from the spirit of the invention as claimed in the claims. Therefore, such improvements and modifications fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

100: driver using magnetorheological unit
110: piezo actuator 120: magnetorheological unit
121: magnetorheological body 122: electromagnetic body
130: drive unit 131: slider
132: load

Claims (6)

A piezo actuator 110 which is stretched according to an applied voltage;
The magnetorheological unit 120 is provided on one side of the piezo actuator 110 and flows according to the expansion and contraction of the piezo actuator 110, and includes a magnetorheological body 121 whose rigidity changes depending on the strength of the detected magnetic field. );
A driving unit 130 coupled to an end of the magnetorheological unit 120 for driving;
Including,
The magnetorheological unit 120 is a magnetorheological unit that transmits the driving force by the expansion and contraction of the piezo actuator 110 to the drive unit 130 in response to a change in the rigidity of the magnetorheological body 121. Driver using.
The method of claim 1,
The magnetorheological body (121) included in the magnetorheological unit (120) is a driver using a magnetorheological unit, characterized in that at least one or more of a magnetorheological fluid, a magnetorheological elastomer, a magnetorheological gel.
The method of claim 2,
The magnetorheological unit (120) is provided with a plurality on one side of the piezo actuator 110, the driver using a magnetorheological unit, characterized in that arranged at a predetermined interval spaced.
The method according to any one of claims 1 to 3,
The drive unit 130 is provided with a slider 131 coupled to the end of the magnetorheological unit 120 and a rod 132 coupled to the slider 131,
It is characterized in that the impact relief drive mechanism is characterized in that the drive distance of the slider 131 is variable according to the difference between the friction force and inertial force between the slider 131 and the rod 132 flowing along the magnetorheological unit 120 Driver using magnetorheological unit.
The driving method of the driver using the magnetorheological unit of claim 4,
(a) a first input step of gradually increasing the voltage and applying a voltage to the piezo actuator (110);
(b) an expansion step of gradually expanding the piezo actuator 110 according to the voltage applied in step (a);
(c) the kinetic energy generated as the piezo actuator 110 is gradually expanded in step (b) is transferred to the driving unit 130 through the magnetorheological unit 120 to the slider 131 and the A first driving step in which the rod 132 is driven together;
(d) a second input step of rapidly lowering the voltage and applying a voltage to the piezo actuator 110;
(e) a contraction step in which the piezo actuator 110 contracts rapidly according to the voltage applied in step (d);
(f) In the step (e), the kinetic energy generated as the piezo actuator 110 contracts rapidly is transferred to the driving unit 130 through the magnetorheological unit 120 so that the slider 131 is not driven. A second driving step in which only the rod 132 is driven without being driven;
The method of claim 1, wherein the steps of (a) to (f) are repeatedly performed.
The method of claim 5, wherein
After performing the step (f), the drive control step of controlling the driving amount of the drive unit 130 by controlling the intensity of the magnetic field supplied to the magnetorheological body 121 included in the magnetorheological unit 120 ;
Further comprising a, the method of driving a driver using a magnetorheological unit, characterized in that to perform the steps (a) to (f) repeatedly.

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