JP4376052B2 - Giant magnetostrictive actuator - Google Patents

Description

  The present invention relates to a giant magnetostrictive actuator using a giant magnetostrictive material.

The giant magnetostrictive material has a very large magnetostriction of about 100 times that of a normal magnetostrictive material, and has various advantages over, for example, a typical piezoelectric material of a solid displacement element. Yes. That is, the giant magnetostrictive material can convert electrical energy into mechanical energy with very high efficiency, generates a large force, has a very large expansion / contraction rate, excellent responsiveness, extremely high durability, and simple structure. . For this reason, in recent years, interest in the practical application of magnetostrictive actuators using this super magnetostrictive material has increased, and several research publications have been made (for example, Non-Patent Documents 1 and 2).
“Hysteresis Compensation Method for Giant Magnetostrictive Actuators” Ryo Kondo, Hiroki Arita et al. Proceedings of the 7th IEEJ Ibaraki Branch Conference (1998) “Study on High Functional Devices-Research on Giant Magnetostrictive Actuator-” Kenji Asano 1999 Ibaraki Industrial Technology Center Research Report (1998)

In Non-Patent Document 1, since the giant magnetostrictive material has hysteresis characteristics, it is necessary to compensate for fine positioning and the like, and the plant is regarded as a product of a function H representing hysteresis and a linear plant P _0. A method of canceling the hysteresis is disclosed by multiplying this by the inverse function H ⁻¹ of the hysteresis.

  Non-Patent Document 2 discloses a method of applying control that cancels hysteresis characteristics to a giant magnetostrictive actuator.

  According to the above-mentioned non-patent documents, all are based on the Preisach model, and once the hysteresis characteristic of the giant magnetostrictive material is measured, a complicated work is required, and if the giant magnetostrictive material is different, the above work is performed each time. There is a problem that it takes. In the case of the above method, the power source is basically limited to direct current. Further, in the case of the above method, the control needs to be performed by software, and there is a problem that it becomes complicated.

  An object of the present invention is to eliminate such a conventional problem. An object of the present invention is to provide a giant magnetostrictive actuator having a simple configuration that can easily compensate for hysteresis.

  In order to solve the above problems, the first invention of the present application has a rod member made of a giant magnetostrictive material and a flange portion made of a magnetic material, and is fixedly supported in a state of being in contact with one end of the rod member. A member and a flange portion made of a magnetic material are disposed in contact with the other end portion of the rod member, and are integrally displaced with the other end portion on the side opposite to the other end side. A movable support member with an output end projecting, and a cylindrical driving coil located between the flange portions and surrounding the outside of the rod member, and located between the flange portions, A permanent magnet arranged at a position close to the rod member capable of applying a bias magnetic field for extending the rod member to the rod member and a position inside the driving coil pass through this position. Proportional to the time change rate of magnetic flux Magnetic flux detecting means for outputting an electric signal whose voltage changes, an opening at one end, and housing the rod member, fixed support member, movable support member, driving coil, permanent magnet, and magnetic flux detection means, A hollow casing having the output end positioned in the opening, an integrator, an adder, and a driver. The integrator integrates a voltage changing electric signal from the magnetic flux detection means. The electrical signal proportional to the magnetic flux is output, and the adder receives an electrical signal corresponding to the target displacement amount of the output end from the outside, and the integrator from the voltage component of the electrical signal The driver outputs an electric signal having a voltage component obtained by subtracting the voltage component of the electric signal from the driver, and the driver introduces a current that fluctuates in response to the voltage fluctuation of the electric signal from the adder from the power source to the driving coil. And a configuration in which a control unit that is formed so as to act.

  In the second invention, in addition to the structure of the first invention, the magnetic flux detecting means is a magnetic flux detecting coil disposed around the rod member.

  In the third aspect of the invention, in addition to the structure of the first aspect of the invention, the magnetic flux detecting means is a Hall element disposed in the middle portion of the rod member.

  In the fourth aspect of the invention, in addition to the structure of any one of the first to third aspects, an elastic member that constantly urges the flange portion of the movable support member in a direction toward the driving coil is provided.

  In the fifth aspect of the invention, in addition to any one of the first to fourth aspects of the invention, the permanent magnet is provided on the outer periphery of the driving coil.

  In the sixth aspect of the invention, in addition to any one of the first to fourth aspects of the invention, the permanent magnet is provided at both ends of the driving coil.

  According to the giant magnetostrictive actuator according to the present invention, hysteresis compensation can be easily performed, and there is an effect that it can be formed compactly with a simple configuration.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a giant magnetostrictive actuator 1 according to a first embodiment of the present invention. The giant magnetostrictive actuator 1 is an alloy composed of, for example, terbium, dysprosium, iron, etc., and a giant magnetostrictive material that is a ferromagnetic material. This utilizes the magnetostriction characteristic of the rod member 11 made of In the giant magnetostrictive actuator 1, the rod member 11 includes a fixed support member 12, a movable support member 13, a drive coil 14, a permanent magnet 15, a magnetic flux detection coil 16 as an example of magnetic flux detection means, and an example of an elastic member. It is accommodated in the casing 18 together with the disc spring 17 and the rod member 11 is formed such that the rod member 11 is feedback-controlled by the control unit 19 as described below.

The fixed support member 12 has a flange portion 21 made of a magnetic material capable of forming a closed magnetic circuit, and a central protruding portion is in contact with one end portion of the rod member 11.
The movable support member 13 has a flange portion 22 made of a magnetic member capable of forming a closed magnetic circuit, has a protruding portion in contact with the other end portion of the rod member 11 at the center, and is opposite to the other end portion. And an output end portion 23 projecting from the bottom.
The driving coil 14 is located between the flange portions 21 and 22 and is formed in a cylindrical shape surrounding the outside of the rod member 11.
The permanent magnet 15 is formed in a cylindrical shape, is located between the flange portions 21 and 22 like the driving coil 14, is provided outside the driving coil 14, and extends the rod member 11. A bias magnetic field is applied in advance, and a bias displacement is applied in advance to the output end 23 of the movable support member 13 that contacts the rod member 11.
The magnetic flux detection coil 16 is provided inside the drive coil 14 so as to surround the rod member 11, and outputs an electric signal whose voltage changes in proportion to the time change rate of the magnetic flux passing therethrough.
The disc spring 17 is interposed between the flange portion 22 of the movable support member 13 and the end portion of the casing 17 on the movable support member 13 side, and constantly biases the flange portion 22 in the direction toward the drive coil 14. Yes. As a result, the other end portion of the rod member 11 and the projecting portion of the movable support member 13 are always kept in contact with each other, and the output end portion 23 is displaced integrally with the other end portion.
As described above, the casing 18 accommodates the rod member 11 and the like, and has an opening 24 for positioning the output end 23.

The control unit 19 includes an integrator 31, an adder 32, and a driver 33. As will be described below, the control unit 19 controls the current led from the power source 41 to the driving coil 14 based on the electrical signal from the magnetic flux detection coil 16. The amount of displacement of the output end 23 is controlled via
The integrator 31 receives from the magnetostriction detection coil 16 an electric signal generated by the electromotive force generated as a result of the magnetic flux change, that is, an electric signal whose voltage changes in proportion to the time change rate of the magnetic flux. Integrates and outputs an electrical signal proportional to the magnetic flux.
The adder 32 receives in advance an electric signal corresponding to the target displacement amount of the output end 23 from the outside, and receives an electric signal obtained as a result of the integration from the integrator 31, and inputs the electric signal from the outside from the electric signal. The electric signal obtained by subtracting the electric signal is output.
The driver 33 is interposed between the power source 41 and the driving coil 14 and controls the current guided to the driving coil 14 based on the electric signal obtained by the above reduction from the adder 32.

  FIG. 2 shows a state in which the generated displacement at the output end 23 changes with respect to the input current to the driving coil 14 of the giant magnetostrictive actuator 1. 3 shows the output terminal when the magnetic flux detecting coil 16, the integrator 31, and the adder 32 are removed from the giant magnetostrictive actuator 1, and a current is guided to the driving coil 14 through the driver 33 in the same manner as in FIG. The state in which the generated displacement in the part 23 changes is shown. As can be seen from these figures, in the giant magnetostrictive actuator 1, as a result of the feedback control described above, the phenomenon of hysteresis in the generated displacement almost disappears, and the generated displacement changes substantially linearly with respect to the input current. Thus, in the giant magnetostrictive actuator 1, hysteresis compensation is performed with a simple configuration.

  The giant magnetostrictive material exhibits a hysteresis characteristic in the change of the generated magnetic flux with respect to the change of the input voltage and the change in the generated displacement of the output end with respect to the change of the generated magnetic flux, and the hysteresis characteristic between the former input voltage and the generated magnetic flux is The latter appears remarkably compared to the hysteresis characteristics between the generated magnetic flux and the generated displacement. In the giant magnetostrictive actuator 1, the former hysteresis is eliminated, and the hysteresis remaining slightly in FIG. 2 is considered to be due to the latter.

FIG. 4 shows a giant magnetostrictive actuator 2 according to a second embodiment of the present invention. As a magnetostriction detecting means, the giant magnetostrictive actuator 2 is different from the above-described giant magnetostrictive actuator 1 in place of the magnetostrictive detection coil 16 and a Hall element. Except for the point of using 16a, the other parts are substantially the same, and the parts corresponding to each part in FIG.
In this giant magnetostrictive actuator 2, a Hall element 16 a is interposed in the middle of the rod member 11, and an electric signal due to an electromotive force generated as a result of the change in magnetic flux from the Hall element 16 a, that is, the time change rate of the magnetic flux. An electric signal whose voltage changes in proportion is output to the integrator 31.

FIG. 5 shows a giant magnetostrictive actuator 3 according to a third embodiment of the present invention. This giant magnetostrictive actuator 2 is different from the giant magnetostrictive actuator 1 described above except that the arrangement position of the permanent magnet 15 is different. Parts that are substantially the same and correspond to each other in FIG. 1 are assigned the same reference numerals and description thereof is omitted.
In this giant magnetostrictive actuator 3, ring-shaped permanent magnets 15 are provided at both ends of the drive coil 14. Similarly to the above, a movable support member that applies a magnetic bias to the rod member 11 and contacts the rod member 11. Bias displacement is applied to 13 output end portions 23 in advance.

The permanent magnet 15 only needs to be able to apply a magnetic bias to the rod member 11 and is not limited to the position and shape described above.
Moreover, in each embodiment mentioned above, although the example which used the disc spring 17 as an elastic member was shown, the elastic member is sufficient if it makes the movable support member 13 contact | abut to the rod member 11, and the disc spring 17 is sufficient. It is not limited.

  The giant magnetostrictive actuators 1 to 3 according to the present invention are used in, for example, a fine precision machining device, a sound wave oscillation source, an active vibration isolation device, and the like.

It is a figure which shows the outline of the whole structure of the giant magnetostrictive actuator which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between the input electric current and generation | occurrence | production displacement in the giant magnetostrictive actuator shown in FIG. It is a figure which shows the relationship between an input electric current at the time of removing the coil for magnetic flux detection from the giant magnetostrictive actuator shown in FIG. It is a figure which shows the outline of the whole structure of the giant magnetostrictive actuator which concerns on 2nd Embodiment of this invention. It is a figure which shows the outline of the whole structure of the giant magnetostrictive actuator which concerns on 3rd Embodiment of this invention.

Explanation of symbols

1, 2, 3 Giant magnetostrictive actuator 11 Rod member 12 Fixed support member 13 Movable support member 14 Driving coil 15 Permanent magnet 16 Magnetic flux detection coil 16a Hall element 17 Belleville spring 18 Casing 19 Control unit 21 Flange (fixed support member)
22 Flange (movable support member)
23 Output end 24 Opening 31 Integrator 32 Adder 33 Driver 41 Power supply

Claims (6)

A rod member made of a giant magnetostrictive material;
A fixed support member having a flange portion made of a magnetic material and arranged in contact with one end of the rod member;
An output end portion having a flange portion made of a magnetic material, disposed in contact with the other end portion of the rod member, and integrally displaced with the other end portion on the side opposite to the other end side A movable support member projecting
A cylindrical driving coil located between the flanges and arranged to surround the outside of the rod member;
A permanent magnet located between the flange portions and disposed near the rod member to which a bias magnetic field for extending the rod member can be applied to the rod member;
Magnetic flux detection means for outputting an electrical signal whose voltage changes in proportion to the time change rate of magnetic flux passing through this position at a position inside the driving coil;
A hollow having an opening at one end, containing the rod member, fixed support member, movable support member, driving coil, permanent magnet, and magnetic flux detection means, and having the output end located in the opening. A casing,
Including an integrator, an adder, and a driver, wherein the integrator outputs an electric signal proportional to the magnetic flux obtained by integrating the voltage of the electric signal from the magnetic flux detection means, The adder receives an electric signal corresponding to the target displacement amount of the output end from the outside, and an electric signal having a voltage component obtained by subtracting the voltage component of the electric signal from the integrator from the voltage component of the electric signal. And the driver includes a control unit configured to guide the current that fluctuates in response to the voltage fluctuation of the electrical signal from the adder from the power source to the driving coil. Giant magnetostrictive actuator.   2. The giant magnetostrictive actuator according to claim 1, wherein the magnetic flux detection means is a magnetic flux detection coil disposed around the rod member.   2. The giant magnetostrictive actuator according to claim 1, wherein the magnetic flux detecting means is a Hall element disposed in an intermediate portion of the rod member.   4. The giant magnetostrictive actuator according to claim 1, further comprising an elastic member that constantly urges the flange portion of the movable support member in a direction toward the drive coil. 5.   The giant magnetostrictive actuator according to any one of claims 1 to 4, wherein the permanent magnet is provided on an outer peripheral portion of the driving coil. The giant magnetostrictive actuator according to any one of claims 1 to 4, wherein the permanent magnets are provided at both ends of the driving coil.

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