LT6728B - Magnetic piezoelectric driver device - Google Patents

Abstract

This description provides a technical solution for orienting, turning and positioning in the space of small spacecrafts. A device is provided, which operation is based on the piezoelectric effect. The device comprises a mechanical part and an electrical part. The principle of the device's operation consists of vibrations created by preset electrical signals, affecting piezoelectric elements. The vibrations generate and transmit the motion to a spherically shaped magnet (rotor) having one pair of poles (north and south). The shape and the position of the piezoelectric transducers relative to the rotor allow the rotor to be rotated around its center to the required direction. The device is characterized by extremely high precision positioning resolution and speed, efficient electric energy consumption, uncomplicated construction, no bearing junctions are present (which increases the reliability of operation). The device occupies a small space, making it easy to apply for positioning of small and nano-spacecrafts. The device’s holding, case structures are easilly integrated into the spacecraft structure. The device does not generate an electromagnetic noise.

Description

TECHNICAL FIELD

The invention belongs to the field of piezoelectric actuators, and more particularly to the use of a piezoelectric element for rotating a magnetic rotor. The described device can be used for space orientation of small objects, orientation and positioning systems of small, nano-type satellites when the satellite is in space and the like.

BACKGROUND OF THE INVENTION

There is a known device in which a permanent magnet is mounted in an articulated system with an electromechanical drive, which allows to change the angular position of the magnet in space. To change the orientation of the nanosatellite or position it in space, electric motors are rotated, which rotate the permanent magnet accordingly. In this way, the satellite is exposed to the Earth's magnetic field and the proper orientation of the permanent magnet is tilted in the desired direction (Rex A. Bair. Gimbaled Permanent Magnet-Based Attitude Control for Pico / Nano Satellites, The University of Arkansas, USA, 2011). Such a system takes up a lot of space. Compared to a permanent magnet, electric motors, shafts, rotating mechanisms, sensors and housing occupy the largest share of the total volume of the device. Accordingly, as the dimensions of the device increase, so does its mass, which degrades the efficiency of such a satellite guidance and positioning system.

US5476018 (published December 19, 1995) discloses a device with an electromagnetic drive in which the driving motion is performed by magnetic fields rotating a spherical rotor. The operation of the system is based on the fact that the spherical rotor is mounted on the frame and electromagnets are placed around it. The generated controlled magnetic field rotates the rotor in the desired direction. This creates a mechanical, gyroscopic moment. In the specified device, the rotor is mounted using spherical hydrostatic bearings. Operating such a device requires a lot of energy and generates a lot of electromagnetic noise. Such drives are difficult to integrate in small volumes, making them difficult to use in small satellites due to local and energy resources.

Summarizing the above state-of-the-art documents, the following shortcomings can be identified:

- the appliance uses a lot of electricity and is not energy efficient,

- the device generates a lot of electromagnetic noise,

- the device is complex, almost impossible to adapt to small devices such as nanosatellites,

- a complex, multi-component system, which reduces efficiency and reliability.

The technical solution presented in this description does not have the shortcomings listed above.

SUMMARY OF THE INVENTION

This description provides a technical solution for the orientation, rotation, and orientation of small spacecraft in space. A device based on the piezoelectric effect is presented. the device consists of a mechanical part and an electrical part. The essence of the principle of operation of the device consists of the oscillations generated by the piezoelectric elements exposed to the determined electrical signals, which generate and transmit the motion to a spherical magnet (rotor) having one pair (north and south) of poles. The selected piezoelectric shape of the transducers and their position relative to the rotor allow the rotor to be rotated about its center in the required direction.

The device is characterized by extremely high precision positioning resolution and speed, efficient use of electricity, uncomplicated construction, no bearing units (which increases operational reliability). The device takes up little space, making it easy to target for small and nano-spacecraft. The supporting, hull structures of the device are easily integrated into the structure of the spacecraft. The device does not generate electromagnetic noise.

BRIEF DESCRIPTION OF THE DRAWINGS fig. depicts a schematic diagram of a piezoelectric device.

fig. depicts a piezoelectric transducer with elastic gaskets and support elements and its control scheme.

The numbers in the pictures are marked:

- elastic gasket; 2 - piezoelectric transducer (piezoelectric transducer); 3 - rotor; 4 support element; 5 - flange; 6 - piezoelectric converter undivided electrode; 7 piezoelectric transducer divided into 3 level segments every 120 °; 8 - screw, 9 3 electrode divisions; 10 - signal generator; 11 - control unit.

BEST MODES FOR IMPLEMENTATION

The object of the invention is to create a drive for continuous rotation of a magnet in space, with the help of which it would be possible to position and orient a nano-type satellite in space. This system must also not emit electromagnetic noise. Advantages of such a drive: high resolution and speed, simple construction.

The object of the invention is achieved in that in a piezoelectric device consisting of a mechanical and an electrical part, a rotor of a spherical permanent magnet is placed between two piezoelectric rings, which allow the rotor to rotate and allow its angular position in space to be changed.

The mechanical part of the device consists of:

- rotor (3) - a magnetic ball with one pair (north and south) of poles,

- a stator consisting of two annular piezoelectric transducers (2) between which the rotor (3) is housed, the transducers (2) being arranged on opposite sides of the rotor (3),

- a housing consisting of a flange (5) and bolts (8) and other components.

As mentioned, the stator consists of two piezoelectric transducers (2) resembling a ring in their shape.

The piezoelectric transducer (2) has two electrodes (6) and (7) arranged on opposite sides of it, one of which is continuous (6) and the other (7) divided into 3 equal segments every 120 °. A support element (4) is attached in the middle of each of the three said segments. The support element (4) is made of abrasion-resistant material. With these support elements (4), the piezoelectric transducer rests on the rotor (3). An elastic gasket (1) is attached to the side of each support element (4) other than the rotor (3). All elastic gaskets (1) are arranged on the piezoelectric transducer (2) every 120 °, in the division points (9) of the electrode (7).

The housing of the device consists of two flanges (5), to which piezoelectric transducers (2) are attached via elastic seals (1). The flanges (5) with the attached piezo changers (2) and the rotor (3) placed between them are connected by screws (8) which ensure proper tightening and contact of the support elements (4) of both piezo changers (2) with the rotor (3).

The piezoelectric transducers (2) are arranged opposite each other on opposite sides of the rotor (3) and are positioned concentrically, and the points of contact of their support elements (4) with the surface of the rotor (3) are in a line passing through the center of the rotor (3). in front of each support element (4) of one piezoelectric converter (2) on the opposite side of the rotor (3) there is one of the support elements (4) of the other piezoelectric converter (2). The control electrodes of the piezoelectric transducers (2) are connected as follows: the undivided piezoelectric transducer electrodes (6) are interconnected and connected to the zero channel 0 of the control unit (11), and the piezoelectric transducer divided electrodes (7) on diametrically opposite sides of the rotor (3) and each pair of split electrodes (7) is connected to the three phase channels A, B and C of the control unit (11) (Figure 2).

The electrical part of the device comprises a harmonic signal generator (10) and a control unit (11) which are electrically connected to the piezoelectric transducer electrodes (6) and (7).

device rotor (3) - a permanent spherical magnet with one pair (north and south) of poles - sandwiched between two ring-shaped piezoelectric transducers (2) located on opposite sides of the rotor and in contact with the rotor (3) through support elements (4) ). Each piezoelectric transducer (2) has two electrodes arranged on opposite sides of it, one of which is continuous (6) and the other (7) every 120 °, divided into 3 equal segments (division points (9)). In the middle of each of the three segments there is a support element (4) (made of abrasion-resistant material). On the side of the piezoelectric transducer (2) other than the rotor (3), where the undivided electrode (6) is located, 3 elastic gaskets (1) are arranged, spaced every 120 °, at the splitting points (9) of the electrode (7).

An electrical signal of a certain amplitude and frequency is fed from a harmonic signal generator (10) to a control unit (11), which transmits this signal to one of the three split electrodes (7), thus generating high frequency three-dimensional oscillations in the piezoelectric transducers (2). These oscillations force the two support elements (4) on opposite sides of the rotor (3) to move in elliptical trajectories. The moving support elements (4) transmit and generate the rotational movement of the rotor (3) around their center due to friction. The support elements (4) with the rotor (3) form a kinematic pair in which the elliptical movements generated by the support elements (4) are transformed into a directional rotational movement of the rotor (3). When the control unit (11) sends an electrical signal to another pair of split piezoelectric transducer electrodes (7), the oscillations of the other support elements (4) are excited and the rotor (3) changes the direction of rotation. If a three-phase electrical signal of a certain frequency (Usin (© t), Usin (<ot + I20 °) and Ucos (© t + 240 °) is supplied simultaneously in the phase channels (A, B and C) of the control unit (11), in piezoelectric converters the oscillations of the traveling wave will be excited, which will generate a directional rotation of the rotor (3) about a vertical axis.To change the direction of rotation of the rotor (3) (the direction of propagation of the wave in the piezoelectric transducer (2)), two electrodes of the piezoelectric transducer (2) the signals are exchanged in places such as j Usin (wt + l20 °) phase voltage applied to the Usin (rat) phase voltage electrode and vice versa Usin (ot) phase voltage applied to the Usin (wt + l20 °) phase voltage electrode.

In order to illustrate and describe the present invention, the most preferred embodiments are described above. It is not an exhaustive or restrictive description intended to determine the exact form or embodiment. The above description should be considered as an illustration rather than as a limitation. Obviously, many modifications and variations can be apparent to those skilled in the art. An embodiment is selected and described so that those skilled in the art can best understand the principles of the present invention and their best practice for different embodiments with different modifications appropriate to the particular use or application. It is intended that the scope of the invention be defined by the definition appended thereto and its equivalents, in which all the above terms have the broadest meaning, unless otherwise indicated.

Modifications may be made to the embodiments described by those skilled in the art without departing from the scope of the present invention, as defined below.

Claims (5)

DEFINITION OF THE INVENTION A magnetic piezoelectric device comprising a magnetic rotor and a stator connected to a multiphase harmonic signal generator (10), characterized in that the magnetic rotor (3) having one pair (north and south) of poles is sandwiched between two ring-shaped piezoelectric transducers (2), which are arranged on opposite sides of the rotor (3) and contact the rotor (3) via support elements (4). 2. Magnet piezoelectric device according to claim 1, characterized in that the support elements (4) with the rotor (3) form a kinematic pair in which the elliptical movements generated by the support elements (4) are transformed into a directional rotational movement of the rotor (3). 3. Magnet piezoelectric device according to claim 1, characterized in that the device does not use bearing supports for positioning the rotor (3), which significantly simplifies the construction of the whole system and eliminates possible positioning accuracy errors. 4. Magnetic piezoelectric device according to claim 1, characterized in that the stator of the device consists of two annular piezoelectric transducers (2), each with 3 support elements (4) attached and arranged concentrically on opposite sides of the rotor 3 and their support elements ( 4) the points of contact with the surface of the rotor (3) are in a line passing through the center of the rotor (3), ie in front of each support element (4) of one piezoelectric converter there is one of the support elements (4) of the other piezoelectric converter on the opposite side of the rotor. A magnet piezoelectric device according to the preceding claims is used for orienting, rotating and guiding small, nano-type spacecraft in space.