KR20100006831A - Micro multi-dof manipulator - Google Patents

Abstract

PURPOSE: A multi-DOF micro manipulator is provided to perform high precision operation control by employing a multilayered piezoelectric actuator using a PMN-PT(PbMgNbO3-PbTiO3) monocrystal piezoelectric element. CONSTITUTION: A first moving object(120) is installed to move up and down within a horizontal path. A second moving object(130) is perpendicular to the first moving object and slides upward with friction. The second moving object is installed to move up and down within an upper path on a micro stage(110). A micro-processor applies power in the first and second moving objects. A first and a second PMN-PT multilayered piezoelectric actuator(140,150) are extended/restored by the micro-processor. A tip element(160) is operated by the fist and the second multilayered piezoelectric actuator.

Description

Multi-DOF Manipulator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromanipulator having multiple degrees of freedom, in particular three degrees of freedom, using a multilayer actuator made by stacking PMN-PT (PbMgNbO3-PbTiO3) single crystal single plates.

In general, robots used in industry are largely classified into two types: manipulators and mobile robots. First of all, the manipulator has functions such as moving objects with multiple arms or assembling them using end-effectors, and mobile robots autonomously avoid obstacles and move objects along a given path. To perform. The manipulator robot may have joints of rotational or linear motion, and the degrees of freedom determine the motion of the linked links. Mobile robots move freely with sensors and actuators to change positions.

In the field of ultra-precision, piezoelectric materials have been researched and developed in various fields to construct linear actuators. Recently, various kinds of ultra-precision piezoelectric actuators have been commercialized. Actuators using intelligent materials with higher power densities than conventional actuators have been studied in many fields in recent decades. These research fields are diverse, such as vibration control, acoustic control, position control, and fluid control. In particular, actuators using piezoelectric materials have fast response speeds and are capable of ultra-precision movement, and have been applied to various fields of ultra-precision processing and control.

However, the piezoelectric material used in most piezoelectric actuators is PZT (Pb (Zr, Ti) O3), which has a structure including a mechanical amplifier to be used as an actual linear actuator due to the limitation of low displacement and low power. The reality is that it is being applied.

In addition, in the system requiring more precise control and quick response due to the inclusion of such additional devices, it is difficult to perform ultra-precision control by generating various hysteresis and time delay phenomena.

Compared to conventional PZT ceramics, PMN-PT shows six times the displacement under the same measurement conditions. Therefore, piezoelectric single crystal materials are highly applicable to camera phones.

In addition, due to the high piezoelectric coefficient and electromechanical coupling coefficient of the piezoelectric single crystal, it is known that the piezoelectric single crystal exhibits excellent performance in the medical ultrasound field.

In particular, heart probes using piezoelectric single crystals provide high sensitivity to capture blood flow that cannot be found with conventional PZT ceramics.

The basics of the manipulator are three-dimensional coordinate transformation, kinematics of multiple joints, sensors and actuators, etc. In such manipulators, the piezoelectric material used in most piezoelectric actuators as operating actuators is PZT (Pb (Zr, Ti). In reality, it is applied to a structure including a mechanical amplifier to use as a linear actuator due to the limitation of low displacement and low power.

More specifically, low displacement low power problems of PZT-based piezoelectric materials, energy loss and disadvantages of ultra-precision control due to the application of amplification mechanisms, super-precision control when mechanical friction occurs in micro-units, and small force from the outside during ultra-precision operation Equipped with the disadvantages, such as the impossibility of precise operation.

In addition, in the system requiring more precise control and quick response due to the inclusion of such additional devices, it is difficult to perform ultra-precision control by generating various hysteresis and time delay phenomena.

The present invention to achieve the above object, in order to overcome the existing problems, based on the multi-layered actuator using the PMN-PT single crystal, considering the friction of the micro unit, a robust friction algorithm to propose and control a new friction model The main technical challenge is to develop a smart micro manipulator system with multiple degrees of freedom, especially three degrees of freedom.

In other words, in the present invention, by applying a laminated piezoelectric actuator using a PMN-PT single crystal piezoelectric element, high precision motion control can be performed in a fine range, and three degrees of freedom (three axes) that are robust to external resistance elements and stick-slip friction phenomenon Its main purpose is to provide a manipulator device.

The multiple degree of freedom micro manipulator according to the present invention for realizing the above object,

A tri-axial micro stage serving as an expectation,

A first movable body mounted on the micro-stage to be movable up and down in the horizontal path so as to be slidably moved in friction with the horizontal direction;

A second movable body mounted on the micro stage so as to be lifted and lowered in the upward path so as to be in sliding contact with the first movable body perpendicularly and frictionally in an upward direction;

First and second PMN-PT laminated piezoelectric actuators which can be extended and restored by a controller for applying power in the first and second moving bodies;

And end devices actuated by the first and second PMN-PT laminated piezo actuators.

In addition, the first moving body is interposed between the L-shaped first moving block fixedly disposed on the micro stage, the second moving block and the first and second moving blocks arranged in a line symmetry with the first moving block. It is preferred that the first PMN-PT laminated piezoelectric actuator is configured.

The second movable body may further include an L-shaped third moving block arranged orthogonally to an L-shaped second moving block fixedly disposed on the micro stage, and a third movement arranged in line symmetry with the third moving block. It is preferable that the second PMN-PT laminated piezoelectric actuator is interposed between the block and the third and fourth moving blocks.

In addition, it is preferable that end points of the first and second moving bodies and the micro stage are arranged to be in direct contact with the zero-adjustment micrometer head so as to directly contact the first and second PMN-PT laminated piezo actuators.

As described above, the micro manipulator according to the present invention may be used in biotechnology such as a microscopic injection into a cell, a nucleus or the like removed from a cell, etc. According to the trend of high performance and miniaturization of related parts, it can be applied to ultra-precision intelligent robots used in the production process of these fields, and also applied as a manipulator in MEMS field and other industries to manufacture precision parts, semiconductor industry equipment, micro robots, and games. It can be used for simulation, automobile driving simulation, nuclear waste treatment equipment, next-generation computer interface, and in the medical industry, it can be applied as a manipulator device for medical devices that need high precision control such as medical instruments and medical procedure simulation equipment. It can reduce foreign exchange expenditure of royalties due to alcohol use, and which would have an excellent effect of transplantation of ovarian nuclear extracts of the biotechnology industry and the stem cells are applied to enable research equipment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, a multi-degree of freedom micromanipulator according to the present invention includes a tri-axial micro stage 110 serving as a base and a horizontal direction on the micro stage 110. On the micro-stage 110, the first movable body 120 mounted on the horizontal path so as to be slidably moved in frictional contact with the first movable body 120 is in frictional contact with the first movable body 120 in an upward direction. Extendable and restorable by a second movable body 130 mounted in the upward path so as to be slidably movable, and a controller 300 for applying power in the first and second movable bodies 120 and 130. First and second PMN-PT laminated piezoelectric actuators 140 and 150 and end devices 160 operated by the first and second PMN-PT laminated piezoelectric actuators 140 and 150.

In addition, the end device 160 is a joint type fixed to one side of the second PMN-PT laminated piezoelectric actuator 150 to be operated by the first and second PMN-PT laminated piezoelectric actuators (140, 150). The fixed block 161 and an end effector 163 inserted into and fixed to the fixed block 161 are provided.

In addition, the first moving body 120 is an L-shaped first moving block 121 and a second moving block arranged in a line symmetry with the first moving block 121 is fixedly disposed on the micro stage 110 horizontally. 123 and the first PMN-PT laminated piezoelectric actuator 140 interposed between the first and second moving blocks 121 and 123.

In addition, the second moving body 130 is an L-shaped third moving block 131 arranged orthogonally to the L-shaped second moving block 123 fixedly disposed on the micro stage 110, and the first It consists of a third moving block 131 arranged in a line symmetry with the third moving block 131 and a second PMN-PT laminated piezoelectric actuator 150 interposed between the third and fourth moving blocks (131, 133). .

In addition, zero-adjustment micrometer heads 200 are connected to ends of the first and second moving bodies 120 and 130 to directly contact the first and second PMN-PT laminated piezoelectric actuators 140 and 150. It is arranged to

At this time, the user's willingness to operate is transmitted to the control unit 300 (Micro-processor) through a joystick-shaped handle, and the operation signal that has undergone the processing using the robust control algorithm drives the piezoelectric actuator to perform fine ultra-precision motion control. .

At this time, the stick-slip phenomenon at the contact portion of the stage should be suppressed in order to achieve high precision motion control.

This stick-slip phenomenon is indispensable in most mechanical contact systems, especially in micro-unit systems.

Therefore, this study derives stick-slip friction model using statistical rough surface contact model and performs ultra-precise manipulation control for modeling accuracy of stick-slip friction phenomenon.

This statistical surface roughness contact model is constructed by measuring the surface roughness of the friction part of the actual device, enabling accurate modeling of the stick-slip phenomenon and ultra-precision control.

In addition, robust manipulators such as sliding mode controllers are integrated to control the entire manipulator device for accurate end-effector positioning.

Therefore, in the present invention, unlike the PZT piezoelectric actuator method, the PMN-PT single crystal actuator having a large displacement amount has a larger displacement amount, and a new statistical surface roughness contact model is used to propose a more accurate friction model, and compensate by using the same. Through the algorithm, it has a hierarchical form to control the force caused by contact of the working environment and enable fine fine operation, and it is possible to ensure effective work performance in ultra-precision work through a control algorithm robust to external influences.

As described above, according to the multi-degree-of-freedom micro manipulator according to one embodiment of the present invention, when a piezoelectric micro manipulator is developed using PMN-PT single crystal piezoelectric material, PZT piezoelectric micro The disadvantages of the manipulator can be compensated for, so that higher ultra-precision control can be achieved.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a perspective view showing a main body of a multiple degree of freedom micro manipulator according to an embodiment of the present invention.

FIG. 2 is a longitudinal cross-sectional view of the entirety of the components of the multiple degree of freedom micro manipulator of FIG. 1.

Explanation of symbols on the main parts of the drawings

 100: manipulator

 110: micro stage

 120: first moving body

 121: first moving block

 123: second moving block

 130: second mobile body

 131: third moving block

 133: fourth moving block

 140: first PMN-PT laminated piezo actuator

 150: second PMN-PT laminated piezo actuator

 160: terminal device

 200: micrometer head

 300: control unit

Claims (4)

A triaxial micro stage which serves as an expectation, A first movable body mounted on the micro-stage to be movable up and down in the horizontal path so as to be slidably moved in friction with the horizontal direction; A second movable body mounted on the micro stage so as to be lifted and lowered in the upward path so as to be in sliding contact with the first movable body perpendicularly and frictionally in an upward direction; First and second PMN-PT laminated piezoelectric actuators which can be extended and restored by a controller for applying power in the first and second moving bodies; And a terminal device operated by said first and second PMN-PT laminated piezo actuators. The method of claim 1, The first moving body may include an L-shaped first moving block fixedly disposed on the micro stage, a second moving block arranged in parallel with the first moving block, and a first interposed between the first and second moving blocks. A multiple degree of freedom micro manipulator comprising one PMN-PT laminated piezo actuator. The method of claim 2, The second moving body may include an L-shaped third moving block arranged orthogonally to an L-shaped second moving block horizontally disposed on the micro stage, and a third moving block arranged in line symmetry with the third moving block. A multiple degree of freedom micro manipulator comprising a second PMN-PT laminated piezoelectric actuator interposed between the third and fourth moving blocks. The method of claim 2 or 3, A zero degree of freedom micrometer head is connected through the end portions of the first and second moving bodies and the micro stage to be in direct contact with the first and second PMN-PT laminated piezoelectric actuators. Manipulator.

Images