CN108354588B - A mechanical structure of a microrobot for exploring the mechanical properties of human skin - Google Patents

Abstract

The invention discloses a mechanical structure of a micro-robot for exploring the mechanical properties of human skin. There are multiple brakes, the brake includes an outer ring and an inner ring, the outer ring is fixed on the base a, the inner ring can rotate and move up and down in the outer ring; the outer circumference of the base a is evenly fixed with a plurality of ball sliding groups, the ball The sliding group includes an outer layer and an inner layer. The outer layer is fixed on the base a, and the bottom end of the inner layer is fixed on the inner ring of the brake, and moves up and down together with the inner ring of the brake. The inner layer of the ball sliding group is provided with a displacement Sensing, the present invention uses the brake to drive the probe fixed platform to move up and down, so that the probe produces continuous deformation on the skin, and then with the help of the data measured by the sensor and the finite element structure analysis method, it can be used to accurately analyze the skin. Anisotropy, viscoelasticity, nonlinearity and other characteristics.

Description

A mechanical structure of a microrobot for exploring the mechanical properties of human skin

technical field

The invention relates to the technical field of micro-robots used for exploring the mechanical properties of human skin, in particular to a mechanical structure of a micro-robot for exploring the mechanical properties of human skin.

Background technique

The research on biological characteristics of skin tissue not only helps doctors to determine whether the skin tissue has lesions, but also can effectively optimize the surgical plan and improve the safety of the operation. In the early days, the measurement of skin mechanical properties mostly used in vivo biomechanics. In the living state, the human body was anesthetized, and the skin properties were directly measured with medical instruments. This method does not take into account the anisotropy of skin tissue and the effects of nerves, body fluids, metabolism, physicochemical environment, etc. on the mechanical properties of the skin.

With the continuous improvement of modern mechanical property measurement methods, various biomechanical test methods are widely used in skin mechanics research. During the dynamic response process, the mechanical properties parameters of the skin tissue are obtained by using the data of the points measured by the sensor and numerical methods. Researchers have conducted a lot of research on generating appropriate displacement on the surface of skin tissue and using the dynamic relationship between the displacement and the load to obtain the mechanical properties of the skin. In the article "A structure theory for the homogeneous biaxial stress-strain relationships in flat collagenoustissues", scientist Lanir proposed to perform a two-dimensional tensile test on the abdominal skin, that is, applying force to the skin in two mutually perpendicular directions to generate deformation. The device It is inconvenient to use and can only measure the skin vertically or horizontally.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a mechanical structure of a micro-robot for exploring the mechanical properties of human skin. Data and finite element analysis method can accurately analyze the anisotropy, viscoelasticity, nonlinearity and other characteristics of the skin.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is:

A mechanical structure of a micro-robot for exploring the mechanical properties of human skin, including a motion control part, a probe fixing platform part and a probe steel frame structure part, wherein the motion control part includes a base a, and a plurality of a brake, the brake includes an outer ring and an inner ring, the outer ring is fixed on the base a, the inner ring can rotate and move up and down in the outer ring; a plurality of ball sliding groups are evenly fixed on the outer circumference of the base a, and the ball sliding group It includes an outer layer and an inner layer, the outer layer is fixed on the base a, the bottom end of the inner layer is fixed on the inner ring of the brake, and moves up and down together with the inner ring of the brake, and the inner layer of the ball sliding group is provided with a displacement sensor , the top of the inner layer is provided with a positioning pin;

The probe fixing platform part includes a base b, and the bottom surface of the base b is provided with a guide column, and by arranging the positioning pin in the guide column, the motion control part and the probe fixing platform part are connected together; Connect the magnets of the steel frame structure of the probe, and the displacement sensors are evenly arranged around the magnets;

The structural part of the probe steel frame includes a base c that is connected with the magnet, a support column is arranged on the top surface of the base c, the top surface of the support column is connected to the probe, the top surface of the probe is provided with a biomechanical sensor, and the top surface of the support column is provided with a biomechanical sensor. Reinforcing ribs are evenly distributed on the outer circumferential surface, and the reinforcing ribs are in contact and connected with the displacement sensor on the base b.

Preferably, the base a is a hexagonal prism-shaped rigid body structure, and the base a has six side planes, which is convenient for positioning and installing the ball sliding group.

Further preferably, there are three ball sliding groups in total, the base a has six side planes, one ball sliding group is arranged at every side plane, and the three ball sliding groups are arranged in an equilateral triangle.

More preferably, there are three brakes in total, the brakes are arranged in an equilateral triangle on the base a, and the brakes are BEI-KimcoLA15 voice coil brakes.

The base b of the present invention has a cylindrical structure, and the magnet is also cylindrical. Three U-shaped chutes are arranged around the magnet in an equilateral triangle, and a displacement sensor is arranged in the chutes.

The principle of the present invention is:

In the present invention, three voice coil brakes of the same model are used to drive the inner layer of the ball sliding group to move up and down, and the three brakes can be activated simultaneously or optionally, so that the fixed platform part of the probe can obtain different spatial positions and attitudes. The three-degree-of-freedom movement or two-degree-of-freedom movement of the probe fixing platform is realized, and the probe fixing platform drives the probe steel frame structure part and the probe movement, and the probe can produce three-dimensional or two-dimensional deformation of the skin. The displacement sensor on the inner layer of the ball sliding group and the probe fixing platform measures the displacement of the probe driven by the brake, and the biomechanical sensor on the probe measures the deformation stress and strain on the skin surface. The measured data is then used to use finite element analysis to accurately obtain the anisotropy, viscoelasticity and nonlinear characteristics of human skin.

The present invention adopts the above-mentioned technical scheme to have the following technical effects:

The invention adopts the brake to drive the probe fixed platform to move up and down, so that the probe produces continuous deformation on the skin, and then with the help of the data measured by the sensor and the finite element structure analysis method, it can be used to accurately analyze the various directions of the skin. Anisotropy, viscoelasticity, nonlinearity, etc.

Description of drawings

Figure 1 is a schematic diagram of the structure of the motion control part.

FIG. 2 is a schematic structural diagram of the part of the probe fixing platform.

FIG. 3 is a top view structure of FIG. 2 .

FIG. 4 is a schematic structural diagram of the structural part of the probe steel frame.

FIG. 5 is a schematic diagram of the overall structure of the present invention.

Specific implementation method

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 5 , the mechanical structure of a micro-robot for exploring the mechanical properties of human skin according to the present invention includes a motion control part, a probe fixing platform part and a probe steel frame structure part.

As shown in Fig. 1, the motion control part includes a base a1, a plurality of brakes 2 are fixed on the base a, the brake includes an outer ring and an inner ring, the outer ring is fixed on the base a, the inner ring can rotate in the outer ring and Move up and down; a plurality of ball sliding groups 3 are evenly fixed on the outer circumference of the base a, the ball sliding group includes an outer layer 4 and an inner layer 5, the outer layer is fixed on the base a, and the bottom end of the inner layer is fixed on the inner ring of the brake It moves up and down with the inner ring of the brake. A displacement sensor is arranged on the inner layer of the ball sliding group; a positioning pin 6 is arranged at the top of the inner layer.

In this embodiment, the base is preferably a hexagonal prismatic rigid body structure.

There are three ball sliding groups in this embodiment, the hexagonal prism base has six side planes, and a ball sliding group is arranged at every side plane, and the three ball sliding groups are arranged in an equilateral triangle. The ball sliding group has an existing structure, and in this embodiment, the Japanese IKO linear guide BSP1035 SL is preferred.

There are three brakes in this embodiment. The brakes are arranged in an equilateral triangle on the base. The brakes are in the prior art. In this embodiment, the BEI-KimcoLA15 voice coil brake is preferred, which can generate a displacement greater than 3mm and a frequency greater than 100Hz. The action precision is high. The brake includes an outer ring and an inner ring, the outer ring is fixed on the base, and the inner ring can rotate and move relatively up and down in the outer ring.

In this embodiment, three displacement sensors are placed on the inner layer of the ball sliding group to dynamically measure the up and down displacement of the inner ring of the brake during movement, so as to analyze the control of the robot's working vertex, and the voltage output by the displacement sensor can be calculated. The displacement of the inner ring of the brake. In this embodiment, a photodiode sensor is selected, preferably SG-2BC from KODENSHI Company of Japan, which has the advantages of high measurement accuracy and low price. The photodiode sensor is installed on the inner layer of the ball sliding group, the light emitted by the light emitting diode is injected into the plastic optical fiber, and the free end of the optical fiber is installed on the moving part of the brake, so that the photodiode can be illuminated. The use of plastic optical fibers can effectively control the direction of light, and no other equipment needs to be installed on the inner layer of the ball sliding group. A microscope is attached to the end of the fiber so that it can focus all of the light onto the photodiode.

As shown in Figures 2 and 3, the probe fixing platform part includes a base b7, and the bottom surface of the base b is provided with a guide post 8. By arranging the positioning pin in the guide post, the motion control part and the probe fixing platform part are connected together ; The top surface of the base b is provided with a magnet 9 for connecting the structural part of the probe steel frame, and a displacement sensor 10 is evenly arranged around the magnet.

Both the displacement sensor arranged around the magnet and the displacement sensor on the inner layer of the ball sliding group can be used to measure the displacement of the probe. Simply using the displacement sensor on the inner layer of the ball sliding group to measure the displacement of the probe will be affected by the difference between the structural parts. Installation and relative sliding cause errors, so a displacement sensor is installed on the base b.

As shown in FIG. 3 , in this embodiment, the base b is preferably a cylindrical structure, and the magnet is also cylindrical. Three U-shaped chute 11 are arranged around the magnet in an equilateral triangle, and a displacement sensor is arranged in the chute. There is a one-to-one correspondence between the movement of the brake and the movement of the probe. The brake is placed in an equilateral triangle shape, so the displacement sensor is also placed in the same way, which can more accurately measure the displacement of the probe in all directions.

Both the base a and the base b are made of light and rigid materials to reduce inertia, so as to reduce the elastic deviation generated when the inner ring of the brake rotates with the probe moving up and down. In addition, it is necessary to consider preventing the working frequency of the base and the brake from resonating.

As shown in FIG. 4 , the probe steel frame structure part includes a base c12 which is attached to the magnet by adsorption. A support column is provided on the top surface of the base c. The top surface of the support column is connected to the probe 13, and the top surface of the probe is provided with a For the biomechanical sensor, reinforcing ribs 14 are evenly distributed on the outer circumferential surface of the support column, and the reinforcing ribs are in contact with the displacement sensor on the base b. The reinforcing rib can provide rigid strength to the support column of the probe, and prevent distortion and deformation caused by uneven stress distribution of the support column due to the extrusion of the probe and the skin.

The probe is in contact with the skin. In order to reduce the damage of the probe to the skin, the contact surface of the probe can be designed in a circular shape. When the brake is activated, the probe is driven to move, thereby displacing the skin surface.

In this embodiment, the reinforcing rib has a right-angled trapezoid structure, and the hypotenuse of the reinforcing rib is inclined from the outer circumference of the support column to the base c. The design of the reinforcing rib in a right-angled trapezoid is mainly to avoid stress concentration, and the trapezoid can provide greater supporting force and is more beautiful. .

The above-mentioned biomechanical sensors can be selected from sensors independently developed and designed by the applicant, or commercial sensors such as the American AMTI six-dimensional force sensor.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention.

Claims (5)

1. A mechanical structure of a micro robot for researching mechanical characteristics of human skin is characterized by comprising a motion control part, a probe fixing platform part and a probe steel frame structure part, wherein the motion control part comprises a base a, a plurality of brakes are fixedly arranged on the base a, each brake comprises an outer ring and an inner ring, the outer ring is fixed on the base a, and the inner ring can rotate in the outer ring and can move up and down; a plurality of ball sliding groups are uniformly and fixedly arranged on the periphery of the base a, each ball sliding group comprises an outer layer and an inner layer, the outer layer is fixed on the base a, the bottom end of the inner layer is fixed on the inner ring of the brake and moves up and down along with the inner ring of the brake, a displacement sensor is arranged on the inner layer of each ball sliding group, and a positioning pin is arranged at the top end of the inner layer;

the probe fixing platform part comprises a base b, a guide post is arranged on the bottom surface of the base b, and the motion control part and the probe fixing platform part are connected together by arranging a positioning pin in the guide post; the top surface of the base b is provided with a magnet for connecting with the probe steel frame structure part, and displacement sensors are uniformly arranged around the magnet;

the probe steel frame structure part comprises a base c which is connected with the magnet in an adsorption mode, a supporting column is arranged on the top surface of the base c, the top surface of the supporting column is connected with the probe, a biomechanics sensor is arranged on the top surface of the probe, reinforcing ribs are uniformly distributed on the outer circumferential surface of the supporting column, and the reinforcing ribs are in contact connection with the displacement sensor on the base b.

2. The mechanical structure of the micro-robot for researching mechanical characteristics of human skin as claimed in claim 1, wherein the base a is a hexagonal prism-like rigid body structure.

3. The mechanical structure of the micro-robot for studying mechanical properties of human skin as claimed in claim 2, wherein there are three ball sliding sets, the base a has six side planes, one ball sliding set is disposed every other side plane, and the three ball sliding sets are disposed in an equilateral triangle.

4. The mechanical structure of the micro-robot for researching mechanical characteristics of human skin as claimed in claim 3, wherein there are three brakes, the brakes are disposed on the base a in an equilateral triangle, and the brake is BEI-Kimcola15 voice coil type brake.

5. The mechanical structure of the micro-robot for studying mechanical properties of human skin as claimed in claim 1, wherein the base b is a cylinder, the magnet is also a cylinder, three U-shaped chutes are disposed around the magnet in an equilateral triangle, and the chutes are disposed with displacement sensors.

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