Medical surgical robot flexible three-dimensional force sensor

Abstract

The application is a kind of medical operation robot flexible three-dimensional force sensor, which comprises a rigid shell (10), a rigid cross beam force transmission structure (20), a flexible film (30) and a pressure sensor; the rigid cross beam force transmission structure (20) is located in the rigid shell (10); the flexible film (30) is located in the rigid shell (10) and the upper part, the rigid shell (10), the rigid cross beam force transmission structure (20) and the flexible film (30) are coaxial; the pressure sensor is located at the bottom of the rigid shell (10). The sensor has the advantages of small size, simple structure and improved precision by using differential technology, and is suitable for multi-dimensional force measurement in the medical field.

Description

TECHNICAL FIELD

[0001] The application is a kind of medical surgical robot flexible three-dimensional force sensor, which belongs to the technical field of robot sensor design. BACKGROUND

[0002] Multi-dimensional force sensor can simultaneously perceive the force component and torque component in multiple dimensions in space, so as to obtain complete force information in complex system, and is widely used in human-computer interaction based on force touch, humanoid robot, aerospace, biomedical research, medical equipment and automobile fields. At present, the medical surgical robot puts forward urgent demand for small multi-dimensional force sensor research and application, so miniaturization becomes the primary problem faced by medical multi-dimensional force sensor.

[0003] The resistance strain type multi-dimensional force sensor based on cross beam structure is currently the most widely used, but the process limit of strain gauge makes it difficult for the sensor to achieve smaller size design. At the same time, most of the small multi-dimensional force sensors developed at present adopt MEMS processing and integrated strain gauge, resulting in high cost. Therefore, it has important practical significance to design a medical small multi-dimensional force sensor using new principle. SUMMARY

[0004] Technical problem: the purpose of the application is to design a kind of medical surgical robot flexible three-dimensional force sensor structure aiming at the problems of large volume of existing multi-dimensional force sensor, high cost of small multi-dimensional force sensor, etc., which has the advantages of small size, simple structure and high precision by using differential technology, and is suitable for multi-dimensional force measurement in medical field.

[0005] Technical scheme: the medical surgical robot flexible three-dimensional force sensor of the application comprises a rigid shell, a rigid cross beam force transmission structure, a flexible film and a pressure sensor; the rigid cross beam force transmission structure is located in the rigid shell; the flexible film is located in the rigid shell and the upper part, and the rigid shell, the rigid cross beam force transmission structure and the flexible film are coaxial; the pressure sensor is located at the bottom of the rigid shell.

[0006] The rigid shell is composed of a hollow cylindrical structure with four rectangular thin wall structures and a bottom cover; the four rectangular thin wall structures are symmetrically distributed around the inner wall of the hollow cylindrical structure; one end of the four rectangular thin wall structures is connected with the hollow cylindrical structure, and the other end is sealingly connected with the outer wall of the hollow cylindrical film in the flexible film.

[0007] The rigid cross beam force transmission structure is composed of a cross beam and a cylinder; the cross beam is composed of four rectangular beams distributed in cross shape, the top center of the cross beam is connected with one end of the cylinder, and the outer periphery of the cross beam is sealingly connected with the inner wall of the hollow cylindrical film of the flexible film; the side wall of the upper end part of the cylinder is sealingly connected with the circular film in the flexible film.

[0008] The flexible film is composed of a hollow cylindrical film and a disc film; the top end of the hollow cylindrical film is sealingly connected with the disc film, the outer wall and the bottom end of the hollow cylindrical film are sealingly connected with the rigid shell, and the inner wall of the hollow cylindrical film is sealingly connected with the cross beam of the rigid cross beam force transmission structure; five cavities are formed between the flexible film and the rigid shell, namely one cavity in the hollow cylindrical film, four cavities separated by four rectangular thin wall structures between the hollow cylindrical film and the rigid shell.

[0009] The pressure sensor comprises a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor and a fifth pressure sensor; the five pressure sensors are respectively located on the bottom cover in the rigid shell in the five cavities.

[0010] The material used for the flexible film is a silica gel material formed after natural solidification of liquid silica gel, which can bond metals and plastics and rubbers.

[0011] The preparation process of the sensor is as follows: first, the flexible film is prepared; then the rigid cross beam force transmission structure is sealingly connected with the flexible film through glue; the five pressure sensors are respectively placed in the cavities between the four rectangular thin wall structures in the rigid shell and the cavity of the flexible film; finally, the rigid shell is sealingly connected through glue.

[0012] The measurement principle of the three-dimensional force sensor is that the whole structure has five cavities in front, back, left, right and middle, and one pressure sensor is respectively placed in each cavity for cavity pressure measurement. The two cavity pressure sensors in the X direction are differentially calculated for measuring the X direction force; the two cavity pressure sensors in the Y direction are differentially calculated for measuring the Y direction force; the cavity sensor in the middle is used for measuring the Z direction force. When the force acts on the top cylinder of the rigid cross beam force transmission structure, the cross beam drives the flexible film to deform, causing the corresponding cavity pressure to change, and the force value can be obtained through the pressure change.

[0013] Advantages: compared with the existing technology, the present application has the following advantages:

[0014] (1) The medical surgical robot flexible three-dimensional force sensor designed in the present application avoids the use of strain gauges of strain type multi-dimensional force sensors, and the sensor has a small volume.

[0015] (2) The medical surgical robot flexible three-dimensional force sensor designed in the present application adopts differential technology, which improves the measurement accuracy.

[0016] (3) The medical surgical robot flexible three-dimensional force sensor designed in the present application has a simple structure and is easy to process. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1The overall structure of the present application is shown in the schematic diagram.

[0018] Figure 2 The rigid shell structure of the present application is shown in the schematic diagram.

[0019] Figure 3 The rigid cross-beam force transmission structure of the present application is shown in the schematic diagram.

[0020] Figure 4 The flexible membrane structure of the present application is shown in the schematic diagram.

[0021] Figure 5 The installation position of the pressure sensor of the present application is shown in the schematic diagram.

[0022] In the figure:

[0023] Rigid shell 10, hollow cylindrical structure 11, rectangular thin-walled structure 12, bottom cover 13;

[0024] Rigid cross-beam force transmission structure 20, cross-beam 21, cylinder 22;

[0025] Flexible membrane 30, hollow cylindrical membrane 31, circular membrane 32;

[0026] First pressure sensor 41, second pressure sensor 42, third pressure sensor 43, fourth pressure sensor 44, fifth pressure sensor 45. DETAILED DESCRIPTION

[0027] The present application is further described below in conjunction with the drawings and examples.

[0028] For the convenience of describing the direction, a space Cartesian coordinate system is established as shown in the figure. Figure 5 As shown in the figure, Figure 1 , 2As shown in Figures 3 and 4, this invention proposes a flexible three-dimensional force sensor structure for a medical surgical robot, comprising a rigid shell 10, a rigid crossbeam force transmission structure 20, a flexible membrane 30, and a pressure sensor. The rigid shell 10 consists of a hollow cylindrical structure 11 with four rectangular thin-walled structures 12 and a bottom cover 13. The four rectangular thin-walled structures 12 are symmetrically distributed around the inner wall of the hollow cylindrical structure 11. One end of each rectangular thin-walled structure 12 is connected to the hollow cylindrical structure 11, and the other end is sealed to the outer wall of the flexible membrane 30. The rigid crossbeam force transmission structure 20 consists of a crossbeam 21 and a cylinder 22. The crossbeam 21 consists of four rectangular beams arranged in a cross shape. The top of the center of the crossbeam 21 is connected to the cylinder 22, and the periphery of the crossbeam 21 is sealed to the inner wall of the flexible membrane 30. The cylinder 22 has a circular cross section, and the cylinder 22 is positioned near the top. Part of the sidewall is sealed to the circular film 32 in the flexible membrane 30; the flexible membrane 30 is composed of a hollow cylindrical film 31 and a circular film 32; the material used for the flexible membrane is silicone material formed by the natural curing of liquid silicone, which can bond metal and various materials such as plastic and rubber; the top of the hollow cylindrical film 31 is sealed to the circular film 32, the outer wall of the hollow cylindrical thin wall 31 and the bottom are sealed to the rigid shell 10, and the middle position of the inner wall of the hollow cylindrical film 31 is sealed to the cross beam 21 of the rigid cross beam force transmission structure 20; the circular hole in the middle position of the circular film 32 is sealed to the top cylindrical structure 22 of the rigid cross beam force transmission structure 20; the flexible membrane 30 and the rigid shell 10 form five cavities, namely one cavity inside the hollow cylindrical film, and four cavities separated by four rectangular thin-walled structures between the hollow cylindrical film and the rigid shell.

[0029] The sensor is fabricated as follows: First, a flexible membrane is prepared; then, the rigid crossbeam force transmission structure is sealed and connected to the flexible membrane with adhesive; five pressure sensors are placed in the cavities between each pair of the four rectangular thin-walled structures inside the rigid shell and in the cavity of the flexible membrane; finally, they are sealed and connected to the rigid shell with adhesive.

[0030] like Figure 5 As shown, the pressure sensor includes a first pressure sensor 41, a second pressure sensor 42, a third pressure sensor 43, a fourth pressure sensor 44, and a fifth pressure sensor 45. The first pressure sensor 41 is placed in the cavity in the positive X direction, the second pressure sensor 42 is placed in the cavity in the negative X direction, the third pressure sensor 43 is placed in the cavity in the positive Y direction, the fourth pressure sensor 44 is placed in the cavity in the negative Y direction, and the fifth pressure sensor 45 is placed in the central cavity.

[0031] The measurement process of the three-dimensional force sensor is as follows: when a force in a certain dimension acts on the top end cylinder 22 of the rigid cross beam force transmission structure 20, the cross beam 21 drives the flexible film 30 to deform, causing the corresponding cavity pressure to change, and the force value can be obtained through the pressure change. The pressure value difference of the two cavity pressure sensors 41 / 42 in the X direction is calculated to realize the X direction force measurement; the pressure value difference of the two cavity pressure sensors 43 / 44 in the Y direction is calculated to realize the Y direction force measurement; and the middle one cavity sensor 45 realizes the Z direction force measurement. The differential calculation of the pressure value effectively improves the measurement accuracy of the sensor.

Claims

1. A flexible three-dimensional force sensor for a medical surgical robot, characterized in that, The sensor comprises a rigid housing (10), a rigid crossbeam force transmission structure (20), a flexible membrane (30), and a pressure sensor; the rigid crossbeam force transmission structure (20) is located in the rigid housing (10); the flexible membrane (30) is located in the middle and upper part of the rigid housing (10), and the three parts of the rigid housing (10), the rigid crossbeam force transmission structure (20), and the flexible membrane (30) are coaxial; the pressure sensor is located at the bottom inside the rigid housing (10). The rigid shell (10) is composed of a hollow cylindrical structure (11) with four rectangular thin-walled structures (12) and a bottom cover (13); the four rectangular thin-walled structures (12) are symmetrically distributed around the inner wall of the hollow cylindrical structure (11); one end of the four rectangular thin-walled structures (12) is connected to the hollow cylindrical structure (11), and the other end is sealed to the outer wall of the hollow cylindrical film (31) in the flexible film (30); The rigid cross beam force transmission structure (20) is composed of a cross beam (21) and a cylinder (22); the cross beam (21) is composed of four rectangular beams arranged in a cross shape, the top center of the cross beam (21) is connected to one end of the cylinder (22), and the outer periphery of the cross beam (21) is sealed to the inner wall of the hollow cylindrical film (31) of the flexible membrane (30); the side wall of the upper part of the cylinder (22) is sealed to the circular film (32) in the flexible membrane (30); The flexible membrane (30) is composed of a hollow cylindrical membrane (31) and a circular membrane (32); the top end of the hollow cylindrical membrane (31) is sealed to the circular membrane (32), the outer wall and bottom end of the hollow cylindrical membrane (31) are sealed to the rigid shell (10), and the inner wall of the hollow cylindrical membrane (31) is sealed to the cross beam (21) of the rigid cross beam force transmission structure (20); five cavities are formed between the flexible membrane (30) and the rigid shell (10), namely one cavity inside the hollow cylindrical membrane (31), and four cavities between the hollow cylindrical membrane (31) and the rigid shell (10) separated by four rectangular thin-walled structures (12); The pressure sensors include a first pressure sensor (41), a second pressure sensor (42), a third pressure sensor (43), a fourth pressure sensor (44), and a fifth pressure sensor (45); the five pressure sensors are respectively located on the bottom cover (13) inside the rigid outer shell (10) of the five cavities.

2. The flexible three-dimensional force sensor for a medical surgical robot according to claim 1, characterized in that, The flexible membrane (30) is made of silicone material formed by the natural curing of liquid silicone, which can bond metals and various materials such as plastics and rubber.

3. The flexible three-dimensional force sensor for a medical surgical robot according to claim 1, characterized in that, The sensor is prepared as follows: first, a flexible membrane (30) is prepared; then, the rigid cross beam force transmission structure (20) and the flexible membrane (30) are sealed together with glue; five pressure sensors are placed in the cavities between the four rectangular thin-walled structures inside the rigid shell and in the cavity of the flexible membrane; finally, they are sealed together with the rigid shell with glue.

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