Six-Degree-of-Freedom Pneumatic Variable Stiffness CT-MRI Needle Insertion Robot

Abstract

The present invention discloses a six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness. The device includes a planar positioning module, a pneumatic attitude adjustment module, and a needle insertion module. The planar positioning module drives and locks the sub-slider to move within the moving mother-slider through pneumatic muscles to complete the locking and unlocking of the movement of the moving mother-slider; the pneumatic attitude adjustment module restricts the rotational degrees of freedom of the puncture needle on the ball joint in the state of inflating and deflating the airbag inside; the needle insertion module drives the steering gear through a long gear column to realize the control of the rotation angle of the puncture needle around the needle axis, and at the same time drives the needle insertion slider to move linearly along the screw through the rotation of the screw to realize the degrees of freedom of the needle insertion of the puncture needle. The structure of the present invention is compact, the control is simple, the processing materials are all non-metallic materials, it is compatible with CT-MRI, uses pneumatic to fix the attitude of the puncture needle, and uses a ceramic motor, a wire drive mechanism or manual drive to realize quantitative needle insertion.

Description

Technical Field

[0001] The present invention belongs to a puncture robot in the field of medical device manufacturing and application, and particularly relates to a six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness. Background Art

[0002] Clinically, if a lesion is detected in the lung through CT examination, but it is not certain whether it is caused by infection, non-lesion infection, or tumor, especially when malignant tumor cannot be excluded, lung puncture biopsy is required to clarify the nature of the lesion. Lung puncture is also to puncture into the lesion under the positioning of CT to take some tissues for routine examination. However, CT-guided puncture also has disadvantages: for example, due to non-real-time imaging, respiratory movement will cause errors in accurate positioning, and patients must be trained to master the respiratory phase. When the puncture needle needs to form a certain angle with the cross-section, the puncture technique is somewhat difficult, so the pose of the puncture needle needs to be adjusted continuously through CT images. However, the generation of CT images takes a certain amount of time, and the observation of CT images requires leaving the operating table. Therefore, during the lung puncture operation, the pose of the puncture needle needs to be adjusted continuously according to CT images before the puncture process. After initially determining the pose, the doctor pastes positioning paper at a suitable place to initially determine the position of the puncture point. Therefore, the operating doctor needs to continuously adjust the puncture needle and then fix the puncture needle. After completing the initial positioning, the doctor needs to leave the operating room and perform another CT scan on the patient to determine the needle insertion direction and angle and finally determine the insertion point. After determining the needle insertion, after the puncture needle enters the predetermined depth, another CT scan is required to determine the position of the needle tip; if the needle tip does not reach the lesion, adjustment is required according to the scan results, and this is repeated until the insertion is finally completed. Nowadays, in most cases, medical staff fix the puncture needle that has been inserted halfway into the patient through a puncture positioning needle. However, due to the breathing of the patient, the puncture needle will move along with it, and the puncture needle is extremely likely to shift or even fall off during the operation. Finally, problems such as surgical failure, inaccurate positioning, and excessive resection of lung tissue occur. The current solution of medical staff is to directly use tape or gauze winding fixation methods, and some use a gantry support on the operating table to fix the puncture needle. However, due to the breathing of the patient, the effect is often very poor. So it is very difficult to truly fix the puncture needle. And because of health reasons of medical staff, they cannot be exposed to radiation for a long time, and there can be no interference during the CT scan, so a medical staff cannot be arranged to manually fix it either. Therefore, there is an urgent need to develop a small puncture needle fixation device that can be attached to the patient, and this fixation device needs to achieve multi-degree-of-freedom movement to facilitate the doctor to control the movement trajectory of the insertion angle of the puncture needle and fix the puncture needle during the insertion process.

[0003] In practical applications, since this fixing device is used in liver puncture surgery, the device needs to be able to move within a 100mm * 100mm plane to ensure that the puncture needle can penetrate any position. At the same time, due to the uncertainty of the puncture position, it is often necessary to control not only the planar position of the puncture needle but also the spatial attitude of the puncture needle, that is, the penetration angle. Therefore, this fixing device also needs to control the swing angle of the puncture needle. However, too many degrees of freedom control means a more complex transmission mechanism. At the same time, this fixing device must be attached to the patient's chest, so the device needs to be compact and small. Therefore, under the condition of ensuring normal use, the device is currently designed to be able to control four degrees of freedom of the puncture needle to achieve movement along the horizontal plane, rotation in the vertical plane, and rotation in the horizontal plane. Finally, during the actual puncture process, the puncture depth and puncture rotation angle of the puncture needle also affect the hitting accuracy. Therefore, on the basis of the four-degree-of-freedom fixation, a module for quantitative rotation and puncture depth control of the puncture needle is additionally added.

[0004] Content of the invention patent

[0005] In order to achieve the functions required in the background technology, the present invention provides a pneumatic variable stiffness six-degree-of-freedom CT-MRI needle puncture robot. It can provide six degrees of freedom to assist in fixing the puncture needle, so as to assist doctors in accurately fixing the biopsy needle puncture in the CT-MRI working environment, improve the doctor's control ability of the puncture needle during the operation, and at the same time ensure that the puncture robot is not affected by the patient's respiratory movement during the puncture process.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention mainly consists of a two-degree-of-freedom planar positioning module, a two-degree-of-freedom attitude fixing module, and a two-degree-of-freedom rotating needle insertion module; the two-degree-of-freedom attitude fixing module is installed on the two-degree-of-freedom planar positioning module, the two-degree-of-freedom rotating needle insertion module is installed on the two-degree-of-freedom attitude fixing module, and the biopsy needle is installed on the two-degree-of-freedom rotating needle insertion module.

[0008] The described two-degree-of-freedom planar positioning module includes a base, a planar positioning mechanism, and an attitude fixing mechanism; the two bases are placed parallel to each other at intervals, and a transfer piece is installed at each end of each base. A planar positioning mechanism is installed between the two ends of the two bases. Each planar positioning mechanism includes a carbon fiber tube, a locking bar, and a female slider; the two carbon fiber tubes pass through the female slider in parallel and at intervals and are fixedly connected to one end of the two bases through the transfer piece. The two locking bars also pass through the female slider in parallel and at intervals and are fixedly connected to one end of the two bases through the transfer piece. The two locking bars are located below the carbon fiber tubes and are placed parallel to and at intervals from the two carbon fiber tubes; an attitude fixing mechanism with basically the same structure as the planar positioning mechanism is also installed between the female sliders of the two planar positioning mechanisms. The female slider in the attitude fixing mechanism serves as the needle base female slider, and the carbon fiber tube and the locking bar in the attitude fixing mechanism are both fixedly connected to the two female sliders.

[0009] Both the female slider and the needle base female slider are hollow inside. Inside each of them, an air duct, a pneumatic muscle, a pulling rope, and two sub-locking sliders are horizontally arranged perpendicular to the sliding direction of the female slider and the needle base female slider respectively; the pneumatic muscle and the pulling rope are located between the two sub-locking sliders, and the air duct is installed on the pneumatic muscle; after the air duct inflates the pneumatic muscle, the pneumatic muscle begins to expand and push the sub-locking sliders to move inside the female slider or the needle base female slider until the serrated surface provided on the outside of the locking slider coincides with the serrated surface provided on the inside of the locking bar, forming a structural limit. The female slider or the needle base female slider is fixed at the current position, and at the same time, the pulling rope is tightened; when the pneumatic muscle does not work, the pulling rope pulls the two sub-locking sliders inwardly, and the serrated surface on the outside of the sub-locking slider is separated from the serrated surface on the inside of the locking bar, and the structural limit of the female slider or the needle base female slider is released.

[0010] The two female sliders and one needle base female slider use the carbon fiber tube as a guide rail and slide freely along the carbon fiber tube; the female sliders and the needle base female slider are in sliding contact with the upper and lower surfaces of the locking bar to slide freely along the locking bar and are not in contact with the serrated surface on the inside of the locking bar.

[0011] The attitude fixing mechanism also includes a ball joint, which is sleeved at the center position inside the needle base female slider and is movably connected to the needle base female slider;

[0012] The two-degree-of-freedom attitude fixing module includes a locking airbag base, a locking airbag, a puncture needle sleeve, and airbag locking particles; the puncture needle sleeve sequentially passes through the center through-holes of the locking airbag, the locking airbag base, and the needle base female slider from top to bottom and is fixedly installed on a ball joint installed inside the needle base female slider; the locking airbag base is fixedly installed on the upper part of the needle base female slider, the locking airbag is fixedly installed on the airbag base, an air inlet pipe is arranged on the side of the locking airbag, and a number of airbag locking particles are arranged inside the locking airbag, and the locking airbag is connected to an external vacuum pump through the air inlet pipe.

[0013] The two-degree-of-freedom rotating needle insertion module includes a lower fixing seat of the needle insertion module, a carbon fiber tube B, a needle insertion slider, a boss gear, a screw, a gear limiting member, a biopsy needle, an upper limiting seat of the needle insertion module, a coupling, and a long gear column; the upper limiting seat of the needle insertion module is located directly above the lower fixing seat of the needle insertion module, and the lower fixing seat of the needle insertion module and the upper limiting seat of the needle insertion module are connected by a vertical carbon fiber tube B, and the screw and the long gear column are vertically arranged between the lower fixing seat of the needle insertion module and the upper limiting seat of the needle insertion module parallel to the carbon fiber tube B. The upper ends of the screw and the long gear column pass through the upper limiting seat of the needle insertion module and are respectively connected to an external driving source through their respective couplings;

[0014] An needle insertion slider is arranged between the upper limiting seat of the needle insertion module and the lower fixing seat of the needle insertion module. A boss gear is hinged on the needle insertion slider. The needle insertion slider is provided with a center through-hole, and the biopsy needle sequentially passes through the center through-hole of the needle insertion slider from bottom to top and is fixedly sleeved on the through-hole where the central axis of the boss gear is located;

[0015] The two-degree-of-freedom rotating needle insertion module further includes a gear limiting member. A gear limiting member for protecting the boss gear is arranged on the needle insertion slider, and the biopsy needle simultaneously passes through the through-hole opened on the gear limiting member.

[0016] The needle insertion slider forms a rotating pair with the screw through the internal thread provided on the side. The rotation of the screw drives the needle insertion slider to perform a linear motion along the axis direction of the screw. The biopsy needle sequentially passes through the through-holes of the gear limiting member, the boss gear, and the needle insertion slider from top to bottom and is fixedly sleeved on the central axis of the boss gear. The boss gear is meshed with the long gear column to form a gear pair. The long gear column drives the boss gear to perform a circular rotation through the gear pair, thereby driving the biopsy needle to rotate around its own axis. The biopsy needle passes through the needle insertion module bracket and then continues to pass through the puncture needle sleeve and finally reaches the target human body; the lower fixing seat of the needle insertion module in the needle insertion module bracket is connected downward to the locking airbag.

[0017] The locking airbag uses negative pressure contraction to restrict the fluidity of the airbag locking particles inside the locking airbag and controls the puncture needle sleeve to be fixed in any attitude.

[0018] The described long gear column cooperates with the boss gear to control the biopsy needle for angular quantitative rotation; the described screw cooperates with the needle advancing slider to control the needle advancing length of the biopsy needle to achieve quantitative needle advancement.

[0019] The overall mechanism is made of non-metallic materials.

[0020] The two-degree-of-freedom rotary needle insertion module is externally connected to a ceramic machine and a wire drive mechanism through a coupling to achieve machine drive, or directly manually driven to achieve human-machine switching.

[0021] The described ball hinge is movably connected inside the needle seat female slider to form a rotating pair with the needle seat female slider.

[0022] The beneficial effects of the present invention are:

[0023] All components of the present invention are made of non-metallic materials, ensuring that there are no metal densifications in the CT section and inside the MRI during the needle puncture operation, and it can be compatible with CT-MRI equipment to achieve CT-MRI imaging.

[0024] The present invention adopts a modular design concept. The three sub-modules are not dependent on each other and can be used independently.

[0025] Based on the principle that the fluidity of the particulate matter inside the airbag decreases under the pneumatic negative pressure state, the present invention designs and manufactures a variable stiffness puncture needle barrel fixing module, that is, a two-degree-of-freedom attitude fixing module, which can fix the puncture needle in any attitude, with a simple design and a compact structure.

[0026] The present invention provides a four-degree-of-freedom passive pose fixing function and a two-degree-of-freedom active needle insertion function for the puncture needle, which can provide arbitrary pose fixing of the puncture needle and provide functions of quantitative needle insertion and rotation operation. Description of the Drawings

[0027] Figure 1 is the overall assembly drawing of the present invention;

[0028] Figure 2 is the two-degree-of-freedom planar positioning module of the present invention;

[0029] Figure 3 is the two-degree-of-freedom pneumatic attitude adjustment module of the present invention;

[0030] Figure 4 is the two-degree-of-freedom needle insertion module of the present invention;

[0031] Figure 5 is the part drawing of part 4;

[0032] Figure 6 is the part drawing of part 5;

[0033] Figure 7 Part 4 locking bar part drawing.

[0034] 1 - Base, 2 - Adapter, 3 - Carbon fiber tube A, 4 - Locking bar, 5 - Female slider, 6 - Air duct, 7 - Needle seat female slider, 8 - Locking airbag base, 9 - Lower fixing seat of needle insertion module, 10 - Locking airbag, 11 - Carbon fiber tube B, 12 - Needle insertion slider, 13 - Boss gear, 14 - Screw, 15 - Gear position limiter, 16 - Biopsy needle, 17 - Upper fixing seat of needle insertion module, 18 - Coupling, 19 - Puncture needle sleeve, 20 - Ball hinge, 21 - Pneumatic muscle, 22 - Tension rope, 23 - Sub - locking slider, 24 - Airbag locking particle, 25 - Long gear column, 26 - Air inlet pipe. Detailed implementation mode

[0035] As Figure 1 shown in the overall assembly drawing, through modular design, the six - degree - of - freedom robot is split into three independent working modules, mainly composed of a two - degree - of - freedom planar positioning module, a two - degree - of - freedom attitude fixing module, and a two - degree - of - freedom rotary needle insertion module; the two - degree - of - freedom attitude fixing module is installed on the two - degree - of - freedom planar positioning module, the two - degree - of - freedom rotary needle insertion module is installed on the two - degree - of - freedom attitude fixing module, and the biopsy needle 16 is installed on the two - degree - of - freedom rotary needle insertion module. The two - degree - of - freedom planar positioning module drives the two - degree - of - freedom attitude fixing module to move horizontally, the two - degree - of - freedom attitude fixing module drives the two - degree - of - freedom rotary needle insertion module to tilt along the needle insertion direction, and the two - degree - of - freedom rotary needle insertion module drives the biopsy needle 16 to move up and down and rotate self - rotatably.

[0036] Specifically, the two - degree - of - freedom planar positioning module includes a base 1, a planar positioning mechanism, and an attitude fixing mechanism; two bases 1 are placed in parallel and relatively spaced apart, and a connector 2 is installed at each end of each base 1. A planar positioning mechanism is installed between the two ends of the two bases 1. Each planar positioning mechanism includes a carbon fiber tube 3, a locking bar 4, and a female slider 5; two carbon fiber tubes 3 pass through the female slider 5 in parallel and relatively spaced apart and are fixedly connected to one end of the two bases 1 through the connector 2. Two locking bars 4 also pass through the female slider 5 in parallel and relatively spaced apart and are fixedly connected to one end of the two bases 1 through the connector 2. The two locking bars 4 are placed below the carbon fiber tubes 3 and are parallel and relatively spaced apart from the two carbon fiber tubes 3 respectively; an attitude fixing mechanism with basically the same structure as the planar positioning mechanism is also installed between the female sliders 5 of the two planar positioning mechanisms. The female slider 5 in the attitude fixing mechanism serves as the needle seat female slider 7, and the carbon fiber tube 3 and the locking bar 4 in the attitude fixing mechanism are fixedly connected to the two female sliders 5. Among them, the base 1 provides support and fixation for the carbon fiber tube 3 and the locking bar 4 through the connector 2.

[0037] As Figure 2 and Figure 5The shown two-degree-of-freedom planar positioning module and the parts of the needle base female slider 7. Both the female slider 5 and the needle base female slider 7 are hollow inside. Inside them, respectively, a gas pipe 6, a pneumatic muscle 21, a tension rope 22, and two sub-locking sliders 23 are horizontally arranged perpendicular to the sliding directions of the female slider 5 and the needle base female slider 7; the pneumatic muscle 21 and the tension rope 22 are located between the two sub-locking sliders 23, and the gas pipe 6 is installed on the pneumatic muscle 21; after the gas pipe 6 inflates the pneumatic muscle 21, the pneumatic muscle 21 starts to expand and push the sub-locking sliders 23 to move inside the female slider 5 or the needle base female slider 7 until the serrated surface provided on the outside of the locking slider 23 coincides with the serrated surface provided on the inside of the locking bar 4, forming a structural limit. The female slider 5 or the needle base female slider 7 is fixed at the current position, and at the same time, the tension rope 22 is tightened; when the pneumatic muscle 21 does not work, the tension rope 22 pulls the two sub-locking sliders 23 inwardly, and the serrated surface on the outside of the sub-locking slider 23 is separated from the serrated surface on the inside of the locking bar 4, and the structural limit of the female slider 5 or the needle base female slider 7 is released. The pneumatic muscle 21 drives the sub-locking slider 23 to cooperate with the serrated surface to complete the switching of the sliding / locking states of the female slider 5 and the needle base female slider 7 on the guide rail, thereby completing the planar positioning.

[0038] Both two female sliders 5 and one needle base female slider 7 use the carbon fiber tube 3 as the guide rail and slide freely along the carbon fiber tube 3; both the female slider 5 and the needle base female slider 7 slide in contact with the upper and lower surfaces of the locking bar 4 to slide freely along the locking bar 4 and do not contact the serrated surface on the inside of the locking bar 4. The part drawing of the locking bar 4 is as Figure 7 shown. In addition, the attitude fixing mechanism further includes a ball joint 20. The ball joint 20 is sleeved at the central position inside the needle base female slider 7 and is movably connected to the needle base female slider 7.

[0039] As Figure 3The shown two-degree-of-freedom pneumatic attitude adjustment module. The two-degree-of-freedom attitude fixing module includes a locking airbag base 8, a locking airbag 10, a puncture needle sleeve 19, and airbag locking particles 24. The puncture needle sleeve 19 sequentially passes through the center through holes of the locking airbag 10, the locking airbag base 8, and the needle seat female slider 7 from top to bottom and is fixedly installed on the ball joint 20 installed inside the needle seat female slider 7. The locking airbag base 8 is fixedly installed on the upper part of the needle seat female slider 7, the locking airbag 10 is fixedly installed on the airbag base 8. The needle seat female slider 7 provides an installation fulcrum for the ball joint 20 and the locking airbag base 8. An air inlet pipe 26 is provided on the side of the locking airbag 10, and a number of airbag locking particles 24 are provided inside the locking airbag 10. The airbag locking particles 24 are circular small balls that can flow freely inside the airbag. The locking airbag 10 is connected to an external vacuum pump through the air inlet pipe 26. When the inside of the locking airbag 10 is evacuated, the locking airbag 10 shrinks, squeezing the airbag locking particles 24. After the fluidity of the airbag locking particles 24 disappears, a fixed body is formed with the locking airbag 10 in the current posture. The puncture needle sleeve 19 on the ball joint 20 is locked in the current posture by the fixed body, thereby restricting the two degrees of freedom corresponding to the ball joint 20, that is, the degrees of freedom of rotation around the x-axis and around the y-axis.

[0040] As Figure 4 The shown two-degree-of-freedom needle insertion module. The two-degree-of-freedom rotary needle insertion module includes a lower fixed seat 9 of the needle insertion module, a carbon fiber tube B11, a needle insertion slider 12, a boss gear 13, a screw 14, a gear limiting member 15, a biopsy needle 16, an upper limit seat 17 of the needle insertion module, a coupling 18, and a long gear column 25. The upper limit seat 17 of the needle insertion module is located directly above the lower fixed seat 9 of the needle insertion module. Among them, the lower fixed seat 9 of the needle insertion module and the upper limit seat 17 of the needle insertion module are connected by a vertical carbon fiber tube B11. The screw 14 and the long gear column 25 are vertically arranged parallel to the carbon fiber tube B11 between the lower fixed seat 9 of the needle insertion module and the upper limit seat 17 of the needle insertion module. The upper ends of the screw 14 and the long gear column 25 pass through the upper limit seat 17 of the needle insertion module and are respectively connected to an external drive source through their respective couplings 18.

[0041] An needle insertion slider 12 is provided between the upper limit seat 17 of the needle insertion module and the lower fixed seat 9 of the needle insertion module. A boss gear 13 is hinged on the needle insertion slider 12. The needle insertion slider 12 is provided with a center through hole. The biopsy needle 16 sequentially passes through the center through hole of the needle insertion slider 12 from bottom to top and is fixedly sleeved on the through hole where the central axis of the boss gear 13 is located.

[0042] Among them, the two-degree-of-freedom rotary needle insertion module further includes a gear limiting member 15. A gear limiting member 15 for protecting the boss gear 13 is provided on the needle insertion slider 12. The biopsy needle 16 also passes through the through hole opened on the gear limiting member 15.

[0043] The needle-inserting slider 12 forms a rotary pair with the screw rod 14 through the internal thread provided on the side. The rotation of the screw rod 14 drives the needle-inserting slider 12 to perform a linear motion along the axis of the screw rod 14, that is, to move along the z-axis. The biopsy needle 16 sequentially passes through the central through holes of the gear limiting member 15, the boss gear 13, and the needle-inserting slider 12 from top to bottom and is fixedly sleeved on the central axis of the boss gear 13. The boss gear 13 is meshed and connected with the long gear column 25 to form a gear pair. The long gear column 25 drives the boss gear 13 to perform a circumferential rotation through the gear pair, and then drives the biopsy needle 16 to rotate around its own axis, that is, to rotate along the z-axis. The part drawing of the long gear column 25 is as Figure 6 shown. The biopsy needle 16 passes through the needle-inserting module bracket and then continues to pass through the puncture needle sleeve 19, and finally reaches the target human body; the lower fixed seat 9 of the needle-inserting module in the needle-inserting module bracket is connected downward to the locking airbag 10. The gear limiting member 15 is used to maintain the relative position between the boss gear 13 and the needle-inserting slider 12.

[0044] In a specific implementation, the locking airbag 10 uses negative pressure contraction to limit the fluidity of the airbag locking particles 24 inside the locking airbag 10 to achieve variable stiffness transformation, and controls the puncture needle sleeve 19 to be fixed in any posture.

[0045] Among them, the long gear column 25 cooperates with the boss gear 13 to control the biopsy needle 16 to perform angular quantitative rotation; the screw rod 14 cooperates with the needle-inserting slider 12 to control the needle-inserting length of the biopsy needle 16 to achieve quantitative needle insertion. The ball hinge 20 is movably connected with the needle seat female slider 7 inside the needle seat female slider 7 to form a rotary pair.

[0046] Among them, the two-degree-of-freedom rotary needle-inserting module is externally connected to a ceramic machine and a wire drive mechanism through a coupling to achieve machine drive, or directly manually driven to achieve human-machine switching. And the overall mechanism is made of non-metallic materials and can be compatible with CT-MRI detection equipment.

Claims

1. A six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness, characterized in that; It mainly consists of a two-degree-of-freedom planar positioning module, a two-degree-of-freedom attitude fixing module, and a two-degree-of-freedom rotating needle insertion module; the two-degree-of-freedom attitude fixing module is installed on the two-degree-of-freedom planar positioning module, the two-degree-of-freedom rotating needle insertion module is installed on the two-degree-of-freedom attitude fixing module, and the biopsy needle (16) is installed on the two-degree-of-freedom rotating needle insertion module; The two-degree-of-freedom planar positioning module mentioned above includes a base (1), a planar positioning mechanism, and an attitude fixing mechanism; the two bases (1) are placed parallel to each other at intervals, and a transfer member (2) is installed at each end of each base (1). A planar positioning mechanism is installed between the two ends of the two bases (1). Each planar positioning mechanism includes a carbon fiber tube (3), a locking bar (4), and a female slider (5); the two carbon fiber tubes (3) pass through the female slider (5) in parallel and at intervals and are fixedly connected to one end of the two bases (1) through the transfer member (2). The two locking bars (4) also pass through the female slider (5) in parallel and at intervals and are fixedly connected to one end of the two bases (1) through the transfer member (2). The two locking bars (4) are located below the carbon fiber tubes (3) and are placed parallel to and at intervals from the two carbon fiber tubes (3); an attitude fixing mechanism with basically the same structure as the planar positioning mechanism is also installed between the female sliders (5) of the two planar positioning mechanisms. The female slider (5) in the attitude fixing mechanism serves as the needle seat female slider (7), and the carbon fiber tube (3) and the locking bar (4) in the attitude fixing mechanism are fixedly connected to the two female sliders (5); Both the female slider (5) and the needle seat female slider (7) are hollow inside. Inside them, a gas guide tube (6), a pneumatic muscle (21), a pull rope (22), and two sub-locking sliders (23) are horizontally arranged perpendicular to the sliding directions of the female slider (5) and the needle seat female slider (7) respectively; the pneumatic muscle (21) and the pull rope (22) are located between the two sub-locking sliders (23), and the gas guide tube (6) is installed on the pneumatic muscle (21); after the gas guide tube (6) inflates the pneumatic muscle (21), the pneumatic muscle (21) starts to expand and push the sub-locking sliders (23) to move inside the female slider (5) or the needle seat female slider (7) until the serrated surface provided on the outside of the locking slider (23) coincides with the serrated surface provided on the inside of the locking bar (4) to form a structural limit. The female slider (5) or the needle seat female slider (7) is fixed at the current position, and at the same time, the pull rope (22) is tightened; when the pneumatic muscle (21) does not work, the pull rope (22) pulls the two sub-locking sliders (23) inwardly, and the serrated surface on the outside of the sub-locking slider (23) is separated from the serrated surface on the inside of the locking bar (4), and the structural limit of the female slider (5) or the needle seat female slider (7) is released; The attitude fixing mechanism also includes a ball joint (20). The ball joint (20) is sleeved at the central position inside the needle seat female slider (7) and is movably connected to the needle seat female slider (7); The two-degree-of-freedom attitude fixing module includes a locking airbag base (8), a locking airbag (10), a puncture needle sleeve (19), and airbag locking particles (24); the puncture needle sleeve (19) sequentially passes through the center through holes of the locking airbag (10), the locking airbag base (8), and the needle base female slider (7) from top to bottom and is fixedly installed on the ball hinge (20) installed inside the needle base female slider (7); the locking airbag base (8) is fixedly installed on the upper part of the needle base female slider (7), the locking airbag (10) is fixedly installed on the airbag base (8), an air inlet pipe (26) is arranged on the side of the locking airbag (10), and a number of airbag locking particles (24) are arranged inside the locking airbag (10), and the locking airbag (10) is connected to an external vacuum pump through the air inlet pipe (26).

2. The pneumatic variable stiffness six-degree-of-freedom CT-MRI needle puncture robot according to claim 1, characterized in that: The two female sliders (5) and one needle base female slider (7) use a carbon fiber tube (3) as a guide rail and slide freely along the carbon fiber tube (3); the female sliders (5) and the needle base female slider (7) are in sliding contact with the upper and lower surfaces of the locking bar (4) to slide freely along the locking bar (4) and are not in contact with the inner serrated surface of the locking bar (4).

3. A pneumatic variable stiffness six-degree-of-freedom CT-MRI needle puncture robot according to claim 1, characterized in that: The two-degree-of-freedom rotary needle insertion module includes a needle insertion module lower fixing seat (9), a carbon fiber tube B (11), a needle insertion slider (12), a boss gear (13), a screw (14), a gear limiting member (15), a biopsy needle (16), a needle insertion module upper limiting seat (17), a coupling (18), and a long gear column (25); the needle insertion module upper limiting seat (17) is located directly above the needle insertion module lower fixing seat (9), and the needle insertion module lower fixing seat (9) and the needle insertion module upper limiting seat (17) are connected by a vertical carbon fiber tube B (11), and the screw (14) and the long gear column (25) are vertically arranged between the needle insertion module lower fixing seat (9) and the needle insertion module upper limiting seat (17) parallel to the carbon fiber tube B (11), and the upper ends of the screw (14) and the long gear column (25) pass through the needle insertion module upper limiting seat (17) and are respectively connected to an external drive source through their respective couplings (18); An needle insertion slider (12) is arranged between the needle insertion module upper limiting seat (17) and the needle insertion module lower fixing seat (9), a boss gear (13) is hinged on the needle insertion slider (12), the needle insertion slider (12) is provided with a center through hole, and the biopsy needle (16) sequentially passes through the center through hole of the needle insertion slider (12) from bottom to top and is fixedly sleeved on the through hole where the central axis of the boss gear (13) is located; The two-degree-of-freedom rotary needle insertion module further includes a gear limiting member (15), a gear limiting member (15) for protecting the boss gear (13) is arranged on the needle insertion slider (12), and the biopsy needle (16) also passes through the through hole opened on the gear limiting member (15) movably; The described needle - advancing slider (12) forms a rotary pair with the screw rod (14) through the internal thread provided on the side. The rotation of the screw rod (14) drives the needle - advancing slider (12) to perform a linear motion along the axis direction of the screw rod (14). The biopsy needle (16) sequentially passes through the center through - holes of the gear limit member (15), the boss gear (13), and the needle - advancing slider (12) from top to bottom and is fixedly sleeved on the central axis of the boss gear (13). The boss gear (13) is meshed with the long gear column (25) to form a gear pair. The long gear column (25) drives the boss gear (13) to perform a circular rotation through the gear pair, thereby driving the biopsy needle (16) to rotate around its own axis. The biopsy needle (16) passes through the needle - advancing module bracket and then continues to pass through the puncture needle sleeve (19) and finally reaches the target human body. The needle - advancing module lower fixed seat (9) in the needle - advancing module bracket is connected downward to the locking airbag (10).

4. The six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness according to claim 1, characterized in that: The locking airbag (10) uses negative pressure contraction to restrict the fluidity of the airbag locking particles (24) inside the locking airbag (10) and controls the puncture needle sleeve (19) to be fixed in any posture.

5. The six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness according to claim 3, wherein: The long gear column (25) cooperates with the boss gear (13) to control the biopsy needle (16) to perform a quantitative angular rotation. The screw rod (14) cooperates with the needle - advancing slider (12) to control the needle - advancing length of the biopsy needle (16) to achieve quantitative needle advancement.

6. The six-degree-of-freedom CT-MRI needle puncture robot with pneumatic variable stiffness according to claim 1, characterized in that: The overall mechanism is made of non - metallic materials.

7. A pneumatic variable stiffness six-degree-of-freedom CT-MRI needle puncture robot according to claim 1, characterized in that: [[ID=]4]The two - degree - of - freedom rotary needle - advancing module is externally connected to a ceramic machine and a wire - driven mechanism through a coupling to achieve machine drive, or is directly manually driven to achieve human - machine switching.

8. A pneumatic variable stiffness six-degree-of-freedom CT-MRI needle puncture robot according to claim 1, characterized in that: The described ball hinge (20) is movably connected inside the needle - seat female slider (7) to form a rotary pair with the needle - seat female slider (7).

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