A nuclear magnetic resonance compatible force sensing needle advancement device

Abstract

The application discloses a nuclear magnetic compatible force sensing needle insertion device, which is made of non-metallic material, and a support is fixedly connected with a base and a navigation device; a fixed rack is arranged in parallel with the support and is fixedly installed at both ends of the support; a pneumatic needle insertion cylinder body is sleeved with the outer circumferential side of the fixed rack and is connected with a gas supply system, engagement of the pneumatic needle insertion cylinder body and the fixed rack is pneumatically controlled by using the gas supply system, so that movement of the pneumatic needle insertion cylinder body along the fixed rack is realized; an optical fiber of a force sensing sensor is fixedly connected with the inner wall of a circular tubular body; a rectangular groove is arranged on the side wall of the circular tubular body; each optical fiber forms a first FBG sensor located in the rectangular groove area and a second FBG sensor located outside the rectangular groove area; a puncture needle and one end of the circular tubular body are fixedly installed on the pneumatic needle insertion cylinder body. The needle insertion device realizes accurate control of puncture needle insertion based on the pneumatic needle insertion cylinder body, and realizes accurate control of the end force based on the FBG sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of puncture surgical devices, in particular to a nuclear magnetic resonance compatible force sensing needle insertion device. BACKGROUND

[0002] Currently, the operation mode of minimally invasive percutaneous puncture surgery mainly adopts the "blind puncture type" surgical method of "scanning positioning-puncturing-scanning confirmation", which leads to longer radiation exposure time for doctors and patients, insufficient puncture accuracy, and excessive dependence on doctors' experience, increasing the risk of complications. In order to improve the safety and accuracy of surgery, a more precise and controllable operation mode is urgently needed to reduce radiation exposure, improve puncture accuracy, and reduce the burden of doctors on the learning curve.

[0003] Precise force sensing and precise puncture control are essential background requirements for puncture surgical robots. During the puncture process, the robot must have the ability to detect and feedback the changes of different tissue resistances in real time, in order to avoid damaging sensitive tissues and ensure the accuracy of puncture depth. This requires the robot to be equipped with high-precision force sensors that can accurately measure small changes in force and feedback to the control system. In addition, the robot also needs to have the ability to accurately control the movement of the puncture needle according to the force feedback and the preset path, including the control of movement direction, speed and depth. To meet these requirements, the combination of advanced control algorithms and high-precision motion control mechanisms is crucial, thereby improving the safety and success rate of surgery.

[0004] During the puncture surgery process, the robot often needs to operate in a CT (Computed Tomography) or MRI (Nuclear magnetic resonance) environment. In the CT environment, autonomous puncture needle insertion requires the robot to have as few metal structures as possible to reduce artifacts. In the nuclear magnetic environment, autonomous puncture needle insertion requires the puncture device to be made of non-magnetic materials to avoid interfering with the magnetic field and radio frequency signals of the MRI equipment, thereby ensuring the imaging quality.

[0005] The electronic components of the robot must be able to work normally in a strong magnetic field and radio frequency environment, preventing the environment from interfering with the robot's control system. These requirements require the robot system to use special shielding techniques and optical fiber communication instead of traditional cable connections.

[0006] In summary, precise puncture position control, precise force sensing, low artifact, and nuclear magnetic compatible autonomous puncture needle insertion device have become important factors restricting the further development of puncture robots in the clinical market. SUMMARY

[0007] The application provides a nuclear magnetic compatible force sensing needle insertion device, which realizes precise control of puncture needle insertion based on a pneumatic needle insertion cylinder and realizes precise control of end force based on an FBG (fiber Bragg grating) sensor.

[0008] The application adopts the following specific technical solutions:

[0009] The nuclear magnetic compatible force sensing needle insertion device is made of non-metallic materials and comprises a puncture needle, a locking device, a force sensing sensor, a pneumatic needle insertion cylinder, a navigation device, a support, a fixed rack and a base.

[0010] One end of the support is fixedly connected with the base, and the other end is fixedly connected with the navigation device.

[0011] The base is provided with a guide hole for guiding the puncture needle.

[0012] The fixed rack is arranged in parallel with the support and is fixedly installed at both ends of the support.

[0013] The pneumatic needle insertion cylinder is sleeved on the outer circumferential side of the fixed rack and is connected with a gas supply system, the engagement of the pneumatic needle insertion cylinder and the fixed rack is pneumatically controlled by the gas supply system, so that the movement of the pneumatic needle insertion cylinder along the fixed rack is realized.

[0014] The force sensing sensor comprises a circular tubular body and three or four optical fibers uniformly distributed along the circumference of the circular tubular body; the optical fibers extend along the axial direction of the circular tubular body and are fixedly connected to the inner wall of the circular tubular body; a plurality of rectangular grooves corresponding to each optical fiber are arranged on the side wall of the circular tubular body; each optical fiber forms a first FBG sensor located in the rectangular groove area and a second FBG sensor located outside the rectangular groove area; the first FBG sensor of the optical fiber is used to realize three-dimensional force sensing of the end, and the second FBG sensor of the optical fiber is used to realize temperature compensation of the sensor.

[0015] The puncture needle and one end of the circular tubular body are fixedly installed on the side of the pneumatic needle insertion cylinder away from the support and move along the fixed rack with the pneumatic needle insertion cylinder.

[0016] The puncture needle is arranged in parallel with the fixed rack and is fixedly installed on the other end of the circular tubular body through the locking device, and the middle part passes through the guide hole.

[0017] The navigation device is used to realize spatial positioning of the puncture needle.

[0018] Further, one side of the fixed rack is provided with a wide sliding platform, the other side is provided with a thin sliding platform, and a plurality of teeth are arranged in the middle of the two side surfaces;

[0019] The pneumatic needle insertion cylinder body comprises a cylinder upper part, a cylinder middle part and a cylinder lower part which are sequentially fixedly connected; the cylinder upper part is provided with an upper sliding groove on one side surface facing the cylinder middle part; four air pipe joints are symmetrically arranged on the two sides of the cylinder middle part, and the air pipe joints are connected with the air supply system through a hose; the cylinder middle part is internally provided with a middle sliding groove, and two pistons are embedded in the middle sliding groove; air chambers corresponding to the air pipe joints are formed between the two sides of the pistons and the inner surface of the cylinder middle part; the middle sliding groove is matched with the thin sliding platform, and the upper sliding groove is matched with the wide sliding platform, so that the pneumatic needle insertion cylinder body has only one sliding degree along the extension direction of the fixed rack;

[0020] The inner surface of the piston is provided with a plurality of teeth opposite to the teeth of the fixed rack; the opening and closing of the four air chambers are controlled by the air supply system, so as to realize the alternate meshing between the teeth of different pistons and the teeth of the fixed rack.

[0021] Further, a plurality of upper mounting holes are arranged on the circumference of the cylinder upper part; a plurality of middle mounting holes corresponding to the upper mounting holes are arranged on the circumference of the cylinder middle part; a plurality of lower mounting holes corresponding to the upper mounting holes are arranged on the circumference of the cylinder lower part; the cylinder upper part, the cylinder middle part and the cylinder lower part are fixedly connected by fasteners sequentially penetrating through the upper mounting holes, the middle mounting holes and the lower mounting holes, so as to ensure the airtightness of each air chamber.

[0022] Further, a top locking ring is arranged on the side surface of the cylinder upper part away from the cylinder middle part; a top puncture needle locking ring is fixedly connected to the top of the top locking ring, and a top puncture needle guide groove is arranged in the center of the top puncture needle locking ring; the top locking ring is sleeved on the outer circumferential side of the circular tubular body and fixedly connects the circular tubular body to the cylinder upper part;

[0023] The locking device comprises a bottom locking ring locked to the outer circumferential side of the circular tubular body and a bottom puncture needle locking ring fixedly connected to the bottom locking ring; a bottom puncture needle groove for clamping the puncture needle is arranged in the center of the bottom puncture needle locking ring;

[0024] The top of the puncture needle is guided through the top puncture needle guide groove, and the puncture needle is fixedly installed in the pneumatic needle insertion cylinder body through the bottom puncture needle locking ring.

[0025] Further, the top locking ring is internally provided with a top protruding column; the bottom locking ring is internally provided with a bottom protruding column;

[0026] One end of the circular tubular body is provided with a top groove, and the other end is provided with a bottom groove;

[0027] The top groove is matched with the top protruding column in shape, used for positioning between the top groove and the upper part of the cylinder body, and locked by the top locking ring;

[0028] The bottom groove is matched with the bottom protruding column in shape, used for positioning of the locking device, and locked by the bottom locking ring.

[0029] Further, the navigation device comprises a navigation base and three navigation indicating balls in triangular distribution;

[0030] One side of the navigation base is fixedly installed on the support, and the other side is fixedly installed with the navigation indicating balls;

[0031] A space coordinate system is established based on the spatial positions of the three navigation indicating balls, so as to obtain the spatial position of the puncture needle.

[0032] Further, the support is provided with opposite first positioning grooves at both ends of the side facing the fixed rack, and is provided with a quick release structure for quick disassembly and assembly with an external platform at the middle of the other side away from the fixed rack;

[0033] One end of the fixed rack is provided with an upper positioning table, and the other end is provided with a lower positioning table; the upper positioning table is inserted and matched with the first positioning groove at one end of the support, the lower positioning table is inserted and matched with the first positioning groove at the other end of the support, and the upper positioning table and the support are fixedly connected by a fastener.

[0034] Further, the support is provided with a first mounting hole and a second positioning groove at the end where the navigation base is installed;

[0035] The navigation base is provided with a second mounting hole corresponding to the position of the first mounting hole, and a positioning table corresponding to the position and shape of the second positioning groove;

[0036] The navigation base and the support are positioned by the insertion and matching of the positioning table and the second positioning groove, and are fixedly connected by the fastener installed in the corresponding first mounting hole and second mounting hole.

[0037] Further, the circular tubular body is provided with a plurality of glue injection holes;

[0038] The optical fiber is bonded in the circular tubular body by the glue injected through the glue injection hole.

[0039] Further, the base is provided with a mounting positioning part;

[0040] The base mounting table is connected with the mounting positioning part and locked, so as to realize the positioning connection of the base and the support.

[0041] The base mounting table is connected with the mounting positioning part and locked, so as to realize the positioning connection of the base and the support.

[0042] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0043] The nuclear magnetic compatible force sensing needle insertion device is made of non-metallic material, the force sensing sensor is realized based on an FBG (fiber Bragg grating) sensor, the driving of the puncture needle is realized through a pneumatic system, and the nuclear magnetic compatibility is achieved; the step length of the pneumatic needle insertion cylinder body is determined by the width of the fixed rack, and can be accurately controlled to 0.25 mm, so that the performance of the puncture robot reaches a new height in fine control, and additional protection is provided for the safety of patients; the robot can more reliably assist doctors to complete high-precision medical operations without interfering with electromagnetic sensitive equipment, and plays an important role in complex surgical procedures and precise treatment. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall structure of the force sensing needle insertion device of the present application;

[0045] Figure 2 It is a schematic diagram of the structure of the navigation device;

[0046] Figure 3 It is a schematic diagram of the structure of the support;

[0047] Figure 4 It is a schematic diagram of the structure of the fixed rack;

[0048] Figure 5 It is a schematic diagram of the structure of the base;

[0049] Figure 6 It is a schematic diagram of the structure of the pneumatic needle insertion cylinder body;

[0050] Figure 7 It is a schematic diagram of the structure of the cylinder body middle part and the cylinder body lower part;

[0051] Figure 8 It is a schematic diagram of the structure of the cylinder body upper part;

[0052] Figure 9 Structure diagram of force sensing sensor;

[0053] Figure 10 Structure diagram of locking device;

[0054] Figure 11 Control principle diagram of force sensing needle insertion device.

[0055] Wherein, 1-needle, 2-locking device, 3-force sensing sensor, 4-pneumatic needle insertion cylinder, 5-navigation device, 6-bracket, 7-fixed rack, 8-base, 21-bottom locking ring, 22-bottom protruding column, 23-bottom needle locking ring, 24-bottom needle slot, 31-bottom groove, 32-rectangular slot, 33-top groove, 34-glue injection hole, 35-optical fiber, 41-cylinder upper part, 42-cylinder middle part, 43-cylinder lower part, 411-top locking ring, 412-top needle locking ring, 413-top protruding column, 414-upper mounting hole, 415-upper sliding groove, 421-air pipe joint, 422-middle mounting hole, 423-middle sliding groove, 424-piston, 425-air chamber, 431-lower mounting hole, 51-navigation base, 52-navigation indicating ball, 53-second mounting hole, 54-positioning table, 61-first positioning groove, 62-first mounting hole, 63-second positioning groove, 64-quick release structure, 65-base mounting table, 71-wide sliding table, 72-upper positioning table, 73-thin sliding table, 74-tooth, 75-lower positioning table, 81-guiding hole, 82-mounting positioning part. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0057] As Figure 1 As shown in the structure, the present embodiment provides a nuclear magnetic compatible force sensing needle insertion device made of non-metallic material, which comprises a needle 1, a locking device 2, a force sensing sensor 3, a pneumatic needle insertion cylinder 4, a navigation device 5, a bracket 6, a fixed rack 7, and a base 8.

[0058] The bracket 6 and the base 8 are the basis of the whole force sensing needle insertion device; as Figure 1As shown, the bottom end of the bracket 6 is fixedly connected with the base 8, and the top end is fixedly connected with the navigation device 5; the navigation device 5 is located at the top of the force sensing needle insertion device, the puncture needle 1 and the force sensing sensor 3 are located at the front of the pneumatic needle insertion cylinder body 4, the fixed rack 7 is fixedly installed on the bracket 6, and the bottom end of the bracket 6 is fixedly connected with the base 8;

[0059] As shown in Figure 1 and Figure 2 , the navigation device 5 is used to realize the spatial positioning of the puncture needle 1, including a navigation base 51 and navigation indicating balls 52; the navigation base 51 can be a T-shaped structure, two ends of which are provided with two second mounting holes 53, and the tail of the navigation base 51 is provided with a positioning table 54; specifically, the positioning table 54 is inserted into the second positioning groove 63 of the bracket 6 in a shape-fitting manner, the positioning of the navigation device 5 and the bracket 6 is realized, and the second mounting hole 53 is fixed with the first mounting hole 62 of the bracket 6 by means of a screw. The three navigation indicating balls 52 are distributed in a triangular shape and are respectively installed at the three outer end portions of the navigation base 51; the bottom end of the navigation base 51 is fixedly installed on the bracket 6, and the top end is fixedly installed with the navigation indicating balls 52. The spatial positions of the three navigation indicating balls 52 can be captured by medical imaging or optical navigation equipment, and the establishment of a spatial coordinate system is completed based on the spatial positions of the three navigation indicating balls, and then the spatial position of the puncture needle insertion device is obtained. The navigation device can use the above navigation indicating balls 52 for navigation, or can use other markers, optical navigation or image recognition data navigation.

[0060] As shown in Figure 3 , one side of the bracket 6 is provided with first positioning grooves 61 at the upper and lower ends, the other side is provided with two quick release structures 64 at the middle position, and the top of the bracket 6 is provided with two first mounting holes 62 and a second positioning groove 63. Specifically, the quick release structure 64 can be a wedge-shaped block, which is used to connect with the external platform to realize quick replacement and fixation.

[0061] As shown in Figure 4 , the fixed rack 7 and the puncture needle 1 are both arranged in parallel with the bracket 6; the top of the fixed rack 7 is provided with an upper positioning table 72, the bottom is provided with a lower positioning table 75, one side of the fixed rack 7 is a wide sliding table 71, the other side is a thin sliding table 73, and the middle is provided with a plurality of teeth 74; the upper positioning table 72 and the lower positioning table 75 cooperate with the first positioning grooves 61 at the upper and lower ends of the bracket 6 to position the relationship between the bracket 6 and the fixed rack 7, and are fixedly connected by means of screws, rivets and other fasteners to fixedly install the fixed rack 7 on the bracket 6.

[0062] As shown in Figure 6 , Figure 7 , and Figure 8As shown, the pneumatic needle insertion cylinder 4 is sleeved on the outer circumferential side of the fixed rack 7 and connected with the gas supply system, and the engagement of the pneumatic needle insertion cylinder 4 and the fixed rack 7 is pneumatically controlled by the gas supply system, so as to realize the movement of the pneumatic needle insertion cylinder 4 along the fixed rack 7; the pneumatic needle insertion cylinder 4 comprises a cylinder upper part 41, a cylinder middle part 42 and a cylinder lower part 43 which are fixedly connected in sequence; the back of the cylinder upper part 41, i.e. the side facing the fixed rack 7, is provided with an upper sliding groove 415, the periphery is provided with a plurality of upper mounting holes 414, the front is provided with a top locking ring 411, the top of the top locking ring 411 is provided with a top puncture needle locking ring 412, the center of the top puncture needle locking ring 412 is provided with a top puncture needle guide groove for guiding the top of the puncture needle 1, and the inside of the top locking ring 411 is provided with a top protruding column 413. The cylinder middle part 42 is provided with four gas pipe joints 421 on both sides, the four gas pipe joints 421 are symmetrically distributed, the periphery is provided with a plurality of middle mounting holes 422, the inside of the cylinder middle part 42 is provided with a middle sliding groove 423 and two pistons 424, the piston 424 is in a U-shaped structure, the outside of the piston 424 is attached to the inner wall of the cylinder middle part 42, four gas chambers 425 are formed on both sides of the piston 424, the gas chambers 425 are formed between the outside wall of the piston 424 and the inner wall of the cylinder middle part 42, each gas chamber 425 is communicated with a gas pipe joint 421, and the volume of the gas chamber 421 is determined by the gas delivered by the gas pipe joint 421. The cylinder lower part 43 is provided with a plurality of lower mounting holes 431 around the periphery. The upper mounting holes 414, the middle mounting holes 422 and the lower mounting holes 431 are in position correspondence, and the cylinder upper part 41, the cylinder middle part 42 and the cylinder lower part 43 are connected and fixed by fasteners penetrating through the corresponding mounting holes, so as to ensure the airtightness of the gas chambers 425. The gas pipe joints 421 are connected with the gas supply system through external hoses, the gas chambers are supplied with gas through the gas supply system, the fixedly connected cylinder upper part 41 and cylinder middle part 42 form an installation space of the fixed rack 7, the upper sliding groove 415 is in contact with the wide sliding table 71, the middle sliding groove 423 is in contact with the thin sliding table 73, and the shape cooperation between the fixed rack 7 on both sides and the cylinder upper part 41 and the cylinder middle part 42 ensures that the pneumatic needle insertion cylinder 4 has only one direction of freedom of movement. The piston 424 is connected with the teeth of the fixed rack 7 through the teeth 74, the opening and closing of the four gas chambers 425 on both sides of the piston 424 are controlled, so as to control the engagement between the teeth of the piston 424 and the teeth 74 of the fixed rack 7 in sequence, realize the alternate engagement between the teeth of different pistons 424 and the teeth 74 of the fixed rack 7, and make the pneumatic needle insertion cylinder 4 move along the fixed rack 7.

[0063] As Figure 10As shown, the locking device 2 mainly includes a bottom locking ring 21 and a bottom puncture needle locking ring 23; a bottom boss 22 is provided inside the bottom locking ring 21, and a bottom puncture needle groove 24 for clamping the puncture needle 1 is provided at the center of the bottom puncture needle locking ring 23.

[0064] like Figure 9 As shown, the force sensor 3 includes a tubular body and three or four optical fibers 35 evenly distributed along the circumference of the tubular body. The optical fibers 35 extend axially along the tubular body and are fixedly connected to the inner wall of the tubular body. The sidewall of the tubular body is provided with multiple rectangular grooves 32 corresponding to each optical fiber 35. Each optical fiber 35 forms a first FBG sensor located in the rectangular groove 32 and a second FBG sensor located outside the rectangular groove. The first FBG sensor of the optical fiber 35 is used to achieve three-dimensional force sensing at the end, while the second FBG sensor of the optical fiber 35 is used to achieve temperature compensation. The top of the tubular body is provided with a top groove 33 and the bottom with a bottom groove 31. Near the bottom of the force sensor 3, multiple rectangular grooves 32 are provided. Near the top, a glue injection hole 34 is provided. Three or four optical fibers 35 are evenly distributed along the sidewall of the tubular body. The optical fibers 35 are bonded to the inner wall of the tubular body using glue injected through the glue injection hole 34.

[0065] Specifically, the top groove 33 cooperates with the top protrusion 413 to determine the relative position between the force sensor 3 and the upper portion 41 of the cylinder body. This position is locked by the top locking ring 411, which is mounted on the top outer circumference of the cylindrical body. The bottom groove 31 cooperates with the bottom protrusion 22 to determine the relative position between the force sensor 3 and the locking device 2. The cylindrical body is locked by the bottom locking ring 21, which is mounted tightly on the outer circumference of the cylindrical body. Due to the presence of the rectangular groove 32, the force sensor 3 bends when subjected to force. When the optical fiber 35 in the four walls of the force sensor 3 is stretched or compressed, the corresponding reflected wave changes, and shape or force is sensed by the change in wavelength. After the optical fiber 35 is placed inside the force sensor 3, glue is injected through the glue injection hole 34 to secure the optical fiber 35.

[0066] like Figure 5 As shown, the base 8 is provided with a guide hole 81 for guiding the puncture needle 1; it includes the puncture needle guide hole 81 and the base mounting positioning portion 82. Specifically, the bracket 6 is connected to the base mounting positioning portion 82 through the base mounting platform 65, thereby positioning the relative position of the base 8 and the bracket 6 and locking the connection.

[0067] The puncture needle 1 is guided through the guide hole 81 of the base 8 and the top puncture needle guide slot, and the relative position of the puncture needle 1 and the force sensing sensor 3 is fixed by the bottom puncture needle locking ring 23 of the locking device 2.

[0068] The force sensing needle insertion device described above uses two groups of cylinders to achieve half-tooth control accuracy. It can also use three groups of cylinders to achieve 1 / 3-tooth control accuracy, or four groups of pneumatic cylinders to achieve 1 / 4-tooth control accuracy, and so on.

[0069] In order to adapt to the special environmental requirements of CT and MRI, the force sensing needle insertion device described above adopts a pneumatic control scheme, as shown in Figure 11 The core of the scheme is to use a pneumatic stepper motor instead of a traditional electric motor, thereby solving the compatibility problem of the motor working in a high magnetic field environment. This design enables small navigation positioning surgical robots to be applied in a wide range of medical environments, especially in situations where image-assisted operations are required.

[0070] In the above system, the pneumatic device uses a bus communication protocol to transmit control signals, which are then sent to a relay, which further controls a solenoid valve. The solenoid valve will switch states at a specific frequency according to the received signals, thereby accurately controlling the start and stop of the pneumatic stepper motor, ensuring that the motor can move at the preset speed and force. The pneumatic stepper motor used in the present invention is optimized in performance, which can guarantee the high precision and repeatability of the puncture process.

[0071] The control system of the pneumatic stepper motor is to inject compressed air into the chamber by activating the corresponding pneumatic valve, thereby pushing the piston to move. By precisely controlling the opening and closing sequence and time of the valve, the motor can move linearly at a predetermined step frequency and direction.

[0072] As shown in Figure 11 The specific process is that in the application scenario of the surgical robot, the relay receives signals from the upper computer, which are carefully calculated and processed to ensure that they represent the correct surgical action instructions. After receiving the instructions, the relay changes state to control the solenoid valve connected to its output. The opening and closing of the solenoid valve directly controls the operation of the air pump, which in turn provides power to the pneumatic motor, which drives the puncture needle to move accurately. The coordination of this series of actions enables the surgical robot to perform delicate operations such as puncture, and the accuracy of these operations is directly related to the success rate of the operation.

[0073] In the control process, the relay not only responds to the control signal of the upper computer, but also may receive feedback from the sensor, such as the signal of the pressure sensor, to adjust the working state of the pneumatic motor, ensure the stability and safety of the operation. In addition, the bus communication in this process ensures the reliability of signal transmission and the stable operation of the whole system.

[0074] The sensing of the force sensing sensor 3 is realized based on the optical fiber Bragg grating (FBG) and based on optical fiber communication, and has nuclear magnetic compatibility. The driving of the needle insertion device is realized by a pneumatic device, which has nuclear magnetic compatibility. Therefore, the force sensing pneumatic needle insertion device designed in this paper has nuclear magnetic compatibility as a whole.

[0075] In addition, the present application can also realize the miniaturization of the device, and the volume can be controlled in a compact space of 40mmx30mmx25mm, which ensures that it can be easily integrated into various medical environments, especially in the internal space of medical equipment.

[0076] In terms of accuracy, the step length of the pneumatic device is determined by the width of the rack, which can be accurate to 0.25mm.

[0077] The above-mentioned force sensing needle insertion device not only enables the performance of the puncture robot to reach a new height in fine control, but also provides additional protection for patient safety. It enables the robot to more reliably assist the doctor to complete high-precision medical operations without interfering with electromagnetic sensitive equipment, whether in complex surgical procedures or in precise treatment, and can play an important role.

[0078] The above-mentioned force sensing needle insertion device includes a visual positioning module, a pneumatic needle insertion module and a force sensing module; the specific description of the above-mentioned force sensing needle insertion device is as follows, in the following description, the movement relationship of each component is described in the coordinate system shown in Figure 1 The negative direction of the puncture needle 1 is the Z-axis direction.

[0079] The pneumatic needle insertion cylinder 4 is connected to the pneumatic system through four air pipe joints 421 and hoses, and four pneumatic air inlet channels can be established. Two of the air inlet channels act on a piston 424, so that the piston 424 can realize horizontal Y-axis reciprocating movement. During the movement of the piston 424, the straight teeth of the piston 424 are in contact with the teeth 74 in the fixed rack 7, and the pneumatic needle insertion cylinder 4 moves in the Z-axis vertical direction. By designing the two sides of the piston 424 to be half a tooth pitch apart, when the left air inlet channel is filled with air, the piston 424 moves to the right, i.e. in the positive direction of the Y-axis, and through the contact with the fixed rack 7, the pneumatic needle insertion cylinder 4 moves in the negative direction of the Z-axis. Similarly, when the right air inlet channel is filled with air, the piston 424 moves to the left, i.e. in the negative direction of the Y-axis, and through the contact with the fixed rack 7, the pneumatic needle insertion cylinder 4 moves in the positive direction of the Z-axis. Therefore, by controlling the horizontal Y-axis reciprocating movement of the piston 424, the vertical Z-axis reciprocating movement of the pneumatic needle insertion cylinder 4 can be realized.

[0080] In addition, it can be noted that when the overall position of the pneumatic needle insertion cylinder 4 is moved upward, i.e. in the positive direction of the Z-axis, by a distance of one tooth, the movement direction of the piston 424 and the fixed rack 7 is reversed.

[0081] Based on this, in order to further realize the continuous movement of the pneumatic needle insertion cylinder 4 in a single direction, two groups of pistons 424 are arranged vertically in the Z-axis direction, and the distance between the two groups of pistons 424 is not an integer multiple of the number of teeth, for example, 5.5 tooth pitches. During needle insertion, first, the upper piston moves in the positive direction of the Y-axis, and at the same time, the lower piston moves in the negative direction of the Y-axis, so that the pneumatic needle insertion cylinder moves in the negative direction of the Z-axis by half a tooth. Then, the lower piston moves in the positive direction of the Y-axis, and the upper piston moves in the negative direction of the Y-axis, so that the pneumatic needle insertion cylinder moves in the negative direction of the Z-axis by half a tooth. By continuously performing the above periodic movement, the pneumatic needle insertion cylinder can realize continuous needle insertion in the negative direction of the Z-axis. Each periodic movement can realize a movement distance of one tooth of the pneumatic needle insertion cylinder. Therefore, the pneumatic needle insertion cylinder can realize step-by-step movement control of the piston and the fixed rack by half a tooth pitch, and realizes precise puncture needle depth control.

[0082] The force sensing sensor 3 is connected to the puncture needle 1 through the locking device 2, and is connected to the pneumatic needle insertion cylinder 4 through the upper part 41 of the cylinder, so that the force applied to the puncture needle 1 can be applied to the force sensing sensor 3.

[0083] As Figure 9As shown, the sensor can be arranged with three optical fibers 35, each of which is distributed with two fiber Bragg grating (FBG) sensors, located in the non-rectangular groove region and the rectangular groove region, respectively. The three FBGs on the three optical fibers in the rectangular groove region form one FBG group, denoted as FBGs-1. The three FBGs on the three optical fibers in the non-rectangular groove region form another FBG group, denoted as FBGs-2. The FBGs-2 are used to achieve temperature compensation of the sensor, and the FBGs-1 are used to achieve three-dimensional force sensing at the tip.

[0084] The modeling process of the force sensing sensor 3 is as follows:

[0085] Most of the operating force at the tip of the puncture needle is usually less than 5N. Therefore, assuming that the elastic deformation is small, the sensor can be assumed to be an Euler-Bernoulli beam, which is subjected to radial forces (F x and F y ) and axial force (F z ) at the micro-tip, generating linear proportional local elastic strain on each fiber grating. Then the Bragg wavelength shift of each fiber grating sensor can be expressed as:

[0086] Δλ i,j = X C i,j ·F x + Y C i,j ·F y + Z C i,j ·F z + ΔT C i,j ·ΔT,(i=1,2,3,j=1,2).

[0087] In the formula, Δλ i,j is the Bragg wavelength shift of fiber i in the jth FBG group. X C i,j , Y C i,j , Z C i,j and ΔT C i,j represent the linear relationship between the grating wavelength Δλ i,j and F x , F y , F z and temperature change ΔT, respectively.

[0088] Since both FBGs have the same diameter and length, ideally they are equally affected by temperature changes. However, since FBGs-2, which are used for auxiliary bending moment check and temperature compensation, have a different shape structure than FBGs-1, which are used for force sensing, it can be assumed that they are also affected differently by temperature, which can be expressed as:

[0089]

[0090] where, ΔT C1 and ΔT C2 are the effects on FBGs-2 and FBGs-1 respectively due to ΔT.

[0091] As can be seen from the figure, the rectangular slot structure we designed has mechanical characteristics similar in the X and Y axes, and is significantly different from the axial mechanical properties. Therefore, we divided the model into axial and radial parts for separate analysis.

[0092] For the radial force of the three-dimensional force sensor, FBGs-1, its three FBGs are affected by the same axial load:

[0093]

[0094] The grating deformation variable under the influence of axial load and temperature can be expressed as:

[0095]

[0096] The effect of temperature changes is eliminated by subtracting the common wavelength model from the Bragg wavelength of each fiber from FBGs-1 and from FBGs-2:

[0097]

[0098] The remaining wavelengths of the three FBGs are linearly related to the radial force. Therefore, the radial force experienced by the three-dimensional force sensor model can be expressed as:

[0099]

[0100] where is a linear matrix.

[0101] In order to make FBGs-1 more sensitive to axial force, a flexible structure was designed to increase the sensitivity of the sensor to axial force. However, at the same time, this causes FBGs-1 to be equally sensitive to radial force. Therefore, we need to eliminate the effect of radial force on axial force by

[0102]

[0103] ​Let Z C = [ Z C1 Z C2] T , ΔT C = [ ΔT C1 ΔT C2] T . Respectively carry out the optical fiber wavelength change under different stress at room temperature, the optical fiber wavelength change under different temperature without stress can be modified as:

[0104]

[0105] Thus can be obtained respectively Z C1, Z C2, ΔT C1, ΔT C2.

[0106] Using Z C and ΔT C, can be obtained:

[0107]

[0108] Thus the puncture force F z on the Z axis can be finally obtained.

[0109] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and the equivalent technologies thereof, the present application also intends to include these modifications and variations.

Claims

1. A nuclear magnetic field compatible force sensing needle insertion device, characterized in that: The application relates to a non-metallic material puncture needle device, which comprises a puncture needle, a locking device, a force sensing sensor, a pneumatic needle feeding cylinder, a navigation device, a support, a fixed rack and a base. One end of the support is fixedly connected with the base, and the other end is fixedly connected with the navigation device. The base is provided with a guide hole for guiding the puncture needle. The fixed rack is arranged in parallel with the support and is fixedly installed at both ends of the support. The pneumatic needle feeding cylinder is sleeved on the outer circumferential side of the fixed rack and is connected with a gas supply system. The force sensing sensor comprises a circular tubular body and three or four optical fibers which are uniformly distributed along the circumference of the circular tubular body. The puncture needle and one end of the circular tubular body are fixedly installed on the side of the pneumatic needle feeding cylinder away from the support and move along the fixed rack with the pneumatic needle feeding cylinder. The puncture needle is arranged in parallel with the fixed rack and is fixedly installed on the other end of the circular tubular body through the locking device and passes through the guide hole. The navigation device is used for realizing the spatial positioning of the puncture needle.

2. The force sensing needle access device of claim 1, wherein, The fixed rack is provided with a wide sliding platform on one side edge and a thin sliding platform on the other side edge, and a plurality of teeth are arranged in the middle of the two side faces. The pneumatic needle feeding cylinder comprises a cylinder upper part, a cylinder middle part and a cylinder lower part which are fixedly connected in sequence. The inner surface of the piston is provided with a plurality of teeth which are opposite to the teeth of the fixed rack. The opening and closing of the four air chambers are controlled by the gas supply system to realize the alternate engagement between the teeth of different pistons and the teeth of the fixed rack.

3. The force sensing needle access device of claim 2, wherein, The upper part of the cylinder is provided with a plurality of upper mounting holes in the circumference; the middle part of the cylinder is provided with a plurality of middle mounting holes in the circumference corresponding to the upper mounting holes; the lower part of the cylinder is provided with a plurality of lower mounting holes in the circumference corresponding to the upper mounting holes; the upper part of the cylinder, the middle part of the cylinder and the lower part of the cylinder are fixedly connected by fasteners passing through the upper mounting holes, the middle mounting holes and the lower mounting holes in sequence, so as to ensure the airtightness of each air chamber.

4. The force sensing needle access device of claim 2, wherein, The upper part of the cylinder is provided with a top locking ring on the side surface away from the middle part of the cylinder; the top of the top locking ring is fixedly connected with a top puncture needle locking ring, and a top puncture needle guide groove is arranged at the center of the top puncture needle locking ring; the top locking ring is sleeved on the outer circumferential side of the circular tubular body and fixedly connects the circular tubular body to the upper part of the cylinder; The locking device comprises a bottom locking ring locked to the outer circumferential side of the circular tubular body and a bottom puncture needle locking ring fixedly connected to the bottom locking ring; the center of the bottom puncture needle locking ring is provided with a bottom puncture needle groove for clamping the puncture needle; The top of the puncture needle is guided through the top puncture needle guide groove, and the puncture needle is fixedly installed on the pneumatic needle insertion cylinder through the bottom puncture needle locking ring.

5. The force sensing needle access device of claim 4, wherein, The inside of the top locking ring is provided with a top protruding column; the inside of the bottom locking ring is provided with a bottom protruding column; One end of the circular tubular body is provided with a top recess, and the other end is provided with a bottom recess; The top recess cooperates with the top protruding column in shape, so as to realize the positioning between the upper part of the cylinder and the top locking ring, and the top locking ring is locked; The bottom recess cooperates with the bottom protruding column in shape, so as to realize the positioning of the locking device, and the bottom locking ring is locked.

6. The force sensing needle access device of claim 1, wherein, The navigation device comprises a navigation base and three navigation indicating balls in a triangular distribution; One side of the navigation base is fixedly installed on the support, and the other side is fixedly installed with the navigation indicating balls; A space coordinate system is established based on the spatial positions of the three navigation indicating balls, so as to obtain the spatial position of the puncture needle.

7. The force sensing needle access device of claim 6, wherein, The support is provided with opposite first positioning grooves at the two ends of the side facing the fixed rack, and a quick release structure for realizing quick assembly and disassembly with an external platform is arranged at the middle part of the other side away from the fixed rack; One end of the fixed rack is provided with an upper positioning table, and the other end is provided with a lower positioning table; the upper positioning table is inserted and matched with the first positioning groove at one end of the support, and the lower positioning table is inserted and matched with the first positioning groove at the other end of the support, and the upper positioning table and the support are fixedly connected by fasteners.

8. The force sensing needle access device of claim 7, wherein, The support is provided with a first mounting hole and a second positioning groove at the end where the navigation base is installed; The navigation base is provided with a second mounting hole corresponding in position to the first mounting hole and a positioning table corresponding in position and cooperating in shape with the second positioning groove; The navigation base is provided with a second mounting hole corresponding in position to the first mounting hole and a positioning table corresponding in position and cooperating in shape with the second positioning groove; The navigation base and the support are positioned by the plug connection of the positioning table and the second positioning slot, and are fixedly connected by the fasteners installed in the corresponding first mounting hole and second mounting hole.

9. The force sensing needle access device of claim 1, wherein, The circular tubular body is provided with a plurality of glue injection holes. The optical fiber is bonded in the circular tubular body by the glue injected through the glue injection holes.

10. The force sensing needle access device of any of claims 1-9, wherein, The base is provided with a mounting positioning part. The support is provided with a base mounting table at the end of the base. The base mounting table is connected and locked with the mounting positioning part, so as to realize the positioning connection of the base and the support.

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