Two-axis manipulator for MRI-HIFU

Abstract

The utility model discloses a two -axis manipulator for MRI HIFU, including adopting translation - rotation double axle architecture, through limited degree of freedom and realizes the plane positioning and angle adjustment of HIFU transducer, adopts non - magnetic material to make, specifically including structure shell, rotation transmission mechanism, rotary frame, translation transmission mechanism and limiting mechanism, wherein, rotation transmission mechanism, rotary frame, translation transmission mechanism and limiting mechanism set up in structure shell, the utility model provides a two -axis manipulator for MRI HIFU, adopts translation - rotation double axle architecture, through limited degree of freedom and realizes the plane positioning and angle adjustment of HIFU transducer, utilizes non - magnetic material and drive scheme, realizes zero electromagnetic interference, cooperates PID algorithm and MRI temperature control data linkage, and response delay is less than 50ms, supports transducer quick replacement, adapts 3MHz 8MHz multiple frequency's HIFU probe, expands clinical application scene.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, and in particular to a two-axis robotic arm for MRI-HIFU. Background Technology

[0002] Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) is a revolutionary non-invasive treatment technology. It uses real-time MRI imaging to locate lesions and then precisely ablates tissue using ultrasound energy. It has been widely used in the clinical treatment of diseases such as uterine fibroids, prostate cancer, and bone tumors. Its core advantage lies in combining the high-resolution anatomical imaging and temperature monitoring capabilities of MRI with the non-invasive energy focusing capabilities of HIFU, providing patients with a safe and efficient treatment option.

[0003] Despite the promising future of MRgHIFU technology, the design of its mechanical positioning system still faces multiple bottlenecks: 1. Compatibility issues: Traditional multi-axis robotic arms often contain magnetic materials, leading to MRI imaging artifacts. Furthermore, electromagnetic drive devices are susceptible to interference from strong magnetic fields, failing to meet the safety requirements of 1.5T / 3T MRI environments. 2. The contradiction between degrees of freedom and precision: While existing six-axis robotic arms can achieve three-dimensional spatial positioning, the systems are complex and bulky, making flexible deployment within the narrow MRI aperture difficult. The cumulative errors from multiple joints also affect focal point positioning accuracy (typically requiring control within ±1mm). 3. Real-time response delay: MRI dynamic temperature feedback requires the robotic arm to rapidly adjust the focal point position to track tissue deformation, but traditional hydraulic / motor drive systems exhibit lag, resulting in reduced energy deposition efficiency. 4. Clinical operation limitations: Complex multi-axis systems require frequent calibration, extending treatment time (an average increase of 20-30 minutes), affecting patient tolerance and diagnostic efficiency. Summary of the Invention

[0004] In view of the aforementioned shortcomings of the prior art, the technical problem to be solved by this utility model is the compatibility issues of existing robotic arms. These include complex and bulky mechanical structures, inability to be flexibly deployed within the narrow MRI aperture, poor positioning accuracy, delayed real-time response, complex operation, and prolonged treatment time. This utility model provides a two-axis robotic arm for MRI-HIFU, employing a translational-rotational dual-axis architecture. It achieves planar positioning and angle adjustment of the HIFU transducer through limited degrees of freedom. Utilizing non-magnetic materials and a driving scheme, it achieves zero electromagnetic interference. Combined with a PID algorithm linked to MRI temperature control data, the response latency is <50ms. It supports rapid transducer replacement and is compatible with HIFU probes of various frequencies from 3MHz to 8MHz, expanding clinical application scenarios.

[0005] To achieve the above objectives, this utility model provides a two-axis manipulator for MRI-HIFU, comprising a translational-rotational dual-axis architecture, achieving planar positioning and angle adjustment of the HIFU transducer through limited degrees of freedom, and made of non-magnetic material; specifically including a structural shell, a rotary transmission mechanism, a rotary frame, a translational transmission mechanism, and a limiting mechanism; wherein, the rotary transmission mechanism, the rotary frame, the translational transmission mechanism, and the limiting mechanism are disposed within the structural shell;

[0006] The rotary transmission mechanism is connected to the rotary frame via gears. A translational transmission mechanism and a limiting mechanism are fixedly installed on the rotary frame. The rotary frame is configured to rotate around the outer shell of the structure. The rotary transmission mechanism controls the rotation of the rotary frame around the axis, and the translational transmission mechanism controls the forward and backward movement of the transmission rod. The limiting mechanism is used to restrict the position and range of the robot's rotation or movement.

[0007] Furthermore, the structural housing includes a rear cover plate, a rear acrylic sleeve, a middle acrylic sleeve, a front acrylic sleeve, a first bushing, a second bushing, a rotating plate fixing ring, a front cover plate, a left stop limit switch block, and a right stop limit switch block; wherein, the rotating plate fixing ring is fixedly connected to the inner side of the front cover plate, the front acrylic sleeve is fixedly connected to the front cover plate and the second bushing, the middle acrylic sleeve is fixedly connected to the second bushing and the first bushing, and the rear acrylic sleeve is fixedly connected to the first bushing and the rear cover plate; the front acrylic sleeve, the middle acrylic sleeve, and the rear acrylic sleeve are arranged sequentially; the left stop limit switch block and the right stop limit switch block are equipped with rotating plate fixing rings.

[0008] Furthermore, the rotary transmission mechanism includes a rotary gearbox, a first ultrasonic motor, a first encoder, and a rotary gearbox connecting plate; one side of the rotary gearbox is connected to the rotary gearbox connecting plate, and the other side is connected to the first ultrasonic motor, and the other side of the first ultrasonic motor is connected to the first encoder; the rotary gearbox is mounted to the semi-circular gear through gear engagement; the semi-circular gear and the rotary gearbox are located on the same side of the first bushing.

[0009] Furthermore, the rotary gearbox includes a rotary gearbox frame, a first gear, a second gear, a third gear, a fourth gear, and a gear shaft. The first gear, the second gear, and the third gear are disposed inside the rotary gearbox frame. The first gear is mounted and connected to the first ultrasonic motor through a shaped shaft hole. The first gear is connected to the second gear through a gear engagement. The second gear is connected to the third gear through a gear engagement. The third gear is connected to the fourth gear through the gear shaft. The fourth gear is connected to the semi-circular gear through a gear engagement. The second gear and the gear shaft are mounted inside the rotary gearbox frame through a shaft hole engagement.

[0010] Furthermore, the rotating frame includes a left connecting plate, a right connecting plate, a movable gearbox connecting plate, a rotating connecting plate, and a rotating transmission rear plate. The left and right connecting plates are arranged in parallel, with one end of the left and right connecting plates connected to the rotating connecting plate and the other end connected to the rotating transmission rear plate. The movable gearbox connecting plate is located between the left and right connecting plates and in the middle section of the left and right connecting plates.

[0011] Furthermore, the rotating connecting plate is mounted on the first bushing through a shaft hole, the moving gearbox connecting plate is mounted on the second bushing through a shaft hole, and the rotating transmission rear plate is mounted on the rotating plate fixing ring through a shaft hole.

[0012] Furthermore, the translational transmission mechanism includes a movable gearbox, a second ultrasonic motor, a second encoder, a transmission screw, a transmission nut, and a transmission rod. The movable gearbox is fixedly connected to the second ultrasonic motor, the second ultrasonic motor is fixedly connected to the second encoder, the movable gearbox is fixedly connected to the transmission screw, the transmission screw is connected to the transmission nut through a threaded connection, the transmission nut is fixedly connected to the transmission rod, and the transmission nut is fixedly connected to the rotary transmission rear plate through a transmission nut sleeve.

[0013] Furthermore, an upper saddle key is provided on the top of the transmission nut, and a lower saddle key is provided on the bottom of the transmission nut.

[0014] Furthermore, the mobile gearbox includes a pinion, a large gear, a transmission gear, and a mobile gearbox frame. The pinion, large gear, and transmission gear are located inside the mobile gearbox frame. The second ultrasonic motor drives the pinion, transmission gear, and large gear to mesh and rotate, thereby changing the speed and causing the transmission gear to rotate along with the transmission screw.

[0015] Furthermore, the pinion is connected to the second ultrasonic motor, and the transmission gear is connected to the transmission lead screw.

[0016] Technical effect

[0017] This invention provides a two-axis robotic arm for MRI-HIFU, employing a translational-rotational dual-axis architecture. It achieves planar positioning and angle adjustment of the HIFU transducer through limited degrees of freedom. The main structure is made of transparent PCTG modified engineering plastic, coupled with a piezoelectric ceramic motor, achieving zero electromagnetic interference and meeting the ASTM F2503 MRI safety standard. Through PID algorithm and linkage with MRI temperature control data, the response delay is <50ms. It supports rapid transducer replacement and is compatible with HIFU probes of various frequencies from 3MHz to 8MHz, expanding clinical application scenarios.

[0018] This invention provides a two-axis robotic arm for MRI-HIFU, which significantly improves the clinical applicability of the MRgHIFU system through structural simplification and technological innovation, thereby increasing treatment efficiency, shortening mechanical positioning time to within 5 minutes, reducing the single treatment cycle by 40%, reducing the number of parts by 60%, and making the manufacturing cost only 1 / 3 of the traditional multi-axis system; it can be adapted to 3T high field strength MRI and supports treatment of delicate areas.

[0019] The following will further explain the concept, specific structure and technical effects of this utility model in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of this utility model. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a two-axis robotic arm for MRI-HIFU, a preferred embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a two-axis robotic arm for MRI-HIFU, a preferred embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a rotary transmission mechanism for a two-axis manipulator used in MRI-HIFU, according to a preferred embodiment of this utility model.

[0023] Figure 4 This is a schematic diagram of a translational transmission mechanism for a two-axis manipulator used in MRI-HIFU, according to a preferred embodiment of this utility model.

[0024] Figure 5 This is a schematic diagram of a two-axis robotic arm for MRI-HIFU, a preferred embodiment of the present invention;

[0025] Figure 6 This is a cross-sectional view of a two-axis robotic arm for MRI-HIFU, which is a preferred embodiment of the present invention.

[0026] Among them, 100-structural shell, 200-rotary transmission mechanism, 300-rotary frame, 400-translational transmission mechanism, 500-limiting mechanism, 110-front acrylic sleeve, 120-middle acrylic sleeve, 130-rear acrylic sleeve, 140-rear cover plate, 150-first bushing, 160-second bushing, 170-rotating plate fixing ring, 171-left gear limit switch block, 172-right gear limit switch block, 180-front cover plate, 210-first ultrasonic motor, 211-first encoder, 220-rotary gearbox, 230-rotary gearbox connecting plate, 240-half-circular gear, 221-first gear, 222-second gear, 223-third gear, 224-gear shaft, 225-fourth gear, 226-rotary gearbox frame. 310-Rotating connecting plate, 320-Left connecting plate, 330-Right connecting plate, 340-Moving gearbox connecting plate, 350-Rotating transmission rear plate, 410-Second ultrasonic motor, 411-Second encoder, 420-Moving gearbox, 430-Transmission screw, 440-Transmission nut, 441-Upper saddle key, 442-Lower saddle key, 450-Transmission nut sleeve, 460-Transmission rod, 421-Moving gearbox frame, 421-Small gear, 423-Transmission gear, 424-Large gear, 510-Front translation limit support, 520-Rotation limit support, 530-Rear translation limit support, 511-Front translation limit switch, 521-Left rotation limit switch, 522-Right rotation limit switch, 531-Rear translation limit switch, 532-Swing rod. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0028] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the present invention with unnecessary detail.

[0029] like Figure 1-6As shown, this utility model provides a two-axis manipulator for MRI-HIFU, including a translational-rotational dual-axis architecture, which realizes the planar positioning and angle adjustment of the HIFU transducer through limited degrees of freedom, and is made of non-magnetic material; specifically, it includes a structural shell 100, a rotary transmission mechanism 200, a rotary frame 300, a translational transmission mechanism 400, and a limiting mechanism 500; wherein, the rotary transmission mechanism 200, the rotary frame 300, the translational transmission mechanism 400, and the limiting mechanism 500 are disposed within the structural shell 100;

[0030] The rotary transmission mechanism 200 is connected to the rotary frame 300 via gear engagement. The rotary frame 300 is fixedly equipped with a translational transmission mechanism 400 and a limiting mechanism 500. The rotary frame 300 is configured to rotate around the structural shell 100. The rotary transmission mechanism 200 controls the rotation of the rotary frame 300 around the axis. The translational transmission mechanism 400 controls the forward and backward movement of the transmission rod 460. The limiting mechanism 500 is used to limit the position and range of rotation or movement of the robot.

[0031] The structural housing 100 includes a rear cover plate 140, a rear acrylic sleeve 130, a middle acrylic sleeve 120, a front acrylic sleeve 110, a first bushing 150, a second bushing 160, a rotating plate fixing ring 170, a front cover plate 180, a left stop limit switch block 171, and a right stop limit switch block 172. The rotating plate fixing ring 170 is fixedly connected to the inner side of the front cover plate 180, and the front acrylic sleeve 110 is... The front cover plate 180 and the second bushing 160 are fixedly connected. The middle acrylic sleeve 120 is fixedly connected to the second bushing 160 and the first bushing 150. The rear acrylic sleeve 130 is fixedly connected to the first bushing 150 and the rear cover plate 140. The front acrylic sleeve 110, the middle acrylic sleeve 120, and the rear acrylic sleeve 130 are arranged sequentially. The left stop limit switch block 171 and the right stop limit switch block 172 are equipped with rotating plate fixing rings 170. The structural shell 100 is made of transparent material. Preferably, the structural shell 100 is made of modified engineering plastic, PCTG, which allows observation of the internal movement and avoids interference caused by improper installation. The first bushing 150 and the second bushing 160 are hollow structures.

[0032] The rotary transmission mechanism 200 includes a rotary gearbox 220, a first ultrasonic motor 210, a first encoder 211, and a rotary gearbox connecting plate 230. One side of the rotary gearbox 220 is connected to the rotary gearbox connecting plate 230, and the other side is connected to the first ultrasonic motor 210. The other side of the first ultrasonic motor 210 is connected to the first encoder 211. The rotary gearbox 220 is mounted to a semi-circular gear 240 via gear engagement. The rotary gearbox connecting plate 230 is fixed to the first bushing 150, and the semi-circular gear 240 is fixed to the rotary connecting plate 310. Specifically, the rotary gearbox 230 and the semi-circular gear 240 are located on the same side of the first bushing.

[0033] The rotary gearbox 220 includes a rotary gearbox frame 226, a first gear 221, a second gear 222, a third gear 223, a fourth gear 225, and a gear shaft 224. The first gear 221, the second gear 222, and the third gear 223 are disposed inside the rotary gearbox frame 226. The first gear 221 is connected to the first ultrasonic motor 210 through a shaped shaft hole. The first gear 221 is connected to the second gear 222 through a gear engagement. The second gear 222 is connected to the third gear 223 through a gear engagement. The third gear 223 is connected to the fourth gear 225 through the gear shaft 224. The fourth gear 225 is connected to the semi-circular gear 240 through a gear engagement. The second gear 222 and the gear shaft 224 are mounted inside the rotary gearbox frame 226 through a shaft hole engagement.

[0034] In this embodiment of the utility model, by controlling the rotation of the first ultrasonic motor 210, the first gear 221, the second gear 222, the third gear 223, and the fourth gear 225 are driven to mesh and rotate, thereby changing the speed and causing the semi-circular gear 240 to rotate along with the rotating frame 300. The first encoder 211 is used to detect the movement stroke of the first ultrasonic motor 210 for closed-loop control, as a closed-loop feedback control, to prevent the motor from moving too much or too little.

[0035] The rotating frame 300 includes a left connecting plate 320, a right connecting plate 330, a movable gearbox connecting plate 340, a rotating connecting plate 310, and a rotating transmission rear plate 350. The left connecting plate 320 and the right connecting plate 330 are arranged in parallel. One end of the left connecting plate 320 and the right connecting plate 330 is connected to the rotating connecting plate 310, and the other end is connected to the rotating transmission rear plate 350. The movable gearbox connecting plate 340 is located between the left connecting plate 320 and the right connecting plate 330 and is located in the middle section of the left connecting plate 320 and the right connecting plate 330.

[0036] The rotating connecting plate 310 is mounted on the first bushing 150 via a shaft hole, the movable gearbox connecting plate 340 is mounted on the second bushing 160 via a shaft hole, and the rotating transmission rear plate 350 is mounted on the rotating plate fixing ring 170 via a shaft hole. The rotating connecting plate 310 can rotate around the first bushing 150, the movable gearbox connecting plate 340 can rotate around the second bushing 160, and the rotating transmission rear plate 350 can rotate around the rotating plate fixing ring.

[0037] The translational transmission mechanism 400 includes a movable gearbox 420, a second ultrasonic motor 410, a second encoder 411, a transmission screw 430, a transmission nut 440, and a transmission rod 430. The movable gearbox 420 is fixedly connected to the second ultrasonic motor 410, the second ultrasonic motor 410 is fixedly connected to the second encoder 411, and the movable gearbox 420 is fixedly connected to the transmission screw 430. The transmission screw 430 is connected to the transmission nut 440 via a threaded connection. The transmission nut 440 is fixedly connected to the transmission rod 460, and the transmission nut 440 is fixedly connected to the rotary transmission rear plate 350 via a transmission nut sleeve 450. An upper key 441 is provided on the top of the transmission nut 440, and a lower key 442 is provided on the bottom of the transmission nut 440.

[0038] In this embodiment of the invention, by controlling the rotation of the second ultrasonic motor 410, the small gear 422, the transmission gear 423, and the large gear 424 are driven to mesh and rotate, thereby changing the speed so that the transmission gear 423 drives the transmission screw 430 to rotate. The second encoder 411 is used to detect the movement stroke of the second ultrasonic motor 410 for closed-loop control, as a closed-loop feedback control, to prevent the motor from moving too much or too little.

[0039] The mobile gearbox 420 includes a pinion 422, a large gear 424, a transmission gear 423, and a mobile gearbox frame 421. The pinion 422, large gear 424, and transmission gear 423 are disposed inside the mobile gearbox frame 421. The second ultrasonic motor 410 drives the pinion 422, transmission gear 423, and large gear 424 to rotate in gear meshing, thereby changing the speed and causing the transmission gear 423 to rotate in conjunction with the transmission screw 430. The pinion 422 is connected to the second ultrasonic motor 410, and the transmission gear 424 is connected to the transmission screw 430.

[0040] The limiting mechanism 500 includes a front translational limiting support 510, a rotational limiting support 520, and a rear translational limiting support 530.

[0041] The front translation limit support 510 is fixedly connected to the rotary transmission rear plate 350, and a front translation limit switch 511 is provided on the front translation limit support 510; the rotary limit support 520 is fixedly connected to the rotary transmission rear plate 350, a left rotary limit switch 521 is provided on the left side of the rotary limit support 520, and a right rotary limit switch 522 is provided on the right side of the rotary limit support 520; the rear translation limit support 530 is fixedly connected to the left connecting plate 320, a rear translation limit switch 531 is provided on the rear translation limit support 530, and a swing rod 532 is installed on the rear translation limit support 530 through a hinge, and the swing rod 532 is installed to the lower key 442 through a hinge.

[0042] When the rotating frame 300 rotates as a whole, the left rotation limit switch 521 or the right rotation limit switch 522 rotates to press the left stop limit switch block 171 or the right stop limit switch block 172 to achieve travel limit in the rotation direction; when the whole moves forward through the transmission nut 440, the upper saddle key 441 presses the forward translation limit switch 511 to achieve travel limit in the forward translation direction; when the whole moves backward through the transmission nut 440, the lower saddle key 442 drives the rocker arm 532 to rotate to press the backward translation limit switch 531 to achieve travel limit in the backward translation direction.

[0043] The two-axis manipulator of this utility model uses an external power supply to fix the first ultrasonic motor 210. The wires are routed directly from the opening in the rear cover plate 140. The second ultrasonic motor 410 has a rotational motion. The length of the wire required for rotation is reserved between the first bushing 150 and the second bushing 160, and it is fixed on the first bushing 150 and routed through the opening in the rear cover plate 140.

[0044] Both the first and second ultrasonic motors are independently motion-controlled. The first ultrasonic motor rotates the entire rotating frame 300 via gear transmission (the rotating transmission rear plate 350, the moving gearbox connecting plate 340, and the rotating connecting plate 310 of the rotating frame 300 are all mounted on the fixed front cover plate 180, the second bushing 160, and the first bushing 150 via shaft holes; the rotating transmission rear plate 350, the moving gearbox connecting plate 340, and the rotating connecting plate 310 can rotate inside the front cover plate 180, the second bushing 160, and the first bushing 150). The translation transmission mechanism 400 fixed inside the rotating frame 300 rotates the transmission rod 460 via the lead screw of the second ultrasonic motor. Before each movement, the impact limiting mechanism 500 ensures accurate initial position. The first encoder 211 and the second encoder 411 detect the rotation angle of the transmission shaft in real time and perform closed-loop feedback control to ensure accurate positioning.

[0045] This invention relates to a two-axis robotic arm for MRI-HIFU applied to a magnetic resonance imaging (MRI) bed. The two-axis robotic arm is fixed to the MRI bed body, and an ultrasonic transducer is fixedly installed on the robotic arm's transmission rod 460. The ultrasonic transducer is installed through a non-standard shaft and locked by a positioning screw. The ultrasonic transducer is inserted into the patient's body, and under the guidance of MRI, the robotic arm drives the ultrasonic transducer to move and rotate to perform focused ultrasound thermal ablation of the lesion tissue.

[0046] By linking the PID algorithm with MRI temperature control data, the response latency is less than 50ms. Specifically, MRI temperature measurement is equivalent to temperature detection, while the first and second encoders are equivalent to position detection. The PID algorithm calculates and predicts the movement in advance based on relevant temperature rise test data and transmission response data, achieving rapid response. Specifically, the PID algorithm acquires the temperature data from the MRI measurement and calculates the advance movement of the ultrasonic motor based on relevant test data. This allows the transducer to move to the next heating point before reaching the target heating temperature, ensuring that residual heat energy approaches the target temperature value indefinitely, preventing the transducer from remaining in one position for too long and overheating.

[0047] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A two-axis robotic arm for MRI-HIFU, characterized in that, The device employs a translation-rotation dual-axis architecture, achieving planar positioning and angle adjustment of the HIFU transducer through limited degrees of freedom, and is made of non-magnetic materials. Specifically, it includes a structural shell, a rotary transmission mechanism, a rotary frame, a translational transmission mechanism, and a limiting mechanism; wherein, the rotary transmission mechanism, the rotary frame, the translational transmission mechanism, and the limiting mechanism are disposed within the structural shell. The rotary transmission mechanism is connected to the rotary frame via gear engagement. The translational transmission mechanism and the limiting mechanism are fixedly mounted on the rotary frame. The rotary frame is configured to rotate around the structural shell. The rotary transmission mechanism controls the rotation of the rotary frame around the axis. The translational transmission mechanism controls the forward and backward movement of the transmission rod. The limiting mechanism is used to restrict the position and range of rotation or movement of the robot arm.

2. The two-axis robotic arm for MRI-HIFU as described in claim 1, characterized in that, The outer casing includes a rear cover plate, a rear acrylic sleeve, a middle acrylic sleeve, a front acrylic sleeve, a first bushing, a second bushing, a rotating plate fixing ring, a front cover plate, a left stop limit switch block, and a right stop limit switch block. The rotating plate fixing ring is fixedly connected to the inner side of the front cover plate. The front acrylic sleeve is fixedly connected to the front cover plate and the second bushing. The middle acrylic sleeve is fixedly connected to the second bushing and the first bushing. The rear acrylic sleeve is fixedly connected to the first bushing and the rear cover plate. The front acrylic sleeve, the middle acrylic sleeve, and the rear acrylic sleeve are arranged sequentially. The rotating plate fixing ring is installed on the left stop limit switch block and the right stop limit switch block.

3. A two-axis robotic arm for MRI-HIFU as described in claim 2, characterized in that, The rotary transmission mechanism includes a rotary gearbox, a first ultrasonic motor, a first encoder, and a rotary gearbox connecting plate; one side of the rotary gearbox is connected to the rotary gearbox connecting plate, and the other side is connected to the first ultrasonic motor, and the other side of the first ultrasonic motor is connected to the first encoder; the rotary gearbox is mounted to a semi-circular gear through gear engagement.

4. A two-axis robotic arm for MRI-HIFU as described in claim 3, characterized in that, The rotary gearbox includes a rotary gearbox frame, a first gear, a second gear, a third gear, a fourth gear, and a gear shaft. The first gear, the second gear, and the third gear are disposed inside the rotary gearbox frame. The first gear is connected to the first ultrasonic motor through a shaped shaft hole. The first gear is connected to the second gear through a gear engagement. The second gear is connected to the third gear through a gear engagement. The third gear is connected to the fourth gear through the gear shaft. The fourth gear is connected to the semi-circular gear through a gear engagement. The second gear and the gear shaft are mounted inside the rotary gearbox frame through a shaft hole engagement.

5. A two-axis robotic arm for MRI-HIFU as described in claim 2, characterized in that, The rotating frame includes a left connecting plate, a right connecting plate, a movable gearbox connecting plate, a rotating connecting plate, and a rotating transmission rear plate. The left connecting plate and the right connecting plate are arranged in parallel. One end of the left connecting plate and the right connecting plate is connected to the rotating connecting plate, and the other end is connected to the rotating transmission rear plate. The movable gearbox connecting plate is located between the left connecting plate and the right connecting plate and is located in the middle section of the left connecting plate and the right connecting plate.

6. A two-axis robotic arm for MRI-HIFU as described in claim 5, characterized in that, The rotating connecting plate is mounted on the first bushing through a shaft hole, the moving gearbox connecting plate is mounted on the second bushing through a shaft hole, and the rotating transmission rear plate is mounted on the rotating plate fixing ring through a shaft hole.

7. A two-axis robotic arm for MRI-HIFU as described in claim 5, characterized in that, The translational transmission mechanism includes a movable gearbox, a second ultrasonic motor, a second encoder, a transmission screw, a transmission nut, and a transmission rod. The movable gearbox is fixedly connected to the second ultrasonic motor, the second ultrasonic motor is fixedly connected to the second encoder, the movable gearbox is fixedly connected to the transmission screw, the transmission screw is connected to the transmission nut via a threaded connection, the transmission nut is fixedly connected to the transmission rod, and the transmission nut is fixedly connected to the rotary transmission rear plate via a transmission nut sleeve.

8. A two-axis robotic arm for MRI-HIFU as described in claim 7, characterized in that, The transmission nut has an upper saddle key on top and a lower saddle key on the bottom.

9. A two-axis robotic arm for MRI-HIFU as described in claim 7, characterized in that, The mobile gearbox includes a pinion, a large gear, a transmission gear, and a mobile gearbox frame. The pinion, the large gear, and the transmission gear are disposed inside the mobile gearbox frame. The second ultrasonic motor drives the pinion, the transmission gear, and the large gear to mesh and rotate, thereby changing the speed and causing the transmission gear to rotate along with the transmission screw.

10. A two-axis robotic arm for MRI-HIFU as described in claim 9, characterized in that, The pinion is connected to the second ultrasonic motor, and the transmission gear is connected to the transmission lead screw.

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