Under-actuated three-degree-of-freedom wrist rehabilitation robot

Abstract

The invention provides an under-actuated three-degree-of-freedom wrist rehabilitation robot, which aims to solve the problems of less degree of freedom, small motion range, single rehabilitation mode and the like of the traditional wrist rehabilitation equipment, and mainly comprises a horizontal rotating unit, a circumferential rotating unit, a sliding handle unit, a forearm supporting unit and the like, a horizontal joint motor and a circumferential direct current motor are adopted as driving elements, and three-degree-of-freedom rehabilitation movement including wrist flexion / extension, wrist ulnar deflection / radial deflection and forearm inward rotation / outward rotation is achieved. A patient puts the forearm on the supporting unit, grasps the sliding handle, selects a corresponding rehabilitation mode and sets a proper rehabilitation range and motion trail, and the robot can conduct passive and active rehabilitation training on the wrist joint. The encoder and the torque sensor are arranged in the driving element, in the rehabilitation training process, the movement range, the movement speed and the man-machine interaction torque of the wrist joint are sensed in real time, and the rehabilitation effect can be evaluated in a numeralization mode. According to the wrist rehabilitation robot, only two driving motors are adopted, three-degree-of-freedom rehabilitation movement can be achieved, and the wrist rehabilitation robot has the advantages of being compact in structure, low in cost and high in information sensing capacity.

Description

Technical Field

[0001] This invention belongs to the field of medical technology and is an underactuated three-degree-of-freedom wrist rehabilitation robot. Background Technology

[0002] Currently, wrist rehabilitation robots both domestically and internationally are mainly divided into two categories: rigid and flexible. Rigid wrist rehabilitation robots, typically represented by RiceWrist-S from Rice University, MIT-MANUS from MIT, EFW Exo II from Yanshan University, and the three-degree-of-freedom flexible parallel robot from the University of Macau, possess significant advantages such as high motion accuracy and strong load capacity, but generally suffer from obvious defects such as bulky mechanisms and poor instantaneous center of motion matching. Flexible wrist rehabilitation robots, such as Exo-Wrist from Seoul National University and the bionic wrist rehabilitation robot from the Shenyang Institute of Automation, Chinese Academy of Sciences, have successfully achieved lightweight design, but are limited by the technical bottleneck of insufficient joint output torque. Based on this, the underactuated three-degree-of-freedom wrist rehabilitation robot designed in this invention works together to achieve multi-directional rehabilitation movements such as flexion, extension, rotation, and lateral flexion.

[0003] The wrist joint is the most flexible and frequently used joint in the human body. Accidents, indirect violence, and excessive stretching can easily cause joint damage, and stroke can also easily lead to loss of hand function. Traditional one-on-one rehabilitation treatment consumes a lot of human, material, and financial resources. Wrist rehabilitation robots have emerged to meet the needs of high-intensity, long-term treatment.

[0004] Compared with the prior art, the beneficial effects of the present invention are: (1) The encoder and torque sensor are built into the drive element, and the range of motion, speed of movement and human-machine interaction torque of the wrist joint are sensed in real time during rehabilitation training, so that the rehabilitation effect can be numerically evaluated; (2) The wrist rehabilitation robot uses only two drive motors, which can realize three degrees of freedom rehabilitation movement, and has the advantages of compact structure, low cost and strong information perception capability; (3) The open wearable structure is adopted, which makes it convenient for patients to wear the device. Summary of the Invention

[0005] The purpose of this invention is to provide an underactuated three-degree-of-freedom wrist rehabilitation robot to achieve the above-mentioned functions and objectives.

[0006] An embodiment of the present invention provides an underactuated three-degree-of-freedom wrist rehabilitation robot. The robot is characterized by its ability to perform three-degree-of-freedom rehabilitation movements, including wrist flexion / extension, ulnar / radial deviation, and forearm internal / external pronation. It mainly comprises a circumferential rotation unit, a horizontal rotation unit, a sliding handle unit, and a forearm support unit. It uses a circumferential DC motor and a horizontal articulated motor as driving elements, enabling passive and active rehabilitation training of the wrist joint. During rehabilitation training, it can sense the range of motion, movement speed, and human-machine interaction torque of the wrist joint in real time, allowing for numerical evaluation of the rehabilitation effect.

[0007] Furthermore, the circumferential rotation unit is responsible for wrist ulnar / radial deviation and forearm pronation / external rotation movements during wrist rehabilitation exercises. This unit mainly consists of a circumferential DC motor, a front gear guide ring, a power gear shaft, a power gear, a rear gear guide ring, and a driven semi-ring gear. The circumferential DC motor is mounted on the outside of the front gear guide ring using a fixed flange, and a motor housing is also installed on the outside of the circumferential DC motor to ensure the overall aesthetic simplicity of the circumferential rotation unit. A bearing end cover is installed on the outside of the rear gear guide ring, and a bearing is installed in the inner hole of the bearing end cover. The upper parts of both the front and rear gear guide rings are semi-ring-shaped open structures, and the lower parts are approximately hollow cubes with rectangular grooves at the bottom. After the two are installed and closed, the upper... The lower part forms an arc groove, and the driven half-ring gear is a semi-ring rack that can be installed inside it. The lower part forms a closed cavity, and the power gear shaft, power gear and other components are located on the same axis inside the cavity. The output end of the circumferential DC motor is inserted into the transmission hole at the front end of the power gear shaft, and there is no bearing at this end. The rear end of the power gear shaft is fitted with a bearing installed in the inner hole of the bearing end cover. The power gear is fixed on the power gear shaft by means of a shaft elastic retaining ring, shaft shoulder and key, and meshes with the driven half-ring gear. The upper two ends of the outer side of the rear gear guide ring are equipped with symmetrical limiting plates, which can limit the rotation range of the driven half-ring gear by blocking the stop plate installed in the lower part of the driven half-ring gear.

[0008] Furthermore, the horizontal rotation unit is responsible for flexion / extension and ulnar / radial deviation of the wrist during wrist rehabilitation exercises. It consists of a circumferential rotation unit base, an adapter plate, and a horizontal joint motor. The adapter plate is installed between the rotor surface of the horizontal joint motor and the circumferential rotation unit base. Both the adapter plate and the circumferential rotation unit base rotate with the rotor of the horizontal joint motor. Both are thin circular plates. A front gear guide ring and a rear gear guide ring are installed on the upper surface of the circumferential rotation unit base so that the horizontal rotation unit drives the circumferential rotation unit to rotate in the horizontal direction.

[0009] Furthermore, the sliding handle unit consists of a sliding grip, a flexible wrist pad, a slider, a guide rail, and a guide rail box. The guide rail box and the flexible wrist pad are fixed to the double-threaded hole inside the driven half-ring gear with the same screws. The guide rail and the slider are installed inside the guide rail box cavity. The slider is connected to the sliding grip fixing seat and moves synchronously. The guide rail box cover is fixedly fitted to the guide rail box. A solid rubber plug is installed on the top of the sliding grip and fixed to the square platform of the sliding grip fixing seat below. The square platform of the sliding grip fixing seat extends from the hollow part of the guide rail box cover and slides with the strip hollow part of the guide rail box cover as a guide.

[0010] Furthermore, the forearm support unit is used to support the patient's forearm during medical rehabilitation. It mainly consists of a control box, a control box base, a control box bottom plate, and a forearm support plate. The forearm support plate has a uniform cross-section, and the cross-section is approximately three semi-circular arcs tangent to each other. Long holes on both sides pass through the straps. The bottom of the forearm support plate is embedded in the upper surface of the control box. During the rehabilitation training preparation stage, the patient places their forearm on the forearm support plate, grasps the sliding handle, and tightens the straps around their forearm. The control panel issues start and stop commands to the electronic control components. The commands are transmitted to the circumferential rotation unit and the horizontal rotation unit through the lines in the waterproof connector, and the training begins.

[0011] Furthermore, the device is equipped with two encoders and two torque sensors to accurately monitor the patient's wrist in real time during rehabilitation training, including wrist flexion / extension, ulnar / radial deviation, and forearm internal / external pronation. The encoders and torque sensors are integrated into the tail end of the circumferential DC motor and the bottom of the horizontal joint motor, respectively. The encoder and torque sensor at the tail end of the circumferential DC motor monitor the torque and motion angle of the patient during forearm internal / external pronation rehabilitation, while the torque sensor at the bottom of the circumferential DC motor monitors the torque and motion angle of the patient during ulnar / radial deviation and wrist flexion / extension. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is an axonometric view of an underactuated three-DOF wrist rehabilitation robot. Figure 2 This is an axonometric view of the extreme position of an underactuated three-DOF wrist rehabilitation robot. Figure 3 This is an exploded view of the horizontal rotating unit and the sliding handle unit; Figure 4 This is an exploded view of a circumferentially rotating element; Figure 5 This is an exploded view of the forearm support unit; Figure 6 This is a partial view of a hard-constrained underactuated three-degree-of-freedom wrist rehabilitation robot. Figure 7 This is a partial view of a limiting boss on an underactuated three-degree-of-freedom wrist rehabilitation robot. Among them, 1. A subactuated three-degree-of-freedom wrist rehabilitation robot; 2. A circumferential rotation unit; 3. A horizontal rotation unit; 4. A sliding handle unit; 5. A forearm support unit; 6. A motor housing; 7. A circumferential DC motor; 8. A fixed flange; 9. A front gear guide ring; 10. An elastic retaining ring for the shaft; 11. A power gear shaft; 12. A power gear; 13. A bearing; 14. A bearing end cover; 15. A stop plate; 16a. A left limiting plate; 16b. A right limiting plate; 17. A solid rubber plug; 18. A sliding grip; 19. A flexible wrist mechanism. 20. Pad; 21. Sliding grip mounting base; 22. Slider; 23. Guide rail box cover; 24. Guide rail; 25. Rear gear guide ring; 26. Driven half-ring gear; 27. Circumferential rotation unit base; 28. Adapter plate; 29. ​​Horizontal joint motor; 30. Strap; 31. Waterproof connector; 32. Control box; 33. Control box base; 34. Control box bottom plate; 35. Control panel; 36. Electrical control components; 37. Forearm support plate; 38. Base brake pad; 38a. Left limit boss; 38b. Right limit boss. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Example: Referring to Figures 1-2, the purpose of this invention is to provide an underactuated three-degree-of-freedom wrist rehabilitation robot to achieve the above-mentioned functions and objectives.

[0016] This example provides an underactuated three-degree-of-freedom wrist rehabilitation robot to address the problems of limited degrees of freedom, small range of motion, and single rehabilitation mode in traditional wrist rehabilitation devices. Figure 1As shown, this underactuated three-degree-of-freedom wrist rehabilitation robot mainly includes a circumferential rotation unit 2, a horizontal rotation unit 3, a sliding handle unit 4, and a forearm support unit 5. It can select the appropriate rehabilitation mode, set the appropriate rehabilitation range and motion trajectory according to the patient's actual situation. It uses a circumferential DC motor 7 and a horizontal joint motor 29 as driving elements to realize three-degree-of-freedom rehabilitation movements including wrist flexion / extension, wrist ulnar / radial deviation, and forearm internal / external pronation. It can sense the range of motion, movement speed, and human-machine interaction torque of the wrist joint in real time, and can perform numerical evaluation of rehabilitation effect.

[0017] refer to Figures 1 to 3 The circumferential rotation unit 2 is responsible for wrist ulnar / radial deviation and forearm pronation / external rotation movements during wrist rehabilitation exercises. It is driven by the circumferential DC motor 7, and the patient's training status is fed back through the integrated encoder and torque sensor at its tail end. The screw passes through the front gear guide ring 9 and the fixing flange 8 on the inside and is inserted into the threaded hole of the circumferential DC motor 7 to fix it. At the same time, the motor housing 6 is installed on the outside of the circumferential DC motor 7 to ensure the overall aesthetics and simplicity of the circumferential rotation unit 2. The bearing end cover 14 is fixed to the outside of the rear gear guide ring 25 by screws. The bearing 13 that matches the power gear shaft 11 is installed in the inner hole of the bearing end cover 14.

[0018] The front gear guide ring 9 and the rear gear guide ring 25 are closed and installed, with accurate fit ensured by fixing pins on both sides. The upper part of the front gear guide ring 9 and the rear gear guide ring 25 are both semi-circular open structures, and the lower part is approximately hollow cube-shaped with a rectangular groove at the bottom. After the two are installed and closed, the upper part forms an arc groove. The driven semi-circular gear 26 is a semi-circular rack that can be installed inside it. The upper two ends of the outer side of the rear gear guide ring 25 are equipped with symmetrically distributed left limit plates 16a and right limit plates 16b, which can block the stop plate 15 installed in the lower part of the driven semi-circular gear 26 to limit the rotation range of the driven semi-circular gear 26. The limiting effect of the left and right limit plates 16a and 16b on the stop plate 15 can ensure that the driven semi-circular gear 26 can rotate within a range of ±90° along the arc groove trajectory. The data line of the circumferential DC motor 7 passes through the rectangular groove at the bottom of the front gear guide ring 9 and the rear gear guide ring 25 and is pressed, and is connected to the control box 32 by the waterproof connector 31.

[0019] The power gear shaft 11 and power gear 12 are located on the same axis in the lower cavity after the front gear guide ring 9 and the rear gear guide ring 25 are closed. The output end of the circumferential DC motor 7 is inserted into the transmission hole at the front end of the power gear shaft 11, and there is no bearing at this end. The rear end of the power gear shaft 11 is fitted with the bearing 13 installed in the inner hole of the bearing end cover 14. After the rehabilitation training preparation stage is completed, the circumferential DC motor 7 receives the instruction sent by the electronic control element 36 and rotates clockwise or counterclockwise. The power gear 12 is supported by the shaft elastic retaining ring 10, the shaft shoulder, and the shaft shoulder. The key is fixed on the power gear shaft 11 and meshes with the driven half-ring gear 26. Power is transmitted from the power gear shaft 11 to the power gear 12 through the key, which in turn drives the driven half-ring gear 26 meshing with the power gear 12 to move. When the driven half-ring gear 26 rotates repeatedly at ±90° under the monitoring of the encoder and torque sensor at the tail of the circumferential DC motor 7, it is for forearm internal / external rotation exercise training. When the driven half-ring gear 26 is kept at +90° or -90°, it can be used in conjunction with the horizontal rotation unit 3 to perform wrist ulnar / radial deviation exercise training.

[0020] refer to Figures 1 to 4 , Figure 6 The horizontal rotation unit 3 is responsible for flexion / extension and ulnar / radial deviation of the wrist during wrist rehabilitation exercises. The adapter plate 28 is installed between the rotor surface of the horizontal joint motor 29 and the circumferential rotation unit base 27. The adapter plate 28 and the circumferential rotation unit base 27 move synchronously with the rotor of the horizontal joint motor 29. Both are circular thin plates. The horizontal joint motor 29 is fixed to the front opening of the control box 32 by the threaded hole on the stator surface of the horizontal joint motor 29. The adapter plate 28 and the circumferential rotation unit base 27 pass through the front opening of the control box. The circumferential rotation unit 2 is installed and fixed on the upper surface of the circumferential rotation unit base 27 by the threaded holes at the lower ends of the front gear guide ring 9 and the rear gear guide ring 25. At the same time, the base brake plate 38 is installed on the circumferential rotation unit base 27. The rotation range of the horizontal rotation unit 3 is limited by the left limiting boss 38a and the right limiting boss 38b at both ends of the front opening of the control box 32.

[0021] After the rehabilitation training preparation phase is completed, the horizontal joint motor 29 receives the command sent by the electronic control element 36 and rotates clockwise or counterclockwise. The power is transmitted to the circumferential rotation unit 2 by the adapter plate 28 and the circumferential rotation unit base 27, so that the horizontal rotation unit 3 drives the circumferential rotation unit 2 to rotate in the horizontal direction. Under the monitoring of the encoder and torque sensor at the bottom of the horizontal joint motor 29, when the driven half ring gear is centered at 0°, the horizontal joint motor performs ±50° movement, which is a wrist flexion / extension training movement. When the driven half ring gear is kept at +90° or -90°, the horizontal joint motor performs ±50° movement, which is a wrist ulnar deviation / radial deviation training movement.

[0022] refer to Figure 1 Image to Figure 3 The sliding handle unit 4 is responsible for providing guiding force to the wrist during rehabilitation training. The guide rail box 24 and the wrist flexible pad 19 are fixed to the double threaded hole on the inner side of the driven half ring gear 26 with the same screw. The guide rail 23 and the slider 21 are installed in the cavity of the guide rail box 24. The slider 21 is connected to the sliding grip fixing seat 20 and moves synchronously. The guide rail box cover 22 is fixedly attached to the guide rail box 24. A solid rubber plug 17 is installed on the top of the sliding grip 18 and fixed to the square platform of the sliding grip fixing seat 20 below. The square platform of the sliding grip fixing seat 20 extends from the hollow part of the guide rail box cover 22 and slides with the strip hollow part of the guide rail box cover 22 as a guide. During the preparation stage of wrist rehabilitation training, the patient holds the sliding grip 18 with their hand and presses the solid rubber stopper 17 with their thumb. The sliding grip 18 is adjusted to a suitable position so that the patient's wrist is on the wrist flexible pad 19. Due to different patient conditions, the sliding grip 18 may slide in different ways during training, but it will not exceed the guiding range of the guide rail cover 22.

[0023] refer to Figure 5 The forearm support unit 5 is used to support the patient's forearm during medical rehabilitation. The forearm support plate 37 has a uniform cross-section, and the cross-section is approximately three semi-circular arcs tangent to each other. The strap 30 passes through the long holes on both sides. The bottom of the forearm support plate 37 is embedded in the upper surface of the control box 32. During the rehabilitation training preparation stage, the patient places the forearm on the forearm support plate 37, holds the sliding handle 18 and adjusts it to a suitable rehabilitation training position. The strap 30 is then used to tighten the forearm. After all other matters are completed, rehabilitation training can begin. The control panel 35 issues equipment start and stop commands to the electrical control component 36. After the circumferential DC motor 7 is integrated with its own encoder and torque sensor lead-out lines, it first passes through the rectangular groove at the bottom after the front gear guide ring 9 and the rear gear guide ring 25 are closed. Then, it enters the control box 32 through the waterproof connector 31 at the top of the control box 32 and connects to the electrical control component 36. The control panel 35 and the electrical control component 36 are integrated into the control box 32, making reasonable use of the internal space of the control box 32 and ensuring the overall neatness of the equipment.

[0024] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. An underactuated three-degree-of-freedom wrist rehabilitation robot, used to solve the problems of limited degrees of freedom, small range of motion, and single rehabilitation mode in traditional wrist rehabilitation devices, characterized in that: The underactuated three-degree-of-freedom wrist rehabilitation robot includes a circumferential rotation unit (2), a horizontal rotation unit (3), a sliding handle unit (4), and a forearm support unit (5). It uses a circumferential DC motor (7) and a horizontal joint motor (29) as driving elements to realize three-degree-of-freedom rehabilitation movements including wrist flexion / extension, wrist ulnar / radial deviation, and forearm internal / external pronation. The patient places their forearm on the forearm support unit (5), holds the sliding handle (18), selects the corresponding rehabilitation mode, sets the appropriate rehabilitation range and movement trajectory, and performs passive and active rehabilitation training on the wrist joint according to the corresponding instructions. The circumferential rotation unit (2) is responsible for wrist ulnar / radial deviation and forearm pronation / external rotation movements in wrist rehabilitation exercises. This unit mainly consists of a circumferential DC motor (7), a front gear guide ring (9), a power gear shaft (11), a power gear (12), a rear gear guide ring (25), and a driven half-ring gear (26). The circumferential DC motor (7) is installed on the outside of the front gear guide ring (9) with a fixed flange (8). At the same time, the motor housing (6) is installed on the outside of the circumferential DC motor (7) to ensure the overall aesthetics and simplicity of the circumferential rotation unit (2). The bearing end cover (14) is installed on the outside of the rear gear guide ring (25). The bearing end cover (14) has a bearing (13) installed in the inner hole of the bearing end cover (14). The upper part of the front gear guide ring (9) and the rear gear guide ring (25) are both semi-ring open structures, and the lower part is approximately hollow cube in shape with a rectangular groove at the bottom. After the two are installed and closed, the upper part forms an arc. The groove, the driven half ring gear (26) is a semi-ring rack, which can be installed in it, and the lower part forms a closed cavity. The power gear shaft (11), power gear (12) and other components are located on the same axis in the cavity. The output end of the circumferential DC motor (7) is inserted into the transmission hole at the front end of the power gear shaft (11), and there is no bearing at this end. The rear end of the power gear shaft (11) is fitted with the bearing (13) installed in the inner hole of the bearing end cover (14). The power gear (12) is fixed on the power gear shaft (11) by means of the shaft elastic retaining ring (10), shaft shoulder and key, and meshes with the driven half ring gear (26) from top to bottom. The upper two ends of the outer side of the rear gear guide ring (25) are equipped with symmetrical limiting plates (16a, 16b), which can limit the rotation range of the driven half ring gear (26) by blocking the stop plate (15) installed in the lower part of the driven half ring gear (26). The horizontal rotation unit (3) is responsible for flexion / extension and ulnar / radial deviation of the wrist in wrist rehabilitation exercises. It consists of a circumferential rotation unit base (27), a transition plate (28), and a horizontal joint motor (29). The transition plate (28) is installed between the rotor surface of the horizontal joint motor (29) and the circumferential rotation unit base (27). The transition plate (28) and the circumferential rotation unit base (27) rotate with the rotor of the horizontal joint motor (29). Both are circular thin plates. The front gear guide ring (9) and the rear gear guide ring (25) are installed on the upper surface of the circumferential rotation unit base (27) so that the horizontal rotation unit (3) drives the circumferential rotation unit (2) to rotate in the horizontal direction. The sliding handle unit (4) consists of a sliding grip (18), a wrist flexible pad (19), a slider (21), a guide rail (23), and a guide rail box (24). The guide rail box (24) and the wrist flexible pad (19) are fixed to the double threaded hole inside the driven half-ring gear (26) with the same screw. The guide rail (23) and the slider (21) are installed in the cavity of the guide rail box (24). The slider (21) is connected to the sliding grip fixing seat (20) and moves synchronously. The guide rail box cover (22) is fixedly fitted to the guide rail box (24). A solid rubber plug (17) is installed above the sliding grip (18) and fixed below it on the square platform of the sliding grip fixing seat (20). The square platform of the sliding grip fixing seat (20) extends from the hollow part of the guide rail box cover (22) and slides with the strip hollow part of the guide rail box cover (22) as a guide. The forearm support unit (5) is used to support the patient's forearm during medical rehabilitation. It is mainly composed of a control box (32), a control box base (33), a control box bottom plate (34), and a forearm support plate (37). The forearm support plate (37) has a uniform cross section and the cross section is a structure of three semi-circular arcs tangent to each other. The strap (30) passes through the long holes on both sides. The bottom of the forearm support plate (37) is embedded in the upper surface of the control box (32). During the rehabilitation training preparation stage, the patient places his forearm on the forearm support plate (37), holds the sliding handle (18) with his hand, and the strap (30) tightens the forearm. The control panel (35) issues equipment start and stop commands to the electrical control components (36). The circuit is led from the waterproof connector (31) on the top of the control box to the circumferential rotation unit (2) and the horizontal rotation unit (3) to start the training.

2. The underactuated three-degree-of-freedom wrist rehabilitation robot according to claim 1, characterized in that: The circumferential rotary unit (2) is mainly composed of a circumferential DC motor (7), a front gear guide ring (9), a power gear shaft (11), a power gear (12), a rear gear guide ring (25), and a driven half-ring gear (26). The circumferential DC motor (7) is installed on the outside of the front gear guide ring (9) using a fixed flange (8). At the same time, a motor housing (6) is installed on the outside of the circumferential DC motor (7) to ensure the overall aesthetics and simplicity of the circumferential rotary unit (2). A bearing end cover (14) is installed on the outside of the rear gear guide ring (25). A bearing (13) is installed in the inner hole of the bearing end cover (14). The upper part of both the front gear guide ring (9) and the rear gear guide ring (25) is a semi-ring open structure, and the lower part is approximately a hollow cube with a rectangular groove at the bottom. After the two are installed and closed, an arc groove is formed on the upper part. The driven half-ring gear (26) is A semi-ring rack can be installed inside it, forming a closed cavity at the bottom. The power gear shaft (11), power gear (12) and other components are located on the same axis inside the cavity. The output end of the circumferential DC motor (7) is inserted into the transmission hole at the front end of the power gear shaft (11), and there is no bearing at this end. The rear end of the power gear shaft (11) is fitted with the bearing (13) installed in the inner hole of the bearing end cover (14). The power gear (12) is fixed on the power gear shaft (11) by means of a shaft elastic retaining ring (10), a shaft shoulder, and a key, and meshes with the driven semi-ring gear (26) from top to bottom. The upper two ends of the outer side of the rear gear guide ring (25) are equipped with symmetrical limiting plates (16a, 16b), which can limit the rotation range of the driven semi-ring gear (26) by blocking the stop plate (15) installed in the lower part of the driven semi-ring gear (26).

3. The underactuated three-degree-of-freedom wrist rehabilitation robot according to claim 1, characterized in that: The horizontal rotating unit (3) consists of a circumferential rotating unit base (27), a transition plate (28), and a horizontal joint motor (29). The transition plate (28) is installed between the rotor surface of the horizontal joint motor (29) and the circumferential rotating unit base (27). The transition plate (28) and the circumferential rotating unit base (27) rotate with the rotor of the horizontal joint motor (29). Both are circular thin plates. The front gear guide ring (9) and the rear gear guide ring (25) are installed on the upper surface of the circumferential rotating unit base (27) so that the horizontal rotating unit (3) drives the circumferential rotating unit (2) to rotate in the horizontal direction.

4. The underactuated three-degree-of-freedom wrist rehabilitation robot according to claim 1, characterized in that: The forearm support unit (5) is mainly composed of a control box (32), a control box base (33), a control box bottom plate (34), and a forearm support plate (37). The forearm support plate (37) has a uniform cross section, and the cross section is approximately three semi-circular arcs tangent to each other. The strap (30) passes through the long holes on both sides. The bottom of the forearm support plate (37) is embedded in the upper surface of the control box (32). During the rehabilitation training preparation stage, the patient places his forearm on the forearm support plate (37), holds the sliding handle (18) with his hand, and the strap (30) tightens the forearm. The control panel (35) issues equipment start and stop commands to the electrical control components (36). The circuit is led from the waterproof connector (31) on the top of the control box to the circumferential rotation unit (2) and the horizontal rotation unit (3) to start training.

5. The underactuated three-degree-of-freedom wrist rehabilitation robot according to claim 1, characterized in that: The wrist rehabilitation robot is equipped with two encoders to accurately monitor the wrist flexion / extension, ulnar / radial deviation, and forearm internal / external rotation angles during rehabilitation training. The encoders are installed in two locations: the tail end of the circumferential DC motor (7) and the bottom of the horizontal joint motor (29). Both encoders are directly integrated with the motor to form a complete unit, which is used to directly monitor the real-time rotation angle of the motor and provide feedback on the actual training situation of the patient's wrist during rehabilitation training.

6. The underactuated three-degree-of-freedom wrist rehabilitation robot according to claim 1, characterized in that: The wrist rehabilitation robot is equipped with two torque sensors to monitor the force on the wrist joint during the rehabilitation training process in real time. The torque sensors are integrated at the tail end of the circumferential DC motor (7) and the bottom of the horizontal joint motor (29). The torque sensor at the tail end of the circumferential DC motor (7) monitors the torque on the patient's forearm internal / external rotation movements, while the torque sensor at the bottom of the horizontal joint motor (29) monitors the torque on the patient's wrist ulnar / radial deviation and wrist flexion / extension rehabilitation movements.

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