A planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid actuation and its application

Abstract

This invention discloses a planar arbitrary trajectory motion lower limb rehabilitation robot and its application based on a rigid-flexible hybrid drive. The rehabilitation robot includes an adjustable frame, a linear-rotational two-degree-of-freedom motion arm, a lower limb support module, a cable drive module, and a lower limb fixation module. The leveling and lifting of the adjustable frame are achieved through adjustable casters and a lifting column. The linear and rotational motion of the linear-rotational two-degree-of-freedom motion arm are achieved through a linear module and joint motors. The lower limb support module provides fixation and support for the feet and lower legs and coordinates with foot movements. The cable drive module assists in knee flexion movements by changing the cable tension. This invention can achieve the cascading of linear and rotational degrees of freedom according to the user's vital signs and desired movement patterns, changing the current situation of single motion trajectories. Through flexible control, it enables active training, allowing the lower limbs to have more movement modes, customizing training trajectories, and improving the targeting of rehabilitation training.

Description

Technical Field

[0001] This invention belongs to the field of medical rehabilitation robots, specifically relating to a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive and its application. Background Technology

[0002] Studies have shown that scientifically planned repetitive exercises can gradually improve muscle strength and coordination in patients with limb motor impairments. Furthermore, the nervous system has a degree of remodeling potential; after exercise rehabilitation training, the relationship between limb movement and brain nerves can be rebuilt to some extent. Continuous stimulation of damaged nerves and muscles gradually restores the patient's ability to coordinate and control their limbs. Moreover, paralyzed patients and those in prolonged comas require some exercise to prevent complications such as muscle atrophy and joint stiffness. Therefore, many experts and scholars have designed and researched a variety of limb rehabilitation equipment to assist patients in performing repetitive movements.

[0003] Current lower limb rehabilitation equipment suffers from the following shortcomings: Most equipment focuses solely on assisted walking training, targeting patients with some degree of autonomy who require walking assistance, neglecting the movement needs of paralyzed or unconscious patients. A small number of supine rehabilitation devices only allow for fixed-track movement training, which lacks specificity and may lead to boredom or aversion after prolonged use. Secondly, some lower limb rehabilitation equipment has fixed structural parameters, particularly the inability to adjust training tracks. Patients of different body types experience varying degrees of discomfort with a single device, limiting its applicability and hindering its widespread use and promotion. Finally, isolated, multi-degree-of-freedom rigid movements can lead to complex movements, poor comfort, and certain risks. Generally, rope-driven systems are not only limited in location but also numerous, potentially causing interference between the ropes and the patient. Therefore, it is necessary to develop and design a supine lower limb rehabilitation device with a hybrid rigid-flexible drive system capable of providing multiple training tracks. Summary of the Invention

[0004] The purpose of this invention is to provide a planar arbitrary trajectory motion lower limb rehabilitation robot and its application based on a rigid-flexible hybrid drive, which adjusts the exercise training strategy according to the patient's body shape, thereby performing more stable, comfortable and diverse training movements.

[0005] A planar arbitrary trajectory motion lower limb rehabilitation robot based on rigid-flexible hybrid drive includes an adjustable frame, a lower limb fixation module, a rope drive module, a linear-rotation two-degree-of-freedom motion arm, and a lower limb support module.

[0006] The adjustable frame includes adjustable casters, frame chassis, lifting column, foot pedal connecting plate and lifting column connecting seat. The adjustable casters are fixed to the four corners of the frame chassis, the lifting column is fixed to the crossbeam of the frame chassis, and the two symmetrical foot pedal connecting plates (104) are fixed to the top of the lifting column through the lifting column connecting seat.

[0007] The rope drive module includes two rope drive motor frames, which are symmetrically mounted on the foot pedal connection plate.

[0008] The linear-rotational two-degree-of-freedom motion arm realizes the main planar rigid motion and consists of two symmetrical sets of structures, symmetrically mounted on two foot pedal connecting plates. Each set of structures is symmetrically mounted with a lower limb support module. Each lower limb support module is rotatably mounted with a lower limb fixation module. Each lower limb fixation module is connected to a rope drive module on the same side via a rope.

[0009] Furthermore, two sets of linear-rotational two-degree-of-freedom motion arms are provided for the lower limbs of the human body and are installed symmetrically. Each set of linear-rotational two-degree-of-freedom motion arms includes a linear module, a joint motor, a joint seat, and a rotating arm. The slider on the linear module moves through the operation of the servo motor to achieve translational degree of freedom. The joint seat is fixed to the slider of the linear module. The outer ring of the joint motor is fixed to the joint seat. Finally, the rotating arm is connected to the end of the harmonic reducer of the joint motor to realize the rotational movement of the rotating arm, so that the end of the rotating arm can move along any trajectory in the motion space. The two rotating arms are symmetrically retracted at the end to minimize the distance between them, thereby reducing the abduction angle of the legs during human movement.

[0010] Furthermore, the lower limb fixation module includes a rope traction leg support and a foot fixation device; the foot fixation device fixes the user's foot, the rope traction leg support is fixed to the lower leg near the knee, and the rope traction leg support is provided with a rope traction ring.

[0011] Furthermore, the rope drive module also includes a rope drive motor, a rope drive reducer, and a drive rope pulley; the rope drive motor frame is in the shape of a "7", including a horizontal barrel and a diagonal bar, and the horizontal barrel sections of two rope drive motor frames are connected together; each rope drive motor frame horizontal barrel is equipped with a rope drive reducer and a rope drive motor connected to the rope drive reducer; the drive rope pulley is located on the outside of the horizontal barrel of the rope drive motor frame and is fixed on the output shaft of the rope drive reducer and rotates with it, the rope is wound on the drive rope pulley, and the other end of the rope passes through the rope traction ring set on the rope traction leg support.

[0012] Furthermore, the lower limb support module includes two symmetrical sets of traction leg support fixing frames, a first connecting arm, a second connecting arm, and a foot pedal connecting plate; the traction leg support fixing frame is fixed together with the rope traction leg support and fixed on the connecting shaft of the first connecting arm, and the two parts can rotate relative to each other; the connecting shaft of the first connecting arm is connected to the end of the rotating arm and can rotate relative to each other; the second shaft of the first connecting arm is connected to the first axis of the second connecting arm, the second shaft of the second connecting arm is connected to the rotating shaft of the foot pedal connecting plate, and the buckle groove of the foot pedal connecting plate is connected to the buckle of the foot fixing device; the axes of the lower limb support module are at an angle to each other, so as to ensure the ankle joint position and allow the human body posture to be naturally relaxed, adapting to the posture changes of the human body during the robot's movement and ensuring movement comfort.

[0013] An application of a planar arbitrary trajectory motion lower limb rehabilitation robot based on rigid-flexible hybrid drive includes the following: A physician inputs a rehabilitation prescription into the robot. The physician adjusts the height of the adjustable frame's lifting column to match the bed, patient, and initial position. The patient's feet are fixed to the base plate of the lower limb fixation module and secured by a foot fixation device, thus fixing the ankle to the robot. The leg is fixed to a rope traction leg support, which wraps around the lower leg and is connected to the rope. The robot performs rehabilitation exercises in three working modes.

[0014] Guided rehabilitation mode: The doctor inputs the exercise rehabilitation prescription into the robot and connects the patient's lower limbs to the robot. The patient does not need to control the movement or actively exert force. The robot guides the patient's lower limbs to execute the rehabilitation prescription in the pre-set way, while ensuring that the output force, speed and position are within the human body's comfort range, avoiding traction and compression of the limbs, and driving the movement of the lower limbs.

[0015] Follow-up rehabilitation mode: The doctor inputs the personalized exercise rehabilitation prescription into the robot and connects the patient's lower limbs to the robot. The patient needs to have an active intention to move and try to control the limbs to move according to the rehabilitation prescription. In this mode, the robot assists and restrains the patient's limbs through a flexible control strategy. Force and position feedback can quickly identify the human body's movement intention and follow the human body to assist in movement, ensuring rehabilitation effect and patient comfort, and realizing the active-passive rehabilitation mode of human body active robot passive movement.

[0016] Resistance-based rehabilitation mode: The physician inputs the exercise rehabilitation prescription into the device, connects the patient's lower limbs to the device, and applies resistance to the patient during the movement along a predetermined trajectory. Force and position feedback are used to achieve weight-bearing training for the human body. By applying resistance to the patient during the movement along the predetermined trajectory, the patient resists the body in a predetermined path, training the lower limb coordination and muscle strength, and achieving further rehabilitation effects.

[0017] Furthermore, the robot acquires the output thrust and joint torque of the linear guide in real time during operation, calculates the end-effector output force, installs a force sensor at the end, and adjusts the movement of the human and equipment in a timely manner through different preset operating strategies.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The present invention provides a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive, wherein the lower limb bearing module passively adapts to the foot posture by rotating through the first connecting arm, the second connecting arm, and the foot pedal connecting plate, so that the foot fixing device can maintain the most suitable relative posture for the patient, and is designed with rotation limit to prevent injury due to excessive rotation angle, which is beneficial to improving the stability of training movements and the comfort of patient use.

[0020] 2. The present invention provides a planar arbitrary trajectory motion lower limb rehabilitation robot based on rigid-flexible hybrid drive. By connecting the linear and rotational degrees of freedom through a linear-rotation two-degree-of-freedom motion arm, the current situation of single motion trajectory can be changed. Moreover, it can be actively trained through force control, so that the patient's lower limbs have more motion modes, and the training trajectory can be customized, thus improving the pertinence of lower limb rehabilitation training.

[0021] 3. The present invention provides a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive. The rope drive module can be combined with the rope traction leg support to assist movement. By adjusting the rope tension and coordinating with the movement of the foot fixation device, it provides assistance for movements such as knee flexion, avoiding injuries caused by the confrontation between the person and the equipment. Furthermore, the flexible rope drive can greatly reduce the complexity of the mechanism. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive according to the present invention.

[0023] Figure 2 This is a schematic diagram of the adjustable frame structure of the present invention;

[0024] Figure 3 This is a schematic diagram of the lower limb fixation module structure of the present invention;

[0025] Figure 4 This is a schematic diagram of the lower limb support module structure of the present invention;

[0026] Figure 5 This is a schematic diagram of the rope drive module structure of the present invention;

[0027] Figure 6 This is a schematic diagram of the linear-rotational two-degree-of-freedom motion arm structure of the present invention;

[0028] In the diagram: 001-Adjustable frame, 101-Adjustable casters, 102-Frame chassis, 103-Lifting column, 104-Foot pedal connecting plate, 105-Lifting column connecting seat, 002-Lower limb fixation module, 201-Rope traction leg support, 202-Foot fixing device, 003-Rope drive module, 301-Rope drive motor, 302-Rope drive reducer, 303-Rope drive motor frame, 304-Drive rope wheel, 004-Linear-rotary two-degree-of-freedom motion arm, 401-Linear module, 402-Joint motor, 403-Joint seat, 404-Rotating arm, 005-Lower limb bearing module, 501-Traction leg support fixing frame, 502-First connecting arm, 503-Second connecting arm, 504-Foot pedal connecting plate. Detailed Implementation

[0029] The present invention will now be further described with reference to the accompanying drawings.

[0030] This invention discloses a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on a rigid-flexible hybrid actuation system, such as... Figure 1 As shown, it includes an adjustable frame 001, a lower limb fixation module 002, a rope drive module 003, a linear-rotational two-degree-of-freedom motion arm 004, and a lower limb support module 005. The linear-rotational two-degree-of-freedom motion arm 004 achieves main planar rigid motion, allowing the end-effector trajectory to be any trajectory within the workspace. It is connected to the rope drive module to traction the leg support to assist in movements such as knee flexion. The lower limb fixation module 002, pulled by the rope drive module 003, drives the lower leg to cooperate in assisting movement. The lower limb support module 005 mainly bears the structural force, ensuring that the posture changes according to the preset parameters. The adjustable frame 001 enables the main body to be raised and lowered to adjust the position of the bed, the patient, and the initial position.

[0031] like Figure 2 As shown, the adjustable frame 001 includes four adjustable casters 101, a frame chassis 102, a lifting column 103, two linear module connecting plates 104, and a lifting column connecting seat 105. The adjustable casters 101 are installed at the four corners of the bottom surface of the frame chassis 102. The support height of the casters can be adjusted to ensure the frame is level and the equipment is stable. The lifting column 103 is fixed to the central crossbeam of the frame chassis 102. The working height of the equipment can be adjusted by raising and lowering the crossbeam to accommodate beds of different heights and adapt to individual patient differences. The lifting column connecting seat 105 is fixed to the end of the lifting column 103, and the two linear module connecting plates 104 are symmetrically fixed to the lifting column connecting seat 105.

[0032] like Figure 3As shown, two sets of lower limb fixation modules 002 are provided for the lower limbs of the human body; including a rope traction leg support 201 and a foot fixation device 202. The foot fixation device 202 fixes the user's feet, and the rope traction leg support 201 is fixed to the lower leg near the knee. A rope passes through the traction ring, and the rope drive module 003 applies tension to the rope to assist movement.

[0033] like Figure 4 As shown, the rope drive module 003 is provided with two sets corresponding to the lower limbs of the human body, including a rope drive motor 301, a rope drive reducer 302, a rope drive motor frame 303, and a drive rope wheel 304. The rope drive motor frame 303 is fixed on the linear module connecting plate 104 in a mirror symmetry, and the rope drive reducer 302 is connected to it. The rope drive motor 301 is fixed on the rope drive reducer 302 and drives the rope drive reducer 302 to rotate. The drive rope wheel 304 is fixed on the output shaft of the rope drive reducer 302 and rotates accordingly. The rope is wound around the drive rope wheel 304, and the other end is connected to the rope traction leg support 201.

[0034] like Figure 5 As shown, the linear-rotational two-degree-of-freedom motion arm 004 is configured with two sets corresponding to the human lower limb, including two symmetrical linear modules 401, joint motors 402, joint seats 403, and a rotating arm 404. The two symmetrical linear modules 401 are fixed to the left and right sides of the linear module connecting plate 104 in a horizontal installation manner. The slider of the linear module 401 is driven by the operation of the servo motor to achieve translational degree of freedom. The joint seat 403 is fixed to the slider of the linear module 401. The outer ring of the joint motor 402 is fixed to the joint seat 403. Finally, the rotating arm 404 is connected to the end of the harmonic reducer of the joint motor 402 to realize the rotational movement of the rotating arm 404. The overall design allows the end of the rotating arm 404 to achieve arbitrary trajectory movement within the motion space.

[0035] like Figure 6As shown, the lower limb support module 005 is provided with two sets corresponding to the human lower limb, including two symmetrical sets of traction leg support fixing frames 501, a first connecting arm 502, a second connecting arm 503, and a foot pedal connecting plate 504. The traction leg support fixing frame 501 is fixed together with the rope traction leg support 201 to restrict knee joint abduction, and is fixed on the connecting shaft of the first connecting arm 502 to bear the overall force. The two parts can rotate relative to each other. The connecting shaft of the first connecting arm 502 is connected to the end of the rotating arm 404 and can rotate relative to each other. The second shaft of the first connecting arm 502 is connected to the first axis of the second connecting arm 503. The second shaft of the second connecting arm 503 is connected to the rotating shaft of the foot pedal connecting plate 504. The buckle groove of the foot pedal connecting plate 504 can be connected to the buckle of the foot fixing device 202. The axes of the two ends of the first connecting arm 502 are at a certain angle, and a rotation limit is designed between the two connecting arms. The axes of the two ends of the second connecting arm 503 are also at a certain angle. The foot pedal connecting plate 504 can move smoothly within the limit through three rotating axes with different angles.

[0036] This invention discloses a planar arbitrary trajectory recumbent lower limb rehabilitation robot based on a rigid-flexible hybrid drive. Its primary target users are patients with lower limb motor disorders such as stroke and spinal cord injury, placing certain demands on ergonomics and user psychology. Guided by user psychology theory, the overall configuration adopts a leg-to-leg movement configuration, abandoning side-symmetry design to reduce visual volume, optimize the wearing and use process, and reduce user psychological stress. Guided by ergonomic and sports rehabilitation theories, the overall structure is narrowed to minimize the distance between the two feet. The main structural improvements based on this theory include the rotating arm 404, which minimizes the distance from its end to the center plane without interference. The linear module connecting plates 104 are symmetrically arranged, fixing the two plates together to reduce structural thickness while ensuring strength. Furthermore, the design fully considers the lower limb degrees of freedom; the lower limb support module 005 is designed with compliance, ensuring the limbs maintain a natural posture during movement, improving patient experience, ensuring rehabilitation effectiveness and patient comfort, and achieving the desired rehabilitation results.

[0037] The main initial working states of a planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive according to the present invention are as follows: Figure 1The patient lies supine facing the device, with lower limb fixation modules 002 fitted on both legs. The feet are secured by foot fixation devices 202, and the lower legs are secured by rope traction leg supports 201. After the entire supine rehabilitation robot returns to its initial position, the entire lower limb support module 005, along with the lower limb fixation module 002, is fixed to the end of the rotating arm 404. Each component rotates independently, ensuring that the ankle can move along a predetermined trajectory. The traction leg support fixation frame 501 prevents knee abduction, ensuring the safety of movement. The main form of movement is supine rehabilitation, with the lower limb support module 005 moving along a predetermined trajectory in a plane driven by the linear-rotational two-degree-of-freedom motion arm 004. The rope drive module 003 assists in the safe and efficient completion of the overall function by flexing and extending the knee joint. The robot can acquire the output thrust and joint torque of the linear guide in real time during operation, calculate the end-effector output force, and optionally install a force sensor at the end. It can adjust the movement of the human body and the equipment in a timely manner through different preset operating strategies. The robot can provide patients with a variety of movement modes: passive rehabilitation mode, in which the limb movement is completely guided and driven by the equipment; active rehabilitation mode, in which the robot actively assists the movement of the lower limbs, and the patient can gain a certain degree of control, which is conducive to the patient's further exercise rehabilitation training.

[0038] Guided rehabilitation mode: The physician inputs the personalized exercise rehabilitation prescription into the device and connects the patient's lower limbs to the device. The patient does not need to control the movement or actively exert force. The device guides the patient's lower limbs to execute the rehabilitation prescription in the pre-set manner, while ensuring that the output force, speed and position are within the human body's comfort range, avoiding traction and compression of the limbs, and can also promote lower limb movement.

[0039] Follow-up rehabilitation mode: The physician inputs the personalized exercise rehabilitation prescription into the device and connects the patient's lower limbs to the device. The patient needs to have an active intention to move and try to control the limbs to move according to the rehabilitation prescription. In this mode, the device assists and restrains the patient's limbs through a flexible control strategy. Force and position feedback can quickly identify the human body's movement intention and follow the human body's assisted movement to ensure rehabilitation effect and patient comfort, realizing an active-passive rehabilitation mode of human body active movement and device passive movement.

[0040] Resistance-based rehabilitation mode: force and position feedback can enable weight-bearing training of the human body. By applying resistance to the patient during movement along a predetermined trajectory, the patient resists the movement of the human body in a predetermined trajectory, thereby training the lower limb coordination and muscle strength and achieving further rehabilitation effects.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid actuation, characterized in that: It includes an adjustable frame (001), a lower limb fixation module (002), a rope drive module (003), a linear-rotation two-degree-of-freedom motion arm (004), and a lower limb support module (005); The adjustable frame (001) includes adjustable casters (101), frame chassis (102), lifting column (103), foot pedal connecting plate (104), and lifting column connecting seat (105). The adjustable casters (101) are fixed to the four corners of the frame chassis (102), the lifting column (103) is fixed to the crossbeam of the frame chassis (102), and the foot pedal connecting plate (104) is arranged symmetrically and fixed to the top of the lifting column (103) through the lifting column connecting seat (105). The rope drive module (003) includes two rope drive motor frames (303), which are symmetrically mounted on the foot pedal connecting plate (104); The linear-rotational two-degree-of-freedom motion arm (004) realizes the main planar rigid motion. It consists of two symmetrical sets of structures, symmetrically installed on two foot pedal connecting plates (104). Each set of structures is symmetrically installed with a lower limb bearing module (005). Each lower limb bearing module (005) is rotatably equipped with a lower limb fixing module (002). Each lower limb fixing module (002) is connected to the rope drive module (003) on the same side through a rope. The linear-rotational two-degree-of-freedom motion arm (004) is provided in two sets corresponding to the lower limbs of the human body and is installed symmetrically. Each set of linear-rotational two-degree-of-freedom motion arm (004) includes a linear module (401), a joint motor (402), a joint seat (403), and a rotating arm (404). The slider on the linear module (401) moves through the operation of the servo motor to realize translational degree of freedom. The joint seat (403) is fixed on the slider of the linear module (401). The outer ring of the joint motor (402) is fixed to the joint seat (403). Finally, the rotating arm (404) is connected to the end of the harmonic reducer of the joint motor (402) to realize the rotational movement of the rotating arm (404), so that the end of the rotating arm (402) can move along any trajectory in the motion space. The two rotating arms (402) are symmetrically inwardly designed at the end to minimize the distance between them, thereby reducing the abduction angle of the legs during human movement.

2. The planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive according to claim 1, characterized in that: The lower limb fixation module (002) includes a rope traction leg support (201) and a foot fixation device (202); the foot fixation device (202) fixes the user's foot, and the rope traction leg support (201) is fixed to the lower leg near the knee. The rope traction leg support (201) is provided with a rope traction ring.

3. The planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive according to claim 2, characterized in that: The rope drive module (003) also includes a rope drive motor (301), a rope drive reducer (302), and a drive rope wheel (304); the rope drive motor frame (303) is "7" shaped, including a horizontal barrel and a diagonal bar, and the horizontal barrel parts of the two rope drive motor frames (303) are connected together; the rope drive reducer (302) and the rope drive motor (301) connected to the rope drive reducer (302) are installed inside the horizontal barrel of the rope drive motor frame (303); the drive rope wheel (304) is located on the outside of the horizontal barrel of the rope drive motor frame (303), and is fixed on the output shaft of the rope drive reducer (302) and rotates with it, the rope is wound on the drive rope wheel (304), and the other end of the rope passes through the rope traction ring set on the rope traction leg support (201).

4. The planar arbitrary trajectory motion recumbent lower limb rehabilitation robot based on rigid-flexible hybrid drive according to claim 2, characterized in that: The lower limb support module (005) includes two symmetrical sets of traction leg support fixing frames (501), a first connecting arm (502), a second connecting arm (503), and a foot pedal connecting plate (504). The traction leg support fixing frame (501) is fixed together with the rope traction leg support (201) and fixed on the connecting shaft of the first connecting arm (502). The two parts can rotate relative to each other. The connecting shaft of the first connecting arm (502) is connected to the end of the rotating arm (404) and can rotate relative to each other. The second shaft of the first connecting arm (502) is connected to the first axis of the second connecting arm (503), and the second shaft of the second connecting arm (503) is connected to the rotating shaft of the foot pedal connecting plate (504). The buckle groove of the foot pedal connecting plate (504) is connected to the buckle of the foot fixing device (202). The axes of the lower limb support module (005) are at an angle to each other, so as to ensure the ankle joint position and allow the human body posture to be naturally relaxed. In the robot movement, it adapts to the posture changes of the human body during the movement process and ensures the comfort of movement.

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