A control method for eight-bar mechanism for medical lower limb rehabilitation

Abstract

The present invention provides an eight-bar mechanism for medical lower limb rehabilitation, wherein the eight-bar mechanism is composed of a plurality of cranks connected in pairs to form an eight-bar mechanism model for the legs, and the eight-bar mechanism model for the legs is used to model the motion trajectory of the human leg and optimize it, and the method for optimizing the trajectory comprises the following steps: a patient sits on a chair, the eight-bar mechanism is installed on the side of the chair, a fulcrum device that can be fixed to the patient's foot is arranged at the bottom of the eight-bar mechanism, the tracking error algorithm does not include input angle variables, the number of optimization parameters is simplified, and the optimization efficiency is improved, the constraints only include rod length constraints and variable range conditions, and the limitations of the order constraints of the traditional algorithm are eliminated, and the order errors are avoided at the same time, and the tracking error based on the algorithm is used as the objective function, which has fewer optimization variables and simpler constraints, and is therefore more likely to obtain a satisfactory global optimal solution through the optimization algorithm.

Description

Technical Field

[0001] The present invention relates to the technical field of multiple medical devices, and in particular to a control method of an eight-bar mechanism for medical lower limb rehabilitation. Background Art

[0002] Medical lower limb rehabilitation institutions interact with the patient's lower limbs, simulate the movement trajectory of the patient's legs, use advanced mechanical and electronic equipment to assist the patient in lower limb movement, provide targeted rehabilitation training, help restore motor function, improve muscle strength and coordination, and promote the patient's recovery process. There are many problems with today's medical lower limb rehabilitation institutions:

[0003] (1) Structural complexity is a significant problem in medical lower limb rehabilitation institutions. Since lower limb rehabilitation involves the coordinated action of multiple joints and muscle groups, rehabilitation institutions often need to design multiple interrelated components to achieve complex movement patterns. This complexity not only increases the difficulty of manufacturing and assembly, but also increases costs, and may reduce the reliability and durability of the mechanism.

[0004] (2) Difficulty in processing and manufacturing is another issue that needs attention. Medical lower limb rehabilitation devices usually contain precise mechanical parts and complex motion systems, which place high demands on processing technology and manufacturing accuracy. However, due to the limitations of current processing technology and equipment, it is sometimes difficult to manufacture these high-precision parts, thus affecting the overall performance and treatment effect of the rehabilitation device.

[0005] (3) The inability to achieve multiple forms of movement transformation is also a shortcoming of medical lower limb rehabilitation institutions. In the actual rehabilitation process, patients may need to undergo a variety of different exercise training to promote the recovery of lower limb function. However, due to the limitations of the design of rehabilitation institutions, it is sometimes difficult to achieve these diverse movement patterns, which limits the flexibility and effectiveness of rehabilitation treatment.

[0006] (4) The lack of rich trajectory shapes is also a problem in medical lower limb rehabilitation institutions. The movement trajectory of the rehabilitation institution directly affects the patient's movement pattern and rehabilitation effect. However, due to design limitations, the trajectory shapes of existing rehabilitation institutions are often relatively simple and cannot meet the personalized needs of different patients. This may lead to the rehabilitation process being inaccurate and inefficient, affecting the patient's rehabilitation progress.

[0007] Limited personalized rehabilitation: Each patient's lower limb movement trajectory is unique and is affected by multiple factors such as injury type, severity, and personal physique. Since lower limb rehabilitation institutions cannot meet the unique trajectory needs of each patient, it is difficult to provide a highly personalized rehabilitation program for each patient. This may lead to poor rehabilitation results and may even prolong the rehabilitation period. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a control method for a medical lower limb rehabilitation eight-bar mechanism to solve the problems raised in the above background technology. The planar eight-bar mechanism can realize complex motion transformation, which enables it to simulate the lower limb motion trajectory that is closer to the real walking state. It has a rich motion trajectory shape, which means that it can adjust and optimize the motion trajectory according to the patient's specific situation and rehabilitation goals. By adjusting the length of the rod, the connection method and the motion parameters, the planar eight-bar mechanism can generate different trajectory curves to meet the personalized needs of different patients.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solutions: a control method of an eight-bar mechanism for medical lower limb rehabilitation, wherein the eight-bar mechanism is composed of a plurality of cranks connected in pairs to form an eight-bar mechanism model for the leg, and the eight-bar mechanism model for the leg is used to optimize the motion trajectory of the human leg, and the method for optimizing the trajectory comprises the following steps:

[0010] S1. The patient sits on a chair, and the eight-bar mechanism is installed on the side of the chair. A fulcrum device that can be fixed to the patient's foot is set at the bottom of the eight-bar mechanism. A fulcrum at the top of the eight-bar mechanism is used as a rotation point, and the rotation point is connected to the motor;

[0011] S2. According to the patient's leg length and rehabilitation requirements, a personalized rehabilitation motion trajectory is formulated. A point in the output trajectory of the linkage mechanism is selected as the optimal starting point of the trajectory output through the starting point optimization algorithm, and then matched with the target point sequence to segment the curve;

[0012] S3, then determine the target point coordinates according to the desired motion trajectory, optimize and adjust the length of each rod, and adjust the length, connection method and motion parameters of the rods. The tracking error of the objective function is calculated using the curve point sequence matching algorithm to adjust and optimize the motion trajectory;

[0013] S4. Fix the patient's feet on the fulcrum device and start the motor. At this time, the patient's legs will move together with the fulcrum device, thereby achieving the purpose of lower limb rehabilitation.

[0014] Furthermore, in the starting point optimization algorithm in step S2, each point in the long point sequence is first used as a starting point, and then the matching degree of the curve segments after they are used as starting points is compared, so as to find the optimal starting point.

[0015] Furthermore, any point in the trajectory output point is selected as the starting point. After the curve segmentation algorithm, the path position coordinates corresponding to the target point sequence and the trajectory output point sequence are obtained, a new cumulative distance is constructed, and the specific sequence point of the best starting point is obtained.

[0016] Furthermore, in step S1, the fulcrum device for fixing the patient's foot is set as the trajectory point P, and the motion trajectory of the trajectory point P is used to simulate the motion trajectory of the human foot.

[0017] Furthermore, in step S1, the point for connecting the motor is set as trajectory point A, and the point connected to the motor through the crank is set as trajectory point B. The crank AB rotates around point A, and the rotation of the crank AB drives point P to move.

[0018] Furthermore, the path position coordinates corresponding to the target point sequence and the trajectory output point sequence are: Among them, k represents the kth point in the long point sequence as the starting point, constructing a new cumulative distance, F: To solve the minimum value of F, the formula can be expressed as: F min =min[F1,F2,…,F k ,…,F n ], and get the k value when F is the smallest. Then the kth point in the long point sequence is the best starting point, and the closed curve can be reasonably segmented.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention overcomes the defects of the complex structure of the medical lower limb rehabilitation mechanism and is easy to manufacture and install. In the medical lower limb rehabilitation mechanism, it helps to quickly deploy and adjust the equipment to meet the personalized needs of different patients. The simple structure also reduces the manufacturing cost, making this rehabilitation mechanism more economical and easier to popularize to more medical institutions and families. The simple structure helps to improve the reliability and stability of the equipment and is easy to maintain and repair.

[0021] 2. The present invention can realize complex motion transformation, which enables it to simulate the lower limb motion trajectory that is closer to the real walking state. It has a rich motion trajectory shape and can adjust and optimize the motion trajectory according to the patient's specific situation and rehabilitation goals. By adjusting the length of the rod, the connection method and the motion parameters, the planar eight-bar mechanism can generate different trajectory curves to meet the personalized needs of different patients.

[0022] 3. The present invention simplifies the number of optimization parameters and improves optimization efficiency by not including input angle variables in the tracking error algorithm. The constraints only include rod length constraints and variable range conditions, which gets rid of the limitations of sequential constraints of traditional algorithms and avoids sequence errors. The tracking error based on the algorithm is used as the objective function, which has fewer optimization variables and simpler constraints. Therefore, it is more likely to obtain a satisfactory global optimal solution through the optimization algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of a leg eight-bar mechanism model of a control method of an eight-bar mechanism for medical lower limb rehabilitation according to the present invention;

[0024] Figure 2 A schematic diagram of the motion trajectory of a control method of an eight-bar mechanism for medical lower limb rehabilitation according to the present invention;

[0025] Figure 3 This is an effect diagram after the curve points of the control method of the medical lower limb rehabilitation eight-bar mechanism of the present invention are matched;

[0026] Figure 4 It is a schematic diagram of the closed-loop matching result of a control method of a medical lower limb rehabilitation eight-bar mechanism according to the present invention after a starting point optimization algorithm is applied;

[0027] Figure 5 This is a diagram showing the optimization effect of a control method for an eight-bar mechanism for medical lower limb rehabilitation according to the present invention. DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0029] See also Figures 1 to 5 The present invention provides a technical solution: a control method for an eight-bar mechanism for medical lower limb rehabilitation, wherein the eight-bar mechanism is composed of a plurality of cranks connected in pairs to form an eight-bar mechanism model for the leg, and the eight-bar mechanism model for the leg is used to optimize the motion trajectory of the human leg. The method for optimizing the trajectory includes the following steps:

[0030] S1. The patient sits on a chair, and the eight-bar mechanism is installed on the side of the chair. A fulcrum device that can be fixed to the patient's foot is set at the bottom of the eight-bar mechanism. A fulcrum at the top of the eight-bar mechanism is used as a rotation point, and the rotation point is connected to the motor;

[0031] S2. According to the patient's leg length and rehabilitation requirements, a personalized rehabilitation motion trajectory is formulated. A point in the output trajectory of the linkage mechanism is selected as the optimal starting point of the trajectory output through the starting point optimization algorithm, and then matched with the target point sequence to segment the curve;

[0032] S3, then determine the target point coordinates according to the desired motion trajectory, optimize and adjust the length of each rod, and adjust the length, connection method and motion parameters of the rods. The tracking error of the objective function is calculated using the curve point sequence matching algorithm to adjust and optimize the motion trajectory;

[0033] S4. Fix the patient's feet on the fulcrum device and start the motor. At this time, the patient's legs will move together with the fulcrum device, thereby achieving the purpose of lower limb rehabilitation.

[0034] In this embodiment, in step S1, the fulcrum device for fixing the patient's foot is set as the trajectory point P, and the motion trajectory of the human foot is simulated by the motion trajectory of the trajectory point P. In step S1, the point for connecting the motor is set as the trajectory point A, and the point connected to the motor through the crank is set as the trajectory point B. The crank AB rotates around the point A, and the rotation of the crank AB drives the point P to move;

[0035] Geometric parameters of the planar eight-bar mechanism:

[0036] A and D are fixed racks, θ i Indicates the rod L i The angle with the x-axis. Among them, θ0=0, θ7=θ3+α1, θ 10 =θ9-α2-π,α1

[0037] represents the angle between L3 and L7, α2 represents the angle between L9 and L 10 Angle.

[0038] The coordinates of the trajectory point P can be expressed as:

[0039]

[0040] Then, the target point coordinates are determined according to the expected motion trajectory, and the lengths of each rod are optimized and adjusted. The tracking error of the objective function is calculated using the curve point sequence matching algorithm. The specific method is as follows:

[0041] The target point sequence is expressed as follows:

[0042] D l ={d1,d2,...d i ,...d m}, Where m represents the number of target points. The output trajectory of the mechanism is uniformly sampled and discretized into a large number of points. The trajectory points are expressed as follows:

[0043] P l ={p1,p2,…p j ,...p n}, Where n represents the number of trajectory points and constructs a distance matrix E to represent the point sequence D l and P l The distance between every two points in :

[0044]

[0045] Then, construct a matrix S to store the coordinate values ​​of the elements in matrix E:

[0046] S=[s1,s2,…,s j …,sn ], The elements in S must meet the restrictions, including:

[0047] or

[0048] The elements in S represent the coordinates of the elements in E. By adding the elements in E corresponding to these coordinates, we can get a cumulative distance C. It can be expressed by the following formula:

[0049]

[0050] Represents the cumulative distance under the condition of the t-th S matrix.

[0051] Finally, find the minimum value of C:

[0052] C min =min[C1,C2,…,C t ,…]

[0053] In this embodiment, the starting point optimization algorithm in step S2 first takes each point in the long point sequence as a starting point, and then compares the matching degree of the curve segments after they are taken as starting points, so as to find the optimal starting point;

[0054] Select any point in the trajectory output point as the starting point, and after the curve segmentation algorithm, obtain the path position coordinates corresponding to the target point sequence and the trajectory output point sequence, construct a new cumulative distance, and find the specific sequence point of the best starting point;

[0055] First, select any point in the trajectory output point as the starting point. After the curve segmentation algorithm, the path position coordinates corresponding to the target point sequence and the trajectory output point sequence are obtained as follows:

[0056]

[0057] Among them, k represents the kth point in the long point sequence as the starting point. Then, construct a new cumulative distance F:

[0058] Finally, to find the minimum value of F, the formula can be expressed as: F min =min[F1,F2,…,F k ,…,F n ]

[0059] At this time, the k value when F is the smallest is obtained, then the kth point in the long point sequence is the best starting point, and the closed curve can be reasonably segmented.

[0060] The specific process of rod length optimization is as follows:

[0061] Select the target point of the desired trajectory:

[0062] Six target points:

[0063]

[0064] Eight target points:

[0065]

[0066] Then the tracking error is calculated using curve point sequence matching and substituted into the intelligent optimization algorithm for optimization.

[0067] In actual operation, the patient sits on a chair and the eight-bar mechanism is installed on the side of the chair. A motor is connected to point A to rotate the AB rod around point A. There is a device for fixing the patient's foot at point P. According to the patient's leg length and rehabilitation requirements, a personalized rehabilitation motion trajectory is formulated. Then the target point of the motion trajectory is determined, and the curve point sequence matching algorithm is used to optimize the design of each rod length. After the rod length is designed, the patient's foot is fixed at point P and the motor is started. At this time, the patient's leg will move with point P, thereby achieving the purpose of lower limb rehabilitation.

[0068] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

[0069] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A control method for an eight-bar mechanism for medical lower limb rehabilitation, characterized in that: The eight-bar mechanism is composed of a plurality of cranks connected in pairs to form a leg eight-bar mechanism model. The leg eight-bar mechanism model simulates the motion trajectory of the human leg and optimizes it. The optimization steps are as follows: S1. The patient sits on a chair, and the eight-bar mechanism is installed on the side of the chair. A fulcrum device that can be fixed to the patient's foot is set at the bottom of the eight-bar mechanism. A fulcrum at the top of the eight-bar mechanism is used as a rotation point, and the rotation point is connected to the motor; S2. According to the patient's leg length and rehabilitation requirements, a personalized rehabilitation motion trajectory is formulated. A point in the output trajectory of the linkage mechanism is selected as the optimal starting point of the trajectory output through the starting point optimization algorithm, and then matched with the target point sequence to segment the curve; S3, then determine the target point coordinates according to the desired motion trajectory, optimize and adjust the lengths of each rod, and adjust and optimize the motion trajectory by adjusting the connection mode and motion parameters, and using the curve point sequence matching algorithm to calculate the tracking error of the objective function; S4, fix the patient's foot on the fulcrum device and start the motor, then the patient's leg will move along with the fulcrum device, thereby achieving the purpose of lower limb rehabilitation; In step S2, the starting point optimization algorithm first takes each point in the long point sequence as the starting point, and then compares the matching degree of the curve segmentation after they are used as the starting point, so as to find the best starting point, and selects any point in the trajectory output point as the starting point. After the curve segmentation algorithm, the path position coordinates corresponding to the target point sequence and the trajectory output point sequence are obtained, a new cumulative distance is constructed, and the specific sequence point of the best starting point is obtained; The path position coordinates corresponding to the target point sequence and the trajectory output point sequence are: Among them, k represents the kth point in the long point sequence as the starting point, constructing a new cumulative distance, F: To solve the minimum value of F, the formula can be expressed as: F min =min[F1,F2,…,F k ,…,F n ], and get the k value when F is the smallest. Then the kth point in the long point sequence is the best starting point, and the closed curve can be reasonably segmented.

2. The control method of the eight-bar mechanism for medical lower limb rehabilitation according to claim 1, characterized in that: In step S1, the fulcrum device for fixing the patient's foot is set as a trajectory point P, and the motion trajectory of the trajectory point P is used to simulate the motion trajectory of the human foot.

3. The control method of the eight-bar mechanism for medical lower limb rehabilitation according to claim 1, characterized in that: In step S1, the point for connecting the motor is set as track point A, and the point connected to the motor through the crank is set as track point B. The crank AB rotates around point A, and the rotation of the crank AB drives point P to move.

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