阅读说明：本技术 一种基于张拉整体结构的仿生膝关节结构及控制方法设计 (Bionic knee joint structure based on tension integral structure and control method design ) 是由 孙中波 赵立铭 刘克平 王刚 段晓琴 易江 衡焘韬 于 2021-07-05 设计创作，主要内容包括：本发明公开了一种基于张拉整体结构的仿生膝关节结构及控制方法设计。针对人体膝关节的康复问题,基于仿生学原理,结合张拉整体结构刚柔耦合特性设计一种基于张拉整体结构的仿生膝关节结构。设计抗噪型归零神经网络模型作为控制方法。在仿生膝关节结构建立过程中考虑以下几点：a.根据人体膝关节肌肉、韧带、骨骼等组织承担的功能不同,将具有相同功能的组织简化为绳、杆结构,从而实现对人体膝关节的简化；b.分析仿生膝关节结构的运动学特性,并建立动力学模型；c.考虑膝关节伸直时的限位功能,通过连杆结构实现在外力作用下仿生膝关节结构的限位功能；d.在动力学模型中考虑人体膝关节力矩,体现膝关节运动对仿生膝关节结构的影响。(The invention discloses a bionic knee joint structure based on a tension integral structure and a control method design. Aiming at the rehabilitation problem of the knee joint of a human body, the bionic knee joint structure based on the integral tensioning structure is designed by combining the rigid-flexible coupling characteristic of the integral tensioning structure based on the bionics principle. And designing an anti-noise return-to-zero neural network model as a control method. The following points are considered in the process of establishing the bionic knee joint structure: a. according to different functions borne by tissues such as muscles, ligaments and bones of the knee joint of a human body, the tissues with the same functions are simplified into a rope and rod structure, so that the knee joint of the human body is simplified; b. analyzing the kinematics characteristics of the bionic knee joint structure and establishing a dynamics model; c. the limit function of the bionic knee joint structure under the action of external force is realized through the connecting rod structure in consideration of the limit function of the knee joint when the knee joint is straightened; d. the moment of the human knee joint is considered in the dynamic model, and the influence of the knee joint motion on the bionic knee joint structure is reflected.)

1. A bionic knee joint structure based on a tension integral structure and a control method design are characterized by comprising the following characteristics:

1) based on the physiological characteristics and the motion characteristics of the human knee joint. The structure of bones, muscles, ligaments and the like which play the same function in the knee joint movement process is simplified into the same rope and rod structure, so that the aim of simplifying the knee joint structure of a human body is fulfilled, and the kinematics and dynamics analysis of the bionic knee joint structure is facilitated;

2) performing kinematic analysis on the bionic knee joint structure and establishing a dynamic model, and considering that a coefficient similar to a spring damping coefficient exists in an elastic region of knee joint muscle tissues in the relation between external load and deformation in the dynamic modeling, so that non-conservative force related to the spring damping coefficient is considered in the establishing process of the dynamic model;

3) in order to embody the bionic performance of the bionic knee joint structure, the bionic knee joint structure based on the tensioning overall structure related by the patent imitates the limit function of the human knee joint during straightening movement, namely, tissues such as ligaments near the patella and the patella can prevent the knee joint from being excessively straightened when moving, thereby preventing the injury to the human body. The limit function of the bionic knee joint structure under the action of external force is realized through the two-link mechanism;

4) when a bionic knee joint structure dynamic model is designed, factors of the bionic knee joint structure dynamic model, such as mechanical structure errors, mechanical vibration, friction among components, Noise of feedback signals, external static friction and the like, are considered, so that an anti-Noise return-to-zero Neural Network (NTZNN) model is designed to control the bionic knee joint structure based on a tensioning integral structure;

5) the human body knee joint moment tau with different sizes generated by the knee joint when the lower limbs of the human body are in different rehabilitation training stages is considered_R. Therefore, in the process of establishing a dynamic model, the moment tau of the knee joint of the human body is considered_RTherefore, the influence of the human knee joint in the motion of the bionic knee joint structure is reflected.

2. The design of the bionic knee joint structure based on the tensegrity structure and the control method is characterized in that in the kinematic analysis in the step 2, a kinematic and dynamic model of the bionic knee joint structure is analyzed;

s201: in the kinematic analysis of the bionic knee joint structure, the geometric structure, the singular configuration and the working interval of the bionic mechanism are analyzed;

s202: the bionic knee joint mainly comprises two groups of two-link mechanisms and four groups of ropes;

s203: for a general tensegrity structure, when the structure is in an abnormal configuration, the actual degree of freedom of the structure is changed, so that the whole structure is unstable. For the bionic knee joint structure mentioned in the patent, because the mechanism simulates the limiting function of the knee joint of a human body, under the action of external force perpendicular to an x axis, the upper boundary of a working interval of the mechanism after being limited by the limiting function can be regarded as a singular configuration of the bionic knee joint structure for straightening movement. Due to the existence of the limiting function, the bionic knee joint structure can not reach the actual singular configuration when being straightened, so that the injury to the human body is avoided.

S204: when designing a bionic knee joint, the range which can be reached when the mechanism works, namely the working range of the system, is considered to be an important ring in the kinematic analysis of the structure. After ADAMS software dynamics simulation is adopted, experimental results show that under the action of an external force perpendicular to an x axis applied to a balance position of the bionic knee joint structure, the balance position reaches the upper bound of a working interval under the action of the external force, namely the singular configuration of the bionic knee joint structure during extension movement.

3. The design of the bionic knee joint structure based on the tensegrity structure and the control method is characterized in that the step 3 is a limit function designed based on the bionic principle of the knee joint. Under the action of an external force with the direction vertical to the x axis, the first part of the two connecting rods rotates upwards around the rotating joint from the balance position until the first part of the two connecting rods is vertical to the x axis, and in this case, the first part of the two connecting rods cannot rotate continuously even under the action of the external force. Realize the limit function of human knee joint on bionics principle, prevent that bionical knee joint structure from straightening excessively in the motion process.

4. The design of the bionic knee joint structure based on the tensegrity structure and the control method is characterized in that in the step 4, an NTZNN model is designed to control the bionic knee joint structure. The experimental result shows that the experimental effect can still achieve the expected effect after factors such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like are added in the dynamic model.

5. The bionic knee joint structure based on the tensegrity structure and the control method thereofThe instrument is characterized in that in the step 5, human knee joint moments tau with different sizes generated by different rehabilitation stages of the lower limbs of the human body in the rehabilitation training process are considered_R. For example, in the passive rehabilitation stage, the lower limbs are hemiplegic due to diseases such as stroke and the like, the limbs do not move coordinately so that the lower limbs can not move according to the will of the patient, and the human body can generate the moment resisting the rehabilitation training track in the rehabilitation training process, so the moment tau of the knee joint of the human body is generated in the rehabilitation training process at the moment_RIs an antagonistic moment, and can be set with tau in the process of establishing a dynamic model_RIs negative. In addition, there is a complete passive rehabilitation phase, which corresponds to the basic loss of the nerve conduction function between the central nervous system and the skeletal muscles of the lower limbs of the patient, and can also be considered as a passive rehabilitation phase for patients who have undergone a lower limb joint operation or a total knee replacement operation, in which the moment τ of the human knee joint is present_RAre very small. Aiming at the condition that a patient can generate moment actively following a rehabilitation training track at the end stage of a rehabilitation training stage, the moment tau of the knee joint of the human body is generated at the moment_RPositive values can be assumed in the kinetic model. In conclusion, in the dynamic model building process, the human knee joint moment tau_RPlay an important role. Human knee joint moments should be reflected in the system dynamics modeling to represent the effect of human generated forces on the motion of the biomimetic knee joint structure. Because the human knee joint moment is basically consistent in different rehabilitation stages, the human knee joint moment tau can be considered in stages_R。

Technical Field

The invention relates to the field of a stretching integral structure, knee joint bionics and a bionic structure, and relates to a bionic knee joint structure based on the stretching integral structure and a control method design.

Background

The integral tensioning structure has the characteristics of shape adjustability, stress controllability, rope tensile property, structural lightweight property and the like, and plays an important role in the field of bionics. In the rehabilitation training process, the rehabilitation training activities of the lower limb joints of the human body, particularly the knee joints, become important due to symptoms of lower limb hemiplegia, limb movement incoordination and the like caused by stroke. The human knee joint is composed of many bones, muscles and ligaments, so the knee joint can be considered as a rigid-flexible coupling structure. Therefore, from a bionics perspective analysis, it is not possible to simply map the knee joint structure into a traditional rigid linkage structure. On the other hand, the bionic knee joint structure can be built by utilizing a tension integral structure with rigid-flexible coupling characteristics from the characteristics of strong coupling of knee joint muscles, ligaments and bones.

At present, based on gait characteristics of lower limb movement of a human body, a knee joint rehabilitation robot has been designed, adopts a rigid-flexible coupling structure, is used as a passive exoskeleton rehabilitation robot, and has the characteristics of light weight, working efficiency the same as that of an active exoskeleton rehabilitation robot and the like. In addition, based on the principle of bionics, two kinds of bionic structures based on ankle joints and knee joints have been developed. The physiological structures of the ankle joint and the knee joint of the human body are fully considered by the two bionic structures. In the structural design, the bones of the knee and ankle joints of the human body are regarded as rod structures for tensioning the integral structure, and the tissues such as muscles, ligaments and the like in the joint tissues are regarded as rope structures for tensioning the integral structure. And the kinematics of the tensioned monolithic structure is analyzed during the structure design process. However, due to the complexity of the structure, the design of a dynamic model and a control method of the whole stretching bionic structure is not considered when the two kinds of whole stretching bionic structures are designed, and the operation conditions of the whole stretching bionic structure under the noise conditions such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like are not considered in the two kinds of bionic structures.

In conclusion, the further research on the bionic stretching integral structure based on the bionic human body lower limb joint dynamics analysis is a key link of the bionic lower limb joint structure. Therefore, the invention provides a bionic knee joint structure based on a tension integral structure. Based on the principle of bionics, the knee joint of the lower limb of the human body is regarded as a rigid-flexible coupling mechanism. The rod structure of the tensegrity structure may be considered as the bone of the knee joint, while the tissue of the knee joint, muscles, ligaments, etc., may generally be considered as the string structure of the tensegrity structure. In addition, the limit function of the knee joint patella and the tissues nearby the knee joint patella on the knee joint is considered, and the limit function of the bionic knee joint structure is realized by utilizing the two-link structure under the condition of applying external force. In addition, kinematic and kinetic models of a biomimetic knee joint structure based on a tensegrity structure were analyzed. Furthermore, because the knee joint can generate moment in the rehabilitation process, the influence of the moment of the human knee joint on the bionic knee joint dynamic model in the rehabilitation process is considered in the bionic knee joint structure design. Finally, in the operation process of the bionic knee joint, noise items such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like are inevitable, so that an NTZNN model with anti-noise performance is designed, and a control method design is carried out on the bionic knee joint structure. And the noise items such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like are added in the NTZNN model, so that the bionic knee joint structure operation is not influenced.

Disclosure of Invention

The invention relates to a bionic knee joint structure based on a stretching integral structure and a control method design, under the condition of conforming to the bionic principle of the knee joint of lower limbs of a human body, the technical scheme of the invention is as follows:

a bionic knee joint structure based on a tension integral structure and a control method design are disclosed, the contents of the design of the knee joint bionic structure and the control method thereof are as follows:

s1: based on the principle of bionics, the bones, muscles and ligaments which bear different functions when the knee joint of a human body moves are simplified into a rope and rod structure of a tensioning integral structure.

S2: and (4) analyzing the kinematic properties of the bionic knee joint structure based on the tension integral structure established in the S1, wherein the kinematic properties comprise a geometric structure, a singular configuration and a working interval.

S3: according to the limit function of the human knee joint during movement, under the condition of applying external force to the bionic knee joint structure, the limit function of the bionic knee joint is realized by utilizing the two-link structure.

S4: the method considers that the human lower limbs can generate different human knee joint moments in different rehabilitation training stages in the rehabilitation process, and considers the influence of the moments generated by the human lower limbs on the bionic knee joint structure dynamic model.

S5: and the kinetic energy and the potential energy of the bionic knee joint structure are analyzed, and the dynamic modeling of the structure is completed.

S6: and controlling the bionic knee joint structure by using an NTZNN model.

The specific process of step S1 is:

s101: in order to convert the knee joint into a tension integral structure at a bionic angle, complex tissues such as bones, muscles, ligaments and the like of the knee joint need to be simplified into a rope and rod structure so as to facilitate subsequent analysis. According to the action condition of the lower limbs of the human body during movement, the tissues with basically the same functions are simplified into the same rope and rod structure.

S102: by this strategy, the popliteal hamstring and tibialis anterior muscles are reduced to one muscle. The sartorius, semimembranus, gracilis and semitendinosus muscles are reduced to one muscle. The quadriceps muscle is reduced to a single muscle. In addition, the gastrocnemius can be regarded as a muscle. As for bones, fibula and tibia are considered to be one bone because they function similarly. The femur can be considered as a piece of bone. In addition, due to its special stopper function, the tissues that the patella and the adjacent ligaments perform the same function are simplified into two rods.

The specific process of step S2 is:

s201: the human knee joint structure is simplified into a four-rod four-rope stretching integral structure.

S202: by singular configuration is meant the situation where a degradation between the input and output of the structure occurs.

S203: in the invention, because the bionic knee joint has a limit function, the bionic knee joint structure can not reach the theoretical singular configuration when being subjected to straightening movement. Therefore, the singular configuration of the bionic knee joint structure in the patent during the extension movement is actually the same as the upper limit of the working interval, and the singular configuration of the bionic knee joint structure during the flexion movement can theoretically reach, however, reaching the singular configuration in the actual movement of the bionic knee joint structure means that the bionic knee joint structure is completely compressed, and when the bionic knee joint structure continues in the state, the bionic knee joint structure may be damaged. This should be avoided and excessive flexion of the knee joint can also cause damage to the knee joint during actual movement of the human knee joint.

S204: when the integral stretching structure is designed, the working interval is an important index, and in the patent, ADAMS software is used for simulating the bionic knee joint structure. The emulation shows, under the effect of external force, the bionic knee joint structure based on stretch-draw overall structure that this patent relates to can satisfy the knee joint motion and realize the limit function when human knee joint stretches the motion.

The specific process of step S3 is:

s301: because tissues such as the patella of the human knee joint and ligaments and muscles nearby the patella have a limiting function on the knee joint, the knee joint is prevented from being excessively straightened during movement, and the injury to the human body is avoided. Therefore, in order to embody the bionic performance of the bionic knee joint structure, the limit function of the knee joint needs to be designed when the bionic knee joint structure is designed.

S302: the bionic knee joint structure adopts two groups of two link mechanisms which are respectively connected with the bionic patella front edge plane through a steering mechanism, when external force acts on a connecting rod, the connecting rod moves upwards due to the external force, and when the connecting rod connected with the steering mechanism is perpendicular to an x axis, the connecting rod structure reaches the upper bound of a working interval and cannot move continuously, so that the limiting function when external force is applied to the bionic knee joint is realized.

S303: in the bionic knee joint structure, the first segment connecting rod structure comprising the steering structure and the connecting rod structure connected with the steering structure is regarded as a simplified patellar structure. When the bionic knee joint structure carries out rehabilitation activities, the bionic knee joint structure mainly adopts a rod structure formed by simplifying thighbones, fibulas and shinbones and four rope structures formed by simplifying muscles to bear rehabilitation functions. Therefore, in order to simplify the bionic patella structure as much as possible, but also ensure that the bionic patella structure can realize the main bionic function, namely, the extension movement of the bionic knee joint can be limited under the action of external force, so that the steering structure is fixed. Meanwhile, from the perspective of bionics, the patella and the tissue similar to the patella function mainly play two biological functions in motion. Firstly, it allows a wider distribution of pressure on the femur by increasing the contact area of the patellar tendon and the patella, and on the other hand it assists in the extension of the knee joint by producing a forward displacement of the quadriceps tendon throughout the range of motion. However, from full extension to full flexion of the knee joint, the patella slides approximately 7cm between the femoral condyles. The range of motion of the patella is quite small relative to the full motion of the knee joint, i.e., the range from fully flexed to fully straightened. On the other hand, the front edge of the patella is rough, the rear edge of the patella is smooth, the displacement of the front edge of the patella relative to the femur is not obvious when the knee joint moves, and the main function is to protect the quadriceps femoris tendon. When the knee joint moves, the movement of the patella relative to the quadriceps femoris tendon tends to be driven outward. In summary, the present invention is directed to simplifying the structure of the biomimetic knee joint to facilitate the establishment of the kinetic model, and to ensure the physiological function of the patella. So that the rotary joint is fixed on the bionic patella leading edge plane.

The specific process of step S4 is:

human body knee joint moment tau with different sizes can be generated by human body lower limbs in different rehabilitation stages in the rehabilitation training process_R. For example, in the passive rehabilitation stage, the lower limbs are hemiplegic due to diseases such as stroke, the limbs do not move coordinately so that the lower limbs can not move according to the will of the patient, and the human body can generate the anti-rehabilitation training track in the rehabilitation training processMoment, so the moment tau of the knee joint of the human body is generated in the rehabilitation training process_RIs an antagonistic moment, and can be set with tau in the process of establishing a dynamic model_RIs negative. In addition, there is a complete passive rehabilitation phase, which corresponds to the basic loss of the nerve conduction function between the central nervous system and the skeletal muscles of the lower limbs of the patient, and can also be considered as a passive rehabilitation phase for patients who have undergone a lower limb joint operation or a total knee replacement operation, in which the moment τ of the human knee joint is present_RAre very small. Aiming at the condition that a patient can generate moment actively following a rehabilitation training track at the end stage of a rehabilitation training stage, the moment tau of the knee joint of the human body is generated at the moment_RPositive values can be assumed in the kinetic model. In conclusion, in the dynamic model building process, the human knee joint moment tau_RPlay an important role. Human knee joint moments should be reflected in the system dynamics modeling to represent the effect of human generated forces on the motion of the biomimetic knee joint structure. Because the human knee joint moment is basically consistent in different rehabilitation stages, the human knee joint moment tau can be considered in stages_R。

The specific process of step S5 is:

after analyzing the kinetic energy and potential energy of the integral structure, the Lagrange equation is obtained, namely:

where K is kinetic energy, P is potential energy, and f ═ f₁,f₂]^TIs a non-conservative force and q ═ θ, γ]^TIs a generalized coordinate vector.

The specific process of step S6 is:

s601: the anti-noise type return-to-zero error dynamics model may be defined by:

s602: in addition, the NTZNN model is expressed as follows:

where β, λ are coefficients, δ are time intervals, and ε (t) is a noise term.

S603: after using the NTZNN model, epsilon (t) can be considered as noise encountered by the bionic knee joint structure in the rehabilitation process in the bionic knee joint structure mentioned in the patent, and the noise includes factors such as mechanical structure error, mechanical vibration, friction between components, noise of feedback signals, external static friction and the like.

Statement of the drawings

FIG. 1 is a geometric structure diagram of a bionic knee joint structure based on a tension integral structure;

FIG. 2 is a diagram showing the relationship between the load and deformation of a knee joint of a human body under the action of an external force;

in FIG. 3 is_RWhen the angle theta is equal to-40, an error curve between the actual track and the expected track is formed;

in FIG. 4 is_R-40, the error curve between the actual trajectory and the desired trajectory for the γ angle;

in FIG. 5 is_RWhen the track is-40, the actual track is compared with the expected track;

FIG. 6 is a drawing showing_RWhen the angle theta is equal to 40, an error curve between the actual track and the expected track is formed;

FIG. 7 is a drawing showing_RWhen the angle is 40, an error curve between the actual track and the expected track is formed by the angle gamma;

in FIG. 8, is_RWhen 40, the actual track is compared with the expected track;

FIG. 9 is [ tau ]_RWhen the angle theta is equal to 0, an error curve between the actual track and the expected track is formed;

FIG. 10 is a drawing showing_RWhen the angle is equal to 0, an error curve between the actual track and the expected track of the angle gamma;

FIG. 11 is a drawing showing_RWhen 0, the actual trajectory is compared to the desired trajectory.

Detailed Description

The invention will be further illustrated with reference to the following examples and drawings in the description:

fig. 1 is a geometric structure diagram of a bionic knee joint structure based on a tensegrity structure, as shown in fig. 1, the structure is specifically as follows:

s1 the geometrical structure of the bionic knee joint structure is as follows:

s101: the bionic knee joint tensioning integral structure consists of four rods and four groups of rope structures. In the biomimetic knee joint structure, the rods AC and BD can be regarded as skeletal structures simplified from the femur, tibia and fibula, respectively. Rods CF and DE can be considered as structures with the same function, simplified from the patella and the adjacent tissue. For a two-bar linkage, the lengths of the rods AC and CF are L, respectively₁And L₂Wherein L is₁Greater than L₂. Similarly, the other two-bar linkage BD-DE and the two-bar linkage AC-CF are axisymmetric about the y-axis, so that the two geometries are identical. It should be noted that the two sets of two-bar linkages do not contact each other, so that the two sets of two-bar linkages do not interfere with each other during movement.

S102: for a four-set rope configuration, the initial length s_0iThe reason why (i ═ 1,2,3 and 4) is not equal to 0 is that when the joints of the lower limbs of the human body do not move, the muscles and ligaments of the human body have certain initial lengths so as to keep the stability of the structures of the lower limbs of the human body. In this patent, k₁、s₁And s₀₁Are respectively equal to k₂、s₂And s₀₂。s₀₄Is greater than s₀₃. Stiffness k of the cord compared to the rod_iAnd (i ═ 1,2,3,4) is infinitesimal.

S103: the nodes A and B can translate left and right along the x axis without friction, and the nodes E and F are used as rotating joints to be fixed on the bionic patella front edge plane. The distance from the node E, F to the origin of the reference coordinate system is L₃。

Fig. 2 is a relationship diagram of the load and deformation of the human knee joint under the action of external force, and as shown in fig. 2, the structure is specifically as follows:

s2: the relationship between the load and the deformation of the human knee joint under the action of external force is as follows:

fig. 2 shows the deformation relationship of muscles relative to external load when the human knee joint is in motion. Therefore, in order to embody the bionic performance of the bionic knee joint structure, a muscle viscoelasticity characteristic similar to the spring damping coefficient should be considered in the model design at the elastic range stage.

S3: under the action of external force, the working interval of C, D points in the bionic knee joint structure is as follows:

in ADAMS dynamic simulation, the bionic knee joint structure forms a motion track of C, D points under the action of external force applied to C, D points. Simulation results show that when the knee joint is simulated to be in extension movement, namely external force which is applied upwards and is perpendicular to the x axis is at C, D points, when the CF rod and the DE rod are completely perpendicular to the x axis, the structure is locked and cannot move continuously. Therefore, the bionic knee joint structure can be seen to rotate upwards from a balance position, namely an initial position, under the action of external force, and when CF and DE are perpendicular to an x axis, namely the upper bound of a working range. Because the connecting rod structure has the limiting function under the action of external force, the connecting rod structure cannot move continuously, and the limiting function of the knee joint mechanism in the process of extension movement of the knee joint is realized.

S4: the influence of human knee joint moment on the whole tensioning structure and the processing method thereof are as follows:

in the process of rehabilitation of the lower limbs of the human body, the human body knee joint moments with different sizes can be generated when the lower limbs of the human body are in different rehabilitation stages. For example, in the passive rehabilitation stage, the lower limbs are hemiplegic due to diseases such as stroke and the like, the limbs do not move coordinately so that the lower limbs can not move according to the will of the patient, and the human body can generate the moment resisting the rehabilitation training track in the rehabilitation training process, so the moment tau of the knee joint of the human body is generated in the rehabilitation training process at the moment_RIs an antagonistic moment, and can be set with tau in the process of establishing a dynamic model_RIs negative. In addition, there is a complete passive rehabilitation phase, which corresponds to the basic loss of the nerve conduction function between the central nervous system and the skeletal muscles of the lower limbs of the patient, and can also be considered as a passive rehabilitation phase for patients who have undergone a lower limb joint operation or a total knee replacement operation, in which the moment τ of the human knee joint is present_RIs very small, so τ_RMay take a value of 0. Aiming at the fact that a patient can generate an active following rehabilitation training track in the end stage of rehabilitation training phaseMoment of trace, moment of human knee joint_RPositive values can be assumed in the kinetic model. These moments are not negligible during the modeling process. Therefore, the human knee joint moment tau is considered in the dynamic model_RHuman knee joint moment tau_RCan be considered constant because the moments produced by the lower limbs are approximately the same during the same rehabilitation phase. Thus, τ_R＝[Ω，Ω]^TWhere Ω is a constant.

S5: the dynamic modeling of the bionic knee joint structure based on the integral tensioning structure is as follows:

in the process of modeling the dynamic equation of the bionic knee joint, in order to analyze the kinetic energy and the potential energy of the system, the Lagrange equation is used for modeling, and the method specifically comprises the following steps:

where K is kinetic energy, P is potential energy, f is a non-conservative force vector and q ═ θ, γ]^TIs a generalized coordinate vector. In particular, the bionic knee joint structure based on the tension integral structure is a two-degree-of-freedom structure. Therefore, the generalized coordinates of the system can be chosen as: theta, gamma, with q ═ theta, gamma]^T。

S501: in this patent, the kinetic energy of the system is due to the motion of the rod. Therefore, the kinetic energy of the bionic knee joint structure is as follows:

wherein m is₁And m₂Respectively being rods L₁And a rod L₂The quality of (c).

S502: the potential energy of the system is as follows:

wherein α ═ θ + γ -pi.

S503: the non-conservative force vector f is represented by:

wherein, c_iI-1, 2,3,4 is the damping coefficient of the spring, where c₁＝c₂＝c₃＝c₄The equal damping coefficients of the springs are understood to mean that the coefficients of the muscles and the like near the knee joint of the human body are substantially the same in the elastic range shown in fig. 2.

S504: thus, the lagrangian equation from which the kinetic model can be derived is as follows:

whereinu and τ_RRespectively a control moment and a human knee joint moment. C is a matrix associated with the non-conservative force vector, and T is associated with potential energy.

S505: in addition, the matrix M, H, G is specifically:

s6: the NTZNN controller is in a specific form as follows:

because the moment tau of the human knee joint is considered in the model_RAnd factors such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like which are inevitable when the bionic knee joint structure is operated are considered during dynamic modeling, so that the dynamic model is influenced. The NTZNN model with noise immunity is considered to design a controller of a bionic knee joint structure dynamics model.

S601: the nonlinear optimization problem can be summarized as:

s602: the objective function is derived over time as:

wherein:

s603: the error function of the NTZNN model may be defined by:

e(t)＝0-φ(y(t))

s604: the NTZNN model may be defined by the following formula:

wherein, beta and lambda are constant coefficients larger than 0, and epsilon (t) is a noise term.

As can be seen from fig. 3-11. Moment tau of human knee joint_RThe values of-40, 40 and 0 are respectively selected to correspond to different possible stages in the rehabilitation training stage of the patient, namely a passive rehabilitation stage, an active rehabilitation stage and a complete passive rehabilitation stage. The experimental result shows that the moment tau of the knee joint of the human body is added_RThen, the dynamic model of the bionic knee joint structure is influenced, and the performance requirements can still be met. In addition, in the establishing process of the bionic knee joint structure dynamic model, factors such as mechanical structure errors, mechanical vibration, friction among components, noise of feedback signals, external static friction and the like which are possibly generated in the operation process of the bionic knee joint structure are considered. After the NTZNN model is used as the controller, the model can always control the actual track to track the rehabilitation training track in time and still meet the requirement of expected error.