Adjustable knee joint training device and control method thereof

Abstract

The application discloses an adjustable knee joint training device and a control method thereof, and belongs to the field of rehabilitation apparatuses, and comprises a waist support mechanism, an adjusting upper plate connected with the waist support mechanism through a rotation limiting nut, an adjusting lower plate slidably connected with the adjusting upper plate through two adjusting slide rails, an upper and lower plate connecting seat fixed on the adjusting lower plate, an adjusting lower pressing button installed on the upper and lower plate connecting seat, a motor fixed on the adjusting lower plate, and a lower leg and foot mechanism connected with the motor output end. The waist support mechanism and a thigh mechanism can rotate relative to each other, so that the angle between the two can be adjusted. The thigh mechanism and the lower leg and foot mechanism are connected through the motor, and the lower leg and foot mechanism can rotate relative to the thigh mechanism by starting the motor, so that the knee joint of a user can be subjected to flexion and extension rehabilitation training movement. The application realizes length adjustment of the lower leg and angle adjustment of the foot, and has the advantages of small occupied space, small volume, simple structure and convenient assembly.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rehabilitation equipment, and particularly relates to an adjustable knee joint training device and a control method thereof. BACKGROUND

[0002] With the development of science and technology, the existing rehabilitation equipment is increasingly powerful, and is developing towards humanization and intelligentization. The knee joint rehabilitation robot replaces the rehabilitation physician to engage in repetitive and heavy rehabilitation nursing, and improves the utilization rate of medical resources. The market demand for knee joint rehabilitation training devices shows a steady upward trend. This is not only due to the improvement of national health consciousness, but also due to the increase in rehabilitation needs brought by an aging society and the increase in patients with knee joint dysfunction caused by various sports injuries and occupational diseases. It is expected that in the future, with the progress of medical technology and the deepening of rehabilitation concepts, the market demand for knee joint rehabilitation training devices will continue to expand.

[0003] The design of the knee joint rehabilitation training device is derived from the in-depth understanding of the structure and function of the human knee joint and the in-depth research on the principles of rehabilitation medicine. With the continuous progress of medical technology, the knee joint rehabilitation training device has evolved from a simple mechanical device to an intelligent device. Early knee joint rehabilitation training devices were mostly manually adjustable, with relatively simple functions and unable to meet the complex and varied rehabilitation needs. With the development of technology, electric and intelligent knee joint rehabilitation training devices have gradually emerged, providing more comprehensive and effective support for patient rehabilitation. At present, the knee joint rehabilitation training device has made significant progress. Some high-end knee joint rehabilitation training devices use advanced robotic technology, such as series rehabilitation robots, parallel rehabilitation robots, and hybrid rehabilitation robots. These robotic technologies can achieve more complex and precise rehabilitation training, improving rehabilitation effectiveness. At the same time, with the continuous development of technologies such as the Internet of Things and big data, knee joint rehabilitation training devices are gradually realizing remote monitoring, data analysis, and other functions, providing more convenient and efficient support for patient rehabilitation. With the continuous progress of technology and the continuous development of rehabilitation medicine, the knee joint rehabilitation training device technology will have a broader development space.

[0004] In the prior art, a knee joint rehabilitation auxiliary device disclosed by Chinese patent CN221888668U includes a base with a mounting groove on the top, a limiting groove is formed on the inner side wall of the mounting groove, a sliding block is arranged on the inner side wall of the limiting groove, and a bending assembly is arranged at the top end of the sliding block; a display screen is arranged on the top surface of the base, and a driving assembly is arranged on the inner side wall of the bottom end of the base; a control console is arranged on the side of the base. The forward and reverse rotation of the motor is controlled by pressing the buttons on the surface of the control console to drive the rotation of the lead screw. At this time, the sliding block moves along the inner walls of the mounting groove and the limiting groove under the driving of the lead screw. The two groups of lead screws are arranged in opposite directions to realize the gathering of the sliding blocks, so as to change the angle of the supporting plate in the bending assembly, meet the different bending angles of the knee joint, and further help the rehabilitation of the knee joint of the patient. The technical solution has the following problems: the lower leg part does not have a length adjusting function, and the foot part does not have an angle adjusting function. Moreover, the overall device occupies a large space, and the complex structure makes the assembly inconvenient. SUMMARY

[0005] Therefore, in order to solve the technical problems existing in the prior art knee joint rehabilitation training device, the present application provides an adjustable knee joint training device and a control method thereof.

[0006] The technical solution adopted by the present application to solve the technical problems is as follows:

[0007] The adjustable knee joint training device of the present application specifically includes the following components:

[0008] A waist support mechanism;

[0009] An adjusting upper plate connected to the waist support mechanism through a rotating limiting nut; a plurality of evenly distributed limiting grooves are arranged on the adjusting upper plate;

[0010] An adjusting lower plate slidingly connected to the adjusting upper plate through two adjusting sliding rails;

[0011] An upper and lower plate connecting seat fixed on the adjusting lower plate;

[0012] An adjusting lower pressing button mounted on the upper and lower plate connecting seat; the adjusting lower pressing button includes a button end cover, a limiting column and a limiting pin connected in sequence, and the limiting pin is placed in the limiting groove on the adjusting upper plate; pressing the button end cover makes the lower end of the limiting column contact the adjusting upper plate, and the limiting pin is unlocked by being separated from the limiting groove in the adjusting upper plate;

[0013] A motor fixed on the adjusting lower plate;

[0014] A lower leg and foot mechanism connected to the output end of the motor.

[0015] Further, the waist support mechanism comprises a waist support mechanism inner shell, a shell connecting seat and a waist support mechanism outer shell connected in sequence, and a thigh connecting seat fixed on the upper end of the shell connecting seat; the thigh connecting seat is connected with a rotating limiting nut.

[0016] Further, the thigh connecting seat is provided with a thigh limiting pin, the upper end of the shell connecting seat is provided with a limiting pin mounting hole and a circular mounting hole, the limiting pin mounting hole is in communication with the circular mounting hole; the thigh limiting pin is mounted in the limiting pin mounting hole; the head of the rotating limiting nut is semicircular in shape, and a semicircular protrusion is arranged on the upper side of the head; one end of the thigh limiting pin extends into the circular mounting hole from the limiting pin mounting hole, and the end of the thigh limiting pin is clamped on the left side of the semicircular protrusion of the head of the rotating limiting nut; at this time, the rotating limiting nut is in a horizontal position, and when the waist support mechanism is pushed upward, the thigh limiting pin is pushed upward through the shell connecting seat.

[0017] Further, it further comprises a thigh mechanism outer shell, and the rotating limiting nut, the adjusting upper plate, the adjusting lower pressing button, the upper and lower plate connecting seat, the adjusting lower plate and the two adjusting slide rails are all mounted in the thigh mechanism outer shell.

[0018] Further, the adjusting upper plate is provided with two strip-shaped holes, and the two adjusting slide rails are respectively mounted in the two strip-shaped holes, so that the adjusting upper plate and the adjusting lower plate are slidably connected.

[0019] Further, the upper and lower plate connecting seat is in the shape of U, and the adjusting upper plate passes through the lower part of the U-shaped upper and lower plate connecting seat.

[0020] Further, the lower leg and foot mechanism comprises a motor driven gear mounted on the output shaft of the motor, an adjusting secondary lever connected with the motor driven gear, an extension adjusting seat connected with the adjusting secondary lever, an adjusting main rod connected with the extension adjusting seat through a lower leg adjusting knob, a foot support fixing seat connected with the adjusting main rod through a foot adjusting knob, and a foot support fixed on the foot support fixing seat.

[0021] Further, the foot support fixing seat is in the shape of U, and the foot support is fixed in the U-shaped foot support fixing seat.

[0022] Further, the lower end of the adjusting main rod is provided with a plurality of uniformly distributed bolt holes, the foot adjusting knob is screwed into the corresponding bolt hole, and the adjusting main rod and the foot support fixing seat are connected and fixed through the foot adjusting knob.

[0023] Further, the lower leg and foot mechanism further comprises a caster connecting shaft mounted on the lower end of the foot support fixing seat, and two casters respectively mounted on the two ends of the caster connecting shaft.

[0024] Further, the calf and foot mechanism further comprises a foot mechanism shell, and the motor driven gear, the adjusting secondary lever, the telescopic adjusting seat, the calf adjusting knob, the adjusting main lever and the foot adjusting knob are all installed in the foot mechanism shell.

[0025] The application further provides a control method of the adjustable knee joint training device, which specifically comprises the following steps:

[0026] Step S1: the total mass of the calf and foot mechanism and the motor is measured as m1, and the total mass of the thigh mechanism is measured as m2; the gravity center positions of the calf and foot mechanism and the thigh mechanism are extracted by using a CAD model, and the distance L1 between the center axis of the motor output shaft and the gravity center of the calf and foot mechanism and the distance L2 between the center axis of the motor output shaft and the gravity center of the thigh mechanism are calculated;

[0027] Step S2: the angle between the thigh mechanism and the calf and foot mechanism is manually driven to rotate from 180° to 130°, and the actual rotation angle of the thigh mechanism is recorded as α, and the linkage coefficient k is obtained by linear fitting as k = α / θ;

[0028] Step S3: a real-time compensation process is performed during movement;

[0029] The current rotation angle θ of the calf and foot mechanism is collected in real time by the encoder arranged at the center axis of the motor output shaft; the total gravity torque of the device is calculated as Mtotal = m1·g·L1·cos(θ) + m2·g·L2·cos(k·θ), wherein g is the acceleration of gravity; the total gravity torque of the device is converted into a motor control signal, and the motor is driven to output a corresponding torque according to the current rotation angle θ of the calf and foot mechanism collected in real time to compensate the gravity torque.

[0030] The application has the following beneficial effects:

[0031] The application provides an adjustable knee joint training device, which mainly comprises a waist support mechanism, a thigh mechanism, a calf and foot mechanism and a motor.

[0032] The application can adjust the length of the calf and the angle of the foot according to the conditions of different users, so that the device can be applied to more users. Meanwhile, the device has a small footprint, a small volume, a simple structure and is convenient to assemble.

[0033] In addition, the control method of the adjustable knee joint training device is based on gravity compensation to realize control of the knee joint training device, can accurately calculate and compensate gravity torque in real time, overcome the torque generated by the weight of the device around the rotating shaft, and improve the control accuracy of the device. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A structural schematic diagram of the adjustable knee joint training device is provided.

[0035] Figure 2 An exploded view of the waist support mechanism.

[0036] Figure 3 A structural schematic diagram of the waist support mechanism.

[0037] Figure 4 A structural schematic diagram of the thigh mechanism.

[0038] Figure 5 The position connection relationship between the adjusting down button and the adjusting upper plate.

[0039] Figure 6 The position connection relationship among the adjusting upper plate, the rotating limiting nut and the thigh connecting seat.

[0040] Figure 7 A structural schematic diagram of the calf and foot mechanism.

[0041] Figure 8 A torque identification diagram.

[0042] Figure 9 An angle identification diagram.

[0043] Figure 10 A control method flow chart of the adjustable knee joint training device is provided.

[0044] In the figure, the waist support mechanism 1, the waist support mechanism inner shell 1.1, the thigh connecting seat 1.2, the thigh limiting pin 1.2.1, the shell connecting seat 1.3, the limiting pin mounting hole 1.3.1, the circular mounting hole 1.3.2, the waist support mechanism outer shell 1.4, the plate 1.4.1, the thigh mechanism 2, the rotating limiting nut 2.1, the limiting groove 2.2.1, the adjusting upper plate 2.2, the adjusting lower pressing button 2.3, the button end cover 2.3.1, the limiting column 2.3.2, the limiting pin 2.3.3, the upper and lower plate connecting seat 2.4, the adjusting lower plate 2.5, the thigh mechanism outer shell 2.6, the first adjusting sliding rail 2.7, the second adjusting sliding rail 2.8, the power socket 2.9, the first handle 2.10, the lower leg and foot mechanism 3, the motor driven gear 3.1, the adjusting auxiliary rod 3.2, the telescopic adjusting seat 3.3, the lower leg adjusting knob 3.4, the adjusting main rod 3.5, the foot adjusting knob 3.6, the first caster 3.7, the second caster 3.8, the caster connecting shaft 3.9, the foot support 3.10, the foot support fixing seat 3.11, the foot mechanism outer shell 3.12, the second handle 3.13, the motor 4. DETAILED DESCRIPTION

[0045] The application will be further described in detail below with reference to the accompanying drawings.

[0046] In a first aspect, the application provides an adjustable knee joint training device.

[0047] As shown in the drawings, the application provides an adjustable knee joint training device, which mainly consists of the following components: Figures 1-7

[0048] The waist support mechanism 1, the thigh mechanism 2, the lower leg and foot mechanism 3, and the motor 4.

[0049] The connection relationship between them is that the waist support mechanism 1 is connected to one end of the thigh mechanism 2, and the lower leg and foot mechanism 3 is connected to the other end of the thigh mechanism 2 through the motor 4.

[0050] As shown in the drawings, the application provides an adjustable knee joint training device, which mainly consists of the following components: Figure 2 Figure 3 ​​As shown, the lumbar support mechanism 1 of this invention mainly consists of an inner shell 1.1, a thigh connecting seat 1.2, a shell connecting seat 1.3, and an outer shell 1.4. The inner shell 1.1, shell connecting seat 1.3, and outer shell 1.4 are sequentially connected together, with the shell connecting seat 1.3 positioned between the inner shell 1.1 and the outer shell 1.4. The thigh connecting seat 1.2 is then fixed to the upper end of the shell connecting seat 1.3. A plate 1.4.1 for supporting the lumbar region is provided on the outer side of the outer shell 1.4. The thigh connecting seat 1.2 is provided with a thigh limiting pin 1.2.1, and the upper end of the shell connecting seat 1.3 is provided with a limiting pin mounting hole 1.3.1. The thigh limiting pin 1.2.1 is installed in the limiting pin mounting hole 1.3.1 of the shell connecting seat 1.3, thereby connecting the thigh connecting seat 1.2 and the shell connecting seat 1.3.

[0051] like Figure 4 As shown, the thigh mechanism 2 of this invention mainly consists of a rotary limiting nut 2.1, an upper adjusting plate 2.2, an adjusting press button 2.3, an upper and lower plate connecting seat 2.4, an adjusting lower plate 2.5, a thigh mechanism housing 2.6, a first adjusting slide rail 2.7, a second adjusting slide rail 2.8, a power socket 2.9, and a first handle 2.10. The rotary limiting nut 2.1, the upper adjusting plate 2.2, the adjusting press button 2.3, the upper and lower plate connecting seat 2.4, the adjusting lower plate 2.5, the first adjusting slide rail 2.7, and the second adjusting slide rail 2.8 are all installed in the thigh mechanism housing 2.6. The upper adjusting plate 2.2 and the lower adjusting plate 2.5 are slidably connected. Specifically, the upper adjusting plate 2.2 has two slotted holes. The first adjusting slide rail 2.7 and the second adjusting slide rail 2.8 are respectively inserted into the two slotted holes of the upper adjusting plate 2.2, and then the bottoms of the first adjusting slide rail 2.7 and the second adjusting slide rail 2.8 are fixed to the lower adjusting plate 2.5.

[0052] The outer end of the upper adjustment plate 2.2 is connected to the thigh connecting seat 1.2 in the lumbar support mechanism 1 via a rotating limiting nut 2.1. The upper and lower plate connecting seat 2.4 is fixed on the lower adjustment plate 2.5, wherein the upper and lower plate connecting seat 2.4 is U-shaped, and the upper adjustment plate 2.2 should pass through the lower U-shape of the upper and lower plate connecting seat 2.4. The adjustment pressing button 2.3 is installed on the upper and lower plate connecting seat 2.4, and the adjustment pressing button 2.3 should be located in the middle position of the upper and lower plate connecting seat 2.4. The fixed end of the motor 4 is fixed to the inner end of the lower adjustment plate 2.5. The power socket 2.9 is fixed on the inner wall of the thigh mechanism housing 2.6 and is used to connect the motor 4 to an external power source to supply power to the motor 4. The first handle 2.10 is fixed on the outer wall of the thigh mechanism housing 2.6.

[0053] Press the adjustment lower button 2.3 while moving the adjustment upper plate 2.2, so that the adjustment upper plate 2.2 moves on the adjustment lower plate 2.5 along the first adjustment slide rail 2.7 and the second adjustment slide rail 2.8, thereby realizing the length adjustment of the thigh mechanism 2; wherein, the movement of the adjustment upper plate 2.2 to the opposite side of the motor 4 is to increase the length of the thigh mechanism 2, and the movement of the adjustment upper plate 2.2 to the side of the motor 4 is to decrease the length of the thigh mechanism 2.

[0054] The position connection relationship between the adjustment lower button 2.3 and the adjustment upper plate 2.2 is as shown in Figure 5 The adjustment lower button 2.3 mainly consists of a button end cover 2.3.1, a limiting column 2.3.2 and a limiting pin 2.3.3, wherein, the button end cover 2.3.1, the limiting column 2.3.2 and the limiting pin 2.3.3 are sequentially connected and fixed, and then the limiting pin 2.3.3 is placed in the limiting slot 2.2.1 on the adjustment upper plate 2.2 (the number of the limiting slot 2.2.1 on the adjustment upper plate 2.2 can be designed according to the length of the adjustment upper plate 2.2, without specific limitation); before unlocking, the limiting pin 2.3.3 should be located in the limiting slot 2.2.1 on the adjustment upper plate 2.2, and when unlocking, the button end cover 2.3.1 is pressed first to make the limiting column 2.3.2 contact the adjustment upper plate 2.2, so that the limiting pin 2.3.3 is separated from the limiting slot 2.2.1 in the adjustment upper plate 2.2, thereby realizing the unlocking of the adjustment upper plate 2.2.

[0055] The position connection relationship among the adjustment upper plate 2.2, the rotating limiting nut 2.1, the thigh connecting seat 1.2 and the shell connecting seat 1.3 is as shown in Figure 6 The thigh limiting pin 1.2.1 on the thigh connecting seat 1.2 is installed in the limiting pin installation hole 1.3.1 of the shell connecting seat 1.3, and the head of the rotating limiting nut 2.1 is installed in the circular installation hole 1.3.2 of the shell connecting seat 1.3, wherein, the limiting pin installation hole 1.3.1 is in communication with the circular installation hole 1.3.2; the head of the rotating limiting nut 2.1 is semicircular in shape, and a semicircular protrusion is arranged on the upper side thereof; one end of the thigh limiting pin 1.2.1 extends into the circular installation hole 1.3.2 from the limiting pin installation hole 1.3.1, and the end of the extending end of the thigh limiting pin 1.2.1 is clamped on the left side of the semicircular protrusion of the head of the rotating limiting nut 2.1; as shown in Figure 6 The rotating limiting nut 2.1 is in a horizontal position at this time, and when the waist support mechanism 1 is pushed upward, the thigh limiting pin 1.2.1 is pushed upward by the shell connecting seat 1.3.

[0056] As shown in Figure 1 and Figure 7As shown, the calf and foot mechanism 3 in the application mainly consists of a motor driven gear 3.1, an adjusting auxiliary rod 3.2, an extension adjusting seat 3.3, a calf adjusting knob 3.4, an adjusting main rod 3.5, a foot adjusting knob 3.6, a first caster wheel 3.7, a second caster wheel 3.8, a caster wheel connecting shaft 3.9, a foot support 3.10, a foot support fixing seat 3.11, a foot mechanism shell 3.12 and a second handle 3.13. The foot support fixing seat 3.11 is in a U-shaped structure, the first caster wheel 3.7 and the second caster wheel 3.8 are respectively installed at both ends of the caster wheel connecting shaft 3.9, the caster wheel connecting shaft 3.9 is installed at the lower end of the U-shaped structure of the foot support fixing seat 3.11, and the foot support 3.10 is fixed in the U-shaped structure of the foot support fixing seat 3.11. The motor driven gear 3.1, the adjusting auxiliary rod 3.2, the extension adjusting seat 3.3, the calf adjusting knob 3.4, the adjusting main rod 3.5 and the foot adjusting knob 3.6 are all installed in the foot mechanism shell 3.12. Among them, the motor driven gear 3.1 is installed on the output shaft of the motor 4, and the motor driven gear 3.1 can be driven to rotate by the motor 4. One end of the adjusting auxiliary rod 3.2 is connected with the motor driven gear 3.1, the other end of the adjusting auxiliary rod 3.2 is connected with one end of the extension adjusting seat 3.3, the other end of the extension adjusting seat 3.3 is connected with the adjusting main rod 3.5 through the calf adjusting knob 3.4, and the other end of the adjusting main rod 3.5 is connected with one side of the upper end of the U-shaped structure of the foot support fixing seat 3.11 through the foot adjusting knob 3.6. Specifically, the calf adjusting knob 3.4 and the foot adjusting knob 3.6 can be realized in the form of bolts, the upper end of the adjusting main rod 3.5 is inserted into the extension adjusting seat 3.3, and then the adjusting main rod 3.5 is connected and fixed with the extension adjusting seat 3.3 through the calf adjusting knob 3.4, and similarly, the lower end of the adjusting main rod 3.5 is provided with a plurality of uniformly distributed bolt holes, the foot adjusting knob 3.6 is screwed into the corresponding bolt hole, and the adjusting main rod 3.5 is connected and fixed with the foot support fixing seat 3.11 through the foot adjusting knob 3.6. The second handle 3.13 is fixed on the foot mechanism shell 3.12.

[0057] When the length of the calf part needs to be adjusted, the calf adjusting knob 3.4 can be rotated clockwise to loosen the adjusting main rod 3.5 and the extension adjusting seat 3.3, then the adjusting main rod 3.5 is pulled out to the corresponding length, and then the calf adjusting knob 3.4 is rotated counterclockwise to lock the adjusting main rod 3.5 and the extension adjusting seat 3.3, thereby completing the length adjustment of the calf part.

[0058] When the angle of the foot support 3.10 needs to be adjusted, the foot adjusting knob 3.6 can be rotated clockwise to loosen the adjusting main rod 3.5 and the foot support fixing seat 3.11, then the connection angle between the foot support fixing seat 3.11 and the adjusting main rod 3.5 is adjusted, and after adjustment is completed, the foot adjusting knob 3.6 is screwed into the corresponding bolt hole of the adjusting main rod 3.5 counterclockwise to lock the adjusting main rod 3.5 and the foot support fixing seat 3.11, thereby completing the angle adjustment of the foot support 3.10.

[0059] This invention provides an adjustable knee joint training device, which the user must use in a lying position. In use, the user's waist is first placed on the lumbar support mechanism 1, the thigh is fixed to the thigh mechanism 2, the lower leg is fixed to the lower leg and foot mechanism 3, and the foot is placed on the footrest 3.10. The motor 4 is then started, driving the driven gear 3.1 to rotate, simultaneously rotating the adjusting auxiliary rod 3.2, the telescopic adjusting seat 3.3, and the adjusting main rod 3.5. The rotation angle range is 50 degrees to 180 degrees. Through this reciprocating motion, flexion and extension rehabilitation exercises of the user's knee joint can be achieved.

[0060] Secondly, the present invention provides a control method for an adjustable knee joint training device.

[0061] like Figures 8-10 As shown, the present invention provides a control method for an adjustable knee joint training device, which achieves control of the knee joint training device based on gravity compensation, thereby enabling the knee joint training device to adapt to different lower leg lengths and overcome the torque generated by the device's own weight around the rotation axis.

[0062] like Figure 8 As shown, the lower leg and foot mechanism 3 is directly driven by the motor 4. The total mass of the lower leg and foot mechanism 3 and the motor 4 is m1, and the distance between the central axis of the output shaft of the motor 4 and the center of gravity of the lower leg and foot mechanism 3 is L1. The total mass of the thigh mechanism 2 is m2, and the distance between the central axis of the output shaft of the motor 4 and the center of gravity of the thigh mechanism 2 is L2.

[0063] like Figure 9 As shown, assuming the current rotation angle of the lower leg and foot mechanism 3 is θ (the angle between the axis of the lower leg and foot mechanism 3 and the horizontal plane), due to the linkage, there is a fixed geometric relationship between the rotation angle α of the thigh mechanism 2 (the angle between the axis of the thigh mechanism 2 and the horizontal plane) and the current rotation angle θ of the lower leg and foot mechanism 3: α = k·θ; where k is the linkage coefficient, which is determined by the length ratio of the lower leg and foot mechanism 3 to the thigh mechanism 2.

[0064] From this, we can deduce that:

[0065] The gravitational torque of the lower leg and foot mechanism 3: M1=m1·g·L1·cos(θ);

[0066] The gravitational torque of thigh mechanism 2: M2=m2·g·L2·cos(α)=m2·g·L2·cos(k·θ);

[0067] Total weight moment of force (the moment of force that the motor 4 needs to offset): Mtotal = M1 + M2 = m1 g L1 cos (θ) + m2 g L2 cos (kθ). Wherein, g is the acceleration of gravity.

[0068] The logic of the present application for compensating the moment of force generated by the weight of the device itself around the rotation axis is: the moment of force offset strategy for the linkage characteristics.

[0069] Specifically, in the moment of force offset strategy for the linkage characteristics, it is necessary to establish the relationship between the linkage angles. Since the motor 4 directly drives only the lower leg and foot mechanism 3, the rotation angle α of the thigh mechanism 2 needs to be derived through the mechanical structure geometry parameters: let the length of the lower leg and foot mechanism 3 be L 膝 , the length of the thigh mechanism 2 be L 髋 , then the linkage coefficient k = L 膝 / L 髋 (deduced from the trigonometric function relationship); the rotation angle α of the thigh mechanism 2 is calculated in real time through the current rotation angle θ of the lower leg and foot mechanism 3 and taken as an input parameter.

[0070] In summary, the control method of the adjustable knee joint training device provided by the present application includes the parameter calibration to the dynamic compensation process, and the specific implementation process is as follows:

[0071] Step S1: measurement of the mass and the center of gravity of the mechanical structure;

[0072] (1) The total mass of the lower leg and foot mechanism 3 and the motor 4 is measured by the weighing method, and the total mass of the thigh mechanism 2 is m1 and m2;

[0073] (2) The center of gravity positions of the lower leg and foot mechanism 3 and the thigh mechanism 2 are extracted by using the CAD model, and the distance L1 between the center axis of the output shaft of the motor 4 and the center of gravity of the lower leg and foot mechanism 3 and the distance L2 between the center axis of the output shaft of the motor 4 and the center of gravity of the thigh mechanism 2 are calculated.

[0074] Step S2: linkage coefficient k calibration;

[0075] The angle between the thigh mechanism 2 and the lower leg and foot mechanism 3 is manually driven from 180° (stretching) to 130° (flexion), and the actual rotation angle α of the thigh mechanism 2 is recorded, and k = α / θ is obtained by linear fitting (for example, θ = 60° and α = 30°, then k = 0.5).

[0076] Step S3: real-time compensation process (executed during movement);

[0077] Step S3.1: angle sensing;

[0078] The current rotation angle θ of the lower leg and foot mechanism 3 is collected in real time (sampling frequency ≥ 200 Hz) through an encoder arranged at the central axis of the output shaft of the motor 4.

[0079] Step S3.2: linkage angle and torque calculation;

[0080] According to α=k·θ, the total gravity torque of the device is calculated: Mtotal=m1·g·L1·cos(θ)+m2·g·L2·cos(k·θ).

[0081] Step S3.3: driving output and compensation implementation;

[0082] The calculated total gravity torque of the device, i.e. the compensation torque, is converted into a motor control signal, and the motor 4 is driven according to the motor control signal to output a corresponding torque according to the current rotation angle θ of the lower leg and foot mechanism 3 collected in real time, so as to compensate the gravity torque.

[0083] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the protection scope of the present application.

Claims

1. An adjustable knee joint training device, characterized in that, The utility model relates to a lumbar support mechanism, which comprises a thigh connecting seat fixed to the upper end of the shell connecting seat, a rotating limiting nut connected to the thigh connecting seat, an adjusting upper plate connected to the lumbar support mechanism through the rotating limiting nut, a plurality of evenly distributed limiting grooves provided on the adjusting upper plate, an adjusting lower plate slidably connected to the adjusting upper plate through two adjusting slide rails, an upper and lower plate connecting seat fixed to the adjusting lower plate, an adjusting lower pressing button installed on the upper and lower plate connecting seat, a button end cover, a limiting column and a limiting pin sequentially connected to the adjusting lower pressing button, the limiting pin being placed in the limiting groove on the adjusting upper plate, the lower end of the limiting column being in contact with the adjusting upper plate when the button end cover is pressed, and the limiting pin being unlocked by being separated from the limiting groove on the adjusting upper plate, a motor fixed to the adjusting lower plate, a lower leg and foot mechanism connected to the output end of the motor, a thigh limiting pin provided on the thigh connecting seat, a limiting pin mounting hole and a circular mounting hole provided on the upper end of the shell connecting seat, the limiting pin mounting hole being in communication with the circular mounting hole, the thigh limiting pin being installed in the limiting pin mounting hole, the head of the rotating limiting nut being semicircular in shape, a semicircular protrusion being provided on the upper side of the head of the rotating limiting nut, one end of the thigh limiting pin extending into the circular mounting hole from the limiting pin mounting hole, and the end of the extending end of the thigh limiting pin being clamped to the left side of the semicircular protrusion of the head of the rotating limiting nut, the rotating limiting nut being in a horizontal position at this time, and the thigh limiting pin being pushed upward by the shell connecting seat when the lumbar support mechanism is pushed upward. The rotating limiting nut, the adjusting upper plate, the adjusting lower pressing button, the upper and lower plate connecting seat, the adjusting lower plate and the two adjusting slide rails are installed in the thigh mechanism shell. Two strip-shaped holes are provided on the adjusting upper plate, the two adjusting slide rails are installed in the two strip-shaped holes respectively, and the adjusting upper plate and the adjusting lower plate are slidably connected. The upper and lower plate connecting seat is in the shape of a U, and the adjusting upper plate passes through the lower part of the U-shaped upper and lower plate connecting seat. The lower leg and foot mechanism comprises a motor driven gear installed on the output shaft of the motor, an adjusting secondary lever connected to the motor driven gear, an extension adjusting seat connected to the adjusting secondary lever, an adjusting main lever connected to the extension adjusting seat through a lower leg adjusting knob, a foot support fixing seat connected to the adjusting main lever through a foot adjusting knob, and a foot support fixed to the foot support fixing seat. The foot support fixing seat is in the shape of a U, the foot support is fixed in the U-shaped foot support fixing seat, the lower end of the adjusting main lever is provided with a plurality of evenly distributed bolt holes, the foot adjusting knob is screwed into the corresponding bolt hole, and the adjusting main lever and the foot support fixing seat are connected and fixed through the foot adjusting knob. The lower leg and foot mechanism further comprises a caster connecting shaft installed at the lower end of the foot support fixing seat and two casters installed at the two ends of the caster connecting shaft respectively. The following steps are included: ​ ​ 2. An adjustable knee joint exercise device according to claim 1, wherein, ​ 3. An adjustable knee joint exercise device according to claim 1, wherein, ​ 4. An adjustable knee joint exercise device according to claim 1, wherein, ​ 5. An adjustable knee joint exercise device as defined in claim 1, wherein, ​ 6. An adjustable knee joint exercise device according to claim 5, wherein, ​ 7. An adjustable knee joint exercise device according to claim 5, wherein, ​ 8. A method of controlling an adjustable knee joint training device according to any one of claims 1-7, characterized in that, ​ Step S1: The total mass of the lower leg and foot mechanism and the motor is measured by weighing method, which is m1, and the total mass of the thigh mechanism is m2; the center of gravity position of the lower leg and foot mechanism and the center of gravity position of the thigh mechanism are extracted by using CAD model, and the distance L1 between the center axis of the motor output shaft and the center of gravity of the lower leg and foot mechanism and the distance L2 between the center axis of the motor output shaft and the center of gravity of the thigh mechanism are calculated; Step S2: The angle between the thigh mechanism and the lower leg and foot mechanism is manually driven from 180° to 130°, and the actual rotation angle α of the thigh mechanism is recorded, and the linkage coefficient k = α / θ is obtained by linear fitting; Step S3: Real-time compensation process is performed during movement; The current rotation angle θ of the lower leg and foot mechanism is collected in real time by the encoder arranged at the center axis of the motor output shaft; the total gravity torque of the device is calculated: Mtotal = m1·g·L1·cos(θ) + m2·g·L2·cos(k·θ), g is the acceleration of gravity; the total gravity torque of the device is converted into a motor control signal, and the motor outputs a corresponding torque according to the current rotation angle θ of the lower leg and foot mechanism collected in real time to compensate the gravity torque.

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