KR101841477B1 - Lower limb rehabilitation robot system based on wire driven actuator and method of controlling the same - Google Patents

Abstract

A wire-driven based rehabilitation device and its control method are disclosed. The disclosed underarm rehabilitation apparatus includes a tread mill; An end effector fixed to a body part of a patient, a plurality of motors rotating forward and reverse so as to wind or loosen a plurality of wires connected to the end effector; And calculating a difference between a gait locus of the patient and a predetermined gait locus calculated through a tension on the plurality of wires in accordance with the movement of the end effector when the patient is walking on the treadmill, And a control unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire driving based rehabilitation apparatus and a control method thereof,

[0001] The present invention relates to a wire-driven based rehabilitation apparatus and a control method thereof for helping a person to walk, and more particularly, Based rehabilitation apparatus and its control method that can be used for rehabilitation of lower limbs.

BACKGROUND ART [0002] With the development of control systems in the field of industrial machinery control, development of robots driven by the control signals of these control systems is also active. Recently, cable-based parallel type robot, which is a new type of robot, has appeared due to the development of control technology. The link, which is the structure of each part of the conventional serial robot, requires a large number of actuators because the motor must be mounted for each joint, and the overall system is heavy. Also, the control signal that manipulates this complexity caused many errors. This means that the working efficiency is lowered. On the other hand, the wire-driven parallel type robot can replace the existing link with a wire and attach the driver to the ground. It is possible to use a small actuator and it is possible to operate the robot with a relatively simple control signal.

Further, since there is no complicated configuration, a large working space can be ensured and a heavy load can be carried. Further, since the movement of the robot is quick, the working time is shortened, and the configuration required for the robot system can be minimized, it is advantageous in that it can be made compact and low in cost.

Such wire-driven parallel robots have been used for aerodynamic aerodromes and amusement devices since the past, due to the multi-degree-of-freedom and robustness of the parallel mechanism. In addition, it can be used in various applications such as industry, play, environment, etc., and is a robot having a very high potential. Currently, paint robots are used to paint vessels in particular, cleaning robots to clean the outer walls and windows of buildings, and crane robots to transport heavy objects. In addition, the cable-driven parallel robot is the same type as the wire-driven parallel robot. In the cable park in Korea, there is a place where water sports can be enjoyed using an ear cable structure. And operating. In the environmental field, water quality inspection cable robots have been developed which can inspect and manage water quality such as rivers, lakes, and seas.

The cable-driven parallel robot consists of a frame that determines the working space of the robot, a winch system installed in the frame to adjust the cable length, and a work tool to which the cable from the winch is connected. And a pulley that is installed between the tools to allow the cable to exit at various positions and heights.

On the other hand, rehabilitation is the treatment of abnormal patterns in people with physical (musculoskeletal, circulatory, neurological), mental and emotional disorders due to any disease, accident or internal or external damage, To recover or enhance the normal pattern. Particularly in the case of persons with disabilities, rehabilitation training requires comprehensive help from experts in various fields, and it is necessary to perform repetitive and systematic rehabilitation.

And mediation of the patient 's activities and movements is done by applying external forces. Conventionally, a serial robot has been used in which a link is attached to a leg of a patient to follow the correct walking provided by the robot in order to apply such external force. However, there was a disadvantage that the efficiency of rehabilitation was inferior due to the fact that the patient could easily lose his will and interest in rehabilitation by eliminating the power of the patient and providing only blind rehabilitation. In addition, since the driver is attached to each link joint and the size of the actuator is increased due to the need of large power, the whole system is heavy and it is not easy for the patient to wear the robot. A typical serial robotic rehabilitation device is Hokoma's Lokomat®. This is accomplished by wearing a serial robot composed of links on a tread mill. However, according to the clinical application results, the efficiency is similar or lower than that of traditional gait rehabilitation. This is because the patient's adaptation to the gait pattern produced by the link loses will and interest in rehabilitation, and there are many differences from the actual walking in that the pelvic and knee movements are restricted in the sagital plane. In addition, heavy and complicated systems and high prices have made barriers to entry for consumers.

In addition, even when an external force is provided using the cable or wire-driven robot, an end effector directly attached to the body of the patient can not follow the speed of the wire, If the correct walking pattern is deviated, the wire is loosened. At this time, there is a fear that the wire is released from the pulley and is caught by the other part, thereby breaking the wire, and the robot operates abnormally, which may cause a risk to a pedestrian using the wire-driven robot.

Korean Patent No. 10-1566680 is a parallel-type robot based on a cable drive, but it is disadvantageous in that a water tank for underwater rehabilitation is required, which is expensive and the entire system becomes heavy. Also, there is a drawback that the cable can not be prevented from loosening.

Therefore, a rehabilitation robot which can be applied to actual rehabilitation exercise with small size, light weight and low cost, and which provides only the minimum force necessary for the patient with the wire, can enhance the rehabilitation of the patient and increase the rehabilitation efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a rehabilitation apparatus for a footrest that can follow a correct gait pattern by controlling a calf of a patient through four or more wires .

Another object of the present invention is to provide a rehabilitation apparatus for a lower limb which is constructed of a parallel robot and can be quickly and accurately driven even with a small-capacity driver.

Another object of the present invention is to provide an underarm rehabilitation device capable of suppressing a negative tension by grasping an active gait pattern of a patient and providing only a minimum force necessary for a patient, thereby preventing a wire from being loosened I have to.

Another object of the present invention is to provide a control method of a lower limb rehabilitation apparatus for nonlinear element control so that negative tension is not generated on a wire used in a lower limb rehabilitation apparatus.

In order to accomplish the above object, the present invention relates to a tread mill; An end effector secured to the body part of the patient; A plurality of motors rotating forward and backward to wind or loosen a plurality of wires connected to the end effector; And calculating a difference between a gait locus of the patient and a predetermined gait locus calculated through the tension on the plurality of wires in accordance with the movement of the end effector when the patient is walking on the treadmill, And a controller for controlling the rehabilitation device.

The invention relates to a front and rear frame of the treadmill; A plurality of pulleys disposed in the front and rear frames to guide the wires; And an information receiving unit coupled to each of the motors to sense a tension of each of the wires. And a display unit for outputting information about the tension and a result of calculating a difference between the two walking trajectories.

The control unit may use a computed torque method for controlling the non-linear elements to suppress the negative tension when generating the control signal for driving the plurality of motors.

The end effector may be configured to be secured to at least two of the body parts of the patient.

The present invention is characterized by a slider slidably coupled to the front frame, the slider having the plurality of pulleys rotatably connected thereto; And a linear actuator for driving the slider. In this case, when generating the control signal for driving the plurality of motors, the control unit may use a computed torque method for controlling non-linear elements to suppress negative tension.

The control unit generates an additional control signal for driving the linear driver and generates a control signal for driving the linear driver by using a computed torque to suppress a negative tension by excluding a non- method can be used.

In order to achieve the above object, the present invention also provides a method of operating a treadmill, comprising: (a) moving an end effector mounted by a patient as the patient starts walking on a treadmill; (B) receiving information about a tension on a wire connected to the end effector according to a walking speed of a patient and detecting an actual walking trajectory of the patient; (C) calculating an error by comparing a preset gait locus and an actual gait locus of the patient; And (d) controlling a plurality of motors connected to each wire to rotate forward or reverse, so as to adjust a tension of the wire by a difference according to the error by winding or unwinding the wire. .

The method of claim 1, further comprising: (e) before the step (c), converting information about the received tension into kinematic information, wherein the kinematic information is position information that can be specified in two- It can show the trajectory.

The step (e) may control non-linear elements generated while converting the received information into kinetic information.

The step (e) may further include the step of (f) outputting the kinematical information converted into the two-dimensional phase coordinate to the display unit.

The step (c) may further include a step (g) of comparing the two trajectories and outputting a result of calculating an error to the display unit.

In the step (d), the position coordinate information according to the error between the two walking trajectories is converted into a control signal for controlling the motor, thereby suppressing nonlinear elements and generating a control signal according to the error.

(D) generating an additional control signal for controlling a preceding driver that varies the position of the pulley so as to adjust the tension of the wire; The non-linear elements can be suppressed while generating the additional control signal.

As described above, the structure of the present invention is simple, easy to install and disassemble, is light, and is effective in improving rehabilitation efficiency at low cost. In addition, the present invention is human-friendly in that it provides an optimum gait pattern to a patient by installing a device capable of constantly grasping the patient's condition, thereby stimulating the patient's will to rehabilitate.

 Further, the present invention can provide a patient-initiated rehabilitation mode as an advanced technology in which mechatronics technology and medical technology are fused based on a biofeedback-based gait control technique.

1 is a side view schematically showing a structure of a lower limb rehabilitation apparatus according to a first embodiment of the present invention.
FIG. 2 is a view showing the use state of the underwear rehabilitation apparatus according to the first embodiment of the present invention.
FIG. 3 is a view showing the use state of the underwear rehabilitation apparatus according to the second embodiment of the present invention.
4 is a side view schematically showing a structure of a lower limb rehabilitation apparatus according to a third embodiment of the present invention.
FIG. 5 is a view showing the use state of the underwear rehabilitation apparatus according to the third embodiment of the present invention.
FIG. 6 is a view showing the use state of the underwear rehabilitation apparatus according to the fourth embodiment of the present invention.
7 is a perspective view illustrating a structure of an end effector according to an embodiment of the present invention.
8 is a block diagram showing an overall system configuration of a lower limb rehabilitation apparatus according to an embodiment of the present invention.
9 is a flowchart illustrating a method for suppressing negative tension generated in a wire according to an embodiment of the present invention.
FIG. 10 is a block diagram of an optimized under-rehabilitation apparatus according to a computerized torque calculation method (CTM) according to an embodiment of the present invention.
FIG. 11 is a graphical representation of an optimized rehabilitation apparatus according to a computerized torque calculation method (CTM) according to an embodiment of the present invention.
FIG. 12 is a view showing a locus generated by an end effector according to an embodiment of the present invention.
13 is a graph showing a force and a tension of a wire required for a linear actuator according to an embodiment of the present invention.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings and the following detailed description. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided by way of illustration to those skilled in the art to which the present invention pertains. Like reference numerals designate like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Also, in this specification, the singular form includes plural forms unless specifically stated in the phrase. &Quot; comprise "or" comprising "when used in this specification do not preclude the presence or addition of one or more other elements, steps, operations, or elements .

Hereinafter, with reference to Figs. 1 to 6, a description will be made in detail of a lower limb rehabilitation apparatus according to an embodiment of the present invention.

The rehabilitation apparatus 100 according to an embodiment of the present invention includes a wire driven parallel robot for gait rehabilitation, a cable driven parallel robot for gait rehabilitation).

FIG. 1 is a side view schematically showing a structure of a lower limb rehabilitation apparatus according to a first embodiment of the present invention, and FIG. 2 is a view showing a use state of a lower limb rehabilitation apparatus according to the first embodiment of the present invention.

1 and 2, the underwear rehabilitation apparatus 100 includes a tread mill 10, an end effector 170, a plurality of motors 110, 111, and 112 113), and a control unit 150 for generating control signals for controlling the driving of a plurality of motors.

The tread mill 10 does not limit the belt 10 in any way as long as the belt on which the patient can walk has an infinite orbit and can secure a space necessary for walking.

The plurality of motors 110 are disposed to be positioned at the lower end portions of the front and rear of the tread mill 10. In this case, the plurality of motors 110, 111, 112, and 113 may be disposed on the ground, but preferably, the motor supports 101 and 102 are provided on the front and rear of the tread mill 10, As shown in FIG.

The rehabilitation apparatus 100 is provided with a drum 110 capable of winding and unwinding a plurality of wires 11 connected to the respective motors 110, 111, 112 and 113 by receiving a rotational force from a plurality of motors 110, 111, 112, (103) and a guide unit (104) for guiding the wire (11) to be constantly wound on the drum.

The plurality of motors 110, 111, 112, and 113 may be disposed at least two in front of and behind the tread mill 10, respectively.

The controller 150 is electrically connected to the plurality of driving motors 110, 111, 112 and 113 and the display unit 160, respectively. The control unit 150 generates a control signal for driving the plurality of motors 110, 111, 112, and 113 to rotate forward or backward to adjust the length and speed of the wire 11 wound or unwound.

The control unit 150 may convert a predetermined walking trajectory into a control signal for driving the plurality of motors 110, 111, 112, and 113.

In the process of converting the control signal, a computed torque method (CTM) and a proportional-differentional controller may be used.

2, the underwear rehabilitation apparatus 100 may include a plurality of frames 120, 121, 122, and 123 installed around the treadmill 10.

The plurality of frames 120, 121, 122, 123 may be composed of the front frames 120, 121 and the rear frames 122, 123. It is also possible to further include separate handle frames 124 and 125 that connect the front frames 120 and 121 and the rear frames 122 and 123 and that function to hold the patient while holding him / have.

At least two front pulleys 130 and 131 may be disposed on the front frames 120 and 121 at predetermined intervals in the vertical direction. In this case, the front pulleys 130 and 131 may be rotatably mounted on two front supporting rods 126 and 127 fixed to both ends of the pair of front frames 120 and 121, respectively. At least two rear pulleys 132 and 133 may be disposed on the rear frames 122 and 123 at predetermined vertical and vertical intervals. In this case, the rear pulleys 132 and 133 can be rotatably installed on the two rear support rods 128 and 129 fixed to both ends of the pair of front frames 122 and 123, respectively.

The front and rear pulleys 130, 131, 132 and 133 guide the directions of the plurality of wires 11 wound by the motors 110, 111, 112 and 113, respectively.

The end effector 170 is connected to the plurality of wires 11 and can be fixed to a body part of a patient, for example, a calf who wants to rehabilitate. In this case, to fix the end effector 170 to the body part, it may be attached to the body part or may be formed so as to surround the body part. In the present embodiment, it is described that the end effector 170 is configured to be worn on the calf of the patient. The end effector 170 is connected to a plurality of motors 110 through a plurality of wires 11 so that when the patient walks on the treadmill 10 after wearing the respective motors 110, 111, 112, 113 can be used as an element for grasping a patient's gait pattern necessary for rehabilitation by the movement of the wire 11. [

The end effector 170 covers the calf portion of the patient and each wire 11 is wound or unwound by driving the motors 110, 111, 112, and 113, A constant force is applied to the part of the calf of the patient to induce and assist the walking.

In addition, the underground rehabilitation apparatus 100 may further include a plurality of information receiving units 140, 141, 142, and 143. The plurality of information receiving units 140, 141, 142, and 143 acquire information on the status of the patient. The information may include all patient information that can be input through the sensor, such as the walking speed of the patient, the magnitude of the force applied by the patient, and the tension applied to the wire 11. [ The plurality of information receiving units 140, 141, 142, and 143 may be located at the ends of the motors 110, 111, 112, and 113 and may acquire information about the tension applied to the wires 11 .

The control unit 150 is connected to the plurality of information receiving units 140, 141, 142 and 143 and generates a walking trajectory of the patient based on the information obtained from the plurality of information receiving units 140, 141, 142, Can be calculated.

The controller 150 compares the calculated gait trajectory of the patient with a preset gait trajectory and calculates the difference value. And generates a control signal for controlling the plurality of motors 110, 111, 112, and 113 based on the difference value.

The control unit 150 controls the nonlinear elements to generate a negative tension on the wires 11 when the control signals for driving the motors 110, 111, 112, and 113 are generated, A computed torque method (CTM) can be used.

In addition, the underground rehabilitation apparatus 100 includes a display unit 160 for outputting information about the tension and a result of calculating a difference between the two walking trajectories (a walking trajectory of the patient and a predetermined walking trajectory) .

The display unit 160 may be installed on the controller 150 or may be separately installed and connected to the controller 150.

The display unit 160 may output information such as the walking speed of the patient, the tension generated in the wire, the force applied by the patient, the difference between the preset walking trajectory and the patient's walking trajectory. Thus, through the display unit 160, the rehabilitation instructor can continuously monitor whether the patient forms a correct walking trajectory, and can transmit the walking state to the patient so as to correct the walking posture of the patient in real time .

FIG. 3 is a view showing the use state of the underwear rehabilitation apparatus according to the second embodiment of the present invention. The illustration of each wire 11 is omitted for clarifying the configuration of the underarm rehabilitation apparatus 200. [ Also, illustration of the control unit 150 and the display unit 160 is omitted.

The end effector, the motor, the pulley, and the information receiving unit are configured to have a configuration for applying two end effectors to the rehabilitation apparatus 200 according to the second embodiment of the present invention, .

And includes a tread mill 20, front and rear frames 120, 121, 122 and 123, a control unit 150 and a display unit 160 as in the first embodiment described above.

The lower limb rehabilitation apparatus according to the second embodiment further includes additional pulleys 234, 235, 236, 237 and a plurality of motors 214, 215, 216, 217 in the tread mill 20.

The end effector 170 also includes an additional end effector 271 to be worn on another calf of the patient.

In addition, the two end effectors 170, 271 may contact or be wrapped around both calves of the patient to assist in the walking of both legs of the patient.

An additional information receiving unit may be coupled to the plurality of motors 214, 215, 216, and 217. The additional information receiving unit may receive information on the tension of the wire connected to both legs together with the existing information receiving units 140, 141, 142, and 143. [

The received information is processed in the control unit 150 as in the first embodiment described above.

FIG. 4 is a side view schematically showing the structure of a lower limb rehabilitation apparatus according to a third embodiment of the present invention, and FIG. 5 is a view illustrating a use state of the lower limb rehabilitation apparatus according to the third embodiment of the present invention. 4 and 5, the illustration of the control unit 150 and the display unit 160 is omitted in order to clarify the differentiated configuration of the lower limb rehabilitation apparatus according to the third embodiment of the present invention.

In describing the configuration of the third embodiment, a detailed description of the same configurations as those of the above-described embodiment will be omitted, and only the slider 380 and the linear actuator 390 having different configurations will be described.

5, the linear driver 390 includes at least two linear actuators 390 and may be coupled to the front frames 320 and 321. The linear actuator 390 is configured to face the same axis as the front frames 320 and 321.

The two linear actuators 390 and 391 include two sliders 380 and 381 for allowing the pulleys 330 and 331 to slide in the vertical direction and the two sliders 380 and 381 coupled to the sliders 380 and 381, The pulleys 330 and 331 may be slid to a predetermined position.

The two linear actuators 390 and 391 may be connected to the front motors 310 and 311 and / or the control unit 150 and may receive control signals from the front motors 310 and 311 and / .

The control unit 150 may generate an additional control signal for driving the linear drivers 390 and 391 in addition to the control signals for driving the front and rear motors 310, 311, 312 and 313. [

When the control unit 150 generates a control signal for driving the linear drivers 390 and 391, the controller 150 controls the nonlinear elements to generate a negative tension on the wire 33 A computed torque method can be used.

When the front motors 310 and 311 send control signals to the two linear actuators 390 and 391, the front motors 310 and 311 control the linear actuators 390 and 391 And transmits the generated control signal to the linear drivers 390 and 391.

The two linear actuators 390 and 391 receive the control signal sent from the controller 150 and adjust the position of the slider coupled to the pulleys 330 and 331 in order to provide an optimal walking trajectory 380, and 381) can be continuously slid up and down.

As the sliders 380 and 381 coupled with the pulleys 330 and 331 slide up and down, the plurality of motors 310, 311, 312, and 313 interlock with each other to wind or unwind the wire 33, (end effector, 370) to create an optimal gait trajectory.

Information such as a state in which the two linear actuators 390 and 391 are driven and a force necessary for driving can be output to the display unit 160. [

The display unit 160 may output a value calculated by summing the tension generated in the wire and the force required for the linear actuators 390 and 391.

In this case, the driving force required to cause the end effector 370 to form an optimal gait trajectory can be minimized, and compared to other embodiments of the present invention, a motor having a relatively low output The above-described under-rehabilitation apparatus can be constituted.

FIG. 6 is a view showing the use state of the underwear rehabilitation apparatus according to the fourth embodiment of the present invention. The illustration of each wire 33 is omitted in order to clarify the configuration of the rehabilitation apparatus 400. In FIG. 6, the illustration of the control unit 150 and the display unit 160 is omitted.

The end effector, the motor, the pulley, and the information receiving unit are configured to have a configuration for applying two end effectors to the rehabilitation apparatus 400 according to the fourth embodiment of the present invention, .

The lower limb rehabilitation apparatus according to the fourth embodiment of the present invention includes the tread mill 40, the front and rear frames 320, 321, 322 and 323, the control unit 150, the display unit 160 And sliders 380 and 381 linear actuators 390 and 391, respectively.

The lower limb rehabilitation apparatus according to the fourth embodiment further includes additional pulleys 434, 435, 436 and 437 and a plurality of motors 414, 415, 416 and 417 in the tread mill 40.

The end effector 370 also includes an additional end effector 471 to be worn on the other calf of the patient.

In addition, the two end effectors 370, 471 may be contacted or wrapped around both calves of the patient to assist in the walking of both legs of the patient.

Additional information receiving units may be coupled to the plurality of motors 414, 415, 416, and 417. The additional information receiving unit may receive information on the tension of the wire connected to both legs together with the existing information receiving units 340, 341, 342, and 343.

The received information is processed in the control unit 150 as in the third embodiment described above.

The control unit 150 may generate an additional control signal for driving the linear drivers 390 and 391 in addition to the control signals for driving the front and rear motors 310 to 313 and 414 to 417.

When the control unit 150 generates a control signal for driving the linear drivers 390 and 391, the controller 150 controls the nonlinear elements to generate a negative tension on the wire 33 A computed torque method can be used.

The control unit 150 may generate and transmit control signals for driving the motors 310 to 313 and 414 to 417 and the linear drivers 390 and 391.

The two linear actuators 390 and 391 may be connected to the front motors 310, 311, 414 and 415 and / or the control unit 150 and may be connected to the front motors 310, 311, 414 and 415 and / 150). ≪ / RTI >

Fig. 7 shows an end effector 170 used in the above-described underwear rehabilitation apparatus. The end effector 170 includes a support portion 171 and a fixed belt 172. However, there is no limitation to the shape of the support portion 171, and it is sufficient that the shape of the support portion 171 can be contacted or wrapped around the calf.

Hereinafter, a method of suppressing negative tension generated in a wire according to an embodiment of the present invention will be described in detail with reference to FIGS. 8 to 13. FIG.

FIG. 8 is a block diagram illustrating an overall system configuration of a lower limb rehabilitation apparatus according to an embodiment of the present invention. FIG. 9 illustrates a method for suppressing negative tension generated in a wire according to an embodiment of the present invention FIG.

First, the patient wears the end effector 170 and starts walking on the treadmill 10. The end effector 170 mounted on the calf of the patient follows the walking trajectory of the patient accordingly (S1110).

As the end effector 170 is driven, tensile forces are generated on the plurality of wires 11, and the tension is sensed by the information receiving unit 140 (S1120).

The information about the tension obtained by the information receiving unit 140 is converted into coordinate position information represented by two-dimensional coordinates in the kinematic information converting unit 151 (S1130). The converted information is transmitted to the controller 150.

The converting unit 151 for converting the tension information into kinematic information may be implemented by a central processing unit and integrated with the control unit 150. [

In the process of converting information in the converting unit 151, a computed torque method is used to control the nonlinear element (S1140).

The converted coordinate position information may be output to the display unit 160 (S1141).

In step S1150, the control unit 150 compares the difference between the actual trajectory of the patient converted into the coordinates on the basis of the trajectory created according to the preset coordinates and the received information.

The difference due to the comparison between the two trajectories can be defined as an error value.

In addition, the error value may be further output to the display unit 160 (S1151). This allows the user or the patient to visually grasp the gait pattern and the rehabilitation therapist can continuously monitor the state of the user or the patient.

The control unit 150 forms a control signal for driving the motor 110 according to the error value (S1170).

In operation S1160, the controller 150 controls the nonlinear element and uses the computed torque method to suppress the negative tension generated in the wire.

When forming the control signal, the control unit 150 may form an additional control signal for driving the linear driver 390 (S1171).

Then, the control signal is transmitted to the motor 110 (S1180).

The additional control signal is transmitted to the motor 110 or the linear driver 390. When the additional control signal is transmitted to the motor 110, the motor 110 relays it to the linear driver 390.

The motor 110 or the linear actuator 390 receiving the control signal drives the end effector 170 of the underarm rehabilitation apparatus 100 to induce the patient to walk (S1190).

10 and 11 are diagrams showing a system configuration diagram and a mathematical analysis for designing a computerized torque calculation method used for suppressing a negative tension generated in a wire.

Referring to FIGS. 10 and 11, in the wire driven parallel robot, the design process of the computerized torque calculation logic used to suppress the negative tension is as follows.

First, the relationship between the pose of the end effector and the controllable wrench structure becomes a fundamental problem. This relationship is called a wrench-closure configuration, and the application of tension to a plurality of wires is called a wrench. That is, it can be defined as a set of posture of the end effector produced by the tension of the wire.

Particularly, in the underarm rehabilitation equipment according to the present invention, the end effector is attached to the calf of the patient. At this time, the angle of the calf in the sagittal plane determines the posture of the end effector.

However, since the radius at which the calf can be rotated by a person's knee is limited, complete control of the end effector is required to maintain a stable calf angle of the patient.

In this case, controlling all the degrees of freedom (DOF) of the end effector is substantially related to the number of wires used in the end effector and the number of degrees of freedom with which the end effector can move. If the number of wires is less than the number of degrees of freedom, the sum of the moments due to the tension of the wire will be negative on one or more wires connected to the end effector.

An optimized configuration for excluding such negative values is shown in FIG.

At the sagittal, we use four wires to control the three degrees of freedom of the end effector.

In particular, it is assumed that the front two pulleys A1 and A2 for controlling the tension of the wire are mounted on the linear actuator and can move up and down together with the end effector instead of being fixed to the ground.

The wrench-closure configuration consists of two parts, a platform on which the above configuration is installed and a linear actuator, and the dynamics of the two parts should be considered.

To this end, a map between the reference coordinate space and the driver coordinates is set, and the wrench, which is the tension of the wire obtained by the control unit for each step, must be mapped from the reference coordinate space to the coordinates at which the wire should be located .

And we will derive the dynamic equation considering the dynamics of the two parts. However, it is difficult to construct the control logic fundamentally because a nonlinear term is generated.

Therefore, the effect of the nonlinear term is canceled by the computerized torque calculation method, and the tension required for the wire and the control signal value for the driving force of the linear actuator are found. And will use a Proportional Differential (PD) control to make the error zero.

FIG. 11 is a mathematically analyzed diagram for deriving such a computerized torque calculation method.

It is assumed that the end effector separated from the calf is the calf of the human body.

는 각각 와이어의 순서를 나타낸다.

Respectively denote the order of the wires.

는 와이어가 엔드 이펙터에 부착된 점을 말한다.

Refers to the point where the wire is attached to the end effector.

에 있다고 가정하였으며, 이 Wrench-closure configuration에서 전방에 설치된 A1, A2 풀리는 수직 방향으로 슬라이딩이 가능하도록 슬라이더와 결합되어 선형 구동기에 구동된다고 가정하였다.And four motors

In this Wrench-closure configuration, it is assumed that the A1 and A2 pulleys installed at the front are connected to the slider so that they can be slid in the vertical direction and driven by the linear actuator.

Therefore, the position of the two pulleys in the y direction can be expressed as follows.

Then, coordinate axes are defined as X and Y based on point O, and U and V are defined as unit vector based on point G.

이고, 항상

이다. The length of the wire is

And always

to be.

로 표기된다.The position of the end effector is defined as the start point of the point O. When the end point of the end effector is defined as the end point,

Respectively.

로 정의된다.The azimuth between the X-axis and the U-

.

If you make this assumption, the following formula is derived.

의 위치 벡터는

이 된다.At this time

The position vector of

.

This time, let's assume that the platform of the Wrench-closure configuration works on a sagittal basis for static modeling.

이라고 할 때, 토크는 점 G에 적용이 된다. In this case, the plane tension of the wire

, The torque is applied to the point G.

라고 하면, 좌표 상에서는

로 나타낼 수 있다.Then, the Plucker Vector of the i-th wire

In terms of coordinates,

.

이고, 여기서

는 와이어의 장력을 나타내는 양수 값이 된다. And, the tension applied by the ith wire is

, Where

Becomes a positive value indicating the tension of the wire.

가 전체 와이어 장력의 합에 의해 균형을 이룬다고 가정하면, 다음과 같은 수학식 1이 도출된다.If tension

Is balanced by the sum of the total wire tensions, the following equation (1) is derived.

(1)

J is a 3 * 4 matrix, and changes depending on the position and orientation of the end effector and the position of the linear actuator on the Z axis in Fig.

Next, the relationship between the end effector and the Z-axis position of the linear actuator in Fig. 11 is expressed by a kinetic equation. For this, the mass of the wire is reported as zero and the kinematics of the pulley is not considered. In this case, the relationship between the end-effector and the position on the Z-axis of the linear actuator can be expressed by the following equations (2) and (3), which are multidimensional differential equations.

(2)

(3)

m and I represent the mass and inertia of the end effector, respectively.

는 플랫폼의 위치와 방위를 포함하는 엔드 이펙터의 상태 변수이다.

Is an end-effector state variable that includes the position and orientation of the platform.

,

는 X축과 Y축 방향으로 엔드 이펙터에 가해진 합력을 나타낸다. 그리고

는 엔드 이펙터의 합성 모멘트를 나타낸다. 또한,

는 선형 구동기의 질량을 나타낸다. Z는 선형 구동기의 수직 방향 위치를 나타내며, c는 마찰 계수를 의미한다.

,

Represents the resultant force applied to the end effector in the X-axis and Y-axis directions. And

Represents the composite moment of the end effector. Also,

Represents the mass of the linear actuator. Z represents the vertical position of the linear actuator, and c represents the coefficient of friction.

통해, 상기 수학식 2 및 3을 행렬 꼴로 나타내면 다음의 수학식 4 및 5와 같다.The following expression

The above equations (2) and (3) can be represented by the following mathematical formulas (4) and (5).

(4)

(5)

Alternatively, it may be simplified as shown in Equations (6) and (7) below.

(6)

(7)

Now, based on the above derived equations, a computed torque method and a proportional differential control can be designed as control logic.

In Equation (6), N includes all non-linear terms.

Therefore, when constructing the CTM, the differential equation becomes the second-order linear equation, and the control logic can be defined as the following Equation (8).

(8)

는 상태 백터

의 미리 설정된 또는 원하는(desired) 궤적을 나타내고, 에러는

로 나타낼 수 있다. here,

The state vector

The desired trajectory of < RTI ID = 0.0 >

.

,

는 대각위(diagonal position)행렬로 선택된 이득 행렬이다. Also,

,

Is a gain matrix selected as a diagonal position matrix.

로부터 와이어의 장력과 선형 구동기의 힘을 계산할 필요가 있다. 그러나 와이어 구동 기반 병렬형 로봇에서 양의 장력을 유지하는 것이 효과적인 제어 알고리즘을 위해 중요한 사항이라는 점을 고려할때, 선형 구동기와 엔드 이펙터에 대한 각각의 동역학을 고려하여 와이어의 장력을 양의 값으로 유지시키는 방법을 취할 수 있다. The tension in equation (8)

It is necessary to calculate the tension of the wire and the force of the linear actuator. However, considering that maintaining positive tension in wire-driven parallel robots is an important issue for effective control algorithms, it is important to keep the tension of the wire positive by taking into account the respective dynamics of the linear actuator and the end effector. Can be taken.

가 두 부분으로 분리될 수 있음을 알 수 있다.In Equation (4)

Can be separated into two parts.

는 수학식 3의 오른쪽 편 항과 같다. 수학식 1에서 엔드 이펙터에 가해진 장력

은 J행렬에 의한 와이어의 장력과 관련이 있다. 이 행렬은 정방행렬이 아니므로

에 따른 와이어의 장력은 계산될 수 없고, 무수히 많은 해가 주어진다. here

Is the same as the right-hand side of the equation (3). The tension applied to the end effector in Equation (1)

Is related to the tension of the wire by the J matrix. Since this matrix is not a square matrix

The tension of the wire can not be calculated, and a myriad of solutions are given.

The solution is as follows.

로 계산되는

는 특이해 이다. n은 J의 null space의 행렬이고,

는 임의의 상수이다. here

Calculated by

Is unusual. n is a matrix of null spaces of J,

Is an arbitrary constant.

가 특이해임에도 불구하고 상수

는 모든 와이어에서 양의 장력을 가지거나, 각 와이어의 장력이 구체화된 최소 장력

보다 크도록 할 수 있다.From this relationship, if all elements of the null vector n have the same sign,

Is unusual, but constant

May have a positive tension on all wires, or a minimum tension

.

의 모든 요소와 n에서 적절한 요소를 위해,

는

로 계산된다.

는 위의 구성요소 부호에 의해 곱해진

의 최고 값으로 결정된다. 벡터 n은 행렬 J의 null space로서 부호가 어떠한 구성을 가지느냐에 따라 변한다.Therefore,

For every element of n and for the appropriate element in n,

The

.

Is multiplied by the above component sign

As shown in FIG. The vector n is a null space of the matrix J, which varies depending on how the sign has some configuration.

And if it consists of only vector n with the same sign, it is defined as Wrench closure configuration.

경우, 최소 하나의 벡터는

를 만족시킨다.In other words,

At least one vector is

.

11 shows a wire-driven parallel type robot that satisfies the conditions of a wrench closure configuration by a linear actuator.

The force required to drive the linear actuator is also derived from equation (5).

Therefore, by computerized torque calculation, the tension of the wire and the force of the linear actuator are calculated and applied, so that the motor and the linear actuator are controlled so that the end effector can move with the optimum trajectory.

The position of the end effector can be grasped by measuring the tension of the wire by regular guidance using an information receiving unit, preferably an encoder, in the motor.

으로 가정하였고, 선형 구동기는

로 가정하였다.When designing the computerized torque calculation method, kinematics was considered on the basis of an adult male calf. The mass and inertia of the calf are

, And the linear actuator

Respectively.

The inertia and rotational damping coefficient of the pulley are not considered.

The algorithm of the control part was set by the computerized torque calculation method designed as above and the nonlinear element was controlled by implementing the Metlab code. The optimized walking trajectory is thus disclosed in Fig.

FIG. 13 also graphically shows the tension of the wire and the force required for the linear actuator to satisfy the wrench closure configuration condition. As shown in FIG. 13, it can be seen that all the wires follow the trajectory with a positive tension without loosening due to no negative tension.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by all changes or modifications derived from the scope of the appended claims and from the appended claims.

10: tread mill 11: wire
100: under-rehabilitation device 110: motor
120: frame 130: pulley
140: Information receiving unit 150:
160: display unit 170: end effector
380: slider 390: linear actuator

Claims (14)

Tread mill;
An end effector secured to the body part of the patient;
A plurality of motors rotating forward and backward to wind or loosen a plurality of wires connected to the end effector;
Calculating a difference between a gait locus of the patient and a preset gait locus calculated through a tension on the plurality of wires in accordance with the movement of the end effector when the patient is walking on the treadmill, A control unit;
Front and rear frames mounted on the treadmill;
A plurality of pulleys disposed in the front and rear frames to guide the wires;
A slider slidably coupled to the front frame, the slider having the plurality of pulleys rotatably connected thereto; And
And a linear actuator that continuously slides the slider coupled with the plurality of pulleys in accordance with the gait of the patient. The method according to claim 1,
An information receiving unit coupled to each of the motors to sense tension of the wires; And
And a display unit for outputting information about the tension and a result of calculating a difference between the two walking trajectories. 3. The method of claim 2,
Wherein the control unit uses a computed torque method for controlling a non-linear element to suppress a negative tension when generating a control signal for driving the plurality of motors. The method according to claim 1,
Wherein the end effector comprises a plurality of end effectors so that the end effector can be fixed to at least two of the body parts of the patient. delete The method according to claim 1,
Wherein the control unit uses a computed torque method for controlling a non-linear element to suppress a negative tension when generating a control signal for driving the plurality of motors. The method according to claim 6,
The control unit generates an additional control signal for driving the linear driver and generates a control signal for driving the linear driver by using a computed torque to suppress a negative tension by excluding a non- method). (A) moving the end effector mounted by the patient as the patient starts walking on the tread mill;
(B) receiving information about a tension on a wire connected to the end effector according to a walking speed of a patient and detecting an actual walking trajectory of the patient;
(C) calculating an error by comparing a preset gait locus and an actual gait locus of the patient; And
(D) controlling the plurality of motors connected to each wire to rotate forward or reverse so as to adjust the tension of the wire by the difference according to the error by winding or unwinding the wire,
The step (d)
And a control unit for generating a further control signal for controlling a preceding driver that continuously slides the slider coupled with the plurality of pulleys guiding the wire so as to adjust the tension of the wire. 9. The method of claim 8,
Before the step (c)
(E) converting information about the received tension into kinematic information,
Wherein the kinematic information is positional information that can be specified in two-dimensional coordinates, and the walking trajectory of the actual patient is displayed. 10. The method of claim 9,
Wherein the step (e) controls non-linear elements generated while converting the received information into kinetic information. 11. The method of claim 10,
Wherein the step (e) further comprises: (f) outputting the kinematical information converted into the two-dimensional coordinate to the display unit. 9. The method of claim 8,
Wherein the step (c) further comprises the step (g) of comparing the two trajectories and outputting a result of calculating an error to the display unit. 9. The method of claim 8,
The step (d)
And controlling the position coordinate information according to the error between the two walking trajectories to a control signal for controlling the motor, thereby suppressing nonlinear elements and generating a control signal according to the error. 14. The method of claim 13,
The step (d)
And suppresses non-linear elements while generating said additional control signal.

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