KR101940898B1 - Downhill walking control method of wearable exoskeleton robot - Google Patents

Abstract

The present invention relates to a method of controlling a downward walking control of a wearable type exoskeleton robot, and more particularly, to a method of controlling a downward walking control method of a wearable exoskeletal robot by determining a downward walking state on the basis of a vertical positional difference of a front end portion of a foot of the robot, The present invention relates to a method of controlling a walking type exoskeleton robot.

Description

[0001] DOWNHILL WALKING CONTROL METHOD OF WEARABLE EXOKELETON ROBOT [0002]

The present invention relates to a method of controlling a downward walking control of a wearable type exoskeleton robot, and more particularly, to a method of controlling a downward walking control method of a wearable exoskeletal robot by determining a downward walking state on the basis of a vertical positional difference of a front end portion of a foot of the robot, The present invention relates to a method of controlling a walking type exoskeleton robot.

A wearable exoskeleton robot is a robot system to be worn by a person to assist the wearer with the force or motion. Exoskeleton robots for supporting or strengthening lower extremity muscles have been developed mainly for rehabilitation of elderly persons / persons with disabilities, for supporting muscular strength in daily life, and for improving work efficiency by supporting worker's strength in industrial fields. Recently, The development of a muscle-strengthening exoskeleton robot for military purposes is required.

 It is a common practice to repeatedly judge the stance mode of the exoskeleton robot to support the load of the robot as the foot touches the ground and the swing mode in which the foot is dropped from the ground, and to control the robot so as to assist the wearer. However, military muscle strengthening exoskeleton robots need to be operated on various road surfaces such as slopes, stairs, and trenches. To control the exoskeleton robots, control method conversion and parameter optimization through road surface condition estimation are additionally needed. In the case of a relatively rising slope, it is easy to judge that the step or the ramp is on the rise when the front leg contacts the ground. However, in the case of the downward slope, if the posterior stance mode leg is recognized as being flat and the hip joints 160 and 260 and the knee joints 140 and 240 are not bent It is difficult to judge that it is a descending slope or a descending stairway in the swing state of the preceding leg. In particular, in a state in which a load or the like is carried, there is a problem that it becomes more difficult to secure the walking stability.

Korean Patent No. 10-1049526 (Jul. 2011)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to provide a wearable exoskeleton robot for judging a downward walking state based on a vertical positional difference of a front end portion of a pair of wearable exoskeleton robots, The present invention provides a method for controlling a downward walk.

The downward walking control method of the wearing-type exoskeletal robot according to the embodiment of the present invention

A method of controlling a wearable exoskeletal robot, comprising: determining a walking state of a wearer; Calculating a vertical position difference of the front end of the plantar links (110, 120); Determining whether the user is walking downhill based on the calculation result; And controlling the posture of the robot when the wearer is walking downhill.

In addition, the step of determining the walking state may be performed through a sensor mounted on the plantar links 110 and 120.

The vertical position difference of the front ends of the plantar links 110 and 120 may be calculated by comparing A values of the plantar links 110 and 120 according to Equation (1).

[Equation 1]

_{Pelvis X} = L sin A (θ _roll) + L _{thigh X} cos (θ _hip - θ _{_pitch trunk)} + L _{shank X} cos (θ + θ _{hip knee} - θ _{trunk_pitch)} + L _{foot X} sin (-θ _hip - θ _knee - _ankle θ + θ _{trunk _pitch)}

(L _{pelvis ,} L _{thigh ,} L _{shank , and} L _foot mean the length of the pelvis links 170 and 270 in the lateral direction, the lengths of the thigh links 150 and 250, the lengths of the calf links 130 and 230, and the lengths of the foot links 110 and 120, respectively. _roll, θ _hip, θ _knee, θ _ankle, θ _{trunk _pitch} each robot body based on the pitch angle, the thigh link (150 250) of the hip joint (180 280), the roll angle, the vertical reference hip joint (160 260) of the hip joint (180 280) of the reference Knee joint (140,240) Pitch angle, calf link (130,230) Vertical reference Ankle (120,220) Pitch angle, pitch angle of robot upper body)

In addition, the vertical position difference of the front ends of the plantar links 110 and 120 may be calculated in the case where the foot located relatively forward as a result of the determination of the walking condition is in the swing phase.

In addition, the step of determining whether or not the walking is a downward movement may be performed by comparing the difference of the A values of the plantar links 110 and 120 with a preset threshold value.

Further, the posture control step may be characterized by controlling the leg in a stance state.

Further, it is possible to control at least one joint selected from among the hip joints 160 and 260, the knee joints 140 and 240, and the ankle joints 120 and 220 in the stance state.

According to the present invention, it is determined that the wearer is in the downward walking state based on the difference in the vertical position of the front end of the foot of the wearable exoskeleton robot. Thus, it is determined that the wearer is in the downward walking state, .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a link length and a joint angle of a robot in a downward walking control method of a wearable exoskeletal robot according to an embodiment of the present invention; FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a walking-type exoskeletal robot, and more particularly,
FIG. 3 is a graph showing a step-down walking test result of the exoskeleton robot in the downward walking control method of the wearable exoskeletal robot according to the embodiment of the present invention.
FIG. 4 is a flowchart schematically illustrating a method of controlling a downward walking control of a wearable exoskeletal robot according to an embodiment of the present invention. FIG.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best way And should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A method of controlling a downward walking control of an exoskeletal robot according to an exemplary embodiment of the present invention includes: determining a walking state of a foot of a wearer (S100); Calculating a vertical position difference of the front end of the foot links 110 and 120 of the robot (S200); (S300) of determining whether the user is walking downhill based on the calculation result; And controlling the posture of the robot when the wearer is walking downhill (S400).

At this time, when the foot is in the swing state and the other foot is in the stance state, it is determined that the vertical position of the end portion of the front end of the foot links 110 and 120 of the robot worn on each foot, Direction position.

The determination of the walking state (S100) may be performed through the foot of the robot, that is, the pressure sensor mounted on the soles of the feet 110 and 120, and the like. Generally, the sole links 110 and 120 are divided into a stance state in contact with the ground and a swing state in which the sole links 110 and 120 are not in contact with the ground. However, a detailed description thereof will be omitted here.

FIG. 1 is a view schematically showing a link length and a joint angle of a robot in a downward walking control method of a wearable exoskeletal robot according to an embodiment of the present invention,

FIG. 2 is a schematic view illustrating a method for determining whether a wearer is walking downward in a walking-down control method for a wearable exoskeletal robot according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a difference (S200) in the vertical direction of the front end of the plantar links 110 and 120 can be obtained by the following equation (1). Here, the A value of Equation 1 is a value obtained by calculating the vertical distance to the end of the plantar links 110 and 120 with reference to the D _toe value shown in FIG. 2, that is, the roll rotation center of the pelvic joints 180 and 280.

Specifically, the positional difference of the feet in the vertical direction can be calculated by comparing A values of each foot according to Equation (1). Equation (1) is as follows.

[Equation 1]

_{Pelvis X} = L sin A (θ _roll) + L _{thigh X} cos (θ _hip - θ _{_pitch trunk)} + L _{shank X} cos (θ + θ _{hip knee} - θ _{trunk_pitch)} + L _{foot X} sin (-θ _hip - θ _knee - _ankle θ + θ _{trunk _pitch)}

In this case, L _{pelvis ,} L _{thigh ,} L _{shank , and} L _foot are the lengths of the pelvis links 170 and 270 in the left and right direction, the lengths of the thigh links 150 and 250, and the lengths of the calf links 130 and 230, respectively vertical reference hip joint of the foot links 110 and 120 indicates the length, and θ _roll, θ _hip, θ _knee, θ _ankle, θ _{trunk _pitch} each robot body based on pelvic joint (180 280), the roll angle, pelvic joint (180 280) of the ( A pitch angle of the thigh links 150 and 250 and a pitch angle of the upper knee joint 140 and 240. The vertical reference ankle 120 and 220 pitch angle and the pitch angle of the upper body of the robot.

In addition, the roll direction and the pitch direction angle of each joint are (+) direction in the arrow direction in Fig.

Link length Joint angle L _pelvis The lateral length of the pelvis link θ _roll Roll angle of pelvic joint based on robot body L _thigh Thigh Link Length θ _hip Pitch angle of vertical hip of hip joint L _shank Calf link length θ _knee Thigh Link Criteria Knee Pitch Angle L _foot Foot link length θ _ankle Calf Link Vertical Reference Ankle Pitch Angle θ _{trunk _pitch} Pitch direction angle of robot body
(Forward direction +)

In this way, a value A obtained by calculating the distance Dtoe shown in FIG. 2 for each foot, that is, the distance in the vertical direction from the center of rotation of the pelvis roll to the toe can be obtained. If the difference value is greater than the predetermined threshold value, the wearer can determine whether the wearer is going down the stairs 300 or the slope (S300).

However, the step (S200) of calculating the above-mentioned A value is performed when the foot is a swing state is located at the front in the walking state determined that the relative, and specifically, comparing θ _hip of the right and left leg θ _hip is relatively more It is only when the big front leg is swinging. This is to prevent the condition from being applied in the step-up (step) 300 / inclined road surface.

In the posture control step S400, it is preferable to control the leg in the stance state, which is the leg supporting the load, but the posture of the leg in the swing state can also be controlled to smooth the movement of the load.

The posture control step S400 may be performed by adjusting a force and an angle acting on any one or more of the joints selected from the stance state of the legs 160 and 260, the knee joints 140 and 240, and the ankle joints 120 and 220 .

Specifically, the vertical distance of the ends of the feet is calculated using the calculated A value, and a swing or stance state of both legs is determined by using a sensor capable of confirming the foot contact, When the vertical distance of the state foot exceeds a predetermined value, the exoskeleton robot judges that the wearer is going downhill and adjusts the force and / or angle of the hip joint and the knee joint of the stance leg of the robot supporting the robot and the additional load, The control of lowering the posture is done.

FIG. 3 is a graph showing a step-down walking test result of the step 300 of the exoskeletal robot in the downward walking control method of the wearable exoskeletal robot according to the embodiment of the present invention.

This is a result of a test in which the mode (swing / stance) of both legs of the exoskeletal robot and the vertical distance from the pivotal link 170 to the toe of the pivot link 170 are measured by a step-down walking test 300, It is possible to determine whether or not the wearer is walking down by calculating the change of the position value of the feet of the feet in the vertical direction, thereby controlling the joint of the leg in the stance state, It is possible to secure the walking stability of the vehicle.

Specifically, in FIG. 3, as a result of a test for lowering the right foot, when the left foot stance is lowered in the downward direction of the right foot from the right foot swing state, So that the posture of the right leg can be lowered so as to land on the lower part of the stairs.

Although the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, The present invention is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and variations are possible within the scope of the present invention, and it is obvious that those parts easily changeable by those skilled in the art are included in the scope of the present invention .

100: left leg
110, 210: sols link
120,220: Ankle joint
130,230: Calf Link
140,240: knee joint
150,250: Thigh Link
160,260:
170,270: Pelvic Link
180,280: Pelvic Joint
200: Right leg
300: Stairs
400:

Claims (7)

A method of controlling a wearable exoskeletal robot,
Determining a wearer's walking state;
Calculating a vertical position difference of the front leg link of the legs of the robot;
Determining whether the user is walking downhill based on the calculation result;
Controlling the posture of the robot when the wearer is walking downhill;
Including,
Wherein the calculating the vertical position difference comprises:
And calculating a difference in vertical distance from the center of rotation of the pelvic joint of the wearing type exoskeletal robot to the front end of the soles of the foot of the wearer,
The step of determining whether the person is walking downhill comprises:
And comparing the vertical position difference with a preset threshold value to determine whether to walk down when the foot is greater than the threshold regardless of whether the foot is in contact with the ground,
Wherein the step of controlling the posture of the robot is performed immediately after deciding that the robot is going to descend by the step of determining whether the robot is going to be walked downhill. The method according to claim 1,
Wherein the step of determining the walking state is performed through a sensor mounted on the plantar link.
The method according to claim 1,
Wherein the vertical position difference of the front foot of the foot link is calculated by comparing A values of each foot according to Equation (1).

[Equation 1]
_{Pelvis X} = L sin A (θ _roll) + L _{thigh X} cos (θ _hip - θ _{_pitch trunk)} + L _{shank X} cos (θ + θ _{hip knee} - θ _{trunk_pitch)} + L _{foot X} sin (-θ _hip - θ _knee - _ankle θ + θ _{trunk _pitch)}

(Where L _{pelvis ,} L _{thigh ,} L _{shank , and} L _foot mean the length of the pelvis link in the left and right direction, thigh link length, calf link length, and foot link length, respectively, and θ _{roll ,} θ _{hip ,} θ _{knee ,} θ _{ankle , trunk _pitch} refers to the roll angle of the pelvic joint according to the robot body, the pitch angle of the vertical hip joint of the pelvis joint, the pitch angle of the knee joint of the thigh link, the pitch angle of the ankle joint of the vertical reference ankle, and the pitch direction of the robot upper body)
The method of claim 3,
Wherein the vertical position difference of the front foot of the soles of the foot is calculated at a time when the feet located relatively forward as a result of the walking state determination are in a swing state.
delete The method according to claim 1,
Wherein the posture controlling step controls a leg in a stance state.
The method according to claim 6,
And controlling at least one joint selected from among the hip, knee, and ankle joints of the leg in the stance state.

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