# US 10,765,583 B2 · Wearable walking assist robot and method for controlling the same

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- Number: US 10,765,583 B2
- Document ID: US10765583B2
- Status: Granted
- Kind: B2
- Application number: 15/280,155
- Filed: 2016-09-29
- Published: 2017-11-23
- Granted: 2020-09-08
- Earliest claimed: 2016-05-19
- Assignees: Hyundai Motor Company
- Applicants: Hyundai Motor Company
- Inventors: Dong Jin Hyun; Kyung Mo Jung; Sang In Park; Hyun Seop Lim
- Web page: https://patentgrep.com/patent/US10765583B2

## CPC

- A61H 3/00: Appliances for aiding patients or disabled persons to walk about (apparatus for helping babies to walk A47D13/04 {; applying electrical currents by contact electrodes for stimulating motor muscles, e.g. walking assistance A61N1/36003})
- A61F 2/72: Bioelectric control, e.g. myoelectric
- A61H 1/024: {Knee (A61H1/0255 takes precedence)}
- A61H 1/0244: {Hip (A61H1/0255 takes precedence)}
- A61H 2201/164: Feet or leg, e.g. pedal
- A61H 2201/165: Wearable interfaces
- A61H 2201/5015: using specific interfaces or standards, e.g. USB, serial, parallel
- A61H 2201/5061: Force sensors
- A61H 2201/5074: using electric pressure transducers with proportional output
- A61H: PHYSICAL THERAPY APPARATUS, e.g. DEVICES FOR LOCATING OR STIMULATING REFLEX POINTS IN THE BODY; ARTIFICIAL RESPIRATION; MASSAGE; BATHING DEVICES FOR SPECIAL THERAPEUTIC OR HYGIENIC PURPOSES OR SPECIFIC PARTS OF THE BODY (electrotherapy, magnetotherapy, radiation therapy or ultrasound therapy A61N)
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)

## Abstract

A wearable walking assist robot is provided that ensures high walking assistance performance without a complex calculation process by detecting a gait phase based on pressure distribution on feet and performing a corresponding control mode that is set in advance. The wearable walking assist robot includes a sensor unit that senses pressure on the soles of the feet of a wearer and a controller that determines gait phases of both a first leg to be operated and a second leg based on the sensed pressure. Additionally, the controller selects one of a plurality of control modes set in advance based on the determined gait phases and operates a joint-driving unit for the first leg to be operated.

## Claims

### Claim 1

A wearable walking assist robot, comprising:
a sensor unit configured to sense pressure on the soles of the feet of a user; and
a controller configured to determine gait phases of both a first leg to be operated and a second leg based on the pressure sensed by the pressure sensor unit, select one of a plurality of control modes set in advance based on the determined gait phases, and operate a joint-driving unit for the first leg to be operated,
wherein the controller is configured to determine one selected from the group including a ground impact absorbing mode as a control mode for the first leg to be operated based on the gait phases of both the first leg to be operated and the second leg, and
wherein the ground impact absorbing mode is a mode in which the controller is configured to generate a virtual spring-damper in a longitudinal direction of a line connecting hip joint and an end of the first leg to each other of the walking assist robot and operate the joint-driving unit, using impedance control to make the first leg of the robot absorb shock from the outside.

### Claim 2 (depends on 1)

The robot of claim 1, wherein the pressure sensor unit includes a plurality of pressure sensors configured to sense pressure applied to the toes and the heels of the soles.

### Claim 3 (depends on 2)

The robot of claim 2, wherein the controller is configured to determine that the toes and the heels are in contact with the ground when pressure applied to the toes and the heels is greater than a predetermined threshold, and determine that the toes and the heels are not in contact with the ground when the pressure is less than the threshold.

### Claim 4 (depends on 3)

The robot of claim 3, wherein the controller is configured to determine the gait phases by combining a ground-contact state and a non-ground-contact state of the toe and the heel of the first leg to be operated with a ground-contact state and a non-ground-contact state of the toe and the heel of the second leg.

### Claim 5 (depends on 4)

The robot of claim 4, wherein the controller is configured to:
determine as a gait phase that a corresponding leg is supported on the ground throughout the sole when the toe is in contact with the ground and the heel is in contact with the ground,
determine as a gait phase that a corresponding leg is supported on the toe on the ground when the toe is in contact with the ground and the heel is not in contact with the ground,
determine as a gait phase that a corresponding leg is supported on the heel on the ground when the toe is not in contact with the ground and the heel is in contact with the ground, and
determine as a gait phase that a corresponding leg is in the air when both the toe and the heel are not in contact with the ground.

### Claim 6 (depends on 1)

The robot of claim 1, wherein the controller is configured to determine one selected from the group consisting of: a weight bearing mode, a compensation of mechanical impedance mode, a ground impact absorbing mode, the ground impact absorbing and extension of virtual leg mode, a pushing ground mode, and a ready for swing phase mode, as the control mode for the first leg to be operated based on the gait phases of both the first leg to be operated and the second leg.

### Claim 7 (depends on 6)

The robot of claim 6, wherein the weight bearing mode is a mode in which the controller is configured to operate the joint-driving unit to push the user in a gravity direction with a predetermined force.

### Claim 8 (depends on 6)

The robot of claim 6, wherein the compensation of mechanical impedance mode is a mode in which the controller is configured to operate the joint-driving units to compensate for friction at the joints and weight of the robot due to the gravity.

### Claim 9 (depends on 6)

The robot of claim 6, wherein the ground impact absorbing and extension of virtual leg mode is a mode in which the controller is configured to set a balance point in a impedance control direction for the virtual legs as 0 degrees and operate the joint-driving unit to pull the virtual leg to be vertically erected while making a virtual spring-damper in a longitudinal direction of a line connecting a hip joint and the end of the first leg to each other of the walking assist robot and operating the joint-driving unit, using impedance control to make the first leg of the robot absorb shock from the outside.

### Claim 10 (depends on 6)

The robot of claim 6, wherein the pushing ground mode is a mode in which the controller is configured to operate the joint-driving unit to push the end of the first leg to be controlled in −x and −y directions in a rectangular coordinate system.

### Claim 11 (depends on 6)

The robot of claim 6, wherein the ready for swing phase mode is a mode in which the controller is configured to operate the joint-driving unit to push the end of the first leg to be controlled in +x and +y directions in a rectangular coordinate system for swing of the first leg.

### Claim 12 (depends on 6)

The robot of claim 6, wherein when the control mode changes, the controller is configured to apply a transition parameter, which changes from 0 to 1 along a sinusoidal path for a predetermined time interval, to adjust torque applied to the joint-driving units in a previous mode and to adjust torque to be applied to the joint-driving unit in a new changed control mode.

### Claim 13

A method for controlling a wearable walking assist robot, comprising:
sensing, by a pressure sensing unit, pressure on the soles of the feet of a user; and
determining, by a controller, gait phases of both a first leg to be operated and a second leg based on the pressure sensed by the pressure sensor unit; and
selecting, by the controller, one of a plurality of control modes set in advance based on the determined gait phases and operating a joint-driving unit of the first leg to be operated,
wherein the operating of a joint-driving unit includes determining one selected from the group including a ground impact absorbing mode as a control mode for the first leg to be operated based on the gait phases of both the first leg to be operated and the second leg, and
wherein the mode of the first leg to be operated is determined as the ground impact absorbing mode, a virtual spring-damper is generated in a longitudinal direction of a line connecting a hip joint and an end of the first leg to each other of the walking assist robot and the joint-driving unit is operated using impedance control to make the first leg of the robot absorb shock from the outside.

### Claim 14 (depends on 13)

The method of claim 13, wherein the sensing of pressure includes sensing pressure applied to the toes and the heels of the soles.

### Claim 15 (depends on 14)

The method of claim 14, wherein the determining of gait phases includes determining that the toes and the heels are in contact with the ground when pressure applied to the toes and the heels is greater than a predetermined threshold, and determining that the toes and the heels are not in contact with the ground when the pressure is less than the threshold.

### Claim 16 (depends on 15)

The method of claim 15, wherein determining of gait phases includes determining the gait phases by combining a ground-contact state and a non-ground-contact state of the toe and the heel of the first leg to be operated with a ground-contact state and a non-ground-contact state of the toe and the heel of the second leg.

### Claim 17 (depends on 16)

The method of claim 16, wherein the determining of gait phases includes:
determining, by the controller, as a gait phase that a corresponding leg is supported on the ground throughout the sole when the toe is in contact with the ground and the heel is in contact with the ground,
determining, by the controller, as a gait phase that a corresponding leg is supported on the toe on the ground when the toe is in contact with the ground and the heel is not in contact with the ground,
determining, by the controller, as a gait phase that a corresponding leg is supported on the heel on the ground when the toe is not in contact with the ground and the heel is in contact with the ground, and
determining, by the controller, as a gait phase that a corresponding leg is in the air when both the toe and the heel are not in contact with the ground.

### Claim 18 (depends on 13)

The robot of claim 13, wherein the operating of a joint-driving unit includes determining one selected from the group consisting of: a weight bearing mode, a compensation of mechanical impedance mode, the ground impact absorbing mode, a ground impact absorbing and extension of virtual leg mode, a pushing ground mode, and a ready for swing phase mode, as the control mode for the first leg to be operated based on the gait phases of both the first leg to be operated and the second leg.

### Claim 19 (depends on 18)

The method of claim 18, wherein in the operating of a joint-driving unit, when the mode of the first leg to be operated is determined as the weight bearing mode, the joint-driving unit is operated to push the user in a gravity direction with a predetermined force.

### Claim 20 (depends on 18)

The method of claim 18, wherein in the operating of a joint-driving unit, when the mode of the first leg to be operated is determined as the compensation of mechanical impedance mode, the joint-driving unit is operated to compensate for friction at the joint and weight of the robot due to the gravity.

### Claim 21 (depends on 18)

The method of claim 18, wherein in the operating of a joint-driving unit, the mode of the first leg to be operated is determined as the ground impact absorbing and extension of virtual leg mode, a balance point is set in a impedance control direction for a virtual leg as 0 degree and the joint-driving unit is operated to pull the virtual leg to be vertically erected while a virtual spring-damper is generated in a longitudinal direction of a line connecting a hip joint and the end of a leg to each other of the walking assist robot and the joint-driving unit is operated using impedance control to make the leg of the robot absorb shock from the outside.

### Claim 22 (depends on 18)

The method of claim 18, wherein in the operating of a joint-driving unit, the mode of the first leg to be operated is determined as the pushing ground mode, the joint-driving unit is operated to push the end of the first leg to be operated in −x and −y directions in a rectangular coordinate system.

### Claim 23 (depends on 18)

The method of claim 18, wherein in the operating of a joint-driving unit, the mode of the first leg to be operated is determined as the ready for swing phase mode, the joint-driving unit is operated to push the end of the leg in +x and +y direction in a rectangular coordinate system for swing of the first leg to be operated.

### Claim 24 (depends on 18)

The method of claim 18, wherein the operating of a joint-driving unit includes:
determining, by the controller, whether the control mode changes; and
when the control mode changes, applying, by the controller, a transition parameter, which changes from 0 to 1 along a sinusoidal path for a predetermined time interval to adjust torque applied to the joint-driving units in a previous mode and to adjust torque to be applied to the joint-driving units in a new changed control mode.