US-20260124093-A1 - GAIT REHABILITATION ROBOT AND TRAINING METHOD THEREOF

US20260124093A1US 20260124093 A1US20260124093 A1US 20260124093A1US-20260124093-A1

Abstract

Described are a gait rehabilitation robot and gait rehabilitation robot and training method thereof, the gait rehabilitation robot including: a pair of footplates; a pair of footplate supports; a pair of gait actuators; a controller; and a memory, wherein the controller receives at least one of a state value and a control command value relating to the corresponding motor from each gait actuator under a load condition, and calculates anteroposterior forces exerted on each of the footplates by the corresponding foot during the gait training based, for each gait actuator, on a difference between at least one of the received state value and control command value and the corresponding reference value stored in the memory for a present gait trajectory and speed. Thus, a gait status can be determined based on the difference between the anteroposterior forces exerted on each footplate under no-load and load conditions.

Inventors

Sun Hee HWANG
Jun Sik Moon
Jae Woong Youn
Young Hwan Kim
Man Soo KO
David A. Brown

Assignees

CUREXO, INC.
THE BOARD OF REGENTS OF THE UNIVERSITY OF TEXAS SYSTEM

Dates

Publication Date: 20260507
Application Date: 20251105
Priority Date: 20241107

Claims (20)

1 . A gait rehabilitation robot comprising: a pair of footplates configured to place left and right feet of a trainee thereon for gait training; a pair of footplate supports, each connected to a corresponding footplate; a pair of gait actuators configured to actuate respective footplates and respective footplate supports, each gait actuator comprising a motor for moving the corresponding footplate in anterior and posterior directions, and a motor driver for controlling the motor; a controller configured to control the pair of gait actuators to move and rotate the respective footplates based on a preset gait trajectory and speed; and a memory configured to store reference values for at least one of state and control of each of the motors according to the preset gait trajectory and speed, wherein the controller receives at least one of a state value and a control command value relating to the corresponding motor from each gait actuator under a load condition, and calculates anteroposterior forces exerted on each of the footplates by the corresponding foot during the gait training based, for each gait actuator, on a difference between at least one of the received state value and control command value and the corresponding reference value stored in the memory for a present gait trajectory and speed.
2 . The gait rehabilitation robot of claim 1 , wherein the reference values comprise at least one of a current value, a torque value, a position value, a speed value, a current command value, a force command value, a position command value, and a speed command value of the motor under a no-load condition, the state value comprises at least one of a current value, a torque value, a position value, and a speed value of the motor, and the command value comprises at least one of a current command value, a position command value, a speed command value, and a torque command value.
3 . The gait rehabilitation robot of claim 1 , wherein each gait actuator further comprises a current sensor configured to sense a current of the motor, the reference values of the motor comprise a first current value of the motor measured by the current sensor under the no-load condition or a first torque value calculated based on the first current value, the state value comprises a second current value of the motor measured by the current sensor under the load condition or a second torque value calculated based on the second current value, and the controller calculates the anteroposterior forces exerted on each of the footplates by the corresponding foot, based on a difference between the second current value or second torque value of the corresponding motor under the load condition and the first current value or first torque value of the corresponding motor under the no-load condition.
4 . The gait rehabilitation robot of claim 1 , wherein the reference values of the motor comprise a first current command value or first torque command value applied by the motor driver under the no-load condition, the command value comprises a second current command value or second torque command value applied by the motor driver under the load condition, and the controller calculates the anteroposterior forces exerted on each of the footplates by the corresponding foot, based on a difference between the second current command value or second torque command value of the corresponding motor under the load condition and the first current command value or first torque command value of the corresponding motor under the no-load condition.
5 . The gait rehabilitation robot of claim 1 , wherein each gait actuator further comprises an encoder connected to the motor and configured to detect a position and speed of the motor, the reference values of the motor comprise a first position value or first speed value of the motor under the no-load condition, the state value comprises a second position value or second speed value of the motor, calculated by the encoder under the load condition, and the controller calculates the anteroposterior forces exerted on the footplate by the feet, based on a difference between the first position value or first speed value and the first position value or second position value.
6 . The gait rehabilitation robot of claim 1 , wherein the controller generates and provides training feedback information related to a gait training status of the trainee based on comparison between the anteroposterior forces of a reference-side footplate in a first step and a training-side footplate in a second step, and the training feedback information comprises at least one of visual feedback information, auditory feedback information, and tactile feedback information.
7 . The gait rehabilitation robot of claim 1 , wherein the reference values comprises state values or control values of the motor acquired according to a plurality of different gait trajectories and a plurality of different speeds by controlling each gait actuator to operate along the plurality of different gait trajectories and at the plurality of different speeds under the no-load condition, or comprises a control value of state value of the motor determined by a robot model.
8 . The gait rehabilitation robot of claim 1 , wherein the controller synchronizes at least one of the state value and command value of each motor with the reference values according to gait cycles, and calculates differences between the at least one of the synchronized state value and command value and the reference values throughout the gait cycle.
9 . The gait rehabilitation robot of claim 1 , further comprising a user interface (UI) generator configured to generate a first UI menu for setting a target range of anteroposterior forces exerted on a training-side footplate by the trainee compared to the anteroposterior forces exerted on a reference-side footplate, wherein the controller compares absolute values of anteroposterior forces exerted on the reference-side footplate in a first step with absolute values of anteroposterior forces exerted on the training-side footplate in a second step, and determines that the gait training of the trainee is in a normal state upon the anteroposterior forces exerted on the training-side footplate falling within the target range, but determines that the gait training is in an abnormal state upon the anteroposterior forces exerted on the training-side footplate falling outside the target range.
10 . The gait rehabilitation robot of claim 1 , further comprising: a user interface (UI) generator configured to generate a first UI menu for setting a target range of anteroposterior forces exerted on a training-side footplate by the trainee compared to the anteroposterior forces exerted on a reference-side footplate; and a display, wherein the controller controls the UI generator to generate a second UI menu that represents the magnitudes of anteroposterior forces exerted on the reference-side footplate and the training-side footplate with respect to a target range and to display the second UI menu on the display.
11 . The gait rehabilitation robot of claim 1 , further comprising: a user interface (UI) generator configured to generate a first UI menu for setting a target value of anteroposterior forces exerted on the training-side footplate by the trainee compared to the anteroposterior forces exerted on the reference-side footplate; wherein the training feedback information includes virtual reality-based feedback information corresponding to each wherein the controller is further configured to calculate a difference between the anteroposterior forces exerted on the training-side footplate and the target value, and to generate and provide virtual reality-based feedback information corresponding to one of the plurality of the training states based on the calculated difference.
12 . The gait rehabilitation robot of claim 10 , further comprising a loudspeaker, wherein the controller generates an audio feedback signal that indicates timing of the anteroposterior forces to be exerted on the training-side footplate and controls the loudspeaker to output the audio feedback signal, upon the anteroposterior forces exerted on the training-side footplate falling outside the target range or upon timing of the anteroposterior forces exerted on the training-side footplate being incorrect.
13 . The gait rehabilitation robot of claim 1 , further comprising: a user interface (UI) generator configured to generate a UI menu for setting a target value of anteroposterior forces exerted on the training-side footplate by the trainee; wherein the controller corrects at least one of a gait trajectory and speed for at least one of the reference-side footplate and the training-side footplate based on a difference in the anteroposterior forces between the reference-side footplate and the training-side footplate or a difference between the anteroposterior forces of the training-side footplate and the target value.
14 . A gait rehabilitation robot comprising: a pair of footplates configured to place left and right feet of a trainee thereon for gait training; a pair of footplate supports, each connected to a corresponding footplate; a pair of gait actuators configured to actuate respective footplates and respective footplate supports, each gait actuator comprising a motor for moving the corresponding footplate in anterior and posterior directions, an encoder connected to the motor and detecting position and speed of the motor, and a motor driver for controlling the motor; a controller configured to control the pair of gait actuators to move and rotate the respective footplates based on a preset gait trajectory and speed; and a memory configured to store reference values for position or speed of the motor according to the preset gait trajectory and speed, wherein the motor driver calculates a feedback command value based on an error by comparing a position value or speed value of a corresponding motor calculated by the encoder under the load condition with the reference values, and applies the feedback control value to the corresponding motor, and the controller calculates anteroposterior forces exerted on each of the footplates by the corresponding foot during the gait training based on the feedback command value.
15 . A training method of a gait rehabilitation robot comprising a pair of footplates configured to place left and right feet of a trainee thereon for gait training, and a pair of motors for moving each of the pair of footplates in anterior and posterior directions, the training method comprising: storing, for each motor, reference values for at least one of a control or a state of the motor based on a preset gait trajectory and speed; acquiring at least one of a state value and control command value of each motor under a load condition; and calculating anteroposterior forces exerted on each footplate by the corresponding foot during the gait training, based, for each motor, on a difference between at least one of the state value and command value and the corresponding reference values corresponding to a present gait trajectory and speed.
16 . The training method of claim 15 , further comprising generating and providing training feedback information related to a gait training status of the trainee based on comparison between the anteroposterior forces of a reference-side footplate and a training-side footplate, wherein the training feedback information comprises at least one of visual feedback information, auditory feedback information, and tactile feedback information.
17 . The training method of claim 15 , further comprising: setting a target value for the anteroposterior forces exerted on the training-side footplate; and wherein the training feedback information includes virtual reality-based feedback information corresponding to each of a plurality of preset training states; and Wherein the generating and providing the training feedback information comprises calculating a difference between the anteroposterior forces exerted on the training-side footplate and the target value, and generating and providing virtual reality-based feedback information corresponding to one of the plurality of the training states based on the calculated difference.
18 . The training method of claim 15 , wherein the calculating the anteroposterior forces comprises synchronizing at least one of the state value and command value of the motor with the reference values according to gait cycles.
19 . The training method of claim 15 , further comprising: generating and providing a first UI menu for setting a target range of anteroposterior forces exerted on a training-side footplate by the trainee compared to the anteroposterior forces exerted on a reference-side footplate; and generating and providing a second UI menu that represents the magnitudes of anteroposterior forces exerted on the reference-side footplate and the training-side footplate with respect to a target range.
20 . The training method of claim 15 , further comprising: setting a target value for the anteroposterior forces exerted on a training-side footplate; and correcting at least one of a gait trajectory and speed for at least one of a reference-side footplate and the training-side footplate based on a difference in the anteroposterior forces between the reference-side footplate and the training-side footplate, or a difference between the anteroposterior forces of the training-side footplate and the target value.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2024-0157167 filed on Nov. 7, 2024 in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. BACKGROUND Field The disclosure relates to a gait rehabilitation robot and a training method thereof and, more particularly, to a method of providing feedback to a trainee (e.g. patient) based on a horizontal force exerted on a footplate by the trainee, thereby enabling the trainee to actively participate in training. Description of the Related Art In general, a gait rehabilitation robot refers to a robot used for gait rehabilitation therapy or the like, and is utilized in upright sensory enhancement training for patients with lower-limb paralysis caused by spinal cord injury, stroke, traumatic brain injury, muscular dystrophy, Parkinson's disease, multiple sclerosis, cerebral palsy, etc. Various types of gait rehabilitation robots, such as treadmill-type, end-effector-type, and exoskeleton-type robots, are being used. In a fully automated system like the treadmill-type or end-effector-type robot, it is necessary to monitor the gait status of a trainee. Conventionally, there have been cases where the gait rehabilitation robot employs a method of installing a load cell or similar force sensor on a footplate to detect vertical ground reaction forces and provide feedback to a patient. However, a patient's gait ability, such as step length and gait speed, is closely associated with horizontal ground reaction forces. Therefore, providing feedback on the vertical ground reaction forces caused by the shift in the center of mass makes it difficult to achieve effective gait training. SUMMARY To solve the problems described above, an aspect of the disclosure is to estimate anteroposterior forces exerted on a footplate of a gait rehabilitation robot by a trainee and provide feedback, thereby enhancing the effectiveness of gait training. Further, when the estimation of the anteroposterior forces is completed, a threshold value for the force to be generated can be set based on a user's motor function level and transmitted back as a real-time image. According to an embodiment of the disclosure, a gait rehabilitation robot includes: a pair of footplates configured to place left and right feet of a trainee thereon for gait training; a pair of footplate supports, each connected to a corresponding footplate; a pair of gait actuators configured to actuate respective footplates and respective footplate supports, each gait actuator comprising a motor for moving the corresponding footplate in anterior and posterior directions, and a motor driver for controlling the motor; a controller configured to control the pair of gait actuators to move and rotate the respective footplates based on a preset gait trajectory and speed; and a memory configured to store reference values for at least one of state and control of each of the motors according to the preset gait trajectory and speed, wherein the controller receives at least one of a state value and a control command value relating to the corresponding motor from each gait actuator under a load condition, and calculates anteroposterior forces exerted on each of the footplates by the corresponding foot during the gait training based, for each gait actuator, on a difference between at least one of the received state value and control command value and the corresponding reference value stored in the memory for a present gait trajectory and speed. In addition, the reference values may include at least one of a current value, a torque value, a position value, a speed value, a current command value, a force command value, a position command value, and a speed command value of the motor under a no-load condition, the state value may comprise at least one of a current value, a torque value, a position value, and a speed value of the motor, and the command value comprises at least one of a current command value, a position command value, a speed command value, and a torque command value. Further, the gait actuator may further include a current sensor configured to sense a current of the motor; the reference values of the motor may include a first current value of the motor measured by the current sensor under the no-load condition or a first torque value calculated based on the first current value; the state value may include a second current value of the motor measured by the current sensor under the load condition or a second torque value calculated based on the second current value; and the controller may calculate the anteroposterior forces exerted on each of the footplates by the corresponding foot, based on a difference between the second current value or second torque value of the corresponding motor under the load condition and the first current value or first torque value of the correspon