KR101361362B1 - Walking Assistance Robot for Actively Determining Moving Speed Based on User Gait Cycle - Google Patents

Abstract

The present invention relates to an electric walking aid robot that detects a walking cycle of a user such as an elderly person and actively determines a moving speed. According to an aspect of the present invention, a method of operating a walking assistance robot that assists a user in walking aid mode is based on an output of an infrared sensor and an acceleration sensor using a walking detection sensor module attached to a user's shoe. Detecting a walking period, a standing unit, or a stinging machine, transmitting the detected information by a wireless local area communication method, and a walking period of the user received from the walking detection sensor module by the walking assistance robot, the standing unit, Or a wheel connected to the motor in accordance with the movement speed control using the information on the stator.

Description

Walking Assistance Robot for Actively Determining Moving Speed Based on User Gait Cycle}

The present invention relates to an electric walking aid robot, and more particularly, to an electric walking aid robot that detects a walking cycle of a user such as an elderly person and actively determines a moving speed.

Recently, life expectancy of the elderly is increasing with the improvement of quality of life, and technology for supporting the basic life of the elderly is becoming a hot topic. Older people lose strength rapidly after age 65 due to physical aging, resulting in large and small diseases. Among them, lowering muscle strength is a factor that hinders walking behavior.

The method of supporting walking behavior generally supports the walking of the elderly by using passive walking aids and walking aids. However, these assistive devices are operated by the additional force that the elderly person has to move the assistive device apart from the force required for walking. Therefore, the research of walking aid robot to facilitate such walking assistance is actively progressing and is reaching the commercialization stage. Steering method of the existing walking aid robot is developed with various HMI (Human Machine Interface). However, in most steering methods, the speed of the walking aid robot varies according to the grip strength or pushing force of the elderly hand. This steering method is a safety risk due to the wrong operation of the operator.

Accordingly, an object of the present invention is to solve the above-described problems, and an object of the present invention is to provide an infrared sensor and an acceleration sensor manufactured to distinguish a stance period and a swing period of a user's shoe such as an elderly person. By attaching a fused module, the user's walking period, standing angle, and stirrup, which are measured based on one-foot grounding time, are acquired and transmitted through short-range wireless communication, the control unit safely walks the user based on the received data. It is to provide an electric walking aid robot that actively determines the assisted moving speed.

First, to summarize the features of the present invention, in accordance with an aspect of the present invention, the walk assistance robot for assisting the user walking in the walk aid mode, the first to wirelessly receive information from the walk detection sensor module attached to the user's shoes 1 short range communication module; A control unit which determines a moving direction and a moving speed while assisting a user walking, and controls a moving speed using information received from the walking detection sensor module; And a motor that rotates the wheel according to the movement speed control of the controller, wherein the gait detection sensor module is an infrared sensor for irradiating infrared rays and generating an electrical signal corresponding to the reflected amount of infrared rays, gravity according to the user's walking An acceleration sensor for generating an electrical signal corresponding to an acceleration value in a direction axis and a moving direction axis, and a signal processor detecting a walking period, a standing unit, or a stir of the user based on the outputs of the infrared sensor and the acceleration sensor And a second short range communication module configured to transmit information about the walking period of the user, the stand-up unit, or the stipple unit to the first short range communication module, wherein the control unit receives the first short range communication module. The motor is controlled by using information about a walking period of the user, the stance device, or the stance device.

The signal processor detects the stance based on when the output of the infrared sensor is greater than or equal to a threshold, and the force vector scalar amount, which is the sum of the magnitudes of the forces on the gravity direction axis and the movement direction axis, is greater than or equal to the threshold value according to the output of the acceleration sensor. The gait period of the user is detected based on a time, and the stance period is detected by subtracting the standing angle from the gait period of the user.

The signal processor may vary the threshold value compared with the force vector scalar amount by reflecting a plurality of variations in the previous force vector scalar amount that is greater than or equal to a threshold.

The control unit may be configured to drive the motor such that the walking speed of the user based on the walking period of the user, the stance device, or the stator and the moving speed of the walking assistance robot based on the measured value of the encoder included in the motor are synchronized. The duty ratio of the required PWM signal is determined, and the motor is controlled using the corresponding PWM signal.

In addition, according to another aspect of the present invention, a method of operating a walking assistance robot for assisting a user in walking aid mode is based on the output of an infrared sensor and an acceleration sensor using a walking detection sensor module attached to a user's shoes. Detecting a walking period, a standing period, or a stinging period of the user, and transmitting the detected corresponding information in a wireless local area communication method; And rotating the wheels connected to the motor according to the movement speed control using the walking period of the user received from the walking detection sensor module, the stance device, or the stator at the walking assistance robot.

According to the walking assistance robot according to the present invention, by automatically estimating the moving speed of the user by automatically estimating the walking period of the user, instead of determining the driving speed by using a steering device or a speed manipulation in which a user applies a force to the walking walker. It can assist the user walking safely and conveniently.

1 is a view for explaining a walking assistance robot according to an embodiment of the present invention.
2 is a view for explaining a control module of a walking assistance robot according to an embodiment of the present invention.
3 is a diagram illustrating an eight-step walking process of a general pedestrian.
4 is a photograph of a walking detection sensor module according to an embodiment of the present invention.
5 is a block diagram illustrating a walking detection sensor module according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a force vector of a user's plantar portion for detecting a walking cycle according to an exemplary embodiment of the present invention.
7 is a block diagram illustrating data of a pedestrian detection sensor module according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

First, the walking assistance operation of the walking assistance robot according to an embodiment of the present invention will be briefly described with reference to FIGS. 1 and 2.

According to an embodiment of the present invention, the walking assistance robot may include a control unit as the user manipulates touch sensors or switches (including force sensors for detecting a user's grip force, joystick, handle, etc.) in walking aid mode and wheelchair mode. In 110, the direction and speed of the movement are actively determined, the motor 120 is controlled, and the wheels mounted on the motor 120 are rotated so that the general front, rear, left, and right movements can be made.

When a user who is inconvenient to physical activity as shown in FIG. 1 uses the walking aid robot in walking aid mode, the user may stand and hold the handle and push it forward manually, and may assist the front, rear, left, and right movements according to the manipulation of the touch sensor. Can be. When a user with physical disabilities uses the walking assistance robot in a wheelchair mode, the chair equipped with the walking assistance robot is unfolded so that the user can sit down, and the user sits on the chair and applies a force to a switch or a force sensor with his hand. May be maintained at a constant speed so that walking can be assisted. At this time, the joystick (or handle) of the armrest side may be controlled to move forward, backward, left and right and gradually move in the corresponding direction.

In this movement, the walking assistance robot according to an embodiment of the present invention includes a plurality of acceleration sensors for detecting a speed change, and the controller 110 detects an uphill or downhill using these signals to increase the wheel speed. The motor 120 may be controlled to decrease or increase, and besides, a plurality of ultrasonic sensors for detecting obstacles are provided around the walking aid robot, and the controller 110 detects the obstacles around the wheels by using these signals. The motor 120 may be controlled to reduce or stop the motor. In addition, the walking assistance robot according to an embodiment of the present invention may further include necessary devices such as an acoustic device for guiding an obstacle, an uphill or downhill, or other switch operation.

As described above, the walking assistance robot according to an embodiment of the present invention may operate to assist the user walking safely and comfortably in an uncomfortable physical activity such as the elderly in the walking aid mode and the wheelchair mode, and in addition to the elderly in the walking aid mode. The user's walking cycle is measured based on the ground time of one foot by attaching a module that combines an infrared sensor and an acceleration sensor, which can be distinguished between stance period and swing period. When transmitting through short-range wireless communication such as Bluetooth or Zigbee (see FIG. 5), the controller 110 receiving the short-range communication module 130 may assist the user walking safely based on estimated data such as a walking cycle. By actively determining the moving speed, the motor 120 is controlled at the corresponding speed.

<Method for Detection of Pedestrian Cycle and Synchronization with Gait Assist Robots>

In order to synchronize the moving speed of the walking aid robot and the walking speed of the user according to an embodiment of the present invention, a walking cycle and a walking pattern should be detected. Unlike walking of robot, walking is divided into standing stage and stinging stage, standing stage occupies 60% of the walking cycle and the foot is touching the ground, and standing stage is the period when the foot moves away from the ground. . Therefore, the movement speed of the walking aid robot should be synchronized with the time when the plantar foot moves for actual walking, not the walking speed. Therefore, it is necessary to distinguish the time when the plantar foot is in close contact with the ground during walking and not in close contact. The previously researched walking cycle detection method attaches a force sensing resistor (FSR) to the plantar foot and divides the walking cycle into a stance and an epoch, or uses a tilt sensor, acceleration sensor, gyroscope sensor, vision system, etc. There was an example of detection. This conventional method detects gait by acquiring data from the sensor module and simulating on a separate computer for noise reduction and robust calculation. In this way, pedestrian cycle detection can be effective, but it is not easy to miniaturize and is not suitable for use in pedestrian aided robots. Therefore, in the present invention, as described below, the walking aid robot can easily determine the moving speed appropriately by using the small walking detection sensor module.

<Walk cycle detection method>

Among the research methods for detecting gait cycles, the accelerometer sensor is attached to the ankle part to acquire data and then detects the angle of the leg's moving axis in a separate simulation program, or detects rotational components of x, y, and z values. There is an example of ignoring and converting it into one energy value. In this detection method, the walking cycle can be detected, but since it is difficult to distinguish the ground adhesion time of the plantar part, the present invention was detected as follows. Walking is performed in a total of eight steps as shown in FIG. Among them, the foot contact with the ground is the load reactor, the intermediate stand, and the late stand. Therefore, in the present invention, a small walking detection sensor module as shown in FIG. 4 including an IR sensor and an acceleration sensor is attached to a shoe so as to detect such a walking pattern.

5 is a block diagram illustrating a walking detection sensor module according to an embodiment of the present invention. Referring to Figure 5, the walk detection sensor module according to an embodiment of the present invention that can be used to be attached to the side of the shoe, IR (Infra Red) sensor 210, acceleration sensor 220, signal processor 230, And a wireless local area communication module 240.

The IR sensor 210 is a sensor that irradiates infrared rays using a light source and measures an amount of reflected infrared rays to generate an electrical signal corresponding thereto. Therefore, when the foot is in contact with the ground and irradiated with infrared light from the IR sensor 210 to the ground, the amount of reflection is maximum and the amount of reflection gradually decreases as the foot enters the late standing phase. Accordingly, the signal processor 230 may perform the time when the amount of infrared rays reflected from the signal of the IR sensor 210 is greater than or equal to a predetermined threshold, that is, the stand time corresponding to a walking reactor and an intermediate stand (or late stand). Can be detected.

Acceleration sensor 220 is a sensor for measuring the acceleration of movement when moving and the acceleration of gravity at rest to generate an electrical signal corresponding thereto. While measuring the walking angle with the acceleration sensor 220, it is preferable to use two axes (eg, a gravity direction axis / movement direction axis) as shown in FIG. 6 in consideration of the calculation capability of the controller 110. Although it is possible to detect the angle of the shoe (foot bottom) using one axis (eg, the gravity direction axis), the calculation of the acceleration value into an angle takes longer than the calculation time of detecting the force vectors of the two axes. . Accordingly, the signal processor 230 may detect a time corresponding to the stir stage from the signal of the acceleration sensor 220.

In this way, the walking stand is inferred by measuring the contact time of the ground of the plantar part. The contact is as described above when the IR sensor 210 reflects the infrared rays to the maximum. The threshold setting for determining the maximum value of the reflection amount was set to an average value measured for a certain time before the start of walking (see FIG. 7). The reflection amount measurement of the IR sensor 210 may vary depending on the quality or type of the reflection surface, but it is assumed that the walking is performed on the same reflection surface. The stator STP _time calculated by the signal processor 230 based on the signal of the IR sensor 210 is a reflection amount (signal magnitude of the IR sensor 210) generated within a predetermined timer period as shown in [Equation 1]. ) May be calculated as the sum of predetermined reflectance measurement periods when?

 [Equation 1]

In the signal processor 230, the walking _time for walking is detected by subtracting the standing _time after detecting the walking period GC _time as shown in [Equation 2], [Equation 3], and [Equation 4]. That is, the walking period GC _time may be calculated as the sum of predetermined force vector measurement periods when the force vector scalar amount (signal size of the acceleration sensor 220), which occurs within the period of the predetermined timer, is equal to or greater than a threshold. The force vector scalar amount corresponds to the sum of the magnitudes of the forces in the moving direction and the gravitational axis, that is, the square root of the squares of the magnitudes of the forces in each direction. At this time, since the maximum scalar value of the force vector is different for each walk, the threshold must be variable. In this case, the signal processing unit 230, as shown in [Equation 5], the force vector scalar amount (signal size of the acceleration sensor 220) is The new threshold can be adjusted by reflecting a plurality of variations in the previous force vector scalar amount that is above the threshold. That is, the threshold adjustment may be made by multiplying a plurality of sums of the previous force vector scalar amount whose force vector scalar amount (signal size of the acceleration sensor 220) is greater than or equal to the threshold by a predetermined coefficient α / 10.

As described above, the information on the standing and stir devices measured by the signal processor 230 may be wirelessly transmitted to the walking aid robot according to a communication method such as Zigbee, Bluetooth, etc. through the wireless local area communication module 240. Accordingly, the short-range communication module 130 of the walking aid robot receives information about the walking period, the stance and the stator measured by the signal processor 230, and based on this, the controller 110 may control the motor. .

&Quot; (2) &quot;

&Quot; (3) &quot;

&Quot; (4) &quot;

[Equation 5]

<Sync with walker assistant>

In order to synchronize the walking speed of the user and the moving speed of the walking aid robot, it is necessary to measure the speed of the walking aid robot, and to continuously measure the speed of the walking aid robot if it is faster than the user, and to speed it up if it is slow. This can be done through the PID (Proportional Integral Differential, Proportional Integral Differential) control in the control unit 110 of the walking aid robot, as shown in [Equation 6] the rotation of the wheel M which is a measured value of the encoder provided in the motor 120 _RPS is used for PID control for proper moving speed. Synchronization rate is the SWP _time (walking cycle GC _time , if necessary) in the control unit 110 as shown in [Equation 7] Alternatively, it is possible to control the feedback in a direction without difference by continuously checking the walking speed of the user and the moving speed V _vehicle of the walking assistance robot based on the stator _time . That is, the controller 110 determines a duty ratio of a pulse width modulation (PWM) signal required for driving the motor 120 so that the walking speed of the user and the moving speed of the walking assisting robot are synchronized, and the motor ( By controlling the 120, the wheels mounted on the motor 120 may be rotated according to the walking speed of the user.

[Equation 6]

&Quot; (7) &quot;

Experiment and Results

In order to verify the proposed technique, the following experiments were carried out. The hardware is a gait detection sensor module and a walking aid robot that largely detect the number of walking and the walking period. The walking detection sensor module was attached to the side of the shoe to detect the walking cycle. The detected walking cycle was used as a speed command value to the control unit 110 of the walking aid robot through wireless communication (Bluetooth). The speed detection of the walking aid robot was measured by an encoder mounted on the robot. The measured robot speed was used to detect the synchronization rate between the user and the robot.

The experimental items were selected to walk slowly, walk fast, and assume that the user of the walking aid robot was an elderly person and the use environment was a nursing hospital or silver town. In the experiment, each of the three items was repeated 100 times to detect the coincidence rate of the number of walking detection and the walking cycle. To ensure the accuracy of the experiment, each experiment took a sufficient rest before proceeding. The experimental results are shown in Table 1 below, and the detection of walking averaged 98%.

<Table 1> Number of walking and detection result of walking cycle

As shown in FIG. 7, the force vector scalar amount data of the acceleration sensor 220 was found to include a noise component due to vibration when the plantar part fell off the ground and when it was stuck. 710 is a graph of the IR sensor 210 output, 720 is a scalar amount output graph of the force vector of the acceleration sensor 220. However, since the interval was short, the gait period was detected without filter processing because it was not significantly interfered with the detection of gait. Here, when the plantar portion is in close contact with the floor, the gait can be subdivided into two stages because the division is relatively clear. As a result, it was possible to find a walking cycle suitable for active walking robots.

As for the detection of the synchronization rate between the user and the walking aid robot, the average synchronization rate was 96.67% for the three categories of slow walking, walking and fast walking, as in the detection of walking.

<Table 2> Gait Cycle and Motivation Rate of Gait Assist Robots

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Infra Red (IR) Sensors (210)
Acceleration Sensor (220)
Signal processor 230
Wireless Near Field Communication Module (240)

Claims (5)

In the walking aid robot that assists the user walking in walking aid mode,
A first near field communication module for wirelessly receiving information from a walking detection sensor module attached to a user's shoe; A control unit which determines a moving direction and a moving speed while assisting a user walking, and controls a moving speed using information received from the walking detection sensor module; And a motor for rotating the wheels according to the movement speed control of the control unit.
The gait detection sensor module is an infrared sensor for irradiating infrared rays and generating an electrical signal corresponding to the reflected amount of infrared rays, and generating an electrical signal corresponding to acceleration values in the gravity direction axis and the moving direction axis according to the user's walking. A signal processor detecting a walking period, a standing unit, or a stir of the user based on an acceleration sensor, the infrared sensor and the outputs of the acceleration sensor, and a walking period of the user, the standing unit, or the stinging unit A second short range communication module configured to transmit information to the first short range communication module,
The control unit walks robot, characterized in that for controlling the motor by using the information about the walking period, the stance, or the stance of the user received through the first short-range communication module. The method of claim 1,
The signal processing unit,
The stance detector is detected based on when the output of the infrared sensor is greater than or equal to a threshold, and the force vector scalar amount, which is a sum of the magnitudes of the forces on the gravity direction axis and the movement direction axis, is based on the output of the acceleration sensor. A walking assistance robot, comprising: detecting a walking period of a user, and detecting the stippled device by removing the standing unit from the walking period of the user. The method of claim 1,
And the signal processor is configured to vary the threshold value compared with the force vector scalar amount by reflecting a plurality of variations in the previous force vector scalar amount that is greater than or equal to a threshold value. The method of claim 1,
The control unit may be configured to drive the motor such that the walking speed of the user based on the walking period of the user, the stance device, or the stator and the moving speed of the walking assistance robot based on the measured value of the encoder included in the motor are synchronized. A walk assistance robot, comprising: determining a duty ratio of a required PWM signal and controlling the motor using the corresponding PWM signal. In the walking aid robot operating method for assisting the user walking in walking aid mode,
The gait detection sensor module attached to the user's shoes is used to detect the user's gait period, stand, or stray device based on the output of the infrared sensor and the acceleration sensor, and transmit the detected information through a wireless local area communication method. step; And
Rotating a wheel connected to a motor according to a moving speed control using information on the walking period of the user, the stance device, or the stance device received from the walking detection sensor module in a walking assistance robot;
Method of operation of the walk assistance robot comprising a.

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