Patent Description:
With the onset of rapidly aging societies, an increasing number of people may experience inconvenience and/or pain from joint problems. Thus, there may be a growing interest in walking assistance apparatuses enabling the elderly and/or patients having joint problems to walk with less effort. Further, motion assistance apparatuses increasing muscular strength of users for military purposes are being developed.

A difference between left and right assistance forces for each walking phase, a step length, and a magnitude of a torque in a straight walking period when the user is performing a straight walking operation in a relatively straight line may differ from those in a turning walking period when the user is performing a turning operation. Conventionally, a walking assistance apparatus may not recognize a change from the straight walking operation to the turning walking operation such that the magnitude of the torque in the turning walking period may be controlled to be equal to that in the straight walking period, such that it may be difficult to perform a smooth direction change in the turning walking period.

Document (<CIT>) is directed to a power assisting robotic device and control method thereof. It discloses a power assist robot apparatus which is capable of assisting heavy-object lifting action and walking movement with limited driving sources. Document (<CIT>) discloses conventional motion assisting apparatus.

In accordance with an embodiment of the present invention, a walking assistance apparatus is provided as defined by the appended claims.

In accordance with another embodiment of the present invention, a non-transitory computer-readable medium is provided as defined by appended claims.

Hereinafter, some example embodiments will be described in detail with reference to the accompanying drawings. Regarding the reference numerals assigned to the elements in the drawings, it should be noted that the same elements will be designated by the same reference numerals, wherever possible, even though they are shown in different drawings. Also, in the description of embodiments, detailed description of well-known related structures or functions will be omitted when it is deemed that such description will cause ambiguous interpretation of the present disclosure.

It should be understood, however, that there is no intent to limit this disclosure to the particular example embodiments disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the example embodiments. Like numbers refer to like elements throughout the description of the figures.

In addition, terms such as first, second, A, B, (a), (b), and the like may be used herein to describe components. It should be noted that if it is described in the specification that one component is "connected", "coupled", or "joined" to another component, a third component may be "connected", "coupled", and "joined" between the first and second components, although the first component may be directly connected, coupled or joined to the second component.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

<FIG> and <FIG> illustrate a configuration of a walking assistance apparatus according to at least one example embodiment.

Referring to <FIG> and <FIG>, a walking assistance apparatus <NUM> may assist a walking of a user. The walking assistance apparatus <NUM> may be a wearable device.

Although <FIG> illustrates a hip-type walking assistance apparatus, the type of the walking assistance apparatus <NUM> is not limited thereto. The walking assistance apparatus may support an entire pelvic limb or a portion of a pelvic limb. The walking assistance apparatus may be one of a walking assistance apparatus that supports a portion of a pelvic limb, a walking assistance apparatus that supports up to a knee, a walking assistance apparatus that supports up to an ankle, and a walking assistance apparatus that supports an entire body.

The examples set forth hereinafter may be applicable to the hip-type walking assistance apparatus. However, at least one example embodiment is not limited thereto. The examples may also be applicable to all various types of apparatuses that assist a walking of a user, for example, an active prosthetic leg.

The walking assistance apparatus <NUM> may include a driver <NUM>, a sensor <NUM>, an inertial measurement unit (IMU) sensor <NUM>, and a controller <NUM>.

The driver <NUM> may provide a driving force to a hip joint of the user. The driver <NUM> may be positioned at a right hip portion and/or a left hip portion of the user. In an example, the driver <NUM> may provide the driving force to left and right knee joints and left and right ankle joints, in addition to hip joints of the user. The driver <NUM> may include a motor configured to generate a rotational torque.

The sensor <NUM> may measure an angle of the hip joint of the user during a walking. Information related to the angle of the hip joint sensed by the sensor <NUM> may include an angle of the right hip joint, an angle of the left hip joint, a difference between the angles of the hip joints, and a moving direction of the hip joint. In an example, the sensor <NUM> may measure angles of the left and right knee joints and/or the left and right ankle joints of the user during a walking. For example, the sensor <NUM> may be included in the driver <NUM>.

The sensor <NUM> may include a potentiometer. The potentiometer may sense R-axial and L-axial joint angles and R-axial and L-axial joint angular velocities with respect to a walking motion of the user.

The IMU sensor <NUM> may measure acceleration information and posture information during a walking. The IMU sensor <NUM> may include a tri-axial gyro sensor, and an acceleration sensor. For example, the IMU sensor <NUM> may sense tri-directional, for example, X-axial, Y-axial and Z-axial, accelerations and rotation rates, and tri-directional, for example, roll, pitch and yaw, tilt angles with respect to the walking motion of the user. In this example, an orientation of the IMU sensor <NUM>, that is, a direction that a torso of the user faces when viewed from above a head of the user, may be known through the yaw angle. Hereinafter, the direction that the torso of the user faces will be referred to as a "body yaw angle".

The walking assistance apparatus <NUM> may detect a landing point of a foot of the user based on the acceleration information measured by the IMU sensor <NUM>. A pressure sensor (not shown) may be on a sole of the foot of the user to detect the landing point of the foot of the user.

In addition to the sensor <NUM> and the IMU sensor <NUM>, the walking assistance apparatus <NUM> may further include various sensors, for example, an electromyogram (EMG) sensor, configured to sense a change in a biosignal or a quantity of motion of the user with respect to the walking motion.

The controller <NUM> may include processing circuitry and a memory (not shown). The controller <NUM> may further include a communication device, and communicate with an external device using the communication device.

The processing circuitry may be, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), an Application Specific Integrated Circuit (ASIC), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, or any other device capable of performing operations in a defined manner.

The processing circuitry may be configured, through a layout design or execution of computer readable instructions stored in a memory (not shown), as a special purpose computer to control the driver <NUM> to output an assistance force to assist the walking of the user by recognize a turning walking and adjust at least one control parameter. Therefore, the controller <NUM> may improve the functioning of the walking assistance apparatus <NUM> itself by enabling a smooth turning walking in response to the recognition of the turning walking.

The driver <NUM> may be attached in forward, backward, left and right operating directions of the hip joints to generate a torque to be used to assist the walking, and also attached in forward, backward, left and right operating directions of the knees and/or the ankles. Further, the driver <NUM> may be attached to each of the hip joints, the knees, and/or the ankles. As described above, a plurality of drivers <NUM> may be attached to various body parts that require the assistance force to assist the walking of the user.

For example, in the hip-type walking assistance apparatus <NUM>, two drivers <NUM> may be attached to the left hip and the right hip, and the controller <NUM> may output a control signal to control the driver <NUM> to generate the torque. The driver <NUM> may generate the torque based on the control signal output from the controller <NUM>. The control signal may include, for example, a control parameter, and/or a gain for the control parameter.

In a case in which the magnitude of the torque in the turning walking period is equal to that in the straight walking period, a smooth direction change may be difficult. Therefore, in one or more example embodiments, the controller <NUM> may control the driver <NUM> such that there is a difference between left and right assistance forces and a magnitude of a torque in a straight walking period as compared to those in a turning walking period. For example, to recognize a turning walking and assist the turning walking in response to the recognition of the turning walking, the controller <NUM> may adjust at least one control parameter to enable a smooth turning walking. An example of recognizing the turning walking and adjusting the control parameter will be described further with reference to <FIG>.

<FIG> is a flowchart illustrating a control method for a turning walking according to at least one example embodiment.

Referring to <FIG>, a control apparatus configured to perform turning walking, hereinafter, the "control apparatus", may be the walking assistance apparatus <NUM> described above, or a separate apparatus for a walking assistance apparatus.

In operation <NUM>, the control apparatus may receive sensor information. The sensor information may be sensed from a body part that is relatively close to a torso of a user, for example, a pelvis, an abdomen, a chest, a back or a head, or a body part that performs a few motions, for example, an arm or a leg. Further, the sensor information may be sensed by any one or any combination of a joint sensor such as a joint angle sensor or a joint acceleration sensor, an inertial sensor, an azimuth sensor, a geomagnetic sensor, a pressure sensor, and a foot sole contact sensor. The joint angle sensor may include a resistive sensor, a capacitive sensor, and a polarization sensor.

The sensor information may include, for example, an angle of a hip joint of the user, an angular velocity of the hip joint, an angular acceleration of the hip joint, an angle of a knee joint, an angular velocity of the knee joint, an angular acceleration of the knee joint, an angle of an ankle joint, an angular velocity of the ankle joint, an angular acceleration of the ankle joint, a magnitude of pressure, and data sensed by the inertial sensor.

For example, the controller <NUM> may receive the sensor information from one or more of the sensor <NUM> and the IMU sensor <NUM>.

In operation <NUM>, the control apparatus may recognize a turning walking of the user based on the sensor information. For example, the controller <NUM> may recognize the user is attempting to turn while walking using the sensor data received from one or more of the sensor <NUM> and the IMU sensor <NUM>. An example of the control apparatus recognizing the turning walking of the user will be described further with reference to <FIG>.

In some example embodiments, instead of recognizing the turning walking while the turning walking is happening, the controller <NUM> may receive the sensor information from one or more cameras and/or inertial sensors attached to the head of the user, and predict that the user is going to performing the turning walking based on the sensor information. For example, the user may turn their head and/or eyes in the direction of intended movement at the beginning of the turning walking. The controller <NUM> may detect this walking intention of the user in advance of the user turning to further improve the smoothness of the turning operation.

In operation <NUM>, the control apparatus may adjust at least one control parameter to assist the turning walking. For example, the controller <NUM> may adjust at least one of the control parameters in response to recognizing the turning while walking by determining a gain for the at least one control parameter, and applying the gain to the at least one control parameter, thereby adjusting the control parameter.

In one example, in response to recognition of the turning walking, the control apparatus (e.g., the controller, <NUM>) may reduce all torques of drivers of the control apparatus by multiplying all control parameters by the gain, irrespective of a turning direction. In another example, the control apparatus may recognize the turning direction based on the sensor information, and control the at least one control parameter based on the turning direction. In another example, the control apparatus may recognize a turning degree of the user based on the sensor information, and adjust the at least one control parameter based on the turning degree. The turning degree may include, for example, a rotation angle, and/or a rotation angular velocity. In still another example, the control apparatus may adjust the gain for the at least one control parameter based on the turning degree. Examples of the control apparatus adjusting the gain will be described further with reference to <FIG>.

The control parameter may include, for example, a hip joint torque for each walking phase, an ankle joint torque for each walking phase, a knee joint torque for each walking phase, and a foot sole torque for each walking phase. Walking phases will be described in detail with reference to <FIG>. Further, examples of the control apparatus adjusting the control parameter will be described further with reference to <FIG>.

In some example embodiments, the adjustment amount of the gain γ may be based on individual parameters associated with the user. For example, the controller <NUM> may recognize a weight of the user and set the gain to an appropriate level based on the individual parameters. For example, the gain may be initially set based on a reference model, the controller <NUM> may measure the weight of the user using sensors or may receive input of the same from the user, and may adjust the amount of gain proportional to the excess amount of weight associated with the user beyond the weight associated with a reference model.

<FIG> is a flowchart illustrating an example of recognizing a turning walking according to at least one example embodiment, and <FIG> is a graph illustrating a change in a variable component during a walking of a user according to at least one example embodiment.

Referring to <FIG> and <FIG>, in operation <NUM>, the control apparatus may track a variable component that varies in response to a walking, based on sensor information. In a graph <NUM> of <FIG>, a variable component may indicate a direction that a torso of a user faces during the walking, that is, a body yaw angle, or a direction that a pelvis of the user faces during the walking. The control apparatus may determine whether the user is performing a turning walking based on the variable component.

In operation <NUM>, the control apparatus may extract a representative component from the variable component. For example, the controller <NUM> may read, from the graph <NUM> of <FIG>, values θ1 and θ3 at instances at which the variable component, that is, the body yaw angle, is minimized, for example, times t1 and t3, and values θ2 and θ4 at instances at which the variable component is maximized, for example, times t2 and t4, and extracts median values θ<NUM>, θ<NUM>, θ<NUM>,. thereof as representative components.

In operation <NUM>, the control apparatus may determine whether a variance in the representative component exceeds a desired (or, alternatively, a predetermined) range. For example, the controller <NUM> may update the median values θ<NUM>, θ<NUM>, θ<NUM>,. in the graph <NUM> of <FIG>, and identify an i-th change Δθi = θi - θi-<NUM> of each median value per step by comparing the corresponding median value to a previous median value. In this example, the i-th change Δθi of each median value per step may correspond to a variance in the representative component.

In response to determining that the variance in the representative component exceeds the desired (or, alternatively, the predetermined) range, in operation <NUM>, the control apparatus may determine that the user is performing a turning walking. For example, in a case in which θ* denotes the desired (or, alternatively, the predetermined) range or a threshold, the controller <NUM> may determine that the user is performing a turning walking if |Δθi| > θ*.

In response to determining that the variance in the representative component is maintained within the desired (or, alternatively, the predetermined) range, in operation <NUM>, the control apparatus may determine that the user is performing a straight walking. For example, if |Δθi| ≤ θ*, the controller <NUM> may determine that the user is performing a straight walking. In this example, the desired (or, alternatively, the predetermined) range or threshold may be determined empirically through experimentation.

In response to determining that the user is performing a turning walking, the control apparatus may determine a turning direction to be left or right based on a sign of Δθi. For example, in a case in which the body yaw angle is defined to increase in response to a left turning, the controller <NUM> may determine the turning direction to be left ifΔθi > <NUM>, and determine the turning direction to be right if Δθi < <NUM>.

<FIG> is a flowchart illustrating an example of recognizing a turning walking according to at least one example embodiment.

Referring to <FIG>, in operation <NUM>, the control apparatus may track a first variable component and a second variable component that vary in response to a walking, based on sensor information. For example, the first variable component may correspond to a motion of a left joint of a user, and the second variable component may correspond to a motion of a right joint of the user.

The control apparatus may recognize whether the user is performing a turning walking by determining whether a variance in the first variable component and a variance in the second variable component are symmetric.

For example, in operation <NUM>, the controller <NUM> may determine whether the variance in the first variable component and the variance in the second variable component are asymmetric. In response to determining that the variance in the first variable component and the variance in the second variable component are asymmetric, in operation <NUM>, the controller <NUM> may determine that the user is performing a turning walking. Likewise, in response to determining that the variance in the first variable component and the variance in the second variable component are not asymmetric, that is, the variance in the first variable component and the variance in the second variable component are symmetric, in operation <NUM>, the controller <NUM> may determine that the user is performing a straight walking.

For example, in a case in which the user is performing a left turning walking, a left leg of the user on an inner side of a turning direction may relatively narrow a step length in comparison to a right leg on an outer side of the turning direction, thereby enabling a smooth turning walking. In a case in which the user is performing a right turning walking, the right leg of the user on an inner side of a turning direction may relatively narrow a step length in comparison to the left leg on an outer side of the turning direction. By differing a step length of one leg as described above, there may arise a difference between the variance in the first variable component and the variance in the second variable component. The control apparatus may distinguish between a turning walking and a straight walking based on an asymmetry between the variance in the first variable component and the variance in the second variable component.

<FIG> illustrate examples of determining a gain for a control parameter according to at least one example embodiment.

In a case of determining a torque to assist a turning walking, a degree of a straight walking and a degree of a turning walking may be expressed using a gain for a control parameter, without distinguishing between the straight walking and the turning walking. The gain may have a value of a real number greater than or equal to "<NUM>" and less than or equal to "<NUM>". The torque may be continuously adjusted using the gain based on whether a user is performing a straight walking or a turning walking.

To assist the turning walking, the control apparatus may determine a gain γ with respect to a torque calculated in a turning walking period, and apply the gain to a control parameter. The control apparatus may determine the gain to change based on a variance Δθi in a representative component of the tracked variable component.

Referring to <FIG>, in a graph of <FIG>, a first threshold with respect to the variance Δθi in the representative component may be ±a, and a second threshold may be ±b. In this example, the first threshold may correspond to a variance, for example, ±<NUM> degrees, which may be regarded as a straight walking, and the second threshold may correspond to a variance which may be regarded as a turning walking.

If the variance Δθi in the representative component is within ±a, the control apparatus may determine the gain γ to be "<NUM>". If the variance Δθi in the representative component exceeds ±b, the control apparatus may determine the gain γ to be "<NUM>".

If the variance Δθi in the representative component is in remaining regions, for example, a region in which the variance Δθi in the representative component is greater than -b and less than -a, and a region in which the variance Δθi in the representative component is greater than a and less than b, the control apparatus may determine the gain γ to be a linear value between "<NUM>" and "<NUM>" such that the gain γ may not change suddenly.

Referring to <FIG>, in a graph of <FIG>, if the variance Δθi in the representative component is within ±a, the control apparatus may determine the gain γ to be "<NUM>". In addition, if the variance Δθi in the representative component exceeds ±a, the control apparatus may determine the gain γ to be "<NUM>".

Referring to <FIG>, in a graph of <FIG>, if the variance Δθi in the representative component is within ±a, the control apparatus may determine the gain γ to be "<NUM>". If the variance Δθi in the representative component exceeds ±a, the control apparatus may determine the gain γ to be a value that gently decreases from "<NUM>" to "<NUM>".

Referring to <FIG>, in a graph of <FIG>, if the variance Δθi in the representative component is within ±a, the control apparatus may determine the gain γ to be "<NUM>". If the variance Δθi in the representative component exceeds ±b, the control apparatus may determine the gain Y to be "<NUM>". If the variance Δθi in the representative component is in remaining regions, for example, a region in which the variance Δθi in the representative component is greater than -b and less than -a, and a region in which the variance Δθi in the representative component is greater than a and less than b, the control apparatus may determine the gain γ to be "<NUM>".

<FIG> illustrates a relationship among a variable component, a variance in the variable component, and a gain in a turning walking period with respect to a turning walking according to at least one example embodiment.

Referring to <FIG>, a graph <NUM> may show a change in a pelvis yaw angle θi with respect to a turning walking of a user or a median value θi of a pelvis yaw angle determined from a value at an instant at which the pelvis yaw angle is maximized and a value at an instant at which the pelvis yaw angle is minimized. In the graph <NUM>, a period during which the value θi changes, for example, a period between <NUM> seconds and <NUM> seconds, may correspond to a turning walking period.

A graph <NUM> may show a rotation per step Δθi. The rotation per step may correspond to a rate of change in the pelvis yaw angle θi or the medium value θi of the pelvis yaw angle. For example, the rotation per step may be close to "<NUM>" in a straight walking period, and increase to "<NUM>" or higher in a turning walking period.

In this example, a value of a gain γ, which is a parameter to determine whether a user is performing a turning walking, is represented in a graph <NUM>. In the graph <NUM>, the gain γ may be maintained at "<NUM>" in the straight walking period, and may decrease when the rotation per step increases to be greater than or equal to a desired (or, alternatively, a predetermined) value, for example, <NUM> degrees.

In response to recognition of a turning walking, the control apparatus (e.g., the controller <NUM>) may reduce a magnitude of a torque by multiplying all control parameters by the gain, thereby enabling a smoother torque control and a smoother direction change in the turning walking period.

<FIG> is a flowchart illustrating an example of controlling a walking assistance apparatus according to at least one example embodiment.

Referring to <FIG>, in operation <NUM>, a walking assistance apparatus (e.g., the controller <NUM>) may acquire sensor information θt from an IMU sensor (e.g., the IMU sensor <NUM>).

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine whether the sensor information θt is a smallest value of pieces of sensor information. In response to determination that the sensor information θt is a smallest value, in operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine the sensor information θt to be a minimum value θmin.

In response to determining that the sensor information θt is not a smallest value of the pieces of sensor information, in operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine whether the sensor information θt is a greatest value of the pieces of sensor information. In response to determining that the sensor information θt is not a greatest value of the pieces of sensor information, in operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine at least one control parameter. In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may control the walking assistance apparatus using the at least one control parameter.

In response to determining that the sensor information θt is a greatest value of the pieces of sensor information, in operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine the sensor information θt to be a maximum value θmax.

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may set a previous rate of change θprev based on a current rate of change θnow in the sensor information. In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine a mean value of the minimum value θmin and the maximum value θmax to be the current rate of change θnow.

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may calculate a difference Δθ between the current rate of change θnow and the previous rate of change θprev.

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may calculate a gain γ corresponding to Δθ. For example, the walking assistance apparatus may calculate the gain γ corresponding to Δθ using the methods described through <FIG>.

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may determine at least one control parameter by applying the calculated gain.

In operation <NUM>, the walking assistance apparatus (e.g., the controller <NUM>) may control the walking assistance apparatus using the at least one control parameter.

<FIG> illustrates transitions between walking phases according to at least one example embodiment.

Referring to <FIG>, walking motions <NUM>, <NUM>, <NUM> and <NUM> of a user during a walking, and walking phases <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> are illustrated.

During a walking, a left leg and a right leg may move symmetrically, and thus the left leg and the right leg may have the same or similar walking cycles. For example, a walking cycle may be defined as a cycle from an instant at which a first leg is in contact with the ground to an instant at which the first leg is in contact with the ground again.

The walking motions <NUM>, <NUM>, <NUM> and <NUM> may be motions in a walking cycle of the left leg.

The walking motion <NUM> may correspond to the right hip joint stance phase <NUM>, and the walking motion <NUM> may correspond to the left hip joint swing phase <NUM>. The walking motion <NUM> may correspond to the right ankle push-off phase <NUM>, and the walking motion <NUM> may correspond to the left hip joint stance phase <NUM>.

A "swing phase" refers to a state of a first leg moving a predetermined angle forward in a walking cycle. A "stance phase" refers to a state of the first leg being in contact with the ground and supporting a body in the walking cycle. For example, a swing phase torque may correspond to a flexion torque in a direction in which a joint bends, and a stance phase torque may correspond to an extension torque in a direction in which a joint stretches.

During a walking, an ankle of a user may perform a dorsi-flexion motion or a plantar-flexion motion about an ankle joint. The dorsi-flexion motion may correspond to a motion of pulling the ankle in a direction toward a top of a foot, and the plantar-flexion motion may correspond to a motion of pushing the ankle in a direction toward a heel, that is, a motion of pushing the ground. A "push-off phase" refers to a state of an ankle of a second leg generating a pushing torque after the swing phase of the first leg. A push-off phase torque may correspond to a foot sole plantar flexion torque. In an example, an ankle joint may be controlled in view of the push-off phase performed in response to the dorsi-flexion motion.

According to a walking mechanism, a walking state when a walking is initiated may differ. However, walking phases including motions of hip joints and ankle joints may transition, for example, in an order of the right hip joint stance phase <NUM>, the left hip joint swing phase <NUM>, the right ankle push-off phase <NUM>, the left hip joint stance phase <NUM>, the right hip joint swing phase <NUM>, and the left ankle push-off phase <NUM>. The walking phases may also be referred to as "walking states.

In an example, the control apparatus (e.g., the controller <NUM>) may recognize a swing phase, a stance phase, and a push-off phase in the following manner.

For example, if pressures measured by pressure sensors are less than or equal to a desired (or, alternatively, a preset) pressure, the control apparatus may determine that a walking state of a user is a swing phase. In this example, the pressure sensors may be positioned at significant portions at which a sole of a foot of the user presses a shoe insole. The pressure sensors may include a forefoot sensor configured to sense a pressure at a ball of the foot of the user, and a rearfoot sensor configured to sense a pressure at a heel of the user.

If the pressures measured by the pressure sensors exceed the desired (or, alternatively, the preset) pressure, the control apparatus(e.g., the controller <NUM>) may determine that the walking state of the user is a stance phase.

In response to determining that the walking state of the user is a stance phase, the control apparatus (e.g., the controller <NUM>) may determine whether the user is to perform a push-off motion based on the pressures measured by the forefoot sensor and the rearfoot sensor. In response to determining that the user is to perform the push-off motion, the control apparatus(e.g., the controller <NUM>) may adjust a torque to assist a push-off phase at an appropriate point in time.

<FIG> is a flowchart illustrating an example of adjusting a control parameter according to at least one example embodiment.

As described above, for a smooth turning walking, a step length of a left leg may decrease during a left turning walking, and a step length of a right leg may decrease during a right turning walking. A control apparatus (e.g., the controller <NUM>) may recognize a turning direction of a user during a turning walking and adjust control parameters based on the turning direction.

When the turning direction of the user is recognized as left, the control apparatus (e.g., the controller <NUM>) may reduce a left step length to easily perform the turning walking. Further, when the turning direction of the user is recognized as right, the control apparatus (e.g., the controller <NUM>) may reduce a right step length to easily perform the turning walking.

To reduce the left step length, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque of a left hip joint, and/or reduce a stance phase torque of a right hip joint. To reduce the right step length, the control apparatus (e.g., the controller <NUM>) may reversely perform the operation of reducing the left step length. For example, the control apparatus may reduce a magnitude of the torque by multiplying the torque by a gain.

The control operation with respect to the left and right hip joints of the user for the turning walking may be arranged as shown in Table <NUM>.

Referring to <FIG>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may determine whether a variance in a representative component or a variance in a variable component satisfies Δθi > <NUM>. The control apparatus may recognize a turning direction based on a z-axial rotation angle of a body part from which sensor information is obtained. For example, if Δθi > <NUM>, the control apparatus may recognize the turning direction as left. If Δθi ≤ <NUM>, the control apparatus may recognize the turning direction as right.

In response to determining that the turning direction is left, that is, Δθi > <NUM>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τleft,swing of a left hip joint of a user and/or reduce a stance phase torque τright,stance of a right hip joint of the user by applying a gain Y.

In response to determining that the turning direction is right, that is, Δθi ≤ <NUM>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τright,swing of the right hip joint of the user and/or reduce a stance phase torque τleft,stance of the left hip joint of the user by applying the gain Y.

Here, the gain Y may be used to reduce a step length of a turning direction. A gain to be used to reduce the swing phase torques of the left/right hip joints may be equal to or different from a gain to be used to reduce the stance phase torques of the left/right hip joints.

In a case of reducing a left step length, the control apparatus may reduce a step length of a left hip joint by reducing a push-off phase torque of an ankle joint of a right leg supporting a body, that is, the right ankle joint. Further, in a case of reducing a right step length, the control apparatus may reduce a step length of a right hip joint by reducing a push-off phase torque of an ankle joint of a left leg, that is, the left ankle joint. The control operation with respect to the left and right ankle joints of a user for a turning walking may be arranged as shown in Table <NUM>.

To assist the turning walking, the control apparatus may adjust a hip joint torque for each walking phase and an ankle joint torque for each walking phase together, as shown in <FIG>.

Referring to <FIG>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may determine whether a variance in a representative component or a variance in a variable component satisfies Δθi > <NUM>. For example, if Δθi > <NUM>, the control apparatus may recognize a turning direction as left. If Δθi ≤ <NUM>, the control apparatus may recognize the turning direction as right.

In response to determining that the turning direction is left, that is, Δθi > <NUM>, , in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τleft,swing of a left hip joint of a user and/or reduce a stance phase torque τright,stance of a right hip joint of the user by applying a gain Y. In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a push-off phase torque τright,plantar of a right ankle joint of the user by applying the gain Y.

In response to determining that the turning direction is right, Δθi ≤ <NUM>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τright,swing of the right hip joint of the user and/or reduce a stance phase torque τleft,stance of the left hip joint of the user by applying the gain Y. In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a push-off phase torque τleft,planter of a left ankle joint of the user by applying the gain Y.

Here, the gain Y may be used to reduce a step length of a turning direction. A gain to be used to reduce the stance phase torques of the left/right hip joints, a gain to be used to reduce the swing phase torques of the left/right hip joints, and a gain to be used to reduce the push-off phase torques of the left/right ankle joints may be equal to or different from each other.

In an example, a method of controlling a torque for each walking phase of the hip joints and the ankle joints of the left and right legs to reduce a left or right step length may be arranged as shown in Table <NUM>.

A relationship among the gain and the torques of the left and right joints in a case of adjusting the control parameter for a left turning walking based on the example of <FIG> will be described with reference to <FIG>.

<FIG> is a flowchart illustrating an example of adjusting a control parameter according to at least one example embodiment. In general, during a turning walking, a walking speed and a step length decrease in comparison to a straight walking. Reflecting the foregoing, the control apparatus may reduce a torque by multiplying all control parameters by a gain for each turning walking.

Referring to <FIG>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τleft,swing of a left hip joint of a user and/or reduce a stance phase torque τright,stance of a right hip joint of the user by applying a gain Y, in response to recognition of a turning walking of the user.

In operation <NUM>, the control apparatus(e.g., the controller <NUM>) may reduce a swing phase torque τright,swing of the right hip joint of the user and/or reduce a stance phase torque τleft,stance of the left hip joint of the user by applying the gain Y.

Referring to <FIG>, in operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τleft,swing of a left hip joint of a user by applying a gain Y1, and/or reduce a stance phase torque τright,stance of a right hip joint of the user by applying a gain Y2 in response to recognition of a turning walking of the user.

In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a swing phase torque τright,swing of the right hip joint of the user by applying the gain Y1, and/or reduce a stance phase torque τleft,stance of the left hip joint of the user by applying the gain Y2.

Here, the gain Y1 and the gain Y2 may be used to reduce an overall speed during the turning walking, and may be, for example, "<NUM>".

In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may determine whether a variance in a representative component or a variance in a variable component satisfies Δθi > <NUM>. For example, if Δθi > <NUM>, the control apparatus may recognize a turning direction as left. If Δθi ≤ <NUM>, the control apparatus may recognize the turning direction as right.

In response to determining that the turning direction is left, that is, Δθi > <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce the swing phase torque τleft,swing of the left hip joint of the user and/or reduce the stance phase torque τright,stance of the right hip joint of the user by applying a gain Y3, in operation <NUM>. In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a push-off phase torque τright,plantar of a right ankle joint of the user by applying a gain Y4.

In response to determining that the turning direction is right, that is, Δθi ≤ <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce the swing phase torque τright,swing of the right hip joint of the user and reduce the stance phase torque τleft,stance of the left hip joint of the user by applying the gain Y3, in operation <NUM>. In operation <NUM>, the control apparatus (e.g., the controller <NUM>) may reduce a push-off phase torque τleft,plantar of a left ankle joint of the user by applying the gain γ<NUM>.

The gain Y3 and the gain Y4 may be used to reduce a step length of a turning direction, and may be, for example, "<NUM>".

<FIG> illustrates a relationship among a gain and torques of left and right joints during a left turning walking according to at least one example embodiment.

Referring to <FIG>, a relationship among a gain and torques of left and right joints in a case of adjusting a control parameter for a left turning walking based on the example of <FIG> is illustrated.

A graph <NUM> shows a swing phase torque and a stance phase torque of a left hip joint of a user, and a graph <NUM> shows a push-off phase torque of a left ankle joint of the user during a straight walking. In addition, a graph <NUM> shows a swing phase torque and a stance phase torque of a right hip joint of the user, and a graph <NUM> shows a push-off phase torque of a right ankle joint of the user during a turning walking. A graph <NUM> shows a change in a gain in response to a walking of the user.

For example, in a case in which the user performs a straight walking, the control apparatus (e.g., the controller <NUM>) may maintain level of the gain. Thus, the torques shown in the graphs <NUM> through <NUM> may be the same values having constancy in response to a transition of a walking cycle or a walking phase.

As shown in the graph <NUM>, the control apparatus (e.g., the controller <NUM>) may gradually reduce the gain in a left turning period marked using broken lines. In this example, the control apparatus may gradually reduce the swing phase torque of the left hip joint as indicated using a broken line on a lower side of the graph <NUM>. In addition, the control apparatus may gradually reduce the stance phase torque of the right hip joint as indicated using a broken line on an upper side of the graph <NUM>, and also reduce the push-off phase torque of the right ankle joint as indicated using a broken line on an upper side of the graph <NUM>, thereby enabling the user to perform a smooth left turning walking.

The control apparatus may gradually reduce a decrement in the gain in response to gradually entering a straight walking period from the turning walking period, thereby adjusting the torques to be suitable for a walking in the straight period.

<FIG> illustrates a relationship among a gain and torques of left and right joints during a left turning walking according to at least one example embodiment. Referring to <FIG>, a relationship among a gain and torques of left and right joints in a case of adjusting a control parameter for a left turning walking based on the example of <FIG> is illustrated.

A graph <NUM> shows a swing phase torque and a stance phase torque of a left hip joint of a user, and a graph <NUM> shows a swing phase torque and a stance phase torque of a right hip joint of the user. A graph <NUM> shows a change in a gain in response to a walking of the user.

For example, in a case in which the user performs a straight walking, the control apparatus(e.g., the controller <NUM>) may maintain a level of the gain. Thus, the torques shown in the graphs <NUM> and <NUM> may be the same values having constancy in response to a transition of a walking cycle or a walking phase.

On the contrary, as shown in the graph <NUM>, the control apparatus (e.g., the controller <NUM>) may gradually reduce the gain in a left turning walking period marked using broken lines. In this example, the control apparatus may gradually reduce the stance phase torque and the swing phase torque of the left hip joint as indicated using broken lines on an upper side and a lower side of the graph <NUM>. In addition, the control apparatus (e.g., the controller <NUM>) may gradually reduce the stance phase torque and the swing phase torque of the right hip joint as indicated using broken lines on an upper side and a lower side of the graph <NUM>.

The control apparatus may reduce an overall walking speed by reducing a torque for each walking phase of all joints in a turning walking period, thereby adjusting torques to enable a smooth walking in the turning walking period.

The control apparatus (e.g., the controller <NUM>) may gradually reduce a decrement in the gain in response to gradually entering a straight walking period from the turning walking period, thereby adjusting the torques to be suitable for a walking in the straight period.

<FIG> is a block diagram illustrating a control apparatus for a turning walking according to at least one example embodiment.

Referring to <FIG>, a control apparatus <NUM> may include a joint sensor <NUM>, an inertial sensor <NUM>, and processing circuitry <NUM>.

The joint sensor <NUM> may include a joint angle sensor configured to measure an angle and/or an angular velocity of a joint of a user. For example, the joint of the user may include a hip joint, a knee joint, and an ankle joint. The joint angle sensor may include a hip joint angle sensor, a knee joint angle sensor, and an ankle joint angle sensor.

The inertial sensor <NUM> may sense tri-directional, for example, X-axial, Y-axial and Z-axial, accelerations and rotation rates, and tri-directional, for example, roll, pitch and yaw, tilt angles with respect to a walking motion of the user. The inertial sensor <NUM> may measure a direction that a torso of the user faces, that is, an orientation of the torso of the user, through a yaw angle.

The processing circuitry <NUM> may be included in, for example, the controller <NUM>.

The processing circuitry <NUM> may be, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), an Application Specific Integrated Circuit (ASIC), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, or any other device capable of performing operations in a defined manner.

The processing circuitry <NUM> may be configured, through a layout design or execution of computer readable instructions stored in a memory (not shown), as a special purpose computer to perform the functions of an assistance torque calculator <NUM>, a turning walking recognizer <NUM>, and an assistance torque adjuster <NUM>.

The assistance torque calculator <NUM> may measure a joint angle of the user and calculate a torque to assist a walking of the user based on the joint angle. Further, the assistance torque calculator <NUM> may obtain a walking cycle based on the joint angle and/or a transition among a desired (or, alternatively, a predetermined) number of walking states, and calculate the torque based on the walking cycle.

The turning walking recognizer <NUM> may recognize a turning walking of the user based on sensor information collected by the joint sensor <NUM> and the inertial sensor <NUM>.

The turning walking recognizer <NUM> may track a variable component that varies in response to a walking, based on the sensor information, and determine whether the user is performing a turning walking based on the variable component. The turning walking recognizer <NUM> may extract a representative component from the variable component, and determine whether a variance in the representative component is maintained within a desired (or, alternatively, a predetermined) range. In response to determining that the variance exceeds the desired (or, alternatively, the predetermined) range, the turning walking recognizer <NUM> may determine that the user is performing a turning walking.

In another example, the turning walking recognizer <NUM> may determine whether a variance in a first variable component corresponding to a motion of a left hip joint of the user and a variance in a second variable component corresponding to a motion of a right hip joint of the user is symmetric. In response to determining that the variance in the first variable component and the variance in the second variable component are asymmetric, the turning walking recognizer <NUM> may determine that the user is performing a turning walking.

The turning walking recognizer <NUM> may recognize a turning degree of the user based on the sensor information. In this example, the assistance torque adjuster <NUM> may adjust at least one control parameter or a gain for the at least one control parameter based on the turning degree.

To assist a turning walking, the assistance torque adjuster <NUM> may determine the gain for the at least one control parameter, and adjust the calculated torque by applying the gain to the at least one control parameter. The control parameter may include, for example, any one or any combination of a hip joint torque for each walking phase, an ankle joint torque for each walking phase, a knee joint torque for each walking phase, and a foot sole torque for each walking phase.

The assistance torque adjuster <NUM> may recognize a turning direction of the user based on the sensor information, and adjust the torque by adjusting the at least one control parameter based on the turning direction.

When the turning direction is left, the assistance torque adjuster <NUM> may reduce a swing phase torque of a left hip joint of the user, and reduce a stance phase torque of a right hip joint of the user. When the turning direction is right, the assistance torque adjuster <NUM> may reduce a stance phase torque of the left hip joint of the user, and reduce a swing phase torque of the right hip joint of the user.

When the turning direction is left, the assistance torque adjuster <NUM> may reduce a push-off phase torque of a right ankle joint of the user. When the turning direction is right, the assistance torque adjuster <NUM> may reduce a push-off phase torque of a left ankle joint of the user.

Referring to <FIG>, a control apparatus <NUM> may include sensors <NUM>, a processor <NUM>, a memory <NUM>, and a communication interface <NUM>. The sensors <NUM>, the processor <NUM>, the memory <NUM>, and the communication interface <NUM> may communicate with each other through a communication bus <NUM>.

The sensors <NUM> may include various sensors such as a pressure sensor, in addition to the joint sensor <NUM> and the inertial sensor <NUM> of <FIG>.

The processor <NUM> may recognize a turning walking of a user based on sensor information, and adjust at least one control parameter to assist the turning walking. The processor <NUM> may perform all the operations of the processor <NUM> of <FIG>, and also perform the at least one method described with reference to <FIG> or an algorithm corresponding to the at least one method.

The processor <NUM> may be a hardware-implemented data processing device having a circuit with a physical structure to perform desired operations. For example, the desired operations may include codes or instructions included in a program. The hardware-implemented data processing device may include a microprocessor, a central processing unit (CPU), a processor core, a multi-core processor, a multiprocessor, an application-specific integrated circuit (ASIC), and a field programmable gate array (FPGA).

The processor <NUM> may execute the program, and control the control apparatus <NUM>. The codes included in the program executed by the processor <NUM> may be stored in the memory <NUM>.

The memory <NUM> may include at least one of a volatile memory, non-volatile memory, random access memory (RAM), a flash memory, a hard disk drive, and an optical disk drive.

The control apparatus <NUM> may receive the sensor information through the communication interface <NUM>. In an example, the communication interface <NUM> may receive the sensor information from other sensors existing outside the control apparatus <NUM>.

The units and/or modules described herein may be implemented using hardware components and software components. For example, the hardware components may include microphones, amplifiers, band-pass filters, audio to digital convertors, and processing devices. A processing device may be implemented using one or more hardware device configured to carry out and/or execute program code by performing arithmetical, logical, and input/output operations. The processing device(s) may include a processor, a controller and an arithmetic logic unit, a digital signal processor, a microcomputer, a field programmable array, a programmable logic unit, a microprocessor or any other device capable of responding to and executing instructions in a defined manner. The processing device may run an operating system (OS) and one or more software applications that run on the OS. The processing device also may access, store, manipulate, process, and create data in response to execution of the software. For purpose of simplicity, the description of a processing device is used as singular; however, one skilled in the art will appreciated that a processing device may include multiple processing elements and multiple types of processing elements. For example, a processing device may include multiple processors or a processor and a controller. In addition, different processing configurations are possible, such as parallel processors.

Claim 1:
A walking assistance (<NUM>) apparatus, comprising:
a sensor (<NUM>) configured to obtain sensor information; and
a processor (<NUM>) configured to perform the following steps of:
determining, based on the sensor information, that a user is performing a turning walking operation determining a turning direction associated with the turning walking operation; and
adjusting at least one control parameter based on the determined turning direction to assist the turning operation, wherein said adjusting of the at least one control parameter comprises the steps of:
when the turning direction is left, one or more of:
reducing a swing phase torque of a left hip joint of the user and reduce a stance phase torque of a right hip joint of the user; and
reducing a push-off phase torque of a right ankle joint of the user; and when the turning direction is right, one or more of:
reducing a stance phase torque of a left hip joint of the user and reduce a swing phase torque of a right hip joint of the user; and
reducing a push-off phase torque of a left ankle joint of the user.