JP7483597B2 - Wearable Robot - Google Patents

Description

The present invention relates to a wearable robot.

In recent years, with the declining birthrate and aging population, efforts are being made to reduce the burden on humans at construction sites by introducing robots. For example, Patent Document 1 discloses a screw-driving robot and a ceiling panel transport robot that install ceiling panels. Patent Document 2 discloses a robot device that is composed of a cart-type mobile robot with a multi-joint arm attached, and that performs interior work such as driving screws into ceiling panels.

JP 2012-11653 A Japanese Patent Application Laid-Open No. 5-321454

However, because construction sites involve a variety of environments, there are tasks that are difficult for the conventional robotic devices disclosed in Patent Documents 1 and 2 to perform. Furthermore, at construction sites, it is effective in utilizing robotic devices to enable people and robots to coexist and work together, such as by working together or sharing tasks. To enable people and robots to work together, it is also effective to have an arm-type robot attached to the human body.

When a robot is attached to a human body, the robot will be displaced if the human body tilts. This makes it necessary to correct the robot's posture in accordance with the tilt of the human body. If the amount of correction to the robot's posture is relatively large, the change in the robot's movement will be relatively large. As a result, the force acting on the human body will be relatively large, reducing the stability of the human body.

The present invention aims to solve the above-mentioned problems and to prevent a decrease in the stability of the human body in a wearable robot.

To achieve the above objective, the wearable robot of the present invention comprises a multi-joint arm attached to the human body, a sensor for detecting the posture of the multi-joint arm, and a control device for correcting the tip position of the multi-joint arm. The control device determines whether the human body has swung based on the detection result of the sensor, and if it is determined that the human body has swung, estimates the degree of effect that correction of the tip position of the multi-joint arm will have on the human body, and if the estimated degree of effect is less than a predetermined value, corrects the tip position of the multi-joint arm.

The wearable robot of the present invention can prevent the deterioration of the stability of the human body.

1 is a schematic diagram of a wearable robot according to a first embodiment of the present invention; Block diagram of wearable robot FIG. 2 is a diagram showing a state in which the human body is tilted in the wearable robot shown in FIG. Flowchart of a program executed by the control device Block diagram of a wearable robot according to a second embodiment of the present invention. Enlarged view of the articulated arm Enlarged view of the articulated arm Flowchart of a program executed by the control device

First Embodiment
A wearable robot according to a first embodiment of the present invention will be described below with reference to the drawings. In the following description, the upper and lower sides in FIG. 1 are respectively above and below the wearable robot 1.

The wearable robot 1 is a robot that works in collaboration with humans. As shown in FIG. 1, the wearable robot 1 includes a mounting unit 10, an articulated arm 20, a sensor 30, a camera 40, and a control device 50.

The attachment part 10 is for fixing the multi-joint arm 20 to the user's body H. The attachment part 10 is configured to be detachable from the human body H. The attachment part 10 includes a backpack part 11 and a plurality of belts 12. The backpack part 11 is formed in a rectangular parallelepiped shape, and is attached by being carried on the human body H. The plurality of belts 12 are for fixing the backpack part 11 to the human body H. In this embodiment, the number of belts 12 is two, but it goes without saying that this is not limited to this. The multi-joint arm 20 is attached to the upper side of the backpack part 11.

The multi-joint arm 20 is a manipulator. The multi-joint arm 20 includes a base 21, multiple links 22, 23, and 24, multiple joints J, a hand 25, multiple drive units M, and multiple angle detection units E.

Note that, although the number of joints J shown in FIG. 1 is four, and the number of drive units M and angle detection units E is five, it goes without saying that this is not limited to this. In this embodiment, the first to third joints J1 to J3 each have one axis. Furthermore, the fourth joint J4 has two axes that are perpendicular to each other. Thus, the multi-joint arm 20 has five degrees of freedom, but it goes without saying that the degrees of freedom are not limited to this.

The base 21 is attached to the upper surface of the backpack 11. A first end of a first link 22 is connected to the base 21 via a first joint J1. The first joint J1 operates to rotate the first link 22 around one axis relative to the base 21.

The second end of the first link 22 is connected to the first end of the second link 23 via the second joint J2. The second joint J2 operates to rotate the second link 23 around one axis relative to the first link 22.

The second end of the second link 23 is connected to the first end of the third link 24 via the third joint J3. The third joint J3 operates to rotate the third link 24 around one axis relative to the second link 23.

The hand 25 is connected to the second end of the third link 24 via a fourth joint J4. The fourth joint J4 operates to rotate the hand 25 relative to the third link 24 around two mutually perpendicular axes.

The hand 25 grasps the workpiece for the target task. The target task is, for example, lifting a ceiling panel at a construction site. The workpiece is, for example, a ceiling panel.

The multiple drive units M are disposed at each joint J and rotate the members connected to each joint J around an axis. The multiple drive units M are controlled by the control device 50 and operate each joint J and thus the multi-joint arm 20. The drive units M are, for example, motors.

Multiple angle detection units E are arranged on each drive unit M and detect the rotation angle of each drive unit M. The rotation angle of each drive unit M corresponds to the joint angle of each joint unit J.

The sensor 30 is disposed on the base 21 and detects the posture of the multi-joint arm 20. The posture of the multi-joint arm 20 is the angle of the multi-joint arm 20 with respect to the vertical direction, specifically, the angle C at which the base 21 is tilted with respect to the vertical direction with a reference point P disposed on the base 21 as the origin (Figure 3). The sensor 30 detects the amount of change in angle per unit time, i.e., the angular velocity. The sensor 30 is, for example, a gyro sensor. The sensor 30 may also be a gravity sensor, i.e., an acceleration sensor that detects the angle with respect to the vertical direction. The detection result of the sensor 30 is transmitted to the control device 50.

The camera 40 is placed on the base 21 and captures images of the work area where the desired work is to be performed. The images captured by the camera 40 are transmitted to the control device 50.

The control device 50 is a computer that provides overall control of the wearable robot 1. The control device 50 controls the operation of the multi-joint arm 20. Furthermore, controlling the operation of the multi-joint arm 20 includes correcting the tip position of the multi-joint arm 20 in response to changes in the posture of the multi-joint arm 20 caused by the swinging of the human body H, as described below. The tip position of the multi-joint arm 20 is the position of the hand 25 as viewed from the reference point P. Hereinafter, the tip position of the multi-joint arm 20 may be referred to as the position of the hand 25.

The swinging of the human body H refers to the swinging or tilting of the human body H. Correcting the tip position of the multi-joint arm 20 refers to bringing the tip position of the multi-joint arm 20, which has moved due to the swinging of the human body H, closer to the position it was in before the human body H swung.

In this embodiment, the tip position of the multi-joint arm 20 is corrected when the multi-joint arm 20 is not operating. When the multi-joint arm 20 is not operating, each of the multiple joints J is not rotating. When the multi-joint arm 20 is not operating, for example, when the hand 25 is gripping a workpiece so that the wearable robot 1 can perform a target task, and the human body H is not moving, the hand 25 and therefore the workpiece are stationary. In other words, when the hand 25 is stationary because the multi-joint arm 20 is not operating and the human body H swings, and the tip position of the multi-joint arm 20 is corrected, the multi-joint arm 20 operates so that the hand 25 remains stationary.

2, the control device 50 includes an input unit 51, an angle calculation unit 52, a sway determination unit 53, a correction angle calculation unit 54, an influence estimation unit 55, a correction execution determination unit 56, a trajectory generation unit 57, a target angle generation unit 58, a target angle addition unit 59, an angle error calculation unit 60, and an output unit 61. The control device 50 is configured by a processor that executes dedicated hardware or software. In other words, the control device 50 functions as the angle calculation unit 52, the sway determination unit 53, the correction angle calculation unit 54, the influence estimation unit 55, the correction execution determination unit 56, the trajectory generation unit 57, the target angle generation unit 58, the target angle addition unit 59, the angle error calculation unit 60, and the output unit 61 by executing a predetermined program that is pre-stored in a memory area (not shown) of the control device 50.

The input unit 51 acquires the detection results of the sensor 30 and the detection results of the angle detection unit E. The detection results of the angle detection unit E are stored in chronological order in the memory area of the control device 50.

The angle calculation unit 52 calculates the current angle of the multi-joint arm 20. The current angle of the multi-joint arm 20 is the angle at which the base 21 of the multi-joint arm 20 is tilted with respect to the vertical direction (Figure 3). Specifically, the angle calculation unit 52 obtains the angular velocity detected by the sensor 30 from the input unit 51 and integrates the obtained angular velocity to calculate the current angle of the multi-joint arm 20.

The swing determination unit 53 determines whether the human body H has swung when the multi-joint arm 20 is not moving. The swing determination unit 53 compares the detection result of the angle detection unit E acquired this time with the detection result of the angle detection unit E acquired last time and stored in the memory area. If both detection results have changed, the swing determination unit 53 determines that the multi-joint arm 20 is moving. If the swing determination unit 53 determines that the multi-joint arm 20 is moving, it transmits the current angle of the multi-joint arm 20 to the correction angle calculation unit 54 as zero.

On the other hand, the detection result of the angle detection unit E acquired this time is compared with the detection result of the angle detection unit E acquired last time and stored in the memory area, and if the detection result has not changed, the swing determination unit 53 determines that the multi-joint arm 20 is not moving. Note that the swing determination unit 53 may compare the detection result of the angle detection unit E acquired this time with multiple detection results of the angle detection unit E acquired up to last time and stored in the memory area to determine whether the multi-joint arm 20 is not moving.

When the swing determination unit 53 determines that the multi-joint arm 20 is not moving, it acquires the angular velocity transmitted from the sensor 30 via the input unit 51 and the current angle of the multi-joint arm 20 transmitted from the angle calculation unit 52. When the acquired angular velocity is smaller than a predetermined angular velocity, the swing determination unit 53 determines that the human body H is not swinging. When the swing determination unit 53 determines that the human body H is not swinging, it transmits the current angle of the multi-joint arm 20 as zero to the correction angle calculation unit 54.

On the other hand, if the acquired angular velocity is equal to or greater than the predetermined angular velocity, the swing determination unit 53 determines that the human body H has swung. If the swing determination unit 53 determines that the human body H has swung, it transmits the acquired current angle of the multi-joint arm 20 to the correction angle calculation unit 54.

The correction angle calculation unit 54 calculates a correction angle for correcting the joint angle of each joint J in order to correct the tip position of the multi-joint arm 20 in response to the swinging of the human body H.

When the correction angle calculation unit 54 obtains zero from the swing determination unit 53, it sets the correction angle to zero and transmits it to the influence estimation unit 55. When the correction angle is zero, the joint angle of each joint J is not corrected, and therefore the tip position of the multi-joint arm 20 is not corrected. The correction angle calculation unit 54 transmits the correction angle as zero when the swing determination unit 53 determines that the multi-joint arm 20 is moving, or when it determines that the human body H is not swinging when the multi-joint arm 20 is not moving. Therefore, when it is determined that the multi-joint arm 20 is moving, or when the human body H is not swinging when the multi-joint arm 20 is not moving, the tip position of the multi-joint arm 20 is not corrected.

Meanwhile, in response to acquiring the current angle of the multi-joint arm 20 that is greater than zero from the swing determination unit 53, the correction angle calculation unit 54 acquires the current joint angle of each joint J from the angle detection unit E via the input unit 51. Using the acquired current joint angle of each joint J, the correction angle calculation unit 54 calculates the position of the hand 25 in the absence of swing of the human body H based on kinematics.

Then, the correction angle calculation unit 54 calculates, as the correction angle of each joint J, the joint angle of each joint J required to position the hand 25 in the calculated position of the hand 25 when the human body H is not swinging, while the human body H is swinging. Specifically, the correction angle calculation unit 54 calculates the correction angle based on inverse kinematics using the calculated position of the hand 25 when the human body H is not swinging and the acquired current angle of the multi-joint arm 20.

Furthermore, the correction angle calculation unit 54 calculates the difference between the calculated correction angle of each joint J and the acquired current joint angle of each joint J as the correction angle of each joint J, and transmits the calculated correction angle of each joint J to the influence estimation unit 55.

The influence estimating unit 55 estimates the influence of the correction of the position of the hand 25 on the human body H. Specifically, the influence estimating unit 55 uses the correction angle of each joint J acquired from the correction angle calculating unit 54 to estimate the force applied to the human body H when the joint angle of each joint J and thus the tip position of the multi-joint arm 20 are corrected as the influence. The influence increases as the movement of the multi-joint arm 20 and thus the force applied to the human body H due to the correction increases. The relationship between the correction angle of each joint J and the influence is actually measured by an experiment or the like and derived in advance. The influence estimating unit 55 transmits the acquired correction angle and the estimated influence to the correction execution deciding unit 56. Note that when the influence estimating unit 55 acquires zero as the correction angle, it derives the influence to a value smaller than a predetermined value described later.

The correction execution decision unit 56 decides whether or not to correct the tip position of the multi-joint arm 20. If the acquired degree of influence is smaller than a predetermined value, the correction execution decision unit 56 decides to correct the tip position of the multi-joint arm 20, and transmits the acquired correction angle to the target angle addition unit 59. If the degree of influence is smaller than the predetermined value, the predetermined value is set so that the stability of the human body H is ensured even if the tip position of the multi-joint arm 20 is corrected.

On the other hand, if the degree of influence is equal to or greater than a predetermined value, when the tip position of the multi-joint arm 20 is corrected, a relatively large force acts on the human body H while it is swinging due to the correction, reducing the stability of the human body H. Therefore, if the acquired degree of influence is equal to or greater than a predetermined value, it is determined that the tip position of the multi-joint arm 20 will not be corrected, and the correction angle is transmitted to the target angle addition unit 59 as zero.

When the wearable robot 1 is powered on, the trajectory generation unit 57 acquires the target position and movement time of the hand 25 at a predetermined timing (e.g., every predetermined time). Based on the current position of the hand 25, as well as the acquired movement time and target position of the hand 25, the trajectory generation unit 57 generates time series data indicating the trajectory of the position of the hand 25 moving from the current position to the target position in the movement time. The current position of the hand 25 is the target position of the hand 25 acquired previously. The trajectory generation unit 57 stores the acquired target position of the hand 25 in chronological order in a memory area of the control device 50.

For example, when the wearable robot 1 is made to perform a target task, a target position of the hand 25 different from the target position of the hand 25 previously input is input in order to move the hand 25. When the target task is lifting a ceiling panel, for example, the user operates a switch (not shown) that sets the target position, and the control device 50 controls the camera 40 to acquire an image of the ceiling where the ceiling panel will be positioned. The control device 50 performs a predetermined image processing on the acquired image, and calculates the position to lift the ceiling panel, and therefore the target position of the hand 25. The calculated target position of the hand 25 is acquired by the trajectory generation unit 57. In addition, the movement time is calculated based on the distance between the calculated target position of the hand 25 and the current position of the hand 25, and is acquired by the trajectory generation unit 57.

On the other hand, if the control device 50 has not received an instruction to move the hand 25, the previously input target position and movement time of the hand 25 are repeatedly input.

The trajectory generation unit 57 transmits the positions of the hand 25 to the target angle generation unit 58 in sequence from the current position of the hand 25 to the target position of the hand 25 according to the generated time series data.

The target angle generation unit 58 uses the position of the hand 25 obtained from the trajectory generation unit 57 to generate a target angle for each joint J based on inverse kinematics.

The target angle addition unit 59 adds the acquired correction angle of each joint J to the generated target angle of each joint J.

The angle error calculation unit 60 acquires the current joint angle of each joint J from the angle detection unit E via the input unit 51, and calculates the difference between the acquired current joint angle and the target angle to which the correction angle has been added for each joint J.

The output unit 61 calculates a target angular velocity for each drive unit M using the difference for each joint J calculated by the angle error calculation unit 60. The output unit 61 is configured to include a PID compensator. That is, the output unit 61 calculates a target angular velocity so as to converge the difference to zero by appropriately adjusting three gains, proportional, differential, and integral, which are diagonal matrices of constants. The output unit 61 outputs the calculated angular velocity to each drive unit M as a control signal.

Next, with reference to the flowchart shown in FIG. 4, the program executed by the control device 50 described above and the operation of the wearable robot 1 when the program is executed will be described. In this embodiment, the program is repeatedly executed when the power supply of the wearable robot 1 is turned on.

In S10, the swing determination unit 53 determines whether the human body H swings when the multi-joint arm 20 is not moving. If the multi-joint arm is moving, or if the human body H is not swinging when the multi-joint arm 20 is not moving and the angular velocity measured by the sensor 30 is smaller than the predetermined angular velocity (NO in S10), the correction angle calculation unit 54 sets the correction angle to zero in S12 and causes the program to proceed to S16.

On the other hand, if the angular velocity measured by the sensor 30 is equal to or greater than the predetermined angular velocity due to the human body H swinging when the articulated arm 20 is not moving (YES in S10), the correction angle calculation unit 54 calculates the correction angle in S14.

Then, the influence estimation unit 55 estimates the influence in S16. Furthermore, the correction execution decision unit 56 determines whether the influence is equal to or greater than a predetermined value in S18. If the influence is less than the predetermined value because the sway of the human body H is relatively small (NO in S18), the correction execution decision unit 56 decides to execute correction in S20 and ends the program.

When correction is performed, the target angle adder 59 adds the correction angle to the target angle, and the output unit 61 outputs a control signal corresponding to the target angle to the drive unit M of each joint J. Therefore, even if the human body H swings when the multi-joint arm 20 is not moving, the rotation angle of the drive unit M and thus the operation of the multi-joint arm 20 are corrected, so that the hand 25 can reach a position where deviation from the target position is suppressed.

On the other hand, if the swaying of the human body H is relatively large and the degree of influence is equal to or greater than the predetermined value (YES in S18), the correction execution decision unit 56 decides not to execute correction in S22 and terminates the program.

When no correction is performed, the target angle adder 59 adds zero to the target angle, and the output unit 61 outputs a control signal corresponding to the target angle to the drive unit M of each joint J. Therefore, the rotation angle of the drive unit M and thus the operation of the multi-joint arm 20 are not corrected, ensuring the stability of the human body H.

Second Embodiment
Next, the wearable robot 1 according to a second embodiment of the present invention will be described with reference to Fig. 5 to Fig. 8, mainly focusing on the differences from the first embodiment. The control device 50 according to the second embodiment further includes a drive limiting unit 162 and a position determining unit 163 (Fig. 5).

When the swing determination unit 53 determines that the human body H has swung while the multi-joint arm 20 is not moving, the drive limiting unit 162 limits the movement of some of the joints J among the multiple joints J. Specifically, the drive limiting unit 162 limits the movement of some of the joints J when the degree of influence estimated by the influence estimation unit 55 is equal to or greater than a predetermined value.

The drive limiting unit 162 also determines the joint J whose movement is to be limited according to a predetermined priority order. The predetermined priority order is set so that the joint J located on the base end side of the multi-joint arm 20 is given priority over the joint J located on the tip end side of the multi-joint arm 20.

For example, when the movement of the first and second joints J1 and J2, which are the joints J arranged on the base end side of the multi-joint arm 20, is restricted, the movement of the multi-joint arm 20 is corrected by operating the third and fourth joints J3 and J4. When the third and fourth joints J3 and J4 operate, the third joint J3 to the tip side of the multi-joint arm 20 operates (Figure 6). Note that in Figure 6, the multi-joint arm 20 before operation is shown by a dashed line, and the multi-joint arm 20 after operation is shown by a solid line.

In contrast, when the movement of the third and fourth joints J3 and J4, which are the joints J located at the tip side of the multi-joint arm 20, is restricted, the movement of the multi-joint arm 20 is corrected by moving the first and second joints J1 and J2. When the first and second joints J1 and J2 move, the base end side of the multi-joint arm 20 moves from the third joint J3 (Figure 7). Note that in Figure 7, the multi-joint arm 20 before movement is shown by a dashed line, and the multi-joint arm 20 after movement is shown by a solid line.

6 and 7, when the multi-joint arm 20 is moved from a state in which the hand 25 is open upward as shown by the dashed line to a state in which the hand 25 is open upward to the upper right as shown by the solid line, the movement of the multi-joint arm 20, and thus the degree of influence, is greater when the third joint J3 of the multi-joint arm 20 moves from the base end side than when the third joint J3 of the multi-joint arm 20 moves from the tip side. Therefore, the predetermined priority order is set to give priority to restricting the joint J arranged on the base end side of the multi-joint arm 20 over the joint J arranged on the tip side of the multi-joint arm 20, so that the calculated degree of influence is smaller.

In addition, the correction angle calculation unit 54 in the second embodiment calculates a correction angle to correct the joint angle of the joint J that is the target of movement when the drive limiting unit 162 limits the movement of a part of the joint J.

The position determination unit 163 determines whether the tip position of the multi-joint arm 20 is within an acceptable range when the drive limiting unit 162 corrects the tip position of the multi-joint arm 20 while restricting the movement of some of the multiple joints J.

The position determination unit 163 calculates the distance between the tip position of the multi-joint arm 20 immediately before the human body H swings and the tip position of the multi-joint arm 20 corrected due to the swing of the human body H. The tip position of the multi-joint arm 20 immediately before the human body H swings is a position calculated using the current joint angles of each joint J when the human body H is not swinging, i.e., when the current angle of the multi-joint arm 20 is set to zero.

When the human body H swings, the tip of the multi-joint arm 20 moves a distance according to the swing angle of the human body H from the position immediately before swinging. Here, when correction is applied, the tip of the multi-joint arm 20 approaches the position it was in immediately before the human body H swings. In other words, the tip position of the multi-joint arm 20 corrected due to the swing of the human body H is the position to which the tip of the multi-joint arm 20 moves by correcting the joint angles of each joint J using the correction angle, starting from the position where the tip of the multi-joint arm 20 will be located as a result of the swing of the human body H. The position where the tip of the multi-joint arm 20 will be located as a result of the swing of the human body H is calculated using the current angle of the multi-joint arm 20.

If the distance between the tip position of the multi-joint arm 20 immediately before the human body H swings and the tip position of the multi-joint arm 20 corrected due to the swing of the human body H is less than a predetermined distance, the position determination unit 163 determines that the tip position of the multi-joint arm 20 is within the allowable range.

On the other hand, if the distance between the tip position of the multi-joint arm 20 immediately before the human body H swings and the tip position of the multi-joint arm 20 corrected due to the swing of the human body H is greater than the predetermined distance, the position determination unit 163 determines that the tip position of the multi-joint arm 20 is not within the allowable range.

Next, with reference to the flowchart shown in FIG. 8, the program executed by the control device 50 of the second embodiment and the operation of the wearable robot 1 when the program is executed will be described. In the second embodiment, the program is executed repeatedly when the wearable robot 1 is performing a target task.

When the wearable robot 1 is performing a target task, as described above, the output unit 61 outputs the target angular velocity as a control signal to the drive unit M of each joint J, and each joint J and thus the multi-joint arm 20 operate, moving the hand 25 toward the target position.

Note that steps S10 to S20 in the flowchart in FIG. 8 are the same as steps S10 to S20 in the flowchart in FIG. 4. Therefore, the explanation will begin with step S30 in the flowchart in FIG. 8.

If the degree of influence is equal to or greater than a predetermined value due to a relatively large swing of the human body H (YES in S18), the drive limiting unit 162 limits the movement of some of the joints J in S30. The drive limiting unit 162 limits the movement of one of the multiple joints J in accordance with a predetermined priority order. Specifically, the drive limiting unit 162 limits the movement of the first joint J1 located at the most proximal end of the multi-joint arm 20. The drive unit M that drives the joint J whose movement is limited is not subject to control.

Next, in S32, it is determined whether the number of drive units M to be controlled is one or more. When the movement of the first joint J1 is restricted, the drive units M in the second to fourth joint units J2 to J4 become the control units. Since one drive unit M is disposed at each of the second and third joint units J2 and J3, and two drive units M are disposed at the fourth joint unit J4, the number of drive units M to be controlled is four. In this case (YES in S32), the position determination unit 163 determines in S34 whether the corrected tip position of the multi-joint arm 20 is within the allowable range with the movement of some of the joint units J restricted.

When correcting the tip position of the articulated arm 20, if the movement of some of the joints J is restricted, the accuracy of the correction is reduced compared to when the movement of some of the joints J is not restricted. If the position of the hand 25 is not within the allowable range due to a relatively large decrease in the accuracy of the correction (NO in S34), the correction execution decision unit 56 decides not to execute the correction in S36, and the program ends.

On the other hand, if the decrease in the accuracy of the correction is relatively small and the position of the hand 25 is within the allowable range (YES in S34), the influence estimator 55 re-estimates the influence in S38 with the movement of the first joint J1 restricted. Since the movement of the first joint J1 is restricted, the movement of the multi-joint arm 20 is smaller than when the movement of the joint J is not restricted, and therefore the influence re-estimated in S38 is smaller than the influence estimated in S16.

Then, in S40, the correction execution decision unit 56 determines whether the re-estimated degree of influence is equal to or greater than a predetermined value. Since the reduction in the degree of influence is relatively large due to the restriction on the movement of the first joint J1, if the re-estimated degree of influence is smaller than the predetermined value (NO in S40), the correction execution decision unit 56 decides to execute correction in S42, and the program ends.

On the other hand, since the reduction in the degree of influence due to the restriction on the movement of the first joint J1 is relatively small, if the re-estimated degree of influence is equal to or greater than the predetermined value (YES in S40), the program returns to S30.

In S30, the drive limiting unit 162 further limits the movement of one of the joints J in accordance with a predetermined priority order. Specifically, the drive limiting unit 162 limits the movement of the second joint J2, which is located at the most proximal end of the multi-joint arm 20, among the joints J whose movement is not limited. As a result, the movements of the first and second joints J1 and J2 are limited, and the drive units M at the third and fourth joints J3 and J4 become the control targets.

Then, the above-mentioned steps S32 to S34 are executed with the movement of the first and second joints J1 and J2 restricted. If the tip position of the articulated arm 20 is within the allowable range (YES in S34), the influence degree estimation unit 55 re-estimates the influence degree with the movement of the first and second joints J1 and J2 restricted in S38.

The correction execution decision unit 56 further determines in S40 whether the re-estimated degree of influence in a state in which the movements of the first and second joints J1 and J2 are restricted is equal to or greater than a predetermined value. If the re-estimated degree of influence is less than the predetermined value (NO in S40), the correction execution decision unit 56 determines to execute correction in S42 and terminates the program.

On the other hand, since the decrease in the degree of influence due to the restriction on the movement of the first and second joints J1 and J2 is relatively small, if the re-estimated degree of influence is equal to or greater than the predetermined value (YES in S40), the program returns to S30.

In this way, the movement of each of the multiple joints J is restricted one by one in accordance with a predetermined priority order (S30), and if the tip position of the multi-joint arm 20 is within the allowable range (YES in S34) and the re-estimated degree of influence is smaller than a predetermined value (NO in S40), a decision is made to execute correction.

In addition, if the number of drive units M to be controlled becomes zero due to the restriction of the movements of all joint units J in S30 (NO in S32), the correction execution decision unit 56 decides not to execute correction in S44, and the program ends.

In this way, if the estimated degree of influence when all joints J are in motion is equal to or greater than a predetermined value, the estimated degree of influence is suppressed because the degree of influence when correcting the position of the hand 25 is estimated while restricting the motion of some of the joints J. Therefore, correction with suppressed degree of influence can be performed.

In addition, correction is performed when the position of the hand 25 corrected while restricting the movement of some of the joints J is within an acceptable range. This prevents a decrease in the accuracy of the correction.

<Modification>
The present invention is not limited to the embodiments described above. As long as they do not deviate from the gist of the present invention, various modifications of the present embodiments and combinations of components in different embodiments are also included within the scope of the present invention.

For example, the degree of influence is the force applied to the human body H when the tip position of the multi-joint arm 20 is corrected, but instead, it may be the moment applied to the human body H when the tip position of the multi-joint arm 20 is corrected. Furthermore, the degree of influence may be derived based on the force and moment applied to the human body H when the tip position of the multi-joint arm 20 is corrected.

The predetermined value may be different depending on the direction of influence on the human body H when the tip position of the multi-joint arm 20 is corrected. For example, the predetermined value may be set so that the force applied to the human body H when the tip position of the multi-joint arm 20 is corrected is smaller when the force acts in the left-right direction than when the force acts in the front-back direction.

The predetermined value may be different depending on the magnitude of the sway of the human body H, i.e., the angle calculated by the angle calculation unit 52. Specifically, the predetermined value may be set to be smaller as the angle calculated by the angle calculation unit 52 becomes larger.

The correction of the tip position of the multi-joint arm 20 may also be performed when the multi-joint arm 20 is operating. In this way, even when the multi-joint arm 20 is operating, if the estimated degree of influence is smaller than a predetermined value, the correction of the tip position of the multi-joint arm 20 is performed, so that a decrease in the stability of the human body can be suppressed.

In addition, the drive limiting unit 162 in the second embodiment limits the movement of some of the multiple joints J in S30 when the degree of influence when all joints J move becomes equal to or greater than a predetermined value, but instead, the degree of influence may be estimated by limiting the movement of some of the multiple joints J from the beginning.

In addition, in the second embodiment, the control device 50 does not need to include a position determination unit 163. In this case, even if the corrected position of the hand 25 is not within the allowable range, if the degree of influence is smaller than a predetermined value, a decision is made to execute the correction.

Additionally, the drive limiting unit 162 limits the movement of each joint J one at a time, but is not limited to this and may limit the movement of multiple joints J at once.

The predetermined priority order may also be set so as to prioritize restriction of the joint part J located at the tip end of the multi-joint arm 20 over the joint part J located at the base end of the multi-joint arm 20, in the opposite order to that described above.

In addition, the drive limiting unit 162 limits the movement of some of the joints J according to a predetermined priority order, but instead, it may randomly select the joints J whose movement is to be limited without following a predetermined priority order.

Additionally, the drive unit M is a motor, but it may be a pneumatic actuator, a solenoid, or a linear motor, or may be a combination of these.

The control device 50 may be separate from the wearable robot 1. In this case, the sensor 30, the camera 40, and the drive unit M and angle detection unit E of each joint J are connected to the control device 50 so as to be able to communicate with each other via wire or wirelessly. In other words, the multi-joint arm 20 is remotely controlled by the control device 50. In this case, the control device 50 may be, for example, a smartphone. In this case, the input unit 51 and the output unit 61 of the control device 50 constitute a "signal transmission/reception unit."

This invention can be widely used in wearable robots.

Reference Signs List 1 Wearable robot 10 Wearing unit 20 Articulated arm 30 Sensor 50 Control device H Human body J Joint

Claims (11)

A multi-joint arm attached to the human body;
A sensor for detecting a posture of the articulated arm;
A control device that corrects a tip position of the articulated arm,
The control device includes:
determining whether the human body has swayed based on the detection result of the sensor;
When it is determined that the human body has swung, estimating the degree of influence that a correction of the tip position of the articulated arm has on the human body;
If the estimated degree of influence is smaller than a predetermined value, a correction is made to the tip position of the articulated arm.
Wearable robot. The control device includes:
When it is determined that the human body has swung, estimating the degree of influence that a correction of a tip position of the multi-joint arm has on the human body in a state in which the movement of some of the multiple joints of the multi-joint arm is restricted.
The wearable robot according to claim 1 . The control device includes:
If the estimated degree of influence is equal to or greater than the predetermined value, re-estimating the degree of influence on the human body caused by the correction of the tip position of the multi-joint arm in a state in which the joint that limits the movement is changed;
If the re-estimated influence degree is smaller than the predetermined value, a correction of the tip position of the articulated arm is executed.
The wearable robot according to claim 2. The control device includes:
determining, in a predetermined order of priority, joints whose movements are to be restricted when estimating the degree of influence on the human body and joints whose movements are to be restricted when re-estimating the degree of influence on the human body;
The wearable robot according to claim 3. the predetermined priority order is determined so as to give priority to restricting a joint portion arranged on a base end side of the multi-joint arm over a joint portion arranged on a tip end side of the multi-joint arm,
The wearable robot according to claim 4. The control device includes:
calculating a tip position of the multi-joint arm when the tip position of the multi-joint arm is corrected in a state in which the movement of some of the plurality of joints is restricted;
when the calculated tip position of the multi-joint arm is within an allowable range and the degree of influence is smaller than the predetermined value, correcting the tip position of the multi-joint arm.
The wearable robot according to any one of claims 2 to 5. The sensor is a gyro sensor.
The wearable robot according to any one of claims 1 to 6. The sensor is an acceleration sensor.
The wearable robot according to any one of claims 1 to 6. A program for correcting a tip position of a multi-joint arm attached to a human body,
On the computer,
Detecting a posture of the articulated arm;
determining whether the human body has swung based on the detected posture of the articulated arm;
estimating an effect of a correction of a tip position of the articulated arm on the human body when it is determined that the human body has swung;
and if the estimated degree of influence is smaller than a predetermined value, executing a correction of the tip position of the articulated arm.
program. A control method for correcting a tip position of a multi-joint arm attached to a human body, comprising the steps of:
Detecting a posture of the articulated arm;
determining whether the human body has swung based on the detected posture of the articulated arm;
estimating an effect of a correction of a tip position of the articulated arm on the human body when it is determined that the human body has swung;
and when the estimated degree of influence is smaller than a predetermined value, correcting a tip position of the articulated arm.
Control methods. a signal transmitting/receiving unit that receives a detection result of a sensor that detects the posture of a wearable robot worn on a human body and transmits a control signal to cause the wearable robot to correct a tip position of the wearable robot;
a computer for generating the control signal;
The computer includes:
determining whether the human body has swayed based on the detection result of the sensor;
When it is determined that the human body has swayed, estimating the degree of influence that a correction of the tip position of the wearable robot has on the human body;
generating the control signal when the estimated influence degree is smaller than a predetermined value;
Control device.

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