JP7435212B2 - assist device - Google Patents

Description

The presently disclosed invention relates to an assist device.

Various assist devices have been proposed that are attached to the body of a user (person) and assist the user's work. According to the assist device, the user can perform the task with little force (small burden) even when lifting a heavy object, for example. Such an assist device is disclosed in Patent Document 1, for example.

Japanese Patent Application Publication No. 2018-199205

The assist device disclosed in Patent Document 1 has a frame made of metal or the like that is worn by a user. The output of the actuator mounted on the frame is transmitted to the user's upper and lower body through the link mechanism. This assists, for example, in lifting heavy objects.

Actions that require assistance by the user include, in addition to actions that impose a large load such as lifting heavy objects, there are also actions that provide assistance (assistance) to people, such as sick or elderly people, in their daily living activities. When a user performs heavy-load work, a high-output assist device as disclosed in Patent Document 1 is effective.

However, when a user provides assistance to a person, such as a sick person or an elderly person, a high-output assist device may have excessive performance. Further, high-output assist devices often use rigid members such as link mechanisms and metal frames, and have a heavy structure in order to obtain high output. Therefore, the weight of the assist device increases, and the user's movement is restricted by the rigid member.

Therefore, the inventor of the present invention has already proposed an assist device that is lightweight and comfortable to wear (for example, Japanese Patent Application No. 2019-043462). The assist device includes a first attachment device that is attached to the user's shoulder, a second attachment device that is attached to the left and right legs of the user, and a first attachment device that is attached to the user's left and right legs. The device includes a belt body provided along the back side of the device, and an actuator. The actuator is provided on the first mounting tool and enables winding and feeding of a portion of the belt body.

When the actuator winds up a portion of the belt body, tension is applied to the belt body. This tension acts as an assist force on the user. This reduces the burden on the user when, for example, providing assistance to someone as described above.

The assist device including the belt body as described above is used by users of various physiques. For this reason, when the length of the belt body is set to match, for example, a standard height, when a user who is taller than the standard height wears the assist device, the belt body is pulled more than necessary. In this case, the assist device may not be able to generate an appropriate assist force, or it may be difficult to walk.

Therefore, an object of the present disclosure is to provide an assist device that is lightweight, comfortable to wear, and capable of generating an assist force according to the user's physique.

The assist device of the present disclosure includes a first wearing tool attached to at least one of a shoulder and a chest of a user, a second wearing tool attached to each of the left and right legs or waist of the user, and the second wearing tool attached to the user's left and right legs or waist. A belt body provided along the back side of the user across the first wearing tool and the second wearing tool; and a belt body provided on the first wearing tool or the second wearing tool and winding a part of the belt body. An actuator that enables feeding, and a control unit that controls the operation of the actuator. When the operation of the actuator is started, the belt body is wound up using a first winding force, and when the winding of the belt body is completed, the winding force by the actuator is increased from the first winding force. Also change to a smaller second winding force.

According to the assist device having the above configuration, the belt body is provided along the back side of the user across the first wearing tool and the second wearing tool. When the belt body is wound up by the actuator, tension is applied to the belt body. The tension creates an assisting force that assists the user's work, reducing the burden on the user's body. The belt body is lightweight, can follow the user's body even when the user changes posture, and follows the user's movements. Therefore, an assist device that is comfortable to wear can be obtained.

Furthermore, according to the assist device having the above configuration, even if the belt body is loosened in advance when the user wears the assist device, when the actuator starts operating, the belt body will loosen due to the user's physique ( For example, the length will be automatically adjusted according to your height. When winding of the belt body is completed, the winding force is changed to a second winding force smaller than the first winding force. Since the second winding force is small, the user's movements are not hindered by the belt body after the assist device is attached. Since the length of the belt body is adjusted to suit the user's physique, it is possible to generate an assisting force according to the user's physique.

Note that if tension is applied to the belt body, the second winding force may be zero, but is preferably greater than zero. That is, preferably, when winding of the belt body is completed, the control section changes the winding force by the actuator to a second winding force that is smaller than the first winding force and larger than zero.
According to this configuration, even if the user makes a small movement, for example, by changing his posture after wearing the assist device, the belt body does not loosen easily.

Preferably, the actuator includes a pulley capable of winding up the belt body, and a motor for causing the pulley to wind up the belt body, and the control unit is configured to control the pulley or the Completion of winding of the belt body is detected based on parameters related to rotation of the motor.
According to this configuration, it is possible to detect completion of winding of the belt body with a simple configuration. When winding of the belt body is completed, the winding force by the actuator is changed from the first winding force to the second winding force.

Preferably, the actuator includes a pulley capable of winding up the belt body, and a motor for causing the pulley to wind up the belt body, and the control unit controls the motor. By reducing the supply current, the winding force by the actuator is changed.
According to this configuration, with a simple configuration, it is possible to change the winding force of the belt body by the actuator to the second winding force that is smaller than the first winding force.

The amount of winding of the belt body by the first winding force varies depending on the user's height. Therefore, preferably, the actuator includes a pulley capable of winding up the belt body, and a motor for causing the pulley to perform a winding operation of the belt body, and the control unit is configured to control the actuator for winding the belt body. When the take-up force is changed to the second take-up force, the phase of the motor at the time of the change is set as the initial value of the phase of the motor.
According to this configuration, the phase of the motor is initially set according to the user's physique. Using this initial setting as a reference, it becomes possible to control the rotation of the motor and generate an appropriate assist force.

Preferably, the actuator includes a motor, a speed reducer section that is configured of a plurality of gears and that decelerates and outputs the rotation of the motor, and a speed reducer section that rotates due to the output of the speed reducer section so that the belt body a pulley capable of winding up the
When the belt body is sent out from the pulley, the motor applies a torque to the pulley through the reduction gear unit in a direction to wind up the belt body, and the pulley rotates in a direction to send out the belt body.
According to this configuration, even when the belt body is sent out from the pulley, the motor applies a torque in a direction to wind the belt body to the pulley through the reduction gear unit. That is, tension acts on the belt body both when the belt body is wound up and when the belt body is fed out. Whether the belt body is being wound up or fed out, the speed reducer section is designed to prevent response delays in assist force generation due to backlash between gears and impact generation due to backlash. It becomes possible to prevent this.

In the assist device, when the actuator starts operating with the first wearing tool and the second wearing tool being worn by the user, the belt body is wound up by the first winding force. If the first winding force is large throughout, there is a possibility that the impact force transmitted from the belt body to the user will become large when winding is completed.
Therefore, preferably, when the operation of the actuator is started, the control unit makes the first winding force smaller in a time period after the start of winding than at the start. Perform control to change. According to this configuration, the first winding force becomes weak toward the completion of winding the belt body. Therefore, when winding is completed, it is possible to prevent impact force from being applied to the user from the belt body.

Moreover, when the operation of the actuator is started, the control unit changes the winding speed of the belt body in a time period after the start of winding so as to be lower than at the start. It may be configured to perform control. In this case, the winding speed of the belt body decreases toward the completion of winding the belt body. Therefore, when winding is completed, it is possible to prevent impact force from being applied to the user from the belt body.

According to the assist device of the present disclosure, it is lightweight and comfortable to wear, and it is possible to generate an assist force according to the user's physique.

FIG. 2 is a rear view showing an example of an assist device. FIG. 3 is a rear view of the assist device attached to the user's body. FIG. 3 is a side view of the assist device attached to the user's body. FIG. 2 is an explanatory diagram showing a state in which a user wearing an assist device is in a forward leaning posture. It is an explanatory view of a control box and a belt body. FIG. 2 is a block diagram showing a control configuration included in the assist device. FIG. 3 is a flow diagram showing initial setting processing. It is an explanatory diagram when a user wearing an assist device changes his posture. It is a side view which shows the assist device of another form. 7 is a graph showing temporal changes in the current value supplied to the motor due to the function of the adjustment section. 7 is a graph showing temporal changes in the current value supplied to the motor due to the function of the adjustment section. 7 is a graph showing changes over time in the rotational speed of the motor due to the function of the adjustment section. 7 is a graph showing changes over time in the rotational speed of the motor due to the function of the adjustment section.

[Overall configuration of assist device 10]
FIG. 1 is a rear view showing an example of an assist device. FIG. 2 is a rear view of the assist device attached to the user's body. FIG. 3 is a side view of the assist device attached to the user's body. FIG. 4 is an explanatory diagram showing a state in which the user wearing the assist device is in a forward leaning posture (forward bending posture). The assisting device 10 shown in FIG. and two second mounting tools 12 that are mounted on the leg portions BL of. The first mounting tool 11 only needs to be mounted on at least one of the user's shoulder BS and chest BB, and may have a form other than the one shown. In the present disclosure, the second mounting tool 12 is mounted on the knee BN of the leg BL. The second mounting tool 12 may also have a form other than that illustrated.

In the assist device 10 of the present disclosure, left and right are left and right for a user who is wearing the assist device 10 in an upright posture, front and rear are front and rear for the user, and up and down are upper and lower for the user. be. The upper side is the user's head side, and the lower side is the user's foot side.

The assist device 10 includes a belt body 13, an actuator 14, a control section 15, a battery 37, and a sensor 38 in addition to a first mounting tool 11 and second mounting tools 12 on either side.

The first mounting tool 11 is mounted on the user's shoulder BS. One of the second attachment tools 12 is attached to the user's left knee BN. The other second attachment tool 12 is attached to the user's right knee BN. The second mounting tool 12 on the left side and the second mounting tool 12 on the right side are symmetrical, but have the same configuration. The first mounting tool 11 and the two second mounting tools 12 are mounted at two locations separated from each other across the waist BW, which is a joint of the user, that is, the shoulder BS and the leg BL.

The first mounting tool 11 is made of flexible fabric or the like. The first mounting tool 11 includes a back main body part 21 that is mounted on the user's back, and a shoulder belt 22 and an armpit belt 23 that are connected to the back main body part 21. The shoulder belt 22 and the armpit belt 23 allow the back body portion 21 to be carried on the user's back. The armpit belt 23 connects the back main body part 21 and the shoulder belt 22, and its length is adjustable. By adjusting the length of the armpit belt 23, the back body portion 21 comes into close contact with the user's back. The first mounting tool 11 is mounted on the shoulder BS so as to be immovable in the front and back, left and right, and up and down directions. The first mounting tool 11 may include, for example, a hard member as a portion that hangs over the shoulder portion BS.

The second mounting tool 12 is made of flexible fabric or the like. The second mounting tool 12 includes a knee body portion 24 that is attached to the rear side of the user's knee portion BN, and a knee belt 25 that extends from the knee body portion 24. The knee belt 25 goes around the knee part BN at the upper and lower positions of the knee part BN, and its distal end side is fixed to the knee body part 24. The length of the lap belt 25 wrapped around the knee portion BN can be adjusted using a belt and a buckle, or a locking member such as a hook and loop fastener. With this adjustment, the knee body portion 24 is brought into close contact with the rear surface side of the knee portion BN. The second mounting tool 12 is attached to the knee part BN so as to be immovable in the front and back, left and right, and up and down directions.

The belt body 13 is provided along the back side of the user so as to connect the first wearing tool 11 and the second wearing tool 12. The belt body 13 includes a first belt 16 provided on the upper body side, a second belt 17 provided on the lower body side, and a connecting member 18 connecting the first belt 16 and the second belt 17. have Each of the first belt 16 and the second belt 17 is long and flexible. The connecting member 18 is made of metal and is constituted by a rectangular annular body called a "flat ring".

Each of the first belt 16 and the second belt 17 is a band-shaped member made of cloth or leather, and can be bent to conform to the shape of the body. Note that each of the first belt 16 and the second belt 17 may be a string-like belt (a wire-like member). Each of the first belt 16 and the second belt 17 of the present disclosure is a non-stretchable member, that is, has a characteristic that it is difficult to stretch or not stretch in the longitudinal direction.

The assist device 10 of the present disclosure includes a control box 30. The control box 30 is provided on the back body portion 21 of the first mounting tool 11. FIG. 5 is an explanatory diagram of the control box 30 and the belt body 13. The control box 30 has a plate-shaped base 31 and a cover 32 that covers the base 31. In order to explain the internal structure of the control box 30, the cover 32 is shown by a virtual line (two-dot chain line) in FIG. The base 31 may be the back body portion 21 of the first mounting tool 11.

In the space formed between the base 31 and the cover 32, the actuator 14, the control section 15, the battery 37, the sensor 38, etc. are provided. An opening (notch) 32a is formed in the cover 32, and the first belt 16 passes through this opening 32a.

The actuator 14 is provided within the control box 30. That is, the actuator 14 is provided on the first mounting tool 11. The actuator 14 makes it possible to wind up and feed out a portion of the belt body 13. For this purpose, the actuator 14 includes a motor 33, a speed reducer section 34, and a drive pulley 35. Motor 33 is a brushless DC motor. The motor 33 can rotate at a predetermined torque and a predetermined rotation speed based on a drive signal output from the control unit 15. The motor 33 can rotate in forward and reverse directions based on a drive signal output from the control section 15.

Parameters related to rotation, such as the rotation angle, rotation speed, or number of rotations of the motor 33, are detected by a rotation detector 36 attached to the motor 33. The rotation detector 36 of the present disclosure is a rotary encoder, but may also be a Hall sensor or a resolver. The detection result of the rotation detector 36 is input to the control section 15. The control unit 15 controls the operation of the motor 33 based on the detection result, so that the assist device 10 can generate an appropriate assist force.

The speed reducer section 34 is composed of a plurality of gears 34g, and reduces the rotation speed of the motor 33 to rotate the output shaft 34a of the speed reducer section 34. A drive pulley 35 is connected to the output shaft 34a and rotates together. One end 16a side of the first belt 16 is attached to the drive pulley 35. When the drive pulley 35 rotates in one direction due to the forward rotation of the motor 33, the first belt 16 is wound around the drive pulley 35. When the drive pulley 35 rotates in the other direction due to the reverse rotation of the motor 33, the first belt 16 is sent out from the drive pulley 35.

In this way, the actuator 14 includes the drive pulley 35 capable of winding up the belt body 13 and the motor 33 for causing the drive pulley 35 to wind up the belt body 13 . The first belt 16 is wound or fed out by the actuator 14.

The control section 15 is constituted by a control unit including a microcomputer. As will be described later, the control unit 15 controls the operation of the actuator 14 (motor 33). As the sensor 38, an acceleration sensor is provided. A signal from the sensor 38 is input to the control section 15. The control unit 15 can estimate the user's posture based on the signal from the sensor 38. The battery 37 supplies power to the control unit 15, motor 33, rotation detector 36, and sensor 38. The sensor 38 may be provided outside the control box 30.

[About the belt body 13]
As described above, the belt body 13 includes the first belt 16, the second belt 17, and the connecting member 18. One end 16a side of the first belt 16 is wound around and fixed to a drive pulley 35. The other end 16b side of the first belt 16 is fixed to the connecting member 18. When the first belt 16 is wound around the drive pulley 35, the connecting member 18 is pulled up. When the connecting member 18 is forcibly pulled down, the first belt 16 is unwound (pulled out) from the drive pulley 35. There is a correlation between the amount of winding or unwinding (pulling amount) of the first belt 16 on the drive pulley 35 and the amount of rotation of the output shaft of the motor 33 . A rotation detector 36 detects parameters related to the rotation of the motor 33 as the belt body 13 is wound up or unwound.

As described above, the connecting member 18 is constituted by a rectangular annular body. A shaft portion 27a on one side (upper side) of the annular body is a first attachment portion 27, and an end portion 16b of the first belt 16 is attached to the first attachment portion 27. In the present disclosure, the first belt 16 is not removable from the first attachment portion 27, but may be removable with a buckle or the like.

The other side (lower side) of the rectangular annular body constituting the connecting member 18 is a second attachment portion 28 to which the second belt 17 is attached. In this way, the connecting member 18 has a first attachment part 27 for attaching the first belt 16 and a second attachment part 28 for attaching the second belt 17.

The second attachment portion 28 supports the second belt 17 in a state where it is folded back midway (midway portion 17c). The second attachment portion 28 of the present disclosure includes a shaft portion 28a that is integral with the first attachment portion 27, and a rotary pulley 29 rotatably supported by the shaft portion 28a. The second belt 17 is hung on the rotating pulley 29 in a state where it is folded back in the middle. With this configuration, the second belt 17 is not fixed to the second attachment part 28, but is in a folded state, but can be moved in both longitudinal directions (arrow X direction in FIG. 5). A freely supporting configuration is obtained.

In FIG. 2, the second belt 17 is attached to the second mounting tool 12. Specifically, the second belt 17 is composed of a single belt-shaped member. One end 17a side of the second belt 17 is attached to the second mounting tool 12 on the left. The other end 17d side of the second belt 17 is attached to the right second mounting tool 12. As described above, the middle portion 17c of the second belt 17 is hung on the connecting member 18.

According to the configuration of the second belt 17 as described above, the second belt 17 includes the left second belt portion 19 from the connecting member 18 to the left second mounting tool 12, and the left second belt portion 19 from the connecting member 18 to the right second mounting tool 12. It has a second right belt section 20 that extends up to the mounting tool 12. As described above (see FIG. 5), the second belt 17 is hung on the second attachment part 28 (rotary pulley 29) and is not fixed, so the length of the second left belt part 19 and the second right belt part 17 are different. The length of the belt portion 20 can be freely changed. However, the total length of the second left belt section 19 and the length of the second right belt section 20 is constant. With this configuration, the user's walking, for example, is not restricted by the second belt 17, and the user can walk comfortably.

The second belt 17 further includes a connecting member 39 that connects the left second belt section 19 and the right second belt section 20. The connecting member 39 is connected to the left second belt at an intermediate position between the folded part (midway part 17c) of the second belt 17 and the fixing part (one end part 17a, the other end part 17d) of the two second attachment tools 12. The belt portion 19 and the second right belt portion 20 are connected. The folded portion is a portion of the connecting member 18 where the second belt 17 is folded back. The fixing portion is a portion where the second belt 17 is fixed to each of the two second mounting tools 12.

For example, when the user changes his or her posture from an upright posture to a bent forward posture as shown in FIG. This makes it possible to prevent the interval from widening. In other words, it is possible to prevent the second left belt section 19 and the second right belt section 20 from coming out of alignment with the back side of the user's leg BL.

[About the sensor 38 and the control unit 15]
In FIG. 5, as described above, the sensor 38 is constituted by an acceleration sensor. The control unit 15 is capable of performing various calculation processes. By arithmetic processing of the signal from the sensor 38 by the control unit 15, the motion and posture of the user can be detected. The sensor 38 has a configuration that outputs a signal according to the user's posture, and functions as a posture detector for detecting the user's posture. For example, it is possible to detect whether the user's upper body is leaning forward or standing upright, or to detect whether the user is in a crouched position.

Further, there is a correlation between the winding amount and the feeding amount of the belt body 13 by the drive pulley 35 by the motor 33 and the posture of the user. Therefore, the control unit 15 can estimate the user's posture based on the rotation angle of the motor 33 detected by the rotation detector 36. The rotation detector 36 functions as a posture detector for detecting the posture of the user.

The control unit 15 processes signals from one or both of the sensor 38 and the rotation detector 36, and outputs a drive signal to the actuator 14 (motor 33) according to the processing result, that is, the posture of the user. . Based on the drive signal, the actuator 14 (motor 33) operates to wind up and feed out the belt body 13, as well as to temporarily stop the belt body 13.

When the assist device 10 is worn by the user, the motor 33 is constantly operated in the direction of winding the belt body 13 under the control of the control unit 15 with a force weaker than when generating an assist force. (Torque is generated as a second winding force to be described later), and a weak tension is generated in the belt body 13. This prevents the belt body 13 from loosening.

When the user changes his posture, for example from an upright posture to a forward leaning posture, tension is generated in the belt body 13 due to the change in posture. Therefore, in this case, when a posture change is started to take a forward leaning posture, the motor 33 is forcibly rotated by the tension of the belt body 13 (the motor 33 idles), not by the power of the actuator 14. The belt body 13 is unwound. Alternatively, when the posture changes to a forward-leaning posture, the actuator 14 operates, that is, rotates the motor 33 to send out the belt body 13.

On the other hand, when the user changes from a forward leaning posture to an upright posture, the belt body 13 tends to loosen due to the change in posture. Therefore, in this case, when the posture change starts to take an upright posture, the actuator 14 operates, that is, rotates the motor 33 to maintain the tension acting on the belt body 13. wind up.

In this way, the belt body 13 is wound up or fed out by changing the user's posture. During this winding or feeding, the motor 33 is actively or passively rotated by a predetermined rotation angle. The rotation angle at this time is detected by the rotation detector 36. In this way, the rotation detector 36 detects the amount of operation of the actuator 14 (motor 33) when the belt body 13 is wound up or fed out due to a change in the user's posture.
Then, the control unit 15 acquires the amount of operation of the actuator 14 (rotation angle of the motor 33) when the belt body 13 is wound up or fed out due to a change in the user's posture, and based on the amount of operation, the controller 15 The operation of the actuator 14 is controlled to apply assist force.

FIG. 6 is a block diagram showing a control configuration included in the assist device 10. The control section 15 is constituted by a control unit including a microcomputer, and includes an arithmetic processing unit (CPU) 15a and a storage device (storage section) 15b such as a memory. The arithmetic processing unit 15a executes various arithmetic processes based on various programs and various parameters stored in the storage device 15b. The control unit 15 of the present disclosure includes a startup unit 42a, an adjustment unit 42b, and a setting unit 42c as functional units realized by calculation processing by the calculation processing unit 15a. The control unit 15 further includes a drive circuit (motor driver) 15c that controls the operation of the motor 33. The motor 33 executes a predetermined operation by the cooperation of each of the above-mentioned functional units and the drive circuit 15c.

When the activation switch 41 is turned on with the assist device 10 being worn by the user, the control unit 15 performs initial setting processing. Note that the activation switch 41 is provided on the control box 30 (see FIG. 1), the shoulder belt 22, etc., and is operated by the user. The starting switch 41 is a switch for starting and stopping the assist device 10.

The activation unit 42a activates the actuator 14 and starts winding the belt body 13. That is, the starting unit 42a causes the drive pulley 35 to take up the belt body 13 by rotating the motor 33.

The adjustment section 42b adjusts the winding force of the belt body 13. The winding force of the belt body 13 is generated based on the rotational torque of the drive pulley 35, and the rotational torque is generated based on the output torque of the motor 33. Therefore, in order to adjust the winding force of the belt body 13, the adjustment section 42b controls the drive circuit 15c to change the output torque of the motor 33. The adjustment unit 42b can reduce the output torque of the motor 33 by reducing the current supplied to the motor 33. That is, by reducing the current supplied to the motor 33, the winding force by the actuator 14 is changed to a second winding force that is smaller than the first winding force, as will be explained later. Furthermore, the adjustment section 42b can increase the output torque of the motor 33 by increasing the current supplied to the motor 33.

When the assist device 10 is worn by the user, the starting section 42a starts winding up the belt body 13. As will be explained later, in order to provide assisting force to the user performing the work, the belt body 13 must be in a state where it is not slack, that is, a state where the belt body 13 is wound around the drive pulley 35 and the winding is completed. (This state is the "initial state"), the motor 33 is rotated to wind up and feed out the belt body 13. The winding amount and feeding amount of the belt body 13 change depending on the rotation amount of the motor 33 from the initial state. According to the change, the tension acting on the belt body 13 and the time during which the tension acts are adjusted, and an assist force corresponding to the tension and time is generated.

In other words, the amount of rotation of the motor 33 from the initial state affects the assist force. In order to control the amount of rotation of the motor 33, it is important to set an initial value of the phase of the motor 33. The amount of winding until the winding is completed by the activation unit 42a as described above differs depending on the user's physique (height). In other words, the amount of rotation of the motor 33 until the winding is completed differs depending on the user. Therefore, in the initial setting process, although a specific example will be explained later, the initial value of the phase of the motor 33 is set by the setting unit 42c.

[About initial setting process]
Initial setting processing by each functional unit included in the control unit 15 will be explained with reference to FIGS. 6 and 7. FIG. 7 is a flow diagram showing the initial setting process. After the initial setting process is performed, the assist device 10 generates an assist force according to the user's actual movement (work). Generation of the assist force will be explained later.

When the first attachment device 11 and the second attachment device 12 of the assist device 10 (see FIGS. 1 and 2) are attached to a predetermined part of the user's body, an initial setting process is disclosed (step S1 in FIG. 7). ). Note that in order to attach the first attachment tool 11 and the second attachment tool 12 to the user, the belt body 13 has been pulled out from the drive pulley 35 in advance, and the belt body 13 is in a slack state.

The user wearing the first wearing tool 11 and the second wearing tool 12 is in an upright posture. When the activation switch 41 is switched from the OFF state to the ON state by a user or the like, the activation unit 42a activates the actuator 14 and starts winding the belt body 13 (Step S2 in FIG. 7). That is, the motor 33 rotates and the belt body 13 is wound around the drive pulley 35. From the start of rotation of the motor 33, the belt body 13 is wound up by the first winding force. The current value supplied to the motor 33 to generate the first winding force is α [ampere].

The adjustment unit 42b acquires the detection signal of the rotation detector 36 every moment, and compares the detected value of the rotation speed (parameter related to rotation) of the motor 33 with the threshold value ε of the parameter (step S3 in FIG. 7). While the detected value is greater than or equal to the threshold ε, the current value supplied to the motor 33 is α [ampere], and the belt body 13 continues to be wound up by the first winding force.

When the detected value becomes less than the threshold ε (Yes in step S3 of FIG. 7), the adjustment section 42b estimates that winding of the belt body 13 is completed (step S4 of FIG. 7). When the detected value becomes less than the threshold ε, the adjustment unit 42b changes the current value supplied to the motor 33 to β [ampere] (step S5 in FIG. 7). The current value after the change, β [ampere], is less than or equal to the current value before the change, α [ampere], and in this embodiment is smaller than α [ampere] (β<α). Note that β [ampere] may be equal to or greater than zero, but in this embodiment, it is a value greater than zero.

Thereby, the winding force of the belt body 13 by the actuator 14 is changed to the second winding force. The second winding force after the change is less than or equal to the first winding force, and in this embodiment, is smaller than the first winding force. The second winding force is a winding force that generates tension in the belt body 13 to such an extent that the tension acting on the belt body 13 does not inhibit the user's movements and allows the user to move freely. Note that even if the user is in an upright position and the second winding force is zero, it is sufficient that tension is applied to the belt body 13. When β=0, the second winding force is zero. In this way, the adjustment unit 42b changes the winding force of the belt body 13 by the actuator 14 to the second winding force, which is smaller than the first winding force, by reducing the current supplied to the motor 33.

The timing at which the winding force is changed is the timing at which the slack in the belt body 13 is eliminated. As described above, the timing is detected by the rotation detector 36 based on parameters related to the rotation of the motor 33. In other words, when the first wearing tool 11 and the second wearing tool 12 are worn by the user, the motor 33 rotates the drive pulley 35, and the belt body 13 in a slack state is pulled around the drive pulley 35 by the first winding force. Wind it up. Eventually, the slack state of the belt body 13 is resolved. Then, the drive pulley 35 becomes unable to rotate, the rotational speed of the drive pulley 35 becomes slow, and its rotation eventually stops. Along with this, the rotational speed of the motor 33 also decreases, and its rotation eventually stops. This state is a state in which winding of the belt body 13 is completed. Therefore, the rotation detector 36 detects the timing at which the rotation speed (parameter related to rotation) of the motor 33 changes. In other words, the timing at which the rotation detector 36 detects that the rotational speed is less than the threshold value ε is the timing at which the winding force is changed.

Note that in the present disclosure, the rotation of the motor 33 is detected by the rotation detector 36, and the process of changing the winding force is executed based on this detection. However, the rotation of the drive pulley 35 may be detected by a rotation detector (not shown), and the process of changing the winding force may be executed based on the detection. That is, the adjustment unit 42b may detect (estimate) the completion of winding of the belt body 13 based on a parameter (for example, rotation speed) regarding the rotation of the motor 33 or the drive pulley 35. Then, the winding force is changed.

As described above, when the winding force of the belt body 13 is changed to the second winding force, the setting unit 42c sets the initial value of the phase (rotation angle) of the motor 33 (step S6 in FIG. 7). In the present disclosure, the phase (rotation angle) of the output shaft of the motor 33 at the time when the winding force is changed as described above is set to "zero" as an initial value (that is, reset).

Once the initial value is set, the amount of rotation of the motor 33 is thereafter controlled using the initial value as a reference. Thereby, the accurate amount of rotation of the motor 33 is managed in order to generate the assist force. The amount of rotation of the motor 33 corresponds to the amount of winding and the amount of feeding of the belt body 13 on the drive pulley 35 . The amount of winding of the belt body 13 is correlated with the magnitude of the tension acting on the belt body 13 and the time for which the tension acts, and as will be explained later, the tension of the belt body 13 generates an assisting force. Therefore, by accurately managing the amount of rotation of the motor 33, it is possible to generate a desired assist force.

[Change adjustment of the first winding force (winding speed of the belt body 13)]
As described above, in the initial setting process, when the motor 33 of the actuator 14 starts operating with the first wearing tool 11 and the second wearing tool 12 being worn by the user, the first winding force causes the belt to tighten. Winding up of the body 13 is performed. The winding force of the belt body 13 is generated based on the rotational torque of the drive pulley 35 included in the actuator 14, and the rotational torque is generated based on the output torque of the motor 33.
Therefore, the adjustment section 42b included in the control section 15 has a function of adjusting the winding force of the belt body 13. Specifically, the adjustment unit 42b changes the winding force of the belt body 13, that is, the output torque of the motor 33, by performing control to change the current supplied to the motor 33.

In the above description of the initial setting process, the current value supplied to the motor 33 is α [ampere] in order to generate the first winding force. Note that when winding of the belt body 13 is completed, the adjustment section 42b changes the current value supplied to the motor 33 to β [ampere] (where β<α).

Here, in the initial setting process, if the first winding force is large throughout, there is a possibility that the impact force transmitted from the belt body 13 to the user will become large when winding is completed. Therefore, when the operation of the motor 33 is started with the first attachment device 11 and the second attachment device 12 being attached to the user, the adjustment unit 42b changes the first winding force in a direction that reduces the first winding force. Take control.

In order to realize this control, the adjustment section 42b changes the current value (current command value) supplied to the motor 33. In other words, the current command value α [ampere] is variable. 10A and 10B are graphs showing temporal changes in the current value supplied to the motor 33 due to the function of the adjustment section 42. FIG. In the form shown in FIG. 10A, the adjustment unit 42 executes control to gradually reduce the current command value from the start of rotation of the motor 33 (time t0).
Further, as a modification thereof, as shown in FIG. 10B, control may be performed to reduce the current command value in stages from the start of rotation of the motor 33 (time t0).
As shown in FIGS. 10A and 10B, the adjustment unit 42b performs control to change the first winding force to be smaller in a time period after the start of winding than at the start.

In the form shown in FIGS. 10A and 10B, the current command value is set (programmed) so as to eventually approach γ [ampere]. Winding of the belt body 13 is completed when the current command value approaches γ [ampere] (for example, at time t1) or when the current command value approaches γ [ampere] and becomes constant (for example, time t2). When is detected, the adjustment unit 42b then changes the current command value to β [ampere]. Thereby, the winding force of the belt body 13 is changed to the second winding force, which is smaller than the initial value of the first winding force. As shown in FIG. 10A (FIG. 10B), the current command value β may be larger than the current command value γ, but β may be smaller than γ, or β may be the same as γ. good.

To explain from another point of view, the adjustment section 42b may have a function of adjusting the winding speed of the belt body 13. That is, the adjustment unit 42b may perform control to change the rotational speed of the motor 33. 11A and 11B are graphs showing changes over time in the rotational speed of the motor 33 due to the function of the adjustment section 42. FIG. In the form shown in FIG. 11A, the adjustment unit 42 executes control to gradually reduce the rotation speed of the motor 33 from the start of rotation (time t0).
As a modification thereof, as shown in FIG. 11B, control may be performed to gradually reduce the rotation speed of the motor 33 from the start of rotation (time t0).

In the form shown in FIGS. 11A and 11B, when the operation of the motor 33 of the actuator 14 is started with the first wearing tool 11 and the second wearing tool 12 being worn by the user, the adjustment part 42b Control is performed to change the winding speed of No. 13 in the direction of lowering it. Specifically, the adjustment unit 42b performs control to change the winding speed of the belt body 13 so that it is lower in a time period after the start of winding than at the start. When winding of the belt body 13 is completed (when winding completion is detected), the winding speed of the belt body 13 becomes zero.

In the initial setting process, when the motor 33 starts operating, the winding force of the belt body 13 is relatively large, and the winding speed of the belt body 13 is relatively high. Therefore, the length of the belt body 13 is automatically adjusted according to the user's physique (for example, height), and the process is quickly performed.
Then, by executing the control shown in FIGS. 10A and 10B, the first winding force becomes weak toward the completion of winding the belt body 13.
Furthermore, by executing the control shown in FIGS. 11A and 11B, the winding speed of the belt body 13 decreases toward completion of winding of the belt body 13.
As described above, it is possible to prevent impact force from being applied to the user from the belt body 13 when winding is completed.

[About the assist force by the assist device 10]
FIG. 8 is an explanatory diagram when the user wearing the assist device 10 changes his posture. In response to this change in posture, the assist device 10 can apply an assisting force to the user.

When the above initial setting process is completed and the first belt 16 is wound around the drive pulley 35 by the motor 33 of the actuator 14, the connecting member 18 pulls the second belt 17 toward the actuator 14, that is, upward. The second belt 17 has both ends 17a and 17d attached to the left and right second mounting tools 12. The second mounting tool 12 is fixed to the knee part BN. Therefore, when the first belt 16 is wound around the drive pulley 35, tension is applied to the first belt 16 and the second belt 17. This tension acts as an assist force for the user.

A case in which the user changes from an upright posture to a forward leaning posture will be explained. When the posture changes to a forward leaning posture, the actuator 14 sends out the belt body 13. Alternatively, the belt body 13 is unwound regardless of the power of the actuator 14. This allows the user to lean forward without straining. When the forward tilt angle of the user's upper body with respect to the vertical line reaches θ and the user stops at the forward tilt angle θ, the belt body 13 is stopped from being fed out (unwinding). Note that the start and end of the posture change can be detected by the rotation detector 36 or the sensor 38.

When the user starts changing his posture from a forward leaning posture to an upright posture, the actuator 14 winds up the belt body 13. As a result, tension is generated in the belt body 13. Due to this tension, a rearward acting force F1 is generated on the first mounting tool 11. In other words, an acting force F1 is generated in the direction of raising the upper body of the user who is leaning forward. At the same time, the tension of the second belt 17 generates an acting force F2 that pushes the left buttock and right buttock of the user forward. This allows the user to easily return from a forward leaning position to an upright position.

Further, as shown in FIG. 4, even when the user is in a bent posture (bent posture) with the upper body leaning forward and the knees bent, the assist device 10 applies an assisting force to the user. be able to. When the user changes from a bent position to an upright position, for example, when lifting an object or a part of the body of a person being assisted, the actuator 14 winds up the belt body 13. As a result, tension is generated in the belt body 13.

Due to this tension, a rearward acting force F1 is generated on the first mounting tool 11. In other words, an acting force F1 is generated in the direction of raising the upper body of the user who is leaning forward. At the same time, the tension of the second belt 17 generates an acting force F2 that pushes the left buttock and right buttock of the user forward. Further, a rearward acting force F3 is generated on the second mounting tool 12. The above-mentioned acting forces F1, F2, and F3 can reduce the muscular load on the back muscles, quadriceps femoris, and the like when the user bends forward, thereby assisting the user in lifting the load.

The assist device 10 functions even when the user changes from an upright posture to a bent posture. For example, the user may lift an object or a part of the person's body. In this case, the actuator 14 feeds out the belt body 13 while applying a braking force to the feeding of the belt body 13. That is, the motor 33 rotates in the direction of feeding out the belt body 13, but causes the motor 33 to generate torque in the winding direction. As a result, tension is generated in the belt body 13. In this case as well, the assist device 10 reduces the muscular load on the back muscles, quadriceps femoris, and the like in the forward bending posture of the user by using the acting forces F1, F2, and F3 as described above to assist the lifting motion. can do.
As described above, according to the assist device 10 of the present disclosure, it is possible to reduce the muscle burden on the lower back in a forward bending posture and prevent lower back pain.

Further, according to the assist device 10 of the present disclosure, even if the user is in a bent posture with one of the left and right legs BL in front and the other in the back (left-right asymmetrical state), the second belt One of the left second belt part 19 and the right second belt part 20 (the side from which the legs protrude in front) of the belt parts 17 can automatically become longer than the other. When the first belt 16 is wound up by the actuator 14 in this state, tension also acts on the second belt 17, and this tension acts on both the left second belt section 19 and the right second belt section 20, Tension does not escape. Therefore, as described above, even if the user is in an asymmetrical posture, the assist device 10 of the present disclosure makes it possible to apply an appropriate assist force to the user.

Even when the user maintains a forward leaning posture, the assist device 10 of the present disclosure allows the user to easily maintain that posture. That is, as shown in the diagram on the right side of FIG. 8, when the user is in the first forward leaning posture, the actuator 14 stops operating, making it impossible to feed out the belt body 13. Even if the user tries to take a further forward leaning posture (second forward leaning posture), the tension of the belt body 13 connecting the first wearing tool 11 and the second wearing tool 12 takes the second forward leaning posture. I can't. In other words, the assist device 10 attempts to maintain the user's first forward leaning posture. It becomes easy for the user to maintain the first forward leaning posture. As a result, the burden on the user's body is reduced, for example, when the user maintains the first forward-leaning posture for work for a long time.

[About the assist device 10 of the present disclosure]
As described above, the assist device 10 of the present disclosure (see FIG. 2) includes the first attachment tool 11 attached to the shoulder BS of the user, and the first attachment tool 11 attached to the left and right legs BL of the user. It includes two mounting tools 12, a belt body 13, and an actuator 14. The belt body 13 is provided along the back side of the user across the first wearing tool 11 and the second wearing tool 12. The actuator 14 is provided on the first mounting tool 11 and is configured to enable winding and feeding of a portion of the belt body 13.

The belt body 13 connects a first belt 16 that is wound up and fed out by an actuator 14, a second belt 17 that is attached to the second mounting tool 12, and the first belt 16 and the second belt 17. and a connecting member 18.

According to this assist device 10, the belt body 13 is provided along the back side of the user across the first wearing tool 11 and the second wearing tool 12. When the actuator 14 winds up the belt body 13 (first belt 16), tension is applied to the first belt 16 and the second belt 17. The tension creates an assisting force that assists the user's work, reducing the burden on the user's body.

For example, when a user (caregiver) shifts from a forward leaning posture to an upright posture while supporting a load (person being assisted) with his or her hands (see FIG. 6), the actuator 14 winds up the belt body 13, causing the belt Tension acts on the body 13. The tension makes it easier for the user to change from a forward-leaning posture to an upright posture, reducing the burden on the user's body. In other words, the tension acting on the belt body 13 by the actuator 14 is generated as an assist force.

The assist device 10 of the present disclosure includes a control unit 15 that controls the operation of the actuator 14 in order to execute the initial setting process as described above and to apply assist force to the user. The control unit 15 executes the following operation control for the initial setting process. That is, when the operation of the actuator 14 is started with the first wearing tool 11 and the second wearing tool 12 being worn by the user, the belt body 13 is wound up by the first winding force. When winding of the belt body 13 is completed, the winding force by the actuator 14 is changed to a second winding force that is smaller than the first winding force.

According to this initial setting process, even if the belt body 13 is loosened in advance when the user wears the assist device 10, when the actuator 14 starts operating, the belt body 13 is For example, the length will be automatically adjusted according to your height. When the winding of the belt body 13 is completed, the winding force is changed to a second winding force that is smaller than the first winding force. Since the second winding force is small, the user's movements are not hindered by the belt body 13 after the assist device 10 is attached.
Since the belt body 13 is adjusted to a length suitable for the user's physique, it is possible to generate an assisting force according to the user's physique.

In the present disclosure, in the initial setting process, when winding of the belt body 13 is completed, the control unit 15 (adjusting unit 15b) adjusts the winding force by the actuator 14 to a first winding force that is smaller than the first winding force and larger than zero. Change to 2 winding force. After changing the winding force, the state in which the motor 33 generates the rotational torque that generates the second winding force is maintained. In other words, the motor 33 always generates rotational torque in the direction in which the belt body 13 is wound up. However, as described above, the second winding force is a weak force, which is sufficient to provide tension to the belt body 13, and does not impose a burden on the user. Therefore, even if the user makes small movements such as losing his posture after wearing the assist device 10, the belt body 13 will not loosen easily.

The amount of winding of the belt body 13 by the first winding force during the initial setting process varies depending on the height of the user who wears the assist device 10. Furthermore, the amount of winding of the belt body 13 until the winding is completed varies depending on the length of the belt body 13 which has been set in a slack state in advance. Therefore, when the control unit 15 changes the winding force by the actuator 14 to the second winding force, the control unit 15 sets the phase of the motor 33 at the time of the change as the initial value of the phase of the motor 33. Thereby, the phase of the motor 33 is initially set according to the user's physique. Using this initial setting as a reference, it becomes possible to control the rotation of the motor 33 in order to generate the assist force. As a result, the winding amount of the belt body 13 (first belt 16) can be accurately controlled, and an appropriate assist force can be generated.

As described in FIG. 5, the actuator 14 includes a motor 33, a reduction gear unit 34, and a drive pulley 35. The speed reducer section 34 is composed of a plurality of gears 34g, and outputs the reduced rotation speed of the motor 33. The drive pulley 35 can take up the belt body 13 by rotating due to the output of the reduction gear unit 34 .
When the belt body 13 is wound around the drive pulley 35, the motor 33 applies torque in one direction to the drive pulley 35 through the reducer section 34, so that the drive pulley 35 rotates in the direction in which the belt body 13 is wound up.

Further, for example, when the belt body 13 is pulled by an external force due to a change in the posture of the user and is sent out from the drive pulley 35, the control unit 15 rotates the motor 33 as follows to cause the drive pulley 35 to Torque is applied to the drive pulley 35, and the drive pulley 35 rotates. That is, when the belt body 13 is sent out from the drive pulley 35, the motor 33 applies a torque in the direction of winding up the belt body 13 to the drive pulley 35 through the reducer section 34, and the drive pulley 35 sends out the belt body 13. Rotate in the direction.

In this way, whether the belt body 13 is wound around the drive pulley 35 or the belt body 13 is sent out from the drive pulley 35, the direction in which the motor 33 generates torque is the same. The control unit 15 controls the motor 33 to generate torque in the direction of winding the belt body 13 .

According to this configuration, tension acts on the belt body 13 both when the belt body 13 is wound up and when the belt body 13 is fed out. Therefore, the belt body 13 does not loosen when the assist device 10 is worn by the user. That is, tension is always applied to the belt body 13 in the direction in which the belt body 13 is wound up.
When the belt body 13 is fed out, the rotation direction of the gear 34g included in the reducer section 34 is the opposite direction to the direction in which the belt body 13 is wound up. In this case, between the meshing gears 34g and 34g, only one side of the teeth of one gear 34g is in contact with the teeth of the other gear 34g. In other words, the teeth of the meshing gears 34g, 34g always touch each other on the same surface. Therefore, even if the backlash is large, it does not affect the responsiveness regarding assist force generation.

In this way, regardless of whether the belt body 13 is wound up or sent out, according to the configuration, the assist force due to the backlash between the gears 34g, 34g in the reducer section 34 is reduced. It is possible to prevent a delay in response, and it is also possible to prevent the occurrence of an impact due to backlash.
Furthermore, as described above, it is possible to increase the backlash to some extent between the gears 34g, 34g of the reducer section 34, so it is not necessary to increase the precision of the gears so much. As a result, it is possible to reduce the manufacturing cost of the gear 34g that constitutes the reducer section 34. Note that the gear 34g included in the reduction gear unit 34 may be other than a spur gear, and may be a helical gear, a double helical gear, or the like.

In the initial setting process, as described with reference to FIGS. 10A and 10B, the control unit 15 controls the operation of the actuator 14 (motor 33) while the first wearing tool 11 and the second wearing tool 12 are worn by the user. When the first winding force is started, control is performed to change the first winding force in a time period after the start of winding so as to be smaller than that at the start. With this configuration, the first winding force becomes weak toward the completion of winding the belt body 13. Therefore, when winding is completed, it is possible to prevent impact force from being applied to the user from the belt body 13.

Further, as described with reference to FIGS. 10A and 10B, the control unit 15 starts the operation of the actuator 14 (motor 33) when the first wearing tool 11 and the second wearing tool 12 are worn by the user. Then, the winding speed of the belt body 13 may be controlled to be lower than that at the start of winding in a time period after the start of winding. In this case, the winding speed of the belt body 13 decreases toward completion of winding of the belt body 13. Therefore, when winding is completed, it is possible to prevent impact force from being applied to the user from the belt body 13.

[Other assist device 10]
In the assist device 10 disclosed above, the second attachment tool 12 is attached to the user's leg BL. As shown in FIG. 9, the second wearing tool 12 may be worn on the user's waist BW. In this case, the second wearing tool 12 may be in the form of a waist belt or in the form of pants. When the second wearing tool 12 is attached to the waist BW, the actuator 14 may be attached to the first wearing tool 11 or may be attached to the second wearing tool 12. In FIG. 9 , the actuator 14 is attached to the first mounting tool 11 .

Also in the case of the assist device 10 shown in FIG. 9, the belt body 13 is provided along the back side of the user across the first wearing tool 11 and the second wearing tool 12. When the actuator 14 winds up the belt body 13, tension is applied to the belt body 13. The tension creates an assisting force that assists the user's work, reducing the burden on the user's body.

〔others〕
In order to prevent and prevent lower back pain for the user, it is preferable that the second attachment tool 12 be attached to the leg BL. This is because the burden on the lower back BW is reduced by attaching the second mounting tool 12 to the leg BL.
In each type of assist device 10, the belt body 13 is lightweight, can follow the user's body even when the user changes posture, and follows the user's movements. Therefore, the assist device 10 that is comfortable to wear can be obtained.
In the above disclosure, the control box 30 is provided on the rear side (back side) of the user in the first mounting tool 11, but it may be provided on the front side of the user. In this case, the belt body 13 is provided along the back of the user via the user's shoulder BS.

The linear form of the belt body 13 may be other than the illustrated form. For example, although not shown, a rotary pulley is provided in the first attachment part 27 of the connecting member 18 as well as in the second attachment part 28, and the first belt 16 is folded back in the middle of the rotation pulley. It may be hung on In this case, the end of the first belt 16 (opposite to the drive pulley 35 side) is attached to the first mounting tool 11 (base 31).
Alternatively, although not shown, a rotating pulley may be attached to the second mounting tool 12, and the second belt 17 may be folded back halfway and hung on the rotating pulley. In this case, both ends of the second belt 17 are attached to a mounting tool (third mounting tool) that is mounted on the waist BW.

The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims.

[Additional note]
In the assist device 10 of the embodiment, when the user wears the first wearing tool 11 and the second wearing tool 12 and the operation of the actuator 14 is started, the control unit 15 controls the belt body by the first winding force. 13 is performed, and when the winding of the belt body 13 is completed, control is performed to change the winding force by the actuator 14 to a second winding force that is smaller than the first winding force.
However, as a reference invention, there is an assist device in which such control is not performed.
That is, the assist device of the reference invention is as follows. In addition, in the assist device of the following reference invention, the same code|symbol is attached|subjected to the same structure as the assist device 10 of the said embodiment.

The assist device 10 of the reference invention (see FIG. 2) includes:
A first attachment tool 11 that is attached to at least one of the user's shoulder BS and chest BB;
a second wearing tool 12 that is attached to each of the left and right legs BL or waist BW of the user;
a belt body 13 provided along the back side of the user across the first mounting tool 11 and the second mounting tool 12;
an actuator 14 provided on the first mounting tool 11 or the second mounting tool 12 and capable of winding up and feeding out a part of the belt body 13;
Equipped with
The actuator 14 (see FIG. 5) includes a motor 33, a reducer section 34 that is composed of a plurality of gears 34g, and that decelerates and outputs the rotation of the motor 33; a pulley 35 capable of winding up the belt body 13 by
When the belt body 13 is sent out from the pulley 35, the motor 33 applies a torque in the direction of winding up the belt body 13 to the pulley 35 through the reduction gear unit 34, and the pulley 35 continues to feed out the belt body. 13 in the direction to send it out.

Each of the configurations disclosed above can be applied to the assist device of the reference invention.

10: Assist device 11: First mounting tool 12: Second mounting tool 13: Belt body 14: Actuator 15: Control section 33: Motor 34: Reducer section 35: Drive pulley (pulley)
BS: Shoulder BB: Chest BL: Legs BW: Waist

Claims (8)

a first attachment device attached to at least one of the user's shoulder and chest;
a second attachment device attached to each of the left and right legs or waist of the user;
a belt body provided along the back side of the user across the first mounting tool and the second mounting tool;
an actuator that is provided on the first mounting tool or the second mounting tool and that enables winding and feeding of a part of the belt body;
a control unit that executes operation control of the actuator;
Equipped with
The control unit includes:
When the operation of the actuator is started with the first wearing tool and the second wearing tool being worn by the user, the belt body is wound up by a first winding force, and the belt body is When the winding is completed, the winding force by the actuator is changed to a second winding force smaller than the first winding force.
Assist device. When the winding of the belt body is completed, the control unit changes the winding force by the actuator to a second winding force that is smaller than the first winding force and larger than zero. assist device. The actuator has a pulley capable of winding up the belt body, and a motor for causing the pulley to wind up the belt body,
The assist device according to claim 1 or 2, wherein the control unit detects completion of winding of the belt body based on a parameter related to rotation of the pulley or the motor. The actuator has a pulley capable of winding up the belt body, and a motor for causing the pulley to wind up the belt body,
The assist device according to any one of claims 1 to 3, wherein the control unit changes the winding force by the actuator by reducing the current supplied to the motor. The actuator has a pulley capable of winding up the belt body, and a motor for causing the pulley to wind up the belt body,
The control unit, when changing the winding force by the actuator to the second winding force, sets the phase of the motor at the time of the change as an initial value of the phase of the motor. 4. The assist device according to any one of 4. The actuator includes a motor, a reducer section that is composed of a plurality of gears and that decelerates and outputs the rotation of the motor, and is capable of winding the belt body by rotating due to the output of the reducer section. has a pulley,
When the belt body is sent out from the pulley, the motor applies torque to the pulley through the reduction gear unit in a direction to wind up the belt body, and the pulley rotates in a direction to send out the belt body. The assist device according to any one of claims 1 to 4. When the operation of the actuator is started, the control unit performs control to change the first winding force to be smaller in a time period after the start of winding than at the start. The assist device according to any one of claims 1 to 6. When the operation of the actuator is started, the control unit controls the winding speed of the belt body to be lower than that at the start of winding in a time period after the start of winding. The assist device according to any one of claims 1 to 7, wherein the assist device performs the following.

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