Auxiliary device

Abstract

The invention relates to an auxiliary device. An assist device (10) is provided with: an actuator (14) that applies an assist force to a user by applying a winding force corresponding to a command value to a belt body (13); an inertial sensor (38) for detecting the inclination angle of the upper body; a rotation angle sensor (36) that detects the operating position of the actuator (14); and a control unit (40) that finds the command value. The command value is a value obtained by adding the main assist command value and the additional assist force command value. The control unit (40) executes: a process for obtaining a main assist command value on the basis of the inclination angle of the upper body; a process for obtaining an estimated motor rotation angle amount (d [phi] E) on the basis of the inclination angle of the upper body; and a process for obtaining an additional assist force command value on the basis of the position difference ([delta] [phi]) between the detected motor rotation angle ([phi] D) detected by the rotation angle sensor (36) and the estimated motor rotation angle ([phi] E) based on the estimated motor rotation angle amount (d [phi] E).

Description

TECHNICAL FIELD

[0001] The present application relates to an assist device. BACKGROUND

[0002] For example, an assist device is disclosed in Patent Literature 1, which includes a first wearing member to be worn on an upper body of a user, a second wearing member to be worn on left and right leg portions of the user, a belt to be provided along a back surface side of the user between the first wearing member and the second wearing member, and an actuator to be provided to the first wearing member.

[0003] The assist device generates tension in the belt by winding a portion of the belt with the actuator. The tension acts on the user as an assist force that assists rotation of the user's thigh portions.

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2021-49601

[0005] In the assist device described above, the belt acts in a manner to be wound by the actuator and to be fed out from the actuator so as to follow a change in posture of the user.

[0006] However, the belt that acts in a state along the back surface side of the user sometimes gets caught or generates friction with clothes of the user. Such catching or friction can hinder the action of the belt, and can possibly degrade followability of the belt to the change in posture of the user.

[0007] If the followability of the belt is degraded, there is a case where timing of acting the assist force on the user is deviated, and the belt gets caught in a shoulder or a back of the user. As a result, the user's sense of use can be impaired. SUMMARY

[0008] An assist device according to an embodiment includes a first wearing member to be worn on an upper body of a user, a second wearing member to be worn on left and right leg portions of the user, a belt to be provided across the first wearing member and the second wearing member and along a back surface of the user, an actuator to be provided to the first wearing member, which is capable of a winding action on a portion of the belt and a feeding-out action, and which causes an assist force to act on the user by applying a winding force corresponding to a command value to the belt, a first sensor to detect an inclination angle of the upper body, a second sensor to detect a position of an action of the actuator, and a control portion to calculate the command value. The command value is a value obtained by adding a first command value to a second command value. The control portion performs a process to calculate the first command value based on the inclination angle of the upper body, a process to calculate an estimated value of an action amount of the actuator based on the inclination angle of the upper body, and a process to calculate the second command value from a difference between the position of the action of the actuator detected by the second sensor and an estimated position of the actuator based on the estimated value of the action amount.

[0009] According to the present disclosure, the followability of the belt can be inhibited from decreasing. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a rear view of the assist device according to the embodiment.

[0011] Figure 2 is a rear view of the assist device mounted on the user's body.

[0012] Figure 3 is a side view of the assist device mounted on the user's body.

[0013] Figure 4 is a diagram showing the inside of the control box.

[0014] Figure 5 is a block diagram showing the control structure of the assist device.

[0015] Figure 6 is an explanatory diagram of a case where the user wearing the above-described assist device changes the posture.

[0016] Figure 7 is a functional block diagram showing one example of the operation processing of the current command value possessed by the control section.

[0017] Figure 8 is a block diagram showing one example of the main assist force operation section.

[0018] Figure 9 is a block diagram showing one example of the estimated rotation angle operation section.

[0019] Figure 10 is a block diagram showing one example of the additional assist force operation section.

[0020] Figure 11A is a diagram showing the results of the assist device verification test according to the above-described embodiment, and is a diagram showing the relationship between the inclination angle and the motor current.

[0021] Figure 11B is a diagram showing the results of the assist device verification test according to the above-described embodiment, and is a diagram showing the relationship between the inclination angle and the motor rotation angle.

[0022] Figure 12 is a diagram showing the relationship between the inclination angle and the motor rotation angle when the control is performed only by the main assist command value. DETAILED DESCRIPTION

[0023] First, the content of the embodiment will be explained.

[0024] [SUMMARY OF THE EMBODIMENT]

[0025] (1) An assistive device as an embodiment includes: a first wearing member to be worn on an upper body of a user; a second wearing member to be worn on left and right leg portions of the user; a belt to be disposed across the first wearing member and the second wearing member and along a back of the user; an actuator to be disposed at the first wearing member, capable of performing a winding action and a feeding action on a part of the belt, and applying an assistive force to the user by applying a winding force corresponding to a command value to the belt; a first sensor to detect an inclination angle of the upper body; a second sensor to detect a position of the actuator; and a control unit to calculate the command value. The command value is a value obtained by adding a first command value to a second command value. The control unit performs: a process to calculate the first command value based on the inclination angle of the upper body; a process to calculate an estimated value of an action amount of the actuator based on the inclination angle of the upper body; and a process to calculate the second command value from a position difference between the position of the actuator detected by the second sensor and an estimated position of the actuator based on the estimated value of the action amount.

[0026] According to the above structure, the second command value included in the command value is calculated from the position difference between the position of the actuator detected by the second sensor and the estimated position of the actuator based on the inclination angle. The position difference is a value indicating whether the belt follows the posture of the user. In a case where the position difference is large, if the control unit controls to increase the second command value so that the position difference becomes small, the winding force of the actuator can be increased to a degree at which hooking, friction, or the like generated between the user and the belt can be eliminated, as a result of which the followability of the belt can be suppressed from decreasing.

[0027] (2) In the assistive device, preferably, the process to calculate the estimated value of the action amount includes: a process to hold a maximum value of the inclination angle within a prescribed period; a process to calculate an inclination angle difference between the maximum value of the inclination angle and a current inclination angle; and a process to calculate the estimated value of the action amount based on the inclination angle difference.

[0028] In this case, the inclination angle difference indicates an angle difference between the upper body at the maximum forward inclination and the current upper body. In other words, the inclination angle difference indicates the angle of the upper body when the maximum value of the inclination angle is used as a reference. Thus, the reference can be appropriately set with respect to the inclination angle that gradually changes according to the change in the posture of the user.

[0029] (3) In addition, in the assistive device, preferably, the estimated position of the actuator is a position obtained by moving the maximum position of the actuator at which the inclination angle is the maximum value by the estimated value of the action amount.

[0030] In this case, the estimated operation position of the actuator is calculated as an operation position based on the maximum operation position.

[0031] (4) In the above-described assist device, the second command value is calculated based on proportional integral control of the operation amount difference.

[0032] In this case, the second command value can be appropriately calculated based on the operation amount difference.

[0033] (5) In addition, in the above-described assist device, the actuator has a pulley that winds a portion of the belt and a motor that drives the pulley, and the operation position can also be a rotation angle of the motor.

[0034] [Details of Embodiments]

[0035] Hereinafter, a preferred embodiment will be described with reference to the drawings.

[0036] [Overall Structure of Assist Device 10]

[0037] Figure 1 is a rear view of the assist device according to the embodiment. Figure 2 is a rear view of the assist device mounted on the body of the user. Figure 3 is a side view of the assist device mounted on the body of the user.

[0038] In the assist device 10 of the present disclosure, left and right are left and right for a user who wears the assist device 10 in an upright posture, front and back are front and back for the user, and up and down are up and down for the user. Up is the head side of the user, and down is the foot side of the user.

[0039] Figure 1 The assist device 10 illustrated has one first wearing member 11 and two second wearing members 12.

[0040] The first wearing member 11 is worn on the left and right shoulder portions BS that are a part of the body of the user (person). The first wearing member 11 can be worn on the upper body of the user such as the shoulder portions and the chest of the user, and can also be other than the illustrated form.

[0041] The second wearing member 12 is worn on the left and right leg portions BL that are other parts of the body of the user. In the present disclosure, the second wearing member 12 is worn on the knee portions BN inside the leg portions BL. The second wearing member 12 on the left side is symmetrical with the second wearing member 12 on the right side, but the structures are the same. The second wearing member 12 can also be other than the illustrated form.

[0042] The first wearable piece 11 and the two second wearable pieces 12 are worn at two separate locations separated by the waist (BW) and hip joint, in other words, they are worn at the shoulder (BS) and leg (BL).

[0043] The first wearable piece 11 has a base 21, a pair of shoulder straps 22 and a pair of armpit straps 23.

[0044] The base 21 includes a control box 30 that houses the control device 15, which will be described later.

[0045] The base 21 is carried by the user via a pair of shoulder straps 22 and a pair of armpit straps 23.

[0046] A pair of shoulder straps 22 are provided on the upper part of the base 21 (control box 30). A pair of armpit straps 23 are connected to the front end 22a of each pair of shoulder straps 22.

[0047] A pair of armpit straps 23 connect the base 21 (control box 30) and the front ends 22a of a pair of shoulder straps 22. The length of the armpit straps 23 is adjustable. By adjusting the length of the armpit straps 23, the base 21 is made to fit snugly against the user's back (back) BB. Thus, the first wear piece 11 is worn on the shoulder BS in a manner that prevents it from moving forward, backward, left, right, or up and down.

[0048] For example, the first wearing member 11, as a part that hangs on the shoulder (BS), may also include a rigid component. Although not shown, the first wearing member 11 may also have a component (belt) that is worn on the user's waist (BW) as an accessory. The aforementioned belt is connected to the base 21.

[0049] The second wearable part 12 is made of a soft fabric or the like.

[0050] The second wearable piece 12 includes a knee body 24 worn on the user's knee BN, and a pair of knee straps 25 extending from the knee body 24. The pair of knee straps 25 are respectively wrapped around the upper and lower positions of the knee BN. The front ends of the pair of knee straps 25 are fixed to the knee body 24. The wrapping length of the knee straps 25 relative to the knee BN can be adjusted by a locking member such as a strap and buckle or a face-fitting member. As a result, the knee body 24 is in a state of close contact with the rear side of the knee BN. The second wearable piece 12 is worn on the knee BN in a manner that prevents it from moving in the front-back, left-right, and up-down directions.

[0051] In addition to the first wearable piece 11 and the left and right second wearable pieces 12, the auxiliary device 10 also includes a belt 13, an actuator 14, a control device 15, a battery 37, and an inertial sensor 38.

[0052] The strap 13 is disposed along the back side of the user. The strap 13 connects the first wearer 11 and the second wearer 12.

[0053] The belt body 13 has a first belt 16, a second belt 17, and a connecting member 18. The first belt 16 is located on the upper body side of the user. The second belt 17 is located on the lower body side of the user. The connecting member 18 connects the first belt 16 and the second belt 17.

[0054] The first band 16 and the second band 17 are both long and flexible. The connecting member 18, though to be described later, is, for example, composed of a rectangular ring 27 referred to as a "flat can" or "square can" and fasteners 28 such as buckles.

[0055] The first band 16 and the second band 17 are cloth or leather band-like components that can be bent to follow the shape of the body. Alternatively, the first band 16 and the second band 17 can also be rope-like bands (like threads). The first band 16 and the second band 17 of this disclosure are formed of a non-stretchable material. That is, the first band 16 and the second band 17 have the characteristic of not easily stretching or contracting along their long sides, or are non-stretchable.

[0056] The actuator 14, control device 15, battery 37 and inertial sensor 38 are housed in the control box 30 of the seat housing.

[0057] Figure 4 This is a diagram showing the interior of the control box 30. The control box 30 has a back panel 31 and a cover 32 that covers the back panel 31. Figure 4 In the middle, cover 32 is shown by an imaginary line (double-dotted line).

[0058] An opening (cut) 32a is provided at the lower end of the cover 32. The first belt 16 passes through the opening 32a.

[0059] The actuator 14 is capable of winding a portion of the belt 13 and discharging a portion of the belt 13. In other words, the actuator 14 causes the belt 13 to extend and retract between the first wearer 11 and the second wearer 12.

[0060] Actuator 14 applies an auxiliary force to the user by applying a winding force to the belt 13.

[0061] The actuator 14 includes a motor 33, a reducer 34, and a drive pulley 35.

[0062] Motor 33 is a brushless DC motor. Motor 33 has a rotating shaft 33a. The rotating shaft 33a rotates at a specified torque and a specified speed based on the current command value obtained by the control device 15.

[0063] The rotation angle of the rotating shaft 33a of motor 33, i.e., the motor rotation angle (operating position), is detected by rotation angle sensor 36. Rotation angle sensor 36 is installed in motor 33. The rotation angle sensor 36 of this disclosure is a Hall sensor for rotation control of motor 33. Rotation angle sensor 36 can also be a rotary encoder or a resolver. The output of rotation angle sensor 36 is given to control device 15.

[0064] The speed reducer 34 is composed of multiple gears. The speed reducer 34 reduces the rotational speed of the motor 33 and rotates the output shaft 34a of the speed reducer 34.

[0065] The drive pulley 35 is connected to the output shaft 34a in a manner that allows it to rotate as a single unit. One end 16a of the first belt 16 is fixed to the drive pulley 35.

[0066] If 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. If the drive pulley 35 rotates in the other direction due to the reverse rotation of the motor 33, the first belt 16 is discharged from the drive pulley 35.

[0067] In this way, actuator 14 can wind and deliver a portion of the belt 13, namely the first belt 16.

[0068] The control device 15 may include, for example, a computer, a drive circuit for the motor 33, etc.

[0069] The control device 15 has the function of controlling the actuator 14 based on the output of the rotation angle sensor 36 and the output of the inertial sensor 38. The processing performed by the control device 15 will be described later.

[0070] The inertial sensor 38 includes, for example, at least a three-axis accelerometer. The output of the inertial sensor 38 is given to the control device 15. In addition to the accelerometer, the inertial sensor 38 may also include an angular velocity sensor and a gyroscope. The inertial sensor 38 can output information indicating the attitude of the control box 30. The inertial sensor 38 may also be located externally to the control box 30.

[0071] The storage battery 37 supplies power to various parts of the control device 15, motor 33 and other auxiliary devices.

[0072] [Body 13]

[0073] As described above, the belt body 13 has a first belt 16, a second belt 17, and a connecting member 18. One end 16a of the first belt 16 is wound and fixed to the drive pulley 35. The other end 16b of the first belt 16 is fixed to the connecting member 18. If the first belt 16 is wound around the drive pulley 35, the connecting member 18 is pulled up. If the connecting member 18 is forcibly pulled down, the first belt 16 is fed out (pulled out) from the drive pulley 35.

[0074] There is a correlation between the amount of winding or feeding (pulling out) of the first belt 16 in the drive pulley 35 and the amount of rotation of the output shaft of the motor 33. Therefore, the amount of winding or feeding of the first belt 16 can be obtained based on parameters related to the rotation of the motor 33.

[0075] like Figure 4 As shown, the connecting member 18 includes an annular body 27 and a fastener (buckle) 28. The fastener 28 has a first member 28a and a second member 28b. The first member 28a and the second member 28b are separable and connectable. The first member 28a is mounted to the other end 16b of the first belt 16. The second member 28b and the annular body 27 are connected by a short belt 29. The second belt 17 is inserted into the annular body 27.

[0076] The second belt 17 folds back within the annular body 27 and hangs on the annular body 27. The annular body 27 supports the folded-back second belt 17. Thus, the second belt 17 is supported by the annular body 27 but is not fixed to it. Therefore, the second belt 17 can move in both directions along its long side ( Figure 4 Move in the X direction (of the arrow).

[0077] like Figure 1 as well as Figure 2 As shown, the second strap 17 is mounted on the second wearable member 12. Specifically, the second strap 17 is strap-shaped. One end 17a of the second strap 17 is mounted on the left side of the second wearable member 12. The other end 17d of the second strap 17 is mounted on the right side of the second wearable member 12. The middle portion 17c of the second strap 17 is attached to the connecting member 18.

[0078] In addition to the midway portion 17c, the second belt 17 also includes a left leg belt portion 19 extending from the connecting member 18 (midway portion 17c) to the left side of the second wear member 12, and a right leg belt portion 20 extending from the connecting member 18 (midway portion 17c) to the right side of the second wear member 12.

[0079] As described above, since the second strap 17 is not fixed to the ring 27, the lengths of the left leg strap 19 and the right leg strap 20 can be freely changed. However, the combined length of the left leg strap 19 and the right leg strap 20 is constant. According to this structure, for example, the user's walking is not restricted by the second strap 17, and the user can walk happily.

[0080] The second belt 17 also has a connecting member 39. The connecting member 39 connects the left leg belt portion 19 and the right leg belt portion 20.

[0081] When the user changes posture, the connecting member 39 prevents the left leg strap 19 and the right leg strap 20 from increasing in lateral distance. That is, the connecting member 39 prevents the left leg strap 19 and the right leg strap 20 from not following the back side of the user's leg BL.

[0082] [Control device 15 controls the auxiliary force]

[0083] Figure 5 This is a block diagram representing the control structure of the auxiliary device 10.

[0084] like Figure 5 As shown, a rotation angle sensor 36 and an inertial sensor 38 are connected to the control device 15. The control device 15 controls them and acquires the outputs from the rotation angle sensor 36 and the inertial sensor 38.

[0085] The control device 15 includes a control unit 40 consisting of a computer or the like and a drive circuit (motor driver) 42.

[0086] The drive circuit 42 controls the operation of the motor 33 based on the current command value given by the control unit 40.

[0087] The control unit 40 includes a processing unit 40a consisting of a CPU (Central Processing Unit) and the like, and a storage unit 40b consisting of a memory, a hard disk and the like.

[0088] The processing unit 40a performs various processes based on the various programs and parameters stored in the storage unit 40b.

[0089] The processing unit 40a controls the actuator 14 based on the current command value. The processing unit 40a has the function of performing an arithmetic processing 40a1 that calculates the current command value. The processing unit 40a provides the current command value to the drive circuit 42. The current command value is a command used to control the motor 33 (actuator 14). The current command value indicates the current value that should be supplied to the actuator 14. The current command value is calculated based on the output of the rotation angle sensor 36 and the output of the inertial sensor 38. The processing unit 40a provides the current command value to the drive circuit 42.

[0090] The drive circuit 42 supplies power to the motor 33 according to the current command value, causing the motor 33 to operate. As a result, the actuator 14 generates an auxiliary force corresponding to the user's posture. As a result, the processing unit 40a controls the auxiliary force corresponding to the user's posture.

[0091] The control of the auxiliary force performed by the processing unit 40a (control unit 40) will be described below.

[0092] The control unit 40 calculates the tilt angle of the upper body based on the output of the inertial sensor 38. The tilt angle of the upper body refers to the angle of the user's upper body relative to a certain reference position. The inertial sensor 38 is installed on the user's upper body. Therefore, the control unit 40 can calculate the tilt angle of the upper body based on the output of the inertial sensor 38. In other words, the inertial sensor 38 constitutes the first sensor for detecting the tilt angle of the user's upper body.

[0093] Furthermore, the control unit 40 determines the operating position of the actuator 14 (motor 33) based on the output of the rotation angle sensor 36. The control unit 40 determines the motor rotation angle as the operating position of the actuator 14. In other words, the rotation angle sensor 36 constitutes a second sensor for detecting the operating position of the actuator 14.

[0094] In the following description, the motor rotation angle obtained based on the output of the rotation angle sensor 36 will also be referred to as the detected motor rotation angle.

[0095] When the user is in an upright position, the control unit 40 controls the actuator 14 not to apply winding force to the belt 13. Therefore, in this case, the auxiliary force will not act on the user.

[0096] Furthermore, when the user is in an upright position, the actuator 14 can be controlled to apply a very weak winding force to the belt 13. Thus, when the user is in an upright position, excessive slack in the belt 13 can be prevented.

[0097] Figure 6 This is an explanatory diagram showing a user changing posture while wearing the aforementioned assistive device 10. Figure 6 The image shows users in an upright posture and users in a forward-leaning posture.

[0098] An upright posture refers to a posture in which the user's upper body and thighs are almost vertical. Conversely, a forward-leaning posture refers to a posture in which the user's upper body leans forward with their knees almost completely straight.

[0099] Here, for Figure 6 The text describes how users change their posture between an upright position and a forward-leaning position.

[0100] First, when the user in an upright position begins to change posture towards a forward-leaning posture, the belt 13 is pulled out from the drive pulley 35 by the tension of the belt 13 caused by the posture change. In other words, the belt 13 is forcibly delivered from the actuator 14.

[0101] like Figure 6 As shown, the tilt angle θ ranges from 0° to θ1, and the forward tilt posture is maintained when the tilt angle θ is θ1.

[0102] Figure 6 The tilt angle θ shown is the angle of the user's upper body UB when it is positioned along the vertical line VL. When the tilt angle θ is near 0°, the user's posture is upright. When the tilt angle θ is greater than 0°, the user's posture is forward-leaning.

[0103] Furthermore, in this embodiment, the tilt angle θ is also the bending angle between the upper body and the thigh.

[0104] During the period when the user is in a forward-leaning posture, the actuator 14 applies a winding force to the belt 13 corresponding to the tilt angle θ.

[0105] exist Figure 6 In a forward-leaning posture, if the actuator 14 (motor 33) applies a winding force to the first belt 16, the connecting member 18 pulls the second belt 17 toward the actuator 14 side, i.e., the upper side. The two ends 17a and 17d of the second belt 17 are mounted on the left and right second wear members 12. The second wear members 12 are fixed to the knee BN.

[0106] Therefore, when a winding force is applied to the first belt 16, tension acts on both the first belt 16 and the second belt 17. This tension functions as an auxiliary force (assistance force) for the user.

[0107] This tension causes the first wear piece 11 to generate a rearward force F1. In other words, it generates a force F1 in the direction that lifts the upper body of the user in a forward-leaning posture. At the same time, the aforementioned tension causes the second belt 17 to generate a force F2 that pushes the user's left and right hips forward.

[0108] In other words, the actuator 14 generates an auxiliary force between the first wearer 11 and the second wearer 12 to assist in the rotation of the thigh.

[0109] Therefore, it becomes easier for the user to maintain a forward-leaning posture and return to an upright posture, which can reduce the muscle load on the user's back muscles and quadriceps, thus assisting the user's movements.

[0110] When the user is in a forward-leaning posture, the actuator 14 continuously applies a winding force to the belt 13. Thus, tension is continuously applied to the belt 13.

[0111] Therefore, when a user in a forward-leaning posture begins to change posture towards becoming upright, the belt 13 is wound around the actuator 14 by the winding force of the actuator 14.

[0112] Therefore, the belt 13 moves in a way that follows the user's posture changes.

[0113] Since the belt 13 moves in a manner that follows the user's posture changes, in principle, the amount of winding and feeding of the belt 13 by the drive pulley 35 is related to the tilt angle θ of the user's upper body. Furthermore, it can be said that when the belt 13 is fed out, the motor rotation angle of the motor 33 increases according to the amount of feeding, and when the belt 13 is wound, the motor rotation angle of the motor 33 decreases according to the amount of winding.

[0114] Therefore, there is also a correlation between the motor rotation angle and the tilt angle θ of motor 33.

[0115] As described above, the motor rotation angle of motor 33 is the amount of action of actuator 14. In other words, there is a correlation between the amount of action of actuator 14 and tilt angle θ.

[0116] Therefore, the control unit 40 can estimate the motor rotation angle (operating position of actuator 14) based on the tilt angle θ.

[0117] This will be discussed in detail later.

[0118] As described above, the control unit 40 uses the output of the rotation angle sensor 36 and the output of the inertial sensor 38 to determine the current command value, and then provides the current command value to the drive circuit 42. Thus, the control unit 40 controls the actuator 14.

[0119] The actuator 14 operates based on the motion control of the drive circuit 42 given a current command value, and applies an auxiliary force to the user by applying a winding force corresponding to the current command value to the tape 13.

[0120] [Calculation and processing of current command values]

[0121] Figure 7 This is a functional block diagram representing an example of the calculation and processing of current command values ​​by the control unit 40.

[0122] The control unit 40 performs calculations in the calculation process 40a1 using the user's tilt angle θ and the detection motor rotation angle φD.

[0123] As described above, the motor rotation angle φD is the motor rotation angle of motor 33 (operating position of actuator 14) detected by rotation angle sensor 36.

[0124] The user's tilt angle θ and the detection motor rotation angle φD are obtained by the control unit 40 as discrete time series data during the operation of the auxiliary device 10.

[0125] The tilt angle θ is given to the main auxiliary force calculation unit 50. The main auxiliary force calculation unit 50 calculates the main auxiliary force command value based on the tilt angle θ.

[0126] In addition, Figure 7 In the process, the control unit 40 calculates the relative values ​​of the tilt angle θ and the rotation angle φD of the detection motor.

[0127] Figure 8 This is a block diagram representing an example of the main auxiliary force calculation unit 50.

[0128] The tilt angle θ of the auxiliary force calculation unit 50 is given to the multiplier 50a and the differentiator 50b.

[0129] Multiplier 50a multiplies the tilt angle θ by the proportional gain Kp1. The output of multiplier 50a is fed to adder 50c in the subsequent stage.

[0130] Differentiator 50b outputs angular velocity ω1 by differentiating the tilt angle θ.

[0131] The angular velocity ω1 is fed to multiplier 50d. Multiplier 50d multiplies the angular velocity ω1 by the proportional gain Kp2. The output of multiplier 50d is fed to adder 50c.

[0132] Adder 50c adds the output of multiplier 50a to the output of multiplier 50d. The output of adder 50c is output as the main auxiliary instruction value.

[0133] In this way, the main and auxiliary force calculation unit 50 calculates the main and auxiliary command values ​​based on the tilt angle θ and the angular velocity ω1 of the user's upper body through proportional control.

[0134] In addition, adjust the proportional gains Kp1 and Kp2 appropriately.

[0135] like Figure 7 As shown, the main auxiliary instruction value is given to adder 52.

[0136] In addition, the tilt angle θ is also given to the rotation angle estimation calculation unit 54. The rotation angle estimation calculation unit 54 calculates and estimates the motor rotation angle dφE based on the tilt angle θ. The estimated motor rotation angle dφE is a value that expresses the estimated amount of motion of the motor 33 (actuator 14) based on the tilt angle θ in terms of motor rotation angle.

[0137] Figure 9 This is a block diagram representing an example of the rotation angle estimation calculation unit 54.

[0138] The tilt angle θ given to the estimated rotation angle calculation unit 54 is given to the maximum value holding unit 54a and the adder 54b.

[0139] The maximum value holding unit 54a outputs the maximum value θmax. The maximum value θmax is the maximum tilt angle θ during the operation period (within a specified period). The operation period refers to the continuation period of the on-state after the power supply of the auxiliary device 10 is switched on.

[0140] The maximum value holding unit 54a has the function of holding the maximum value θmax and the function of comparing the held maximum value θmax with the most recently given tilt angle θ and updating the larger tilt angle θ to the maximum value θmax.

[0141] The maximum value θmax output by the maximum value holding unit 54a is given to the adder 54b.

[0142] Adder 54b subtracts the tilt angle θ from the maximum value θmax to obtain the tilt angle difference Δθ. The tilt angle difference Δθ is then given to the arithmetic unit 54c.

[0143] The computation unit 54c calculates the estimated motor rotation angle dφE based on the tilt angle difference Δθ.

[0144] As described above, the amount of action of actuator 14 is correlated with the tilt angle θ. The calculation unit 54c has data representing the correlation between the change in tilt angle θ and the change in the rotation angle φD of the detected motor. Based on this data, the calculation unit 54c converts the tilt angle difference Δθ into a value equivalent to the change in the rotation angle φD of the detected motor, and calculates the estimated motor rotation angle dφE.

[0145] Furthermore, this data only needs to be data that can be used to calculate the value of the change in the rotation angle φD of the detection motor based on the tilt angle difference Δθ. It can be a table obtained through experiments, simulations, or formulas.

[0146] Here, the tilt angle difference Δθ represents the tilt angle of the upper body relative to the maximum value θmax. Therefore, the output of the calculation unit 54c (estimated motor rotation angle dφE) is also calculated as the motion quantity relative to the maximum value θmax.

[0147] The maximum value θmax can be considered the value when the user leans their upper body forward to the maximum extent. Therefore, the tilt angle difference Δθ is the angle difference between the upper body at its maximum forward lean and the current upper body position.

[0148] Therefore, the estimated motor rotation angle dφE represents the angle difference between the motor rotation angle when the upper body is leaning forward to its maximum extent and the estimated value of the current motor rotation angle.

[0149] In this embodiment, the tilt angle difference Δθ represents the angle with the maximum value θmax as a reference. Therefore, a reference can be appropriately set for the tilt angle θ, which is a relative value and changes progressively according to the user's posture.

[0150] As described above, the rotation angle calculation unit 54 estimates the motor rotation angle dφE based on the tilt angle θ.

[0151] like Figure 7 As shown, the estimated motor rotation angle dφE is given to the auxiliary force calculation unit 56.

[0152] In addition, an auxiliary force calculation unit 56 is added to detect the motor rotation angle φD.

[0153] The auxiliary force calculation unit 56 calculates the auxiliary force command value based on the estimated motor rotation angle dφE and the detected motor rotation angle φD.

[0154] Figure 10 This is a block diagram showing an example of an additional auxiliary force calculation unit 56.

[0155] The auxiliary force calculation unit 56 includes: a maximum value holding unit 56a, an adder 56b, a differentiator 56c, a first PI control unit 57, and a second PI control unit 58.

[0156] The maximum value holding unit 56a, the first PI control unit 57, and the differentiator 56c are provided with the detection motor rotation angle φD.

[0157] The maximum value holding unit 56a outputs the maximum value φDmax. The maximum value φDmax is the maximum value (maximum angle position) of the detected motor rotation angle φD during the operation period (within the specified period).

[0158] The maximum value holding unit 56a has the function of holding the maximum value φDmax and comparing the held maximum value φDmax with the most recently given detection motor rotation angle φD and updating the larger value as the maximum value φDmax. In other words, the maximum value holding unit 56a holds the maximum value φDmax (maximum operating position) of the detection motor rotation angle φD when the tilt angle θ is the maximum value θmax.

[0159] The maximum value φDmax output by the maximum value holding unit 56a is given to the adder 56b.

[0160] In addition to the maximum value φDmax, the estimated motor rotation angle dφE is also given to adder 56b. Adder 56b subtracts the estimated motor rotation angle dφE from the maximum value φDmax to obtain the estimated motor rotation angle φE (the estimated operating position of actuator 14).

[0161] As mentioned above, the estimated motor rotation angle dφE represents the angular difference between the estimated motor rotation angle when the upper body is leaning forward at its maximum and the current estimated motor rotation angle. Therefore, if the estimated motor rotation angle dφE is subtracted from the maximum value φDmax, we obtain the position (motor rotation angle) from which the estimated motor rotation angle dφE has moved from the maximum value φDmax.

[0162] In other words, the estimated motor rotation angle φE (estimated operating position of actuator 14) is the motor rotation angle (operating position) that has been moved from the maximum value φDmax (maximum operating position) by the estimated motor rotation angle dφE (estimated value of the operating amount).

[0163] Thus, in this embodiment, the estimated motor rotation angle φE is calculated as the operating position based on the maximum value φDmax.

[0164] The estimated motor rotation angle φE is given to the first PI control unit 57.

[0165] As described above, in addition to estimating the motor rotation angle φE, the detection of the motor rotation angle φD is also given to the first PI control unit 57.

[0166] The first PI control unit 57 includes adders 57a and 57b, multipliers 57c and 57d, and an integrator 57e.

[0167] The estimated motor rotation angle φE and the detected motor rotation angle φD are fed to adder 57a.

[0168] Adder 57a subtracts the detected motor rotation angle φD from the estimated motor rotation angle φE.

[0169] As mentioned above, the estimated motor rotation angle φE is the motor rotation angle that has been shifted from the maximum value φDmax by the estimated motor rotation angle dφE (the estimated value of the motion).

[0170] Therefore, the output of adder 57a represents the difference Δφ (position difference) between the motor rotation angle detected by rotation angle sensor 36 (the operating position of actuator 14) and the estimated value of the motor rotation angle (the estimated operating position of actuator 14).

[0171] The output of adder 57a is fed to multipliers 57c and 57d.

[0172] The output of multiplier 57c is multiplied by the proportional gain Kp3 of adder 57a. The output of multiplier 57c is then fed to adder 57b.

[0173] The output of multiplier 57d is multiplied by the integral gain Ki1 of adder 57a. The output of multiplier 57d is fed to integrator 57e. The output of integrator 57e is fed to adder 57b.

[0174] Adder 57b adds the output of multiplier 57c to the output of integrator 57e. The output of adder 57b is given to the second PI control unit 58. The output of adder 57b is the output of the first PI control unit 57.

[0175] In addition, the proportional gain Kp3 and integral gain Ki1 are adjusted appropriately.

[0176] In addition to the output of the first PI control unit 57, the angular velocity ω2 is also given to the second PI control unit 58. The angular velocity ω2 is obtained by differentiating the rotation angle φD of the detection motor.

[0177] As described above, the rotation angle φD of the detected motor is given to the differentiator 56c. The differentiator 56c differentiates the rotation angle φD of the detected motor and gives the angular velocity ω2 to the second PI control unit 58.

[0178] The second PI control unit 58 includes adders 58a and 58b, multipliers 58c and 58d, and an integrator 58e.

[0179] The output of the first PI control unit 57 and the angular velocity ω2 are given to the adder 58a.

[0180] Adder 58a subtracts angular velocity ω2 from the output of first PI control unit 57.

[0181] The output of adder 58a is fed to multipliers 58c and 58d.

[0182] The output of multiplier 58c is multiplied by the proportional gain Kp4 of adder 58a. The output of multiplier 58c is then fed to adder 58b.

[0183] The output of multiplier 58d is multiplied by the integral gain Ki2 of adder 58a. The output of multiplier 58d is fed to integrator 58e. The output of integrator 58e is fed to adder 58b.

[0184] Adder 58b adds the output of multiplier 58c to the output of integrator 58e and outputs the additional auxiliary force command value.

[0185] In this way, the first PI control unit 57 and the second PI control unit 58 perform proportional-integral control based on the motor rotation angle difference Δφ and the detected motor rotation angle φD to obtain the additional auxiliary force command value.

[0186] In addition, the proportional gain Kp4 and integral gain Ki2 are adjusted appropriately.

[0187] like Figure 7 As shown, the additional auxiliary force command value is given to adder 52.

[0188] Adder 52 adds the auxiliary command value (first command value) and the additional auxiliary force command value (second command value) to obtain the current command value.

[0189] The current command value obtained by the arithmetic processing 40a1 is given to the drive circuit 42 for use in the control of the actuator 14 (motor 33).

[0190] Based on the above structure, the additional auxiliary force command value included in the current command value is calculated based on the difference Δφ (position difference) between the detected motor rotation angle φD (operating position of actuator 14) detected by rotation angle sensor 36 (second sensor) and the estimated motor rotation angle φE (estimated operating position of actuator 14) based on tilt angle θ. The motor rotation angle difference Δφ is a value indicating whether the belt 13 follows the user's posture.

[0191] When the motor rotation angle difference Δφ increases, the control unit 40 of this embodiment controls the increase of the additional auxiliary force command value to reduce the motor rotation angle difference Δφ. This allows the winding force of the actuator to be increased to a level that eliminates hooking, friction, and other issues between the user and the belt. As a result, the deviation between the tilt angle θ and the detection motor rotation angle φD can be suppressed, and the decrease in the following performance of the belt 13 can be suppressed.

[0192] [Verification Experiment]

[0193] Figure 11A as well as Figure 11B This is a diagram showing the results of the verification test of the auxiliary device 10 in the above-described embodiments.

[0194] Figure 11A This is a graph showing the relationship between the tilt angle and the motor current of motor 33.

[0195] exist Figure 11A In the graph, the horizontal axis represents time, and the vertical axis represents the tilt angle and motor current. Furthermore, Figure 11A The tilt angle represents the angle when the user's upper body is in a vertical position, which is set to 0°.

[0196] exist Figure 11AIn the graph, line graph L1 represents the change of the tilt angle over time. Line graph L1 shows the tilt angle decreasing from approximately 90° over time. In other words, in... Figure 11A The image shows the process of the user's upper body changing posture from an almost horizontal position to an upright position.

[0197] exist Figure 11A In the diagram, line graph L2 shows the current flowing through motor 33. Line graph L21 shows the current flowing through motor 33 when controlled solely by main and auxiliary command values. As the tilt angle decreases, line graph L21 gradually decreases over time.

[0198] exist Figure 11A In the diagram, the difference between line diagram L2 and line diagram L21 is the current added by the auxiliary force command value. Furthermore, the current value added by the auxiliary force command value is approximately 20% of the current value based solely on the main auxiliary command value.

[0199] Therefore, when the user's posture changes from a forward-leaning posture to an upright posture, the control unit 40 controls the additional auxiliary force command value to temporarily increase the overall current value flowing through the motor 33.

[0200] Figure 11B This is a graph showing the relationship between the tilt angle and the motor rotation angle of motor 33.

[0201] exist Figure 11B In the diagram, the horizontal axis represents time, and the vertical axis represents the tilt angle and motor rotation angle. Furthermore, Figure 11B Time and tilt angle Figure 11A The time and tilt angle correspond.

[0202] Figure 11B Line graph L3 in the diagram shows the change of the tilt angle over time. Therefore, Figure 11A Line chart L1 and Figure 11B The line graph L3 in the text is the same line graph.

[0203] exist Figure 11B In the diagram, line graph L4 shows the change of the motor rotation angle of motor 33 over time. If line graph L3 is compared with line graph L4, there is no significant difference between the change of tilt angle over time and the change of motor rotation angle over time.

[0204] Figure 12 This is a graph showing the relationship between the tilt angle and the motor rotation angle of motor 33 when controlled solely by the main and auxiliary command values.

[0205] exist Figure 12 In the diagram, line graph L5 shows the change of the tilt angle over time. Line graph L6 shows the change of the motor rotation angle of motor 33 over time.

[0206] like Figure 12 As shown, when controlled solely by the main and auxiliary command values, a divergence occurs between the tilt angle and the motor rotation angle. This indicates that when the user changes posture from a forward-leaning position to an upright position, the belt 13 does not follow the posture change.

[0207] In contrast, in this embodiment, such as Figure 11B As shown, there is no significant difference between the change in tilt angle over time and the change in motor rotation angle over time, and the belt 13 follows the change in posture.

[0208] The results show that, according to this embodiment, when the user's posture changes, the control unit 40 increases the additional auxiliary force command value to increase the winding force of the actuator 14, which can suppress the decrease in the following performance of the belt 13.

[0209] 〔other〕

[0210] The implementation methods disclosed herein are illustrative and not restrictive in all respects.

[0211] For example, in the above embodiment, the operating position of the actuator 14 is shown as the motor rotation angle of the motor 33. However, the operating position of the actuator 14 can be, for example, the position of the belt 13 relative to a reference position provided in the control box 30, etc. In this case, instead of the rotation angle sensor 36, a sensor that detects the position of the belt 13 is used.

[0212] Furthermore, in the above embodiments, the description mainly focuses on the situation where the user's posture changes from a forward-leaning posture to an upright posture, but the same effect is also achieved when the posture changes from an upright posture to a forward-leaning posture.

[0213] For example, increasing the motor current when changing from an upright to a leaning posture can sometimes hinder the user's movement. Therefore, the motor current is increased according to the user's movement. More specifically, the speed of the user's movement (tilt angle) is detected, and the motor current is increased when it is determined that the speed of the user's movement is close to zero and the user wants to stop moving (to maintain the posture). In this way, the user's movement is detected, and the motor current value is increased or decreased so as not to hinder their movement. A well-tracking assist force is applied through this increase or decrease.

[0214] The scope of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope equivalent to the structure described in the technical solution.

[0215] Explanation of reference numerals in the attached figures

[0216] 10…Auxiliary device; 11…First wearable piece; 12…Second wearable piece; 13…Belt body; 14…Actuator; 33…Motor; 35…Drive pulley; 36…Rotation angle sensor (second sensor); 38…Inertial sensor (first sensor); 40…Control unit; BL…Legs; UB…Upper body.

Claims

1. An assistive device comprising: a first wearing member to be worn on an upper body of a user; a second wearing member to be worn on left and right leg portions of the user; a belt to be disposed across the first wearing member and the second wearing member and along a back of the user; an actuator provided to the first wearing member, capable of performing a winding action and a feeding action on a portion of the belt, and causing an assistive force to act on the user by applying a winding force corresponding to a command value to the belt; a first sensor to detect an inclination angle of the upper body; a second sensor to detect a position of the actuator; and a control unit to calculate the command value, the command value being a value obtained by adding a first command value to a second command value, the control unit performing: a process to calculate the first command value based on the inclination angle of the upper body; a process to calculate an estimated value of an action amount of the actuator based on the inclination angle of the upper body; and a process to calculate the second command value based on a position difference between the position of the actuator detected by the second sensor and an estimated position of the actuator based on the estimated value of the action amount.

2. The assistive device according to claim 1, wherein the process to calculate the estimated value of the action amount includes: a process to hold a maximum value of the inclination angle within a prescribed period; a process to calculate an inclination angle difference between the maximum value of the inclination angle and a current inclination angle of the inclination angle; and a process to calculate the estimated value of the action amount based on the inclination angle difference.

3. The assistive device according to claim 2, wherein the estimated position of the actuator is a position obtained by moving the maximum position of the actuator at which the inclination angle is the maximum value from the position of the actuator by the estimated value of the action amount.

4. The assistive device according to claim 1, wherein the second command value is calculated by proportional integral control based on the action amount difference.

5. The assistive device according to any one of claims 1 to 4, wherein the actuator includes: a pulley to wind the portion of the belt; and a motor to drive the pulley, the position of the actuator being a rotation angle of the motor. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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