JP7492293B1 - Wearable Assistive Robot Device - Google Patents

Abstract

[Problem] To provide a wearable assist robot device that reliably and quickly assists the wearer in the lifting and squatting postures. [Solution] An assist drive mechanism 50 having a reel 52 is fixed to a back member 21 of a trunk holder 20. One end 40a below a belt 40 is connected to a thigh holder 30 worn on the left and right thighs 7. The other end 40b above the belt 40 is fixed to the reel 52 and is wound and pulled by the power of a drive source 54, generating an assist force to assist the muscle power. The thigh holders 30 are worn on the left and right thighs 7, covering the femoral triangle 8, respectively, and do not slip above the thighs 7, ensuring reliable muscle power assistance. As the belt 40 is pulled by the reel 52, the muscle power assistance action is quicker than with a screw drive or the like. [Selected Figure] Figure 1

Description

The present invention relates to a wearable assistive robot device, also known as a power assist suit or power assist robot device, which assists the wearer in performing physical labor and other tasks.

In this specification, the terms "left and right," "front and back," "up and down," "front," "side," "plane," "back," and "back" refer to the directions of the wearer being supported when standing upright with both legs aligned along with the trunk, also known as the upper body.

Hatching and diagonal lines in drawings may be used even on parts that are not cross-sectional views to clearly show the structure.

In a conventional wearable assistive robot device (Patent Document 1), which is a muscle-assisting device for lifting assistance, the back pad has an upper pad, a lower pad, and an elastic pad connecting them. The upper pad and the lower pad are made of a material that is highly flexible and has very little elasticity. The elastic pad is made of a material that is highly flexible and elastic. The upper pad has a pair of shoulder supports that are fixed to the shoulders. A pair of hip joint supports, each made of a band member that encircles each of the left and right thighs, are fixed to the left and right at a distance. The actuator expands and contracts the distance between its upper and lower ends by the screw drive of a motor, one end of which is fixed to the upper pad via an upper wire, and the other end of which is fixed to the lower pad via a lower wire. The expansion and contraction drive of the actuator changes the distance between the upper pad and the lower pad, expanding and contracting the distance from the wearer's shoulders around the back to the hip joints, providing muscle assistance for movements involving forward bending. The actuator is arranged along the lower pad.

In this conventional wearable assistive robot device, the left and right hip joint supports are fixed to lower pads that have very little elasticity, so the hip joint supports cannot be held in appropriate left and right positions corresponding to the size of the wearer's trunk and thighs. As a result, when the actuator contracts to pull up the lower pad, and therefore the hip joint supports, via the lower wire, the holding position of the hip joint supports on the thighs shifts upward. This makes it difficult to reliably provide muscle assistance for movements involving forward bending.

In addition, because the actuator expands and contracts using the screw drive of the motor, it is not possible to provide rapid muscle assistance in response to the wearer's bending forward posture.

JP2005-339

The objective of the present invention is to provide a wearable assistive robot device that can reliably and quickly provide muscle support in response to the wearer's forward bending posture.

The present invention relates to
(a) a trunk support 20 (FIG. 1), 120 (FIG. 15) having a back member 21 arranged behind the trunk 5 of the wearer 4 and held by the trunk 5;
(b) a pair of thigh holders 30 to be attached to the left and right thighs 7 of the wearer 4 so as to cover the femoral triangles 8,
(c) a belt 40 that extends vertically along the back of the trunk 5 and has a lower end 40a connected to the pair of thigh holders 30;
(d) an assist drive mechanism 50 provided on the rear member 21,
(d1) a winding drum 52 to which the other upper end 40b of the belt 40 is fixed and which winds up the belt 40;
(d2) a drive source 54,
(d2-1) a motor 55 that drives the winding drum 52;
(d2-2) A drive source 54 having a motor angle detector 57 for detecting a motor angle θm at which the output shaft 56 of the motor 55 rotates;
(d3) a control unit 60 that pulls the belt 40 by the driving source 54 to give the wearer 4 an assist force for lifting the load acting on the hand 9 of the wearer 4 in a lifting posture,
(d3-1) A motion sensor 61 provided on the back member 21 for detecting the acceleration α or angular velocity ω of the trunk 5;
(d3-2) A processing circuit 65,
(d3-2-1) a forward bending angle detection unit 66 that determines a forward bending angle θs of the trunk 5 by integrating the acceleration α or the angular velocity ω in response to an output of the motion sensor 61;
(d3-2-2) a posture detection unit 67 that detects a lifting posture based on a forward bending angle θs in response to an output of the forward bending angle detection unit 66;
(d3-2-3) an assist force setting unit 68 that is responsive to an output of the posture detection unit 67 and that generates an assist force to be applied to the wearer 4 for the lifting posture by the drive source 54 when the lifting posture is detected;
(d3-2-4) A wearable assistive robot device including an assist drive mechanism 50 having a control unit 60 equipped with a processing circuit 65 having a forward bending angle correction unit 71 that responds to the output of a motor angle detector 57 and corrects the forward bending angle θs of a forward bending angle detection unit 66 based on the motor angle θm.

According to the present invention, the wearer 4 wears the trunk holder 20 of the wearable assistive robot device 1 and wears a pair of left and right thigh holders 30 on the thighs 7. To be held by the trunk 5, the trunk holder 20 may have a pair of left and right shoulder belts 22 (Fig. 1) that respectively cover the left and right shoulders of the wearer 4, but may also have, for example, a long, thin, flat, belt-like waist support 103 (Fig. 15) that is placed above the waist 11 and surrounds the waist 11 in a ring shape, or may have another configuration that holds a load acting downward on the trunk 5.

When the torso holder 20 is worn, the belt 40 extends vertically along the back of the torso 5, and therefore behind the back member 21. The lower end 40a of the belt 40 is connected to the thigh holder 30. The upper end 40b of the belt 40 is fixed to a reeling drum 52 in an assist drive mechanism 50 provided on the back member 21. The reeling drum 52 reels the belt 40 by the power of a motor 55 of a drive source 54. The control unit 60 pulls the belt 40 by the drive source 54 to provide the wearer 4 with an assist force for lifting a load acting on the hands 9, etc., in a lifting posture, and an assist force for supporting the mass of the upper body to maintain a half-squat posture in a half-squat posture. The motor 55 may be, for example, a torque motor.

The pair of thigh holders 30 are attached to the thighs 7, covering the left and right femoral triangles 8, respectively. Therefore, one end 40a of the belt 40 is connected to each thigh holder 30, and when the belt 40 is wound around the spool 52 and pulled up to exert an assisting force, the thigh holders 30 do not shift upward in their holding position on the thighs. Therefore, the assisting force in the lifting and squatting positions can reliably assist the muscles in movements involving forward bending.

In addition, the belt 40 is wound around the drum 52 and pulled, rather than being stretched and contracted by a screw drive of a motor as in the prior art described above. Therefore, it is possible to provide rapid muscle assistance in response to the forward bending posture of the wearer 4.

According to the present invention, the motion sensor 61 provided on the back member 21 detects the acceleration α or angular velocity ω of the trunk 5, and the forward bending angle detection unit 66 integrates this acceleration α or angular velocity ω to calculate and obtain the forward bending angle θs of the trunk 5. The forward bending angle θs is the angle of forward bending of the trunk 5 about the left and right axes passing through the hip joints or buttocks when the wearer 4 is in a forward bending posture with the waist bent (crouched) and the lower limbs including the thighs 7 are upright and the spine is straightened, and this can also be called the posture angle.

The posture detection unit 67 detects the lifting posture based on the forward bending angle θs. The assist force setting unit 68 generates an assist force, which is a pulling force applied to the wearer 4 for the lifting posture , by the drive source 54, i.e., the motor 55 driving the reel 52 to reel the belt 40 onto the reel 52 and pull it.

The output of the motor 55 can be set by the assist force setting unit 68 so that the assist force for the lifting posture is, for example, a lifting force equivalent to strong 10 kgf, medium 8 kgf, or weak 6 kgf. If the motor 55 is a torque motor, the output torque can be set by the drive voltage.

According to the present invention, the forward bending angle detection unit 66 determines the forward bending angle θs by integrating the acceleration α or angular velocity ω of the trunk 5 detected by the motion sensor 61. Therefore, when the integration is continued, noise is added, causing a so-called drift error, and the calculated value of the forward bending angle θs gradually deviates from the actual correct angle.

To solve this problem, the present invention provides a forward bending angle correction unit 71. The forward bending angle correction unit 71 corrects the calculated value of the forward bending angle θs by the forward bending angle detection unit 66 so that no error occurs or so that the error is reduced. The forward bending angle correction unit 71 uses the output from the motor angle detector 57 as the initial angle (or angle at a certain point in time, boundary condition) for each repeated calculation at a predetermined time interval during integration. It is important that the output from the motor angle detector 57 does not include drift errors. The motor angle detector 57 detects the motor angle θm, which is the rotation angle of the output shaft 56 of the motor 55, as it is, so the detected value does not deviate from the actual correct angle of the output shaft 56.

The present invention relates to
The driving source 54 further includes:
a torque limiter 80 that transmits the power of the output shaft 56 of the motor 55 to the winding drum 52, and when an excessive tensile force equal to or greater than a predetermined value acts on the belt 40 in the other direction, that is, in the driving of the motor 55 in one direction to wind up the belt 40 of the winding drum 52, the torque limiter 80 causes the winding drum 52 to slip in rotation in the other direction relative to the output shaft 56;
The processing circuitry 65 further
A slippage occurrence detection unit 72 that detects the occurrence of slippage of the torque limiter 80;
a slip angle calculation unit 73 that determines a slip angle δ at which the winding drum 52 slips relative to the output shaft 56 of the motor 55 in response to an output of the slip occurrence detection unit 72;
and a motor angle correction unit 74 which, in response to the output of the slip angle calculation unit 73, corrects the motor angle θm1 immediately before the occurrence of the slip based on the slip angle δ when the occurrence of the slip is detected, and provides this corrected motor angle θm2 to the forward bending angle correction unit 71 for correcting the forward bending angle θs.

The motor angle θm corresponds to the rotation angle of the winding drum 52, and therefore the belt length L of the belt 40, in the following cases (a) and (b). (a) A configuration in which a torque limiter 80 for protecting the motor 55 is not interposed between the output shaft 56 of the motor 55 and the winding drum 52, and (b) A state in which the torque limiter 80 is provided but no slippage occurs between the output shaft 56 and the winding drum 52. In each of these cases (a) and (b), the motor angle θm, which is the output of the motor angle detector 57, corresponds to the rotation angle of the winding drum 52 and corresponds to the belt length L (i.e., the length between one end 40a of the belt 40 connected to the thigh holder 30 and the winding drum 52 on which the other end 40b is wound). This belt length L corresponds to the forward bending angle θs of the wearer 4, regardless of the presence or absence of the torque limiter 80, and becomes longer as the wearer 4 bends deeply and the forward bending angle θs becomes larger. The forward bending angle correction unit 71 corrects the forward bending angle θs from the forward bending angle detection unit 66 based on the motor angle θm in each of the cases (a) and (b) described above, eliminating errors such as drift errors contained in the forward bending angle θs.

Assuming another case (c), a torque limiter 80 is provided and slippage occurs between the output shaft 56 and the winding drum 52. In this case (c), the output shaft 56 does not undergo angular displacement before and after the occurrence of the slippage, so the output of the motor angle detector 57 immediately after the slippage remains the motor angle θm1 corresponding to the belt length L1 immediately before the slippage, and is not the motor angle θm2 corresponding to the belt length L2 immediately after the slippage. Therefore, the output of the motor angle detector 57 is corrected to the motor angle θm2 corresponding to the belt length L2 immediately after the slippage based on the forward bending angles θs1 and θs2 before and after the occurrence of the slippage by the motor angle correction unit 74 of the processing circuit 65 described next. After that, the forward bending angle θs is corrected based on the corrected output θm of the motor angle detector 57 as a reference, and errors such as drift errors contained in the forward bending angle θs are eliminated.

According to the present invention, in the state where the motor 55 drives the reel drum 52 via the torque limiter 80 in one direction to reel the belt 40 and provide the wearer 4 with an assist force, in the above-mentioned case (c), for example, when the wearer 4 suddenly assumes a bent-over posture, the forward bending angle θs obtained by the forward bending angle detection unit 66 suddenly changes to a large value. At this time, an excessive pulling force acts on the belt 40. This excessive pulling force is a value that exceeds the assist force for the lifting posture and the half-squat posture, and is a predetermined value in the other direction to reel out and unwind the belt 40 of the reel drum 52, for example, a pulling force of 15 kgf or more. As a result, the reel drum 52 generates a rotational slip in the other direction by the slip angle δ with respect to the output shaft 56, and the motor 55 is protected.

The present invention relates to
The slip occurrence detection unit 72 is
The forward bending angle θs is constantly monitored in response to the output of the forward bending angle detection unit 66, and when the forward bending angle θs changes significantly and suddenly within a predetermined short period of time ΔW, the change amount Δθs (=θs2-θs1) of each of the values θs1 and θs2 before and after the forward bending angle θs becomes equal to or larger than a predetermined value Δθs0, the occurrence of slippage is detected.

The slippage detection unit 72 detects the occurrence of slippage in the torque limiter 80 .
According to the present invention, the slip occurrence detection unit 72 detects that the forward bending angle θs obtained by the forward bending angle detection unit 66 has suddenly changed significantly within a predetermined short time ΔW, thereby detecting the occurrence of slip of the torque limiter 80. For example, when the amount of change Δθs (=θs2-θs1) of the values θs1 and θs2 before and after the forward bending angle θs that has suddenly changed significantly within a predetermined short time ΔW becomes equal to or larger than a predetermined value Δθs0 (Δθs0≦Δθs), the occurrence of slip is detected.

In this way, when the wearer 4 suddenly assumes a bent forward-leaning posture, the torque limiter 80 slips, but the motor angle θm detected by the motor angle detector 57 of the output shaft 56 of the motor 55 does not change and remains constant before and after the slip. The reel 52 rotates by the slip angle δ relative to the output shaft 56 to unwind and unwind the belt 40. At that time, the forward-leaning angle θs obtained by integrating the acceleration α or angular velocity ω of the trunk 5 detected by the motion sensor 61 increases rapidly from the value θs1 before the sudden change to θs2 after the sudden change, corresponding to the sudden bent forward-leaning posture. Therefore, it can be inferred that the torque limiter 80 has caused a slip phenomenon by detecting the sudden increase in the forward-leaning angle θs.

The present invention relates to
The slip occurrence detection unit 72 is
In response to the outputs of the forward bending angle detection unit 66 and the motor angle detector 57, a difference Δθsm between the forward bending angle θs detected by the forward bending angle detection unit 66 and the motor angle θm detected by the motor angle detector 57 is constantly monitored;
When the difference Δθsm suddenly changes, the occurrence of slippage is detected.

According to the present invention, the difference Δθsm (= θs - θm) between the forward bending angle θs and the motor angle θm is constantly monitored, and immediately after the occurrence of a slip, the difference Δθsm (= θs2 - θm1) suddenly changes and becomes large, and at this point, the occurrence of a slip is detected.

The present invention relates to
The slip angle calculation unit 73 calculates
The device is characterized in that it has a memory for storing a correspondence relationship between the slip angle δ and the amount of change Δθs (=θs2-θs1) in the forward bending angles θs1 and θs2 before and after a sudden change in the forward bending angle θs, and calculates and determines the slip angle δ from the amount of change Δθs.

The slip angle δ of the motor angle θm corresponds to the amount of change Δθs (= θs2 - θs1) between the forward bending angles θs1 and θs2 before and after the sudden change in the forward bending angle θs. Therefore, in the slip angle calculation unit 73, for example, the correspondence between the slip angle δ and the amount of change Δθs is prepared and stored in advance in memory, and the slip angle δ is calculated from the amount of change Δθs based on that correspondence.

The present invention relates to
The slip angle calculation unit 73 calculates
The slip angle δ is calculated by determining that the belt length L (Equation 1, FIGS. 12 to 14) of the belt 40 unwound from the winding drum 52 of radius R by rotation at the motor angle θm1 and slip angle δ just before the occurrence of slippage is equal to the total length LA (Equation 5) of the five lumbar vertebrae LB1 to LB5 at the forward bending angle θs2 just after the occurrence of slippage.

In another embodiment, the slip angle calculation unit 73 calculates the slip angle δ according to equations (1) to (5) with reference to Figures 12 to 14 described below.

The present invention relates to
The posture detection unit 67 further detects a half-squatting posture when the forward bending angle θs continues for a predetermined time W1 or more.
The wearable assistive robot device according to claim 1, further characterized in that the assist force setting unit 68 responds to the output of the posture detection unit 67, and when a squatting posture is detected, generates an assist force to be applied to the wearer 4 for the squatting posture by the drive source 54.

The posture detection unit 67 detects the squatting posture when the forward bending angle θs continues for a predetermined time W1 (e.g., 3 seconds) or more. The assist force setting unit 68 generates an assist force, which is a pulling force applied to the wearer 4 for the squatting posture, by the drive source 54, and therefore the motor 55, driving the hoisting drum 52 to wind and pull the belt 40 around the hoisting drum 52.

The assist force setting unit 68 can set the output of the motor 55 so that the assist force for the crouching position is, for example, 60% of the assist force for the lifting position .

The present invention relates to
The processing circuit 65 further has an assist force stopping unit 69, which responds to the output of the forward bending angle detection unit 66 and stops the generation of the assist force by the drive source 54 of the assist force setting unit 68 when the forward bending angle θs becomes a predetermined initial setting value, and is characterized in that, in a state in which the generation of the assist force is stopped, the output torque of the motor 55 is set so that the belt 40 is wound up by the winding drum 52 with a winding force that eliminates slack in the belt 40.

According to the present invention, the processing circuit 65 further includes an assist force stop unit 69. This assist force stop unit 69 responds to the output of the forward bending angle detection unit 66, and when the forward bending angle θs becomes a predetermined initial setting value, for example, when the forward bending angle θs becomes a predetermined value in a forward bending state of less than 10°, in which the wearer 4 is in an upright state or a forward bending angle θs approximating the upright state becomes, for example, a predetermined value in the forward bending state of less than 10°, stops the generation of the assist force by the drive source 54 of the assist force setting unit 68. In this way, the forward bending angle θs read by the motion sensor 61 after the belt 40 is wound on the winding drum 52 may be initially set and stored in memory, and may be used as the forward bending angle at which lifting or half-sitting muscle assistance ends. Furthermore, in order to eliminate slack in the belt 40 while the generation of such an assist force is stopped, the output torque of the motor 55 is set so that the belt 40 is wound up with a winding force, for example, 0.5 to 1.0 kgf. Alternatively, instead of the initially set forward bending angle θs, the motor angle θm0 of the motor 55 after the belt 40 is wound around the winding drum 52 may be initially set and stored in memory as the motor angle at which muscle assistance for lifting or squatting ends.

The present invention relates to
The belt 40 is made of a single piece, and one end 40a of the belt 40 is connected to the pair of thigh holders 30.
The trunk support 120 (FIG. 15) has a waist support 103 provided on a back member 121, and this waist support 103 is placed on the upper part of the hip bone in the pelvis of the waist 11 to surround the waist 11, and is characterized in that it receives a downward load at the waist 11.

According to the present invention, the pair of thigh holders 30 are arranged very close to each other, since they cover the left and right femoral triangles 8, respectively. Therefore, one end 40a of a single belt 40 can be commonly connected to each thigh holder 30. This simplifies the configuration, as there is no need to provide a belt for each thigh holder 30.

According to the present invention, the lumbar support 103 shown in Fig. 15 is disposed on the upper part of the waist 11, and is therefore capable of receiving a downward load from the waist 11. The upper part of the waist 11 is the upper part of the hip bone in the pelvis. The lumbar support 103 may be configured, for example, in the shape of a flattened belt having at least a portion that surrounds the circumference of the trunk 5 in a circular shape.

The lifting assist force and squatting posture maintaining assist force act in relation to the upper part of the pelvis by the waist support 103, and therefore the lower limbs including the thighs 7. In the present invention, they do not act by pulling up the upper body, which is the trunk 5, through the shoulder belts 122. Therefore, the assist force by the pulling of the belts 40 acts on the wearer 4 so as to raise the upper body without causing the trunk 5 to bend concavely toward the back and arching backwards. As a result, the assist force is smoothly transmitted to the upper body, which is the trunk 5, so the wearer is less likely to get tired.
The torso support 120 may have a pair of left and right shoulder belts 122 that respectively cover the left and right shoulders of the wearer 4, but these may be omitted.

FIG. 1 is a rear view of a wearable assistive robot device 1 according to an embodiment of the present invention, as viewed from behind in a state in which the wearer 4 wears the device. FIG. 2 is a front view showing the wearable assistive robot device 1 in a worn state. FIG. 2 is a side view showing the wearable assistive robot device 1 in a worn state. 5 is a front view seen from the rear showing the winding drum 52, the driving source 54, the control unit 60, and the secondary battery 78 mounted on the base 58 of the assist drive mechanism 50. FIG. FIG. 5 is a side view of the assist drive mechanism 50 shown in FIG. 4 . 4 is a cross-sectional view showing the winding drum 52 and the torque limiter 80. FIG. 2 is an exploded perspective view showing the winding drum 52 and the torque limiter 80. FIG. FIG. 11 is a simplified side view for explaining the forward bending angle θs of the wearer 4. FIG. 2 is an electric circuit diagram showing the electrical configuration of the support robot device 1. 13 is a flowchart showing the procedure of an assist suit control process executed by the processing circuit 65 of the wearable assist robot device 1. 11 is a flowchart showing specific operations related to the occurrence of slippage and the correction of the forward bending angle θs in step s9 of FIG. 10, which are executed by the processing circuit 65. This is a side view of the lumbar vertebrae LB1 to LB5 of the spine and their surrounding areas when the wearer 4 is in an upright position, as viewed from the left lateral side. 1 is a simplified left side view showing a state in which the wearer 4 is in a forward bending position with five lumbar vertebrae LB1 to LB5 bent. 1 is a simplified left side view showing a state in which the wearer 4 is in an upright position and the five lumbar vertebrae LB1 to LB5 are not bent. FIG. 11 is a rear view of a wearable assistive robot device 101 according to another embodiment of the present invention, seen from behind in a state in which the wearer 4 wears the device.

1 is a rear view of a wearable assistive robot device 1 according to an embodiment of the present invention, seen from behind when worn by a wearer 4, FIG. 2 is a front view showing the wearable assistive robot device 1 being worn, and FIG. 3 is a side view showing the wearable assistive robot device 1 being worn. The wearable assistive robot device 1 is configured to be substantially symmetrical on the left and right sides with respect to the midsagittal plane of the wearer 4 wearing it, and in this specification and drawings, the reference numbers for the left and right components are generally indicated by numbers alone, with the suffixes L and R added to the numbers to indicate the left and right individually. With reference to these drawings, the wearable assistive robot device 1 comprises a trunk holder 20 held on the trunk 5 of the wearer 4, a pair of thigh holders 30 worn on the left and right thighs 7 of the wearer 4, a single belt 40 extending vertically along the back of the trunk 5, and an assist drive mechanism 50 that drives the belt 40 to provide the wearer 4 with an assist force for lifting and an assist force for maintaining a half-squat posture. The trunk holder 20 has a back member 21 arranged behind the trunk 5. To the back member 21, shoulder belts 22 are attached that cover the left and right shoulders of the wearer 4. The back member 21 extends from the upper part of the scapular region to the vicinity of the lower part of the scapular region, and is formed in a relatively small size. The thigh holder 30 is worn by covering the left and right femoral triangles 8, respectively, with both ends of a pair of holding belts 31 that surround the thighs 7 in a ring shape being detachably connected by a connecting member 32. The holding belts 31 of the thigh holder 30 are connected to one end 40a below the belt 40 by each connecting piece 41 that is close to the inner side of the trunk 5. The left and right holding belts 31 are arranged very close to each other, covering the femoral triangle 8, respectively, and can be connected individually to each relatively short connecting piece 41, so that the holding belts 31 can be held in appropriate left and right positions corresponding to the size of the trunk 5 and thighs 7 of the wearer 4. Therefore, when the belt 40 is used to pull up the holding belt 31, the holding position of each thigh holder 30 on the thigh 7 does not shift upward. Therefore, muscle assistance for movements involving forward bending is reliable. The belt 40 is flat, flexible, and does not stretch.

The assist drive mechanism 50 has a reel 52 that reels the belt 40, a drive source 54 that drives the reel 52, and a control unit 60 for the drive source 54, and is provided on a base 58 fixed to the back member 21. The other upper end 40b of the belt 40 is fixed to the reel 52, and the belt 40 is wound around the reel 52 and taken up. The control unit 60 pulls the belt 40 with the drive source 54 to provide the wearer 4 with an assist force for lifting the load acting on the wearer's hands 9 in a lifting posture, and an assist force for supporting the mass of the upper body to maintain a half-squat posture in a half-squat posture. A secondary battery 78 that supplies power to the drive source 54 and the control unit 60 is provided on the base 58.

Figure 4 is a front view from the rear showing the reel 52, drive source 54, control unit 60, and secondary battery 78 mounted on the base 58 of the assist drive mechanism 50, and Figure 5 is a side view of the assist drive mechanism 50 shown in Figure 4. The belt 40 is shown in phantom lines in Figures 4 and 5. The drive source 54 has a motor 55, a motor angle detector 57 that detects the motor angle θm, and a torque limiter 80.

As shown by arrow 43 in FIG. 5, the belt 40 is wound from the upper rear (left side in FIG. 5) to the front (right side in FIG. 5) on the straight cylindrical winding surface of the winding drum 52. This allows the moving belt 40 to be spaced apart from the backing member 21, the base 58, clothing on the torso 5, etc., and prevents unwanted rubbing. A cover 59 is provided on the base 58 so as to be able to be opened and closed.

Figure 6 is a cross-sectional view showing the winding drum 52 and the torque limiter 80, and Figure 7 is an exploded perspective view showing the winding drum 52 and the torque limiter 80. The motor 55 of the drive source 54 is fixed to the base 58. Both end plates 44, 45 fixed to the winding drum 52 regulate the displacement of the belt 40 in the width direction being wound. One end plate 44 is supported by the output shaft 56 via a bush 46. The other end plate 45 is attached with a drive plate 81 that acts as a center member of the torque limiter 80, and this drive plate 81 is supported by a hollow shaft 83 of a hub member 82 via a bush 47. The end plate 45 and the drive plate 81 are prevented from angularly displacing each other in the circumferential direction by fitting together protrusions and recesses formed repeatedly in the circumferential direction.

One friction plate 85 is interposed between one end face of the drive plate 81 and the hub plate 84 of the hub member 82. The other friction plate 86 is pressed against the other end face of the drive plate 81 by the elastic force of a spring 88 such as a disc spring via a pressure plate 87. The hollow shaft 83 passes through the friction plates 85 and 86 and rotates integrally with the output shaft 56 by a sinking key 89. The hollow shaft 83 and the pressure plate 87 are prevented from angular displacement relative to each other by a configuration such as a so-called D-cut.

The spring 88 is pressed between the hub plate 84 and the drive plate 81 by an adjustment nut 92 that screws onto an external thread engraved on the hollow shaft 83, via a rotation stopper washer 91. Therefore, the frictional force between the drive plate 81 and the friction plates 85, 86 that are pressed against both end faces of the drive plate 81 is adjusted and set. When an excessive tensile force of a predetermined value or more acts on the belt 40 in the other direction, that is, when the motor 55 drives the belt 40 of the winding drum 52 in one direction 43 (Figure 5) to wind the belt 40 of the winding drum 52, the torque limiter 80 causes the winding drum 52 to rotate in the other direction relative to the output shaft 56. This frictional force corresponds to the tensile force that causes the torque limiter 80 to slip.

The free end of the output shaft 56 is supported on the base 58 by a support 107 via a bearing 106. The bearing 106 and the hub member 82 are prevented from displacing in the direction of the free end of the output shaft 56 by an E-ring 108.

8 is a simplified side view for explaining the forward bending angle θs of the wearer 4. As shown in FIG. 8(1), when the wearer 4 is in an upright position, for example, with a load acting on the hand 9 while holding a baggage 14, the forward bending angle θs from the vertical line 16 in the center to the front (to the right in FIG. 8(1) and (2)) is zero. When the forward bending angle θs is in the upright position of the wearer 4, or the forward bending angle θs approximating the upright position is, for example, a predetermined value in a forward bending state of less than 10°, the generation of the assist force by the drive source 54 is stopped, the muscle assistance for lifting or squatting is ended, and in the state in which the generation of such assist force is stopped, the output torque of the motor 55 is set so that the belt 40 is wound up with a small winding force to eliminate slack in the belt 40. FIG. 8(2) shows the lifting posture and the squatting posture of the load acting on the hand 9 of the wearer 4 at the forward bending angle θs from the vertical line 16 in the center to the front (to the right in FIG. 8(2)). In the state shown in FIG. 8 (2), the assist drive mechanism 50 pulls the belt 40 to provide the wearer 4 with a lifting assist force in the lifting position and an assist force to support the mass of the upper body in order to maintain the squatting position in the squatting position.

Figure 9 is an electrical circuit diagram showing the electrical configuration of the support robot device 1. The assist drive mechanism 50 included in the support robot device 1 basically includes a drive source 54, a control unit 60, and a secondary battery 78. The control unit 60 includes a motion sensor 61, a processing circuit 65 realized by a microcomputer or the like, an operation unit 76, an object sensor 77 of the glove device 94, and the like.

The object sensor 77 detects the presence or absence of a load acting on the palm side of the fingers of the glove worn by the wearer 4, and also the value of that load. The glove device 94 includes a wireless communication unit 95 and a secondary battery 96. The secondary battery 96 supplies power to the object sensor 77 and the wireless communication unit 95. The wireless communication unit 95 sends the state of the object sensor 77, i.e., the detection results detected by the object sensor 77, to the wireless communication unit 97 of the processing circuit 65 via the wireless communication unit 95.

The motion sensor 61 may be a so-called six-axis sensor, having an acceleration sensor 62 that detects the three-dimensional acceleration α of the trunk 5 (i.e., individually, the acceleration α1 in the vertical direction, the acceleration α2 in the front-back direction, and the acceleration α3 in the left-right direction) and an angular velocity sensor 63 that detects the three-dimensional angular velocity ω of the trunk 5 (i.e., individually, the angular velocity ω1 around the vertical axis, the angular velocity ω2 around the front-back axis, and the angular velocity ω3 around the left-right axis). The processing circuit 65 calculates the velocity, position, etc. by integrating the acceleration α in the three axial directions of up-down, left-right, and front-back, and calculates the angle θs by integrating the angular velocity ω around the three axial directions of up-down, left-right, and front-back. For example, the acceleration α1 in the vertical direction of the trunk 5 of the wearer 4 is detected, and the angular velocity ω3 around the left-right axis of the trunk 5 is detected to detect the forward bending angle θs of the trunk 5 around the left-right axis.

The processing circuit 65 has a forward bending angle detection unit 66 that responds to the output of the motion sensor 61 and calculates the forward bending angle θs of the trunk 5, a posture detection unit 67 that responds to the output of the forward bending angle detection unit 66 and detects a lifting posture based on the forward bending angle θs and detects a half-squatting posture when the forward bending angle θs continues for a predetermined time W1 or more, and an assist force setting unit 68 that responds to the output of the posture detection unit 67 and generates an assist force to be applied to the wearer 4 for the lifting posture or half-squatting posture by the drive source 54 when the lifting posture or half-squatting posture is detected. The processing circuit 65 further has an assist force stopping unit 69, which responds to the output of the forward bending angle detection unit 66 and stops the generation of the assist force by the drive source 54 of the assist force setting unit 68 when the forward bending angle θs becomes a predetermined initial setting value, and sets the output torque of the motor 55 so that the belt 40 is wound by the winding drum 52 with a winding force that eliminates slack in the belt 40 while the generation of the assist force is stopped. The processing circuit 65 has a forward bending angle correction unit 71 that responds to the output of the motor angle detector 57 and corrects the forward bending angle θs based on the motor angle θm.

The processing circuit 65 has a slippage detection unit 72 that responds to the output of the forward bending angle detection unit 66, constantly monitors the forward bending angle θs, and detects the occurrence of slippage of the torque limiter 80 when the forward bending angle θs suddenly changes, a slippage angle calculation unit 73 that responds to the output of the slippage detection unit 72 and determines the slippage angle δ at which the winding drum 52 slips relative to the output shaft 56 of the motor 55, and a motor angle correction unit 74 that responds to the output of the slippage angle calculation unit 73 and corrects the motor angle θm1 immediately before the occurrence of slippage based on the slippage angle δ when it is detected that a slippage has occurred, and provides the corrected motor angle θm2 to the forward bending angle correction unit 71 for correction of the forward bending angle θs.

In another embodiment of the present invention, the slip occurrence detection unit 72 may be realized in a configuration that responds to the outputs of the forward bending angle detection unit 66 and the motor angle detector 57, constantly monitors the difference Δθsm between the forward bending angle θs and the motor angle θm detected by the motor angle detector 57, and detects the occurrence of slip when the difference Δθsm suddenly changes.

The operation unit 76 is operated by the wearer 4 to select and adjust the assist force such as strong, medium, or weak for the lifting posture in the assist force setting unit 68, and the assist force for the squatting posture. The operation unit 76 also selects and sets whether or not the motor 55 generates a torque to prevent slack in the belt 40 when the generation of the assist force in the assist force stopping unit 69 is stopped, by the wearer 4.

10 is a flowchart showing the procedure of the assist suit control process executed by the processing circuit 65 of the wearable assist robot device 1. The processing circuit 65 executes the main loop shown in FIG. 10 at intervals of, for example, 20 ms, and the assist robot device 1 realizes smooth assistance to the wearer 4. When the processing circuit 65 is turned on and power supply to components other than the motor 55 is started, and the processing circuit 65 becomes operable, the processing circuit 65 moves from step s1 to s2, and receives and reads the output from the acceleration sensor 62 and the angular velocity sensor 63 of the motion sensor 61. In step s3, the forward bending angle θs of the trunk 5 is calculated in response to the output of the motion sensor 61. Steps s2 and s3 function as the forward bending angle detection unit 66. The processing circuit 65 reads the motor angle θm, which is the rotation angle of the output shaft 56 of the motor 55, from the motor angle detector 57 provided in the motor 55. In step s4, it is detected that the forward bending angle θs has reached a predetermined value in a forward bending state where the wearer 4 is in an upright position, or a forward bending angle θs that is close to the upright position and is less than 10°, and this forward bending angle θs is stored in the memory of the processing circuit 65 as the initial setting value θs0, and is used as the forward bending angle at which lifting or squatting muscle assistance ends.

Furthermore, in step s5, it is determined whether the operation of generating torque to prevent slack in the belt 40 by the motor 55 has been selected in the operation unit 76 while the generation of such an assist force is stopped. In step s6, when the operation of removing slack in the belt 40 is selected, the output torque of the motor 55 is set so as to wind up the belt 40 with a winding force, for example, 0.5 to 1.0 kgf. Steps s5 and s6 function as part of the assist force setting unit 68. In another embodiment of the present invention, instead of the initially set forward bending angle θs, the motor angle θm of the motor 55 after the belt 40 is wound around the winding drum 52 may be initially set and stored in a memory provided in the processing circuit 65, and may be set as the motor angle θm0 at which muscle assistance for lifting or squatting ends.

In step s7, in response to the output of the object sensor 77, if it is detected that the wearer 4 is grasping an object with the hand 9, in step s8, the forward bending angle θs is read in order to assist in lifting the object or assist in squatting.

In step s9, it is detected whether slippage of the torque limiter 80 has occurred based on the forward bending angle θs. When slippage has occurred, the slippage angle δ at which the winding drum 52 slipped relative to the output shaft 56 of the motor 55 is obtained. The motor angle θm2 immediately after the slippage is calculated and corrected based on the motor angle θm1 immediately before the slippage detected by the motor angle detector 57 and the slippage angle δ (for example, θm2 = θm1 + δ). Based on this corrected motor angle θm2 and the subsequent motor angle θm, the forward bending angle θs thereafter is repeatedly corrected so that the drift error is eliminated. If slippage has not occurred, the forward bending angle θs is repeatedly corrected based on the motor angle θm detected by the motor angle detector 57 so that the drift error is eliminated. The operation of step s9 will be described later with reference to FIG. 11.

In step s10, if the forward bending angle θs of the trunk 5 exceeds a predetermined initial setting value θs0 in the upright state of the wearer 4 or in a forward bending state where the forward bending angle θs approximates the upright state and is less than 10°, the lifting posture is detected. The motion sensor 61 that detects acceleration and angular velocity provides vertical acceleration α1, so after detecting a state where the wearer is not walking, it is determined that the detection is for lifting assistance. In addition, since the vertical acceleration α1 is obtained even when the wearer hits an object, it is determined that the detection is for lifting assistance when the object sensor 77 detects the object within a range (for example, -0.15G to 0.15G) under conditions below a threshold value (for example, 0.15G) where the forward-backward acceleration α2 and the left-right acceleration α3 are not detected. In step s11, if it is detected that the forward bending angle θs continues for a predetermined time W1 or more, the squatting posture is detected. Steps s10 and s11 function as the posture detection unit 67. The posture detection unit 67 includes a timing device, and when the bending angle θs is within a predetermined range for the squatting position, it times the duration of the squatting position, and when the timed duration of the squatting position exceeds a predetermined time W1, the motor 55 winds and pulls the belt 40 around the reel 52 so as to maintain the bending angle θs within the time W1, providing the wearer 4 with a squatting support force moment. Therefore, the wearer 4 can easily maintain the squatting position and can easily perform work in the squatting position.

In step s12, an assist force for the lifting posture, and in step s13, an assist force for the half-squatting posture are applied to the wearer 4 by the motor 55 driving the reel drum 52 via the drive source 54, which reels the belt 40 onto the reel drum 52 and pulls it. Steps s12 and s13 function as an assist force setting unit 68. When the forward bending angle θs measured by the motion sensor 61 becomes, for example, 0, that is, when the wearer stands up straight, if a large lifting assist is applied, the wearer 4 is likely to lose balance, and this state must be avoided. Therefore, the assist torque is calculated to decrease as the forward bending angle θs decreases, and may change small by, for example, a linear or quadratic function.

In step s14, when the forward bending angle θs becomes the predetermined initial setting value θs0, in step s15, the generation of the assist force by the drive source 54 is stopped. Steps s14 and s15 function as the assist force stopping unit 69.

Figure 11 is a flowchart showing specific operations related to the occurrence of slippage and the correction of the forward bending angle θs in step s9 of Figure 10, which are executed by the processing circuit 65. Step r1 is followed by step r2, which detects whether slippage of the torque limiter 80 has occurred. Step r2 functions as the slippage occurrence detection unit 72. When the motor 55 drives the winding drum 52 via the torque limiter 80 in one direction to wind up the belt 40 and provides an assist force to the wearer 4, and the wearer 4 suddenly assumes a bent forward-leaning posture, an excessive tensile force acts on the belt 40. This excessive tensile force is a value that exceeds the assist force for the lifting posture and the half-squat posture, and is a predetermined value in the other direction to unwind and unwind the belt 40 of the winding drum 52, for example, a tensile force of 15 kgf or more. The forward bending angle θs obtained by the forward bending angle detection unit 66 suddenly changes from θs1 to θs2 before and after each predetermined short time ΔW, and the amount of change Δθs (= θs2 - θs1) becomes a large value equal to or greater than the predetermined value Δθs0 (Δθs0 ≦ Δθs). At this time, the occurrence of slippage is detected. As a result, the winding drum 52 generates a slip in the rotation in the other direction by the slip angle δ with respect to the output shaft 56, and the motor 55 is protected.

In step r3, when it is inferred and detected in step r2 that the winding drum 52 has slipped relative to the output shaft 56 of the motor 55, the slip angle δ at which the winding drum 52 has slipped relative to the output shaft 56 of the motor 55 is calculated. Step r3 functions as the slip angle calculation unit 73. Step r3 functions as the slip angle calculation unit 73. As described above, in order to calculate and calculate the slip angle δ, the correspondence between the slip angle δ and the amount of change Δθs is prepared and stored in advance in memory, and the slip angle δ can be obtained from the amount of change Δθs based on that correspondence. Alternatively, the slip angle δ can be calculated by the calculations of equations (1) to (5) with reference to Figures 12 to 14 described below.

If the radius of the winding drum 52 is R, the slip angle of the motor angle θm is δ, and the constant is e, the length L of the belt unwound from the winding drum 52 is given by equation (1).

L ≒ eR (θm + δ) ... (1)
FIG. 12 is a side view of the lumbar vertebrae LB1 to LB5 and their vicinity in the spine of a wearer 4 in an upright position, viewed from the outside left side. The trunk 5 bends forward (to the left in FIG. 12) from the midline vertical line 16. If the five lumbar vertebrae are designated by reference symbols LB1 to LB5 from above, the maximum values of the forward bending angles θB1 to θB5 between them are, for example, as follows according to anatomy. That is, the maximum value of the forward bending angle θB1 between the lumbar vertebrae LB1 and LB2 is 12 degrees. The maximum value of the forward bending angle θB2 between the lumbar vertebrae LB2 and LB3 is 14 degrees. The maximum value of the forward bending angle θB3 between the lumbar vertebrae LB3 and LB4 is 15 degrees. The maximum value of the forward bending angle θB4 between the lumbar vertebrae LB4 and LB5 is 16 degrees. The maximum value of the forward bending angle θB5 between the lumbar vertebrae LB5 and the sacrum below it is 17 degrees. As an example, the bending angle θB4 is illustrated in the following FIG. 13.

Figure 13 is a simplified left side view showing the state in which the wearer 4 is in a bent-forward posture with the five lumbar vertebrae LB1 to LB5 bent. The forward bending angle θs of the entire back is the sum of these bending angles θB1 to θB5.

θs=θB1+θB2+θB3+θB4+θB5 ... (2)
In this FIG. 13, the overall length of the five lumbar vertebrae during forward bending is indicated by LA, and the anterior-posterior length of each of the five lumbar vertebrae is approximately equal and indicated by a constant b.

Figure 14 is a simplified left side view showing the state in which the wearer 4 is standing upright with the five lumbar vertebrae LB1 to LB5 not bending. When standing upright, the forward bending angle θs is 0, and if the total length of the five lumbar vertebrae LB1 to LB5 is L0, the belt length L of the belt 40 along the back is given by formula (3).

L ≒ L0 ... (3)
The total length LA of the five lumbar vertebrae LB1 to LB5 during forward bending is:
LA=L0+b(θB1+θB2+θB3+θB4+θB5)
≒ L0 + bθs ... (4)
Therefore, the belt length L of the belt 40 along the back when bending forward is approximately equal to the above-mentioned LA, as shown in formula (5).

L ≒ L0 + bθs ... (5)
Immediately after slippage of the torque limiter 80 occurs, the forward bending angle θs changes from the previous value θs1 to θs2, and the motor angle θm remains at θm1. The total length L0 of the lumbar vertebrae LB1 to LB5 of the wearer 4 can be treated as a constant. Therefore, the unknown slip angle δ can be found by substituting these values θs2 and θm1 for θs and θm on the right-hand sides of equations (1) and (5), and by eliminating L assuming that the belt lengths L in equations (1) and (5) are equal.

In step r4, the motor angle θm1 immediately before the slip occurs is corrected based on the slip angle δ, and the motor angle θm2 immediately after the slip occurs is calculated. Step r4 functions as the motor angle correction unit 74.

In step r5, the corrected motor angle θm2 and the subsequent motor angle θm are used to correct the forward bending angle θs by eliminating the drift error of the forward bending angle θs. Step r5 functions as the forward bending angle correction unit 71. The forward bending angle θs that is repeatedly corrected in this manner is used to execute the operations from step s10 onward in FIG. 10.

15 is a rear view of a wearable assistive robot device 101 according to another embodiment of the present invention, seen from behind when worn by a wearer 4. This embodiment is similar to the embodiment shown in the above-mentioned FIGS. 1 to 14, and corresponding parts are given the same reference numerals, and are indicated by numbers increased by 100. The trunk holder 120 has a waist support 103 provided on a back member 121. The back member 121 is formed to be relatively large, for example, extending from the upper part of the shoulder blades to the vicinity of the waist and to the vicinity of the upper part of the buttocks. The waist support 103 is provided on the lower part of the back member 121. The waist support 103 is an elongated flat belt-like member that is disposed on the upper part of the waist 11 to surround the waist 11 in a ring shape, and both end portions of the waist support 103 are removably connected by connectors 104 at the front part of the trunk 5. The waist support 103 is disposed on the upper part of the waist 11, and can receive a downward load from the waist 11. The upper part of the waist 11 may be the upper part of the hip bone in the pelvis. For example, a portion of the lumbar support 103 may include the lower part of the back member 121.

The lifting assist force that raises the upper body by pulling the belt 40 and the assist force for maintaining a half-squat posture act in relation to the upper part of the pelvis by the waist support 103, and therefore the lower limbs including the thighs 7. This allows the assist force to be smoothly transmitted to the upper body, which is the trunk 5, so fatigue is reduced.

The trunk support 120 may have a pair of left and right shoulder belts 122 that cover the left and right shoulders of the wearer 4, respectively, and the shoulder belts 122 are attached to the back member 121. In a configuration in which the shoulder belts 122 and the waist support 103 are provided, it is preferable that the shoulder belts 122 have a gap large enough for one or two fingers to fit vertically so that the weight of the wearable assist robot device 101 does not act on the shoulders 12 of the wearer 4. This prevents the waist support 103 from falling when it shifts downward from above the pelvis, and reduces fatigue of the wearer 4 by preventing the load from acting on the shoulders 12 of the wearer 4 from the shoulder belts 122. The shoulder belts 122 may be omitted.

The present invention can be implemented in the following ways:

(1) The belts 40 may consist of two belts, each of which has one end 40a connected to each of the pair of thigh holders 30, and the other end 40b of each of the two belts 40 may be wound and driven by a common winding drum 52. Each of the two belts 40 may also be wound by an individual winding drum 52.

(2) The motion sensor 61 detects the acceleration α or angular velocity ω of a moving body such as the trunk 5, and the forward bending angle detection unit 66 calculates the acceleration α or angular velocity ω, or both α and ω, for example by integration, to calculate and determine a first physical value such as an angle θs that includes a drift error. As the moving body moves, the output shaft 56 of the motor 55 rotates corresponding to the angle θs of the moving body, and the motor angle θm of the output shaft 56 is detected as a second physical value by the motor angle detector 57. The first physical value θs, such as an angle θs that includes a drift error, is corrected using a second physical value such as a motor angle θm that does not include a drift error.

(3) In the above embodiment (2), when the second physical value θm suddenly changes and an error occurs, the second physical value θm1 is corrected based on the first physical values θs1 and θs2 before and after the sudden change, and the first physical value θs is corrected using the corrected second physical value θm2 and the second physical value θm detected thereafter.

(4) Wearable assistive robot devices are used to move and handle objects such as goods and human bodies. For example, they can be used to assist with agricultural work, and can also be used in factories, logistics, construction, nursing care, and walking rehabilitation to restore physical functions. Furthermore, they can be used for snow shoveling in snowy areas. They can also be used for emergency rescue operations during disasters, and for removing disaster waste such as rubble.

LIST OF REFERENCE NUMERALS 1, 101 Wearable assistive robot device 4 Wearer 5 Trunk 7 Thigh 8 Femoral triangle 11 Waist 20, 120 Trunk holder 21, 121 Back member 30 Thigh holder 40 Belt 50 Assist drive mechanism 52 Winding drum 54 Drive source 55 Motor 56 Output shaft 57 Motor angle detector 60 Control unit 61 Motion sensor 65 Processing circuit 66 Forward bending angle detector 67 Posture detector 68 Assist force setting unit 69 Assist force stop unit 71 Forward bending angle corrector 72 Slip occurrence detector 73 Slip angle calculator 74 Motor angle corrector 80 Torque limiter 103 Waist support

Claims (9)

(a) a trunk support having a back member disposed behind the trunk of a wearer and supported by the trunk;
(b) a pair of thigh holders to be worn on the wearer's left and right thighs, respectively, covering the femoral triangle;
(c) a belt that extends vertically along the back of the torso and has a lower end connected to a pair of thigh holders;
(d) an assist drive mechanism provided on the rear member,
(d1) a winding drum to which the other upper end of the belt is fixed and which winds up the belt;
(d2) a drive source,
(d2-1) a motor that drives a winding drum;
(d2-2) a drive source having a motor angle detector that detects a motor angle θm at which the output shaft of the motor rotates;
(d3) a control unit that pulls the belt by a driving source to provide the wearer with a lifting assist force for lifting a load acting on the wearer's hand in a lifting posture,
(d3-1) a motion sensor provided on the back member for detecting the acceleration α or angular velocity ω of the trunk;
(d3-2) A processing circuit,
(d3-2-1) a forward bending angle detection unit that determines a forward bending angle θs of the trunk by integrating the acceleration α or the angular velocity ω in response to an output from a motion sensor;
(d3-2-2) a posture detection unit that detects a lifting posture based on a forward bending angle θs in response to an output of the forward bending angle detection unit;
(d3-2-3) an assist force setting unit that is responsive to an output of the posture detection unit, and that generates, when a lifting posture is detected, an assist force to be applied to the wearer for the lifting posture by a drive source;
(d3-2-4) A wearable assistive robot device including an assist drive mechanism having a control unit including a processing circuit having a forward bending angle correction unit that corrects the forward bending angle θs of the forward bending angle detection unit based on the motor angle θm in response to an output of the motor angle detector. The driving source further includes:
a torque limiter that transmits the power of an output shaft of a motor to a winding drum, and when an excessive tensile force equal to or greater than a predetermined value acts on the belt in the other direction, that is, when the motor drives the winding drum in one direction to wind up the belt, the torque limiter causes the winding drum to slip in the other direction relative to the output shaft;
The processing circuit further comprises:
a slippage occurrence detection unit that detects the occurrence of slippage in the torque limiter;
a slip angle calculation unit that determines a slip angle δ at which the winding drum slips relative to the output shaft of the motor in response to an output of the slip occurrence detection unit;
and a motor angle correction unit that, in response to an output of the slip angle calculation unit, corrects the motor angle θm1 immediately before the occurrence of the slip based on the slip angle δ when the occurrence of a slip is detected, and provides this corrected motor angle θm2 to the forward bending angle correction unit for correcting the forward bending angle θs. The slip occurrence detection unit is
The wearable assistive robot device according to claim 2, characterized in that the forward bending angle θs is constantly monitored in response to the output of the forward bending angle detection unit, and the occurrence of slippage is detected when the amount of change Δθs (= θs2 - θs1) of each of the values θs1, θs2 before and after the forward bending angle θs that has suddenly changed significantly within a predetermined short period of time ΔW becomes greater than or equal to a predetermined value Δθs0. The slip occurrence detection unit is
in response to the outputs of the forward bending angle detection unit and the motor angle detector, constantly monitoring a difference Δθsm between the forward bending angle θs detected by the forward bending angle detection unit and the motor angle θm detected by the motor angle detector 57;
3. The wearable assistive robot device according to claim 2, wherein the occurrence of slippage is detected when the difference Δθsm changes suddenly. The slip angle calculation unit is
The wearable assistive robot device according to claim 2, further comprising a memory for storing a correspondence relationship between the slip angle δ and the amount of change Δθs (=θs2-θs1) of the forward bending angles θs1 and θs2 before and after a sudden change in the forward bending angle θs, and the slip angle δ is calculated from the amount of change Δθs. The slip angle calculation unit is
The wearable assistive robot device according to claim 2, characterized in that the slip angle δ is calculated by determining that the belt length L of the belt unwound from the winding drum of radius R by rotation at the motor angle θm1 and slip angle δ just before the occurrence of slippage is equal to the total length LA of the five lumbar vertebrae LB1 to LB5 at the forward bending angle θs2 just after the occurrence of slippage. The posture detection unit further detects a half-squatting posture when the forward bending angle θs continues for a predetermined time W1 or more.
2. The wearable assistive robot device according to claim 1, wherein the assist force setting unit is further configured to respond to an output of the posture detection unit, and when a squatting posture is detected, generate an assist force to be applied to the wearer for the squatting posture by using the drive source. The wearable assistive robot device according to claim 1, characterized in that the processing circuit further has an assist force stopping unit, which responds to the output of the forward bending angle detection unit, stops the generation of the assist force by the drive source of the assist force setting unit when the forward bending angle θs becomes a predetermined initial setting value, and sets the output torque of the motor so that the belt is wound up by the winding drum with a winding force that eliminates slack in the belt while the generation of the assist force is stopped. The belt is a single piece, one end of which is connected to a pair of thigh holders,
2. The wearable assistive robot device according to claim 1, wherein the trunk support has a waist support provided on the back member, the waist support being placed on the upper part of the hip bone in the pelvis of the waist to surround the waist and to receive a downward load at the waist.