JP2009183407A - Walking aid device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a walking aid device which makes direct advancing-turning movements with easy operation. <P>SOLUTION: The walking aid device 1 includes in-wheel motors 4A-4D for driving to rotate four wheels provided on both right and left sides of a frame body having a handle part, a touch-sensitive sensor 10 for detecting whether a walking person holds the handle part, and a controller 11. The controller 11 detects back electromotive force generated in the in-wheel motors 4A-4D, obtains wheel speed command values for respective wheels based on the back electromotive force, and controls the in-wheel motors 4A-4D to drive respective wheels in accordance with the wheel speed command values. In addition, the controller 11 controls the in-wheel motors 4A-4D to brake the respective wheels when determining that the walking person does not hold the handle part based on the detected signal by the touch-sensitive sensor 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a handcart-type walking assist device that rotates wheels by a drive motor.

As a conventional wheelbarrow-type walking assist device, for example, as described in Patent Document 1, a pair of left and right force detectors for detecting a force applied to a handle portion by a pedestrian is provided, and each force detector is provided with each force detector. It is known that a driving mechanism is controlled to increase the speed of the driving wheel on the side opposite to the bending direction in accordance with the generated force response difference so that the pedestrian turns in the direction that the pedestrian wants to turn.
Japanese Patent No. 3156367

  However, in the above-described prior art, controlling the force applied to the left and right sides of the handle portion so that the walking assist device advances in the direction in which the pedestrian wants to travel is problematic in that it is complicated and difficult for the elderly. is there.

  An object of the present invention is to provide a walking assistance device that can perform straight traveling and turning operations with a simple operation.

  The walking assist device of the present invention includes a frame body having a handle portion gripped by a pedestrian, a plurality of wheels provided on the left and right sides of the frame body, a plurality of drive motors for rotating each wheel, and a drive motor. And a control means for detecting the counter electromotive force generated and controlling the drive motor based on the counter electromotive force.

  In the present invention, when torque is applied to the wheel by the pedestrian pushing the handle, a back electromotive force is generated in the drive motor, and the back electromotive force is detected by the control means. Based on this, the drive motor is controlled. For example, when torque is applied to the right wheel, a back electromotive force is generated in the drive motor that drives the right wheel to rotate. Therefore, the drive motor is controlled so that the right wheel is accelerated. Turn left. Thus, it is determined that the operation of the walking assist device has been performed due to the back electromotive force generated in the drive motor, and the pedestrian is applied to both the left and right sides of the handle portion by controlling the drive motor based on the back electromotive force. There is no need to fine-tune the force. As a result, the walking assist device can be moved straight and turned with a simple operation. In addition, since a force detector that detects the force applied to the left and right sides of the handle portion is not necessary, the cost of the walking assist device can be reduced.

  Preferably, when the turning operation is started, the control means decelerates the wheel on the turning outer wheel side according to the wheel speed difference between the wheel on the turning outer wheel side and the wheel on the turning inner wheel side, and according to the wheel speed difference. The drive motor is controlled so as to increase the speed of the wheel on the inner turning side.

  When turning the walking assist device, if only the wheel on the turning outer wheel side is accelerated, the walking assist device continues to turn. Therefore, when the turning operation of the walking assist device is started, the wheel on the turning outer wheel side is decelerated according to the difference between the left and right wheel speeds, and the wheel on the turning inner wheel side is increased according to the difference between the left and right wheel speeds. By doing so, it is prevented that the walking assistance device continues to turn, and the straightness of the walking assistance device is improved.

  In addition, preferably, it further includes detection means for detecting whether or not the pedestrian is holding the handle portion, and the control means brakes the wheel when the detection means does not detect that the pedestrian is holding the handle portion. The drive motor is controlled so that

  In this case, when the pedestrian releases his / her hand from the handle portion while the walking assist device is running, the walking assist device is forcibly stopped. Further, even if the pedestrian releases his / her hand from the handle on the slope, each wheel remains in a braked state, so that the walking assist device is prevented from moving due to the counter electromotive force generated in the drive motor.

  Further, preferably, the plurality of wheels are respectively attached to the front side and the rear side of the frame body, and the control means rotationally drives the counter electromotive force generated in the drive motor that drives the front wheels to rotate and the rear wheels. It is determined whether or not the difference from the counter electromotive force generated in the drive motor to be driven is greater than a predetermined value. If the difference is greater than the predetermined value, the drive motor is controlled to brake the wheel.

  For example, when the walking assist device passes through a step or a hole, the difference between the torque applied to the front wheel and the torque applied to the rear wheel increases. Therefore, when the difference between the back electromotive force generated in the drive motor that rotationally drives the front wheels and the back electromotive force generated in the drive motor that rotationally drives the rear wheels is greater than a predetermined value, the wheels are braked. By doing so, the walking assistance device can be stopped when the walking assistance device passes through a step or the like.

  According to the walking assist device of the present invention, it is possible to perform a straight traveling / turning operation with a simple operation. This makes it possible to reduce the burden on particularly elderly pedestrians.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a walking assistance device according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of an embodiment of a walking assistance device according to the present invention, and FIG. 2 is a side view of the walking assistance device shown in FIG. In each figure, the walking assistance apparatus 1 of this embodiment is an electric handcart which assists a pedestrian to walk.

  The walking assist device 1 is attached to the frame body 2, the wheels 3A to 3D provided on the left and right sides of the frame body 2, and the inner sides of the wheels 3A to 3D, and independently rotates the wheels 3A to 3D. Electric in-wheel motors 4 </ b> A to 4 </ b> D (see FIG. 3) to be driven and a power supply unit 5 that is attached to the frame body 2 and also serves as a luggage compartment for accommodating luggage.

  The frame body 2 includes a handle portion 6 held by a pedestrian, a pair of main frames 7 extending from both ends of the handle portion 6 diagonally downward on the front side, and extending obliquely downward on the rear side from a substantially central portion of each main frame 7. A pair of sub-frames 8 and a pair of joint portions 9 that respectively connect the sub-frames 8 to the main frames 7 so as to freely rotate (open and close).

  In-wheel motors 4A and 4B (see FIG. 3) for rotating and driving the wheels (front wheels) 3A and 3B are attached to the lower ends of the main frames 7, respectively. In-wheel motors 4C and 4D (see FIG. 3) for rotating and driving the wheels (rear wheels) 3C and 3D are attached to the lower ends of the sub-frames 8, respectively.

  The joint portion 9 is provided with an electric motor (not shown) that rotates the subframe 8 with respect to the main frame 7. The power supply unit 5 is suspended from the joint portion 9.

  In addition, as shown in FIG. 3, the walking assist device 1 further includes a touch sensor 10 and a controller 11 connected to each of the in-wheel motors 4 </ b> A to 4 </ b> D and the touch sensor 10. The touch sensor 10 is provided on the handle portion 6 and detects whether or not a pedestrian is holding the handle portion 6.

  The controller 11 detects the counter electromotive force generated in the in-wheel motors 4A to 4D, inputs a detection signal of the touch sensor 10, performs a predetermined process, and controls the in-wheel motors 4A to 4D. The controller 11 may be built in the handle portion 6 or may be provided in the power supply unit 5.

  FIG. 4 is a flowchart showing details of the motor control processing procedure executed by the controller 11. Note that this process is executed both when the walking assist device 1 is stopped and when it is running.

但し、Ｅはインホイールモータ４Ａ〜４Ｄに生じる逆起電力（電圧）であり、Ａは定数である。 In the figure, it is first determined whether or not back electromotive force is generated in the in-wheel motors 4A to 4D (step S101). When back electromotive force is generated in the in-wheel motors 4A to 4D, the rotational speed V of the wheels 3A to 3B is obtained by the following formula, and this rotational speed V is used as a wheel speed command value to be given to the in-wheel motors 4A to 4D ( Step S102).

However, E is a counter electromotive force (voltage) generated in the in-wheel motors 4A to 4D, and A is a constant.

  Specifically, when torque is generated in the wheels 3A to 3D, for example, a counter electromotive force (voltage) as shown in FIG. 5A is generated in the in-wheel motors 4A to 4D. As shown, wheel speed command values for increasing the speed of the wheels 3A to 3D are obtained.

  And in-wheel motor 4A-4D is controlled so that wheel 3A-3D may be rotationally driven according to the wheel speed command value obtained by procedure S102 (procedure S103).

  At this time, when the torque applied to the wheels 3A to 3D is the same, the back electromotive force generated in the in-wheel motors 4A to 4D is equivalent, so the wheel speed commands for the wheels 3A to 3D to be given to the in-wheel motors 4A to 4D The values are equal and the walking assist device 1 goes straight.

  For example, when the right wheels 3B and 3D are pressed strongly, the counter electromotive force generated in the in-wheel motors 4B and 4D becomes higher than the counter electromotive force generated in the in-wheel motors 4A and 4C. A wheel speed command value that increases the speed of 3D is obtained, and as a result, the walking assist device 1 turns left. However, if the rotational speeds of the wheels 3 </ b> A to 3 </ b> D remain constant, the walking assist device 1 continues to turn, so that the straightness of the walking assist device 1 is deteriorated.

  For this reason, in step S102, the counter electromotive force generated in the in-wheel motors 4B and 4D corresponding to the right wheels 3B and 3D and the counter electromotive force generated in the in-wheel motors 4A and 4C corresponding to the left wheels 3A and 3C, When the difference is larger than a predetermined value, it is determined that the vehicle has been turned, and the speed change rate of the wheels 3A to 3D is obtained by the following formula, and the rotational speed of the wheels 3A to 3B is taken into consideration with the speed change rate. (Wheel speed command value) V is obtained.

Speed change rate of turning outer wheel ΔV _out = −B × (Rotation speed of turning outer wheel−Rotation speed of turning inner wheel) Speed change rate of turning inner wheel ΔV _in = B × (Rotation speed of turning outer wheel−Rotation speed of turning inner wheel)
However, B is a constant.

Specifically, as shown in FIG. 6, the turning outer wheel (see P in the figure) decelerates in accordance with the speed change rate ΔV _out and the turning inner ring (in the figure) from the time t when the rotational speed of the turning outer wheel rises sufficiently. Q reference) is increased according to the speed change rate ΔV _in , and a wheel speed command value is obtained so that the rotational speeds of the outer turning wheel and the inner turning wheel are finally equal.

  Accordingly, for example, when the right wheels 3B and 3D are strongly pressed and the right wheels 3B and 3D are increased in speed, the walking assist device 1 starts to turn left. Wheels 3B and 3D decelerate in proportion to the difference between the left and right wheel speeds (rotational speed of the outer turning wheel-rotational speed of the inner turning wheel), and the left wheels 3A and 3C, which are inner turning wheels, increase in proportion to the left and right wheel speed difference. And finally the rotational speeds of the wheels 3A to 3D become equal. As a result, the walking assist device 1 smoothly moves straight ahead.

  Subsequently, based on the detection signal of the touch sensor 10, it is determined whether or not the pedestrian is grasping the handle portion 6 (step S104). When it is determined that the pedestrian is not gripping the handle portion 6, the in-wheel motors 4A to 4D are controlled so as to brake the wheels 3A to 3D (step S105).

  Thereby, when the pedestrian releases his / her hand from the handle portion 6, even if the walking assist device 1 is running, it is forcibly and promptly stopped. At this time, it is desirable to brake the wheels 3A to 3D so that the walking assist device 1 does not stop suddenly. In addition, when the pedestrian releases his hand from the handle portion 6, the wheels 3A to 3D remain braked even on a slope, and thus the wheels 3A to 3D are rotationally driven by the counter electromotive force generated in the in-wheel motors 4A to 4D. Therefore, there is no problem that the walking assist device 1 goes down the slope.

  On the other hand, when it is determined in step S104 that the pedestrian is grasping the handle portion 6, the back electromotive force generated in the in-wheel motors 4A and 4B corresponding to the front wheels 3A and 3B and the rear wheels 3C and 3D are subsequently supported. It is determined whether or not the absolute value of the difference from the counter electromotive force generated in the in-wheel motors 4C and 4D to be performed is equal to or less than a preset threshold value (step S106). When it is determined that the absolute value of the difference between the counter electromotive force generated in the in-wheel motors 4A and 4B and the counter electromotive force generated in the in-wheel motors 4C and 4D is larger than the threshold value, the wheels 3A to 3D are braked. The in-wheel motors 4A to 4D are controlled (procedure S105).

  When the walking assist device 1 moves forward, for example, as shown in FIG. 7, when the walking assist device 1 passes through a step X that becomes lower toward the front, the front wheels 3 </ b> A and 3 </ b> B are preceded by the rear wheels 3 </ b> C and 3 </ b> D. Will go down. At this time, since the torque applied to the front wheels 3A and 3B is larger than the torque applied to the rear wheels 3C and 3D, as shown in FIG. 8, the counter electromotive force generated in the in-wheel motors 4A and 4B corresponding to the front wheels 3A and 3B. The absolute value of R (see R in the figure) is larger than the absolute value of the back electromotive force (see S in the figure) generated in the in-wheel motors 4C, 4D corresponding to the rear wheels 3C, 3D.

  In this case, the wheels 3A to 3D are braked by the in-wheel motors 4A to 4D, and the walking assist device 1 immediately stops, so that the front wheels 3A and 3B are prevented from entering the step X and falling. As a result, the influence on the pedestrian can be sufficiently reduced.

  On the other hand, when it is determined in step S106 that the absolute value of the difference between the counter electromotive force generated in the in-wheel motors 4A and 4B and the counter electromotive force generated in the in-wheel motors 4C and 4D is equal to or less than the threshold value, it is given to the pedestrian. The walking assist device 1 is allowed to travel as it is with little influence.

  As described above, in the present embodiment, when the back electromotive force generated in the in-wheel motors 4A to 4D is detected, it is determined that the pedestrian has pushed the handle 6 and the back electromotive force is determined. The wheel speed command values of the wheels 3A to 3D are obtained based on the electric power, and the in-wheel motors 4A to 4D are controlled according to the wheel speed command values. For this reason, unlike the case where the walking assist device 1 is operated by detecting the pressure applied to the handle 6, the pedestrian does not need to finely control the force applied to the left and right sides of the handle 6. Thereby, especially for elderly people, the walking assistance device 1 can be moved straight and turned with a simple operation.

  Moreover, since it is not necessary to use the sensor which detects the pressure applied to the handle | steering-wheel part 6, the number of parts required for the walk assistance apparatus 1 can be reduced, and the cost concerning the walk assistance apparatus 1 can also be held down.

  The present invention is not limited to the above embodiment. For example, although the four wheels 3A to 3D are provided in the walking assist device 1 of the above embodiment, a three-wheel structure or the like in which one of the front wheels and the rear wheels is one may be used.

It is a perspective view which shows the external appearance of one Embodiment of the walk assistance apparatus concerning this invention. It is a side view of the walking assistance apparatus shown in FIG. It is a block diagram which shows the control system of the walking assistance apparatus shown in FIG. It is a flowchart which shows the detail of the motor control processing procedure performed by the controller shown in FIG. It is a graph which shows an example of the counter electromotive force which arises in an in-wheel motor, and the rotational speed given to a wheel at that time. It is a graph which shows an example of the rotational speed given to a wheel on either side at the time of turning. It is a side view which shows a mode that a walking assistance apparatus passes a level | step difference. It is a graph which shows an example of the counter electromotive force which arises in the in-wheel motor corresponding to a front and back wheel, when a walk auxiliary device passes a level difference.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Walking assistance apparatus, 2 ... Frame body, 3A-3D ... Wheel, 4A-4D ... In-wheel motor (drive motor), 6 ... Handle part, 10 ... Touch sensor (detection means), 11 ... Controller (control means) .

Claims (4)

A frame body having a handle portion gripped by a pedestrian;
A plurality of wheels provided on both left and right sides of the frame body;
A plurality of drive motors for rotating each of the wheels;
A walking assistance device comprising: a control unit that detects a counter electromotive force generated in the drive motor and controls the drive motor based on the counter electromotive force.   When the turning operation is started, the control means decelerates the wheel on the turning outer wheel side according to the wheel speed difference between the wheel on the turning outer wheel side and the wheel on the turning inner wheel side, and according to the wheel speed difference. The walking assist device according to claim 1, wherein the driving motor is controlled so as to increase the speed of the wheel on the inner turning side. Detection means for detecting whether or not the pedestrian is gripping the handle part,
The said control means controls the said drive motor so that the said wheel may be braked when it is not detected by the said detection means that the said pedestrian is grasping the said handle | steering-wheel part. The walking aid device described. The plurality of wheels are respectively attached to the front side and the rear side of the frame body,
The control means determines whether or not a difference between a back electromotive force generated in the drive motor that rotationally drives the front wheel and a back electromotive force generated in the drive motor that rotationally drives the rear wheel is greater than a predetermined value. And when the said difference is larger than the said predetermined value, the said drive motor is controlled so that the said wheel may be braked, The walk assistance apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.

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