JP2007176195A - Electric-assisted truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric-assisted truck capable of mechanically detecting the push-pull force of a worker by a simple mechanism, and assisting not only the forward and backward movements but also the right-to-left turning or meandering operation thereof. <P>SOLUTION: The electric-assisted truck 1 comprises right and left electric-assisted driving means 10L, 10R for providing the auxiliary power to a pair of right and left rear wheels 20L, 20R, plate members 33L, 33R as right and left deformation recovering members interposed between a truck part 5 and a grip bar 31, right and left strain gage sensors 36L, 36R mounted on each of the right and left plate members, and a microcomputer for respectively controlling the right and left motors according to the output signals of the strain gage sensors. The microcomputer controls the rotational speeds of the right and left motors to be the same if the difference of the output signals of the strain gage sensors is in a predetermined range. If the difference of the output exceeds the predetermined range, the assist control of turning or meandering is performed by performing the control of realizing the different rotational speed of the right and left motors. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric assist cart.

  In general, a cart used in a factory or the like places a heavy load, and thus requires a large force at the start of transportation, which is a heavy labor for an operator. In view of this problem, as in the so-called electrically assisted bicycle, an electrically assisted trolley that detects an operator's force and assists with an electric force according to human power has been developed.

  For example, Japanese Patent Application Laid-Open No. 10-109647 discloses an electric assist cart 1 including an assist device that biases a running force to a normal cart. The electric assist cart 1 has an operation torque information input means 7a for inputting operation torque information, an operation torque information detection means 9 for detecting operation torque information, and a traveling that outputs a running force according to the detected operation torque information. A force output unit 11.

  One end of the operation torque information input means 7 a is rotatably supported by the support portion 14, and is sandwiched by a pair of spring members 23 from both the left and right sides. When no torque is input to the operation torque information input means 7a, the operation torque information input means 7a is positioned substantially at the center, and the rotational position of the operation torque information input means 7a depends on the magnitude of the input torque. Determined.

  The operating torque information detecting means 9 is provided with a position detecting potentiometer 8. The protruding portion of the rotatable arm extending from the potentiometer 8 is engaged with the elongated hole 14a of the operation torque information input means 7a, and thereby the rotational position of the operation torque information input means 7a, that is, the input torque is obtained. Can be detected.

  When changing the traveling direction of the electric assist cart, the user manually rotates the assist device 5 around the direction changing member 19. Thereby, the direction of the driving wheel 14 itself is changed, and the traveling direction of the electric assist cart 1 can be changed.

Japanese Patent Application Laid-Open No. 11-124037 discloses an electric auxiliary transport vehicle in which a motor and a battery are attached to a hand-held single-wheel transport vehicle or a two-wheel transport vehicle, and auxiliary power is generated by the motor in accordance with a manual operation force. Yes. This electric auxiliary transport vehicle includes a sliding grip 11R, an elastic member 47 that pushes the grip toward the operator, and a body frame at either end of left and right operation handles 7L and 7R extending rearward and upward from the body frame. A movement amount detection unit 62 that detects the movement amount of the grip toward the head, and a control unit that controls the motor 5 according to the output of the movement amount detection unit.
JP-A-10-109647 Japanese Patent Laid-Open No. 11-124037

  However, in the above-described conventional technology, the means for detecting the force of the worker is mechanically large, and nevertheless, the steering of the electric assist cart is still left only to the force by the worker.

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide an electric assist cart that can detect an operator's force with a mechanically simpler mechanism.

  Furthermore, another object of the present invention is to provide an electric assist cart that can assist not only forward and backward but also the left and right turning motion of the electric assist cart.

  In order to solve the above-described problem, an aspect of the present invention is an electric assist cart having at least a pair of left and right wheels, each provided with left and right drive means for providing auxiliary power to the pair of left and right wheels, and a cart portion. Alternatively, the left and right deformation recovery members interposed between the wheel and the handle operating portion, the left and right distortion detection means attached to the left and right deformation recovery members, and the output signals of the left and right distortion detection means Control means for individually controlling the left and right drive means.

  According to the present invention, since the control means controls the left and right drive means according to the output signals of the left and right distortion detection means, it assists any operation of the carriage forward, backward, and left and right turning accurately. be able to. For example, the left and right deformation recovering members are distorted by different amounts in accordance with the user's left and right turning or bending operations, so that the output signals of the left and right distortion detecting means are different on the left and right. The rotation assist operation can be performed by controlling the rotation speeds of the left and right drive units to be different from each other in accordance with output signals indicating different distortions. In addition, the direction in which the deformable member is distorted and the output signal changes according to the forward and backward operations of the user, so that the forward or backward movement can be achieved by rotating the driving means forward or backward accordingly. Assist operation is possible. In other words, the control means determines whether the left and right distortion detection means output the left and right in either the rotational direction in which the electric assist cart moves forward or the rotational direction in which the electric assist cart moves backward, depending on whether the deformation recovering member is pushed or pulled. The drive means are individually controlled.

  In a preferred embodiment, the control means controls the rotational speeds of the left and right drive means to be the same when the difference between the output signals of the left and right distortion detection means is within a predetermined range. As a result, frequent turning assist operations can be avoided, and more stable forward or reverse assist operations can be performed. Conversely, when the difference between the output signals of the left and right distortion detection means exceeds a predetermined range, the control means causes the left and right drive means to rotate at a speed corresponding to each of the output signals of the left and right distortion detection means. It is preferable to control each of them.

  The deformation recoverable member is a member that deforms at least one of, for example, expansion / contraction deformation, warpage bending deformation, and uneven deformation when force is applied, and returns to its original shape when no force is applied. Have Specifically, the deformation recovery member includes a spring member, an elastic member, a plate member, and the like, and a desirable mode is a rectangular parallelepiped metal plate. Examples of the strain detection means include a strain gauge sensor, a position sensor, a stress sensor, a piezoelectric resistance sensor, and an electrical resistance sensor.

  In the above aspect, the electric assist cart may further include a front wheel, the handle operation portion may be attached to the rear of the cart portion, and the pair of left and right wheels may be rear wheels. The front wheels may be either single wheels or two wheels.

  Another aspect of the present invention is an electric assist cart having at least one wheel, comprising at least one drive means provided to provide auxiliary power to the wheel, and the cart portion or the wheel and the handle operation portion. At least one deformation recovering member interposed therebetween, at least one strain detecting means for detecting strain of the deformation recovering member, and distortion of the deformation recovering member detected by the strain detecting means. And a control means for controlling the drive means accordingly.

  The electric assist cart in this aspect is not limited to one having a pair of left and right wheels. For example, there may be one wheel and it may be configured as a unicycle carriage. Of course, it may be configured as a three-wheeled carriage with three wheels, and may have other number of wheels. Accordingly, it is not necessary to provide the driving means on each of the left and right wheels. One driving means may be provided on at least one wheel, or may be provided on each of three or more wheels. Furthermore, in the electric assist cart of this aspect, it is not necessary to provide a pair of left and right deformation recovery members, and at least one deformation recovery member may be provided. The same applies to the distortion detection means. For example, any number of deformation recoverable members, any number of distortions can be used as long as the deformation differences of the deformation recoverable members caused by operations on the electric assist cart such as forward, reverse and left and right turn operations can be distinguished from each other. Arbitrary attachment modes of the detection means and the deformation recovery member and arbitrary arrangement modes of the strain detection means can be used.

  In the above aspect, the control means performs forward control and reverse control of the drive means in accordance with whether the deformation of the deformation recoverable member indicates forward or backward movement with respect to the electric assist cart.

  In one preferable aspect for turning the carriage, the driving means for turning or bending at least one wheel to the left and right is provided, and the control means has a distortion of the deformation recoverable member with respect to the electric assist carriage. The turning drive means is controlled according to which of the left and right turning or bending operations is shown.

  In another preferred embodiment for turning the carriage, at least one wheel is provided on each of the left and right sides, the drive means is provided so as to give auxiliary power to each of the left and right wheels, and the control means is modified. The left and right rotational speeds of the driving means are controlled differently depending on whether the distortion of the recoverable member indicates the left or right turning or bending operation with respect to the electric assist cart. In this aspect, preferably, when the distortion of the deformable member that exhibits the turning or bending operation is within a predetermined range, the control unit controls the rotational speed of each of the driving means to be the same, and the turning or bending operation is performed. When the distortion of the deformation recoverable member indicating exceeds the predetermined range, each of the driving means is controlled to have a different rotational speed.

  The rotational speed of the driving means may be determined based on the magnitude of the output signal of the distortion detecting means, and the rotational direction of the driving means may be determined based on the sign of the output signal of the distortion detecting means.

  The drive means is provided between the motor gear and the wheel gear, as an example, a motor, a motor gear for transmitting the output of the motor, a wheel gear attached so as to rotate coaxially with the wheel, and the wheel gear. Drive transmission means such as a chain, belt or gear.

  Other objects and advantages of the present invention will be understood more clearly by reference to the preferred embodiments of the present invention described below.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  1A and 1B are a rear view and a side view, respectively, of an electric assist cart 1 according to an embodiment of the present invention. As shown in the figure, the electric assist cart 1 includes a cart unit 5 for carrying a load, a pair of left and right front wheels 22L and R, a pair of left and right rear wheels 20L and R, and a handle operating unit 30 that a user has. And comprising. The electric assist cart 1 is shown as an example for carrying a heavy dumbbell, and a lower dumbbell carrier 6 and an upper dumbbell carrier 8 are provided in the cart portion 5. Each of the lower dumbbell carrier 6 and the upper dumbbell carrier 8 has a plurality of pairs of ridges 24 and 25, and the dumbbells 26 and 28 can be arranged between a plurality of grooves formed between the ridges. It has become.

  Electric assist driving means 10L and 10R are respectively attached to the bottom surface of the carriage unit 5 inside the pair of left and right rear wheels 20L and R in the axial direction. The electric assist driving means 10L and R accommodate motors 37L and R (see FIG. 3), respectively, and the motor gears 12L and R for transmitting the outputs of the motors 37L and R are electric assist driving means 10L. , R so as to protrude to the outside. The electric assist driving means 10L, R may further have a reduction gear between the motors 37L, R (see FIG. 3) and the motor gears 12L, R. Between these motor gears 12L, R and wheel gears 18L, R attached so as to rotate coaxially with the rear wheels 20L, R, chains 16L, R as an example of drive transmission means are respectively stretched. Has been. As a result, the auxiliary power of the motors 37L, R can be independently transmitted to the rear wheels 20L, R.

  In addition, a battery bracket 13 is attached to the bottom of the carriage unit 5, and a battery 17 is attached to the battery bracket 13 in a detachable manner. The motors 37L and R are wired so that power is supplied by the battery 17.

  FIG. 2 shows a top view of the handle operating unit 30. The handle operating unit 30 includes a grip bar 31 that is gripped by a user of the carriage, a pair of support bars 32L and R that respectively support the left and right ends of the grip bar 31, and an oblique direction from the rear of the carriage section 5. A pair of plate members 33L, R as an example of a deformable member connected between the extending cart bars 35L, R and the support bars 32L, R and the cart bars 35L, R via bolts 40; It has. The plate members 33L and R are warped, bent, and deformed according to an external force, but have deformation recovery properties.

  Strain gauge sensors 36L and R, which are examples of strain detecting means, are attached to the plate members 33L and R, respectively. The strain gauge sensor 36 outputs a signal corresponding to the strain of the plate member 33. That is, the magnitude of the output signal of the strain gauge sensor 36 increases in relation to the amount of strain of the plate member 33, that is, the magnitude of the user's push-pull force. Further, the plus / minus sign of the output signal indicates the type of distortion of the plate member 33, that is, whether the user is pushing or pulling the carriage. Thereby, for example, when the output signal of the strain gauge sensor has a plus sign, it can be determined that the user has distorted in the direction in which the plate member 33 contracts by pushing the carriage forward, and conversely the output signal is When it has a minus sign, it can be determined that the user is distorted in the direction in which the plate member 33 extends by pulling the carriage rearward.

  Here, the “deformation recoverability” of the plate member means that the plate member brought about by the pushing / pulling force on the grip bar 31 of the user is distorted to a level that can be detected by the strain gauge sensor, and the pushing / pulling force disappears. The characteristic that returns to the original shape. As long as it has this characteristic, the deformation recovery member can be made of any suitable material and shape using a spring member, an elastic member, or a plate member. Preferably, the deformation recovery member is made by, for example, forming a metal material such as stainless steel on a rectangular parallelepiped plate, and is arranged so that the long side thereof coincides with the longitudinal direction of the carriage. By adopting a rectangular parallelepiped shape in this way, the left and right plate members 33L and R can effectively detect the pushing and pulling force of the user on each of the left and right sides.

  Next, the outline of the control system of the electric assist cart 1 is shown in FIG. The control system of the electric assist cart 1 is directly connected to one microcomputer 14 that collectively controls the electronic processing of the entire cart, the left and right motors 37L and 37R that can be PWM controlled, and the microcomputer 14. And amplifying circuits 15L, 15A that amplify the power of the control signals to the left and right motors 37L, 37R, and the battery 17 described above connected to the amplifying circuit.

  The microcomputer 14 receives strain gauge sensor output signals 1 and 2 from the strain gauge sensors 36L and 36R. Based on these signals, the microcomputer 14 determines the rotation speed and rotation direction of the motors 37L, R, and outputs a PWM command to each motor. Here, the magnitudes of the output signals 1 and 2 of the strain gauge sensor and the rotation speeds of the motors 37L and R may be mapped with a certain functional relationship. For example, in a predetermined range of the output signal, the functional relationship is set so that the rotation speed of the motor increases as the output signal of the strain gauge sensor increases. The correspondence relationship between the sign of the output signal of the strain gauge sensor and the rotation direction of the motor is also mapped.

  Next, the control flow of the electric assist cart 1 will be described with reference to the flowchart of FIG.

  As shown in FIG. 4, first, output signals from the left and right strain gauge sensors 36L, R are read (step 100). Next, a difference between the read output signals is calculated, and it is determined whether or not the output difference exceeds a predetermined threshold Th (step 102). When the output difference exceeds the predetermined threshold Th (affirmative determination in step 102), the rotational speeds and rotational directions of the left and right motors 37L, R according to the respective output signals from the left and right strain gauge sensors 36L, R. To control each. For example, when both output signals of the strain gauge sensors 36R, L have a plus sign, it indicates that the user is going to move the carriage 1 forward, so the left and right motors 37L, R It is controlled to rotate in the forward direction. At this time, if the output signal of the right sensor 36R is larger than the output signal of the left sensor 36L, it indicates that the user is going to turn the carriage 1 to the left, so the rotational speed of the right motor 37R is The rotational speed of the left motor 37L is increased in the forward direction. Thereby, the cart 1 can be turned or bent to the left in the forward direction. Conversely, when the output signal of the left sensor 36L is larger than the output signal of the right sensor 36R, the rotational speed of the left motor 37L is increased in the forward direction relative to the rotational speed of the right motor 37R, and the carriage 1 is moved forward. Can turn or bend to the right.

  Further, when both output signals of the strain gauge sensors 36R, L have a minus sign, it indicates that the user is going to move the cart 1 backward, so the left and right motors 37L, R are moved in the reverse direction. Controlled to rotate. Also at this time, since the outputs of the strain gauge sensors 36R and 36L are different, control is performed so that the rotational speeds of the left and right motors 37 differ according to each output signal. As a result, it is possible to turn left or right in the reverse direction.

  Further, when one of the output signals of the strain gauge sensors 36R, L has a plus sign and the other has a minus sign, one of the motors corresponding to the plus output is controlled in the forward direction so that the minus output is obtained. The corresponding other motor is controlled in the reverse direction. As a result, turning or bending operation of the cart 1 having a small turning radius can be performed.

  If the output difference of the strain gauge sensor is equal to or smaller than the predetermined threshold Th in Step 102 (No determination in Step 102), the sign of the strain gauge sensor output signal is determined (Step 106). If both the left and right strain gauge sensor output signals are positive, control is performed with the same rotational speed of the left and right motors 37L and R in the forward direction of the carriage 1 (step 108). Conversely, if both the left and right strain gauge sensor output signals are negative, the same speed control of the left and right motors is performed in the backward direction of the carriage 1 (step 112). Note that the same rotational speed of the left and right motors at this time may be determined based on either one of the left and right strain gauge sensor output signals or the average value of both signals. In this way, when the output difference is significantly small, by controlling the left and right motors at the same speed, frequent turning motions caused simply by left and right force variations by the user can be avoided accurately and more stable. The straight-ahead assist control can be performed.

  In step 106, if the output signals of the left and right strain gauge sensors are both zero, or if one is positive and the other is negative, the left and right motors are stopped (step 110). Here, the determination of whether or not the output signal is zero may be performed depending on whether or not the output signal is within a predetermined range including zero. Thus, unless a force exceeding a certain level is applied, the left and right drive means for providing auxiliary power to the pair of left and right wheels do not work, and the assist operation is not performed. Thus, frequent assist operations can be avoided.

  Next, returning to step 100, the same processing is repeated.

  The above is the embodiment of the present invention, but the present invention is not limited to the above-described example, and can be arbitrarily modified within the scope of the gist of the present invention.

  For example, in the above example, the electric assist drive means 10L, R are attached to the rear wheel side, but may be attached to the front wheel side. Moreover, you may make it attach to both a front wheel and a rear wheel. Moreover, in the said Example, although described about the invention applied to the electrically assisted trolley | bogie using at least a pair of left and right wheels, it was used for a one-wheeled vehicle having one wheel, a three-wheeled vehicle having three wheels, or the like. It is also useful as a driving means for electric assist for forward, backward, and turning.

  In the above example, the plate members 33L and R as deformation recovery members are interposed between the handle operating unit 30 and the carriage unit. However, any other arbitrary one can be used as long as the user can detect the force applied to the carriage unit. It may be interposed at the position of. For example, a deformable member can be interposed between the wheel and the handle operating unit 30 at a location where stress is applied in the vicinity of the wheel.

  Furthermore, although one plate member 33L, R is provided on each of the left and right sides, the present invention is not limited to this, and deformation recovery caused by operations on the electric assist cart, for example, forward, reverse, and left / right turning operations. One plate member or three or more plate members can be used as long as the difference in deformation of the sex members can be distinguished from each other. The same applies to the arrangement and number of strain gauge sensors attached to the plate member. For example, the deformation recovery member may be configured as a single plate member extending in the width direction of the handle, and the strain detection means may be attached in the vicinity of the left and right ends of the plate member.

  In the above embodiment, the cart is controlled to turn by different speed control of the left and right electric assist drive means 10L, R. For example, an electric turning mechanism (not shown) for electrically turning the rear wheel or the front wheel to the left and right. ) Can be turned.

  In addition, although a strain gauge sensor is taken as an example of the strain detection means, the present invention is not limited to this, and any sensor, for example, a position, may be used as long as the sensor is configured to detect the deformation of the deformable member. A sensor, a stress sensor, a piezoelectric resistance sensor, an electric resistance sensor, or the like can be used.

  Furthermore, the present invention can also be applied to a rear car type carriage in which the handle operation unit 30 is attached to the front rather than the rear of the carriage unit 5.

FIG. 1 is a diagram of an electric assist cart according to an embodiment of the present invention, wherein (a) is a rear view of the electric assist cart, and (b) is a side view thereof. FIG. 2 is a top view and a side view of the handle operating portion of the electric assist cart of FIG. 1 showing the mounting position of the strain gauge sensor. FIG. 3 is a schematic diagram showing a control system of the electric assist cart of FIG. FIG. 4 is a flowchart showing a flow of control of the electric assist cart of FIG.

Explanation of symbols

1 Electric assist cart
5 Carriage part 6 Lower dumbbell carrier 8 Upper dumbbell carrier 10L, R Left and right electric assist drive means 12L, R Left and right motor gear 13 Battery bracket 14 Microcomputer 15L, R Amplifier circuit 16L, L Left and right chain 17 Battery 18L, R Left and right wheel gear 20L, R Left and right pair of rear wheels 24, 25 Ridge 26, 28 Dumbbell 30 Handle operation part 31 Grip bar 32L, R Left and right support bar 33L, L Left and right plate members 33L, R
35L, R Left and right cart bars 36L, R Left and right strain gauge sensors 37L, R A pair of left and right motors

Claims (19)

An electric assist cart having at least a pair of left and right wheels,
Left and right drive means respectively provided to provide auxiliary power to the pair of left and right wheels;
Left and right deformation recovery members interposed between the carriage part or the wheel and the handle operation part,
Left and right strain detection means attached to each of the left and right deformation recovery members;
Control means for individually controlling the left and right drive means according to the output signals of the left and right distortion detection means;
An electrically assisted trolley.   2. The electric motor according to claim 1, wherein when the difference between the output signals of the left and right distortion detection means is within a predetermined range, the control means controls the rotation speeds of the left and right drive means to be the same. Assist cart.   The electric assist cart according to claim 2, wherein the control means controls the rotational speeds of the left and right drive means to be different when a difference between output signals of the left and right distortion detection means exceeds a predetermined range. .   The control means may determine which of a rotation direction to advance the electric assist cart and a rotation direction to reverse the electric assist cart depending on whether each of the output signals of the left and right distortion detection means indicates pushing or pulling of the deformation recoverable member. The electric assist cart according to any one of claims 1 to 3, wherein the left and right drive means are individually controlled. A front wheel,
The electric assist cart according to any one of claims 1 to 4, wherein the handle operating portion is attached to the rear of the cart portion, and the pair of left and right wheels are rear wheels.
An electrically assisted cart having at least one wheel,
At least one drive means provided to provide auxiliary power to the wheels;
At least one deformation recovering member interposed between the carriage part or the wheel and the handle operating part;
At least one strain detecting means for detecting strain of the deformable member;
Control means for controlling the drive means according to the distortion of the deformation recoverable member detected by the distortion detection means;
An electrically assisted trolley.   The electric assist cart according to claim 6, wherein the control means performs forward control and reverse control of the drive means according to whether the deformation of the deformation recoverable member indicates forward or reverse operation with respect to the electric assist cart. A turning drive means for turning or bending the at least one wheel left and right;
The electric assist cart according to claim 6 or 7, wherein the control means controls the turning drive means according to whether the distortion of the deformation recovering member indicates a left or right turning or bending operation with respect to the electric assist cart. At least one wheel is provided on each of the left and right sides,
The drive means is provided to give auxiliary power to each of the left and right wheels,
The control means controls the driving means so that the left and right rotational speeds differ according to whether the deformation of the deformation recovering member indicates a left or right turning or bending operation with respect to the electric assist cart. The electric assist cart according to any one of the above.   The control means controls the drive means so that the left and right rotational speeds are the same when the distortion of the deformation recovering member indicating the turning or bending operation is within a predetermined range. The electric assist cart as described.   The said control means is controlled so that each rotational speed of the said drive means differs when distortion of the said deformation | transformation recoverable member which shows the said turning or bending operation | movement exceeds a predetermined range. Electric assist cart.   The rotational speed of the driving means is determined based on the magnitude of the output signal of the distortion detecting means, and the rotational direction of the driving means is determined based on the sign of the output signal of the distortion detecting means. The electric assist cart according to 1 or 6.   The electric assist cart according to any one of claims 6 to 12, wherein the number of wheels is one, and the electric assist cart is configured as a cart of a unicycle.     The electric assist cart according to any one of claims 6 to 12, wherein the number of wheels is three, and the electric assist cart is configured as a tricycle cart.   The electric assist cart according to any one of claims 1 to 14, wherein the deformation recovering member is deformed by at least one of expansion / contraction deformation, warping / bending deformation, and uneven deformation.   The electric assist cart according to any one of claims 1 to 15, wherein the deformation recovery member is one of a spring member, an elastic member, a plate member, and a metal plate.   The electric assist cart according to any one of claims 1 to 16, wherein the strain detection means is any one of a strain gauge sensor, a position sensor, a stress sensor, a piezoelectric resistance sensor, and an electric resistance sensor. The driving means includes
A motor,
A motor gear for transmitting the output of the motor;
A wheel gear mounted to rotate coaxially with the wheel;
Drive transmission means provided between the motor gear and the wheel gear;
The electric assist cart according to claim 1, comprising:   The electric assist cart according to claim 18, wherein the drive transmission means is at least one of a chain, a belt, and a gear.

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