JPH11164854A - Running control device of motor-assisted wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a running control device of a motor-assisted wheelchair which enables a user of the wheelchair to drive it rhythmically and nearly at a constant pitch even if the road condition changes. SOLUTION: An inertia running speed reduction detecting part 138 detects that the wheelchair is running forward by signals outputted from a rotation direction detecting switch 10, and calculates a speed reduction while the wheelchair is running by inertia based on the data from a speed detector 11. And a torque converting table 124, receiving data on the speed reduction from the inertial running speed reduction detecting part 138, outputs a larger torque instruction when the speed reduction is large, and a smaller torque instruction when the speed reduction is small, so that the timing when the speed becomes a prescribed one during inertial running is the same or almost the same without regard to the sloping angle of the road where the wheelchair is running. So a user of the wheelchair can the wheelchair rhythmically and almost at a constant pitch as the user starts driving when the speed of the wheelchair running by inertia becomes a prescribed one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving control device for an electric assist (wheel assist) wheelchair, and more particularly, to an electric assist that can be driven at almost the same pitch even when traveling uphill, on flat ground, and on downhill. The present invention relates to a travel control device for an electric assist wheelchair.

[0002]

2. Description of the Related Art Conventionally, an electric assist wheelchair has been developed as an assist device for a person who has difficulty walking. This electric assist wheelchair detects the human power intermittently applied to the wheels via the hand rim, and adds an auxiliary power corresponding to the human power to the wheels, thereby reducing the force of the rider turning the hand rim.

One of the prior arts of this type of electric assist wheelchair is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-168506. In this prior art, a driving motor as an auxiliary power unit transmits its driving force to wheels via four gears. Then, when it is detected that human power has been applied to the wheels, the auxiliary power corresponding to the human power is added to the wheels, and even after the human power is no longer detected, the auxiliary power remains and the electric power The coasting distance of the wheelchair is made longer. As a result, the rider can increase the pitch of the wheels, and the burden on the rider can be reduced.

[0004]

However, in the prior art, the driving motor is directly connected to wheels via four gears, and the driving of the electric assist wheelchair is controlled by an electric command. However, no special consideration was given to the rider's pitch. For this reason, there is a problem that the pitch changes according to the road surface on which the vehicle travels, and in particular, when climbing a hill, the pitch is shortened and a burden is imposed on the rider.

For example, as shown in FIG. 12 (a), assuming that the vehicle speed q is obtained from the time t0 to t1 by the action of the electric assist force with respect to the input torque p, the time t1
The vehicle speed q during the subsequent coasting period changes to vehicle speeds q1 to q3, respectively, depending on whether the road surface on which the wheelchair is traveling is uphill, flat ground, or downhill. Generally, the rider rides the wheelchair when the wheelchair is decelerated to a predetermined speed (r in the figure),
When the traveling road surface is flat, the rider climbs at time t3, while when climbing, the rider climbs at time t2 (t2 <t3).
4 (t4> t3). Therefore, the pitch at which the wheelchair is sunk when traveling on level ground is (t3-t0)
On the other hand, when traveling uphill, the distance becomes (t2-t0) and becomes shorter, and when traveling downhill, the distance becomes (t4-t0) and becomes longer.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to maintain the same pitch even when the road surface condition changes.
An object of the present invention is to provide a driving control device for an electric assist wheelchair which can be rhythmically driven.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an electric assist wheelchair traveling control apparatus which advances by adding an electric assist force to an intermittently applied human power. The first characteristic is that the vehicle speed reduction detecting means for detecting the decrease in the vehicle speed and the electric power assisting force changing means for changing the electric power assisting power according to the value detected by the vehicle speed reduction detecting means. Further, by performing the electric assist control according to the torque command value output from the electric assist force changing means, the timing at which the predetermined speed is reached during coasting can be achieved without depending on the inclination angle of the traveling road. A second feature lies in that they are simultaneously or almost simultaneously.

According to the first feature, the electric assist force is changed in accordance with the decrease in the vehicle speed during coasting, so that the timing at which the rider rides in a wheelchair can be adjusted according to the state of the traveling road. Further, according to the second feature, the timing at which the rider rides a wheelchair is substantially constant regardless of whether the traveling path is uphill, flatland, or downhill, and rhythmically rides without depending on the state of the traveling path. Will be able to do it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a side view of an electric assist wheelchair according to an embodiment of the present invention, FIG. 2 is a rear view taken along line 2-2 of FIG.
FIG. 3 is an enlarged cross-sectional view of a main part when cut along a plane passing through each longitudinal direction of the axle and the drive shaft of the electric motor in FIG.

First, a schematic configuration of an electric assist wheelchair according to an embodiment of the present invention will be described. In FIG. 1, a body frame 14 of the electric assist wheelchair includes a pair of left and right upper frames 16 and a lower frame 17, and a seat 15 is supported by the upper frame 16. A rear wheel WR disposed on each of the left and right sides of the seat 15 and a pair of left and right front wheels WF disposed in front of the two rear wheels WR are connected to both lower frames 1.
7 supported.

The upper frame 16 has a handrail 18a at the top.
A side frame 18 that is formed continuously on the left and right sides of the seat 15;
And cross members 19 and 20 erected between the side frames 18 below the seat portion 15a to support two places spaced apart in front of and behind the seat portion 15a.
Backrest 1 to support the backrest 15b at
5b, and a cross member 21 erected between both side frames 18 at the rear of 5b.

The lower frame 17 extends in the front-rear direction at positions spaced below the upper frame 16, and includes a front wheel support 22, a rear wheel support 23, and front and rear wheel supports 22, 23. A pair of upper and lower pipe-like frame members 24 and 25 for connecting between the two frame members.
The middle portion of each of 4, 25 is formed to be curved downward.

At the front end of the front wheel support portion 22, there is integrally provided a support tube 22a that is slightly inclined rearward as it goes upward, and a support rod 26 that penetrates the support tube 22a is positioned at its height. Is adjustable and fixedly supported by the support cylinder 22a. Support rods 26 respectively supported by the front end support cylinders 22a of the left and right lower frames 17
A step 27 is provided between the lower ends of the steps. A cross member 28 is provided between the rear portions of the front wheel support portions 22.

The front wheel WF is a caster, and is supported at the lower end of a support member 30 having a front wheel shaft 29 extending vertically, the front wheel shaft 29 being fixed to an intermediate portion of the front wheel support portion 22 in the front-rear direction. At 31 it is rotatably supported.

2 and 3, the rear wheel WR includes a wheel hub 32 formed in a ring shape and a plurality of wheels extending radially from a plurality of circumferentially spaced portions of the wheel hub 32. , A rim 34 provided at the outer end of each spoke, and a tire 35 mounted on the rim 34.

Lower frame 17 of body frame 14
A cover 36 that covers the inside end of the wheel hub 32 and one end of an axle 37 that is coaxial with the rear wheel WR are detachably fixed to the rear wheel support portion 23.
Extends outward through the cover 36 and the wheel hub 32. An electric motor 38 having a rotation axis is fastened to the cover 36 at a position shifted from the axis of the axle 37.

The wheel hub 32 has the same axis as the axle 37 and has a cylindrical first hub half 39 whose diameter decreases toward the outside, and a sleeve 40a coaxially surrounding the axle 37. And a second hub half 40 which is bolted to an axially outer end of the first hub half 39, and a half of each spoke 33 is connected to the first hub half 39, The other half of the spoke 33 is the second
It is connected to the hub half 40. Moreover, on the outer peripheral edge of the cover 36, a spring is formed on the inner surface of the inner end portion of the first hub half 39 in the wheel hub 32 in order to prevent dust from entering the storage chamber 41 surrounded by the cover 36 and the wheel hub 32. An annular seal member 42 that comes into sliding contact is mounted.

A hand rim hub 43 is disposed coaxially with the axis of the axle 37 outside the wheel hub 32 in the axial direction. A hand rim 45 having a ring shape is provided.

A ring 46 coaxial with the axle 37 has a plurality of bolts 47 on the inner side in the axial direction of the hand rim hub 43.
The ring body 46 is inserted into the axial end of the wheel hub 32. Moreover, the ring body 46
A first seal bearing 48 provided with a seal member 48a between an inner ring and an outer ring is provided between the inner periphery of the axle 37 and the outer periphery of the axle 37.
_1, and the bearing 48 ₂ not having the sealing material is arranged by arranging a first seal bearing 48 ₁ axially outward. Further, the wheel hub 32 along the axial direction of the axle 37
A second seal bearing 49 provided with a seal material 49a between the inner ring and the outer ring is provided between the outer periphery of the outer end of the second hub half 40, that is, the outer periphery of the ring body 46 and the outer periphery of the ring body 46. Can be Furthermore, in the storage room 41, the cover 3
A support plate 50 as a support member is fastened to the inner surface side of 6, and a bearing 51 is provided between the support plate 50 and the inner end of the wheel hub 32 in the axial direction, that is, the outer periphery of the inner end of the sleeve 40 a. Provided. That is, the wheel hub 3
2 is rotatably supported on a support plate 50 fixed to the vehicle body frame 14, the wheel hub 32 is rotatable around the axis of the axle 37, and the hand rim hub 43 is It is rotatable around the axis of the axle 37 by allowing relative rotation with the hub 32.

A drive shaft 52 connected to the transmission motor 38 protrudes into the storage chamber 41. The driving force of the electric motor 38 is transmitted to the drive shaft via a planetary roller speed reducer 110 and a one-way clutch (one-way clutch) 111. The transmission mechanism 60 provided between the drive shaft 52 and the wheel hub 32 is stored in the storage chamber 41. The transmission mechanism 60 is coupled to a drive gear 53 fixed to a drive shaft 52 and a sleeve 40 a of the wheel hub 32 via a spline 55.
And the driven gear 54 that meshes with the wheel hub 32, that is, the power of the electric motor 38 can be applied to the wheel hub 32, that is, the rear wheel WR via the transmission mechanism 60.

The one-way clutch 111 is connected when the rotation speed of the input shaft of the one-way clutch 111 is higher than the rotation speed of the output shaft, and enters the power transmission state. Conversely, when the rotation speed of the input shaft of the one-way clutch 111 is smaller than the rotation speed of the output shaft, the one-way clutch 111 is separated and enters a power non-transmission state.

Further, in the central portion exterior surface of Handorimuhabu 43, the ring body 46 and the first seal bearing provided between the axle 37 48 ₁ and 48 ₂ is disengaged axially outward of the axle 37 A concave portion 57 is provided to face a nut 56 screwed to the outer end of the axle 37 to prevent the outer end of the axle 37 and the cap 58 that resiliently engages with the nut 56 to cover the outer end of the axle 37 and the nut 56. , Is fitted into the opening end of the recess 57.

Hand rim hub 43 and wheel hub 3
Numeral 2 is connected via a power transmission member 61 for transmitting the rotation torque input to the hand rim hub 43 to the wheel hub 32 while elastically deforming the rotation torque input to the hand rim hub 43 in response to the rotation operation of the hand rim 45 by input. This power transmission member 61
Are formed in a C-shape in a plane orthogonal to the axis of the axle 37, and the second of the hand rim hub 43 and the wheel hub 32
The power transmission member 61 is arranged in the space between the hub halves 40 so as to surround the ring body 46, and one end of the power transmission member 61 is connected to the hand rim hub 43 by a connection pin pressed into the hand rim hub 43. Member 61
Is connected to the second hub half 40 of the wheel hub 32 by bolts 63. Moreover, the hand rim hub 43
An annular groove 67 centered on the axis of the axle 37 is provided on the surface facing the wheel hub 32 of the vehicle, and the power transmission member 61 is accommodated and arranged in the groove 67.

In the storage chamber 41, a slip ring 68 is provided.
And an inner cover 69 arranged so as to cover the inner side of the slip ring 68 along the axial direction of the axle 37, and an inner cover 69 arranged so as to cover the outer side of the slip ring 68 along the axial direction of the axle 37. The outer cover 70 is stored.

The slip ring 68 includes a plurality of bolts 71
As a result, the wheel hub 32 is fixed to the inner surface of the outer end of the first hub half 39, and rotates integrally with the wheel hub 32. Although a detailed structure of the slip ring 68 is not described, an electrical signal indicating the number of rotations of the wheel hub 32 is obtained from the slip ring 68. Thereby, the traveling speed of the electric assist wheelchair can be detected.

The first and second seal bearings 48 ₁ , 49 of the ring body 46 fastened to the hand rim hub 43.
A connecting member 88 is fixed to the space, that is, to the inner end in the axial direction of the ring body 46 by a bolt 89 at two places spaced apart in the circumferential direction of the ring body 46. The connecting member 88 is connected to the sleeve 40 of the second hub half 40 of the wheel hub 32.
a is fixed to the ring body 46 by a bolt 89 in a through hole 90 provided in the storage chamber 41, and the through hole 90 is formed in the wheel hub 32, that is, the sleeve 40a, and the hand rim hub 43. That is, the arm 88 is formed to a size that allows the relative angle variation of the arm 88.

On the other surface of the slip ring 68, the wheel hub 3 corresponding to the torque input to the hand rim hub 43 is provided.
2, the slip ring 68 and the hand rim hub 43
That is, the phase difference detecting means 94 for detecting the relative angular displacement with respect to the outer cover 70 is provided. Hand rim hub 4
When a relative angular displacement occurs between the slip ring 68 and the outer cover 70 in accordance with the torque input to the motor 3, an electric output corresponding to the input torque is output from a torque detection terminal (not shown) of the phase difference detection means 94. You.

The traveling direction of the wheelchair, ie, the rear wheel WR
Is determined by the rotation direction determination means 103. The rotation direction discriminating means 103 includes a rotation direction detection switch 104 fixedly disposed on the support plate 50 and a driven gear 54 that rotates following the driven gear 54 by frictional contact when the driven gear 54 rotates. The pressing portion 105a of the flicking spring mounted on the annular groove 54a provided on the outer periphery of the base of the flap 54, and the regulating pin 106 for regulating the rotation range of the flicking spring driven by the driven gear 54.
It is composed of When the rear wheel WR rotates in the reverse direction, the pressing portion 105a of the flickion spring does not press the rotation direction detection switch 104. Conversely, when the rear wheel WR rotates in the forward direction, the pressing portion 105a of the flickion spring does not. Since the rotation direction detection switch 104 is pressed, whether the rear wheel WR is moving forward or backward is determined by turning on or off the rotation direction detection switch 104.

FIG. 4 shows an example of the structure of the electric motor 38. A plurality of fixed magnets 202 are fixed to a motor case 201, a motor shaft 203, and are fixed to the motor shaft 203 together. It is composed of a rotating coil 204, a power source (battery) and a brush 205 for electrically connecting the coil 204, and is attached to an attachment base 210. 206 and 207 are bearings;
Denotes an engagement portion with the planetary roller 110. As we all know,
When a current flows from the power supply to the coil 204 via the brush 205, a force is generated between the fixed magnet 202 and the coil 204, the motor shaft 203 rotates, and the rotating power is transmitted through the engaging portion 208. And transmitted to the planetary roller 110.

FIG. 5 is a simplified diagram showing the structure of the skeleton of the power transmission mechanism and the control unit of the electric assist wheelchair having the above-described structure so that the following description can be easily understood. In the figure, 1 is a battery, 2 is a bidirectional control device, 3 is a motor, 4 is a primary reducer, 5 is a one-way clutch, 6 is a secondary reducer, 7 is a driving wheel (rear wheel), 7a is a tire, 8 Is a two-way torque sensor, and 9 is a hand rim. Also, 1
0 is a rotation direction detection switch, 11 is a speed detector, and 12 is a control device (CPU). Here, the primary reduction gear 4
Corresponds to the planetary roller speed reducer 110, and corresponds to the secondary speed reducer 6
Corresponds to a transmission mechanism 60 including a driving gear 53 and a driven gear 54 meshing with the driving gear 53, and the speed detector 11 corresponds to a slip ring 68. In addition, the bidirectional torque sensor 8
Includes a power transmission member 61 having a C-shape, a phase difference detecting means 94, and the like.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 6 shows the control device (CP
FIG. 2 is a block diagram showing functions of U) 12 and the configuration of peripheral devices thereof.

Since the bidirectional torque sensor 8 detects the torque even when the hand rim 45 is rotated in both the forward and reverse directions, it is necessary to detect the actual torque value when the hand rim 45 is rotated in both the forward and reverse directions. Needs to determine the torque center value of the two-way torque sensor 8. Means for obtaining the torque center value are the center value learning unit 120 and the E ² PROM 121. Bidirectional torque sensor 8
The center value learning unit 120 stores the detected torque value received from the ^two- way torque sensor 8 in the E ² PROM 121 because the two-way torque sensor 8 is the detected torque value indicated for the longest time. Meanwhile, the torque center value is determined based on the past detected torque value data. Then, if a change occurs in the determined torque center value, it is updated. The latest torque center value is held in the center value holding unit 122, and the comparison unit 123 compares the torque value input from the bidirectional torque sensor 8 with the torque center value, and outputs the difference. As a result, the comparison unit 1
23 outputs an actual torque value a (hereinafter simply referred to as torque) a in either the forward or reverse rotation direction.

The torque a output from the comparison unit 113 is
Torque conversion table 124 and fail-safe control unit 1
Enter 37. The torque conversion table 124 has the characteristics shown in FIG. 7, and amplifies the input torque a to the magnitude (torque command value) shown by the curve b and outputs it. In FIG. 7, the torque command value b indicates the largest amplification factor at the center of the input torque a, but is not limited to this.
The torque command value output from the torque conversion table 124 is input to the waveform control unit 125, and is subjected to waveform control, for example, as shown in FIG.

That is, assuming that the torque command value b1 having the magnitude shown at time t0 to t1 in FIG. 8 is input to the waveform control unit 125, the waveform control unit 125 converts the torque command value b1 into the torque d1 of the waveform d1. Convert to command value and output. At time t1, the torque command value b1 input to the waveform control unit 125 drops to 0, but the waveform control unit 12
5 does not follow this waveform, but outputs a torque command value of waveform d2.

This means that when the rider of the electric assist wheelchair moves forward and pushes the hand rim 45 in the forward direction with full force, the torque obtained at this time has a waveform indicated by b1. , The waveform output from the waveform control unit 115 is d1 + d2. In addition,
The period from time t1 to t2 indicates a period in which the rider has separated his / her hand from the hand rim 45, that is, a coasting period.

More specifically, in the present embodiment, with regard to the waveform d2 during the coasting period, electric assist (assist) is not performed when coasting on flat ground, but for example, when the climbing angle is 2 degrees.
When the angle exceeds °, the waveform is made so that the electric assist is activated. That is, as shown in FIG. 9, suppose that the speed curve of the wheelchair when the electric assist wheelchair is swung on level ground becomes (s1 + s2), and s2 is the coasting period (t1 to t1).
Assuming that the speed is t8), during the coasting period,
The waveform d2 is set so that the rotation speed of the input shaft of the one-way clutch 5 is smaller than the rotation speed of the output shaft (input shaft rotation speed <rotation speed of the output shaft), and the one-way clutch 5 is disconnected. To be. On the other hand, for example, if the speed curve of the wheelchair when the electric assist wheelchair is swung uphill at an angle of 2 ° is (r1 + r2), and r2 is the speed during the coasting period (t1 to t7), In the coasting period, the waveform d2 is set so that the rotation speed of the input shaft of the one-way clutch 5 is substantially equal to the rotation speed of the output shaft, so that the one-way clutch 5 is brought into a state of starting connection. .

As a result, the electric assist wheelchair is moved from level to angle 2
When coasting while traveling on a road surface during an uphill of 0 °, the electric assist does not operate, but when coasting while traveling uphill with an angle of 2 ° or more, the electric assist operates.
For this reason, when the electric assist wheelchair is traveling on a road surface between a flat ground and an angle climb of 2 °, the rider gives the rider a natural coasting feeling in which the electric assist does not work. When it is, it becomes possible to extend the coasting distance with electric assistance.

Next, at time t2 in FIG. 8, if the rider turns the hand rim 45 in the reverse direction to stop the wheelchair, the torque of the waveform b2 is input to the waveform controller 125. The waveform control unit 125 outputs a zero waveform during the time when torque is generated to stop the wheelchair and the time from when the wheelchair is stopped t2 to t4. The determination that the rider has tried to stop the wheelchair is made based on the fact that the reverse torque is generated when the signal e from the rotation direction detection switch 10 is positive. If a reverse torque is generated when the signal e from the rotation direction detection switch 10 is 0 or reverse, it is determined that the vehicle is moving backward (back).

Next, at time t4, if the hand rim 45 is turned in the reverse direction to move the rider backward, the torque of the waveform b3 is input to the waveform control unit 125. At this time, the waveform controller 125 outputs the torque command value of the waveform d3. This is because the one-way clutch 5 is used in the present embodiment to transmit the driving force generated by the motor 3 to the driving wheels 7 (see FIG. 5). As is well known, the one-way clutch 5 is not connected when the rotation speed of the input shaft is smaller than the rotation speed of the output shaft.
If the driving wheels 7 are rotated in reverse while the motor 3 is stopped, the rotation speed of the output shaft is negative (minus) with respect to the rotation speed of the input shaft.
And the input shaft speed> output shaft speed.
Even though the motor 3 is stopped, the input shaft and the output shaft are connected. Therefore, as described above, when the hand rim 45 is rotated in the reverse direction in order to move the rider backward, the hand 3 is rotated along with the motor 3 and the load for rotating the hand rim 45 in the reverse direction increases.

In this embodiment, in order to solve this problem, when the rider turns the hand rim 45 in the reverse direction in order to move backward, the motor 3 is positively rotated in the reverse direction and the input shaft is rotated. The condition of rotation speed> output shaft rotation speed is not satisfied. As a result, the motor 3 does not rotate, and the rider can reversely rotate the hand rim 45 with a small load. During the period from time t5 to time t6, a negative torque command value of waveform d3 is output even though the torque of waveform b2 is zero. Sometimes, motor 3
This is to enable natural coasting without turning around. It is preferable that the waveform d3 is such that, for example, the drive signal of the motor 3 has a duty of about 20% (fixed).

The torque command value d generated by the waveform control unit 125 shown in FIG.
To enter. The rotation direction signal generation unit 126 outputs a signal f indicating the rotation direction of the motor 3 shown in FIG. 10 based on the torque command value d and the rotation direction e obtained from the rotation direction detection switch 10, , And off signals g and h. That is, when the torque command value d is negative and the rotation direction e is reverse, the output signal f of the rotation direction signal generator 126 is reversed, the signal g is on, and the signal h is off. On the other hand, when the torque command value d is positive and the rotation direction e is positive, the output signal f of the rotation direction signal generator 126 is forward rotation, the signal h is on, and the signal g is off. In other cases, the output signal f of the rotation direction signal generator 126 may be either forward or reverse (free), and both the signals g and h are off. In addition,
For the output signals g and h, ON indicates a logic 1 and OFF indicates a logic 0.

The drive circuit 200 of the motor 3 to which the signals f, g, h are inputted is connected to the motor 3 as shown in the figure.
Switching means (for example, FE)
T) 201, 202, a switch 203 for determining the rotation direction of the motor 3, and a current sensor 204. The output signal f controls the switching of the switch 203 that determines the rotation direction of the motor 3, and the output signals g and h are input to the FETs 201 and 202 to control on and off thereof. The current detector of the current sensor 204 is equivalent to the torque.

The motor current detected by the current sensor 204 is input to the A / D converter 130, converted into a digital signal, and input to the averaging unit 131. The averaging unit 131 calculates an average value of the motor current and outputs the average value to the current value calculation unit 132. On the other hand, the current sensor 0 point detection unit 133 determines the average value of the motor current when the duty, which is the output of the duty output unit 134, is 0 as the 0 point of the current sensor 204. The current value calculation unit 132 subtracts the current value of the zero point from the average value of the motor current to obtain an actual motor current value.
27.

As described above, since the torque command value d created by the waveform controller 125 is input to the comparator 127, the comparator 127 determines the magnitude of the torque command value d and the motor current value. And outputs a positive signal if the former is larger than the latter, 0 if they are equal, and a negative signal if smaller. When receiving the positive signal, the duty output unit 134 increases the duty, for example, by 0.2%. When a signal of 0 is received, the duty at that time is maintained, and when a negative signal is received, for example, the duty is reduced by 0.2%. Also,
The duty output unit 134 forcibly sets the duty to 0 when receiving, for example, data at a vehicle speed of 6 km / h or more from the speed detector 11. In other words, the wheelchair speed is 6
When the vehicle speed exceeds km / h, the electric assist is stopped.

Output i from duty output section 134 is A
The ND gates 135 and 136 are input to the ND gates 135 and 136, and the output of the FET 2
01, 202. For example, when the output signal g is on, it is applied to the FET 201, and when the output signal h is on, it is applied to the FET 202.

Therefore, during the period from time t0 to time t2 in FIG.
(= D1 + d2) is positive, and the rotation direction e obtained from the rotation direction detection switch 10 is positive. Therefore, as is apparent from FIG.
The ET 201 turns off and the 202 turns on. Therefore,
The motor 3 performs a normal rotation operation according to the waveform of the torque command value (d1 + d2).

On the other hand, during the period from time t4 to time t6 in FIG.
(= D3) is negative, for example, a duty (fixed) of 20%, and the rotation direction e obtained from the rotation direction detection switch 10 is opposite. Therefore, as is apparent from FIG. 10, the switch 203 is connected to the reverse terminal. Then, the FET 201 is turned on and the FET 202 is turned off. As a result, the motor 3 performs a reverse rotation operation according to the waveform of the torque command value d3.

In the period from time t2 to time t3 in FIG. 8, the torque command value d output from the waveform control section 125 is 0, and the rotation direction e obtained from the rotation direction detection switch 10 is 0.
Is positive, and as is apparent from FIG.
02 are both turned off, and the rotation of the motor 3 stops.

Next, by adding a coasting vehicle speed reduction amount detection section 138 shown by a dotted line to FIG. 6 and making the characteristics of the torque conversion table 124 as shown in FIG. 10, even if the road surface condition changes. In other words, even if the road surface goes uphill, flatland, or downhill, it is possible to ride rhythmically at almost the same pitch. The configuration and operation of this function will be described below.

In the characteristic shown in FIG. 11, the torque command value b
When the vehicle speed decrease amount during coasting is higher than the first predetermined value when climbing a hill or traveling on a rough road, the input torque 1 is increased as indicated by the characteristic b1.
When the amount of decrease in vehicle speed during coasting is equal to or less than the first predetermined value and equal to or greater than the second predetermined value, the torque command value becomes 2 with respect to the input torque 1 as indicated by the characteristic b2. When the vehicle speed decrease amount during coasting is equal to or less than the second predetermined value, for example, during a downhill, a torque command value having a magnitude of 0.5 with respect to the input torque 1 as shown by the characteristic b3 is obtained. Become.

The selection of the characteristics b1, b2, b3 is controlled by the output of the vehicle speed reduction amount detecting unit 138 during coasting. That is, the vehicle speed reduction amount detection unit 138 detects that the vehicle is moving forward based on the signal from the rotation direction detection switch 10, and obtains the vehicle speed reduction amount during coasting from the speed detector 11. When the torque conversion table 124 obtains the vehicle speed reduction amount from the coasting vehicle speed reduction amount detection unit 138, the characteristics b1, b2, and b3 are selected according to the vehicle speed reduction amount. In the illustrated example, the characteristic of the torque command value is divided into three stages of large, medium, and small vehicle speed reduction amounts. However, the present invention is not limited to this, and may be further divided into multiple stages.

When the torque command value output from the torque conversion table 124 is input to the waveform control unit 125, the waveform of the torque command value is controlled, for example, as shown in FIG. That is, assuming that the torque command values b1, b2, b3 having the magnitudes shown at times t2 to t3 in FIG.
5 shows the torque command values b1, b2, b3 as waveforms d1, d2.
, D3 and output. These waveforms d1, d2 and d3 are used to convert the torque command values b1, b2 and b3 input to the waveform control unit 125 into a predetermined waveform.
, D2 and d3.

Here, the technical significance of the waveforms d1, d2 and d3 will be described in detail with reference to FIG.
Assuming that the first stroke is performed in the period from time t0 to time t1 in FIG.
From time t2 to time t2, the signal from the rotation direction detection switch 10 and the torque from the comparison unit 123 are almost 0, thereby detecting that the vehicle is traveling forward and coasting, respectively. The vehicle speed reduction amount is detected by capturing the speed data of the vehicle. Then, the vehicle speed reduction amount is sent to the torque conversion table 124. The torque conversion table 124 stores the characteristic b1 based on the received vehicle speed reduction amount.
, B2 or b3, and amplifies the input torque a.

The torque command value b amplified according to the characteristics selected in the torque conversion table 124
At step 25, the torque is controlled to the torque command values d1 to d3 having waveforms shown at times t2 to t3 in FIG. As a result, the vehicle travels uphill at the speed of waveform d1 when the road is uphill, travels with waveform d2 when the road is flat, and descends with waveform d3 when it is downhill.

At time t3, when the rider releases the hand rim 9 to start coasting, the speed of the wheelchair decreases as shown by waveforms e1, e2 and e3. At time t4, the velocity waveforms e1, e2 and e3 all become velocity r. As described above, when the speed of the wheelchair becomes r, the rider makes the next sweep, so that the timing of riding the hand rim 9 is almost the same regardless of whether the wheelchair travels on an uphill, on a flat ground, or on a downhill. Become. After time t4, the timing at which the hand rim 9 is slid is time t5, t6,..., So that the rider can squeeze the hand rim 9 at substantially the same pitch regardless of the state of the traveling path. Therefore, the rider can operate the hand rim 9 rhythmically.

In the above description, the detected value of the vehicle speed decrease amount during coasting detection unit 138 is input to the torque conversion table 124, but is input not to the torque conversion table 124 but to the waveform control unit 125, and the input torque p Alternatively, the waveforms d1 to d3 may be generated.

The fail-safe control section 137 receives the torque from the comparison section 123, the motor current value from the A / D conversion section 130, and the speed detection value from the speed detector 11 as inputs, and the electric assist device is normal. Check whether or not. For example, if the torque input from the comparison unit 123 is not longer than 30 minutes, it is determined that the power is continuously turned on even though the electric assist wheelchair is not used. That is, it is determined that the power has been forgotten to be turned off. If the torque fluctuation does not exceed 3 seconds, it is determined that the electric assist device may have a failure. Or A
If there is an abnormality in the current value input from the / D converter 130, the speed detection value from the speed detector 11, and the like, it is determined that the motor 3 or its driving circuit and the speed detector 11 may have a failure. When the fail-safe control unit 137 detects any abnormality, it outputs a control signal j to output the power supply circuit 210
Of the power supply to the control device 12 is stopped. The power supply circuit 210 includes a regulator.

When the main switch 211 is turned on, power is supplied from the power supply circuit 210 to the control device 12. When the fail safe control unit 137 determines that there is no abnormality, the transistor 212 is turned on by the control signal k, and the main relay 213 is turned on. Turns on. As a result, the power supply circuit 210
Then, the power supply is connected to the drive circuit of the motor 3 and the operation state is entered.

[0059]

As is apparent from the above description, according to the present invention, the electric assist force is changed in accordance with the decrease in the vehicle speed during coasting, so that the timing at which the rider takes a wheelchair is adjusted to the state of the traveling road. Can be adjusted accordingly. Also, regardless of whether the running path of the wheelchair is uphill, flatland, or downhill, the rider's wheelchair pitch is almost the same,
The rider can operate rhythmically irrespective of the state of the running path.

[Brief description of the drawings]

FIG. 1 is a side view of an electric assist wheelchair to which the present invention is applied.

FIG. 2 is a rear view taken along line 2-2 of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part when cut along a plane passing through each longitudinal direction of the axle and the drive shaft of the electric motor in FIG. 2;

FIG. 4 is a sectional view of a specific example of an electric motor.

FIG. 5 is a diagram showing a simplified configuration of a skeleton and a control unit of a power transmission mechanism of the electric assist wheelchair.

6 is a functional block diagram illustrating functions of a control device (CPU) in FIG.

FIG. 7 is a characteristic diagram of the torque conversion table of FIG. 6;

8 is a diagram illustrating an example of a control waveform generated by a waveform control unit in FIG.

FIG. 9 is a diagram illustrating an example of a control waveform during a coasting period.

FIG. 10 is a diagram illustrating a function of a rotation direction generation unit in FIG. 6;

FIG. 11 is a characteristic diagram of a torque conversion table according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating input / output torque waveforms of the waveform control unit according to the present embodiment.

FIG. 13 is a waveform diagram of the vehicle speed obtained by the conventional device and the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Battery, 2 ... Bidirectional control device, 3 ... Motor, 4 ...
Primary reduction gear, 5: one-way clutch, 6: secondary reduction gear, 7: drive wheel (rear wheel), 8: bidirectional torque sensor, 9
... hand rim, 10 ... rotation direction detection switch, 11 ... speed detector, 12 ... control device (CPU), 123 ... comparison unit, 124 ... torque conversion table, 125 ... waveform control unit, 126 ... rotation direction signal generation unit, 130 ... A / D converter, 131 ... averaging unit, 132 ... current value calculation unit, 133
... Current sensor 0 point detection unit, 134 ... Duty output unit
138: vehicle speed decrease amount detection section during coasting, 200: drive circuit,
204 ... current sensor.

Claims (3)

[Claims] 1. A traveling control device for an electric assist wheelchair that advances by adding an electric assist force to an intermittently applied human power, a vehicle speed decrease detecting means for detecting a decrease in vehicle speed during coasting, and a vehicle speed decrease detecting means. And a power assisting force changing means for changing the power assisting force in accordance with the value detected by the control device. 2. The traveling control device for an electric assist wheelchair according to claim 1, wherein the electric assist control according to the torque command value output from the electric assist force changing means is performed so as to be predetermined during coasting. A travel control device for an electric assist wheelchair, wherein timings at which the vehicle travels at a speed are simultaneously or almost simultaneously independent of the inclination angle of the travel path. 3. The travel control device for an electric assist wheelchair according to claim 1, further comprising a table of torque command value data determined in advance according to a vehicle speed reduction amount, and performing torque conversion using the table. A travel control device for an electric assist wheelchair, comprising: