JP3650315B2 - Control device for small electric vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a small electric vehicle used as an electric wheelchair or a golf cart, and more specifically, a control for reducing or suppressing a shock caused by a backlash of a reduction gear when the small electric vehicle starts. Relates to the device.
[0002]
[Prior art]
As the above-described small electric vehicle, a technique described in US Pat. No. 4,729,447 or JP-A-10-165454 is known. Furthermore, the technology described in Japanese Patent No. 2724565 prevents sudden start when starting from the time of stopping, makes it start smoothly, and the small electric vehicle slides down due to insufficient torque when climbing up. In this case, a control is proposed in which the output torque of the electric motor that drives the small electric vehicle is increased to smoothly perform the climbing operation.
[0003]
[Problems to be solved by the invention]
By the way, the drive system in this type of vehicle is usually composed of a combination of an electric motor and a reduction gear, and the output of the electric motor is transmitted to the wheels via the reduction gear, so that the backlash of the reduction gear is large. When a small electric car was started, there was a case where a shock was given to a passenger. In particular, when high-capacity electric motors are used with an emphasis on climbing performance, this becomes significant.
[0004]
However, the above-described prior art only proposes smooth start control and the like, and does not take any measures against a shock caused by a backlash of the reduction gear.
[0005]
Accordingly, an object of the present invention is to eliminate the above-described problem, and even when a large-capacity electric motor that emphasizes climbing performance is used, the shock at the start due to the backlash of the reduction gear is reduced or suppressed. It is another object of the present invention to provide a control device for a small electric vehicle that can start smoothly.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a control device for a small electric vehicle having an electric motor for driving a wheel via a reduction gear according to claim 1, wherein at least a setting speed is input. A speed switch, an accelerator lever for inputting start and stop instructions, and at least outputs of the set speed switch and the accelerator lever are input, a target speed is set according to the input, and the electric motor is set so as to be the set target speed The electric motor control means controls the applied voltage of the motor, and when the start instruction is issued from the stop state, the electric motor control means immediately applies the first predetermined voltage to the electric motor, and then the second predetermined voltage. After executing voltage control to increase the applied voltage at a predetermined rate until it reaches the voltage, the applied voltage is controlled to achieve the target speed. It was constructed as that.
[0007]
When a start instruction is issued from the stop state, the first predetermined voltage is immediately applied to the electric motor, and then voltage control is performed to increase the applied voltage at a predetermined increase rate until the second predetermined voltage is reached. That is, by applying a first predetermined voltage and rotating the electric motor by a small amount, the backlash of the reduction gear can be absorbed, and even when using a large-capacity electric motor that emphasizes climbing performance, It is possible to reduce or suppress the shock at the start due to the backlash of the reduction gear.
[0008]
Further, after executing voltage control for increasing the applied voltage at a predetermined increase rate until the second predetermined voltage is reached, the applied voltage is controlled to achieve the target speed, so that the vehicle can start smoothly. be able to.
[0009]
According to a second aspect of the present invention, the electric motor control means is configured to execute the voltage control even when a start instruction is input after a stop instruction is input.
[0010]
Since the voltage control is performed even when a start instruction is input after a stop instruction is input, shock caused by backlash of the reduction gear can be reduced or suppressed even in the reacceleration state. In addition, it is possible to smoothly shift to speed control (acceleration control).
[0011]
According to a third aspect of the present invention, the vehicle further includes a travel start determination unit that determines whether or not the travel is started, and the electric motor control unit stops the voltage control when it is determined that the travel is started. The applied voltage is controlled so as to immediately reach the target speed.
[0012]
When it is determined that the vehicle has started running, the voltage control is stopped, and the applied voltage is controlled so as to immediately reach the target speed. In this case, it is possible to travel in a desired direction while preventing further sliding down. In such a case, since the backlash of the reduction gear is normally minimized, the voltage control described above is essentially unnecessary.
[0013]
More specifically, the travel start determination unit includes a rotation direction detection unit that detects a rotation direction of the electric motor, and the electric motor control unit determines whether the detected rotation direction of the electric motor is the start instruction. When the rotation direction is reverse to the direction of travel, the applied voltage is controlled to immediately reach the target speed.
[0014]
When the detected rotation direction of the electric motor is opposite to the rotation direction for traveling in the direction instructed to start, the applied voltage is immediately controlled so as to reach the target speed. When the vehicle starts to climb in the uphill direction, if the occupant slips down (retreats) in an unintended direction, the vehicle can travel in a desired direction while preventing further slip-down (retreat).
[0015]
DETAILED DESCRIPTION OF THE INVENTION
A control apparatus for a small electric vehicle according to an embodiment of the present invention will be described below with reference to the accompanying drawings.
[0016]
1 is a plan view of a control device for the small electric vehicle, more specifically, a small electric vehicle storing the control device, FIG. 2 is a reduced side view thereof, FIG. 3 is a front view thereof, and FIG. FIG.
[0017]
As will be described below, the small electric vehicle 10 on which the control device according to the present invention is mounted has a scooter-like appearance including the main frame 12. A handle pipe 14 is attached to the front end of the main frame 12, and a steering wheel 16 is attached above the handle pipe 14.
[0018]
The handle pipe 14 is connected to the two front wheels 22 and 22 through the gear mechanism 18 at the other end, and steers the front wheel 22 in a direction and an angle according to the rotation of the steering wheel 16.
[0019]
A post 24 is erected on the rear end side of the main frame 12, and a seat 26 on which a passenger is seated is attached above the post 24. In addition, illustration of the sheet | seat was abbreviate | omitted in FIG. 3 and FIG.
[0020]
A (power generation) electric motor 28 is accommodated in the lower portion of the seat 26. The output of the electric motor 28 is transmitted to the accelerator 34 via the electromagnetic brake 30 and the reduction gear 32, and drives the two rear wheels 36, 36 attached to both ends thereof.
[0021]
The electric motor 28 is connected to two batteries (vehicle-mounted power supplies) 38 and 38 (each having a capacity of 12 V) housed in the vicinity of the handle pipe 14 on the front wheel side, and rotates by receiving battery voltage. As described above, the small electric vehicle 10 is configured as a four-wheel vehicle, and the battery is disposed between the front wheels to improve the stability. Reference numeral 40 denotes a main fuse box.
[0022]
Further, as shown in FIG. 3, a headlight 44 is provided on the front surface of the vehicle, and direction indicator blinker lights 46, 46 are provided on both side surfaces thereof. In addition, as shown in FIG. 4, two reflectors 48 are disposed at the rear of the vehicle.
[0023]
The electric motor 28 is controlled by a control unit (electronic control unit; electric motor control means) 50 disposed adjacent to the lower space of the seat 26 on the rear wheel side (reference numeral 50 indicates the control unit in more detail). The box to be accommodated is shown, but the control unit is indicated by reference numeral 50 for convenience of illustration). The control unit 50 includes a microcomputer.
[0024]
FIG. 5 is a circuit diagram showing details of the control unit 50. Although omitted in FIG. 5, the control unit 50 includes a motor drive circuit 54 as shown in FIG. 6. The motor drive circuit 54 includes a bridge circuit composed of four FETs (switching elements) A, B, C, and D.
[0025]
In FIG. 6, when two opposing FET elements A and D are turned on and a source current flows as shown by an arrow (solid line), the electric motor 28 rotates forward in the direction shown by the arrow (solid line) to make a small electric motor. The vehicle 10 is caused to travel in the forward direction.
[0026]
On the other hand, when the two opposing FET elements B and C are turned on and a source current flows as shown by an arrow (broken line), the electric motor 28 reverses in the direction shown by the arrow (broken line) to rotate the small electric vehicle 10. Drive backwards. Further, when the two FET elements C and D arranged in parallel are turned on, the coil is short-circuited.
[0027]
In a predetermined operating state, the electric motor 28 acts as a generator and charges the battery 38. The battery 38 can be charged from an external DC power source via the charger 56.
[0028]
A main control panel 58 is disposed in the vicinity of the steering wheel 16. FIG. 7 is an enlarged top view of the main control panel 58, and FIG. 8 is an explanatory view showing the display of the panel portion (indicated as “PANEL” in FIG. 5). Note that the steering wheel 16 is not shown in FIG.
[0029]
As shown in the figure, a rotary key switch 62 is provided below the main control panel 58. The key switch 62 is provided in the motor drive circuit 54 that connects the electric motor 28 to the battery 38.
[0030]
When the key switch 62 is turned to the “stop” position shown in FIG. 8 by the occupant, the connection between the battery 38 and the electric motor 28 is cut off, and when the key switch 62 is turned to the “running” position, the battery 38 is connected to the electric motor 28. To do.
[0031]
7 and FIG. 8 of the key switch 62 is provided with a forward / reverse selection switch 64 for the occupant to select “front” (forward travel) or “rear” (reverse travel).
[0032]
A speed volume (set speed switch) 66 is provided above the key switch 62. The speed volume 66 outputs the voltage Vsv according to the position turned by the occupant between the numbers 2 to 6. That is, as shown in FIG. 9, a value from around 0V to around 8V is output, and the set speed is set from 0 km / h to 6.5 km / h accordingly.
[0033]
Further, as shown in FIG. 7, an accelerator volume (accelerator lever) 68 is disposed at the right end of the main control panel 58. The accelerator volume 68 is configured such that its free end is movable in the vertical direction on the paper surface in FIG. 7 and is moved downward on the paper surface by an occupant to input a start or stop instruction.
[0034]
The control unit 50 inputs the outputs of the speed volume 66 and the accelerator volume 68, sets the target speed according to the set speed set by the speed volume 66 and the operation amount of the accelerator volume 66, and sets the target speed to the target speed. Then, speed control (acceleration / deceleration control) for controlling the voltage applied to the electric motor 28 via the motor drive circuit 54 is performed.
[0035]
In addition, a rotary encoder (shown as “ENCODER” in FIG. 5) is provided on the output shaft (not shown) of the electric motor 28. The vehicle start speed is determined through the motor rotation speed. Outputs a proportional signal.
[0036]
The rotary encoder 72 is composed of a magnet link having 24 sets of magnetic poles fixed to the output shaft and two Hall ICs (both not shown) arranged in the vicinity thereof. When the vehicle travels forward, FIG. A pulse composed of the A phase and the B phase is output at the timing shown in FIG. 10A, and when traveling backward, the pulse is output at the timing shown in FIG.
[0037]
The output of the rotary encoder 72 is input to the control unit 50, and the control unit 50 determines whether or not the small electric vehicle 10 has started traveling from the output and detects the traveling speed.
[0038]
Next, the operation of the control device of the small electric vehicle 10 will be described.
[0039]
FIG. 11 is a flowchart showing the operation, and the illustrated program is executed every predetermined time. FIGS. 12 to 14 are time charts showing a case where the vehicle is started from flat ground, a case where the vehicle is started from a slope, and a case where a start (acceleration) is instructed after a stop is instructed.
[0040]
Hereinafter, the description will be made with reference to the time charts of FIGS. 12 to 14. First, in S10, the output of the accelerator volume 68 or the like is read, and the process proceeds to S12, where the accelerator volume 68 is turned on (ON), that is, a start instruction is issued. Judge whether or not.
[0041]
When the result in S12 is affirmative, the program proceeds to S14, in which the accelerator volume 68 is turned off in the previous process, and it is determined whether speed control is being executed. That is, as shown in FIG. 12 and FIG. 13, the accelerator volume 68 is turned on again after the stop instruction is given as shown in FIG. 14, not when the small electric vehicle 10 receives a start instruction from the stop state. It is determined whether or not a start instruction, in other words, a reacceleration instruction is given.
[0042]
When the result in S14 is negative, the start is instructed from the stop state, so the process proceeds to S16, where it is determined whether or not the coil short circuit time (for example, 2 msec) has elapsed, and when the result is negative, the process proceeds to S18. It is determined whether 10 has slipped (retreated) due to its own weight, in other words, whether or not traveling has started.
[0043]
Specifically, this is performed by determining whether or not a pulse train has started to be output from the rotary encoder 72 as shown in FIG. 13, and more specifically, determining whether or not the electric motor 28 has rotated, for example, 90 °.
[0044]
More strictly, it is determined from the phase of the output pulse of the rotary encoder 72 shown in FIG. 10 whether the rotational direction of the electric motor 28 is opposite to the traveling direction intended by the occupant. For example, when rotating in the reverse direction of 90 °, it may be determined that sliding has occurred (running has started).
[0045]
When the result in S18 is negative, the program proceeds to S20, the motor coil of the electric motor 28 is short-circuited, and the program is terminated.
[0046]
In the next and subsequent program loops, when the result in S16 is affirmative, the process proceeds to S22, and it is determined whether or not the bit of the flag F1 is set to 1. When the result is negative, the process proceeds to S24, and as shown in FIG. A start-up compensation voltage (a first predetermined voltage, for example, 0.6 V) is applied to the motor 28. By applying this startup compensation voltage, the electric motor 28 can be rotated by a small amount to absorb the backlash of the reduction gear 32.
[0047]
Next, in S26, the bit of the flag F1 is set to 1. That is, setting the bit of the flag F1 indicates that the start-up compensation voltage is applied. If the result in S22 is NO, the processes in S24 and S26 are skipped.
[0048]
Next, the process proceeds to S28, in which it is determined whether or not the bit of the flag F2 is 1. When the determination is negative, the process proceeds to S30, where the applied voltage to the electric motor 28 is the startup limit voltage (second predetermined voltage, for example, 1.0 V). It is determined whether or not V2 is exceeded.
[0049]
When the result in S30 is negative, the process proceeds to S32, and it is determined again by the same method whether or not a slip (running start) has occurred. When the result is negative, the process proceeds to S34, and the voltage applied to the electric motor 28 is set to a predetermined value. The program is terminated while increasing at an increase rate (for example, 0.4 V / 400 msec).
[0050]
In this way, after applying the start-up compensation voltage, by performing voltage control to apply a voltage to the electric motor 28 at a predetermined increase rate until the start-up limit voltage is reached, shock due to backlash of the reduction gear 32 is reduced. Or the small electric vehicle 10 can be started smoothly, suppressing.
[0051]
If the result in S30 is affirmative, the program proceeds to S36, and the bit of the flag F2 is set to 1. As a result, in the next and subsequent program loops, the processing from S30 to S34 is skipped and the speed control described later is immediately executed. Even when the result in S18 is affirmative, as shown in FIG. 13, the process from S22 to S36 is skipped and the above-described voltage control is not executed, the process proceeds to speed control, and the applied voltage is controlled so as to immediately reach the target speed.
[0052]
This is because the vehicle may slip down due to its own weight, such as when starting from the slope (uphill road) in the uphill direction, so that speed control is performed immediately to prevent further slipping (inertial running). This is because the backlash of the reduction gear 32 is minimized when sliding down (retracting), and the voltage control described above is essentially unnecessary.
[0053]
Next, in S38, the above speed control is performed.
[0054]
FIG. 15 is a subroutine flow chart for explaining the processing of S38.
[0055]
In the following description, first, in S100, it is determined whether or not the accelerator volume 68 is off last time. If the determination is affirmative, the process proceeds to S102, and it is determined whether or not the traveling speed V is a reference value VREF (eg, 0.7 km / h) or less. . The traveling speed V is calculated from the output of the rotary encoder 72.
[0056]
When the result in S100 is negative and the result in S102 is affirmative, it means that the vehicle is in a very low speed state, in other words, a stop instruction is given after being instructed to stop (acceleration instruction). 11, the same control as the voltage control described in S22 to S36 is executed. However, in this case, the flags F1 and F2 are set to F3 and F4, respectively.
[0057]
That is, in this embodiment, not only when starting from the stop state as shown in FIG. 12, but also when the acceleration is instructed after being instructed to stop as shown in FIG. Voltage control was performed.
[0058]
As a result, even when accelerating again after a stop instruction is given, the speed control can be smoothly performed while reducing or suppressing shock due to backlash of the reduction gear 32.
[0059]
When the result in S110 is affirmative or after the bit of the flag F4 is set to 1 in S118, the process proceeds to S120, and the electric motor 28 is supplied with an increase rate (or decrease, for example) of 2.5 V / 200 msec so as to reach the target speed. Rate control (acceleration / deceleration control) to apply a voltage at a rate.
[0060]
When the result in S102 is negative, the program proceeds to S122, the bits of the flags F3 and F4 are reset to 0, and the program proceeds to S120.
[0061]
Returning to the description of FIG. 11, when the result in S12 is negative, the process proceeds to S40, the bits of the flags F1 and F2 are reset to 0, and the process proceeds to S42 to perform a stop process. If the determination in S14 is affirmative, the process proceeds to S44, the bits of the flags F3 and F4 are reset to 0, and the process proceeds to S38.
[0062]
Since the present invention is configured as described above, even when a large-capacity electric motor 28 is used with emphasis on climbing performance, the start-up shock due to backlash of the reduction gear 32 is reduced or suppressed. The small electric vehicle 10 can be started smoothly.
[0063]
In addition, when acceleration is performed again after a stop instruction is issued, it is possible to smoothly shift to speed control (acceleration control) while reducing or suppressing shock due to backlash of the reduction gear 32.
[0064]
As described above, this embodiment is a control device for the small electric vehicle 10 including the electric motor 28 that drives the wheel 36 via the reduction gear 32, and at least a set speed switch (speed volume) for inputting a set speed. 66), an accelerator lever (accelerator volume 68) for inputting start and stop instructions, and at least outputs of the set speed switch and accelerator lever are input, a target speed is set according to the input, and the set target speed is obtained. In this way, the electric motor control means (control unit 50) for controlling the applied voltage of the electric motor has a first predetermined voltage applied to the electric motor when instructed to start from a stopped state. Immediately apply (startup compensation voltage) and then reach the second predetermined voltage (startup limit voltage) After executing the voltage control for increasing the applied voltage at a predetermined increase rate until the (S10 from S36), said controlling the application voltage such that the target speed (S38, S100 from S122) and as configuration.
[0065]
Further, the electric motor control means is configured to execute the voltage control (S14, S38, S100 to S118) even when a start instruction is input after a stop instruction is input.
[0066]
Furthermore, it comprises travel start determination means (rotary encoder 72) for determining whether or not the travel has started, and when it is determined that the electric motor control means has started travel, the voltage control is stopped and the target is immediately set. The applied voltage is controlled so as to achieve speed (S18, S32, S38, S114, S120).
[0067]
In the above description, the magnetoelectric conversion type rotary encoder is used as the travel start determination means or the rotation direction detection means. However, any sensor such as an optical one can be used as long as the rotation of the electric motor 28 can be detected. It may be used.
[0068]
【The invention's effect】
According to the first aspect, when a start instruction is issued from the stop state, the first predetermined voltage is immediately applied to the electric motor, and then the applied voltage is increased at a predetermined increase rate until the second predetermined voltage is reached. Since it is configured to execute voltage control, that is, it can absorb the backlash of the reduction gear by applying a first predetermined voltage and rotating the electric motor by a small amount, and has a large capacity that emphasizes climbing performance Even when this electric motor is used, it is possible to reduce or suppress the shock at the start due to the backlash of the reduction gear.
[0069]
Further, after executing voltage control for increasing the applied voltage at a predetermined increase rate until the second predetermined voltage is reached, the applied voltage is controlled to achieve the target speed, so that the vehicle can start smoothly. be able to.
[0070]
According to the second aspect of the present invention, since the voltage control is executed even when the start instruction is input after the stop instruction is input, the backlash of the reduction gear is caused even in the reacceleration state. The resulting shock can be reduced or suppressed, and can be smoothly shifted to speed control (acceleration control).
[0071]
According to the third aspect of the present invention, when it is determined that the vehicle has started running, the voltage control is stopped, and the applied voltage is immediately controlled so as to reach the target speed. When a passenger unintentionally slips down, the vehicle can travel in a desired direction while preventing further slipping. In such a case, since the backlash of the reduction gear is normally minimized, the voltage control described above is essentially unnecessary.
[Brief description of the drawings]
FIG. 1 is a plan view of a control device for a small electric vehicle according to one embodiment of the present invention, more specifically, a small electric vehicle housing the control device.
2 is a reduced side view of the small electric vehicle shown in FIG. 1. FIG.
FIG. 3 is a front view of the small electric vehicle shown in FIG. 1;
4 is a rear view of the small electric vehicle shown in FIG. 1. FIG.
FIG. 5 is a block diagram specifically showing a configuration of a control unit mounted on the small electric vehicle of FIG. 1;
6 is a circuit diagram showing details of a motor drive circuit built in the control unit of FIG. 5; FIG.
7 is an enlarged plan view of a main control panel of the small electric vehicle of FIG. 1. FIG.
FIG. 8 is an explanatory diagram of the main control panel shown in FIG.
9 is an explanatory graph showing an output voltage characteristic of a speed volume of the main control panel shown in FIG.
10 is a time chart showing the output of the rotary encoder shown in FIG. 5. FIG.
FIG. 11 is a flowchart for explaining the operation of the control device for the small electric vehicle shown in FIG. 1;
FIG. 12 is a time chart for explaining the processing of the flow chart of FIG. 12 and showing a case of starting from flat ground.
FIG. 13 is a time chart for explaining the processing of the flowchart of FIG. 12 and showing a case of starting from a slope.
FIG. 14 is a time chart for explaining the processing of the flowchart of FIG. 12 and showing a case where a start (acceleration) is instructed after a stop is instructed.
FIG. 15 is a subroutine flowchart of speed control in the flowchart of FIG. 12;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Small electric vehicle 28 Electric motor 32 Reduction gear 50 Control unit (electronic control unit. Electric motor control means)
66 Speed volume (Set speed switch)
68 Accelerator volume (Accelerator lever)
72 Rotary encoder (running start determination means and rotation direction detection means)

Claims (3)

A control device for a small electric vehicle including an electric motor that drives a wheel via a reduction gear,
a. Set speed switch to input the set speed,
b. An accelerator lever for inputting start and stop instructions,
And c. Electric motor control means for inputting at least outputs of the set speed switch and the accelerator lever, setting a target speed according to the input, and controlling an applied voltage of the electric motor so as to be the set target speed;
When the start instruction is issued from the stop state, the electric motor control means immediately applies the first predetermined voltage to the electric motor, and then applies it at a predetermined increase rate until the second predetermined voltage is reached. A control apparatus for a small electric vehicle, wherein after applying voltage control for increasing voltage, the applied voltage is controlled so as to achieve the target speed. 2. The control apparatus for a small electric vehicle according to claim 1, wherein the electric motor control means executes the voltage control even when a start instruction is input after a stop instruction is input. further,
d. Traveling start determining means for determining whether or not traveling has started;
The electric motor control means, when it is determined that traveling has started, stops the voltage control and immediately controls the applied voltage so that the target speed is reached. 3. A control device for a small electric vehicle according to item 2.

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