JP6471880B2 - Electric vehicle traveling control device - Google Patents

Description

  The present invention relates to a travel control device for an electric vehicle, and performs control for preventing dozing.

As a driving control device for a vehicle, when the driver's awakening situation is detected and it is determined that the driver is drowsy, the brake is controlled to cause the vehicle to shake or vibrate so that the driver can fall asleep. Techniques for preventing this have been proposed (for example, prior document 1). By causing the vehicle to sway and vibrate, it is possible to inform the occupants, including the driver, that the driver is less awake,
It becomes possible to suppress the driver's drowsy driving.

  In recent years, various electric vehicles have become widespread due to concern about environmental problems. As an electric vehicle, an electric vehicle that runs the vehicle by the driving force of the electric motor, a hybrid electric vehicle that charges the battery by the engine and runs the vehicle by the driving force of the electric motor by the electric power from the battery, and the battery is charged by the engine 2. Description of the Related Art There is known an electric automobile that runs a vehicle with an electric motor and / or engine driving force.

  Even in such an electric vehicle, there is a demand for a technique that can suppress the driver's drowsiness by applying vibration to the entire vehicle. However, in the field of electric vehicles, the actual situation is that a technique for suppressing the driver's doze by applying vibration to the entire vehicle has not been established. When the technology for simply controlling the brake is combined as in the prior art document 1, there is a possibility that a new problem arises that the vehicle speed decreases and the surrounding vehicle or the like is disturbed.

JP 2004-216955 A

  The present invention has been made in view of the above circumstances, and is an electric vehicle that travels by driving an electric motor, which vibrates the vehicle without decreasing the vehicle speed and prevents the driver from falling asleep without decreasing the vehicle speed. An object of the present invention is to provide a travel control device for an electric vehicle.

  In order to achieve the above object, a travel control device for an electric vehicle according to a first aspect of the present invention includes an electric motor serving as a travel drive source of the vehicle, an arousal state detecting means for detecting a driver's arousal state, and the electric motor. Control means for varying the magnitude of the output torque of the electric motor when the wakefulness detection means detects that the degree of wakefulness of the driver is low during traveling by driving of the motor. The torque is a torque obtained by combining a required torque for travel driving required in accordance with the driver's accelerator operation and a vibration torque applied to obtain an amplitude at a predetermined frequency. The vehicle speed increases as the vehicle speed increases.

  In the present invention according to claim 1, by varying the magnitude of the output torque of the electric motor for traveling, the vehicle can be driven with the output torque that includes the torque necessary for traveling and fluctuates. For this reason, when it is detected by the wakefulness detection means that the degree of wakefulness of the driver is low, the output speed is changed in a state where the influence on the vehicle speed is suppressed (without reducing the vehicle speed), It is possible to prevent the driver from falling asleep by vibrating the vehicle in a state where the decrease in the vehicle is eliminated.

  The sum of the vibration torque applied to obtain the required torque for driving and the amplitude can be used as the output torque, and the output torque can be vibrated without lowering the vehicle speed.

  That is, while the integral value of the required torque required for running increases, the integral value does not increase or decrease because the vibration torque is a plus or minus repetition. Since the output torque is obtained by adding the vibration torque to the required torque, the ratio of the vibration torque (output torque−required torque) to the required torque converges when a certain time elapses. That is, the output torque is accumulated after a certain period of time, and the required torque is integrated and the vibration torque changes within a certain range. Does not increase or decrease. For this reason, the output torque hardly changes and the vehicle speed is maintained.

  Therefore, in an electric vehicle that is driven by the drive of the electric motor, vibration can be applied to the vehicle without reducing the vehicle speed, and the driver can be prevented from falling asleep without reducing the vehicle speed.

  The electric vehicle according to the present invention is an electric vehicle that drives the vehicle by the driving force of the electric motor, a hybrid electric vehicle that charges the battery by the engine and runs the vehicle by the driving force of the electric motor by the electric power from the battery, and the battery that is charged by the engine In addition, an electric automobile and / or an electric vehicle that drives the vehicle with the driving force of the engine is applied, and the control is performed in a state where the driving force is obtained by the electric motor.

  An electric vehicle travel control apparatus according to a second aspect of the present invention is the electric vehicle travel control apparatus according to the first aspect, wherein an upper limit value is provided for the vibration torque. An electric vehicle travel control apparatus according to a third aspect of the present invention is the electric vehicle travel control apparatus according to the first or second aspect, wherein the vehicle speed is less than a predetermined threshold value. Does not apply the vibration torque.

  The vibration torque is torque that alternately applies acceleration torque applied in the acceleration direction and deceleration torque applied in the deceleration direction, and the magnitude of the acceleration torque is equal to the magnitude of the deceleration torque. It is preferably set.

  As a result, the acceleration torque and the deceleration torque having the same magnitude are alternately applied as the vibration torque, so that the influence of the application of the vibration torque on the average vehicle speed can be minimized.

  Further, it is preferable that the vibration torque is set so that the number of times of applying the acceleration torque and the number of times of applying the deceleration torque are equal.

  Thereby, the change of the vehicle speed can be suppressed before and after the application of the vibration torque.

  Moreover, it is preferable that the said control means makes the said vibration torque zero when the time change rate of the said request torque is more than predetermined value.

  As a result, when the time change rate of the required torque exceeds a predetermined value (when the required torque changes suddenly), the vibration becomes relatively small even if the vibration torque is superimposed, and the vibration cannot be recognized. The torque is set to zero so that the output torque is not vibrated. In addition, when the rate of change of the required torque over time is greater than or equal to a predetermined value (when the required torque changes suddenly), if the vibration torque becomes a vibration in the acceleration direction, there is a risk of further sudden acceleration. This prevents vibration from being applied to the output torque.

  Moreover, it is preferable that the said control means changes the vibration amplitude of the said vibration torque according to the driving state of the said vehicle.

  Thus, for example, as described in claim 1, by increasing the vibration amplitude of the vibration torque as the vehicle speed increases, the vehicle speed increases by increasing the vibration amplitude when the vehicle speed increases. Accordingly, the vibration width of the vibration torque can be increased. For this reason, even if the minute vibration in the vehicle increases as the vehicle speed increases, the vibration for awakening can be transmitted to the driver, and a snooze can be prevented.

  An electric vehicle travel control apparatus according to a fourth aspect of the present invention is the electric vehicle travel control apparatus according to any one of the first to third aspects, wherein the instruction to change the output torque is An informing means for informing the output to the electric motor is provided.

  In the present invention according to claim 4, it is possible to notify the notification means that the output torque is in a fluctuating state, i.e., a driving that suppresses dozing. be able to.

  The travel control device for an electric vehicle according to the present invention is an electric vehicle that travels by driving an electric motor, and can vibrate the vehicle to prevent the driver from falling asleep.

It is the schematic of the electric vehicle provided with the traveling control apparatus which concerns on one Example of this invention. It is a block block diagram of the traveling control apparatus which concerns on one Example of this invention. It is explanatory drawing of the relationship between the demand torque and the amount torque of output torque. This is the integrated status of the required torque. This is the integrated state of vibration torque. It is a control flowchart of a traveling control apparatus. It is a graph explaining the relationship between a vehicle speed and vibration torque. It is a time chart at the time of dozing suppression driving.

  An electric vehicle equipped with a travel control apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall schematic situation of an electric vehicle equipped with a travel control apparatus according to an embodiment of the present invention, and FIG. 2 shows a block configuration of the travel control apparatus.

  The illustrated electric vehicle includes a battery that is charged from an external power source, and a vehicle that travels with an electric motor driven by electric power from the battery is described as an example. The electric vehicle of the present invention includes a hybrid electric vehicle in which a battery is charged by the engine and the vehicle is driven by the driving force of the electric motor by the electric power from the battery, and the battery is charged by the engine and the electric motor and / or the engine is driven. It is also possible to apply an electric vehicle that drives the vehicle with force.

  As shown in the figure, an electric vehicle 1 as an electric vehicle includes a battery 2 that is charged from an external power source. The electric power of the battery 2 is supplied to the traveling electric motor 4 via the inverter 3, and the electric motor 4 is driven based on an instruction of a predetermined output torque. The electric vehicle 1 travels in a desired state by driving the electric motor 4.

  The electric vehicle 1 is provided with a travel control means 6, and information on the driving state and the vehicle speed sensor 5 is input to the travel control means 6. The travel control means 6 calculates a required torque (torque required for travel) according to the situation of the vehicle (for example, an accelerator operation that is the amount of depression of the accelerator pedal), and the travel control means 6 An instruction for the required torque is output at The instruction of the required torque is input to the awakening control means 7 as a control means, and the awakening control means 7 calculates an output torque by superimposing a vibration torque described later on the required torque.

  The electric vehicle 1 is provided with a wake-up determination camera 12 as wake-up state detecting means for detecting the wake-up state of the driver 11. By grasping the situation of the driver 11 by the awakening determination camera 12, the awakening state of the driver 11 is estimated. As the arousal state detection means, a means for detecting the operation state of the steering wheel, an electroencephalogram measurement means embedded in a seat, a means for measuring body temperature and blood pressure can be used in combination or independently.

  The detection information of the awakening determination camera 12 is input to the awakening control means 7, and when it is determined (detected) that the driver 11 has a low degree of awakening, the output torque of the electric motor 4 is vibrated at a predetermined frequency. Let That is, the magnitude of the output torque by the electric motor 4 is varied.

  That is, when it is detected that the degree of arousal of the driver 11 is low during traveling by driving of the electric motor 4, the awakening control means 7 needs a vibration torque that causes the torque to vibrate with a predetermined amplitude. An output torque (required torque + vibration torque) that is superimposed on the required torque and vibrates at a predetermined frequency is calculated.

  The instruction of the output torque calculated by the awakening control means 7 is sent to the electric motor 4 through the inverter 3, and the electric motor 4 is driven with the output torque that vibrates at a predetermined frequency. Thereby, when the driver | operator 11's awakening degree is low, the electric vehicle 1 will vibrate back and forth, and the driver | operator 11 can be awakened and doze can be prevented.

  When an instruction for output torque to which vibration torque that vibrates at a predetermined frequency is applied is sent, the indicator lamp 13 (notification means) for notifying that traveling that prevents a doze is being performed is turned on. The Since the indicator lamp 13 is turned on when an instruction of output torque to which the vibration torque that vibrates at a predetermined frequency is applied to the electric motor 4 is turned on, the output torque is vibrated, that is, doze It is possible to notify the driver 11 and other occupants with the indicator lamp 13 that the driving is preventing the vibration, and the vibration can be distinguished from the normal traveling of the electric vehicle 1.

  In addition, as a notification means, it is also possible to apply a means for notifying (in addition to) the indicator lamp 13 and notifying that the operation that suppresses the dozing is performed by voice.

  In the traveling control device described above, the output torque of the traveling electric motor 4 is vibrated, so that the torque required for traveling (required torque) and the vibration torque that vibrates at a predetermined frequency are superimposed on each other. Can be run.

  Therefore, when the arousal determination camera 12 detects that the degree of arousal of the driver 11 is low, driving with the output torque oscillated while suppressing the influence on the vehicle speed (without reducing the vehicle speed). The person 11 can be prevented from falling asleep.

  Accordingly, in the electric vehicle 1 that is driven by the drive of the electric motor 4, it is possible to give the electric vehicle 1 vibration in the front-rear direction without reducing the vehicle speed, and to prevent the driver 11 from falling asleep without reducing the vehicle speed. Become.

  And when it is detected that the degree of arousal of the driver 11 is low, the electric vehicle 1 is vibrated in the front-rear direction to prevent the driver 11 from falling asleep. Can be informed that the degree of awakening is low.

  A situation where the output torque is vibrated in a state in which the influence on the vehicle speed is suppressed (without reducing the vehicle speed) will be described with reference to FIGS.

  FIG. 3 shows a graph for explaining the change over time between the required torque and the output torque on which the vibration torque is superimposed, and FIG. 4 shows a graph for explaining the integrated state (time integrated state) of the output torque.

  Further, FIG. 5 shows a graph for explaining a situation in which the ratio of vibration torque is integrated (a situation in which time integration is performed). That is, the situation in FIG. 5 is the change over time when the request torque is subtracted from the output torque (request torque + vibration torque) and the value divided by the request torque (vibration torque ratio) is integrated, that is, the integration of the output torque. The change with time of the ratio of the integrated value of the vibration torque to the value is shown.

  As shown in FIG. 3, a required output (indicated by a dotted line in the figure) required for traveling is set according to the driving situation of the electric vehicle 1, and the vibration torque that causes the torque to vibrate with a predetermined amplitude is set as the required torque. Overlaid, an output torque (shown by a solid line in the figure) that vibrates at a predetermined frequency is set. That is, the output torque is (requested torque + vibration torque).

  The vibration torque is a torque that is alternately and repeatedly applied a positive torque (acceleration torque) applied in the direction of accelerating the vehicle and a negative torque (deceleration torque) applied in the direction of decelerating the vehicle. The magnitudes of the acceleration torque and the deceleration torque are set to be equal, and the integrated value of the vibration torque when the acceleration torque and the deceleration torque are applied once is zero. For this reason, the influence of the application of the vibration torque on the average vehicle speed can be minimized.

  As shown in FIG. 3, when the application of vibration torque is started, acceleration torque is first applied, and then deceleration torque is applied. Then, when the application of the vibration torque is finished, the process is finished with the application of the deceleration torque. That is, the number of times of applying acceleration torque and the number of times of applying deceleration torque are set equal. For this reason, a change in the vehicle speed can be suppressed before and after applying the vibration torque.

  The time integrated value of the value of the required torque that is necessary for traveling increases. On the other hand, since the value of the vibration torque is a repetition of plus and minus, the time integrated value of the value of the vibration torque converges to a certain value range (almost zero). The output torque accumulates the required torque as time passes, and the vibration torque changes at a constant value. Therefore, the ratio of vibration torque to the accumulated request torque (change in vehicle speed) is constant time. As time passes, it becomes extremely small.

  For this reason, as shown in FIG. 5, the integral value (the ratio of the integral value of the vibration torque) obtained by subtracting the required torque from the output torque and dividing by the required torque, that is, {(integral value of output torque−required torque Integral value) / integrated value of required torque} decreases with time. When the application of the vibration torque is stopped at time T2 in FIG. 5, the ratio of the integrated value of the vibration torque to the integrated value of the output torque returns to 0 (that is, the state before the application of the vibration torque).

  This is because the number of times of applying acceleration torque and the number of times of applying deceleration torque are the same as shown in FIG. Therefore, the output torque hardly changes before and after applying the vibration torque, and the vehicle speed is maintained.

  Based on FIGS. 6-8, the specific operation | movement of the driving | operation which suppresses the driver's 11 dozing is demonstrated.

  FIG. 6 is a control flowchart of driving that suppresses the driver 11 from falling asleep, FIG. 7 is a graph for explaining the relationship between the vehicle speed and the vibration torque, and FIG. A time chart showing values, output torque, and status of indicator lights is shown.

  As shown in FIG. 6, vehicle speed information is acquired in step S1, and it is determined in step S2 whether the vehicle speed h is equal to or higher than a threshold value hmin. When it is determined in step S2 that the vehicle speed h is equal to or higher than the threshold value hmin, the required torque required for traveling is acquired in step S3, and information on the awakening determination camera 12 is acquired in step S4.

  If it is determined in step S2 that the vehicle speed h is less than the threshold value hmin, the process ends. That is, when the vehicle speed is low, such as when the vehicle is stopped, the process for preventing the dozing is not performed.

  After the information of the awakening determination camera 12 is acquired in step S4, it is determined whether or not the driver is not awakened in step S5, and the driver is not awakened in step S5 (the possibility of doze driving is possible). In step S6, it is determined whether or not the required torque has changed suddenly.

  If it is determined in step S6 that the required torque has not changed suddenly, the vibration torque corresponding to the vehicle speed is read from the map in step S7, and the indicator lamp 13 is turned on in step S8. The vibration torque can be calculated according to the vehicle speed.

  Based on FIG. 7, the relationship between vehicle speed and vibration torque will be described.

  When the vehicle speed is the threshold value (hmin) and the value (absolute value) of the vibration torque is set to the predetermined value T, the vibration torque value gradually increases as the vehicle speed increases. An upper limit value Tmax is set as the value of the vibration torque, and the value of the vibration torque is fixed to the upper limit value Tmax at a vehicle speed equal to or higher than a predetermined vehicle speed h.

  That is, the magnitude of the vibration torque (the amplitude of vibration of the output torque) is increased (changed) in accordance with the vehicle speed that is the running state of the vehicle. Therefore, by increasing the amplitude of the output torque vibration when the vehicle speed increases, even if the minute vibration in the vehicle increases in accordance with the increase in the vehicle speed, the vibration for awakening is transmitted to the driver 11. Can be prevented from falling asleep.

  Furthermore, by providing the upper limit value Tmax for the magnitude of the vibration torque, it is possible to eliminate the possibility that the application of the vibration torque will significantly hinder the running state of the vehicle.

  The amplitude and frequency of the vibration torque are not limited to those described above, and can be set as appropriate. For example, the amplitude and frequency may be set based on the degree of arousal state of the driver 11 detected by the arousal state detection means. In this way, the driver 11 can be awakened more quickly.

  Returning to the flowchart of FIG. 6, after the vibration torque corresponding to the vehicle speed is read and the indicator lamp 13 is turned on, the output torque is set by adding (overlapping) the required torque and the vibration torque in step S9. In step S10, an output torque instruction is output and the process ends.

  That is, the vibration torque according to the vehicle speed is added to the required torque to set the output torque, and the electric motor 4 is driven with the output torque that vibrates according to the vehicle speed.

  On the other hand, if it is determined in step S5 that the driver is awake (no possibility of dozing), the vibration torque is set to zero in step S11, the indicator lamp 13 is turned off in step S12, and step S9. Migrate to In step S9, the required torque is set as the output torque, and the electric motor 4 is driven with the output torque that does not vibrate.

  If it is determined in step S6 that the required torque has suddenly changed, the vibration torque is set to zero in step S11, and the indicator lamp 13 is turned off in step S12, as in the case where there is no possibility of falling asleep. The process proceeds to step S9. In step S9, the required torque is set as the output torque, and the electric motor 4 is driven with the output torque that does not vibrate.

  That is, the vibration torque is set to zero in the traveling state where the required torque changes suddenly. When the required torque changes suddenly, even if the vibration torque is superimposed, the vibration becomes relatively small and the vibration cannot be recognized. Therefore, the vibration torque is set to zero so that the output torque is not given vibration.

  Further, when the required torque changes suddenly, if the vibration torque becomes a vibration in the acceleration direction, there is a possibility of further rapid acceleration. Therefore, the vibration torque is set to zero so that the output torque is not vibrated.

  Based on FIG. 8, the state of sleepiness, the vehicle speed, the required torque value, the output torque, and the indicator lamp 13 at the time of driving that gives vibration to the output torque to prevent a drowsiness will be described.

  As shown in FIG. 8 (a), the value of the required torque is constant (in a state where the accelerator is depressed), and as shown in FIG. 8 (b), the driver is driven by the awakening determination camera 12 at time t1. When it is detected that the sleepiness of No. 11 is high, an output torque in which the vibration torque is superimposed on the required torque is instructed as shown in FIG. Since the vibration torque is superimposed on the output torque, the electric motor 4 is driven by the vibration output torque.

  As shown in FIG. 8D, the indicator lamp 13 is turned on at time t1. And the value of the vibration torque is positive and negative, and the output torque is a torque obtained by superimposing the vibration torque on the required torque required for running, so the total torque does not decrease over time, As shown in FIG. 8 (e), the vehicle speed is kept substantially constant.

  Therefore, the electric vehicle 1 that travels by driving the electric motor 4 can vibrate the electric vehicle 1 without reducing the vehicle speed.

  As shown in FIG. 8 (b), when it is detected by the awakening determination camera 12 that the driver 11 is awake at time t2, as shown in FIG. 8 (c), the output with the vibration torque set to zero is output. Torque is commanded. Since the output torque does not overlap with the vibration torque, the electric motor 4 is driven with the output torque that does not vibrate.

  As shown in FIG. 8 (d), the indicator lamp 13 is turned off at time t2, and the vehicle speed is kept constant as shown in FIG. 8 (e).

  The required torque during inertia traveling is zero, and when the awakening determination camera 12 detects that the driver 11 is drowsy, the vibration torque becomes the output torque. When the output torque in the vibration state is instructed, when awakening is detected and the vibration is terminated, a torque shock is generated depending on the state of the vibration torque.

  When ending vibration, the value of vibration torque is positive and negative, so the timing to end vibration is set to positive and negative transition time (zero time). The vibration can be terminated without the torque shock.

  In particular, when starting the application of vibration torque from a positive torque, the application of vibration torque is terminated at the transition from negative to positive, thereby eliminating the torque shock while reducing the time integral value of vibration torque to zero. The vibration can be terminated. That is, the time integral value of the vibration torque can be made zero by equalizing the magnitudes of the positive torque and the negative torque and equalizing the number of times of applying the positive torque and the number of times of applying the negative torque.

  The above-described travel control device for an electric vehicle outputs a torque obtained by combining a required torque required for traveling the electric vehicle 1 and a vibration torque for obtaining vibration at a predetermined frequency in order to vibrate when the degree of arousal is low. Torque is used. Since the vibration torque repeats plus and minus, the total output torque does not decrease, and the output torque in a state where the vibration torque is superimposed on the required torque required for traveling does not decrease over time.

  For this reason, when the driver 11 is not awakened, the vehicle can be vibrated without decreasing the vehicle speed by driving the electric motor 4 with the output torque that does not decrease over time. Therefore, it is possible to prevent the driver 11 from falling asleep without reducing the vehicle speed.

  The present invention can be used in the industrial field of travel control devices for electric vehicles.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Battery 3 Inverter 4 Electric motor 5 Vehicle speed sensor 6 Travel control means 7 Awakening control means 11 Driver 12 Awakening determination camera 13 Indicator light

Claims (4)

An electric motor as a driving source of the vehicle;
An arousal state detecting means for detecting a driver's arousal state;
Control means for changing the magnitude of the output torque by the electric motor when the wakefulness detection means detects that the degree of awakening of the driver is low during traveling by driving the electric motor,
The output torque is
A torque that combines the required torque for driving required according to the driver's accelerator operation and the vibration torque applied to obtain the amplitude at a predetermined frequency;
The traveling control device for an electric vehicle, wherein the vibration torque increases as the speed of the vehicle increases. The travel control device for an electric vehicle according to claim 1,
An upper limit value is provided for the vibration torque. In the travel control device for an electric vehicle according to claim 1 or 2,
The travel control device for an electric vehicle, wherein the vibration torque is not applied when the vehicle speed is less than a predetermined threshold value. In the travel control device for an electric vehicle according to any one of claims 1 to 3,
A travel control device for an electric vehicle, comprising: an informing means for informing that an instruction to vary the output torque is output to the electric motor.

Images