CN100400332C - Vehicle and vehicle control method - Google Patents

Abstract

The present invention relates to a vehicle and a control method for the vehicle. Specifically, it relates to a vehicle including an electric motor capable of outputting power to a drive shaft connected to drive wheels, and a control method thereof. It is possible to reduce the torque shock when the slip is suppressed while ensuring the running stability of the vehicle. When slipping occurs, the torque upper limit Tmax is used to limit the requested torque requested by the driver, and the vehicle is judged to be in an unstable state when it is turning or driving on a slope at a very low speed. Compared with the relaxation of the torque shock when limiting the required torque, the rapid convergence of slippage is prioritized, and the torque upper limit Tmax is adjusted; when the vehicle is running on a flat road at a low speed without steering, it is judged that the vehicle is In a stable state, the torque upper limit value Tmax is adjusted so as to moderate the torque shock when the requested torque is restricted with priority.

Description

Vehicle and vehicle control method

technical field

The present invention relates to a vehicle including a motor capable of outputting power to a drive shaft connected to drive wheels and a control method thereof.

Background technique

Conventionally, as such a vehicle, there has been proposed a vehicle that estimates the road surface gradient and suppresses the output of the engine when excessive slip occurs in the drive wheels (see JP-A-7-77080). In this vehicle, when excessive slippage occurs, when it is estimated that it is an uphill road, in order to converge the excessive slippage, the necessary initial control torque is corrected in the direction of increase, and then the engine is driven and controlled, thereby preventing excessive slippage from occurring. The initial control torque is lowered to be more than a necessary value at the time of slipping, thereby ensuring the acceleration performance of the vehicle when traveling uphill.

Contents of the invention

In such a vehicle, when a motor whose control output response is faster than that of an engine is used as a driving power source, shock (vibration) may occur due to suppression of output when excessive slip occurs. Case. On the other hand, when the vehicle slips in an unstable state, it is necessary to quickly converge the slip to ensure the driving stability of the vehicle.

One of the objects of the vehicle of the present invention is to solve such a problem and to suppress the shock when the torque output to the drive shaft is limited when slip occurs. In addition, another object of the vehicle of the present invention is to suppress the shock when the torque output to the drive shaft is limited when slip occurs while ensuring the running stability of the vehicle.

The vehicle of the present invention adopts the following means in order to achieve at least part of the above objects.

The vehicle of the present invention is a vehicle provided with an electric motor capable of outputting power to a drive shaft connected to a drive wheel, and is characterized in that it includes: a slip detection device for detecting slippage caused by idling of the drive wheel; A running state detection device for a running state; when slipping is detected by the above-mentioned slipping detection device, according to the running state of the vehicle detected by the above-mentioned running state detection device, it is set as the torque output for sharply limiting the upper drive shaft a sudden limit suppression degree setting device for a degree of sudden restriction suppression at the time of suppression; and a control device for driving and controlling the motor so as to limit the torque output to the drive shaft by using the above set rapid restriction suppression degree .

In the vehicle of the present invention, according to the running state of the vehicle when slipping is detected, the degree of sudden restriction suppression is set as the degree when the torque output to the drive shaft is suppressed abruptly, and by using this setting The electric motor that can output power to the drive shaft is controlled by limiting the torque output to the drive shaft with a predetermined degree of sharp limit suppression. Therefore, it is possible to suppress the shock at the time of limiting the torque output to the drive shaft accompanying the detection of slip to an extent based on the running state of the vehicle, and at the same time to suppress the slip. Here, the motor may be a single motor shared by the left and right wheels as drive wheels.

In such a vehicle according to the present invention, it is also possible to set the abrupt limit suppression degree setting means to set the abrupt limit as the detected running state of the vehicle tends to be less stable. A device that limits the degree of inhibition. In this way, when the vehicle is in a relatively unstable tendency, the degree of suppression of the sharp limitation of the torque output to the drive shaft is reduced, and the slipping is quickly converged, thereby ensuring the running stability of the vehicle; When the tendency is stable, the degree of suppression of the sudden limitation of the torque output to the drive shaft is increased, thereby reducing the shock.

In addition, in the vehicle of the present invention, it is also possible to set the aforementioned driving state detecting means as a device having a steering amount detecting means for detecting the steering amount of the vehicle; the aforementioned sudden limit suppression degree setting means is based on the detected It is a device to set the degree of suppression of the aforementioned sharp limit according to the amount of steering of the vehicle. In addition, it can also be set that the aforementioned driving state detecting device is a device having a vehicle speed detecting device that detects the vehicle speed of the aforementioned vehicle; The vehicle speed of the vehicle is used to set the degree of suppression of the aforementioned sharp limit. Furthermore, it is also possible to set the sudden limit suppression degree setting means to be smaller than usual when the detected steering amount of the vehicle and the detected vehicle speed are in the process of turning and running. The way to set the degree of suppression of the aforementioned sharp limit means. Alternatively, the abrupt restriction suppression degree setting means may be configured to set the abrupt restriction suppression degree so that the detected running state of the vehicle tends to be less stable.

Furthermore, in the vehicle of the present invention, it may also be set that the aforementioned driving state detecting means is a device having a road surface gradient detecting means for detecting the road surface gradient; Means for setting the degree of suppression of the aforementioned sharp limit. In addition, it can also be set that the aforementioned driving state detecting device is a device having a vehicle speed detecting device that detects the vehicle speed of the aforementioned vehicle; A device to set the degree of suppression of the aforementioned sharp limit. Furthermore, it can also be set that the above-mentioned sudden limit suppression degree setting device is to become It is a device to set the above-mentioned sharp limit suppression degree smaller than usual. In addition, it can also be set that the said abrupt limit suppression degree setting means is to become faster than the normal speed when the detected road gradient is lower than the second predetermined slope and the detected vehicle speed is lower than the second predetermined vehicle speed. The device that sets the degree of suppression of the aforementioned sharp limit as large as possible. In these cases, it is possible to add as a condition that the steering amount of the vehicle is smaller than the prescribed steering amount.

In addition, in the vehicle of the present invention, it is also possible to set a rotational acceleration detection device for detecting the rotational acceleration of the drive shaft; The torque limit value set by the detected rotational angular acceleration of the drive shaft is used as the lower limit value when the required torque required by the drive shaft is limited, and is used as the degree of sudden limit suppression, thereby limiting the torque to the The torque output by the drive shaft is used to drive and control the device of the aforementioned electric motor.

In addition, the present invention can also be an aspect of a control method of a vehicle other than the above-mentioned aspect of the vehicle.

Description of drawings

FIG. 1 is a structural diagram schematically showing the structure of an automobile 20 as an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of a drive control program executed by the electronic control unit 70 of the automobile 20 of the embodiment.

FIG. 3 is a graph showing the relationship among the accelerator opening degree Acc, the vehicle speed V, and the required torque Td*.

FIG. 4 is a flowchart showing an example of a slip determination processing routine executed by the electronic control unit 70 of the automobile 20 of the embodiment.

FIG. 5 is a flowchart showing an example of a processing routine executed by the electronic control unit 70 of the automobile 20 of the embodiment when a slip occurs.

FIG. 6 is a graph showing the relationship between the rotational angular acceleration α of the drive shaft 28 and the torque upper limit Tmax.

FIG. 7 is a flowchart showing an example of an adjustment torque setting processing program executed by the electronic control unit 70 of the automobile 20 of the embodiment.

FIG. 8 is a graph showing the relationship between the vehicle speed V, the steering angle θst, and a predetermined steering region.

FIG. 9 is a graph showing the relationship between slip generation torque Tmslip and adjustment torque TL.

FIG. 10 is a flowchart showing an example of a processing routine at the time of slipping and convergence executed by the electronic control unit 70 of the automobile 20 of the embodiment.

FIG. 11 is an explanatory diagram showing a time-varying state of the target torque Tm* and the rotational angular acceleration α when the torque output to the drive shaft 28 is limited due to the occurrence of slip.

FIG. 12 is a configuration diagram schematically showing the configuration of an automobile 120 according to a modified example.

FIG. 13 is a configuration diagram schematically showing the configuration of an automobile 220 according to a modified example.

FIG. 14 is a configuration diagram schematically showing the configuration of an automobile 320 according to a modified example.

Detailed ways

Next, specific embodiments of the present invention will be described using examples. FIG. 1 is a structural diagram briefly showing the structure of an automobile 20 as one embodiment of the present invention. The automobile 20 of the embodiment, as shown in the figure, is equipped with a drive shaft 28 capable of outputting power to the drive shaft 28 mechanically connected to the drive wheels 62a, 62b via the differential gear 29 by using the electric power supplied from the battery 26 via the inverter circuit 24. The electric motor 22, and the electronic control unit 70 that controls the vehicle as a whole.

The motor 22 is constituted as, for example, a well-known synchronous generator motor that can function both as a motor and as a generator; The power of multiple switching elements constitutes.

The electronic control unit 70 is configured as a microprocessor centered on a CPU (Central Processing Unit) 72, and in addition to the CPU 72, includes a ROM 74 storing processing programs, a RAM 76 temporarily storing data, and input/output ports (not shown). The rotational position θd from the rotational position detection sensor 32 that detects the rotational position of the rotational shaft (drive shaft 28) of the motor 22, the wheel speeds from the wheel speed sensors 34a, 34b that detect the respective wheel speeds of the drive wheels 62a, 62b , the wheel speeds from the wheel speed sensors 36a, 36b that detect the wheel speeds of the non-driven wheels 64a, 64b, the vehicle speed V from the vehicle speed sensor 52 that detects the running speed of the vehicle, and the gradient from the road surface on which the vehicle is running. The road surface gradient θgr from the gradient sensor 54, the steering angle θst from the steering angle sensor 56 that detects the steering angle of the vehicle, the shift lever position SP from the shift lever position sensor 82 that detects the operating position of the shift lever 81, and the shift lever position SP from the detection acceleration. The accelerator position Acc of the accelerator pedal position sensor 84 for the depression amount of the pedal 83 and the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85 are input to the Inside the electronic control unit 70 . In addition, a switching control signal to the switching elements of the inverter circuit 24 and the like are output from the electronic control unit 70 via the output port.

The operation of the vehicle 20 configured in this way will be described, particularly, the operation of determining whether or not slipping has occurred due to idling of the drive wheels 62a, 62b and then controlling the drive of the motor 22 will be described. FIG. 2 is a flowchart showing an example of a drive control program executed by the electronic control unit 70 of the automobile 20 of the embodiment. This program is repeatedly executed at predetermined intervals (for example, every 8 msec).

After the drive control program is executed, the CPU 72 of the electronic control unit 70 first inputs the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 52, and calculates The rotation speed Nd of the drive shaft 28 is determined (step S100), and the required torque Td* to be output to the drive shaft 28 is set according to the input accelerator opening Acc and vehicle speed V (step S102). Here, the setting of the required torque Td*, in the embodiment, obtains the relationship between the accelerator opening degree Acc, the vehicle speed V and the required torque Td* in advance, then makes a table and stores it in the ROM 74 in advance. When the degree Acc and the vehicle speed V are calculated, the corresponding required torque Td* will be derived from the graph. An example of this graph is shown in FIG. 3 .

Next, calculate the rotation angular acceleration α of the rotation shaft 28 according to the input rotation speed Nd of the drive shaft 28 (step S104), and then judge whether slippage occurs on the drive wheels 62a, 62b based on the calculated rotation angular acceleration α. Or a slip judgment process of whether or not the generated slip has converged (step S106). Here, the calculation of the rotational angular acceleration α, in the embodiment, is by subtracting the previous rotation speed Nd input in the previous program from the current rotation speed Nd input in the current program (the current rotation speed Nd− The previous speed Nd) is carried out. Furthermore, if the unit of rotational angular acceleration α represents the unit of the rotational speed Nd with the rotational speed [rpm] per minute, then in the embodiment, because the execution time interval of this program is 8msec, it is [rpm/8msec ]. Of course, any unit may be used as long as it can be expressed as a time rate of change of the rotational speed. In addition, as the rotation angular acceleration α, in order to reduce errors, an average value of angular accelerations calculated several times (for example, three times) before the start of the program of this time may be used. Hereinafter, the content of the slip determination processing will be described in detail.

FIG. 4 is a flowchart showing an example of a slip determination processing routine executed by the electronic control unit 70 of the automobile 20 of the embodiment. After the slip determination process program is started, the CPU 72 of the electronic control unit 70 determines whether the rotational angular acceleration α calculated in step S104 of the drive control program of FIG. Threshold value α slip (step S150), when judging that rotational angular acceleration α surpasses threshold value α slip, just judge that drive wheel 62a, 62b idling and skidding takes place, and the skidding generation sign F1 that will represent the generation of skidding is set to 1 value (step S152), end this procedure.

When it is determined that the rotational angular acceleration α does not exceed the threshold value αslip, it is determined whether or not the value of the slip occurrence flag F1 is 1 (step S154 ). When it is determined that the slip occurrence flag F1 is a value of 1, it is determined whether the rotational angular acceleration α is a negative value and this state has continued for a predetermined time or more (steps S156, S158), when it is determined that the rotational angular acceleration α is a negative value And when this state has continued for a predetermined time or more, it is judged that the slipping that occurred on the driving wheels 62a, 62b has converged, and the slipping convergence flag F2 of the slipping that has converged is set to 1 value (step S160), and ends this program. When it is determined that the rotation angular acceleration α is not a negative value, or when it is determined that the angular acceleration α is a negative value but the state has not continued for a predetermined time or more, it is determined that the generated slip has not yet converged, and this routine ends. Furthermore, when it is determined in step S154 that the slippage occurrence flag F1 is not 1, it is judged that no slippage has occurred, and this routine ends.

Returning to the drive control routine of FIG. 2 , when the determination of slippage is completed in this way, processing corresponding to the determination result is performed (steps S108 to S116 ). Specifically, when it is determined that both the slip occurrence flag F1 and the slip convergence flag F2 have a value of 0, and no slip occurs (grip state), the required torque Td* set in step S102 is set as 22 target torque Tm* (step S110), and perform a process of driving and controlling the motor 22 according to the set target torque Tm* (step S116), and then end this routine. In addition, when it is determined that the slip occurrence flag F1 has a value of 1 and the slip convergence flag F2 has a value of 0, and slip occurs, then the processing (step S112) is performed when slip occurs; when it is determined that the slip occurrence flag F1 and the slip convergence flag F2 Be 1 value, when the slipping that takes place has converged, carry out the processing (step S114) when slipping converges, then carry out the processing (step S116 of drive control motor 22 according to the target torque Tm* of motor 22 set in each process) ), and end the program. The drive control of the motor 22 is specifically performed by outputting a switching control signal to the switching elements of the inverter circuit 24 so as to output a torque commensurate with the target torque Tm* to the drive shaft 28 . Hereinafter, the processing at the time of occurrence of slip and the processing at the time of convergence of slip will be described in detail in order.

The processing when slipping occurs is to limit the required torque Td* required by the drive shaft 28 to set the target torque Tm* of the motor 22 in order to suppress the slipping that occurs. According to the processing program when slipping occurs in FIG. 5 to execute. When this skidding occurs, after the processing starts the program, the CPU 72 of the electronic control unit 70 first judges whether the rotational angular acceleration α calculated in the step S104 of the drive control program of Fig. 2 exceeds the peak value α peak (step S200), when the rotational angular acceleration When α exceeds the peak value αpeak, a process of updating the peak value αpeak to the rotational angular acceleration α is performed (step S202). Here, the peak value αpeak is basically a value when the rotational angular acceleration α rises due to the occurrence of slip and appears as a peak value, and is set to 0 as an initial value. Therefore, the peak value αpeak is sequentially updated to the value of the rotational angular acceleration α while the rotational angular acceleration α rises until it reaches the peak, and the rotational angular acceleration α is fixed as the peak value αpeak when the rotational angular acceleration α reaches the peak. When the peak value αpeak is set in this way, a process of setting the upper limit value of the torque that can be output from the motor 22 in order to suppress occurrence of slipping based on the peak value αpeak is performed (step S204 ). This processing is performed using the graph shown in FIG. 6 in the embodiment. FIG. 6 is a graph showing the relationship between rotational angular acceleration α and torque upper limit Tmax. In this graph, as illustrated, there is a characteristic that the torque upper limit Tmax becomes smaller as the rotational angular acceleration α increases. Therefore, the greater the rotational angular acceleration α peak value αpeak becomes, that is, the greater the degree of slippage, the smaller the value is set as the torque upper limit Tmax, thereby limiting the output from the motor 22 to a corresponding extent. torque.

In this way, after the torque upper limit Tmax is set, then, it is determined whether the execution of the processing program when the slip occurs is the first execution (step S206), and if it is determined to be the first execution, the following processing is performed, that is, for The adjustment rotation is set as a lower limit value when the required torque Td* of the drive shaft 28 is limited by the set torque upper limit value Tmax to suppress a sudden limitation of the torque output to the drive shaft 28. Adjustment torque setting process of torque value TL (step S208). The adjustment torque setting processing is executed by the adjustment torque setting processing program illustrated in FIG. 7 . Hereinafter, this adjustment torque setting process will be described.

When the adjustment torque setting processing routine is started, the CPU 72 of the electronic control unit 70 first sets the slip occurrence torque Tmslip as the torque output to the drive shaft 28 at the time when slip occurs (step S250 ). The setting of the slip generation torque Tmslip, in the embodiment, is to use the previous target torque Tm* of the motor 22 set by steps S110 to S114 in the previous driving control program of FIG. 2 as the slip generation torque Tm*. Moment Tmslip is set.

Next, input the road surface gradient θgr from the gradient sensor 54 and the steering angle θst from the steering angle sensor 56 (step S252), according to the input road surface gradient θgr, steering angle θst and in step S100 of the drive control program of FIG. 2 The input vehicle speed V is judged whether it is in the prescribed turning process (step S254), whether the road surface gradient θgr is a slope and the vehicle speed V is an extremely low vehicle speed (step S256), and whether the road surface gradient θgr is It is determined that the road surface is flat (flat road) and the vehicle speed V is low (step S260). Here, the determination of whether the vehicle is in the predetermined turning process is performed, for example, by determining whether the vehicle speed V and the steering angle θst belong to the predetermined turning region, which is a region in which the steering angle θst is relatively large and the vehicle speed V is also high. An example of a graph used for this determination is shown in FIG. 8 . In addition, the determination of whether the road surface gradient θgr is a slope and the vehicle speed V is an extremely low vehicle speed is determined by determining whether the road surface gradient θgr is at or above a predetermined gradient (for example, a gradient of about 14% or 15%) and whether the vehicle speed V is less than a specified The vehicle speed (for example, the vehicle speed of about 5-10km/h) is carried out. and then. Whether the road surface gradient θgr is a flat road surface and the vehicle speed V is a low vehicle speed is determined by determining whether the road surface gradient θgr is less than a prescribed gradient (for example, a gradient of about 3% or 5%) and whether the vehicle speed V is less than a prescribed vehicle speed (for example, 20~ 30km/h or so) to carry out.

As a result of such determination, it is determined that the vehicle is in a predetermined turning process, or when it is determined that the road surface gradient θgr is a slope and the vehicle speed V is an extremely low vehicle speed, it is determined that the vehicle is in a relatively unstable state when slipping occurs, It is necessary to give priority to the rapid convergence of the slip rather than to moderate the shock by suppressing the sharp limitation of the required torque, and the adjustment when the slip convergence is prioritized is set based on the slip generation torque Tmslip input in step S250 Torque TL (step S258); When it is determined that the conditions of steps S254 and S256 are not met but the road surface gradient θgr is a flat road surface and the vehicle speed V is a low vehicle speed, it is judged that the vehicle when slipping occurs is in a relatively stable state. The rapid convergence of the slip is more important than the need to suppress the sharp limit of the required torque Td* to alleviate the shock. When the priority of shock relief is set based on the slip occurrence torque Tmslip input in step S250 Adjust the torque TL (step S262), when it is determined that it does not meet any one of the conditions of steps S254, S256, and S260, it will balance the rapid convergence of the slip and the relaxation of the impact, according to the step S250. The input slip generation torque Tmslip is used to set the normal adjustment torque TL (step S264), and this routine ends. The setting of such an adjustment torque is performed in advance by making a table of the relationship between the torque Tmslip at the time of slipping and the adjustment torque TL and storing it in the ROM 74 in advance in the embodiment. When the torque Tmslip at the time of slipping is given, , which is set by deriving the corresponding adjustment torque TL from the graph. An example of this graph is shown in FIG. 9 . As shown in the figure, the adjustment torque TL when the slip convergence is prioritized is set to be larger than the normal time, and the adjustment torque TL is set to be smaller when the shock relaxation is prioritized than the normal time.

Returning to the processing program when slipping occurs in Fig. 5, after the adjustment torque TL is set, it is determined whether the set adjustment torque TL is larger than the torque upper limit Tmax set in step S204 (step S210 ), when it is determined that the adjusted torque TL is larger than the torque upper limit Tmax, the torque upper limit Tmax is adjusted so that the adjusted torque TL is adjusted (step S212). Then, the required torque Td* set in step S102 of the drive control program in FIG. The smaller one of the limit values Tmax is set as the target torque Tm* of the motor 22 (step S214), and this routine is ended. Thus, when the adjustment torque TL is larger than the torque upper limit Tmax, the torque upper limit Tmax set to suppress slipping is adjusted to the adjustment torque TL to limit the required torque Td* Therefore, the sudden limitation of the required torque Td* can be suppressed, and a torque shock that may occur when the motor 22 is driven and controlled can be prevented. At this time, the adjustment torque TL is set when it is determined that the vehicle is traveling at a predetermined turn, or that the vehicle is traveling at a very low speed on a slope, and it is determined that the vehicle is in a relatively unstable state. A value smaller than usual is used to give priority to rapid convergence of slippage; when it is determined that the vehicle is traveling on a flat road at a low speed rather than a prescribed turn, it is set to be larger than usual Therefore, while ensuring the running stability of the vehicle, it is possible to effectively alleviate the torque shock accompanying the suppression of slip.

When the slip occurrence processing is repeatedly executed, and it is determined in step S206 that the slip occurrence processing is not performed for the first time, a process of updating the adjustment torque TL set in step S208 is performed (step S216 ). In the process of updating the adjustment torque TL, in the embodiment, the value obtained by subtracting the predetermined value Trate from the previously set or updated adjustment torque TL (previous TL) is used as the new adjustment torque TL. And set it again. After the adjustment torque TL is updated, when the updated adjustment torque TL is larger than the torque upper limit Tmax, the updated adjustment torque TL is adjusted as the torque upper limit Tmax (steps S210, S212) , and set the smaller one of the required torque Td*, the torque upper limit Tmax set in step S204, or the adjusted torque upper limit Tmax in step S212 as the target of the motor 22 Processing of torque Tm* (step S214), and then this routine ends.

The slip-convergence processing is processing for releasing (relaxing) the limitation imposed on the required torque Td* during slip that occurs during the convergence, and is executed by the slip-convergence processing routine in FIG. 10 . When the slipping convergence processing program is started, the CPU 72 of the electronic control unit 70 first multiplies the slip generation torque Tmslip set in the adjustment torque setting processing program of FIG. 7 by a predetermined coefficient K to set the torque. Torque upper limit Tmax (step S300), and carry out the process of using the set torque upper limit Tmax to protect the required torque Td* set in step S102 of the drive control program of Fig. 2 (step S302 ). Here, the coefficient K is set within a range of 0 to 1 in order to prevent re-slip. Then, it is determined whether or not a predetermined time has elapsed since the first execution of the slipping convergence processing program was started (step S304 ). When it is determined that the predetermined time has not passed, this routine is directly terminated; when it is determined that the predetermined time has passed, the process of setting both the slipping generation flag F1 and the slipping convergence flag F2 to 0 values is performed (step S306), and then the end this program. Therefore, until a predetermined time elapses after the initial execution of the slipping convergence processing program, the required torque Td* is limited at a predetermined ratio of the torque (Tmslip·K) output to the drive shaft 28 when slipping occurs. , when the predetermined time has elapsed, the restriction by the torque upper limit value Tmax is completely released, the required torque Td* is set as the target torque Tm* of the motor 22, and then the motor 22 is driven and controlled.

In FIG. 11 , there is shown an explanatory diagram for explaining the time change state of the target torque Tm* and the rotational angular acceleration α of the drive shaft 28 when the torque output to the drive shaft 28 is limited due to the occurrence of slip. . When the rotational angular acceleration α of the drive shaft 28 exceeds the threshold value αslip at time t1 and slip occurs, the torque upper limit Tmax is set corresponding to the rotational angular acceleration α. At this time, in order to alleviate the shock caused by the sudden restriction of the torque on the drive shaft 28 due to the torque upper limit Tmax, the vehicle is more stable according to the steering amount θst of the vehicle, the road surface gradient θgr, and the vehicle speed V. The tendency is to give priority to the relaxation of the shock, and set a larger value as the adjustment torque TL. When the adjustment torque TL is larger than the torque upper limit Tmax, the set torque upper limit The value Tmax is adjusted to set the torque TL. At time t2 immediately after the occurrence of slip, the target torque Tm* of the motor 22 is set so as to be limited to the adjustment torque TL. Thereafter, the set adjustment torque TL is gradually updated to a smaller value, and the torque output to the drive shaft 28 is limited up to the torque upper limit value Tmax corresponding to the peak value of the rotational angular acceleration α. At time t3 when a predetermined time has elapsed after the rotational angular acceleration α has decreased to a negative value due to torque limitation, it is determined that the slip has converged, and the limitation of the torque output to the drive shaft 28 is released.

According to the automobile 20 of the embodiment described above, the torque upper limit value Tmax set in order to suppress the slip is adjusted so that it becomes smaller as the running state of the vehicle tends to be unstable. If the torque TL is still small, the adjusted torque TL is readjusted as the torque upper limit Tmax, and the required torque Td* to be output to the drive shaft 28 is limited so that it reaches the adjusted torque upper limit. Tmax or below. That is, when the running state of the vehicle is in a relatively unstable state when slipping occurs, the rapid convergence of slipping is given priority; when the running state of the vehicle is in a relatively stable state when slipping occurs, the mitigation of impact is given priority; , it is possible to effectively alleviate the shock accompanying the suppression of slippage while ensuring the running stability of the vehicle.

In the automobile 20 of the embodiment, the torque upper limit Tmax is adjusted by selecting one of the three types of adjustment torque TL (slip and convergence priority, normal time, and shock relaxation priority) according to the running state of the vehicle. However, it is also possible to adjust the torque upper limit Tmax by selecting one of two or four or more adjustment torques TL according to the running state of the vehicle.

In the automobile 20 of the embodiment, in the process of step S254 of the adjustment torque setting process routine in FIG. It is assumed that whether or not the steering angle of the vehicle is at or above a predetermined steering angle is determined based on only the steering angle θst.

In the automobile 20 of the embodiment, in the processing of step S256 of the adjustment torque setting processing routine of FIG. However, regardless of the vehicle speed V, the adjustment torque TL at the time of slipping convergence priority may be set when the road surface gradient θgr is at or above a predetermined gradient regarded as a slope. In the process of step S258, when the road surface gradient θgr is a flat road surface and the vehicle speed V is a low vehicle speed, the adjustment torque TL at the time of giving priority to shock mitigation is set, but it may be set to be When the road surface gradient θgr is less than the predetermined gradient considered as a flat road surface, the adjustment torque TL at the time of prioritizing shock mitigation is set.

In the automobile 20 of the embodiment, although it is assumed that in step S254 of the trimming torque setting processing program in FIG. However, the determination may be made by estimating the steering angle θst based on the deviation of the rotational speeds Nr, N1 of the non-driven wheels 64a, 64b detected by the wheel speed sensors 36a, 36b, and using the estimated steering angle θst to determine whether the vehicle is within a predetermined value. determination during steering.

In the automobile 20 of the embodiment, although it is assumed that in steps S256 and S260 of the adjustment torque setting processing program in FIG. For the determination of a flat road surface, it is also possible to estimate the road surface gradient θgr based on the relationship between the torque output to the drive shaft 28 and the acceleration of the vehicle during driving or to stop the process, or to estimate the road surface gradient θgr along the direction of the road surface gradient θgr because of the road surface gradient θgr. The force acting on the vehicle is determined using the estimated road surface gradient θgr or the force acting on the vehicle due to the road surface gradient θgr to determine whether the road surface is a slope or a flat road surface.

In the automobile 20 of the embodiment, although the torque upper limit Tmax is derived from the rotational angular acceleration α and the adjustment torque TL is derived from the running state of the vehicle at the same time, the adjustment torque TL is larger than the torque upper limit Tmax At the time, the torque upper limit Tmax is adjusted so as to become the adjusted torque TL, thereby restricting the required torque Td*, but it is also possible to directly derive the estimated and The torque upper limit Tmax of the element corresponding to the torque TL is adjusted.

In the embodiment, although the description is applied to the automobile 20 provided with the mechanically connected motor 22 capable of directly outputting power to the drive shaft connected to the drive wheels 62a, 62b, as long as it is equipped with The motor vehicle that outputs power may be applied to vehicles of any structure. For example, it is applicable to a so-called series-type hybrid vehicle (series hybrid vehicle) that includes an engine, a generator connected to an output shaft of the engine, and a motor that outputs power to a drive shaft using the generated power from the generator. . In addition, as shown in FIG. 12 , it is also applicable to include an engine 122 , a planetary gear 126 connected to the engine 122 , a motor 124 capable of generating electricity connected to the planetary gear 126 , and a motor 124 connected to the planetary gear 126 simultaneously. A so-called mechanical distribution hybrid vehicle (mechanical distribution hybrid vehicle) 120 that can output power to the drive shaft connected to the drive wheels 62a, 62b and is mechanically connected to the motor 22 on the drive shaft; as shown in Figure 13 As shown, it is also applicable to have an inner rotor 224a connected to the output shaft of the engine 222 and an outer rotor 224b installed on the drive shaft connected to the drive wheels 62a, 62b, and through the inner rotor 224a and the outer rotor 224b A motor 224 that rotates relatively due to the action of electromagnetic force, and a motor 22 that can output power to the drive shaft and is mechanically connected to the drive shaft, the so-called electric distribution hybrid vehicle (electric distribution hybrid vehicle) 220 . Alternatively, as shown in FIG. 14, it is also applicable to include the motor 22 connected to the drive shaft connected to the drive wheels 62a, 62b via a transmission 324 (continuously variable transmission or a poled automatic transmission, etc.), and the motor 22 connected to the drive shaft via the clutch CL. A hybrid vehicle (combined vehicle) 320 is an engine 322 connected to the rotating shaft of the motor 22 . At this time, as the control when slipping occurs on the driving wheel, in consideration of the speed of the output responsiveness of the control, etc., the torque output to the driving shaft is mainly controlled by controlling the motor mechanically connected to the driving shaft. However, it is also possible to control other electric machines or to control the motor in coordination with the control of this electric machine.

As mentioned above, although the embodiment of this invention was demonstrated using an Example, this invention is not limited by such Example at all, It is obvious that it can be implemented in various forms in the range which does not deviate from the gist of this invention.

Claims (10)

1. A vehicle comprising a motor capable of outputting power to a drive shaft connected to a drive wheel, characterized in that: Slip detection means for detecting slippage caused by idling of the above-mentioned drive wheels; A running state detection device that detects at least one of a steering amount of the vehicle and a road surface gradient as the running state of the vehicle; When slipping is detected by the slip detection device, based on at least one of the steering amount of the vehicle detected as the travel state of the vehicle by the travel state detection device and the road surface gradient, a setting is set as a sharp limit to the above-mentioned a sharp restriction suppression degree setting device for the degree of rapid restriction suppression to the extent when the torque output by the drive shaft is suppressed; and A control device for driving and controlling the electric motor so as to limit the torque output to the drive shaft by the set sudden limit suppression degree. 2. The vehicle according to claim 1, wherein said driving state detection device is a device having a vehicle speed detection device for detecting the speed of said vehicle; The abrupt restriction suppression degree setting means is a device for setting the abrupt restriction suppression degree based on the detected steering amount of the vehicle and the detected vehicle speed. 3. The vehicle according to claim 2, wherein said abrupt limit suppression degree setting means is configured to change the steering amount of said detected vehicle and said detected vehicle speed of the vehicle to a predetermined turning range. A device that sets the above-mentioned sharp limit suppression degree in a way that is smaller than usual. 4. The vehicle according to claim 1, wherein said driving state detection device is a device having a vehicle speed detection device for detecting the speed of said vehicle; The abrupt restriction suppression degree setting means is a device for setting the abrupt restriction suppression degree based on the detected road surface gradient and the detected vehicle speed. 5. The vehicle according to claim 4, wherein said abrupt restriction suppression degree setting means is configured to be used when said detected road gradient is greater than or equal to a first prescribed gradient and said detected vehicle speed is less than a first prescribed vehicle speed. , the means for setting the above-mentioned sharp limit suppression degree so as to become smaller than usual. 6. The vehicle according to claim 4, wherein said abrupt restriction suppression degree setting means is configured to: A device that sets the above-mentioned sharp limit suppression degree so as to become larger than usual. 7. The vehicle according to claim 5, wherein said abrupt restriction suppression degree setting means is configured to: A device that sets the above-mentioned sharp limit suppression degree so as to become larger than usual. 8. The vehicle according to claim 1, further comprising a rotational acceleration detection device for detecting the rotational acceleration of the drive shaft; The control device is configured to limit the demand of the drive shaft by the torque limit value set based on the detected rotational angular acceleration of the drive shaft when the slip is detected by the slip detection device. The lower limit value of the torque is used as the degree of suppression of the sudden limit, and the device for controlling the driving of the electric motor is used to limit the torque output to the drive shaft. 9. The vehicle according to claim 1, wherein said electric motor is one electric motor commonly used for left and right wheels as said drive wheels. 10. A control method for a vehicle comprising a motor capable of outputting power to a drive shaft connected to drive wheels, characterized in that it comprises: (a) the step of detecting slippage caused by the idle rotation of the above-mentioned drive wheels; (b) a step of detecting at least one of a steering amount of the vehicle and a road gradient as the running state of the vehicle; (c) When skidding is detected in the above step (a), based on at least one of the amount of steering of the vehicle detected as the running state of the vehicle in the above step (b) and the gradient of the road surface, set the a step of rapidly limiting the degree of suppression to the extent that the torque output to the drive shaft is suppressed; and (d) A step of driving and controlling the electric motor so as to limit the torque output to the drive shaft according to the set sudden restriction suppression degree.

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