JP2005261015A - Drive controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive controller of an electric vehicle capable of preventing slip down of a vehicle on a slope and applicable even to an electric vehicle having no brake detection means. <P>SOLUTION: The drive controller of an electric vehicle comprises a means (11) for detecting the r.p.m. of a travel motor (1), a means (42) for calculating acceleration (G) from the r.p.m. of the travel motor, a means (12) for detecting shift position, a means (43) for judging slip down of a vehicle depending on the shift position and acceleration, a means (46) calculating a holding torque (T) for suppressing slip down of the vehicle depending on the acceleration calculated by the acceleration calculating means, a means (45) for calculating acceleration torque (Ta) depending on the accelerator opening (K), and a means (47) for comparing the acceleration torque with the holding torque and selecting any one torque and then calculating a drive torque command (Tc) for the travel motor based on the selected torque. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric vehicle using an electric motor as a drive source, and more particularly to a drive control device for an electric vehicle that prevents the vehicle from sliding down a slope.

  For an AT vehicle equipped with an automatic transmission, the engine speed and output are controlled so that, for example, the gradient load of the vehicle and the output torque of the torque converter are balanced when stopping on an uphill road. There is one that keeps the vehicle stopped even if it is not stepped on. In this regard, in an electric vehicle, in order to maintain the vehicle in a stopped state on a slope due to the reason that such engine control cannot be performed, the brake pedal must be depressed, and when starting the vehicle from this stopped state When switching from the brake pedal to the accelerator pedal, there arises a disadvantage that the vehicle slides down. That is, when the pedal is changed, the vehicle moves backward on the uphill road, and the vehicle moves forward on the downhill road.

Therefore, in the driving force control device for an electric vehicle described in Patent Document 1, when the vehicle is stopped on an uphill, the braking force by the brake pedal is detected, and the brake operation is released when the vehicle starts from this stopped state. In addition, the torque of the electric motor is controlled according to the braking force so that the vehicle speed becomes zero, thereby preventing the vehicle from retreating when the brake pedal is switched to the accelerator pedal.
JP-A-6-261417

The driving force control device for an electric vehicle described in Patent Document 1 detects the braking force and controls the torque of the motor in order to prevent the vehicle from retreating when starting from a stopped state on an uphill road. In addition, since a detecting means for detecting the braking force is indispensable, it cannot be applied to an electric vehicle having no braking force detecting means.
An object of the present invention is to provide an electric vehicle drive control device that can be applied to an electric vehicle that does not include a brake detection unit and that can prevent the vehicle from sliding down on a slope.

  To achieve the above object, the electric vehicle drive control device according to the first aspect of the present invention calculates the acceleration by the acceleration calculating means from the rotational speed of the traveling motor detected by the motor rotational speed detecting means, and this calculation is performed. The suppression torque for suppressing the slip of the electric vehicle is calculated by the suppression calculation means according to the acceleration, and the drive torque command for the driving motor is calculated by the drive torque calculation means based on the suppression torque. It has become.

  In the present invention, the drive torque command is calculated based on the suppression torque calculated according to the acceleration calculated from the rotation speed of the traveling motor. When the driving motor is driven and controlled based on this drive torque command, the electric vehicle that is stopped on the slope is prevented from slipping down (the vehicle goes backward on the uphill road and moves forward on the downhill road when starting from the stopped state). Is done. In the present invention, the suppression torque for suppressing the vehicle slippage is calculated according to the acceleration calculated from the rotational speed of the traveling motor, and the detection means related to the suppression torque calculation is traveling. It is only necessary to provide motor rotation number detecting means for detecting the rotation number of the motor for use, and it is not necessary to provide brake force detecting means for detecting the braking force. That is, the present invention can be applied to an electric vehicle that does not have a braking force detection means, and can prevent such a vehicle from falling down.

According to a second aspect of the present invention, there is provided a drive control device for an electric vehicle, wherein the electric vehicle drive control device determines whether the electric vehicle slides in accordance with the shift position detected by the shift position detection means and the acceleration calculated by the acceleration calculation means. Means.
In the invention according to claim 2, the slippage is accurately determined according to the shift position and the acceleration. That is, the slope is roughly divided into an uphill road and a downhill road. Generally, the shift position when stopping on the uphill road is the D range, and the shift position when stopping on the downhill road is the R range. Based on the acceleration, it is possible to accurately determine both vehicle downhill (backward) on the uphill road and downhill (forward) on the downhill road.

  In the present invention, an accelerator torque calculating means for calculating an accelerator torque according to the accelerator opening is provided, and the driving torque calculating means calculates the accelerator torque calculated by the accelerator torque calculating means and the restraining torque calculated by the restraining torque calculating means. And driving torque command for the driving motor may be calculated on the basis of the selected torque, so that the motor drive control at the time of start from the stop state on the slope Can be performed more appropriately.

  Further, the slip determining means may calculate the speed from the rotational speed of the traveling motor detected by the motor rotational speed detecting means, and determine the slip according to the shift position, speed and acceleration. Therefore, it is possible to accurately and simply perform the sliding determination and the motor torque control.

  According to the first aspect of the present invention, the drive torque command is calculated based on the inhibition torque calculated according to the acceleration calculated from the rotation speed of the travel motor. Therefore, the drive motor is driven and controlled based on the drive torque command. By doing so, it is possible to prevent a vehicle that is stopped on a hill from slipping down, and it is only necessary to provide a motor rotation speed detection means in connection with the calculation of the suppression torque. It can also be applied to automobiles.

  According to the second aspect of the present invention, it is possible to accurately determine the downhill of the vehicle on the uphill road and the downhill road according to the shift position and the acceleration.

Hereinafter, a drive control device for an electric vehicle according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a traveling motor 1 connected to left and right drive wheels 2 is mounted on an electric vehicle (hereinafter referred to as a vehicle). This traveling motor 1 is connected to an electronic control unit 4 that forms the main part of the drive control device via a power conversion device 4, and is driven and driven by electric power from a battery 5 under the control of the electronic control unit 4. The vehicle is driven by rotating the wheel 2.

The electronic control unit 4 includes a motor speed detecting means 1 for detecting the speed of the traveling motor 1, a shift position detecting means 12 for detecting a shift position of a shift lever (not shown), and an accelerator for detecting an accelerator opening K. The opening degree detection means 13 is connected.
The electronic control unit 4 calculates the motor rotation speed (more generally, the speed (vehicle speed)) V from the motor rotation speed detected by the motor rotation speed detection means 11 and the speed calculation means 41. Acceleration calculation means 42 for calculating motor rotation acceleration G (more generally, acceleration from the motor rotation speed detected by motor rotation speed detection means 11) G from shift motor rotation speed V, shift position detection means 12, speed And a slip-down determination means 43 that determines whether the vehicle slips in accordance with the shift position, speed V, and acceleration G detected or calculated by the calculation means 41 and the acceleration calculation means 42, respectively.

  The electronic control unit 4 is also detected by the creep torque calculating means 44 for calculating the creep torque Tcr from the shift position and speed V detected by the shift position detecting means 12 and the speed detecting means 41, respectively, and by the accelerator opening detecting means 13. Accelerator torque calculating means 45 for calculating accelerator torque Ta from the calculated accelerator opening K and creep torque Tcr calculated by creep torque calculating means 44, and the vehicle sliding down according to acceleration G calculated by acceleration calculating means 42 The suppression torque calculation means 46 for calculating the suppression torque T for suppressing the acceleration torque, the accelerator torque Ta calculated by the accelerator torque calculation means 45 and the suppression torque T calculated by the suppression torque calculation means 46 are compared. Select one torque and select It was based on the torque to calculate the driving torque command Tc and a drive torque command calculation means 47 for outputting the electric power converter 3.

Hereinafter, motor drive control by the drive control apparatus having the above-described configuration will be described with reference to FIGS.
When the operating power supply is turned on, the electronic control unit 4 of the drive control device starts execution of the motor drive control routine shown in FIGS.
First, in the acceleration calculation routine shown in FIG. 2, required calculation processing (fail-safe processing, erroneous detection prevention processing, etc.) is performed on the accelerator opening data read from the accelerator opening detecting means 13 to the electronic control unit 4. Thus, the accelerator opening K is obtained (step S1). Next, the shift position data read from the shift position detection means 12 is subjected to a required calculation process to obtain a shift position (step S2), and the motor rotation speed data read from the motor rotation speed detection means 11 is obtained. Based on the above, the speed calculation means 41 calculates the speed V (step S3).

Next, the creep torque calculation means 44 calculates the creep torque Tcr from the map illustrated in FIG. 6 based on the shift position and speed V obtained in steps S2 and S3, respectively (step S4).
Here, the creep torque Tcr refers to the torque generated by the motor 1 even when the accelerator pedal is not depressed. In FIG. 6, the creep torque Tcr takes a positive value when the shift position is in the D range, and takes a negative value when the shift position is in the R range (in this embodiment, various parameters are positive in the vehicle forward direction). Take a negative value in the vehicle reverse direction). That is, a positive creep torque Tcr acting in the vehicle forward direction is generated on the uphill road where the shift position is generally in the D range to prevent the vehicle from retreating. On the downhill road where the shift position is in the R range, the vehicle reverse direction is used. A negative creep torque Tcr acting on the vehicle is generated to prevent the vehicle from moving forward. In the present invention, it is not essential to generate the creep torque Tcr.

  In the next step S5, the maximum accelerator torque Tmax obtained from the map illustrated in FIG. 7 based on the shift position and speed V obtained in steps S2 and S3, respectively, the accelerator opening K obtained in step S1, and the step Based on the creep torque Tcr obtained in S4, the accelerator torque Ta is calculated according to the following equation (1). In FIG. 7, the maximum accelerator torque Tmax takes a positive value in the D range, and takes a negative value in the R range.

Ta = K (Tmax−Tcr) + Tcr (1)
Next, the acceleration calculation means 42 determines the acceleration G. Therefore, the speed V (i) set as the current value in step S6 of the previous cycle is set as the previous value V (i-1) (step S6), and the speed V calculated in step S2 of the current cycle is the current value. It is set as the value V (i) (step S7). Here, the initial value of the speed value V (i) set in step S6 is zero. Next, by subtracting the previous value V (i−1) from the current value V (i), a speed change ΔV from the previous cycle to the current cycle is calculated (step S8), and this change ΔV is calculated as the control cycle ΔT. The acceleration G is calculated by dividing by (step S9).

When the acceleration calculation routine of FIG. 2 is completed, the routine proceeds to the slippage determination routine of FIG.
As shown in FIG. 8, in the slippage determination routine of this embodiment, the vehicle slippage is determined based on the sign of the vehicle speed V representing the moving direction of the vehicle and the sign of the acceleration G representing the acceleration direction of the vehicle. ing. Here, regarding the signs of acceleration G and vehicle speed V, the vehicle forward direction is positive and the vehicle reverse direction is negative.

  3 determines whether or not the shift position obtained in step S2 in FIG. 2 is in the D range (step S11). If the shift position is in the D range, both acceleration G and velocity V values are negative. Is determined (step S12). If the values of acceleration G and velocity V are not negative, it is determined whether or not the value of acceleration G is negative (step S13). If it is determined in step S11 that the range is not the D range, it is determined whether the range is the R range (step S14). If the range is the R range, whether the acceleration G and the speed V are both positive or not. Is determined (step S15), and if both the acceleration G and the velocity V are not positive, it is determined whether or not the acceleration G is positive (step S16).

  Then, the determination result in step S12 is affirmative, that is, the shift position is in the D range, the acceleration G and the speed V are both negative (third quadrant in FIG. 8), and the vehicle moves backward with acceleration in the reverse direction on the uphill road. If it is determined that the vehicle is moving backward on the uphill road, the vehicle is determined to be “increase in sliding”. In addition, the determination result in step S15 is affirmative, that is, the shift position is in the R range, the acceleration G and the speed V are both positive (first quadrant in FIG. 8), and the vehicle moves forward with acceleration in the forward direction on the downhill road. If it is determined that the vehicle is moving forward on the downhill road, it is determined that the vehicle is increasing in sliding (step S18).

  On the other hand, the determination result in step S13 is negative, that is, the shift position is in the D range, the acceleration G is positive or zero, and the speed V is negative, zero, or positive (first and second quadrants in FIG. 8). When the backward movement is weakened or the backward movement is stopped or the forward movement is strengthened, it is determined that “sliding is being resolved” because the sliding is being resolved (step S17). Further, when the determination result in step S16 is affirmative, that is, when the shift position is in the R range, the acceleration G is positive, and the speed V is negative (fourth quadrant in FIG. 8), the reverse slope is weakened. Since it can be determined that the vehicle has moved in the direction opposite to the sliding direction and the sliding has been eliminated, it is determined that the vehicle has been eliminated (step S17).

  If the determination result in step S13 is affirmative, that is, the shift position is in the D range, the acceleration G is negative, the speed V is positive (second quadrant in FIG. 8), and the advance on the uphill road is weakened, Since it can be determined that the vehicle has moved in the direction opposite to the sliding direction and the sliding has been eliminated, it is determined that the vehicle has been eliminated (step S19). Further, the determination result in step S16 is negative, that is, the shift position is in the R range, the acceleration G is negative or zero, and the speed V is positive or zero or negative (second and third quadrants in FIG. 8). If the forward movement is weakened or the forward / backward movement is stopped or the backward movement is strengthened, it is determined that “sliding is being eliminated” because the sliding is being eliminated (step S19).

If the determination in step S14 is negative, that is, if the shift position is neither the D range nor the R range, for example, in the parking range, it is determined that “sliding determination is not required” (step S20).
When the slippage determination routine of FIG. 3 ends, the process proceeds to the suppression torque calculation routine of FIG.

In the suppression torque calculation routine of this embodiment, the suppression torque T is calculated according to the following equation (2).
T = F (i) × R / Gr + Tcr (2)
Here, F (i) represents a driving force to be applied to the vehicle in this cycle, R is a tire dynamic weight radius, Gr is a reduction ratio in a reduction gear provided between the motor 1 and the drive wheel 2, and Tcr is creep. Torque.

The driving force F (i) is calculated for each case according to the four determination results (steps S17 to S20) in the sliding determination routine of FIG.
First, when it is determined in step S17 of the slip-down determination routine that “sliding-down is being resolved or resolved”, the driving force F (i) calculated in the previous cycle is set as the driving force F (i−1) in the previous cycle. (Step S31) Then, an addition F of the driving force to be added in this cycle to the driving force F (i-1) is calculated according to the following equation (3) (Step S32).

F = W × (−G) (3)
Here, W represents the vehicle weight, and G represents the acceleration calculated in step S9 in FIG. (-G) indicates that the added amount F acts in the direction opposite to the acceleration G of the vehicle.
In the next step S33, the sum of the driving force F (i-1) of the previous cycle set in step S31 and the addition F calculated in step S32 is obtained, and this sum (F (i-1) + F) and value are obtained. The larger of 0 is obtained as the driving force F (i) of the current cycle. The effect of selecting the larger of the sum and the value 0 will be described later.

  On the other hand, if it is determined in step S18 of the slip-down determination routine that “increase in the slip-down”, the driving force F (i−1) of the previous cycle is set (step S34), and according to the above equation (3). The addition F of the current cycle is calculated (step S35), and the addition F calculated in step S35 is added to the driving force F (i-1) of the previous cycle set in step S34 to drive the driving force F ( i) is obtained (step S36). That is, if the sliding-down increases, the driving force F (i) and thus the suppression torque T is increased.

  If it is determined in step S19 of the slippage determination routine that “sliding is eliminated or being resolved”, the driving force F (i−1) of the previous cycle is set (step S37), and this time according to equation (3). The period addition F is calculated (step S38), the sum of the driving force F (i-1) and the addition F in the previous period is obtained, and the sum (F (i-1) + F) and value 0 Is determined as the driving force F (i) of the current cycle (step S39). The effect of selecting the smaller of the sum and the value 0 will be described later.

  If it is determined in step S20 of the sliding determination routine that “sliding determination is not required”, the driving force F (i−1) of the previous cycle is set (step S40), and the value 0 is driven in the current cycle. The force F (i) is set (step S41). That is, if it is not necessary to determine the downhill, the driving force F (i-1) is stored for calculating the suppression torque in the next cycle and the current driving force F (i) is set to zero, and the current cycle is suppressed. The torque T is made equivalent to the creep torque Tcr.

When the driving force F (i) of the current cycle is obtained in any of the above steps S33, S36, S39 or S41, the above formula (2) is obtained based on the driving force F (i) of the current cycle. The suppression torque T is calculated (step S42).
When the suppression torque calculation routine of FIG. 4 ends, the process proceeds to the drive torque command calculation routine of FIG.

  In the drive torque command calculation routine, it is first determined whether or not the shift position is in the D range (step S51). If the shift position is in the D range, the suppression torque T calculated in step S42 of the suppression torque calculation routine of FIG. The larger one of the accelerator torques Ta calculated in step S5 of the acceleration calculation routine of FIG. 2 is selected as the drive torque command Tc for the current cycle (step S52).

  If it is determined in step S51 that the shift position is not in the D range, it is determined whether or not the shift position is in the R range (step S53). If the shift position is in the R range, the suppression calculated by the suppression torque calculation routine is determined. The smaller one of the torque T and the accelerator torque Ta calculated by the acceleration calculation routine is selected as the drive torque command Tc of the current cycle (step S54).

On the other hand, if it is determined in step S53 that the shift position is not in the R range, that is, if the shift position is not in the D range or the R range, the value 0 is set as the drive torque command Tc for the current cycle (step S55).
As described above, the acceleration G is calculated by the acceleration calculation routine of FIG. 2, and the slippage determination routine of FIG. 3 determines the vehicle slippage based on the shift position, the sign of the vehicle speed V, and the sign of the acceleration G, In the suppression torque calculation routine of FIG. 4, the driving force F (i) of the current cycle obtained based on the driving force F (i−1) of the previous cycle and the added amount F according to the calculation formula corresponding to the result of the slippage determination. Then, the suppression torque T is calculated. Then, in the drive torque command calculation routine of FIG. 5, the drive torque command Tc is obtained based on the shift position, the suppression torque T, and the accelerator torque Ta. Hereinafter, the above control flow will be described more specifically.

First, motor drive control at the time of starting from a stop state on an uphill road will be described.
While the vehicle is stopped on an uphill road, the shift position is generally in the D range. When the brake pedal force is weakened in this stopped state, for example, for starting, the vehicle starts to reverse at an acceleration G corresponding to the gradient of the uphill road and the vehicle weight.
In this case, since the signs of the acceleration G and the speed V are negative, it is determined as “increase in the slip” in step S18 of the slip determination routine (FIG. 3), and in step S35 of the suppression torque calculation routine (FIG. 4). The addition F of the driving force is calculated according to the above equation (3). Here, since the sign of the second operand (−G) in Expression (3) is positive, the sign of the addition F is positive, and accordingly, the driving force of the current cycle calculated in the next step S36. F (i) increases by the added amount F. As a result, the driving force acting in the vehicle forward direction is strengthened, the restraining torque T acting in the vehicle forward direction is increased, and the backward movement (sliding down) of the vehicle on the uphill road is suppressed.

  As described above, when the restraint torque T is used to suppress the vehicle from sliding down, the backward movement of the vehicle is weakened, and further, the backward movement of the vehicle is stopped and the forward movement of the vehicle is strengthened. In this case, since the sign of the acceleration G is positive or zero and the sign of the speed V is negative or zero or positive, it is determined that the slip is being resolved in step S17 of the slip determination routine, and the step of the suppression torque calculation routine is determined. In S32, a driving force addition F is calculated. Here, since the sign of the second operand (−G) in Expression (3) is negative, the sign of the driving force addition F is negative, or because the acceleration G is zero, the addition F is The sum of the driving force F (i−1) and the addition F in the previous cycle calculated in step S32 is reduced by the addition F or equal to the driving force F (i−1). In step S33, the larger one of the sum (F (i-1) + F) and the value 0 is obtained as the driving force F (i) of the current cycle, so that the vehicle moves forward to prevent the vehicle from moving backward on the uphill road The driving force applied in the direction is maintained or gradually decreased to the lower limit value 0, and accordingly, the suppression torque T is maintained or gradually decreased to the creep torque Tcr.

  Then, when the forward movement of the vehicle on the uphill road is weakened along with the gradual decrease of the suppression torque T, the acceleration G becomes negative and the speed V becomes positive. In step S38 of the torque calculation routine, the driving force addition F is calculated. Here, since the sign of the second operand (−G) in Expression (3) becomes positive, the sign of the driving force addition F calculated in step S38 becomes positive and is calculated in step S39. Since the sum (F (i-1) + F) increases by the added amount F, the positive driving force acting in the vehicle forward direction tends to increase, but in the next step S39, the sum (F (i-1) Since a value 0 smaller than + F) is selected as the driving force F (i) for the current cycle, the driving force F (i) for the current cycle is zero, and the suppression torque T is equivalent to the creep torque Tcr.

  FIG. 9 shows changes in suppression torque T and acceleration G with the passage of time when starting from a stop state on an uphill road. In FIG. 9, when negative acceleration G is generated as the vehicle moves backward, positive suppression torque T acting in the vehicle forward direction is generated. Thereafter, when acceleration G becomes zero, suppression torque T is maintained, and acceleration G is When it becomes positive, the suppression torque T gradually decreases, and then the suppression torque T becomes equivalent to the creep torque Tcr (zero in FIG. 9).

  When the above-described sliding down is suppressed, the second operand (−G) in the formula (3) has the same magnitude and the opposite sign as the acceleration G representing the degree of sliding down. F and thus the driving force F (i) and further the suppression torque T are optimized. As a result, the slippage of the vehicle can be quickly and smoothly eliminated without causing a delay in canceling the slippage when the added amount F is excessively small or causing control hunting when the added amount F is excessively large.

  Since the shift position is in the D range, the larger of the suppression torque T calculated as described above and the accelerator torque Ta calculated in step S5 of the acceleration calculation routine of FIG. Calculated as the command Tc. FIG. 10 shows changes in suppression torque T, accelerator torque Ta, and drive torque command Tc over time. In general, when starting from a stop on an uphill road, the brake pedal is switched to the accelerator pedal, and when the brake pedal depressing force is reduced, a restraining torque T is generated. Ta is generated. Therefore, initially, the suppression torque T is sent from the electronic control unit 4 to the motor 1 via the power converter 3 as a drive torque command Tc. Thereafter, when the accelerator torque Ta exceeds the suppression torque T, the accelerator torque Ta is sent out as a drive torque command Tc. In this way, since the drive torque command Tc smoothly transitions from the suppression torque T to the accelerator torque Ta, the vehicle that has stopped on the uphill road starts smoothly without sliding down.

Next, motor drive control at the time of starting from a stop state on a downhill road will be described.
While the vehicle is stopped on a downhill road, the shift position is generally in the R range. When the brake pedal is depressed in this stopped state, for example, to start, the vehicle starts to move forward with an acceleration G corresponding to the slope of the uphill road and the vehicle weight.
In this case, since the signs of the acceleration G and the speed V become positive, it is determined that the slip is increasing in step S18 of the slip determination routine (FIG. 3), and in step S35 of the suppression torque calculation routine (FIG. 4). The addition F of the driving force is calculated according to the above equation (3). Here, since the sign of the second operand (−G) in the expression (3) becomes negative and the sign of the addition F becomes negative, the driving force F (( i) decreases by the addition F. As a result, the driving force acting in the vehicle reverse direction is strengthened, the restraining torque T acting in the vehicle reverse direction is increased, and the forward movement (sliding down) of the vehicle on the downhill road is suppressed.

  As described above, when the vehicle slip is suppressed by the suppression torque T, the forward movement of the vehicle is weakened, and further, the forward movement of the vehicle is stopped and the vehicle is moved backward. In this case, since the acceleration G is negative or zero and the sign of the speed V is negative, zero, or positive, it is determined in step S19 of the slip determination routine that “sliding is being eliminated”, and in step S38 of the suppression torque calculation routine. An addition F of the driving force is calculated. Here, since the sign of the second operand (−G) in equation (3) is positive, the sign of the driving force addition F calculated in step S38 is positive, or the acceleration G is zero. As a result, the addition F becomes zero, and the sum (F (i-1) + F) calculated in step S39 is maintained at the same value as the previous value or increases by the addition F, so that it acts in the vehicle reverse direction. Negative driving force is maintained or reduced. In step S39, a value 0 smaller than the sum (F (i-1) + F) is selected as the driving force F (i) for the current cycle, so that the vehicle is prevented from moving forward on the downhill road. The driving force applied in the reverse direction is maintained or gradually decreased to the lower limit value 0, and accordingly, the suppression torque T acting in the vehicle reverse direction is maintained or gradually decreased to the creep torque Tcr.

  Then, if the reverse of the vehicle on the downhill road is weakened as the suppression torque T gradually decreases, the acceleration G becomes positive and the speed V becomes negative. In step S32 of the torque calculation routine, the driving force addition F is calculated. Here, since the sign of the second operand (−G) in Expression (3) is negative, the sign of the addition F of the driving force is negative, and the driving force F of the previous cycle calculated in step S32 is obtained. Since the sum of (i-1) and the added amount F decreases by the added amount F, the negative driving force acting in the vehicle reverse direction tends to increase, but in the next step S33, the sum (F (i-1 ) + F) and the larger value 0 are obtained as the driving force F (i) in the current cycle, so the driving force F (i) in the current cycle is zero, and the suppression torque T is equivalent to the creep torque Tcr. .

  Since the shift position is in the R range, the smaller of the suppression torque T calculated as described above and the accelerator torque Ta calculated in step S5 of the acceleration calculation routine of FIG. Calculated as the command Tc. Generally, when starting from a stop on a downhill road, the brake pedal is switched to the accelerator pedal, and when the brake pedal depressing force decreases, a negative deterrent torque T is generated. A positive accelerator torque Ta is generated. Therefore, initially, the suppression torque T is sent as the drive torque command Tc from the electronic control unit 4 to the motor 1 via the power converter 3, so that the vehicle is prevented from slipping when starting from a stop state on a downhill road. The

If the shift position is neither the D range nor the R range and “sliding determination is not required”, the driving force F (i) and the driving torque command Tc in the current cycle are set to zero in steps S41 and S55, respectively. . That is, motor drive control for preventing sliding down is not performed.
As described above, according to the drive control apparatus for an electric vehicle according to the present embodiment, the shift position detected by the shift position detector 12, the speed V calculated by the speed calculator 41, and the acceleration calculator 42 are used for calculation. In accordance with the acceleration G that has been made, it is possible to accurately determine the vehicle downhill (backward) on the uphill road and the downhill (forward) on the downhill road. Further, the accelerator torque calculated by the accelerator torque calculating means 45 in accordance with the restraining torque T calculated from the motor speed detected by the motor speed detecting means 11 or the accelerator opening K detected by the accelerator opening detecting means 13. Since either one of the torques Ta is selected as the drive torque command Tc, it is sufficient to provide the motor rotational speed detection means 11 essential for the electric vehicle in relation to the calculation of the suppression torque, and the electric vehicle not provided with the braking force detection means. It is possible to appropriately control the motor drive to prevent the vehicle from slipping down when starting the hill, to reduce the driver's operational burden when starting the hill, and from the time when the accelerator torque Ta exceeds the suppression torque Tc, the accelerator torque Since the motor is driven and controlled based on Ta, it is possible to smoothly start on a slope and improve driving feeling.

This is the end of the description of the embodiment of the present invention. However, the present invention is not limited to the above-described embodiment and can be variously modified.
For example, in the above embodiment, a constant may be used in place of the first operand W in the equation (3) used for calculating the driving force addition F. Further, a map created in advance may be used instead of the calculation based on the calculation formula (3).

In the present invention, it is not essential to select one of the torques as the drive torque command Tc for starting the vehicle according to the comparison result between the suppression torque Tc and the accelerator torque Ta. The suppression torque Tc may be used as the drive torque command Tc until a predetermined time has elapsed.
Moreover, the determination procedure in the sliding determination routine of FIG. 3 and the calculation procedure in the suppression torque calculation routine of FIG. 4 are examples, and are not limited to this. The same applies to other points.

1 is a schematic block diagram illustrating a drive control apparatus for an electric vehicle according to an embodiment of the present invention. 2 is a flowchart of an acceleration calculation routine executed for motor drive control by the electronic control unit shown in FIG. It is a flowchart of the slippage determination routine following the acceleration calculation routine. It is a flowchart of the suppression torque calculation routine following a sliding determination routine. It is a flowchart of the drive torque command calculation routine following a suppression torque calculation routine. It is a figure which shows an example of the map used for the creep torque calculation in an acceleration calculation routine. It is a figure which shows an example of the map used for the maximum accelerator torque calculation in an acceleration calculation routine. It is a figure which shows the down area | region in the down determination routine. It is a figure which shows the change of the suppression torque and acceleration with time passage at the time of the start from the stop state on an uphill road. It is a figure which shows the change of the suppression torque, accelerator torque, and drive torque instruction | command with progress of time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling motor 4 Electronic control unit 11 Motor rotation speed detection means 12 Shift position detection means 13 Accelerator opening degree detection means 41 Speed calculation means 42 Acceleration calculation means 43 Slip-down determination means 45 Accelerator torque calculation means 46 Inhibition torque calculation means 47 Drive Torque command calculation means

Claims (2)

Motor rotation number detecting means for detecting the rotation number of the traveling motor;
Acceleration calculating means for calculating an acceleration from the rotational speed of the traveling motor detected by the motor rotational speed detecting means;
A deterrence torque calculating unit that calculates a deterrence torque for suppressing the sliding of the electric vehicle according to the acceleration calculated by the acceleration calculation unit;
An electric vehicle drive control device comprising: drive torque calculation means for calculating a drive torque command for the traveling motor based on the suppression torque calculated by the suppression torque calculation means. Shift position detecting means for detecting the shift position;
2. The apparatus according to claim 1, further comprising: a slip-down determination unit that determines a slip-down of the electric vehicle according to the shift position detected by the shift position detection unit and the acceleration calculated by the acceleration calculation unit. Drive control device for electric vehicles.

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