JP2016013776A - Slip control device of electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip control device of an electric automobile which can detect a slip of a driving vehicle by detecting the inclination of a vehicle.SOLUTION: A slip control device 20 of an electric automobile includes: vehicle speed detecting means 18 for detecting vehicle speed; driven wheel rotation speed calculating means 19 for calculating the rotation speed of a driving wheel 7; and slip determining means 21 which compares the rotation speed of the driving wheel 7 with the vehicle speed, and determines that the driving wheel 7 slips when the rotation speed of the driving wheel 7 is larger than the vehicle speed. The slip determining means 21 is provided with vehicle angle detection means 25 which detecting inclined angles of front and rear parts of a vehicle from two air pressure sensors 28F and 28R respectively provided at the front and rear parts of the vehicle, and vehicle speed correcting means 24 which corrects the vehicle speed by using inclined angle/correction amount setting means 33 setting a relationship of the inclined angle and vehicle speed correction amount, from the detected inclined angles at the front and rear parts of the vehicle.

Description

  The present invention relates to a slip control device for an electric vehicle that can accurately determine whether or not a drive wheel has slipped from an inclination angle of the front and rear of the vehicle.

The following techniques have been proposed as techniques for performing vehicle slip control (traction control).
The engine output and the wheel braking force are limited so that the slip amount becomes a target slip amount corresponding to the friction coefficient of the road surface (Patent Document 1).
Drive wheel slip is detected by comparing the detected value of the angular acceleration of the drive wheel with a predetermined angular acceleration threshold (Patent Document 2).

JP-A-63-259141 JP-A-8-182119

  In an electric vehicle in which driving wheels are driven to rotate by an electric motor, torque applied to the driving wheels can be controlled by slip control. In the slip control algorithm, in order to detect wheel slip and take appropriate measures, for example, it is necessary to observe the following (1) to (4) independently.

(1) Vehicle speed (2) Acceleration (3) Wheel rotation speed (4) Road inclination

In the slip control, the rotational speed of the wheel is compared with the vehicle speed, and if the rotational speed of the wheel is higher than the vehicle speed, it is determined that the vehicle is slipping.
The acceleration can be calculated from the relationship between the driving force applied to the vehicle and the vehicle weight, and the vehicle speed can be obtained from the acceleration. However, on the uphill, the actual vehicle speed is lower than the vehicle speed assumed on the flat ground, so the rotational speed of the wheel is lower than the vehicle speed, and it is difficult to determine that the vehicle is slipping. Therefore, on the uphill, even if slipping, control such as limiting the torque to a small value is delayed.

  On the downhill, on the other hand, the actual vehicle speed is higher than the vehicle speed assumed on the flat ground, so the rotational speed of the wheels is higher than the vehicle speed, and it is easy to determine that the vehicle is slipping. For this reason, it is determined that the slip has not occurred on the downhill, but the torque is erroneously limited to be small.

  The rotation speed of the wheel can be converted from the rotation speed of the motor. On the other hand, vehicle speed and acceleration cannot be converted to vehicle speed when the drive wheels are slipping. Observation can be performed by attaching a rotation sensor to a non-slip driven wheel, but the cost increases due to the addition of the rotation sensor. In addition, since the four-wheel drive does not have a driven wheel, it is necessary to detect the speed by adding a driven wheel, which is not practical and generally difficult to detect the speed and acceleration.

If the acceleration is known using an accelerometer, the speed can be calculated, but in the case of a vehicle, gravitational acceleration is applied to the accelerometer when it is tilted on a slope. Since gravity and acceleration cannot be separated in principle, accurate acceleration cannot be detected.
Therefore, if the inclination of the vehicle encountered on the inclined road can be detected, the inclination of the road can be known, and the actual acceleration and speed obtained by subtracting the influence of the gravitational acceleration can be calculated from the inclination of the road. However, if an inclinometer is used to detect the inclination of the vehicle, the inclination of the vehicle cannot be accurately detected because the inclinometer is influenced by acceleration. In this case, the slip of the drive wheel cannot be detected accurately.

  An object of the present invention is to provide a slip control device for an electric vehicle that can detect a vehicle tilt and accurately detect a slip of a drive wheel.

An electric vehicle slip control device 20 according to the present invention is an electric vehicle slip control device that performs slip control of an electric vehicle that is a vehicle including an electric motor 3 that rotationally drives the drive wheels 7.
Vehicle speed detection means 18 for detecting the speed of the vehicle;
Drive wheel rotation speed calculation means 19 for calculating the rotation speed of the drive wheel 7 from the detection value of the rotation angle sensor 3a for detecting the rotation speed of the motor 3;
When the rotational speed of the driving wheel 7 calculated by the driving wheel rotational speed calculating means 19 is compared with the vehicle speed detected by the vehicle speed detecting means 18, the rotational speed of the driving wheel 7 is higher than the vehicle speed. Slip determining means 21 for determining that the drive wheel 7 has slipped,
In this slip judgment means 21,
Vehicle inclination angle detecting means 25 for detecting the inclination angle of the front and rear of the vehicle from the two atmospheric pressure sensors 28F and 28R respectively attached to the front and rear of the vehicle;
A vehicle speed correction that corrects the vehicle speed using an inclination angle / correction amount setting means 33 that sets the relationship between the inclination angle and the vehicle speed correction amount from the front and rear inclination angles of the vehicle detected by the vehicle inclination angle detection means 25. Means 24 is provided.

  According to this structure, the vehicle speed detection means 18 detects a vehicle speed by integrating the acceleration detected using the accelerometer etc. with time, for example. The vehicle speed is detected at all times or every predetermined time. This vehicle speed is corrected by the vehicle speed correction means 24 as follows. The vehicle inclination angle detection means 25 detects the inclination angle of the front and rear of the vehicle from the two atmospheric pressure sensors 28F and 28R at the front and rear of the vehicle. The vehicle inclination angle detection means 25 detects, for example, an altitude difference h before and after the vehicle based on an atmospheric pressure difference between the two atmospheric pressure sensors 28F and 28R, and detects an inclination angle θ before and after the vehicle based on the altitude difference h.

If the atmospheric pressure difference between the two atmospheric pressure sensors 28F and 28R is ΔP (Pa), the distance between the two atmospheric pressure sensors 28F and 28R is D (m), and the altitude difference between the two atmospheric pressure sensors 28F and 28R is h (m), The front-rear inclination angle θ (°) of the vehicle is expressed as follows near the sea surface, for example.
θ = arcsin (h / D)
However, h = ΔP / 11.9
It can be calculated with a pressure difference of 11.9 Pa per meter near the sea surface, but when the altitude where the vehicle exists is not near the sea surface, the calculation accuracy can be obtained by using a coefficient that matches the altitude where the vehicle exists. Will improve.

The vehicle speed correction means 24 corrects the vehicle speed from the front / rear inclination angle θ of the vehicle using the inclination angle / correction amount setting means 33. In the tilt angle / correction amount setting means 33, the relationship between the front and rear tilt angles of the vehicle and the vehicle speed correction amount is set. This relationship is determined by the results of experiments, simulations, and the like, for example. The slip determination means 21 compares the rotation speed of the drive wheel 7 calculated by the drive wheel rotation speed calculation means 19 with the corrected vehicle speed. The slip determination means 21 determines that the drive wheel 7 has slipped when the rotational speed of the drive wheel 7 is greater than the vehicle speed.
By using the relative atmospheric pressure difference between the two atmospheric pressure sensors 28F and 28R, it is possible to accurately detect the inclination angle θ before and after the vehicle without being affected by the acceleration. Or you can know exactly when you are downhill. The slip determining means 21 accurately detects the slip of the drive wheel 7 from the vehicle speed and the drive wheel rotation speed obtained by detecting the inclination of the vehicle and subtracting the influence of the gravitational acceleration from the acceleration applied to the vehicle. Can do. For example, when it is determined that the drive wheel 7 has slipped, the slip control device 20 can perform control to take necessary measures.

  The vehicle inclination angle detection means 25 may include a sensor calibration unit 29 that calibrates the relative pressures of the atmospheric pressure sensors 28F and 28R from the outputs of the two atmospheric pressure sensors 28F and 28R on a flat ground. The atmospheric pressure sensors 28F and 28R are generally superior in the accuracy and resolution of the relative pressure, but the accuracy of the absolute pressure is inferior to the accuracy of the relative pressure. When calculating the pressure difference using the two atmospheric pressure sensors 28F and 28R, the accuracy of the absolute pressure becomes a problem. Therefore, for example, when the vehicle is manufactured, the sensor calibration unit 29 records the sensor outputs of the two atmospheric pressure sensors 28F and 28R on a flat ground, and calibrates the values so that the angle becomes “zero”. Whether it is the “flat ground” is determined using, for example, an inclinometer. Thus, by calibrating the sensor outputs of the two atmospheric pressure sensors 28F and 28R, it is possible to accurately detect the front-rear inclination angle θ of the vehicle.

  When the slip determination means 21 determines that the drive wheel 7 has slipped, a slip torque control means 22 for limiting the torque generated by the motor 3 may be provided. In this case, the slip torque control means 22 limits the torque of the motor 3 of the drive wheel 7 where the slip has occurred, so that the occurrence of slip is reliably prevented thereafter.

  The motor 3 may be a motor constituting the in-wheel motor drive device 11. In the case of the in-wheel motor drive device 11, each drive wheel 7 is individually motor-driven, and the influence of slip is large, and the effect by the slip control according to the present invention is more effectively exhibited.

  An electric vehicle slip control device according to the present invention is an electric vehicle slip control device that performs slip control of an electric vehicle, which is a vehicle equipped with an electric motor that rotationally drives drive wheels. The vehicle speed detection that detects the speed of the vehicle. Means, a driving wheel rotational speed calculating means for calculating a rotational speed of the driving wheel from a detection value of a rotational angle sensor for detecting a rotational speed of the motor, and a driving wheel rotational speed calculating means for calculating the rotational speed of the driving wheel. A slip judging means for comparing the rotational speed with the vehicle speed detected by the vehicle speed detecting means, and judging that the drive wheel slips when the rotational speed of the drive wheel is higher than the vehicle speed; The judging means includes a vehicle inclination angle detecting means for detecting an inclination angle of the front and rear of the vehicle from two atmospheric pressure sensors attached to the front and rear of the vehicle, and the vehicle inclination. Vehicle speed correction means for correcting the vehicle speed using an inclination angle / correction amount setting means in which a relationship between the inclination angle and the vehicle speed correction amount is set based on the vehicle front and rear inclination angles detected by the angle detection means is provided. . For this reason, it is possible to accurately detect the slip of the driving wheel by detecting the inclination of the vehicle.

1 is a block diagram of a conceptual configuration of an electric vehicle drive device provided with an electric vehicle slip control device according to an embodiment of the present invention. FIG. It is a block diagram which shows the specific example of the same electric vehicle drive device. It is sectional drawing of the in-wheel motor drive device of the same electric vehicle. It is a block diagram which shows the conceptual structure of the slip control apparatus in the same electric vehicle drive device. It is a figure which shows roughly the vehicle inclination angle detection means of the slip control apparatus. It is a block diagram which shows the relationship between the atmospheric | air pressure sensor of the same slip control apparatus, VCU, an inverter apparatus, etc.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a conceptual configuration of an electric vehicle drive device including a slip control device according to this embodiment. The electric vehicle drive device includes a VCU (vehicle control unit) 1 and an inverter device 2. The VCU 1 is a computer-type vehicle control unit that performs integrated control and cooperative control of the entire vehicle, and is also referred to as an ECU (electric control unit).

  The inverter device 2 is a device that applies a driving current to each motor 3 for driving driving in accordance with a driving command sent from the VCU 1. The VCU 1 and the inverter device 2 are connected so as to be able to transmit signals to each other by CAN (controller area network) communication or the like. The figure shows an example in which the left and right wheels are applied to a vehicle driven by a motor 3 respectively. In this example, the motor 3 is a synchronous motor or an induction motor driven by a three-phase alternating current. A drive command indicating the accelerator operation amount output from the accelerator operation sensor 4a is input to the VCU 1 and is distributed from the VCU 1 to the inverter devices 2 and 2 for the motors 3 and 3.

  FIG. 2 is a block diagram showing a specific example of the electric vehicle driving apparatus. This electric vehicle is a four-wheeled vehicle provided with driven wheels 6 and 6 as front wheels and driving wheels 7 and 7 as rear wheels on the vehicle body of the vehicle 5. The left and right front wheels may be drive wheels, and the left and right rear wheels may be driven wheels. The motor 3 constitutes an in-wheel motor drive device 11 together with the wheel bearing 9 and the speed reducer 10. The speed reducer 10 decelerates the rotational output of the motor 3 and transmits it to a rotating side race (not shown) of the wheel bearing 9.

  FIG. 3 is a cross-sectional view of the in-wheel motor drive device 11. Each in-wheel motor drive device 11 includes a motor 3, a speed reducer 10, and a wheel bearing 9, and a part or all of these are disposed in the wheel. The rotation of the motor 3 is transmitted to the drive wheel 7 via the speed reducer 10 and the wheel bearing 9. A brake rotor BR is fixed to the flange portion of the hub wheel 9 a of the wheel bearing 9, and the brake rotor BR rotates integrally with the drive wheel (wheel) 7. The motor 3 is, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in the core portion of the rotor 3a. This motor 3 is a motor in which a radial gap is provided between a stator 3b fixed to the housing Hs and a rotor 3a attached to the rotation output shaft 3c.

  As shown in FIG. 2, the accelerator operation amount 4, the brake operation amount 12, and the steering operation amount signal from the accelerator operation sensor 4 a of the accelerator 4, the brake operation sensor 12 a of the brake 12, and the steering sensor 13 a of the handle 13 are transmitted to the VCU 1. Is entered. The VCU 1 generates a torque command value to be distributed to the left and right motors 3 and 3 in accordance with the accelerator operation amount signal of the accelerator operation sensor 4a in consideration of the brake operation amount and handle operation amount signals. 2 and 2 are given. Each inverter device 2, 2 converts the DC power of the battery 8 into a motor drive current of AC power, and controls the motor drive current according to the torque command.

  The inverter devices 2 and 2 are provided with the electric vehicle slip control devices 20 and 20 according to this embodiment. The slip control device 20 is a device that performs slip control of an electric vehicle that is a vehicle provided with the electric motor 3 for traveling driving. The slip control device 20 may be provided in the VCU 1. In addition, atmospheric pressure sensors 28F and 28R are respectively attached to the vehicle bodies before and after the vehicle 5, and detect the front and rear inclination angles of the vehicle as will be described later.

  FIG. 4 is a functional block diagram showing the configuration of the inverter device 2, particularly the configuration of the slip control device 20. The inverter device 2 includes an inverter 17 that converts DC power into three-phase AC power, and torque control means 16 that converts a torque command given from the VCU 1 into a current command and controls the current output of the inverter 17. The torque control means 16 has control means such as vector control for improving efficiency in accordance with the rotation angle of a rotor (not shown) of the motor 3. For the control, the torque control means 16 includes a rotation angle sensor 3 a provided in the motor 3. The detection value of the rotation angle is input. The torque control means 16 is provided in a weak electric circuit portion composed of a microcomputer or other electronic circuit, and a slip control device 20 is provided in this weak electric circuit portion.

  The slip control device 20 includes vehicle speed detection means 18, drive wheel rotation speed calculation means 19, slip determination means 21, slip torque control means 22, and torque recovery means 23. The vehicle speed detecting means 18 detects the vehicle speed by, for example, integrating the acceleration detected using an accelerometer or the like with time. The vehicle speed is detected at all times or every predetermined time. This vehicle speed is corrected by the vehicle speed correcting means 24 as will be described later.

  The drive wheel rotation speed calculation means 19 measures the rotation speed of the motor 3 with the rotation angle sensor 3a, and calculates the rotation speed of the drive wheel 7 from the detected value of the rotation angle sensor 3a. The slip determination means 21 is a means for determining that the drive wheel 7 driven by the motor 3 has slipped. The vehicle inclination angle detection means 25, the vehicle speed correction means 24, the comparison section 26, and the slip determination section 27 Have The vehicle inclination angle detection means 25 detects the inclination angle of the front and rear of the vehicle from the two atmospheric pressure sensors 28F and 28R attached to the front and rear of the vehicle, respectively.

  FIG. 5 is a diagram schematically showing vehicle inclination angle detection means of the slip control device. Hereinafter, description will be made with reference to FIG. 4 as appropriate. The vehicle inclination angle detection means 25 detects an altitude difference h before and after the vehicle 5 based on an atmospheric pressure difference between the two atmospheric pressure sensors 28F and 28R, and detects an inclination angle θ before and after the vehicle 5 from the altitude difference h. The position “front and rear of the vehicle” represents a position where the two atmospheric pressure sensors 28F and 28R installed before and after the vehicle 5 are installed. The installation locations of the two atmospheric pressure sensors 28F and 28R are provided at the same height in the vehicle 5. Therefore, the altitude difference h before and after the vehicle 5 is the same as the altitude difference between the two atmospheric pressure sensors 28F and 28R. When the installation positions of the two atmospheric pressure sensors 28F and 28R are not provided at the same height in the vehicle 5, the altitude difference h before and after the vehicle 5 is calculated based on the altitude difference obtained from the atmospheric pressure difference. What is necessary is just to obtain | require by subtracting the difference of the installation position height of the sensors 28F and 28R.

If the atmospheric pressure difference between the two atmospheric pressure sensors 28F and 28R is ΔP (Pa), the distance between the two atmospheric pressure sensors 28F and 28R is D (m), and the altitude difference between the two atmospheric pressure sensors 28F and 28R is h (m), The front-rear inclination angle θ (°) of the vehicle 5 is expressed as follows near the sea surface, for example.
θ = arcsin (h / D)
However, h = ΔP / 11.9
In addition, it can be calculated with a pressure difference of 11.9 Pa per meter near the sea surface, but when the altitude where the vehicle 5 exists is not near the sea surface, by using a coefficient that matches the altitude where the vehicle 5 exists, Calculation accuracy is improved. For example, since the atmospheric pressure near the sea surface changes to 0.89 at an altitude of 1,000 m with respect to 1 atm, the coefficient is 0.89 when the vehicle 5 exists at an altitude of 1,000 m. The altitude difference h may be obtained by multiplying 9Pa by a coefficient 0.89.
Specifically, the vehicle inclination angle detection means 25 calculates the current altitude of the vehicle 5 from, for example, the average value of the atmospheric pressure detected by the two atmospheric pressure sensors 28F and 28R, and sets the relationship between the altitude and the coefficient. The coefficient corresponding to the calculated altitude is selected from the table. The current altitude of the vehicle 5 may be calculated from the atmospheric pressure detected by any one of the atmospheric pressure sensors 28F and 28R instead of the average value of the atmospheric pressure.

  The vehicle inclination angle detection means 25 includes a sensor calibration unit 29 that calibrates the relative pressures of the atmospheric pressure sensors 28F and 28R from the outputs of the two atmospheric pressure sensors 28F and 28R on a flat ground. The atmospheric pressure sensors 28F and 28R are generally superior in the accuracy and resolution of the relative pressure, but the accuracy of the absolute pressure is inferior to the accuracy of the relative pressure. When calculating the pressure difference using the two atmospheric pressure sensors 28F and 28R, the accuracy of the absolute pressure becomes a problem.

  Therefore, for example, when the vehicle 5 is manufactured, the sensor calibration unit 29 records the sensor outputs of the two atmospheric pressure sensors 28F and 28R on a flat ground, and calibrates the values so that the angle becomes “zero”. Whether it is the “flat ground” is determined using, for example, an inclinometer. Thus, by calibrating the sensor outputs of the two atmospheric pressure sensors 28F and 28R, the front-rear inclination angle θ of the vehicle 5 can be accurately detected. It is possible to calibrate the sensor outputs of the two atmospheric pressure sensors 28F and 28R automatically or manually when the vehicle 5 starts.

FIG. 6 is a block diagram showing the relationship among the atmospheric pressure sensors 28F and 28R, the VCU 1, the inverter device 2, and the like.
The two atmospheric pressure sensors 28F and 28R are electrically connected to the VCU 1 via communication means such as CAN bus communication. Each atmospheric pressure sensor 28F, 28R has an atmospheric pressure sensor IC 31 and a communication IC 32 mounted on the substrate 30, respectively. The atmospheric pressure sensor IC31 is made of, for example, a piezo element, senses atmospheric pressure, outputs an electric signal corresponding to the pressure as a sensor output, and inputs this sensor output to the VCU1 via the communication means using the communication IC32. . The sensor output is input from the VCU 1 to the vehicle inclination angle detection unit 25 via the communication unit. As shown in FIG. 4, the sensor outputs output from the atmospheric pressure sensors 28 </ b> F and 28 </ b> R may be input to the vehicle inclination angle detection unit 25 without the VCU 1 (see the dotted line in FIG. 4).

  The vehicle speed correction means 24 corrects the vehicle speed using the inclination angle / correction amount setting means 33 from the front and rear inclination angles of the vehicle 5 detected by the vehicle inclination angle detection means 25. In the tilt angle / correction amount setting means 33, the relationship between the front and rear tilt angles of the vehicle 5 and the vehicle speed correction amount is set. This relationship is determined by the results of experiments, simulations, and the like, for example.

  The comparison unit 26 compares the rotational speed of the drive wheel 7 calculated by the drive wheel rotational speed calculation means 19 with the corrected vehicle speed. The slip determination unit 27 determines that the drive wheel 7 is slipping if the rotational speed of the drive wheel 7 is greater than the corrected vehicle speed. The slip determination unit 27 may count the number of consecutive times when the rotational speed of the drive wheel 7 exceeds the corrected vehicle speed, and may determine that the slip has occurred when the count value reaches the set number of times. In this case, for example, even if the variation in the rotational speed of the drive wheels 7 becomes large, it can be determined more precisely whether or not the drive wheels 7 have slipped. The set number of times is set, for example, based on results of experiments, simulations, and the like.

  When the slip determining unit 27 determines that the driving wheel 7 has slipped, the slip torque control means 22 limits the torque command value to the motor 3 that drives the driving wheel 7. The limitation on the torque command value includes setting the command value to “zero”. The command value of the torque to be limited is determined by the results of experiments and simulations, for example. Thus, the slip torque control means 22 can eliminate the slip of the drive wheel 7 by limiting the command value of the torque to the motor 3.

  The torque recovery means 23 limits the torque command value to the motor 3 by the slip torque control means 22 and then gradually recovers the torque generated by the motor 3 in accordance with a predetermined standard. The maximum value is the accelerator torque command. For example, if the torque of the motor 3 of the drive wheel 7 where the slip occurs is reduced to zero and then suddenly recovered, the vehicle 5 suddenly accelerates, and the occupant of the vehicle 5 feels uncomfortable. With a configuration that gradually recovers the vehicle, it is possible to maintain comfortable driving performance that does not cause the passenger to feel uncomfortable.

  According to the slip control device described above, the front and rear tilt angles of the vehicle 5 can be accurately detected without being affected by the acceleration, using the relative pressure difference between the two pressure sensors 28F and 28R. Therefore, it can be accurately grasped at any time whether the vehicle 5 is on a flat ground, uphill, or downhill. The slip determination means 21 can accurately detect the slip of the drive wheel 7 from the vehicle speed obtained by detecting the inclination of the vehicle 5 and subtracting the influence of the gravitational acceleration and the rotation speed of the drive wheel. Based on this accurate detection result, the slip torque control means 22 can take measures to limit the command value of the torque to the motor 3.

  The motor 3 is a motor constituting the in-wheel motor drive device 11. For this reason, each drive wheel 7 is individually motor-driven, and the influence of slip is large, and the effect of this slip control is more effectively exhibited.

The in-wheel motor drive device 11 is a so-called direct motor type in which a cycloid speed reducer, a planetary speed reducer, a two-axis parallel speed reducer, and other speed reducers can be applied. Also good.
The vehicle 5 may be a four-wheel drive vehicle. In a four-wheel drive vehicle or a two-wheel drive vehicle, the left and right wheels may be so-called on-board drive wheels that are driven by one or two motors installed on the vehicle body.

DESCRIPTION OF SYMBOLS 3 ... Motor 3a ... Rotation angle sensor 7 ... Drive wheel 11 ... In-wheel motor drive device 18 ... Vehicle speed detection means 19 ... Drive wheel rotational speed calculation means 20 ... Slip control device 21 ... Slip judgment means 22 ... Torque control means 24 at the time of slip ... Vehicle speed correction means 25 ... Vehicle inclination angle detection means 28F, 28R ... Pressure sensor 29 ... Sensor calibration unit 33 ... Inclination angle / correction amount setting means

Claims (4)

In a slip control device for an electric vehicle that performs slip control of an electric vehicle that is a vehicle equipped with an electric motor that rotates and drives a drive wheel,
Vehicle speed detection means for detecting the speed of the vehicle;
Drive wheel rotation speed calculation means for calculating the rotation speed of the drive wheel from a detection value of a rotation angle sensor for detecting the rotation speed of the motor;
When the rotational speed of the driving wheel calculated by the driving wheel rotational speed calculating means is compared with the vehicle speed detected by the vehicle speed detecting means, and the rotational speed of the driving wheel is greater than the vehicle speed, the driving wheel Slip judging means for judging that the vehicle has slipped,
In this slip judgment means,
Vehicle inclination angle detection means for detecting an inclination angle of the front and rear of the vehicle from two atmospheric pressure sensors respectively attached to the front and rear of the vehicle;
Vehicle speed correction means for correcting the vehicle speed using an inclination angle / correction amount setting means in which a relationship between the inclination angle and the vehicle speed correction amount is set from the front and rear inclination angles of the vehicle detected by the vehicle inclination angle detection means; An electric vehicle slip control device characterized by comprising:   2. The electric vehicle slip control device according to claim 1, wherein the vehicle inclination angle detecting means includes a sensor calibration unit that calibrates relative pressures of the two atmospheric pressure sensors from outputs of the two atmospheric pressure sensors on a flat ground. Slip control device.   3. A slip control device for an electric vehicle according to claim 1, further comprising a slip torque control means for limiting a torque generated by the motor when the slip determination means determines that the drive wheel has slipped. Electric vehicle slip control device.   The electric vehicle slip control device according to any one of claims 1 to 3, wherein the motor is a motor constituting an in-wheel motor drive device.

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