JP2010259291A - Vehicle controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in control stability even if disturbance such as pitching or bouncing is given at the time of cornering of an electric vehicle in which wheels are driven by independent electric motors respectively. <P>SOLUTION: A vehicle controller 100 of an electric four-wheel vehicle 10 includes: a pitching detecting section 130 for detecting the vertical vibration around right and left axis centered at a barycenter of the electric vehicle, and a pitching moment calculating section 140 for calculating a pitching moment. A torque calculating section 160 calculates an output torque of each of in-wheel motors from an output torque of each of the in-wheel motors, a motor torque based on an output command value from an accelerator and the pitching moment. The torque calculating section 160 calculates an output torque not exceeding the maximum value of a cornering power on the basis of tire data stored in a tire data storage section 150. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle control device for an electric vehicle in which each wheel is driven by an independent electric motor.

  Conventionally, vehicles such as an electric vehicle driven by an electric motor and a four-wheeled vehicle including an internal combustion engine such as an engine have pitching or vertical jumping (pitching) or vertical jumping (depending on a road surface state such as unevenness and dry / wet) Disturbances such as bouncing are given.

  When the above-described disturbance is applied to the vehicle during cornering, the load applied to the wheel changes for each wheel. Therefore, the cornering power (CP) changes for each tire mounted on the wheel. Therefore, it has been a problem that the steering stability of the vehicle during cornering is lowered.

  On the other hand, a control system that stabilizes the vehicle by correcting the driving torque of the vehicle during cornering is disclosed (for example, Patent Document 1).

Japanese Patent No. 4161923 (pages 16-17, FIG. 7)

  However, the control system described above has the following problems. Among the vehicles described above, in an electric vehicle in which each wheel is driven by an independent electric motor, specifically, an electric automobile, the driving torque is controlled for each wheel. Therefore, during cornering, the cornering power ( The influence of the difference in CP) on the driving torque for each wheel is large.

  Therefore, in an electric vehicle in which each wheel is driven by an independent electric motor, it is difficult to appropriately correct the driving torque for each wheel, particularly in order to maintain steering stability during cornering.

  Accordingly, the present invention is an electric vehicle in which each wheel is driven by an independent electric motor. Even when cornering, the electric vehicle is subjected to steering stability even if a disturbance such as pitching or bouncing is given to the electric vehicle. An object of the present invention is to provide a vehicle control device for an electric vehicle capable of preventing the decrease of the vehicle.

  In order to solve the above-described problems, the present invention has the following features. A first feature of the present invention is a vehicle control device (vehicle control device 100) for an electric vehicle in which each wheel is driven by an independent electric motor, and a torque detection unit (motor) for detecting an output torque of the electric motor. A torque detection unit 110) and a pitching detection unit (pitching detection unit) that detects vertical vibrations about a left-right axis centered on the center of gravity of the electric vehicle based on a load applied to a tire contact surface by each tire mounted on each wheel. A detecting unit 130), a pitching moment calculating unit (pitching moment calculating unit 140) for calculating a pitching moment from the detected vertical vibration, the load applied by the tire to the contact surface, and the load applied to the contact surface Holds tire data mapped to the cornering power allowed by the tire when given to A tire data holding unit (tire data storage unit 150) and a drive control unit (torque calculation unit 160, motor control unit 170) for controlling an output command value for driving the electric motor based on the calculated pitching moment. And the drive control unit sets an output command value that does not exceed the maximum value of the cornering power based on the tire data.

  According to the first feature of the present invention, the drive control unit drives the electric motor based on the pitching moment calculated from the vertical vibration (pitching) of the electric vehicle. Further, the drive control unit sets the output command value so as not to exceed the maximum value of the cornering power based on the relationship between the load applied to the ground contact surface by the tire and the cornering power allowed for the tire.

  That is, the drive control unit can set an appropriate output command value in consideration of the pitching of the electric vehicle and the cornering performance of each tire attached to each wheel.

  Thereby, it is possible to prevent the cornering power from becoming unstable due to fluctuations in the load applied to each wheel.

  Therefore, according to the first aspect of the present invention, in an electric vehicle in which each wheel is driven by an independent electric motor, a disturbance such as pitching or bouncing is given to the electric vehicle during cornering. Even if this is done, it is possible to prevent a decrease in steering stability.

  A second feature of the present invention is summarized in that the drive control unit individually sets an output command value at which the cornering power becomes a maximum value for each electric motor based on the tire data.

  According to the features of the present invention, in an electric vehicle in which each wheel is driven by an independent electric motor, disturbance such as roll (roll), pitch (pitching), or vertical bouncing (bouncing) occurs in the electric vehicle during cornering. Even if it is given, it is possible to prevent a decrease in steering stability.

1 is a schematic perspective view of an electric automobile according to an embodiment of the present invention. It is a functional block block diagram of the drive system of the electric four-wheeled vehicle which concerns on embodiment of this invention. It is a flowchart explaining the control method of the output command value of the in-wheel motor of the electric four-wheeled vehicle which concerns on this embodiment.

  An electric vehicle according to the present invention will be described with reference to the drawings. Specifically, 1) overall schematic configuration of electric automobile, 2) configuration of vehicle control device of electric automobile, 3) motor torque control method, 4) action and effect, and 5) other Embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(1) Overall schematic configuration of an electric automobile FIG. 1 is a schematic perspective view of an electric automobile 10 according to the present embodiment. The electric automobile 10 includes electric motors, so-called in-wheel motors, inside the wheels 20FL, 20FR, 20RL, and 20RR. In other words, the electric automobile 10 drives each wheel (wheels 20FL, 20FR, 20RL, 20RR) by the independent in-wheel motors 30FL, 30FR, 30RL, 30RR.

  In addition, the electric automobile 10 includes a vehicle control device 100. The vehicle control device 100 controls the output command value according to the actual output value (output torque) of the in-wheel motors 30FL, 30FR, 30RL, 30RR.

(2) Configuration of Vehicle Control Device for Electric Four-wheeled Vehicle FIG. 2 is a configuration diagram of the electric four-wheeled vehicle 10 according to the present embodiment. The vehicle control device 100 includes an output command value acquisition unit 110, a motor torque detection unit 120, a pitching detection unit 130, a pitching moment calculation unit 140, a tire data storage unit 150, a torque calculation unit 160, and a motor control unit. 170.

  The output command value acquisition unit 110 acquires a signal based on the driver's accelerator operation, that is, an output command value for generating a predetermined motor torque in the in-wheel motors 30FL, 30FR, 30RL, and 30RR.

  The motor torque detector 120 detects the output torque of the in-wheel motors 30FL, 30FR, 30RL, 30RR of the electric automobile 10. The motor torque detector 120 calculates torque from the motor current value by calculation. A torque sensor may be used.

  The pitching detection unit 130 is a vertical vibration around the left and right axis centered on the center of gravity of the electric automobile 10 by the load applied to the ground contact surface by the tire mounted on each wheel (wheels 20FL, 20FR, 20RL, 20RR). It is an acceleration sensor that detects. The vibration in the vertical direction includes vibration due to disturbance such as pitching (pitching) and vertical jumping (bouncing).

  The pitching moment calculator 140 calculates the pitching moment from the signal representing the vertical vibration detected by the pitching detector 130.

  The tire data storage unit 150 stores tire data in which the relationship between the load applied to the ground contact surface by the tire and the cornering power allowed by the tire when the load is applied to the ground contact surface is mapped for each tire type.

  The torque calculation unit 160 includes the output torque detected by the motor torque detection unit 120, the motor torque based on the output command value acquired by the output command value acquisition unit 110, and the pitching moment calculated by the pitching moment calculation unit 140. From the above, the output torque of the in-wheel motors 30FL, 30FR, 30RL, 30RR is calculated. Based on the tire data stored in the tire data storage unit 150, the torque calculation unit 160 calculates an output torque that does not exceed the maximum value of the cornering power.

  The motor control unit 170 generates the predetermined motor torque in the in-wheel motors 30FL, 30FR, 30RL, and 30RR based on the torque calculated in the torque calculation unit 160, so that the in-wheel motors 30FL, 30FR, 30RL, and 30RR are generated. Controls the output command value given to.

(3) Motor Torque Control Method FIG. 3 is a flowchart showing a method for controlling output command values of the in-wheel motors 30FL, 30FR, 30RL, 30RR of the electric automobile 10 according to the present embodiment. The vehicle control method for an electric vehicle according to the present embodiment includes the following steps.

  As shown in FIG. 3, in step S <b> 1, the pitching detection unit 130 detects vibration due to disturbance such as pitching (pitching) and vertical jumping (bouncing).

  In step S <b> 2, the pitching moment calculation unit 140 calculates the pitching moment from the signal detected by the pitching detection unit 130.

  In step S3, the torque calculator 160 determines whether or not the pitching moment calculated by the pitching moment calculator 140 exceeds a predetermined value. If it is less than or equal to the predetermined value, the process returns to step S1. On the other hand, when it exceeds a predetermined value, it progresses to step S4.

  In step S <b> 4, the torque calculation unit 160 is calculated in the output torque detected by the motor torque detection unit 120, the motor torque based on the output command value acquired by the output command value acquisition unit 110, and the pitching moment calculation unit 140. The output torque of the in-wheel motors 30FL, 30FR, 30RL, and 30RR is calculated from the pitching moment. At this time, the torque calculation unit 160 calculates an output torque that does not exceed the maximum value of the cornering power based on the tire data stored in the tire data storage unit 150.

  In step S5, the motor control unit 170 generates the predetermined motor torque in the in-wheel motors 30FL, 30FR, 30RL, 30RR based on the torque calculated in the torque calculation unit 160, and the in-wheel motors 30FL, 30FR. , 30RL, 30RR to control the output command value.

(4) Action / Effect The vehicle control device 100 detects vertical vibrations (pitching and bouncing) of the electric four-wheeled vehicle 10, and based on the pitching moment calculated from the vertical swing, the in-wheel motor 30FL, 30FR, 30RL, 30RR are driven. At this time, the vehicle control device 100 sets the output command value so as not to exceed the maximum value of the cornering power, based on the relationship between the load applied to the ground contact surface by the tire and the cornering power allowed for the tire. That is, the vehicle control device 100 can set an appropriate output command value in consideration of the pitching of the electric automobile 4 and the cornering performance of each tire attached to each wheel. As a result, it is possible to prevent the cornering power from becoming unstable due to fluctuations in the load applied to each wheel.

  Therefore, according to the vehicle control apparatus 100, in the electric four-wheeled vehicle 10 in which each wheel is driven by the independent in-wheel motors 30FL, 30FR, 30RL, and 30RR, the electric four-wheeled vehicle 10 is pitched during cornering ( Even if a disturbance such as pitching or bouncing is given, it is possible to prevent a decrease in steering stability.

(5) Other Embodiments The content of the present invention has been disclosed according to an embodiment of the present invention. However, the present invention is not limited to the above discussion and drawings. Various embodiments that will be apparent to those skilled in the art based on the above discussion and drawings are all included in the present invention.

  In the embodiment, the description has been given for the case of the electric four-wheeled vehicle 10 including the in-wheel motors 30FL, 30FR, 30RL, and 30RR on each wheel (wheels 20FL, 20FR, 20RL, and 20RR). 20RL, 20RR) may be a vehicle equipped with an in-wheel motor. The present invention can also be applied to a vehicle that does not include an in-wheel motor.

  Further, the tire data stored in the tire data storage unit 170 may store the relationship with the cornering power allowed by the tire due to the difference in air pressure when the air pressure is different for the same tire. By providing a sensor that detects the internal pressure of the tire or the like, the steering stability of the vehicle can be further enhanced.

  For example, in the present embodiment, a four-wheeled electric automatic four-wheeled vehicle has been described as an example.

  The filler filled in the wheel may not be air. For example, nitrogen may be used. Moreover, it is not restricted to gas. It may be a liquid.

  As described above, the present invention naturally includes various embodiments that are not described herein. The technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 10 ... Electric four-wheeled vehicle, 20FL, 20FR, 20RL, 20RR ... Wheel, 30FL, 30FR, 30RL, 30RR ... In-wheel motor, 100 ... Vehicle control apparatus, 110 ... Output command value acquisition part, 120 ... Motor torque detection part , 130: Pitching detection unit, 140 ... Pitching moment calculation unit, 150 ... Tire data storage unit, 160 ... Torque calculation unit, 170 ... Motor control unit

Claims (2)

A vehicle control device for an electric vehicle in which each wheel is driven by an independent electric motor,
A torque detector for detecting an output torque of the electric motor;
A pitching detector that detects vertical vibrations about a left-right axis centered on the center of gravity of the electric vehicle by a load applied to each wheel by each tire, which is applied to the ground contact surface of the tire;
A pitching moment calculator for calculating the pitching moment from the detected vertical vibration;
A tire data holding unit for holding tire data in which a relationship between the load applied to the ground contact surface by the tire and cornering power allowed by the tire when the load is applied to the ground contact surface is mapped;
A drive control unit that controls an output command value for driving the electric motor based on the calculated pitching moment;
The drive control unit is a vehicle control device for an electric vehicle that sets an output command value that does not exceed a maximum value of the cornering power based on the tire data.   2. The vehicle control device for an electric vehicle according to claim 1, wherein the drive control unit individually sets an output command value at which the cornering power becomes a maximum value for each electric motor based on the tire data.

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