JP2010259294A - Vehicle controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in control stability even if a longitudinal vibration (pitching), a vertical jumping (bouncing) or a shake of a vehicle body in a turning direction arises when an electric vehicle in which wheels are driven by independent electric motors respectively travels on a straight line. <P>SOLUTION: The vehicle controller 100 of a four-wheel electric vehicle 10 includes: a pitching detecting section 130 for detecting a vertical vibration around right/left axis around the barycenter of the electric vehicle; a yaw rate sensor 150 for detecting the speed at which a rotation angle of the turning direction changes; a pitching moment computing section 140 for calculating the pitching moment; and a yaw moment computing section 160 for calculating a yaw moment from a yaw rate. A torque computing section 170 optimizes the output torque of each of in-wheel motors so that the pitching moment and the yaw moment both become zero. <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 equipped with an internal combustion engine such as an engine have pitching or vertical jumping (pitching) or vertical jumping ( Bouncing) and disturbances such as swinging of the vehicle body.

  When the above-described disturbance is applied to the electric vehicle during straight traveling, the load applied to the wheel changes for each wheel. Therefore, the slip rate changes for each tire mounted on the wheel. Therefore, there has been a problem that the steering stability of the vehicle when going straight is lowered.

  On the other hand, for example, a control system that stabilizes the behavior of 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. 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, so the difference in road surface unevenness and road resistance is driven by each wheel. The effect on torque is large.

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

  Therefore, the present invention provides an electric vehicle in which each wheel is driven by an independent electric motor, and when the electric vehicle travels straight, disturbances such as pitching, bouncing and bouncing in the turning direction are given. Therefore, an object of the present invention is to provide a vehicle control device for an electric vehicle that can prevent a decrease in steering stability.

  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 for an electric vehicle in which each wheel is driven by an independent electric motor, the torque detection unit detecting an output torque of the electric motor, and the wheel mounted on each wheel. A pitching detection unit that detects vertical vibration around the left-right axis centered on the center of gravity of the electric vehicle based on a load applied to the ground contact surface of the tire by each tire, and calculates a pitching moment from the detected vertical vibration A pitching moment calculator; a yaw rate detector that detects a speed at which the rotation angle of the electric vehicle changes in the turning direction; and a yaw moment calculator that calculates a yaw moment generated in the electric vehicle from the detected yaw rate. The electric mode so that the calculated pitching moment value and yaw moment value are both zero. And summarized in that and a drive control section for controlling the output command value for driving the motor.

  According to the first feature of the present invention, the drive control unit adjusts the pitching moment calculated from the vertical vibration (pitching) of the electric vehicle and the speed (yaw rate) at which the rotation angle of the turning direction of the electric vehicle changes. Based on this, the electric motor is driven so that these values become zero. That is, the drive control unit can set an appropriate output command value in consideration of the pitching of the electric vehicle and the vehicle body swing in the turning direction. As a result, it is possible to prevent the traveling of the vehicle from becoming unstable due to fluctuations in the load applied to each wheel due to pitching or swinging of the vehicle body in the turning direction.

  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, when the vehicle is traveling straight, the electric vehicle is pitched, bounced up and down, and in the turning direction. Even if a disturbance such as a body shake is given, it is possible to prevent a decrease in steering stability.

  According to the features of the present invention, during straight running of an electric vehicle in which each wheel is driven by an independent electric motor, roll (roll), pitch (pitching), vertical jump (bouncing), body swing in the turning direction ( Even if a disturbance such as yaw) 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) the overall schematic configuration of the electric automobile, (2) the configuration of the vehicle control device for the electric automobile, (3) the motor torque control method, (4) the action / 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 straight traveling determination / acceleration calculation unit 120, a pitching detection unit 130, a pitching moment calculation unit 140, a yaw rate sensor 150, a yaw moment calculation unit 160, and a torque calculation. Unit 170 and motor control unit 180.

  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 straight traveling determination / acceleration calculation unit 120 determines that the electric four-wheeled vehicle 10 is traveling straight based on signals from a vehicle speed sensor, a steering angle sensor, and other acceleration sensors (not shown).

  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 yaw rate sensor 150 detects the yaw rate that acts on the electric automobile 10. That is, the speed at which the rotation angle in the turning direction of the electric automobile 4 changes is detected. The yaw moment calculator 160 calculates a yaw moment that acts on the electric four-wheeled vehicle 10 from the detected yaw rate.

  The torque calculator 170 is configured to detect the motor torque based on the output command value acquired by the output command value acquisition unit 110 and the pitching moment calculator 140 when the straight traveling determination / acceleration calculator 120 detects that the vehicle is in the straight traveling state. From the calculated pitching moment and the yaw moment calculated by the yaw moment calculation unit 160, the output torque of the in-wheel motors 30FL, 30FR, 30RL, 30RR is calculated. Specifically, the torque calculation unit 170 is configured to adjust the in-wheel motors 30FL, 30FR, 30RL, and 30RR so that the pitching moment value and the yaw moment value are both zero when the electric automobile 10 is traveling straight. Calculate the output torque.

  Based on the torque calculated by the torque calculation unit 170, the motor control unit 180 generates the predetermined motor torque in the in-wheel motors 30FL, 30FR, 30RL, 30RR, and the in-wheel motors 30FL, 30FR, 30RL, 30RR. 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 straight travel determination / acceleration calculation unit 120 determines that the electric four-wheeled vehicle 10 is traveling straight. When traveling straight, in step S2, the pitching detection unit 130 detects vibration due to disturbance such as pitching (pitching) and vertical jumping (bouncing). The yaw rate sensor 150 detects the speed at which the rotation angle of the electric automobile 10 in the turning direction changes.

  In step S <b> 3, the pitching moment calculation unit 140 calculates a pitching moment that acts on the electric automobile 10 from the signal detected by the pitching detection unit 130. The yaw moment calculator 160 calculates a yaw moment that acts on the electric four-wheeled vehicle 10 from the detected yaw rate.

  In step S4, the torque calculation unit 170 calculates the output torque of the in-wheel motors 30FL, 30FR, 30RL, and 30RR so that the pitching moment value and the yaw moment value calculated by the pitching moment calculation unit 140 are both zero. To do.

  In step S5, the motor control unit 180 generates the predetermined motor torque in the in-wheel motors 30FL, 30FR, 30RL, 30RR based on the torque calculated in the torque calculation unit 170, and the in-wheel motors 30FL, 30FR. , 30RL, 30RR to control the output command value.

(4) Action / Effect The vehicle control apparatus 100 determines the vertical vibration (pitching and bouncing) of the electric automobile 10 and the speed (yaw rate) at which the rotation angle of the electric automobile 10 changes in the turning direction. The in-wheel motors 30FL, 30FR, 30RL, and 30RR are driven so that the pitching moment and the yaw moment calculated from the vertical swing are zero. That is, the vehicle control device 100 can set an appropriate output command value in consideration of the pitching of the electric automobile 10 and the vehicle body shake in the turning direction. As a result, it is possible to prevent the traveling of the vehicle from becoming unstable due to fluctuations in the load applied to each wheel due to pitching or swinging of the vehicle body in the turning direction.

  Therefore, according to the vehicle control apparatus 100 for the electric automobile 10, the electric automobile 4 is pitched (pitched) when the electric automobile 10 that drives each wheel by an independent electric motor travels straight ahead. ), Even if disturbances such as bouncing up and down (bouncing) and body swing in the turning direction are 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.

  In the present embodiment, as an example, a four-wheeled electric four-wheeled automobile has been described as an example, but the present invention can also be applied to an automobile having wheels other than four wheels such as six wheels.

  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 device, 110 ... Output command value acquisition part, 120 ... Straight-running determination and acceleration Calculation unit, 130 ... Pitching detection unit, 140 ... Pitching moment calculation unit, 150 ... Yaw rate sensor, 160 ... Yaw moment calculation unit, 170 ... Torque calculation unit, 180 ... Motor control unit

Claims (1)

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 yaw rate detector that detects the speed at which the rotation angle of the turning direction of the electric vehicle changes;
A yaw moment calculator for calculating a yaw moment generated in the electric vehicle from the detected yaw rate;
A vehicle control device for an electric vehicle, comprising: a drive control unit that controls an output command value for driving the electric motor so that the calculated pitching moment value and yaw moment value are both zero.

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