JP6554808B2 - Vehicle that suppresses brake vibration by regenerative generator - Google Patents

Description

  The present invention relates to a vehicle equipped with a friction brake such as a disc brake, which suppresses the occurrence of “judder” in which a vibration component is generated in the braking torque when the brake is operated and the brake vibrates.

  In friction brakes such as disc brakes that press the pads against the disc rotor and brake the rotation of the wheels, vibration components are generated in the braking torque when the brakes are activated due to thermal deformation of the rotor, and the brakes vibrate. And is called "Judder". Regarding the suppression of such judder, when the brake is an electric disc brake that presses the pad against the disc by the electric motor, the operating current of the pad operating motor can be changed by feedback control based on the vibration component generated in the braking torque. Is described in Patent Document 1 below.

JP 2013-133002 A

  The vibration component of the braking torque generated in the brake rotor when the pad is pressed is a high-frequency vibration component that cannot be followed by the response speed of the hydraulic circuit when the friction brake is hydraulic. Further, since the frequency of the vibration component increases as the number of rotations of the brake rotor increases, even when the friction brake is an electric type, the electric pad operation response speed is limited when the vehicle is braked at high speed. It is considered that the braking vibration generated in the friction brake cannot be suppressed by the feedback control of the operation.

  On the other hand, there is a regenerative brake as means for effectively recovering the kinetic energy as electric power by a generator during braking of the vehicle. In particular, there are many vehicles equipped with wheels driven by an electric motor, such as an electric vehicle and a hybrid vehicle, and the electric motor can operate as a regenerative generator as it is. The motor can be operated as a regenerative brake generator as it is. In any case, if the wheel braked by the friction brake is also braked by the regenerative brake, the vibration component generated in the braking torque at the time of braking by the friction brake counteracts the vibration component to the regenerative brake. It is conceivable to suppress it directly by generating. An object of the present invention is to suppress, by a regenerative generator, braking vibration generated when a friction brake is operated in a vehicle including a friction brake and a regenerative brake.

  In order to solve the above problems, the present invention detects a vibration component of deceleration generated when the friction brake is operated in a vehicle having wheels braked by a friction brake and a regenerative brake, and detects the vibration component. The present invention proposes a vehicle having vibration suppression control means for generating a vibration suppression torque to be suppressed in the regenerative brake.

  In the above vehicle, when the regenerative brake generates a damping torque that suppresses a vibration component of deceleration generated when the friction brake is operated, a regenerative output region reduced by a predetermined amount from an upper limit value of the regenerative output. It may be operated by.

  In the above vehicle, the vibration suppression control means may generate the vibration suppression torque in the regenerative brake by feedforward control based on detection of a vibration component of deceleration generated when the friction brake is operated.

  As described above, in a vehicle having a wheel braked by a friction brake and a regenerative brake, the vibration component of the deceleration generated when the friction brake is operated is detected, and the damping torque for suppressing the vibration component is generated by the regenerative torque. If vibration suppression control means for generating the brake is provided, even if a vibration component is generated in the deceleration when the friction brake is operated due to thermal deformation of the brake rotor, the vibration component is suppressed. By generating the vibration torque in the regenerative brake, it can be directly pressed down to suppress the occurrence of judder.

  Since the regenerative brake effectively recovers the kinetic energy of the vehicle, it is desirable to operate at the upper limit as much as possible, but in order to vibrate the regenerative torque in order to suppress the vibration component generated in the deceleration by the friction brake In this case, the regenerative brake must be operated in an operating region lower than the upper limit value of the regenerative output. On the other hand, the vibration component is generated in the deceleration caused by the friction brake when the friction braking force increases beyond a certain value. Therefore, when the regenerative brake generates a damping torque that suppresses the vibration component of the deceleration generated when the friction brake is operated, the regenerative brake is operated in a regenerative output region that is reduced by a predetermined amount from the upper limit value of the regenerative output. If the friction brake does not vibrate, operate the regenerative brake at its maximum value as much as possible, and only when the friction brake vibrates, use the regenerative brake at the expense of the regenerative brake effectiveness. The vibration of the friction brake can be suppressed.

  The vibration component of deceleration that occurs when the friction brake is activated due to thermal deformation of the brake rotor is a vibration component that occurs periodically in synchronization with the rotation of the brake rotor. Then, it is possible to feed-forward control the damping torque that should be generated in the regenerative brake against the vibration component of the braking torque accompanying the subsequent rotation of the brake rotor based on the detection. In addition, judder can be accurately suppressed without a time delay even in the brake operation when the vehicle is traveling at high speed.

FIG. 2 is a schematic diagram illustrating an example of a vehicle including wheels braked by a friction brake and a regenerative brake in a part related to the present invention. It is a block diagram which shows the structure of the vibration suppression control part in FIG. FIG. 3 is a block diagram showing operation modes of a vehicle state calculation unit and a damping torque calculation unit in FIG. 2. It is a flowchart which shows the point which changes distribution of the braking force between a friction brake and a regenerative brake by whether the vibration of a friction brake is suppressed by a regenerative brake. It is a graph which shows the point which suppresses the vibration of a friction brake by a regenerative brake, changing distribution of braking force between a friction brake and a regenerative brake according to a raise of the vibration level of a friction brake.

  In the vehicle partially shown in FIG. 1, 10L and 10R are wheels driven or braked by motor generators 12L and 12R and braked by friction brakes 14L and 14R, respectively. In this example, the friction brakes 14L and 14R are known arbitrary hydraulic disc brakes, and are shown in the drawing by the action of hydraulic pressure controlled by a brake hydraulic circuit 18 that operates in response to depression of the brake pedal 16. Although no pad is pressed against a disc-type brake rotor not shown in the figure, the friction brakes 14L and 14R may be electric friction brakes in which the pad is pressed against the brake rotor by electric power. .

  Reference numeral 20 denotes an electronic control unit (ECU), and some input information I relating to the vehicle speed, deceleration, wheel speed, and other vehicle operating conditions is received from various sensors not shown in the figure together with the depression information of the accelerator pedal 22. In particular, the braking / driving control unit 24 controls the driving current to the motor generators 12L and 12R so as to automatically compensate the driving operation of the driver according to the depression of the accelerator pedal 22, and the damping control unit 26, the friction brake damping control according to the present invention is performed. When a vibration component appears in the deceleration when the friction brake is operated, the regenerative output of the motor generators 12L and 12R is controlled so as to generate a damping torque to counter the vibration component. . The brake pedal depression information is also input to the electronic control unit 20, and the brake hydraulic circuit 18 is also partly controlled by the electronic control unit 20.

  As shown in FIG. 2, the vibration suppression control unit 26 includes a vehicle state calculation unit 28, and brake vibration based on driver target deceleration obtained from brake pedal depression information, vehicle speed, etc., deceleration during braking, and wheel speed. Generate information. The brake vibration information is input to the damping torque calculation unit 30, and the damping torque is calculated. Based on this, the motor generator control unit 32 controls the regenerative output of the motor generators 12L and 12R.

  As shown in FIG. 3, in the vehicle state calculation unit 28, the deceleration due to the operation of the brake is high-pass processed by a high-pass filter that operates with a filter time constant calculated based on the wheel speed. A high frequency component due to the braking vibration of the included brake is extracted. Based on this vibration component, the vibration damping torque to be generated by the motor generators 12L and 12R is calculated by the vibration damping torque calculation unit 30 with reference to the phase and speed. In this case, the braking vibration of the brake caused by the thermal deformation of the brake rotor is a periodic vibration that is repeated with the rotation of the brake rotor, and the damping torque generated by the motor generators 12L and 12R is The feedforward damping torque is set in advance corresponding to the periodic vibration.

  FIG. 4 shows that, as described above, the regenerative brake is effectively operated at the maximum value as long as no vibration occurs in the friction brake, and only when the vibration is generated in the friction brake, the regenerative brake is rejuvenated at some sacrifice. It is a flowchart which shows the point which suppresses the vibration of a friction brake with a brake. When the illustrated control is started as the vehicle starts driving, the vibration state of the brake is grasped in step (S) 10, and whether or not the vibration of the friction brake is greater than or equal to a predetermined allowable value in step 20. Is judged. If the answer is no, the control proceeds to step 30, and the braking force distribution between the friction brake and the regenerative brake is set to the regenerative braking priority distribution that operates the regenerative braking to the upper limit value. On the other hand, if the answer to step 20 is yes, the control proceeds to step 40, and the vibration suppression priority distribution in which the braking force distribution between the friction brake and the regenerative brake operates in the operation region in which the regenerative braking is reduced from the upper limit value. Set to Next, at step 50, a braking force command is issued to each brake based on the braking force distribution between any of the above friction brakes and regenerative brakes.

  As shown in FIG. 5, the regenerative brake and the friction brake are operated with the braking force distribution with the regenerative braking priority at which the current braking force is at the upper limit, and no vibration is generated in the friction brake. If the vibration exceeding the allowable value is generated in the friction brake, the braking force distribution is switched to the braking force distribution with priority to vibration suppression suppression by lowering the regenerative braking force from the upper limit value and increasing the friction braking force accordingly. Based on this, vibration suppression control for suppressing vibration of the friction brake by regenerative braking is performed from time S2.

  Although the present invention has been described in detail with reference to the embodiments, it will be apparent to those skilled in the art that various modifications can be made to the illustrated embodiments within the scope of the present invention.

  10L, 10R ... wheels, 12L, 12R ... motor generator, 14L, 14R ... friction brake, 16 ... brake pedal, 18 ... brake hydraulic circuit, 20 ... electronic control unit (ECU), 22 ... accelerator pedal, 24 ... brake drive Control part 26 ... Vibration suppression control part 28 ... Vehicle state calculation part 30 ... Damping torque calculation part 32 ... Motor generator control part

Claims (1)

In a vehicle having a wheel braked by a friction brake and a regenerative brake, a vibration component of deceleration generated when the friction brake is operated is detected, and a damping torque for suppressing the vibration component is generated in the regenerative brake. have a damping control means, said regenerative braking, when generating a suppressing damping torque vibration components deceleration occurring during operation of the friction brake, the regenerative output is decreased by a predetermined amount than the upper limit of the regeneration output vehicle characterized that you have adapted to be operated in the region.

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