CN100404333C - Braking force control method and control device for motor vehicle - Google Patents

Abstract

Disclosed are a braking force control method and a braking force control device for a motor vehicle. It sets the degree of contribution of both the stroke amount of the brake input device and the master cylinder pressure based on at least one of the stroke amount of the brake input device and the master cylinder pressure, and will detect when a sudden brake operation by the driver of the motor vehicle (the control flag F is set to "1") when the contribution degree of the master cylinder pressure used for calculating the target braking force is set to be greater than the sudden brake operation of the driver of the motor vehicle is not detected (the control flag F is reset to "0") ”) master cylinder pressure contribution.

Description

Braking force control method and control device for motor vehicle

technical field

The present invention relates to a motor vehicle braking force control method and a motor vehicle braking force control device, in which the braking force is controlled according to the brake operation of the driver of the motor vehicle, that is, so-called brake-by-wire is performed.

Background technique

Japanese Patent Application Initial Publication No. Heisei 11-301434 published on November 2, 1999 exemplifies a previously proposed motor vehicle braking force control device. In the previously proposed braking force control device disclosed in the aforementioned Japanese Patent Application Initial Publication, a target braking force is calculated from the master cylinder pressure and the stroke of the brake pedal, and the motor vehicle braking force is controlled based on the target braking force. Here, the contribution of the master cylinder pressure and the contribution of the pedal stroke are modified according to at least one of the master cylinder pressure and the pedal stroke. In particular, at the initial stage of depressing the pedal, the contribution of the pedal stroke is made greater than the contribution of the master cylinder pressure. This is because there is a general tendency that in the low deceleration region where the desired deceleration is small, the motor vehicle driver mainly tries to adjust the pedal stroke, while in the high deceleration region where the desired deceleration is large, the motor vehicle driver mainly tries to adjust the pedal travel. Adjust pedal pressure.

Contents of the invention

In order to generate a pedal stroke and a pedal reaction force appropriate for a brake operation by a driver of a motor vehicle in the case of brake-by-wire implementation, a stroke simulator elastically contracts according to hydraulic pressure generated in a master cylinder is provided. The flow channel, which communicates primarily between the master cylinder and the stroke simulator, provides orifices for the brake fluid, which flow the brake fluid from the master cylinder into the stroke simulator. Therefore, when the driver of the motor vehicle depresses the brake pedal more abruptly desiring a large deceleration, the flow rate of the brake fluid from the master cylinder to the stroke simulator is more restricted at the initial stage of the sudden pedal depression. Therefore, the master cylinder pressure becomes greater than the master cylinder pressure when the driver of the motor vehicle gradually depresses the brake pedal. Furthermore, by limiting the flow rate of the brake fluid, the stroke of the brake pedal does not proceed as intended by the driver of the motor vehicle.

However, in the previously proposed braking force control device disclosed in the aforementioned Japanese Patent Application Initial Publication, the target braking force is calculated by setting the pedal stroke contribution to be large at the initial stage of the pedal stroke. Therefore, even if the master cylinder pressure becomes large when the driver of the motor vehicle suddenly depresses the brake pedal, the degree of contribution of the master cylinder pressure to the target deceleration increase is small. That is to say, in the initial stage of depressing the pedal, even if the driver of the motor vehicle suddenly depresses the brake pedal in the hope of a large deceleration, the pedal stroke will not increase to the extent desired by the driver of the motor vehicle. Therefore, it is difficult to say that the target braking force accurately reflects the intention of the driver of the motor vehicle.

In view of the above-mentioned problems, an object of the present invention is to provide a braking force control method and a braking force control device for a motor vehicle that can accurately reflect the driver's intention of the target of the motor vehicle even in the initial stage of the braking operation. Intention of braking force.

In order to achieve the above object, according to one aspect of the present invention, there is provided such a motor vehicle braking force control method, including: setting a brake input device, the brake input device can be manually operated by the driver of the motor vehicle; setting a master cylinder, the The master cylinder is configured to generate master cylinder pressure based on operation of a brake input device by a driver of the motor vehicle; to set the brake pressure based on at least one of stroke of the brake input device and master cylinder pressure generated in the master cylinder Inputting the stroke amount contribution degree and the master cylinder pressure contribution degree of the input device; calculating the target braking force of the motor vehicle according to the stroke amount contribution degree and the master cylinder pressure contribution degree; and controlling the braking force of the motor vehicle according to the calculated target braking force , setting the master cylinder pressure contribution for calculating the target braking force when a sudden braking operation by the motor vehicle driver is detected to be greater than the master cylinder pressure contribution when no sudden braking operation by the motor vehicle driver is detected.

In order to achieve the above object, according to another aspect of the present invention, such a motor vehicle braking force control device is provided, including: a brake input device, which can be manually operated by the driver of the motor vehicle; operation of the brake input means to generate a master cylinder pressure; a contribution setting part that sets the stroke amount of the brake input means based on at least one of the stroke amount of the brake input means and the master cylinder pressure generated in the master cylinder The contribution degree of the contribution degree and the contribution degree of the master cylinder pressure; the target braking force calculation part, which calculates the target braking force of the motor vehicle according to the contribution degree of the stroke amount of the brake input device and the contribution degree of the master cylinder pressure; and the braking force control part, It controls the braking force of the motor vehicle based on the calculated target braking force, and the contribution degree setting section sets the master cylinder pressure contribution degree used for calculating the target braking force when a sudden braking operation by the driver of the motor vehicle is detected to be greater than The master cylinder pressure contribution at the time of a sudden brake operation by the driver of the motor vehicle is not detected. Note that a sudden braking operation is defined as a braking operation in which the operating speed or operating acceleration of the braking operation of the brake input device (ie, the brake pedal) by the driver of the motor vehicle provides For a large value (for example, 0.3G or more), the preset value corresponds to the braking operation of the motor vehicle during normal driving on the street.

The summary of the present invention does not necessarily describe all features, and the present invention may also be a subcombination of the described features.

Description of drawings

FIG. 1 is a schematic configuration diagram of a braking system of a motor vehicle.

2 is a flowchart illustrating a braking force control routine executed in the first preferred embodiment of the motor vehicle braking force control apparatus according to the present invention.

FIG. 3 is a characteristic graph showing a control map for calculating the target deceleration Gs from the stroke amount Ss.

FIG. 4 is a characteristic graph showing a control map for calculating another target deceleration Gp from the master cylinder pressure Pm.

FIG. 5 is a characteristic graph showing a control map for calculating the reference master cylinder pressure Pms.

6A and 6B are characteristic graphs representing characteristics of the stroke simulator as a whole.

7A, 7B and 7C are timing charts illustrating the problems of the comparative example with respect to the first embodiment of the motor vehicle braking force control apparatus as a whole.

FIG. 8 is a block diagram showing calculation processing of the final target deceleration Gt.

9A , 9B and 9C are time charts as a whole illustrating the advantages of the first embodiment of the motor vehicle braking force control device according to the invention as compared with the time charts of FIGS. 7A to 7C .

10 is a flowchart illustrating another example of a motor vehicle braking force control routine executed in an alternative mode of the first embodiment of the motor vehicle braking force control device according to the present invention.

11 is a diagram illustrating a braking force control program executed in the second preferred embodiment of the motor vehicle braking force control device according to the present invention (when the accelerator is ON or the accelerator is OFF and the brake is OFF) flow chart.

FIG. 12 is another flowchart continuing the flowchart of FIG. 11, showing a braking force control routine (when the brake is ON) executed in the second preferred embodiment of the motor vehicle braking force control device according to the present invention. .

FIG. 13 is a characteristic graph showing a control map for calculating the contribution degree α as an alternative of the second embodiment.

Detailed ways

The following description will be made with reference to the accompanying drawings for a better understanding of the present invention.

Figure 1 shows a schematic configuration diagram of the brake system. The master cylinder 2 converts the pedal depression force applied by the driver of the motor vehicle to the brake pedal 1 (brake input device (device)) into hydraulic pressure, and has wheel hydraulic cylinders for the left and right rear wheels The primary side communicating with 3RL, 3RR and the secondary side communicating with the wheel hydraulic cylinders 3FL, 3FR of the left and right front wheels. In this case, a front-rear wheel (wheel) split system in which the brake system is divided into front wheels and rear wheels is adopted in the present braking system. Of course, the front and rear wheel diagonal split system can also be used in this braking system, which divides the braking system into left front and right rear wheel hydraulic cylinders and right front and left rear wheel hydraulic cylinders.

Install each wheel hydraulic cylinder 3FL to 3RR in disc brakes, where the braking force is generated by clamping the disc rotor under pressure with brake pads, or in drum brakes 3FL to 3RR, In this drum brake, the braking force is generated by pressing the brake shoe against the inner peripheral surface of the brake drum under pressure. The hydraulic system on the main side includes: gate valve 4r, which can close the flow path between master cylinder 2 and wheel hydraulic cylinder 3RL, 3RR; inlet valve 5RL (or 5RR), which can close gate valve 4r and wheel hydraulic cylinder 3RL (or 3RR); the outlet valve 6RL (or 6RR), which can open the flow passage between the inlet valve 5RL (or 5RR) and the wheel hydraulic cylinder 3RL (3RR) and the fluid storage tank 2a of the master cylinder 2 and a pump 7r whose suction side communicates between the outlet valve 6RL (6RR) and the reservoir 2a, and whose discharge side communicates between the gate valve 4r and the inlet valve 5RL (or 5RR).

Note that gate valve 4r, inlet valves 5RL, 5RR, and outlet valves 6RL, 6RR are each two-way-two-position switch spring-biased solenoid-operated valves. The respective gate valves 4r and the inlet valves 5RL, 5RR open the flow passages when they are in their normal positions in the de-energized state. When the outlet valve 6RL (or 5RR) is in the normal position under the non-excitation state, the flow passage is closed. It should also be noted that since each valve can open or close the flow path, each gate valve 4r and inlet valve 5RL (or 5RR) can open the flow path when they are in the biased position under excitation, while the outlet valves 6RL and 6RR are in the biased position. When in the biased position under excitation, the flow path can be closed.

Furthermore, the pump 7r is constituted by a positive displacement pump such as a gear pump, a piston pump, etc., which can ensure a substantially constant displacement regardless of the load pressure. In the above structure, when the inlet valve 5RL (or 5RR) and the outlet valve 6RL (or 6RR) are in the normal position of the de-energized state, the gate valve 4r is energized to close and the pump 7r is driven. Therefore, the pump 7r sucks the brake fluid in the reservoir tank 2a, and the discharge pressure of the pump 7r can increase the hydraulic pressure of the wheel cylinder 3RL (or 3RR).

When the outlet valve 6RL (or 6RR) is in the normal position under the non-excitation state, the gate valve 4r and the inlet valve 5RL (or 5RR) are excited to close the corresponding flow path, from the wheel hydraulic cylinder 3RL (or 3RR) to the liquid storage tank 2a Each flow passage to the pump 7r is closed so that the hydraulic pressure in the wheel cylinder 3RL (or 3RR) can be maintained. Furthermore, the outlet valve 6RL (or 6RR) is excited to open the flow path, and the gate valve 4r and the inlet valve 5RL (or 5RR) are excited to be closed, respectively. Therefore, the hydraulic pressure of wheel cylinder 3RL (or 3RR) can be released to reservoir tank 2a, thereby reducing the hydraulic pressure.

Furthermore, when the gate valve 4r, the inlet valve 5RL (or 5RR) and the outlet valve 6RL (or 6RR) are all set to the normal positions in the non-excited state, the hydraulic pressure from the master cylinder 2 is transmitted to the wheel cylinder 3RL (or 3RR), thus providing the usual braking. Note that in the hydraulic system on the secondary side, the same gate valve 4f, inlet valve 5FL (or 5FR), outlet valves 6FL, 6FR, and pump 7f are installed. Since the operation of each valve is the same as that of the main side, its detailed description is omitted here.

A stroke simulator 8 is connected to the secondary side of the master cylinder 2 . The stroke simulator 8 consists of a spring accumulator in which a compression spring 8a is inserted between the bottom of the hydraulic cylinder and the piston. As the hydraulic pressure increases, the compression spring 8a is elastically contracted (compressed), thereby generating an appropriate pedal stroke and pedal reaction force for the driver's brake operation of the motor vehicle.

The controller 9 drives and controls the gate valves 4f, 4r, the inlet valves 5FL to 5RR, the outlet valves 6FL to 6RR, and the pumps 7f, 7r. In normal times, the controller 9 executes the braking force control program shown in FIG. 2 , thereby according to the pedal stroke Ss detected by the stroke sensor 10 (stroke detection part (device)) and the pressure sensor when the gate valves 4f, 4r are closed, 11 (pressure detection part (device)) detects the master cylinder pressure Pm to execute the brake-by-wire (that is, brake force control), when the failure protection is caused by the failure of the pump 7r, etc., open the gate valve 4f, 4r, so that in the future The hydraulic pressure of master cylinder 2 is transmitted to wheel hydraulic cylinders 3FL to 3RR to provide normal braking.

Next, the braking force control routine in the first preferred embodiment executed by the controller 9 will be described based on the flowchart shown in FIG. 2 . This braking force control routine is executed as timer interrupt processing every predetermined time (for example, 10 milliseconds). As shown in FIG. 2, in a first step S1, the controller 9 reads the stroke amount Ss and the master cylinder pressure Pm. In the subsequent step S2, the controller 9 refers to the control map in FIG. 3 to calculate the target deceleration Gs from the stroke amount Ss. As shown in Figure 3, the control map is set in such a way: that is, the horizontal axis is the stroke amount Ss, and the vertical axis is the target deceleration Gs. When the stroke amount Ss increases from zero (0), the target The deceleration Gs increases from zero (0), and as the stroke amount Ss becomes larger, the increase rate of the target deceleration Gs also becomes larger.

In the subsequent step S3, the controller 9 refers to the control map shown in FIG. 4, and calculates the target deceleration Gp from the master cylinder pressure Pm. As shown in Fig. 4, this control map is set in such a way that the horizontal axis represents the master cylinder pressure Pm, and the vertical axis represents the target deceleration Gp, and when the master cylinder pressure Pm increases from 0, the target deceleration Gp is proportional to increase. In subsequent step S4, the controller 9 refers to the control map shown in FIG. 5, and calculates the reference master cylinder pressure Pms from the stroke amount Ss. As shown in FIG. 5, the control map is set in such a manner that the horizontal axis represents the stroke amount Ss, the vertical axis represents the reference master cylinder pressure Pms, and the rate of increase of the reference master cylinder pressure Pms increases as the stroke amount Ss becomes larger. Also get bigger.

In the subsequent step S5, the controller 9 judges whether the deviation (Pm-Pms) between the master cylinder pressure Pm and the reference master cylinder pressure Pms is equal to or greater than a predetermined value A1. The flow channel 12 communicating between the master cylinder 2 and the stroke simulator 8 mainly provides orifices for the brake fluid flowing from the master cylinder 2 to the stroke simulator 8 . Therefore, when the driver of the motor vehicle suddenly depresses the brake pedal 1 expecting a large deceleration, at the initial stage of the depressing of the brake pedal, due to the flow path resistance of the flow path 12, the flow from the master cylinder 2 to the stroke The flow rate of the brake fluid of the simulator 8 is limited. Accordingly, the master cylinder pressure Pm becomes larger than that in the case where the driver of the motor vehicle gradually depresses the brake pedal 1 .

Therefore, if the judgment result of step S5 indicates that (Pm-Pms)<A1, the controller 9 determines that the flow path resistance of the flow path 12 has not increased, and the driver does not suddenly step on the brake pedal (not a sudden brake operation), The procedure goes to step S6. In step S6, the control flag F is reset to "0". On the other hand, if the judgment result in step S5 is (Pm-Pms)≥A1, then the controller 9 determines that the flow path resistance of the flow path 12 increases, and judges that the driver may have performed a sudden braking operation, and the program goes to Step S7.

In step S7, the controller 9 judges the rate of change (Ss _{( n)} -Ss _(n ) of the stroke amount Ss _{(n-1)| -1)} ) is equal to or greater than the predetermined value B. If the judgment result in step S7 shows that (Ss _(n) -Ss _(n-1) )≥B, the controller 9 judges that the change speed of the stroke amount Ss is equal to or greater than a predetermined value, and judges that the driver of the motor vehicle may have performed Sudden brake operation, the procedure goes to step S8. In step S8, the controller 9 sets the control flag F to "1". On the other hand, if the judgment result in step S7 shows that (Ss _(n) -Ss _(n-1) )<B, the controller 9 judges that the change speed of the stroke amount Ss is smaller than the predetermined value B, and judges that there is a motor vehicle driving If there is no possibility of the driver performing a sudden braking operation, the routine goes to step S9.

In step S9, the controller 9 judges whether the deviation (Pm-Pms) between the master cylinder pressure Pm and the reference master cylinder pressure Pms is equal to or greater than another predetermined value A2. Note that the predetermined value A2 is larger than the previously described predetermined value A1. If the result of the judgment at step S9 indicates that (Pm-Pms)<A2, then the controller 9 judges that the driver did not perform a sudden operation on the brake pedal 1, and the procedure goes to step S6. If the judgment result of step S9 indicates that (Pm-Pms)≥A2, the controller 9 judges that the driver of the motor vehicle has performed a sudden braking operation, and the procedure goes to step S8.

In step S10 after step S8 or S6, the controller 9 refers to the map shown in the flow chart of FIG. Contribution to speed Gt. This control map is set in such a manner that the horizontal axis represents the master cylinder pressure Pm, the vertical axis represents the contribution α of the master cylinder pressure Pm, the contribution α increases in the range of 0 to 1, and when F=1 The degree of contribution α of the master cylinder pressure Pm is greater than the degree of contribution α when F=0.

In step S11, as shown in equation (1), the controller 9 calculates the final Target deceleration Gt.

Gt＝α·Gp+(1-α)·Gs ...(1)

According to Equation 1, as the value of the contribution degree α becomes larger, the contribution degree of the stroke amount Ss to the calculation of the final target deceleration Gt becomes smaller. At this time, the degree of contribution of the master cylinder pressure Pm increases. On the contrary, as the degree of contribution α becomes smaller, the degree of contribution of the stroke amount Ss to the calculation of the final target deceleration Gt becomes larger, and the degree of contribution of the master cylinder pressure Pm becomes smaller accordingly.

In subsequent step S12, the controller 9 calculates the target braking force required to obtain the final target deceleration Gt. At this time, the controller 9 separately calculates, for example, the front wheel braking force and the rear wheel braking force, and ideally distributes them. In subsequent step S13, the controller 9 drives and controls the gate valves 4f, 4r, the inlet valves 5FL to 5RR, the outlet valves 6FL to 6FR and the pumps 7f, 7r, respectively.

As described above, the stroke sensor 10 corresponds to the stroke amount detection section (means), the pressure sensor 11 corresponds to the pressure detection section (means), the processing of step S10 corresponds to the contribution degree setting section (means), and steps S5 to S8 The processing of corresponds to the sudden operation detection section (means).

Next, the operation, action and advantages of the first embodiment of the braking force control device will be described. Suppose, the usual brake-by-wire is now implemented. That is, when the gate valves 4f, 4r are closed, the inlet valves 5FL to 5RR, the outlet valves 6FL to 6RR, and the pumps 7f, 7r are drive-controlled, and braking force control is performed according to the braking operation of the driver of the motor vehicle.

That is, the controller 9 calculates the target deceleration Gs based on the stroke amount Ss, and calculates the target deceleration Gp based on the master cylinder pressure Pm (steps S2 and S3), and calculates the final target deceleration from these final decelerations Gs and Gp Gt (step S11), and brake force control is performed based on this final target deceleration Gt (steps S12 and S13). As shown in FIGS. 6A and 6B, the characteristics of the stroke simulator 8 are such that, when the driver of the motor vehicle desires a large deceleration, the brake pedal 1 is depressed more suddenly, and at the initial stage of depressing the pedal, The flow rate of the brake fluid from the master cylinder 2 to the stroke simulator 8 is limited due to the flow resistance of the flow channel 12 . Therefore, the master cylinder pressure Pm becomes larger than the master cylinder pressure when the driver of the motor vehicle gradually depresses the brake pedal. Furthermore, the pedal travel will not be greater than desired.

Therefore, at the initial stage of depressing the pedal when the driver performs a sudden brake operation, the contribution of the stroke amount Ss becomes large, and the final target deceleration Gt is calculated. At this time, the degree of contribution of the increase in the master cylinder pressure Pm to the increase in the final target deceleration Gt becomes small. Therefore, as shown in FIGS. 7A to 7C , these figures show the operation of the comparative example in the case where the contribution of the increase in the master cylinder pressure Pm to the increase in the final target deceleration Gt becomes small, as In the above-mentioned first embodiment, although the driver of the motor vehicle suddenly depresses the brake pedal 1 in order to obtain a large deceleration, the stroke of the brake pedal 1 cannot be as expected due to the flow resistance of the flow channel 12. proceed that way. In the initial stage of depressing the brake pedal 1, the final target deceleration Gt does not increase to the extent desired by the driver of the motor vehicle (refer to FIG. 7C), and does not accurately reflect the driver's intention.

Therefore, when a sudden brake operation by the driver of the motor vehicle is detected (when the control flag F is reset to "1"), the degree of contribution α of the master cylinder pressure Pm to the calculation of the final deceleration Gt is set to be larger than when no detection is made. The contribution to the driver's sudden brake operation (no sudden brake operation detected) (when the control flag F is reset to "0"), and as the master cylinder pressure Pm increases, is used to calculate the final The degree of contribution α of the master cylinder pressure Pm to the target deceleration Gt becomes larger. In other words, the degree of contribution of the master cylinder pressure Pm becomes larger (step S10).

Note that FIG. 8 shows calculation processing of the final target deceleration Gt in the first embodiment. Therefore, as shown in FIGS. 9A to 9C (especially FIG. 9C ), when the master cylinder pressure Pm becomes large due to the sudden braking operation performed by the driver of the motor vehicle, the increase in the final target deceleration Gt is improved. By reducing the arrival time to a predetermined deceleration, the delay in deceleration of the motor vehicle can be improved. Therefore, the final target deceleration Gt is increased to a value desired by the driver of the motor vehicle. From the initial stage of braking operation, the intention of the driver of the motor vehicle can be accurately reflected, and the effect of braking can be exhibited at an early stage of braking.

In addition, the controller 9 can detect the occurrence of a sudden braking operation by the driver of the motor vehicle when the controller 9 judges that the flow passage resistance of the flow passage 12 , which is the hydraulic transmission path of the master cylinder 2 , has increased. Therefore, this sudden braking operation can be accurately detected. That is, the controller 9 calculates the reference master cylinder pressure Pms from the stroke amount Ss detected by the stroke sensor 10 in step S4. If the deviation (Pm−Pms) between the reference master cylinder pressure Pms and the master cylinder pressure Pm detected by the pressure sensor 11 is equal to or greater than the predetermined value A1 (YES in step S5), The controller 9 can easily and accurately judge the occurrence of a sudden braking operation by the driver of the motor vehicle for the judgment of the increase of the flow passage resistance of the passage 12 .

Moreover, when the increase speed of the stroke Ss detected by the stroke sensor 10, that is, when the variation (Ss _{(n ) -Ss (n-1)} ) is equal to or greater than the predetermined value B (YES in step S7), the controller 9 judges that the driver of the motor vehicle has performed a sudden braking operation. Therefore, a sudden brake operation can be easily and accurately detected.

On the other hand, when the controller 9 does not detect a sudden brake operation (when the control flag F is reset to "0"), the contribution α for calculating the final target deceleration Gt becomes smaller than that detected by the controller 9 The contribution degree to the sudden brake operation of the motor vehicle driver (when the control flag F is set to "1"), and as the master cylinder pressure Pm becomes smaller, the contribution degree α becomes smaller, that is, the stroke amount Ss The degree of contribution increases (step S10). In this way, braking force control can be performed in accordance with the general tendency of motor vehicle drivers to try mainly to adjust the pedal stroke during the initial stage of pedaling.

When a failure such as a pump is detected from the state where the brake-by-wire is performed, the fail-safe structure opens the gate valves 4f, 4r, and the hydraulic pressure of the master cylinder 2 causes braking force to be generated. Note that, in the first embodiment described above, the processing of step S10 causes the degree of contribution α to continuously vary in unlimited stages in accordance with the master cylinder pressure Pm. The present invention is not limited thereto. The degree of contribution α may be changed in a stepwise manner or may be changed over one stage according to the master cylinder pressure Pm. In addition, this contribution degree α does not change linearly (in a curved shape) according to changes in the master cylinder pressure Pm. However, the present invention is not limited thereto. This degree of contribution α can be changed linearly in proportion to changes in the master cylinder pressure Pm.

In addition, the contribution degree α is used as an example of the distribution percentage (distribution ratio). The sum of α and (1-α) may not always be constant. For example, in such a way that one contribution is increased while the other is unchanged, and the sum can be increased accordingly. Furthermore, in the first embodiment, in step S10, the degree of contribution α is calculated from only the master cylinder pressure Pm. But the present invention is not limited thereto. That is, the contribution degree α may be calculated from only the stroke amount Ss, or may be calculated from both the stroke amount Ss and the master cylinder pressure Pm. In addition, although the sudden braking operation of the motor vehicle driver is detected by the "AND" condition between the judgment processing of step S5 and the judgment processing of step S7, the present invention is not limited thereto, and "or (OR)" condition.

In the above-mentioned first preferred embodiment, if in step S7, the change rate (amount) (Ss _{( n )} -Ss _(n-1) ) is equal to or greater than the predetermined value B, in other words, the change speed of the stroke amount Ss is equal to or greater than the predetermined value, then the controller 9 judges that a sudden braking operation by the driver of the motor vehicle occurs. However, the present invention is not limited thereto. The processing of step S7 may be changed to a new step S27 shown in FIG. 10 . That is, if the rate (amount) of change (Pm _(n) -Pm _{(n-1) ) of the master cylinder pressure Pm (n-1)} one sampling period before from the currently sampled master cylinder Pm _{(n )} is equal to or greater than the predetermined value C, in other words, if the change speed of the master cylinder pressure Pm is equal to or greater than the predetermined value, the controller 9 may judge that a sudden brake operation by the driver of the motor vehicle occurs. Therefore, a sudden braking operation by the driver of the motor vehicle can be accurately and easily detected in the same manner as the braking force control routine shown in FIG. 2 .

In the first embodiment, a hydraulic braking system is employed in which hydraulic pressure is the transmission medium. However, the present invention is not limited thereto. Pneumatic braking systems can be used in which compressed air is the transmission medium. Furthermore, in the first embodiment, brake-by-wire using hydraulic pressure is implemented. However, the present invention is not limited thereto. Since brake-by-wire can implement braking force control, as long as an electrically controllable energy source such as electric braking or regenerative motor braking is provided, any braking can be used. In electric braking, the drive controls the motor to operate The actuator clamps the disc rotor with the brake shoe under pressure, and presses the brake shoe against the inner peripheral surface of the brake drum under pressure.

Next, a second preferred embodiment of the braking force control device according to the present invention will be described based on FIGS. 11 to 13 . The specific structure of the braking force control device in the second embodiment is the same as that in the first embodiment. In the second embodiment of the braking force control device according to the present invention, the master cylinder pressure Pm contribution α used to calculate the final target deceleration Gt is made larger than the controller 9 when the driver's sudden braking operation is predicted by the controller 9. 9 The contribution α when the driver's sudden brake operation occurs is not predicted. Therefore, in the second embodiment, the same processing as that described in the first embodiment is performed except that the braking force control routine of FIG. 2 is changed to the braking force control routine shown in FIGS. 11 and 12 . Note that detailed descriptions of steps with the same reference numerals as those shown in FIG. 2 will be omitted here.

First, in step S31 of FIG. 11 , the controller 9 judges whether the accelerator is on (ON), that is, whether the driver of the motor vehicle has performed an accelerator operation. If the accelerator operation is not performed at step S31 (NO), the procedure goes to step S38 which will be described later. On the other hand, if the accelerator operation is performed (the accelerator is ON), the procedure goes to step S32. In step S32, the controller 9 judges whether the accelerator manipulation amount decreases, that is, whether the accelerator release operation occurs. If the controller 9 judges that the accelerator release operation has not occurred in step S32 (NO), the procedure goes to step S33. On the other hand, if the controller 9 judges that an accelerator release operation has occurred in step S32 (YES), the procedure goes to step S34. In step S33, the controller 9 resets the control flag F to "0", and the procedure goes to step S37.

_In step S34, the controller 9 refers to the control map shown in the flowchart of FIG. The control map is set in the following manner: that is, the horizontal axis represents the vehicle speed V, and the vertical axis represents the threshold value V _R , then when the vehicle speed V is less than V ₁ (for example, 20km/h), the threshold value V _R remains at V _R1 (for example, 500mm/ seconds), when the vehicle speed V increases to between V ₁ and V ₂ (for example, 60km/h), the threshold V _R drops to between V _R1 and V _R2 (for example, 200mm/s), and when the vehicle speed V exceeds V ₂ , the threshold _VR remains at _VR2 . Note that V _R1 is the maximum release (return) speed determined according to the structure of the accelerator pedal (accelerator), that is, the return speed corresponding to the return speed of the accelerator pedal to the release position by the return spring after the depressing force of the accelerator pedal is released. value, and it may have margins of the order of -10%.

At the next step S35, the controller 9 judges whether or not the accelerator decreasing speed is equal to or greater than the threshold V _R . Note that the accelerator decrease speed is calculated from the rate of change of the value from one sampling time before the accelerator manipulation amount. Note that the result of the judgment in step S35 is accelerator deceleration < V _R (No), and the controller 9 judges that the driver of the motor vehicle did not perform a sudden accelerator release operation. Therefore, the controller 9 predicts that the subsequent sudden braking operation will not be performed, and the routine goes to step S33. On the other hand, if the judgment result of step S35 is that the accelerator decreasing speed ≥ V _R , the controller 9 judges that the driver's sudden accelerator return (release) operation is performed, and predicts that a subsequent sudden braking operation is performed, and the routine goes to Go to step S36.

In step S36, the controller 9 sets the control flag F to "1", and the procedure goes to step S37. In step S37, the controller 9 sets the temporary setting flag f F indicating the temporary setting state of the control flag _F to "1", and the routine returns to the predetermined main routine. On the other hand, in step S38, the controller 9 judges whether the brake is OFF, that is, whether the brake operation is not performed. If the braking operation is performed (NO), the procedure goes to step S51 shown in FIG. 12, which will be described later. On the other hand, if no brake operation has occurred (YES), the routine goes to step S39.

In step S39, the controller 9 judges whether or not the temporary setting flag f _F is set to "1". If the judgment result is f _F =0, the controller 9 judges that the accelerator operation must not be performed after, for example, the ignition switch is turned on, and the routine returns to the predetermined main routine. On the other hand, if the judgment result is f _F =1, the controller 9 judges that this moment (now) is after the accelerator operation is released, and the routine goes to step S40.

In step S40, the controller 9 counts the time from the moment when the accelerator operation is released to the moment when the brake operation is started, using a timer T (T=T+1). In subsequent step S41, the controller 9 sets the timer flag f _T representing the count start state with the timer T to "1" to represent the count start state with the timer T, and the routine returns to the predetermined main routine . On the other hand, in step S51 in FIG. 12, the controller 9 judges whether or not the timer flag f _T is set to "1". If the result of the judgment at step S51 is f _T =0, the controller 9 judges that the braking operation is not a braking operation after the accelerator release operation, and the procedure goes to step S59 which will be described later. On the other hand, if the result of judgment at step S51 is f _T =1 (Yes), the controller 9 judges that the braking operation is a braking operation after the accelerator operation is released, and the procedure goes to step S52.

In step S52, the controller 9 refers to the control map shown in the flowchart of FIG. 12 in which the threshold value Tc of the timer T is set according to the vehicle speed V. FIG. The control map _is set in _the following manner: that is, the horizontal axis is the vehicle speed V, and the vertical axis is the threshold value Tc. seconds) and Tc ₂ (for example, 0.5 seconds), and when the vehicle speed V exceeds V ₂ , the threshold Tc remains at Tc ₂ . Note that Tc ₁ is the time it takes for an average person to reflexively switch pedaling from accelerator pedal to brake pedal 1, and Tc ₂ is the time it takes even a slow-reflex (slow reaction) person to switch pedaling.

In subsequent step S53, the controller 9 judges whether the count value of the timer T is equal to or greater than the threshold Tc. If the result of the judgment in step S53 is T≧Tc (Yes), the brake operation is not started immediately after the release of the accelerator operation. Therefore, the controller 9 predicts that no sudden braking operation is performed, and the routine goes to step S54. If the result of the judgment in step S53 is T<Tc, the braking operation is started immediately after the accelerator release operation, so the controller 9 predicts that a sudden braking operation is performed, and the procedure goes to step S55.

In step S54, the controller 9 resets the control flag F to "0", and the procedure goes to step S56. In step S55, the controller 9 sets the control flag F to "1", and the procedure goes to step S56. In step S56, the timer T is reset to "0". In the subsequent step S57, the timer flag f _T is reset to "0". In subsequent step S58, the temporary setting flag f _F is reset to "0", and the procedure goes to step S10 described with reference to FIG. 2 .

On the other hand, in step S59, the controller 9 judges whether or not the control flag F is reset to "0". If the judgment result is F=1 (NO), the controller 9 has predicted that a sudden brake operation will occur, and the routine goes to step S10. On the other hand, if F=0 in step S59, the controller 9 judges that there is a possibility that a sudden brake operation will be detected from now on, and the procedure goes to step S2. As described above, the processing of steps S31 to S41 and the processing of steps S51 to S57 in FIG. 11 are included in the sudden operation detection section (means).

Next, the operation, actions and advantages of the second preferred embodiment of the motor vehicle braking force control device according to the present invention will be described. Assuming now that during the accelerator operation, the driver of the motor vehicle performs a sudden accelerator release operation (YES in step S35), then the controller 9 predicts that a sudden brake operation will occur subsequently, and sets the control flag F "1" as a temporary setting (step S36). In this way, when the controller 9 (in advance) predicts that a sudden brake operation will occur soon, the contribution α of the master cylinder pressure Pm becomes larger. Therefore, since the response is not started from the actual detection of the sudden braking operation, the response characteristic can be improved by the detection time. Therefore, the large deceleration desired by the driver can be accurately secured from the initial stage of the brake operation.

In addition, a sudden brake operation can be predicted at the stage when the accelerator release operation is performed before the actual brake operation is performed. Therefore, the response characteristics of the second embodiment are particularly excellent. The determination of whether or not sudden braking occurs is made based on whether or not the speed of decrease in accelerator operation is equal to or greater than the threshold value _VR . Therefore, it is possible to easily and accurately judge a sudden brake operation. Furthermore, as the vehicle speed V becomes faster, the threshold V _R of the accelerator reduction speed is set to a smaller value (step S34 ). In particular, it is possible to more easily improve the response characteristics in the high-speed range that has a great influence on the braking distance. Therefore, excellent response characteristics are exhibited for sudden braking operations in the high-speed range. Since the large deceleration desired by the driver of the motor vehicle is obtained from the initial stage, the braking distance can be kept as short as possible.

Then, the duration (depressing transition time) from the time when the accelerator operation is released to the time when the brake operation is started is calculated by the timer T (step S40 ). When the timer count value T at the moment of starting the brake operation is smaller than the threshold Tc (the determination result of step S53 is "No"), the controller 9 predicts that a sudden brake operation will be implemented from this moment, and sets the control flag F to is "1" (step S55).

In this case, the degree of contribution α of the master cylinder pressure Pm becomes larger accordingly at the timing when a sudden brake operation is predicted. Therefore, since the response is not started from the actual detection of the sudden braking operation, the response characteristic can be improved by the detection time. Therefore, from the initial stage when the brake operation is started, the large deceleration desired by the driver of the motor vehicle can be accurately obtained.

Furthermore, since the prediction is performed from the time when the brake operation is actually started, reliability can be improved compared to the case where the prediction is performed at the stage of the accelerator release operation. In addition, whether to perform a sudden braking operation is determined based on whether the count value of the timer T is smaller than the threshold value Tc. Therefore, it can be judged easily and accurately. Furthermore, as the vehicle speed V becomes faster, the threshold value Tc of the timer value T is set longer (step S52). In particular, it is easier to improve the response characteristics in the high-speed range that has a great influence on the braking distance. Therefore, good response characteristics are exhibited for sudden braking operations in the high-speed range. Obtaining in this way the high deceleration desired by the driver of the motor vehicle makes it possible to keep the braking distance as short as possible from the initial stage.

As described above, in the case of predicting the occurrence of a sudden brake operation based on the pedaling transition time (timer T), the reliability of the prediction is compared with that of performing a sudden brake deceleration at the moment when a sudden accelerator release operation is detected. The situation has improved. Therefore, even if a sudden accelerator release operation is detected, the count value of the timer T is equal to or greater than the threshold Tc (YES in step S53). At this time, the previously set (temporarily set) control flag F is reset to "0" in step S54. Therefore, while improving the response characteristics, the reliability of the prediction is not reduced.

Note that in the second embodiment, although a sudden accelerator release operation is detected from the decrease speed of the accelerator operation. But the present invention is not limited thereto. For example, the controller 9 may also detect a sudden accelerator release operation when the decreasing acceleration of the accelerator operation (decreasing acceleration) is equal to or greater than a threshold value. Furthermore, in the second embodiment, even if a sudden accelerator operation is detected, the control flag F is reset to "0" when the count value of the timer T is equal to or greater (longer than) the threshold value Tc. However, the present invention is not limited thereto. For example, even if the timer T is equal to or greater than the threshold Tc, the control flag F remains at F=1. Therefore, when calculating the contribution degree α, the control map as shown in FIG. 13 can be referred to. The control map shown in FIG. 13 is set so that the contribution degree α is set from the state of F=1 to the state of F=0 as the count value of the timer T becomes longer (increases). Therefore, the reliability of the prediction is not reduced while respecting the response characteristics.

Also, in the second embodiment, although a sudden brake operation is predicted from the sudden accelerator release operation and the pedaling time (timer value T). But the present invention is not limited thereto. For example, a sudden braking operation can be predicted from the relative relationship between the host motor vehicle and motor vehicles driving ahead of the host motor vehicle. That is, when the inter-vehicle distance to the preceding motor vehicle suddenly decreases from a state where the inter-vehicle distance is approximately constant, or when the inter-vehicle distance to the preceding motor vehicle is shorter than the shortest braking distance, there is Possibility of brake operation. Therefore, even in this case, since the control flag F is set to "1", the controller 9 can respond to the fact that the degree of contribution α of the master cylinder pressure Pm becomes large. Other actions, advantages, and application ranges of the present invention are the same as those described in the case of the above-mentioned first embodiment.

This application is based on the prior Japanese patent applications No. 2004-370827 filed in Japan on December 22, 2004 and No. 2005-160474 filed in Japan on May 31, 2005. The disclosure is hereby incorporated by reference.

Although the invention has been described above with reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Based on the above teachings, those skilled in the art can make modifications and changes to the above embodiments. The scope of the invention is defined by the following claims.

Claims (19)

1. braking force control method that is used for power actuated vehicle comprises:

The braking input media is set, and described braking input media can be by the motor vehicle operator manual operation;

Master cylinder is set, and described master cylinder is configured to according to the operation generation master cylinder pressure of motor vehicle operator to described braking input media;

According in the master cylinder pressure that produces in the path increment of described braking input media and the described master cylinder at least one, set the contribution degree of path increment of described braking input media and the contribution degree of described master cylinder pressure;

Target braking force according to described path increment contribution degree and described master cylinder pressure contribution degree computing machine motor vehicle; It is characterized in that,

According to the braking force of the described target braking force controlling machine motor vehicle that calculates, the master cylinder pressure contribution degree when the master cylinder pressure contribution degree that is used to calculate described target braking force during with the unexpected brake operating that detects motor vehicle operator is set at greater than the unexpected brake operating that does not detect motor vehicle operator.

2. gradual braking device that is used for power actuated vehicle comprises:

The braking input media, it can be by the motor vehicle operator manual operation;

Master cylinder, it is configured to according to motor vehicle operator the operation of described braking input media be produced master cylinder pressure;

The contribution degree setting section, it is according in the master cylinder pressure that produces in the path increment of described braking input media and the described master cylinder at least one, sets the contribution degree of path increment of described braking input media and the contribution degree of described master cylinder pressure;

The target braking force calculating section, its path increment contribution degree and described master cylinder pressure contribution degree according to described braking input media is come the target braking force of computing machine motor vehicle; It is characterized in that described gradual braking device also comprises:

The brake-power control part, it comes the braking force of controlling machine motor vehicle according to the described target braking force that calculates, the master cylinder pressure contribution degree when described contribution degree setting section is used to calculate described target braking force in the time of will detecting the unexpected brake operating of motor vehicle operator master cylinder pressure contribution degree is set at greater than the unexpected brake operating that does not detect motor vehicle operator.

3. the gradual braking device that is used for power actuated vehicle according to claim 2, wherein,

Described gradual braking device also comprises:

The path increment test section, it detects the path increment of described braking input media;

The pressure detection part, it detects the master cylinder pressure that produces in described master cylinder; And

Unexpected operation detection part, it detects the unexpected brake operating that motor vehicle operator whether occurs, and,

Described target braking force calculating section calculates target braking force according to the contribution degree of the master cylinder pressure that produces in the contribution degree of the path increment of master cylinder pressure that produces in the path increment of described braking input media, the described master cylinder and described braking input media and the described master cylinder.

4. the gradual braking device that is used for power actuated vehicle according to claim 3, wherein,

Described unexpected operation detection partly increases by the flow passage resistance force of waterproof in the fluid pressure transfer path of judging described master cylinder, detects the unexpected brake operating of motor vehicle operator.

5. the gradual braking device that is used for power actuated vehicle according to claim 4, wherein,

Described unexpected operation detection part is divided according to the detected path increment calculating in described path increment test section benchmark master cylinder pressure, and when the deviation between the master cylinder pressure that described benchmark master cylinder pressure and described pressure detecting portion branch detect is equal to or greater than predetermined value, judge that the flow passage resistance force of waterproof in the fluid pressure transfer path of described master cylinder increases.

6. the gradual braking device that is used for power actuated vehicle according to claim 3, wherein,

Described unexpected operation detection part divides the gathering way of master cylinder pressure that detects according to described pressure detecting portion branch to be equal to or greater than predetermined value, detects the unexpected brake operating of motor vehicle operator.

7. the gradual braking device that is used for power actuated vehicle according to claim 3, wherein,

Described unexpected operation detection part branch is equal to or greater than predetermined value according to gathering way of the detected path increment in described path increment test section, detects the unexpected brake operating of motor vehicle operator.

8. the gradual braking device that is used for power actuated vehicle according to claim 3, wherein,

The unexpected brake operating of motor vehicle operator partly appears in described unexpected operation detection by prediction, detect the unexpected brake operating of motor vehicle operator.

9. the gradual braking device that is used for power actuated vehicle according to claim 8, wherein,

Described unexpected operation detection part is when detecting the flat-out acceleration device releasing operation of motor vehicle operator, and the unexpected brake operating of motor vehicle operator appears in prediction.

10. the gradual braking device that is used for power actuated vehicle according to claim 9, wherein,

Described unexpected operation detection part divide according in the acceleration/accel of the speed of accelerator releasing operation and accelerator releasing operation any one or the two be equal to or greater than predetermined threshold, detect the flat-out acceleration device releasing operation of motor vehicle operator.

11. the gradual braking device that is used for power actuated vehicle according to claim 10, wherein,

Along with the speed of a motor vehicle accelerates, described predetermined threshold is set to and diminishes.

12. the gradual braking device that is used for power actuated vehicle according to claim 9, wherein,

When responding described unexpected operation detection part branch, described contribution degree setting section predicts the brake operating that appearance is unexpected according to the flat-out acceleration device releasing operation of motor vehicle operator, and the described master cylinder pressure contribution degree that will be used to calculate described target braking force is set at when bigger, along with discharge from motor vehicle operator accelerator operation the time to be carved into the time length in the moment that the brake operating of motor vehicle operator begins elongated, be used to calculate the more approaching such state of described master cylinder pressure contribution degree of described target braking force: the state of described unexpected operation detection part when the unexpected brake operating of motor vehicle operator appears in prediction.

13. the gradual braking device that is used for power actuated vehicle according to claim 8, wherein,

When the time length in the moment that the brake operating that is carved into motor vehicle operator when motor vehicle operator discharges accelerator operation begins was shorter than predetermined threshold, described unexpected operation detection partly doped the unexpected brake operating of existing motor vehicle operator.

14. the gradual braking device that is used for power actuated vehicle according to claim 13, wherein,

Along with the speed of a motor vehicle accelerates, described predetermined threshold is set to bigger.

15. the gradual braking device that is used for power actuated vehicle according to claim 3, wherein,

Described gradual braking device also comprises:

The first desired deceleration calculating section, it calculates first desired deceleration (Gs) according to the detected path increment in described path increment test section (Ss);

The second desired deceleration calculating section, it calculates second desired deceleration (Gp) according to the master cylinder pressure (Pm) that described pressure detecting portion branch detects; And

Benchmark master cylinder pressure calculating section, it calculates benchmark master cylinder pressure (Pms) according to the detected path increment in described path increment test section (Ss),

Described unexpected operation detection part branch comprises the control mark setting section, described control mark setting section is when detecting the unexpected brake operating of motor vehicle operator, (F) is made as " 1 " with control mark, and when not detecting the unexpected brake operating of motor vehicle operator, (F) is reset to " 0 " with described control mark, and

Described contribution degree setting section is according to the state of described master cylinder pressure (Pm) and described control mark (F), sets the contribution degree (α) of the described master cylinder pressure (Pm) that is used to calculate ultimate aim deceleration/decel (Gt).

16. the gradual braking device that is used for power actuated vehicle according to claim 15, wherein,

Described gradual braking device also comprises ultimate aim deceleration/decel calculating section, described ultimate aim deceleration/decel calculating section calculates described ultimate aim deceleration/decel (Gt) according to the contribution degree (α) of described first desired deceleration (Gs), second desired deceleration (Gp) and described master cylinder pressure.

17. the gradual braking device that is used for power actuated vehicle according to claim 16, wherein,

Described target braking force calculating section calculates target braking force, to obtain ultimate aim deceleration/decel (Gt).

18. the gradual braking device that is used for power actuated vehicle according to claim 15, wherein,

Described contribution degree setting section is set described path increment (Ss) contribution degree and described master cylinder pressure (Pm) contribution degree that is used to calculate ultimate aim deceleration/decel (Gt) in such a way, described mode is: according to the increase of described master cylinder pressure (Pm) and the contribution degree (α) of described master cylinder pressure is increased to 1 from 0, and the described master cylinder pressure contribution degree of the described master cylinder pressure contribution degree (α) when described control mark (F) is set to " 1 " when being reset to " 0 " than described control mark (F) is big.

19. motor vehicle brake force control device according to claim 16, wherein, described ultimate aim deceleration/decel calculating section is calculated as follows ultimate aim deceleration/decel (Gt):

Gt＝α·Gp+(1-α)·Gs。

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