JP7371555B2 - Vehicle deceleration calculation device - Google Patents

Description

The present disclosure relates to a vehicle deceleration calculation device.

The applicant has developed a device as described in Patent Document 1 so that zero point drift error is reduced in a deceleration calculation device used for rear wheel floating suppression control. Specifically, the deceleration calculation device includes an "acquisition unit that acquires the detection signal from the deceleration sensor as the detected deceleration" and a "deceleration unit that calculates the deceleration of the vehicle based on the rotational speed of the vehicle's wheels." and a "compensation unit that determines an integrated deceleration that is a deceleration to be applied to rear wheel floating suppression control based on the detected deceleration and the calculated deceleration." Then, in the compensation section, the calculated deceleration when the time change amount of the detected deceleration and the time change amount of the calculated deceleration match is determined as the reference deceleration, and the time change amount of the detected deceleration is set to the reference deceleration. are sequentially integrated to calculate the integrated deceleration.

Although the above acquisition unit acquires the detected deceleration based on the detection signal from the deceleration sensor, the detection signal may be affected by pitching motion of the vehicle. Specifically, the detection signal of the deceleration sensor may be detected as a value larger than the true value depending on the occurrence of the pitch rate. Further, in the above calculation unit, the deceleration of the vehicle (calculated deceleration) is calculated based on the wheel speed, but the wheel speed may be affected by road surface disturbances (for example, road surface irregularities). Therefore, in the deceleration calculation device, it is desired to compensate for errors caused by pitching motion, road surface disturbance, and the like.

Patent Application No. 2020-012146

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle deceleration calculation device that can compensate for error effects caused by pitching motion during braking, road surface disturbances, and the like.

The vehicle deceleration calculation device according to the present invention compensates for the zero point drift of the detected deceleration (Gx) detected by the deceleration sensor (GX) provided on the body of the vehicle. a calculation unit (XE) that calculates the deceleration of the vehicle as a calculated deceleration (Ge) based on the wheel speed (Vw) that is the rotational speed (Vw) of the vehicle wheels; a compensation unit (XH) that compensates for the zero point drift based on the coincidence between the detected gradient (dGx), which is the amount of time change in the calculated deceleration (Ge), and the calculated gradient (dGe), which is the amount of time change in the calculated deceleration (Ge) , is provided. Then, the compensation unit (XH) determines that "the detected gradient (dGx) is greater than or equal to the first gradient (dgx)" and "that the calculated gradient (dGe) is greater than or equal to the second gradient (dge)." and a delay unit (XT) that delays the matching determination when at least one of the following is satisfied.

In the vehicle deceleration calculation device according to the present invention, the delay unit (XT) prohibits the matching determination for a prohibited time (ty). The compensator (XH) also calculates a difference between a detected slope (dGx), which is the amount of time change of the detected deceleration (Gx), and a calculated gradient (dGe), which is the amount of time change of the calculated deceleration (Ge). The matching is determined based on the fact that (hD) is less than the monitored deviation (Hx) for a monitoring time (Tk), and the delay unit (XT) adjusts the monitored deviation (Hx) Perform at least one of a modification that decreases and a modification that increases the monitoring time (Tk).

If the detected gradient dGx is greater than or equal to the first gradient dgx, there is a high probability that the detected deceleration Gx is affected by the pitching motion of the vehicle. Further, when the calculated gradient dGe is equal to or greater than the second slope dge, there is a high probability that the calculated deceleration Ge is affected by road surface disturbance. According to the above configuration, the match determination is delayed in at least one of "dGx≧dgx" and "dGe≧dge". Therefore, errors caused by pitching motion (behavior), road surface disturbance, etc. can be suitably compensated for (eliminated).

FIG. 1 is an overall configuration diagram for explaining a vehicle equipped with a deceleration calculation device GH according to the present invention. FIG. 2 is a block diagram for explaining calculation processing of the deceleration calculation device GH. FIG. 3 is a flow diagram for explaining a first processing example in a compensation unit XH. FIG. 7 is a flowchart for explaining a second processing example in the compensation unit XH.

<Symbols of component parts, etc., subscripts at the end of the symbol>
In the following description, components, arithmetic processing, signals, characteristics, and values having the same symbol, such as "CW", have the same function. The suffixes "f" and "r" added to the end of each symbol are comprehensive symbols indicating which symbol the symbol refers to in the longitudinal direction of the vehicle. Specifically, "f" indicates the front wheel, and "r" indicates the rear wheel. For example, the wheels are expressed as a front wheel WHf and a rear wheel WHr. Furthermore, the subscripts "f" and "r" at the end of the symbol may be omitted. When the subscripts "f" and "r" are omitted, each symbol represents its generic name. For example, "CWf" represents a front wheel cylinder, "CWr" represents a rear wheel cylinder, and "CW" represents a front wheel, rear wheel cylinder. In addition, in the connection path HS, the side closer to the master cylinder CM is called the "upper", and the side closer to the wheel cylinder CW is called the "lower".

<Vehicle equipped with deceleration calculation device GH according to the present invention>
A vehicle equipped with a vehicle deceleration calculation device GH according to the present invention will be described with reference to the overall configuration diagram of FIG. The vehicle is assumed to be a motorcycle (also referred to as a "motorcycle"). A vehicle employs two fluid paths (ie, two braking systems). In one of the two braking systems, a front wheel master cylinder CMf is connected to a front wheel cylinder CWf via a front wheel connection path HSf. In the other of the two braking systems, a rear wheel master cylinder CMr is connected to a rear wheel cylinder CWr via a rear wheel connection path HSr. Here, the front wheel and rear wheel connecting paths HSf and HSr (=HS) are fluid paths. The "fluid path" is a path for moving the brake fluid BF, which is a working fluid, and includes brake piping, a flow path of the fluid unit HU, a hose, and the like.

The vehicle is equipped with a brake operation member BP (=BPf, BPr), a wheel cylinder CW (=CWf, CWr), a master cylinder CM (=CMf, CMr), and a brake control device SC.

The brake operation member BP is a member operated by the driver to decelerate the vehicle. For example, a brake lever is used as the front wheel brake operation member BPf, a brake pedal is used as the rear wheel brake operation member BPr, and in a scooter, a brake lever is used as both the brake operation members BPf and BPr. Ru. By operating the brake operation member BP, the hydraulic pressures (front and rear wheel cylinder hydraulic pressures) Pwf and Pwr in the front and rear wheel cylinders CWf and CWr (=CW) are adjusted. As a result, front wheel and rear wheel braking torques Tqf and Tqr (=Tq) are adjusted, and front and rear wheel braking forces Fxf and Fxr (=Fx) are generated. Here, the front wheel and rear wheel cylinder hydraulic pressures Pwf and Pwr are also referred to as "front wheel and rear wheel braking hydraulic pressures Pwf and Pwr (=Pw)."

Front wheel and rear wheel rotating members KTf and KTr (=KT) are fixed to wheels WH (=WHf, WHr) of the vehicle. Front wheel and rear wheel brake calipers CPf and CPr (=CP) are arranged so as to sandwich the rotating member KT (for example, a brake disc). The brake caliper CP is provided with a wheel cylinder CW, and by increasing the pressure of the brake fluid BF (braking fluid pressure) Pw inside the wheel cylinder CW, a friction member (for example, a brake pad) is pressed against the rotating member KT. . Since the rotating member KT and the wheel WH are fixed so as to rotate integrally, the braking torque Tq is generated at the wheel WH due to the frictional force generated at this time. This braking torque Tq generates a braking force Fx on the wheel WH.

Front and rear wheel hydraulic pressure chambers Rmf and Rmr (=Rm) are formed inside the front and rear wheel master cylinders CMf and CMr (=CM). When the brake operation member BP is operated, the volume of the hydraulic chamber Rm is reduced, and the brake fluid BF is force-fed from the hydraulic chamber Rm to the wheel cylinder CW via the connection path HS. That is, the hydraulic pressure Pw of the wheel cylinder CW is increased by the hydraulic pressure Pm of the master cylinder CM (referred to as "master cylinder hydraulic pressure").

Furthermore, the vehicle is equipped with front wheel and rear wheel speed sensors VWf, VWr (=VW), and a longitudinal acceleration sensor (also referred to as a "deceleration sensor") GX. Front wheel and rear wheel speeds Vwf and Vwr (=Vw) are detected by wheel speed sensors VW provided on each wheel WH. A deceleration sensor GX provided on the body of the vehicle detects acceleration Gx in the longitudinal direction (progressing direction) of the vehicle (which is longitudinal acceleration and also referred to as "detected deceleration"). The signals of the wheel speed Vw and the detected deceleration Gx are used for anti-lock brake control to suppress the locking tendency of the wheels WH (that is, excessive deceleration slip), rear wheel lifting suppression control to suppress lift-up of the rear wheels WHr, etc. It is used for braking force control. The wheel speed Vw and longitudinal acceleration (detected deceleration) Gx detected by each sensor (such as VW) are input to a brake controller ECU (also simply referred to as "controller").

≪Brake controller ECU≫
The brake control device SC adjusts the brake fluid pressure Pw (result, braking force Fx) of the wheel WH based on the calculation result of the deceleration calculation device GH. The brake control device SC includes a brake controller ECU and a fluid unit HU. A brake controller (also referred to as an "electronic control unit") ECU is composed of an electric circuit board on which a microprocessor or the like is mounted, and a control algorithm programmed into the microprocessor.

A brake controller ECU (electronic control unit) controls (drives) the electric motor MT of the fluid unit HU and the solenoid valves VI, VO. Specifically, drive signals Vi and Vo for controlling the electromagnetic valves VI and VO are calculated based on a control algorithm within the microprocessor. Similarly, a drive signal Mt for controlling electric motor MT is calculated.

The controller ECU is equipped with a drive circuit to drive the electromagnetic valves VI and VO and the electric motor MT. In the drive circuit, a bridge circuit is formed by switching elements (power semiconductor devices such as MOS-FETs and IGBTs) to drive the electric motor MT. Based on the motor drive signal Mt, the energization state of each switching element is controlled, and the output of the electric motor MT is controlled. Further, in the drive circuit, the switching elements are driven based on the drive signals Vi and Vo, and the energization state (that is, the excitation state) of the electromagnetic valves VI and VO is controlled. The drive circuit is provided with an energization amount sensor that detects the actual energization amount of the electric motor MT and the solenoid valves VI, VO. For example, a current sensor is provided as the energization amount sensor to detect the current supplied to the electric motor MT and the electromagnetic valves VI and VO.

The brake controller ECU includes a deceleration calculation device GH. The deceleration calculation unit GH is an algorithm programmed into a microprocessor. The deceleration calculation device GH calculates, for example, a compensation deceleration Gh applied to the rear wheel floating suppression control based on the wheel speed Vw and the detected deceleration Gx. Details of the compensation deceleration Gh will be described later.

≪Fluid unit HU≫
The fluid unit HU is an actuator that individually controls the braking force Fx of the wheels WH. The front and rear wheel master cylinders CMf and CMr, the front and rear wheel hydraulic pressure chambers Rmf and Rmr, and the front and rear wheel cylinders CWf and CWr are the front and rear wheel connection paths (fluid paths) HSf and HSr (=HS ). In the connection path HS, a fluid unit HU is provided between the master cylinder CM and the wheel cylinder CW. The fluid unit HU includes an inlet valve VI, an outlet valve VO, an electric motor MT, a fluid pump HP, and a low pressure reservoir RW.

The front wheel and rear wheel inlet valves VIf and VIr (=VI) are normally open electromagnetic valves (for example, on-off valves) that close in response to energization. The inlet valve VI is provided in the middle of the connection path HS. The inlet valve VI is controlled based on a drive signal Vi from the controller ECU. The inlet valve VI allows movement of the brake fluid BF between the wheel cylinder CW and the master cylinder CM through the connection path HS when the valve is open, and is blocked when the valve is closed.

In the connection path HS, between the inlet valve VI and the wheel cylinder CW (that is, the lower part of the inlet valve VI), one end of the front wheel and rear wheel return paths HRf and HRr (=HR), which are fluid paths, is connected. Connected. The other end of the return path HR is located between the master cylinder CM and the inlet valve VI (i.e., the inlet valve VI (at the top of the screen). In other words, the return path HR is a fluid path that connects the upper part of the inlet valve VI and the lower part of the inlet valve VI in the connection path HS so as to bypass the inlet valve VI.

The front wheel and rear wheel outlet valves VOf, VOr (=VO) are normally closed electromagnetic valves (for example, on-off valves) that open in response to energization. The outlet valve VO is provided in the return path HR. The outlet valve VO is controlled based on a drive signal Vo from the controller ECU. The outlet valve VO allows the movement of the brake fluid BF from the wheel cylinder CW to the master cylinder CM side through the return path HR when the valve is opened, and is blocked when the valve is closed.

Front wheel and rear wheel fluid pumps HPf and HPr (=HP) are provided in front and rear wheel return paths HRf and HRr (=HR). Also, a low pressure reservoir RW is connected to the return path HR. In detail, the fluid pump HP is provided between the outlet valve VO and "the connection between the connection path HS and the return path HR at the upper part of the inlet valve VI." The low pressure reservoir RW is also connected to the return path HR between the outlet valve VO and the fluid pump HP.

The two fluid pumps HP are driven by one electric motor MT. Electric motor MT is controlled based on a drive signal Mt from a brake controller ECU. Braking fluid BF is pumped up from the low pressure reservoir RW or the wheel cylinder CW by the fluid pump HP and returned to the upper part of the inlet valve VI (for example, the hydraulic pressure chamber Rm of the master cylinder CM).

In order to reduce the hydraulic pressure (braking hydraulic pressure) Pw in the wheel cylinder CW by anti-lock brake control or rear wheel lifting suppression control, the inlet valve VI is placed in the closed position and the outlet valve VO is placed in the open position. Ru. The inflow of the brake fluid BF from the inlet valve VI is blocked, the brake fluid BF in the wheel cylinder CW flows out to the low pressure reservoir RW, and the brake fluid pressure Pw is reduced. Furthermore, in order to increase the brake fluid pressure Pw, the inlet valve VI is placed in the open position, and the outlet valve VO is placed in the closed position. The brake fluid BF is prevented from flowing out to the low pressure reservoir RW, the hydraulic pressure of the master cylinder CM (master cylinder hydraulic pressure) Pm is introduced into the wheel cylinder CW, and the brake hydraulic pressure Pw is increased. Furthermore, in order to maintain the hydraulic pressure (braking hydraulic pressure) Pw in the wheel cylinder CW, both the inlet valve VI and the outlet valve VO are closed. That is, by controlling the electromagnetic valves VI and VO, the braking fluid pressure Pw (that is, the braking torque Tq, and as a result, the braking force Fx) can be adjusted independently at the wheel cylinder CW of each wheel WH. .

<Calculation processing of deceleration calculation device GH>
The calculation processing in the deceleration calculation device GH will be explained with reference to the block diagram of FIG. For example, the calculation result Gh (referred to as "compensation deceleration") of the deceleration calculation device GH is applied to the brake control device SC including rear wheel lifting suppression control. The compensated deceleration Gh is obtained by compensating for the zero point drift error in the detected deceleration Gx (output result of the deceleration sensor GX). Note that the "rear wheel floating suppression control" avoids a situation in which the rear wheel WHr leaves the road surface (referred to as "rear wheel floating" or "rear wheel lift-up") by reducing the front wheel braking force Fxf. It is something.

The deceleration calculation device GH includes a control algorithm programmed in the controller ECU, and is composed of an acquisition section XA, a calculation section XB, and a compensation section XH. In addition, in the compensation deceleration Gh, the detected deceleration Gx, and the calculated deceleration Ge, which will be explained below, the value on the side that decelerates the vehicle is represented by a "plus sign (+)".

The acquisition unit XA acquires the detected deceleration Gx from the deceleration sensor GX. Specifically, in the controller ECU, first, the output (detection signal) of the deceleration sensor GX, which is an analog signal, is converted into a digital signal by an analog/digital conversion circuit. Then, the output of the deceleration sensor GX after analog/digital conversion is subjected to filter processing to obtain (determine) the detected deceleration Gx.

A calculation unit XB calculates a calculation deceleration Ge based on the wheel speed Vw. Specifically, the calculation unit XB first calculates the vehicle speed Vx based on the faster of the front wheel speed Vwf and the rear wheel speed Vwr. In calculating the vehicle speed Vx, a limit may be set on the amount of change over time. That is, an upper limit value αup of the increasing slope of the vehicle body speed Vx and a lower limit value αdn of the decreasing slope are set, and changes in the vehicle body speed Vx are restricted by the upper and lower limit values αup and αdn. Next, the vehicle speed Vx is time differentiated to calculate the calculated deceleration Ge. That is, in the calculation unit XB, the vehicle speed Vx is calculated based on the wheel speed Vw, and the calculated deceleration Ge is calculated based on the vehicle speed Vx.

The compensating section XH calculates a compensated deceleration Gh in which the zero point drift error is compensated based on the detected deceleration Gx and the calculated deceleration Ge. In the compensation unit XH, first, a time change amount dGx of the detected deceleration Gx and a time change amount dGe of the calculated deceleration Ge are calculated. Here, the amount of change over time dGx is also referred to as a "detected gradient" and is a time differential value of the detected deceleration Gx. The time change amount dGe is also called a "calculated gradient" and is a time differential value of the calculated deceleration Ge.

Next, the compensation unit XH determines whether "the amount of time change (detected gradient) dGx and the amount of time change (calculated gradient) dGe match or not." This determination is called "coincidence determination."

The compensation unit XH includes a delay unit XT so that a match determination (determination of match/mismatch between the detected gradient dGx and the calculated gradient dGe) is appropriately performed. In the delay unit XT of the compensation unit ≧dge''), the match determination is delayed. This processing is called "delay processing" or "compensation processing." On the other hand, if the detected gradient dGx is less than the first gradient dgx (i.e., "dGx<dgx") and the calculated gradient dGe is less than the second gradient dge (i.e., "dGe<dge"), there is a match. Judgment is not delayed. Here, the first and second gradients dgx and dge are predetermined values (constants) set in advance. Further, the magnitude relationship between the first gradient dgx and the second gradient dge may be the same value or may be different values.

<<First compensation processing example of delay section HT>>
For example, in the compensation unit This is done based on the fact that the amount has become less than the reference amount hx. Furthermore, "coincidence of detected gradient dGx and calculated gradient dGe" is defined as "the point in time (corresponding calculation The determination may be made based on the period). Here, the reference amount hx and the reference time tx are predetermined values (constants) set in advance.

On the other hand, in the compensation unit XH (in particular, the delay unit XT), if at least one of the conditions “dGx≧dgx” and “dGe≧dge” is satisfied, the process of matching determination reaches the prohibited time ty. It is not carried out across the board. That is, by prohibiting the match determination, the match determination is delayed by the prohibited time ty. Here, the prohibited time ty is a predetermined value (constant) set in advance.

<<Second compensation processing example of delay section HT>>
For example, in the compensation unit The determination can be made at a time point (corresponding calculation cycle) that continues for a time Tk. Here, the monitoring deviation Hx (deviation used for monitoring for matching determination) and the monitoring time Tk (time used for monitoring for matching determination) are defined as "comparison between detected gradient dGx and first gradient dgx". This value is determined based on at least one of the following: "result of calculation gradient dGe and second gradient dge".

When "dGx<dgx" and "dGe<dge", the monitoring deviation Hx and the monitoring time Tk each have a certain value (predetermined value, for example, the above reference value hx (reference amount), tx (reference time)). Then, in the compensation unit XH (in particular, the delay unit XT), when at least one of the conditions “dGx≧dgx” and “dGe≧dge” is satisfied, “the monitoring deviation Hx is set to a certain value ( For example, "modification that decreases the monitoring time Tk from a certain value (for example, the reference time tx, also called "initial time")" at least one of the following: "incremental modification" is performed. At least one of the correction to decrease the monitoring deviation Hx and the correction to increase the monitoring time Tk makes it difficult to determine whether the detected gradient dGx and the calculated slope dGe match, and as a result, the determination of coincidence is delayed.

《Calculation of compensation deceleration Gh》
In the compensation unit XH, the calculated deceleration Ge when the detected slope dGx and the calculated slope dGe match is determined as the reference deceleration gh. The compensation deceleration Gh based on the reference deceleration gh will be explained below. The compensation deceleration Gh is applied, for example, to the rear wheel lifting suppression control as the deceleration of the vehicle (vehicle body).

The compensation deceleration Gh is calculated by sequentially integrating the reference deceleration gh and the amount of time change (detected slope) dGx of the detected deceleration Gx at each calculation cycle. That is, in the next calculation cycle after the calculation cycle in which the reference deceleration gh was set, the compensation deceleration Gh is calculated using the following equation (1). Note that in the following formula, [n] corresponds to the current calculation cycle, and [n-1] represents a state quantity (variable) corresponding to the previous calculation cycle.
Gh[n]=gh+dGx[n]...Formula (1)

After the first compensation deceleration Gh is calculated, the detected slope dGx[n] of the current calculation cycle is added to the compensation deceleration Gh[n-1] of the previous calculation cycle, and the compensation deceleration Gh[n] is calculated. is calculated. That is, as shown in Equation (2), the detected gradient dGx[n] is sequentially added to the compensation deceleration Gh[n-1] every calculation cycle to calculate the compensation deceleration Gh[n].
Gh[n]=Gh[n-1]+dGx[n]...Formula (2)

In the rear wheel floating suppression control, the front wheel braking force Fxf is reduced when the compensation deceleration Gh (deceleration of the vehicle body) becomes equal to or higher than the predetermined deceleration gx. Here, the predetermined deceleration gx is a preset control threshold (predetermined constant).

The detected deceleration Gx includes an error of zero point drift. However, since the detected gradient dGx is the amount of change with respect to time, it does not include the error of zero point drift. The deceleration calculating device GH calculates the compensation deceleration Gh by sequentially integrating the detected gradient dGx every calculation cycle. Therefore, the compensation deceleration Gh compensates for the zero point drift error.

Since the calculated deceleration Ge is calculated based on the wheel speed Vw, it is affected by the deceleration slip of the wheel WH (the slip in the rotational direction of the wheel WH, which is the difference between the vehicle body speed Vx and the wheel speed Vw). In particular, when the rear wheel floating suppression control is executed, the deceleration slip is likely to increase because the braking is sudden and the vehicle body deceleration is large. In order to avoid being affected by the deceleration slip of the wheels WH, the deceleration calculating device GH sets the calculated deceleration Ge when the detected slope dGx and the calculated slope dGe match as a reference value (reference deceleration) gh, and then performs the detection. Integration of the gradient dGx is started.

The determination of whether the detected gradient dGx and the calculated gradient dGe match is delayed if at least one of "dGx≧dgx" and "dGe≧dge" applies. When the detected gradient dGx is greater than or equal to the first gradient dgx (predetermined value), there is a probability that the detected deceleration Gx is influenced by the pitching movement (pitch rate) of the vehicle and is output as a value larger than the true value. is high. Furthermore, when the calculated gradient dGe is equal to or higher than the second slope dge (predetermined value), the calculated deceleration Ge is affected by road surface disturbances (for example, road surface irregularities) and is calculated as a value larger than the true value. There is a high probability that there is. Since such a situation does not last long, the match determination is delayed in at least one of "dGx≧dgx" and "dGe≧dge". By this delay processing, errors caused by pitching motion (behavior of the vehicle body during braking), road surface disturbance, etc. can be appropriately compensated for (eliminated) in the computation of the compensation deceleration Gh.

<First processing example of compensation unit XH>
A first example of processing (compensation processing) in the compensation unit XH (particularly the delay unit XT) will be described in detail with reference to the flowchart in FIG. 3. Regarding the relationship between FIG. 2 and FIG. 3, step S110 corresponds to the acquisition section XA and calculation section XB, and steps S120 to S160 correspond to the compensation section XH.

In step S110, detected deceleration Gx is acquired from deceleration sensor GX. Further, in step S110, the vehicle speed Vx is calculated based on the wheel speed Vw, and the calculated deceleration Ge is calculated based on the vehicle speed Vx. In step S120, a time change amount (detection slope) dGx of the detected deceleration Gx and a time change amount (calculation slope) dGe of the calculated deceleration Ge are calculated.

In step S130, it is determined whether "the delay condition is satisfied or not" based on at least one of the detected gradient dGx and the calculated gradient dGe. Specifically, if at least one of "the detected gradient dGx is greater than or equal to the first gradient dgx" and "the calculated gradient dGe is greater than or equal to the second gradient dge" is satisfied, step The determination in S130 is affirmative, and the process proceeds to step S140. On the other hand, if both the conditions of "the detected gradient dGx is less than the first gradient dgx" and "the calculated gradient dGe is less than the second gradient dge" are satisfied, the determination in step S130 is negative. The process then proceeds to step S150. Note that the first and second gradients dgx and dge are predetermined values (constants) set in advance, and the magnitude relationship between the first gradient dgx and the second gradient dge may be the same value, It may be a different value.

In step S140, a process (referred to as "prohibition process") for prohibiting determination of coincidence between the detected gradient dGx and the calculated gradient dGe is executed. Specifically, in step S140, the time T is counted (integrated) from the time when the determination process in step S130 is affirmed for the first time (the calculation cycle corresponding to the time when the state is switched from the negative state to the positive state in step S130). be done. Then, until the accumulated time T reaches the prohibited time ty, the process (match determination) of step S150, which will be described later, is not performed (that is, prohibited). That is, the match determination is prohibited and delayed for the prohibited time ty. Here, the prohibited time ty is a predetermined value (constant) set in advance. Note that in the first processing example, step S140 corresponds to the delay unit XT in FIG.

In step S150, it is determined whether or not the detected gradient dGx and the calculated gradient dGe match (match determination) based on the comparison between the detected gradient dGx and the calculated gradient dGe. For example, the coincidence determination is made when the comparison result (gradient deviation) hD (=|dGx−dGe|) between the detected gradient dGx and the calculated gradient dGe is less than the reference amount hx. Alternatively, the coincidence determination may be performed at the point in time (corresponding calculation cycle) when the state of "hD<hx" continues for a reference time tx (predetermined time). Note that the reference amount hx and the reference time tx are predetermined values set in advance.

If it is denied in step S150 that the detected gradient dGx and the calculated gradient dGe match, the process returns to step S110. On the other hand, if it is determined in step S150 that the detected gradient dGx and the calculated gradient dGe match, the process proceeds to step S160.

In step S160, compensation deceleration Gh is calculated. The compensated deceleration Gh is a state variable (state quantity) that expresses the deceleration of the vehicle body, with the zero point drift of the detected deceleration Gx compensated for. Specifically, in step S160, the calculated deceleration Ge at the time when the determination process in step S150 is affirmed for the first time (the calculation cycle corresponding to the time when the negative state is switched to the positive state in step S150) is determined to be the standard. It is calculated as deceleration gh. In the calculation cycle immediately after that, the detected gradient dGx is added to the reference deceleration gh. Then, in each calculation cycle, the detected slope dGx is sequentially added to the previous compensation deceleration Gh, and the detected gradient dGx is determined as the compensation deceleration Gh in the corresponding calculation cycle (i.e., the current one) (the above formula (1) (See 2)).

In addition, in step S160, the deviation hG (" The compensation deceleration Gh may be calculated based on the deceleration deviation (referred to as "deceleration deviation"). The deceleration deviation hG corresponds to the zero point drift component of the detected deceleration Gx. Therefore, the compensation deceleration Gh can be calculated by subtracting the deceleration deviation hG from the detected deceleration Gx (ie, "Gh=Gx-hG").

The detected deceleration Gx includes a zero point drift, but the detected gradient dGx does not include this error. Further, since the wheel speed Vw includes deceleration slip, the calculated deceleration Ge becomes oscillatory, and the calculated gradient dGe fluctuates. "A match between the detected gradient dGx and the calculated gradient dGe" means that the fluctuation of the calculated deceleration Ge has converged. Therefore, the deceleration calculating device GH calculates the compensation deceleration Gh based on the deceleration Ge (calculated deceleration) and Gx (detected deceleration) when the detected slope dGx and the calculated slope dGe match. Therefore, in the compensation deceleration Gh, the influence of errors caused by zero point drift and deceleration slip can be compensated for.

In addition, in the deceleration calculation device GH, when the detected gradient dGx is greater than or equal to the first gradient dgx, the above-mentioned determination of coincidence is delayed by being prohibited for a predetermined prohibition time ty. be done. Similarly, even when the calculated gradient dGe is greater than or equal to the second gradient dge, the above-described matching determination is delayed by being prohibited for a predetermined prohibition time ty. In the case of "dGx≧dgx", there is a possibility that the detected deceleration Gx is influenced by the pitching behavior. Further, in the case of "dGe≧dge", there is a possibility that the calculated deceleration Ge is influenced by the road surface disturbance. Since these error effects are eliminated in a short time, at least one of the following is satisfied: the detected gradient dGx is greater than or equal to the first gradient dgx, and the calculated gradient dGe is greater than or equal to the second gradient dge. In this case, the determination of a match is delayed. In other words, if the detected gradient dGx is less than the first gradient dgx and the calculated gradient dGe is less than the second gradient dge, the above coincidence is determined without delay. Therefore, in the compensation deceleration Gh, error effects caused by pitching behavior (particularly, pitch rate) and road surface disturbances (particularly, road surface level differences) can be appropriately compensated.

<Second processing example of compensation unit XH>
A second example of processing (compensation processing) in the compensation section XH (particularly the delay section XT) will be described in detail with reference to the flowchart of FIG. 4. In the first processing example, a prohibition process for a prohibition time ty (see step S140) is adopted as a delay process for matching determination (processing by the delay unit XT). In the second processing example, instead of the prohibition process, a process that makes it difficult for a match to be determined is adopted. Regarding the relationship between FIG. 2 and FIG. 4, step S210 corresponds to the acquisition section XA and the calculation section XB, and steps S220 to S260 correspond to the compensation section XH.

The processing in step S210 and step S220 is the same as the processing in step S110 and step S120, so the description thereof will be omitted. In step S230, similarly to step S130, it is determined whether "the delay condition is satisfied or not" based on at least one of the detected gradient dGx and the calculated gradient dGe. That is, if at least one of "the detected gradient dGx is greater than or equal to the first gradient dgx" and "the calculated gradient dGe is greater than or equal to the second gradient dge" is true, the determination in step S230 is made. is affirmed, and the process proceeds to step S240. On the other hand, if the two conditions of "the detected gradient dGx is less than the first gradient dgx" and "the calculated gradient dGe is less than the second gradient dge" are satisfied, the determination in step S230 is If the answer is NO, the process proceeds to step S250. Similar to the first processing example, the first and second gradients dgx and dge are preset predetermined values (constants), and the magnitude relationship between the first gradient dgx and the second gradient dge is the same value. may exist, or may have different values.

In step S240, values Hx (monitoring deviation) and Tk (monitoring time) that are used for monitoring the match determination in step S250, which will be described later, are calculated. Specifically, in step S240, the monitoring deviation Hx is decreased at the time when the determination process in step S230 is affirmed for the first time (the calculation cycle corresponding to the time when the state is switched from the negative state to the positive state in step S230). The monitoring time Tk is modified to increase the monitoring time Tk. The monitoring deviation Hx is set to a value hx (a reference amount and a predetermined value set in advance) as an initial value, and is adjusted to decrease from there. Further, the monitoring time Tk is set to a value (reference time) tx (a predetermined value set in advance) as an initial value, and is adjusted to increase from there. That is, in step S240, the monitoring deviation Hx is made smaller than the initial value hx (reference amount), and the monitoring time Tk is made longer than the initial value tx (reference time).

The amount of decrease in the monitoring deviation Hx is preset to a predetermined value. Alternatively, the amount of decrease in the monitoring deviation Hx may be increased as the slopes dGx and dGe become larger. Furthermore, the amount of increase in the monitoring time Tk is also preset to a predetermined value. Alternatively, the amount of increase in the monitoring time Tk may be increased as the gradients dGx and dGe become larger. Note that in the second processing example, step S240 corresponds to the delay unit XT in FIG.

In step S250, it is determined whether or not the detected gradient dGx and the calculated gradient dGe match (match determination) based on the comparison between the detected gradient dGx and the calculated gradient dGe. Specifically, a match is determined when a state in which the comparison result (gradient deviation) hD (=|dGx−dGe|) between the detected gradient dGx and the calculated gradient dGe is less than the monitoring deviation Hx continues over the monitoring time Tk. It is performed at the point in time when it is continued (the corresponding calculation cycle).

In step S250, if it is denied that the detected gradient dGx and the calculated gradient dGe match, the process returns to step S210. On the other hand, if it is determined in step S250 that the detected gradient dGx and the calculated gradient dGe match, the process proceeds to step S260. In step S260, compensation deceleration Gh is calculated using a method similar to step S160.

In the second processing example, the state in which the deviation hD between the detected gradient dGx (the amount of time change in the detected deceleration Gx) and the calculated slope dGe (the amount of time change in the calculated deceleration Ge) is less than the monitoring deviation Hx is the monitoring time Tk. Based on the fact that the detected gradient dGx and the calculated gradient dGe match, it is determined that the detected gradient dGx and the calculated gradient dGe match. If at least one of "the detected gradient dGx is greater than or equal to the first gradient dgx" and "the calculated gradient dGe is greater than or equal to the second gradient dge" is satisfied, in step S240 , the monitoring deviation Hx and the monitoring time Tk are adjusted so that it becomes difficult to judge whether they match. As a result, the coincidence determination is delayed, and as in the first processing example, errors caused by pitching motion, road surface disturbance, etc. can be compensated for.

In the second processing example, either the correction to decrease the monitoring deviation Hx or the correction to increase the monitoring time Tk may be omitted. Therefore, in the second processing example, at least one of a modification to decrease the monitoring deviation Hx and a modification to increase the monitoring time Tk is executed. Even in this case, since the match determination is delayed, the same effect as described above can be achieved.

<Other embodiments>
Other embodiments will be described below. Other embodiments also provide the same effects as described above (compensation for errors caused by pitching behavior, road surface disturbance, etc.).

In the above embodiment, a motorcycle is employed as the vehicle, and the deceleration calculation device GH is applied. Alternatively, the deceleration calculation device GH can also be applied to four-wheeled vehicles (passenger cars, trucks, etc.). However, the deceleration calculation device GH is more effective in motorcycles that are susceptible to pitching behavior.

In the above embodiment, the hydraulic unit HU via the brake fluid BF is exemplified as the actuator that adjusts the braking torque Tq (result, braking force Fx) of the wheel WH. Alternatively, an electric actuator driven by an electric motor may be employed. In the electric actuator, the rotational power of the electric motor is converted into linear power, thereby pressing the friction member against the rotating member KT. Therefore, braking torque Tq is directly applied by the electric motor to generate braking force Fx, regardless of braking fluid pressure Pw. Furthermore, it may be a composite type in which a hydraulic actuator via brake fluid BF is used for the front wheels WHf, and an electric actuator is used for the rear wheels WHr. No matter which actuator is adopted, in the rear wheel floating suppression control, the front wheel braking force Fxf is reduced based on the compensation deceleration Gh.

GH...Deceleration calculation device, XA...Acquisition unit, XB...Calculation unit, XH...Compensation unit, XT...Delay unit, SC...Brake control device, BP...Brake operation member, CM...Master cylinder, CW...Wheel cylinder, HU ...Fluid unit, MT...Electric motor, HP...Fluid pump, VI...Inlet valve, VO...Outlet valve, UA...Pressure regulating valve, ECU...Controller, VW...Wheel speed sensor, GX...Deceleration sensor, Vw...Wheel speed, Vx...Vehicle speed, Gx...Detected deceleration, Ge...Calculated deceleration, Gh...Compensated deceleration, gh...Reference deceleration, dGx...Detected slope (amount of time change in detected deceleration Gx), dGe...Calculated slope (calculated) (amount of change over time in deceleration Ge), dgx...first gradient (predetermined value), dge...second gradient (predetermined value), ty...prohibition time (predetermined value), Hx...monitoring deviation, Tk...monitoring time, hx... Reference amount (predetermined initial value), tx...Reference time (predetermined initial value), Fx...braking force.

Claims (3)

A vehicle deceleration calculation device that compensates for zero point drift of detected deceleration detected by a deceleration sensor provided on a vehicle body,
a calculation unit that calculates a deceleration of the vehicle as a calculated deceleration based on a wheel speed that is a rotational speed of a wheel of the vehicle;
a compensation unit that compensates for the zero point drift based on a match between a detected slope that is the amount of time change in the detected deceleration and a calculated slope that is the amount of time change in the calculated deceleration;
The compensation section is
The method is configured to include a delay unit that delays the determination of coincidence when at least one of the following is satisfied: the detected slope is a first slope or more, and the calculated slope is a second slope or more. A vehicle deceleration calculation device. The vehicle deceleration calculation device according to claim 1,
The delay unit is a vehicle deceleration calculation device that prohibits the matching determination for a prohibited time. The vehicle deceleration calculation device according to claim 1,
The compensation section is
The coincidence is determined based on the fact that the deviation between the detected slope, which is the amount of time change in the detected deceleration, and the calculated slope, which is the amount of time change in the calculated deceleration, continues to be less than the monitoring deviation over the monitoring time. make a judgment,
The delay section is
A vehicle deceleration calculation device that executes at least one of a modification that reduces the monitoring deviation and a modification that increases the monitoring time.