JP6816406B2 - Vehicle braking control device - Google Patents

Description

The present invention relates to a vehicle braking control device.

Patent Document 1 states that, for the purpose of "improving the operation responsiveness by increasing the number of rotations when necessary without increasing the size of the electric motor of the actuator of the BBW type braking device", "to an electric signal. Based on this, in the BBW type braking device that operates the motor cylinders 19F and 19R using the electric motor 22 as the drive source to brake the wheels, the electric motor 22 is weakened and field controlled to increase the rotation speed at the initial stage of operation of the motor cylinders 19F and 19R. Therefore, the time lag from the output of the electric signal for operating the motor cylinders 19F and 19R to the actual generation of the braking force can be reduced to improve the operation responsiveness. And after the braking force is actually generated, Since the field weakening control can be released and the required braking force can be secured with sufficient torque, it is not necessary to use the electric motor 22 having a particularly large physique, and the electric motor 22 can be downsized and the operation responsiveness can be improved. Can be compatible with each other. "

Further, Patent Document 1 states that "the area A until the brake pads 35 and 35 come into contact with the brake disc 34 and the area B after the brake pads 35 and 35 come into contact with the brake disc 34 control the electric motor 22. Areas A and B are determined according to the pad clearance α. In the area A, even if the stroke of the piston 37 of the wheel cylinders 15 and 16 increases, the reaction force is generated because the pad clearance α exists. This is a region where the pad clearance α hardly increases, and the region B is a region where the reaction force sharply increases as the stroke of the piston 37 increases because the pad clearance α has already disappeared. The pad clearance α of the wheel cylinders 15 and 16 increases. In the existing region A, the current command value Id * in the d-axis direction of the electric motor 22 is increased in the negative direction, and so-called field weakening control is performed to increase the rotation speed of the electric motor 22, and the wheel cylinders 15 and 16 In the region B where the pad clearance α of the piston 37 disappears, the current command value Id * in the d-axis direction of the electric motor 22 is set to 0 or almost 0 to increase the torque of the electric motor 22. "

In Patent Document 2, for the purpose of "improving the responsiveness of braking force generation without increasing the size of the electric motor that drives the electric braking force generating means", "the target brake hydraulic pressure calculating means M1 is a slave cylinder. The target brake hydraulic pressure to be generated is calculated, the differential means M2 time-differentiates the target brake hydraulic pressure to calculate the rate of change of the target brake hydraulic pressure, and the field current calculation means M3 is the rate of change of the target brake hydraulic pressure. Based on this, the field current command value of the electric motor that drives the slave cylinder is calculated, and the electric motor control means M4 weakens the electric motor based on the field current command value to perform field control. When the rate of change of the target brake hydraulic pressure is large. Is an emergency in which the braking force needs to be increased rapidly. At this time, the field current command value is increased to weaken the field amount of the electric motor, thereby increasing the rotation speed of the electric motor. The slave cylinder can be operated quickly to improve the responsiveness of braking force generation. "

Further, Patent Document 2 states, "The electric motor 52 is driven to detect the caliper hydraulic pressure for each rotation position, and the rotation position Ang1 of the electric motor 52 when a predetermined caliper hydraulic pressure P is obtained is stored. The field current command value Id * increases in the negative direction as the rotation positions Ang1, Ang2, and Ang3 of the electric motor 52 increase, that is, as the forward positions of the pistons 38A and 38B increase, and weakens accordingly. The field amount increases and the rotation speed of the electric motor 52 increases. "

Patent Documents 1 and 2 describe "weakening field control (also referred to as weakening magnetic flux control)" by passing a negative current through the d-axis of an electric motor. In order for the weakening magnetic flux control to be performed more effectively, not only the pad clearance (also called the brake gap) but also the rigidity (spring constant) characteristics of the brake caliper (simply also called the caliper) CP and the like are immediately affected. You will need what you have done.

This will be described with reference to FIG. FIG. 6 is a characteristic diagram showing the relationship of the pressing force Fpa (reaction force from the caliper CP, friction member MS, etc.) with respect to the rotation angle Mka of the electric motor MTR, and the relationship of "force" with respect to "displacement" in the caliper CP. It represents "rigidity (spring constant)". The characteristic P1 indicates that the friction member MS is new, and the characteristic P2 indicates that the friction member MS is worn. With respect to the increase in the rotation angle Mka, the pressing force Fpa monotonically increases due to the non-linear characteristic of "convex downward".

In this non-linear characteristic, in the region Ra where the pressing force Fpa is from "0" to the value fpb, the change in the pressing force Fpa is slight even if the rotation angle Mka changes. In the region Ra, the gap between the friction member MS and the rotating member KT is first closed, and then the minute irregularities on the surface of the friction member MS are compressed. In the region Rb, the rigidity of the friction member MS and the rigidity of the caliper CP both affect. In the region Rb, the friction member MS and the caliper CP act as a series spring. Further, when the rotation angle Mka increases, the friction member MS is completely crushed and is not compressed any more. In the region Rc, the rigidity of the caliper CP is dominant, and the rigidity of the friction member MS has almost no effect.

Further, when the characteristic P1 and the characteristic P2 are compared, there is almost no difference in the region Ra, but in the region Rb, the characteristic P2 is more rigid (relative to the rotation angle Mka) than the characteristic P1 because the friction member MS becomes thinner. (Inclination of pressing force Fpa) becomes high. However, in the region Rc, since the rigidity of the caliper CP is dominant, the inclination of the pressing force Fpa with respect to the rotation angle Mka is substantially the same.

As described above, in the region where the pressing force Fpa is relatively small (regions Ra and Rb), it is necessary to change the rotation angle Mka in order for the pressing force Fpa to increase. That is, in order for the pressing force Fpa to increase rapidly, the rotation speed dMk becomes important. On the other hand, in the region where the pressing force Fpa is relatively large (region Rc), the pressing force Fpa changes significantly even if the rotation angle Mka changes slightly. That is, in the region Rc, the rotation speed dMk is not so important in the rapid increase of the pressing force Fpa. Therefore, it is desirable that the weakening magnetic flux control of the electric motor MTR is performed in consideration of such characteristics in the caliper CP.

JP-A-2007-245823 Japanese Unexamined Patent Publication No. 2008-184057

An object of the present invention is to provide a braking control device for a vehicle using a three-phase brushless motor, in which weakening magnetic flux control can be performed more effectively.

The vehicle braking control device according to the present invention drives an electric motor (MTR) based on a target pressing force (Fpt) corresponding to a required braking force on the wheels (WH) of the vehicle and is fixed to the wheels (WH). A friction member (MS) is pressed against the rotating member (KT) to generate a braking force on the wheel (WH). The vehicle braking control device includes a controller (ECU) that controls the electric motor (MTR) and a push that detects a push pressure (Fpa) that is a force that pushes the friction member (MS) against the rotating member (KT). It includes a pressure sensor (FPA).

In the brake control apparatus for a vehicle according to the present invention, the con preparative roller (ECU) is on the basis of the target pressing force (Fpt) calculates the command current (Ims) of the electric motor (MTR), the pressing force ( The indicated current (Ims) is adjusted based on Fpa) to calculate the target current (Imt), and the electric motor (MTR) is controlled based on the target current (Imt) . Before SL Con preparative roller (ECU), the more the pressing force (Fpa) is large, and calculates the target current (Imt) to decrease the d-axis component (Ids) of the command current (Ims). Further, the configuration preparative roller (ECU), the more the pressing force (Fpa) is large, q-axis component (Iqs, Iqr) of the command current (Ims) increased by the computing the target current (Imt).

The vehicle braking control device according to the present invention drives an electric motor (MTR) based on a target pressing force (Fpt) corresponding to a required braking force on the wheels (WH) of the vehicle and is fixed to the wheels (WH). A friction member (MS) is pressed against the rotating member (KT) to generate a braking force on the wheel (WH). The vehicle braking control device includes a controller (ECU) that controls the electric motor (MTR) and a rotation angle sensor (MKA) that detects the rotation angle (Mka) of the electric motor (MTR).

In the brake control apparatus for a vehicle according to the present invention, the con preparative roller (ECU) is on the basis of the target pressing force (Fpt) calculates the command current (Ims) of the electric motor (MTR), the rotation angle ( The indicated current (Ims) is adjusted based on Mka) to calculate the target current (Imt), and the electric motor (MTR) is controlled based on the target current (Imt) . Before SL Con preparative roller (ECU), the more the rotation angle (Mka) is large, and calculates a reduction to the target current (Imt) of the d-axis component (Ids) of the command current (Ims). Further, the configuration preparative roller (ECU), the more the rotation angle (Mka) is large, q-axis component (Iqs, Iqr) of the command current (Ims) increased by the computing the target current (Imt).

There is a trade-off relationship between the d-axis current and the q-axis current that can energize the electric motor MTR. In the region where the pressing force Fpa (rotation angle Mka) is relatively small in the rigidity characteristics of the caliper CP or the like, the electric motor MTR needs to rotate by a considerable amount in order to increase the pressing force Fpa. On the other hand, in the region where the pressing force Fpa (rotation angle Mka) is relatively large, the pressing force Fpa is greatly increased even if the rotation angle Mka is slightly increased.

According to the above configuration, when the pressing force Fpa (rotation angle Mka) is small, the d-axis indicated current Ids is increased and adjusted so that the d-axis current has priority over the q-axis current, and the q-axis indicated current. At least one of the Iqs reduction adjustments is applied to determine the target current Imt. On the other hand, when the pressing force Fpa (rotation angle Mka) is large, the q-axis current has priority over the d-axis current. Therefore, at least one of the decrease adjustment of the d-axis indicated current Ids and the increase adjustment of the q-axis indicated current Iqs is applied to determine the target current Imt. Therefore, it is possible to achieve control of the electric motor MTR with high response and power saving in accordance with the characteristics of the caliper CP and the like.

It is an overall block diagram of the vehicle which carries the braking control device BCS of the vehicle which concerns on this invention. It is a functional block diagram for demonstrating the processing in a controller ECU. It is a functional block diagram for demonstrating the processing in a switching control block SWT. It is an electric circuit diagram for demonstrating the three-phase brushless motor MTR and its drive circuit DRV. It is a functional block diagram for demonstrating the processing in the target current calculation block IMT. It is a characteristic figure for demonstrating the rigidity characteristic (that is, the relationship of the pressing force Fpa with respect to the rotation angle Mka) of a brake caliper CP and a friction member MS.

<Overall configuration of vehicle braking control device according to the present invention>
The braking control device BCS according to the present invention will be described with reference to the overall configuration diagram of FIG. In the following description, the components, arithmetic processing, signals, characteristics, and values with the same symbols perform the same functions. Therefore, duplicate description may be omitted.

For vehicles equipped with the braking control device BCS, the braking operation member BP, braking operation amount sensor BPA, controller ECU, master cylinder MC, stroke simulator SSM, simulator shutoff valve VSM, pressurizing unit KAU, switching valve VKR, master cylinder piping HMC , Wheel cylinder piping HWC, and pressure cylinder piping HKC are provided. Further, each wheel WH of the vehicle is provided with a brake caliper CP, a wheel cylinder WC, a rotating member KT, and a friction member MS.

The braking operation member (for example, the brake pedal) BP is a member operated by the driver to decelerate the vehicle. By operating the braking operation member BP, the braking torque of the wheel WH is adjusted, and a braking force is generated on the wheel WH. Specifically, a rotating member (for example, a brake disc) KT is fixed to the wheel WH of the vehicle. The brake caliper CP is arranged so as to sandwich the rotating member KT. A wheel cylinder WC is provided on the brake caliper (simply also referred to as caliper) CP. By adjusting (increasing or decreasing) the hydraulic pressure in the wheel cylinder WC of the caliper CP, the piston in the wheel cylinder WC is moved (advanced or retracted) with respect to the rotating member KT. By the movement of the piston, the friction member (for example, the brake pad) MS is pressed against the rotating member KT, and a pressing force is generated. The rotating member KT and the wheel WH are fixed via a fixed shaft DS. Therefore, a braking torque (braking force) is generated in the wheel WH by the frictional force generated by the pressing force. Therefore, the braking force required for the wheel WH (required braking force) is achieved according to the target value of the pressing force.

When the braking operation member BP is not operated, there is a slight gap (“brake gap”) between the friction member MS and the rotating member KT due to the elasticity of the cup seal in the wheel cylinder WC, the rotational runout of the rotating member KT, and the like. It is maintained with (called). Therefore, in the initial stage when the braking operation member BP is operated, first, the flow rate of the braking fluid is required by the amount of closing the brake gap. Since the brake gap is generated by the elasticity of the cup seal or the like, the hydraulic pressure of the braking fluid required to fill the gap is extremely low. Further, after the friction member MS comes into contact with the rotating member KT, a flow rate of the braking liquid is required to make the surface unevenness of the friction member MS uniform (that is, to slightly compress and deform). Similarly, the hydraulic pressure required for compressive deformation is low.

The braking operation amount sensor (simply also referred to as an operation amount sensor) BPA is provided on the braking operation member BP. The operation amount sensor BPA detects the operation amount Bpa of the braking operation member BP by the driver. Specifically, as the operation amount sensor BPA, a hydraulic pressure sensor that detects the pressure of the master cylinder MC, an operation displacement sensor that detects the operation displacement of the braking operation member BP, and an operation that detects the operation force of the braking operation member BP. At least one of the force sensors is employed. That is, the operation amount sensor BPA is a general term for the master cylinder hydraulic pressure sensor, the operation displacement sensor, and the operation force sensor. Therefore, the braking operation amount Bpa is determined based on at least one of the hydraulic pressure of the master cylinder MC, the operating displacement of the braking operation member BP, and the operating force of the braking operation member BP. The operation amount Bpa is input to the controller ECU.

The controller (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 in the microprocessor. The controller ECU controls the pressurizing unit KAU, the shutoff valve VSM, and the switching valve VKR based on the braking operation amount Bpa. Specifically, a signal (Sux or the like) for controlling the electric motor MTR, the shutoff valve VSM, and the switching valve VKR is calculated based on the programmed control algorithm and output from the controller ECU.

The controller ECU outputs a drive signal Vsm for opening the shutoff valve VSM when the operation amount Bpa becomes a predetermined value bp0 or more, and the switching valve VKR connects the pressurizing cylinder pipe HKC and the wheel cylinder pipe HWC. The drive signal Vkr for making the communication state is output to each solenoid valve VSM and VKR. In this case, the master cylinder MC is in a state of communicating with the simulator SSM, and the pressure cylinder KCL is in a state of communicating with the wheel cylinder WC.

The controller ECU calculates a drive signal (Sux, etc.) for driving the electric motor MTR based on the operation amount Bpa, the rotation angle Mka, and the pressing force Fpa (for example, the hydraulic pressure of the pressurizing cylinder KCL). Output to the drive circuit DRV. Here, the braking operation amount Bpa is detected by the braking operation amount sensor BPA, the actual rotation angle Mka is detected by the rotation angle sensor MKA, and the actual pressing pressure Fpa is detected by the pressing pressure sensor FPA. The pressure of the braking fluid in the wheel cylinder WC is controlled (maintained, increased, or decreased) by the pressurizing unit KAU driven by the electric motor MTR.

The master cylinder MC is mechanically connected to the braking operation member BP via the brake rod BRD. The master cylinder MC converts the operating force (brake pedal pedaling force) of the braking operating member BP into the pressure of the braking fluid. When the master cylinder pipe HMC is connected to the master cylinder MC and the braking operation member BP is operated, the braking fluid is discharged (pumped) from the master cylinder MC to the master cylinder pipe HMC. The master cylinder pipe HMC is a fluid path connecting the master cylinder MC and the switching valve VKR.

A stroke simulator (simply also referred to as a simulator) SSM is provided to generate an operating force on the braking operating member BP. A simulator shutoff valve (simply also referred to as a shutoff valve) VSM is provided between the hydraulic chamber in the master cylinder MC and the simulator SSM. The shutoff valve VSM is a two-position solenoid valve having an open position and a closed position. When the shutoff valve VSM is in the open position, the master cylinder MC and the simulator SSM are in a communication state, and when the shutoff valve VSM is in the closed position, the master cylinder MC and the simulator SSM are in a shutoff state (non-communication state). ). The shutoff valve VSM is controlled by a drive signal Vsm from the controller ECU. As the shutoff valve VSM, a normally closed solenoid valve (NC valve) can be adopted.

A piston and an elastic body (for example, a compression spring) are provided inside the simulator SSM. The braking fluid is moved from the master cylinder MC to the simulator SSM, and the piston is pushed by the inflowing braking fluid. A force is applied to the piston in a direction that prevents the inflow of the braking fluid by the elastic body. The elastic body forms an operating force (for example, a brake pedal pedaling force) when the braking operation member BP is operated.

≪Pressure unit KAU≫
The pressurizing unit KAU uses the electric motor MTR as a power source to discharge (pressure feed) the braking fluid to the pressurizing cylinder pipe HKC. Then, by this pressure, the pressurizing unit KAU presses (presses) the friction member MS against the rotating member KT to apply braking torque (braking force) to the wheel WH. In other words, the pressurizing unit KAU generates a force (pushing pressure) for pressing the friction member MS against the rotating member KT by the electric motor MTR.

The pressurizing unit KAU is composed of an electric motor MTR, a drive circuit DRV, a power transmission mechanism DDK, a pressurizing shaft KSF, a pressurizing cylinder KCL, a pressurizing piston PKC, and a pressing force sensor FPA.

The electric motor MTR is a power source for the pressurizing cylinder KCL to adjust the pressure of the braking fluid in the wheel cylinder WC (pressurization, depressurization, etc.). A three-phase brushless motor is adopted as the electric motor MTR. The electric motor MTR has three coils CLU, CLV, and CLW corresponding to the U phase, the V phase, and the W phase, respectively, and is driven by the drive circuit DRV. The electric motor MTR is provided with a rotation angle sensor MKA that detects the rotor position (rotation angle) Mka of the electric motor MTR. The rotation angle Mka is input to the controller ECU.

The drive circuit DRV is an electric circuit board on which a switching element (power semiconductor device) or the like for driving the electric motor MTR is mounted. Specifically, a three-phase bridge circuit is formed in the drive circuit DRV, and the energization state of the electric motor MTR is controlled based on the drive signal (Sux or the like). The drive circuit DRV is provided with a current sensor (for example, a current sensor) IMA that detects the actual current Ima (collective term for each phase) to the electric motor MTR. The current (detected value) Ima of each phase is input to the controller ECU.

The power transmission mechanism DDK decelerates the rotational power of the electric motor MTR, converts it into linear power, and outputs it to the pressurizing shaft KSF. Specifically, the power transmission mechanism DDK is provided with a speed reducer (not shown), and the rotational power from the electric motor MTR is reduced and output to a screw member (not shown). Then, the rotational power is converted into the linear power of the pressure shaft KSF by the screw member. That is, the power transmission mechanism DDK is a rotation / linear motion conversion mechanism.

A pressure piston PKC is fixed to the pressure shaft KSF. The pressurizing piston PKC is inserted into the inner hole of the pressurizing cylinder KCL to form a combination of the piston and the cylinder. Specifically, a seal member (not shown) is provided on the outer periphery of the pressure piston PKC to ensure liquidtightness with the inner hole (inner wall) of the pressure cylinder KCL. That is, a pressurizing chamber Rkc which is partitioned by the pressurizing cylinder KCL and the pressurizing piston PKC and filled with the braking fluid is formed.

The volume of the pressurizing chamber Rkc is changed by moving the pressurizing piston PKC in the central axis direction in the pressurizing cylinder KCL. Due to this volume change, the braking fluid is moved between the pressurizing cylinder KCL and the wheel cylinder WC via the braking pipes (fluid paths) HKC and HWC. By taking in and out the braking fluid from the pressurizing cylinder KCL, the hydraulic pressure in the wheel cylinder WC is adjusted, and as a result, the force (pressing pressure) for the friction member MS to press the rotating member KT is adjusted.

For example, as the pressing pressure sensor FPA, a hydraulic pressure sensor that detects the hydraulic pressure Fpa of the pressurizing chamber Rkc is built in the pressurizing unit KAU (particularly, the pressurizing cylinder KCL). The hydraulic pressure sensor (corresponding to the pressing pressure sensor) FPA is fixed to the pressurizing cylinder KCL and integrally configured as the pressurizing unit KAU. The detected value Fpa of the pressing force (that is, the hydraulic pressure of the pressurizing chamber Rkc) is input to the controller ECU. The pressurizing unit KAU has been described above.

The switching valve VKR switches between "a state in which the wheel cylinder WC is connected to the master cylinder MC" and "a state in which the wheel cylinder WC is connected to the pressure cylinder KCL". The switching valve VKR is controlled based on the drive signal Vkr from the controller ECU. Specifically, when the braking operation is not performed (in the case of "Bpa <bp0"), the wheel cylinder pipe HWC is communicated with the master cylinder pipe HMC via the switching valve VKR to pressurize. It is in a non-communication (blocking) state with the cylinder pipe HKC. Here, the wheel cylinder pipe HWC is a fluid path connected to the wheel cylinder WC. When the braking operation is performed (that is, when “Bpa ≧ bp0” is reached), the switching valve VKR is excited based on the drive signal Vkr, the communication between the wheel cylinder pipe HWC and the master cylinder pipe HMC is cut off, and the wheel The cylinder pipe HWC and the pressure cylinder pipe HKC are brought into communication with each other.

<Processing in controller ECU>
The processing in the controller (electronic control unit) ECU will be described with reference to the functional block diagram of FIG. As described above, the components, arithmetic processing, signals, characteristics, and values of the same symbol exert the same functions.

In the controller ECU, the electric motor MTR is driven and the solenoid valves VSM and VKR are excited based on the operation amount Bpa of the braking operation member BP. The drive circuit DRV (three-phase bridge circuit) is formed by the switching elements UX, SUZ, SVX, SVZ, SWX, and SWZ (also simply referred to as "SUP to SWZ"). The drive of the electric motor MTR is executed by the drive circuit DRV. Specifically, the controller ECU calculates signals Sux, Suz, Svx, Svz, Swx, Swz (also simply referred to as "Sux to Swz") for driving the switching elements SUX to SWZ. Further, the controller ECU determines the signals Vsm and Vkr for driving the solenoid valves VSM and VKR.

The controller ECU includes an instruction pressing force calculation block FPS, a wheel slip control block FSC, a pressing speed calculation block DFP, an instruction current calculation block IMS, a push pressure feedback control block FFB, a target current calculation block IMT, a switching control block SWT, and electromagnetic. It is composed of a valve control block SLC.

In the instruction pressing force calculation block FPS, the instruction pressing force Fps is calculated based on the braking operation amount Bpa and the calculation characteristic (calculation map) CFps. Here, the indicated pressing force Fps is a target value of the hydraulic pressure (corresponding to the pressing force) generated by the pressurizing unit KAU. Specifically, in the calculation characteristic CFps, the indicated pressing force Fps is calculated to be "0 (zero)" in the range from zero braking operation amount Bpa (corresponding to the case where braking operation is not performed) to less than the predetermined value bp0. When the manipulated variable Bpa is equal to or greater than the predetermined value bp0, the indicated pressing force Fps is calculated so as to monotonically increase from "0" as the manipulated variable Bpa increases. Here, the predetermined value bp0 is a value corresponding to the "play" of the braking operation member BP.

In the wheel slip control block FSC, the adjustment pressing force Fsc, which is a target value for wheel slip control, is calculated. Here, the "wheel slip control" improves the stability of the vehicle by independently and separately controlling the slip states of the four wheels WH of the vehicle. That is, the wheel slip control is at least one of anti-skid control (Antilock Brake Control), traction control (Traction Control), and vehicle stabilization control (Electronic Stability Control). Therefore, in the wheel slip control block FSC, the adjusted pressing force Fsc for executing at least one of anti-skid control, traction control, and vehicle stabilization control is calculated.

In the wheel slip control block FSC, the adjusting pressing force Fsc for anti-skid control is calculated. Specifically, based on the acquisition result (wheel speed Vwa) of the wheel speed sensor VWA provided on each wheel WH, the adjusted pressing force Fsc for executing the anti-skid control so as to prevent the wheel lock is calculated. For example, the wheel slip state amount Slp (control variable representing the deceleration slip state of the wheel) is calculated based on the wheel speed Vwa. Then, the adjusting pressing force Fsc is determined based on the wheel slip state amount Slp.

Similarly, in the wheel slip control block FSC, the adjusted pressing force Fsc is calculated in order to execute traction control so as to suppress wheel spin (over-rotation) based on the acquisition result (wheel speed Vwa) of the wheel speed sensor VWA. Wheel. Specifically, the adjusted pressing force Fsc is determined based on the wheel slip state amount Slp (control variable representing the state of wheel acceleration slip).

Further, in the wheel slip control block FSC, based on the acquisition results (steering angle Saa, yaw rate Yra, lateral acceleration Gya) of the steering angle sensor SAA and the vehicle behavior sensor (yaw rate sensor YRA, lateral acceleration sensor GYA), the vehicle The adjustment pressing force Fsc for executing the vehicle stabilization control is calculated so as to maintain the stability. Specifically, the adjustment pressing force Fsc is determined based on the steering angle Saa, the yaw rate Yra, the lateral acceleration Gya, and the vehicle speed Vxa so as to suppress at least one of the excessive understeering and oversteering of the vehicle. Will be done.

The indicated pressing force Fps from the indicated pressing force calculation block FPS and the adjusted pressing force Fsc from the wheel slip control block FSC are adjusted by the adjustment calculation (addition calculation), and the target pressing force Fpt is calculated. Here, the target pressing force Fpt is the final target value of the pressing force, and corresponds to the required braking force with respect to the wheel WH. Specifically, the adjustment pressing force Fsc is added from the indicated pressing force Fps to determine the target pressing force Fpt. For example, when anti-skid control is executed in the wheel slip control block FSC, the adjustment pressing force Fsc (negative value) that adjusts by reducing the indicated pressing force Fps is calculated so as to avoid the wheel lock. The wheel. Further, when the vehicle stabilization control for suppressing oversteering is executed by the wheel slip control block FSC, the indicated pressing force Fps is increased and adjusted so that the pressing force corresponding to the turning outer front wheel of the vehicle is increased. The adjustment pressing force Fsc (positive value) to be adjusted is determined.

In the pressing speed calculation block DFP, the pressing speed dFp is calculated based on the target pressing force Fpt corresponding to the required braking force for the wheel WH. Specifically, the target pressing force Fpt is time-differentiated to determine the pressing speed dFp. Therefore, the pressing speed dFp is the amount of change of the pressing pressure target value Fpt with respect to time.

In the indicated current calculation block IMS, the indicated current Ims of the electric motor MTR is based on the target pressing force Fpt, the pressing speed (time change amount of the target value) dFp, and the preset calculation characteristics (calculation map) CIqs and CIds. Is calculated. Here, the indicated current Ims is a target value (vector on the dq axis) of the current for controlling the electric motor MTR. The indicated current Ims is formed by a d-axis component (also referred to as “d-axis indicated current”) Ids and a q-axis component (also referred to as “q-axis indicated current”) Iqs. That is, the indicated current Ims is calculated as a vector on the dq axis, which is the rotor fixed coordinate system of the electric motor MTR. The indicated current Ims is also expressed as an indicated current vector (Ids, Iqs). The "d-axis" is the direction of the magnetic flux created by the magnetic poles of the magnet (that is, the direction of the magnetic field), and the "q-axis" is the axis that is magnetically orthogonal to the d-axis (that is, the torque generation direction). ..

The motor induction voltage is increased as the rotation speed dMk increases. Therefore, by passing a negative d-axis current after voltage saturation, the demagnetization effect due to the armature reaction is utilized, and the magnetic flux in the d-axis direction is reduced. Equivalent field weakening control (ie, weakening magnetic flux control) is realized.

The calculation characteristic CIqs is a characteristic for calculating the q-axis component (q-axis indicated current) Iqs of the indicated current Ims, and particularly corresponds to the case where the target pressing force Fpt increases. Specifically, in the calculation characteristic CIqs, the q-axis indicated current Iqs is determined so that the q-axis indicated current Iqs monotonically increases from “0” as the target pressing force Fpt increases from “0”.

The calculation characteristic CIds is a characteristic for calculating the d-axis component (d-axis indicated current) Ids of the indicated current Ims. The calculation characteristic CIds particularly corresponds to the case where the target pressing speed dFp increases. Specifically, in the calculation characteristic CIds, the d-axis indicated current Ids is determined to be "0" from the pressing speed dFp of "0" to the predetermined value dfo. Then, as the pressing speed dFp increases from the predetermined value dfo, the d-axis indicated current Ids is determined so that the d-axis indicated current Ids monotonically decreases from "0". That is, the d-axis indicated current Ids is determined as a negative value so as to weaken the magnetic flux. The weakening magnetic flux control is required when the rotation speed dMk is large. Therefore, in the case of "dFp ≦ dfo", "Ids = 0 (that is, the weak magnetic flux control is not executed)" is set.

In the pressing force feedback control block FFB, the target value of pressing force (for example, target hydraulic pressure) Fpt and the actual value of pressing force (hydraulic pressure detection value) Fpa are set as control state variables, and the electric motor is based on these. The compensation current Ifp of the MTR is calculated. Since an error occurs in the pressing force only by the control based on the indicated current Ims, the pressing force feedback control block FFB compensates for this error. The pressing force feedback control block FFB is composed of a comparison calculation and a compensation current calculation block IFP.

By the comparison calculation, the target value Fpt of the pressing force (corresponding to the required braking force of the wheel WH) and the actual value Fpa (corresponding to the actually generated braking force) are compared. Here, the actual pressing force Fpa is a detection value detected by the pressing force sensor FPA (for example, a hydraulic pressure sensor that detects the hydraulic pressure of the pressurizing cylinder KCL). In the comparison calculation, the deviation (pressing pressure deviation) eFp between the target pressing force (target value) Fpt and the actual pressing force (detected value) Fpa is calculated. The pressing force deviation eFp is input to the compensating current calculation block IFP as a control variable.

The compensation current calculation block IFP includes a proportional element block, a differential element block, and an integral element block. In the proportional element block, the proportional gain Kp is multiplied by the pressing pressure deviation eFp to calculate the proportional element of the pressing pressure deviation eFp. In the differential element block, the pressing force deviation eFp is differentiated, multiplied by the differential gain Kd, and the differential element of the pressing force deviation eFp is calculated. In the integration element block, the pressing force deviation eFp is integrated, and the integration gain Ki is multiplied by this to calculate the integrating element of the pressing force deviation eFp. Then, the compensation current Ifp is calculated by adding the proportional element, the differential element, and the integral element. That is, in the compensation current calculation block IFP, the actual pressing pressure (detected value) Fpa becomes the target pressing pressure (target value) Fpt based on the comparison result (pressing pressure deviation eFp) between the indicated pressing pressure Fps and the actual pressing pressure Fpa. So-called push pressure-based PID control is performed so that they match (ie, the deviation eFp approaches "0 (zero)").

In the target current calculation block IMT, the target current (target current vector), which is the final target value of the current, is based on the indicated current (instructed current vector) Ims and the compensation current (compensation value by pressing pressure feedback control) Ifp. Imt is calculated. The target current Imt is a vector on the dq axis, and is formed by a d-axis component (also referred to as “d-axis target current”) Idt and a q-axis component (also referred to as “q-axis target current”) Iqt. Specifically, the indicated current vector Ims is adjusted by a process described later to determine the target current Imt. Further, a compensation current Ifp is added to the indicated current Ims as a q-axis component, and the sum of these is calculated as the target current Imt. The target current Imt is also expressed as a target current vector (Idt, Iqt).

In the target current calculation block IMT, the sign (positive or negative of the value) of the target current Imt is determined based on the direction in which the electric motor MTR should rotate (that is, the direction in which the pressing force is increased or decreased). Further, the magnitude of the target current Imt is calculated based on the rotational power to be output of the electric motor MTR (that is, the amount of increase / decrease in pressing force). Specifically, when the braking pressure is increased, the sign of the target current Imt is calculated as a positive sign (Imt> 0), and the electric motor MTR is driven in the forward rotation direction. On the other hand, when the braking pressure is reduced, the sign of the target current Imt is determined to be a negative sign (Imt <0), and the electric motor MTR is driven in the reverse direction. Further, the larger the absolute value of the target current Imt is, the larger the output torque (rotational power) of the electric motor MTR is controlled, and the smaller the absolute value of the target current Imt is, the smaller the output torque is controlled.

In the switching control block SWT, drive signals Sux to Swz for performing pulse width modulation for each switching element SUX to SWZ are calculated based on the target current Imt (Idt, Iqt). Based on the target current Imt and the rotation angle Mka, the target value Emt of each of the U-phase, V-phase, and W-phase voltages (general term for the target voltages Eut, Evt, and Ewt of each phase) is calculated. Based on the target voltage Emt of each phase, the duty ratio Dtt of the pulse width of each phase (a general term for the duty ratios Dut, Dvt, and Dwt of each phase) is determined. Here, the "duty ratio" is the ratio of the on-time to one cycle, and "100%" corresponds to full energization. Then, based on the duty ratio (target value) Dtt, whether each switching element UX to SWZ constituting the three-phase bridge circuit is turned on (energized state) or off state (non-energized state). The drive signals Lux to Swz are calculated. The drive signals Sux to Swz are output to the drive circuit DRV.

The energized or de-energized state of the six switching elements UX to SWZ is individually controlled by the six drive signals Sux to Swz. Here, as the duty ratio Dtt (general term for each phase) is larger, the energization time per unit time is lengthened in each switching element, and a larger current is passed through the coil. Therefore, the rotational power of the electric motor MTR is large.

In the drive circuit DRV, each phase is provided with a current sensor IMA (general term for the current sensors IUA, IVA, and IWA of each phase), and the actual current Ima (general term for the actual currents Iua, Iva, and Iwa of each phase) is detected. To. The detected value Ima (generic name) of each phase is input to the switching control block SWT. Then, so-called current feedback control is executed so that the detected value Ima of each phase matches the target value Imt. Specifically, in each phase, the duty ratio Dtt (general term for the duty ratios Dut, Dvt, and Dwt of each phase) is individually corrected (fine-tuned) based on the deviation between the actual current Ima and the target current Imt. Ru. Highly accurate motor control can be achieved by this current feedback control.

The solenoid valve control block SLC calculates drive signals Vsm and Vkr for controlling the solenoid valves VSM and VKR based on the operation amount Bpa. When the operation amount Bpa is less than the predetermined amount bp0 (particularly, when "Bpa = 0"), the drive signal Vsm is determined so that the simulator shutoff valve VSM is in the open position corresponding to the non-braking operation (in particular, when "Bpa = 0"). For example, when the shutoff valve VSM is an NC valve, the drive signal Vsm indicates non-excitation). At the same time, in the case of "Bpa <bp0", "a state in which the master cylinder MC and the wheel cylinder WC are communicated with each other and the pressure cylinder KCL and the wheel cylinder WC are cut off (referred to as a non-excited state)". The drive signal Vkr is calculated.

After the operation amount Bpa is increased and the operation amount Bpa becomes a predetermined amount bp0 or more, it corresponds to the braking operation, and at that time (the braking operation start time), the shutoff valve VSM changes from the closed position to the open position. The drive signal Vsm is determined so as to be performed. When the shutoff valve VSM is an NC valve, an excitation instruction is started as a drive signal Vsm at the start of the braking operation. Further, at the start of the braking operation, the drive signal Vkr is set so that the master cylinder MC and the wheel cylinder WC are cut off and the pressure cylinder KCL and the wheel cylinder WC are communicated with each other (referred to as an excitation state). It is determined.

<Processing with switching control block SWT>
The processing in the switching control block SWT will be described with reference to the functional block diagram of FIG. In the switching control block SWT, the drive signals Sux to Swz of the six switching elements UX to SWZ constituting the three-phase bridge circuit BRG are determined based on the target current Imt, the actual current Ima, and the rotation angle Mka. The switching control block SWT is composed of a first conversion calculation block IHA, a target voltage calculation block EDQ, a second conversion calculation block EMT, a target duty calculation block DTT, and a drive signal calculation block SDR. The electric motor MTR is driven by so-called vector control.

In the first conversion calculation block IHA, the conversion actual current Iha is calculated based on the actual current Ima and the rotation angle Mka. The converted real current Iha is a conversion of the real current Ima from three-phase to two-phase and further converted from fixed coordinates to rotating coordinates. The converted actual current Iha is a vector on the dq axis (rotor fixed coordinates), and has a d-axis component (also referred to as “d-axis real current”) Ida and a q-axis component (also referred to as “q-axis real current”) Iqa. Is formed.

First, in the first conversion calculation block IHA, the actual current Ima is converted from three phases to two phases. The real current Ima is a general term for each phase (U phase, V phase, W phase) of the bridge circuit BRG. Specifically, the U phase real current Iua, the V phase real current Iva, and the W phase real current Iwa. It is composed of. In order to handle three signals at the same time, calculation in a three-dimensional space is required. In order to facilitate the calculation, the fact that "Iua + Iva + Iwa = 0" is established in an ideal three-phase alternating current is utilized, and the three-phase real current Ima (Iua, Iva, Iwa) is changed to the two-phase real current Ina (Iα). , Iβ). The conversion from three-phase to two-phase is called "Clarke conversion, or αβ conversion".

The three-phase real currents (detected values) Iua, Iva, and Iwa are converted into two-phase real currents Iα and Iβ by Clark conversion. That is, the real currents Iua, Iva, and Iwa of symmetric three-phase alternating current (three-phase alternating current shifted by 120 degrees) are converted into the equivalent two-phase alternating currents Iα and Iβ.

Further, in the first conversion calculation block IHA, coordinate conversion from fixed coordinates (stationary coordinates) to rotating coordinates is performed based on the rotation angle Mka, and the conversion actual current Iha is calculated. The converted real current Iha is formed by a d-axis component (d-axis real current) Ida and a q-axis component (q-axis real current) Iqa. That is, since the Clark-converted current value Ina is the current flowing through the rotor, the coordinates are transformed into the rotor fixed coordinates (rotating coordinates, dq-axis coordinates). Here, the transformation from fixed coordinates to rotating coordinates is called "Park transformation". Based on the rotor rotation angle Mka from the rotation angle sensor MKA, conversion from fixed coordinates to rotation coordinates (dq axis coordinates) is executed, and the actual current Iha (Ida, Iqa) after the coordinate conversion is determined.

In the target voltage calculation block EDQ, the target voltage vector Edq is calculated based on the target current vector Imt (Idt, Iqt) and the actual current Iha (Ida, Iqa) after the park conversion. In vector control, so-called current feedback control is executed so that the "d-axis and q-axis components Idt and Iqt of the target current" match the "d-axis and q-axis components Ida and Iqa of the actual current". Therefore, in the target voltage calculation block EDQ, PI control is performed based on the deviations (current deviations) of "d-axis, q-axis target currents Idt, Iqt" and "d-axis, q-axis actual currents Ida, Iqa". Will be In PI control, P control (proportional control, which is controlled according to the deviation between the target value and the actual value) and I control (integral control, which is controlled according to the integrated value of the deviation). ) And are performed in parallel.

Specifically, in the target voltage calculation block EDQ, the target voltage Edq is such that the current deviation decreases (that is, the deviation approaches "0") based on the deviation between the target current Imt and the converted actual current Iha. Is determined. The target voltage Edq is a vector on the dq axis, and is composed of a d-axis component (also referred to as “d-axis target voltage”) Edt and a q-axis component (also referred to as “q-axis target voltage”) Eqt.

In the second conversion calculation block EMT, the final target voltage Emt is calculated based on the target voltage vector Edq and the rotation angle Mka. The target voltage Emt is a general term for each phase of the bridge circuit BRG, and is composed of a U-phase target voltage Eut, a V-phase target voltage Evt, and a W-phase target voltage Ewt.

First, in the second conversion calculation block EMT, the target voltage vector Edq is inversely converted from the rotating coordinates to the fixed coordinates based on the rotation angle Mka, and the two-phase target voltages Eα and Eβ are calculated. The transformation is referred to as an "inverse Park transformation". Then, the two-phase target voltages Eα and Eβ are inversely converted into the three-phase target voltages Emt (voltage target values Eut, Evt, Ewt of each phase) by the space vector conversion.

In the target duty calculation block DTT, the duty ratio (target value) Dtt of each phase is calculated based on the target voltage Emt of each phase. The duty ratio Dtt is a general term for each phase, and is composed of a U-phase duty ratio Dut, a V-phase duty ratio Dvt, and a W-phase duty ratio Dwt. Specifically, according to the calculation characteristic CDtt, the duty ratio Dtt is calculated to monotonically increase from "0" as the voltage target value Emt of each phase increases from "0".

In the drive signal calculation block SDR, the signals Sux to Swz for driving the switching elements SUX to SWZ constituting each phase of the bridge circuit BRG are determined based on the duty ratio Dtt. Based on the drive signals Lux to Swz, the switching elements UX to SWZ are switched on / off, and the electric motor MTR is driven.

<3-phase brushless motor MTR and its drive circuit DRV>
The three-phase brushless motor MTR and its drive circuit DRV will be described with reference to the electric circuit diagram of FIG. The three-phase brushless motor MTR has three coils (windings) of a U-phase coil CLU, a V-phase coil CLV, and a W-phase coil CLW. In the brushless motor MTR, a magnet is arranged on the rotor side and a winding circuit (coil) is arranged on the stator side, and commutation is performed by the drive circuit at a timing that matches the magnetic poles of the rotor. , Rotationally driven.

The electric motor MTR is provided with a rotation angle sensor MKA that detects the rotation angle (rotor position) Mka of the electric motor MTR. As the rotation angle sensor MKA, a Hall element type sensor is adopted. Further, as the rotation angle sensor MKA, a variable reluctance type resolver can be adopted. The rotation angle Mka is input to the switching control block SWT of the controller ECU.

The drive circuit DRV is composed of a three-phase bridge circuit (simply also referred to as a bridge circuit) BRG and a stabilization circuit LPF. The drive circuit DRV is an electric circuit that drives the electric motor MTR, and is controlled by a switching control block SWT.

The bridge circuit BRG is formed by six switching elements (power transistors) UX, SUZ, SVX, SVZ, SWX, and SWZ (also referred to as "SUP to SWZ"). The bridge circuit BRG is driven based on the drive signals Sux, Suz, Svx, Svz, Swx, Swz (also referred to as "Sux to Swz") of each phase from the switching control block SWT in the drive circuit DRV, and the electric motor MTR. The output of is adjusted.

In the switching control block SWT, an instruction value (target value) for performing pulse width modulation is calculated for each switching element based on the target current Imt. The duty ratio of the pulse width (ratio of on-time to one cycle) is determined based on the magnitude of the target current Imt and the preset characteristics (calculation map). At the same time, the rotation direction of the electric motor MTR is determined based on the sign (positive or negative) of the target current Imt. For example, the rotation direction of the electric motor MTR is set as a positive (plus) value in the forward rotation direction and a negative (minus) value in the reverse rotation direction. Since the final output voltage is determined by the input voltage (voltage of the storage battery BAT) and the duty ratio Dtt, the rotation direction and output torque of the electric motor MTR are determined.

Further, in the switching control block SWT, each switching element constituting the bridge circuit BRG is turned on (energized state) or turned off (non-energized state) based on the duty ratio (target value) Dtt. The drive signals Lux to Swz are calculated. These drive signals Sux to Swz control the energized or de-energized state of the switching elements SUX to SWZ. Specifically, the larger the duty ratio Dtt, the longer the energizing time per unit time in the switching element, the larger current flows through the electric motor MTR, and the larger the output (rotational power).

A storage battery BAT is connected to the input side of the 3-phase bridge circuit (also referred to as an inverter circuit) BRG via a stabilizing circuit LPF, and an electric motor MTR is connected to the output side of the bridge circuit BRG. In the bridge circuit BRG, three phases (U phase, V phase, W phase) are formed by using a voltage type bridge circuit having an upper and lower arm configuration in which switching elements are connected in series as one phase. The upper arms of the three phases are connected to the power line PWL connected to the anode side of the storage battery BAT. Further, the lower arms of the three phases are connected to the power line PWL connected to the cathode side of the storage battery BAT. In the bridge circuit BRG, the upper and lower arms of each phase are connected to the power line PWL in parallel with the storage battery BAT.

The six switching elements UX to SWZ are elements that can turn on or off a part of the electric circuit. For example, MOS-FETs and IGBTs are used as the switching elements UX to SWZ. In the brushless motor MTR, the switching elements UX to SWZ constituting the bridge circuit BRG are controlled based on the detected value Mka of the rotation angle (rotor position). Then, the current directions (that is, the exciting directions) of the coils CLU, CLV, and CLW of each of the three phases (U phase, V phase, and W phase) are sequentially switched, and the electric motor MTR is rotationally driven. That is, the rotation direction (forward rotation direction or reverse rotation direction) of the brushless motor MTR is determined by the relationship between the rotor and the exciting position. Here, the forward rotation direction of the electric motor MTR is the rotation direction corresponding to the increase in the hydraulic pressure (as a result, the pressing pressure) Fpa by the pressurizing unit KAU, and the reverse rotation direction of the electric motor MTR is the decrease in the hydraulic pressure Fpa. The direction of rotation corresponding to.

A current sensor IMA (generic name) for detecting the actual current Ima (generic name of each phase) between the bridge circuit BRG and the electric motor MTR is provided in each of the three phases (U phase, V phase, W phase). Specifically, the U-phase current sensor IUA that detects the U-phase real current Iua, the V-phase current sensor IVA that detects the V-phase real current Iva, and the W-phase current sensor IWA that detects the W-phase real current Iwa are Provided in each phase. The detected currents Iua, Iva, and Iwa of each phase are input to the switching control block SWT, respectively.

Then, in the switching control block SWT, the above-mentioned current feedback control is executed. The duty ratio Dtt is corrected (fine-tuned) based on the deviation between the actual current Ima and the target current Imt. By this current feedback control, the actual value Ima and the target value Imt are controlled to match (that is, the current deviation approaches "0"). As a result, highly accurate motor control can be achieved.

The drive circuit DRV receives power from a power source (storage battery BAT, generator ALT). In order to reduce fluctuations in the supplied power (voltage), the drive circuit DRV is provided with a stabilizing circuit LPF. The stabilizing circuit LPF is a so-called LC circuit composed of a combination of at least one capacitor (capacitor) and at least one inductor (coil).

<Processing with target current calculation block IMT>
The processing in the target current calculation block IMT will be described with reference to the functional block diagram of FIG. In the target current calculation block IMT, the target current Imt, which is the final current target, is determined in consideration of the rigidity characteristics of the caliper CP and the like. That is, in the target current calculation block IMT, the indicated current Ims is adjusted based on the pressing force detection value Fpa or the like, and the target current Imt is determined. The target current calculation block IMT is composed of a q-axis first coefficient calculation block KFQ, a return determination block HNM, a q-axis second coefficient KRQ block, a d-axis first coefficient calculation block KFD, and a d-axis second coefficient block KRD. Will be done.

First, the q-axis component (q-axis target current) Iqt of the target current Imt will be described. The compensation current Ifp is added to the q-axis indicated current Iqs, and the compensated indicated current Iqr is calculated. The compensation current Ifp is a target value of the compensation current in the pressing feedback control. The q-axis indicated current Iqr after compensation is adjusted based on at least one of the pressing force Fpa and the pressing speed dFp, and the q-axis target current Iqt is calculated.

In the q-axis first coefficient calculation block KFQ, the q-axis first coefficient Kfq is calculated based on the actual pressing force Fpa. The q-axis first coefficient Kfq is a coefficient for adjusting the indicated current Iqr after compensation, and is a value of “0” or more. The q-axis first coefficient Kfq is determined to increase as the pressing force Fpa increases, based on the calculation characteristic CKfq. Specifically, in the calculation characteristic CKfq, when the pressing force Fpa is "0" or more and less than the predetermined value fqa, the q-axis first coefficient Kfq is the predetermined value kqa ("0" or more and less than "1"". It is the value of, and is determined by the lower limit value). Then, when the pressing force Fpa is equal to or more than the predetermined value fqa and less than the predetermined value fqb, the q-axis first coefficient Kfq is determined to monotonically increase from the predetermined value kqa. Further, when the pressing force Fpa is equal to or higher than the predetermined value fqb, the q-axis first coefficient Kfq is limited to the predetermined value kqb (a value larger than the predetermined value kqa and an upper limit value). Here, the calculation characteristic CKfq is preset in consideration of the rigidity characteristics of the caliper CP / friction member MS. Therefore, the respective predetermined values fqa, fqb, kqa, and kqb are preset constants.

The q-axis first coefficient Kfq is multiplied by the indicated current Iqr after compensation, and the q-axis target current Iqt is calculated. That is, it is determined that the q-axis target current Iqt increases as the actual pressing force Fpa increases.

In the return determination block HNM, "whether or not the pressing force Fpa is reduced (that is, whether or not it is in the return state)" is determined. For example, the return determination is performed based on "whether or not the pressing speed dFp is less than" 0 "". Then, based on the determination result of the return determination block HNM, the q-axis second coefficient Krq is output from the q-axis second coefficient KRQ block. Like the q-axis first coefficient Kfq, the q-axis second coefficient Krq is a coefficient for adjusting the post-compensation indicated current Iqr, and is a value of “0” or more. The q-axis second coefficient Krq is multiplied by the indicated current Iqr after compensation, and the q-axis target current Iqt is calculated.

When the actual pressing force Fpa is increased or maintained constant and the judgment condition is denied by the return judgment block HNM (in the case of "NO"), the q-axis second coefficient KRQ block is used. "1" is output. Therefore, when the actual pressing force Fpa is increased or held, the adjustment by the q-axis second coefficient Krq is not performed.

When the actual pressing force Fpa is reduced and the judgment condition is affirmed in the return judgment block HNM (when "YES"), the q-axis second coefficient KRQ block is changed to the q-axis second coefficient Krq. As a result, the q-axis correction value kqm is output. The correction value kqm for the q-axis is a preset predetermined value, which is smaller than "1". For example, a value of "0.7 ± 30%" can be adopted as the q-axis correction value kdm. Therefore, when the actual pressing force Fpa is decreasing, the q-axis target current Iqt is adjusted to be smaller than when the pressing force Fpa is increased or held.

Next, the d-axis component (d-axis target current) Idt of the target current Imt will be described. The d-axis indicated current Ids is adjusted based on at least one of the pressing force Fpa and the pressing speed dFp, and the d-axis target current Idt is calculated.

In the d-axis first coefficient calculation block KFD, the d-axis first coefficient Kfd is calculated based on the actual pressing force Fpa. The d-axis first coefficient Kfd is a coefficient for adjusting the d-axis indicated current Ids, and is a value of “0” or more. The d-axis first coefficient Kfd is determined to decrease as the pressing force Fpa increases, based on the calculation characteristic CKfd. Specifically, in the calculation characteristic CKfd, when the pressing force Fpa is "0" or more and less than the predetermined value fda, the d-axis first coefficient Kfd is a predetermined value kda ("1" or more). Upper limit) is determined. Then, when the pressing force Fpa is equal to or greater than the predetermined value fda and less than the predetermined value fdb, the d-axis first coefficient Kfd is determined to monotonically decrease from the predetermined value kda. Further, when the pressing force Fpa is equal to or higher than the predetermined value fdb, the d-axis first coefficient Kfd is limited to the predetermined value kdb (“0” or more, smaller than the predetermined value kda, lower limit value). Will be done. Here, the calculation characteristic CKfd is preset in consideration of the rigidity characteristics of the caliper CP / friction member MS. Therefore, the respective predetermined values fda, fdb, kda, and kdb are preset constants.

As in the case of the q-axis indicated current Iqr, the d-axis first coefficient Kfd is multiplied by the d-axis indicated current Ids, and the d-axis target current Idt is calculated. That is, it is determined that the d-axis target current Idt decreases as the actual pressing force Fpa increases.

Similar to the q-axis second coefficient block KRQ, the d-axis second coefficient Krd is output from the d-axis second coefficient block KRD based on the determination result of the return determination block HNM. The d-axis second coefficient Krd is a coefficient for adjusting the d-axis indicated current Ids, like the d-axis first coefficient Kfd, and is a value of “0” or more. The d-axis second coefficient Krd is multiplied by the d-axis indicated current Ids, and the d-axis target current Idt is calculated.

When the actual pressing force Fpa is increased or maintained constant and the judgment condition is denied by the return judgment block HNM (in the case of "NO"), the d-axis second coefficient block KRD is used. "1" is output. Therefore, when the actual pressing force Fpa is increased or held, the adjustment by the d-axis second coefficient Krd is not performed.

When the actual pressing force Fpa is reduced (that is, in the return state) and the judgment condition is affirmed in the return judgment block HNM (when "YES"), the d-axis second coefficient block The d-axis correction value kdm is output from the KRD as the d-axis second coefficient Krd. The correction value kdm for the d-axis is a predetermined value set in advance and is smaller than "1". For example, a value of "0.5 ± 30%" can be adopted as the d-axis correction value kdm. Therefore, when the actual pressing force Fpa is decreased (in the returned state), the d-axis target current Idt is adjusted to be smaller than when the pressing force Fpa is increased or held. Will be done.

In the target current calculation block IMT, the target current Imt (Idt, Iqt) is determined in consideration of the characteristics of the rigidity (spring constant) of the caliper CP / friction member MS described with reference to FIG. That is, the indicated current Ims (Ids, Iqs) is adjusted by at least one of the d-axis first coefficient Kfd and the q-axis first coefficient Kfq, and the target current Imt (Idt, Iqt) is calculated. .. For example, as the actual pressing force Fpa is larger, the d-axis component (d-axis indicated current) Ids of the indicated current Ims is reduced, and the target current Imt (particularly, the d-axis target current Idt) is calculated. Further, as the pressing force Fpa is larger, the q-axis components (q-axis indicated current) Iqs and Iqr of the indicated current Ims are increased, and the target current Imt (particularly, the q-axis target current Iqt) is calculated.

In the regions Ra and Rb where the pressing force Fpa is relatively small, the electric motor MTR needs to rotate by a considerable amount in order to increase the pressing force Fpa. On the other hand, in the region Rc where the pressing force Fpa is relatively large, the pressing force Fpa is greatly increased only by slightly increasing the rotation angle Mka. There is a trade-off relationship between the d-axis current and the q-axis current that can energize the electric motor MTR. Therefore, when the pressing force Fpa is small, at least one of the adjustment for increasing the d-axis indicated current Ids and the adjustment for decreasing the q-axis indicated current Iqs so that the d-axis current has priority over the q-axis current. One is applied to determine the target current Imt. On the other hand, when the pressing force Fpa is large, the q-axis current has priority over the d-axis current. Therefore, at least one of the decrease adjustment of the d-axis indicated current Ids and the increase adjustment of the q-axis indicated current Iqs is applied to determine the target current Imt. By the adjustment, control of the electric motor MTR having high response and no waste can be achieved according to the characteristics of the caliper CP and the like.

In addition, in the above regions Ra, Rb, and Rc, the actual pressing force (detected value) Fpa is not easily affected by the wear of the friction member MS. That is, the rotation angle Mka changes significantly due to the wear of the friction member MS, but the pressing force Fpa does not change so much. Therefore, by adopting the pressing force Fpa in the adjustment of the target current Imt (that is, the calculation of the first coefficients Kfd and Kfq), the vector control of the robust electric motor MTR which is not affected by the wear of the friction member MS can be performed. Can be achieved.

In the target current calculation block IMT, the indicated current Ims (Ids, Iqs) is adjusted based on the determination of "whether or not the actual pressing force Fpa is decreasing", and the target current Imt (Idt, Iqt) is determined. Will be done. Specifically, at least one of the d-axis second coefficient Krd and the q-axis second coefficient Krq is determined based on the determination result, the indicated current Ims is corrected, and the target current Imt is calculated. .. This is because when the pressing force Fpa is increased or held, the electric motor MTR must generate a power in a direction opposite to the spring force due to the caliper CP or the like, but the pressing force Fpa is decreased. In some cases, the spring force acts as a force to assist the electric motor MTR. Therefore, when the pressing force Fpa decreases, the target current Imt is determined by adjusting so that the indicated current Ims becomes smaller than when the pressing force Fpa increases or is held. As a result, appropriate control of the electric motor MTR can be achieved according to the direction of the spring force of the caliper CP or the like.

In particular, when "the actual pressing force Fpa is large and the pressing force Fpa is reduced", the rotational speed dMk of the electric motor MTR changes at an accelerating rate due to the spring force of the caliper CP, the friction member MS, or the like. .. Therefore, in the case of "when the pressing force Fpa is large and in the returning state", the "pressing pressure" is determined by the d-axis first coefficient Kfd and the d-axis second coefficient Krd (that is, the d-axis correction value kdm). The d-axis target current Idt is adjusted to be extremely small as compared with the case where the Fpa is small or the pressing force Fpa is increased / maintained. As a result, the electric motor MTR can be efficiently energized.

<Other embodiments>
Hereinafter, other embodiments will be described. In other embodiments, the same effect as described above is obtained. That is, control of a highly responsive electric motor MTR according to the spring characteristics of the caliper CP or the like can be achieved, and appropriate control of the electric motor MTR can be achieved according to the direction of action of the spring force of the caliper CP or the like. ..

In the above embodiment, the configuration of the disc type braking device (disc brake) has been exemplified. In this case, the friction member MS is a brake pad, and the rotating member KT is a brake disc. A drum type braking device (drum brake) may be adopted instead of the disc type braking device. In the case of a drum brake, a brake drum is adopted instead of the caliper CP. The friction member MS is a brake shoe, and the rotating member KT is a brake drum.

In the above embodiment, a pressurizing unit KAU applies a braking force to one wheel WH. However, the pressurizing unit KAU may generate braking forces on the plurality of wheels WH. In this case, a plurality of wheel cylinders WC are connected to the fluid path HWC.

Further, as the pressurizing cylinder KCL, one having two hydraulic chambers partitioned by two pressurizing pistons can be adopted. That is, a tandem type configuration is adopted for the pressure cylinder KCL. Then, two wheel cylinders WC of the four wheel WH are connected to one hydraulic chamber, and the remaining two wheel cylinders WC of the four wheel WH are connected to the other hydraulic chamber. .. As a result, a so-called front-rear type or diagonal type fluid configuration can be formed using the pressure cylinder KCL as a hydraulic pressure source.

In the above embodiment, the configuration of a hydraulic braking control device in which the rotational power of the electric motor MTR is converted into the hydraulic pressure of the wheel cylinder WC via the braking fluid and the braking force is generated in the wheel WH is exemplified. It was. Instead of this, an electromechanical braking control device that does not use a braking fluid may be adopted. In this case, the KAU is mounted on the caliper CP. Further, as the pressing pressure sensor FPA, a thrust sensor is adopted instead of the hydraulic pressure sensor. For example, the thrust sensor may be provided between the power transmission mechanism DDK and the pressurizing piston PKC, as shown in “(FPA)” in FIG.

Further, a composite type configuration may be formed in which a hydraulic pressure unit via a braking fluid is adopted for the front wheels and an electromechanical pressure unit is adopted for the rear wheels.

In the above embodiment, the q-axis first coefficient Kfq and the q-axis second coefficient Krq are multiplied by the compensated indicated current Iqr (= Iqs + Ifp) to calculate the final q-axis target current Iqt. Instead, the q-axis first coefficient Kfq and the q-axis second coefficient Krq can be multiplied by the q-axis indicated current Iqs, and then the compensation current Ifp can be added. Even in this case, the q-axis indicated current Iqs is adjusted by the q-axis first coefficient Kfq as the actual pressing force Fpa increases, and the q-axis target current Iqt is determined to increase. Further, in the return state, the q-axis indicated current Iqs is adjusted by the q-axis second coefficient Krq, and the q-axis target current Iqt is determined to decrease.

In the above embodiment, the indicated current Ims is adjusted (increased or decreased) based on the pressing force Fpa. There is a predetermined relationship (see FIG. 6) between the rotation angle Mka and the pressing force Fpa. Although it is a little disadvantageous from the viewpoint of wear of the friction member MS, the indicated current Ims can be adjusted based on the rotation angle Mka instead of the pressing force Fpa. In this case, the rotation angle Mka is input to the d-axis and q-axis first coefficient calculation blocks KFD and KFQ instead of the pressing force Fpa. Further, the calculation characteristics CKfd and CKfq for the d-axis and q-axis first coefficients are set based on the rotation angle Mka instead of the pressing force Fpa (see FIG. 5 above). Then, according to the d-axis first coefficient Kfd, as the rotation angle Mka is larger, the d-axis component Ids of the indicated current Ims is reduced, and the target current Imt (particularly, the d-axis target current Idt) is calculated. Further, according to the q-axis first coefficient Kfq, as the rotation angle Mka is larger, the q-axis components Iqs and Iqr of the indicated current Ims are increased, and the target current Imt (particularly, the q-axis target current Iqt) is calculated.

BP: Braking operation member, MTR: Electric motor (3-phase brushless motor), KAU: Pressurizing unit, ECU: Controller, DRV: Drive circuit, BPA: Operation amount sensor, FPA: Push pressure sensor, MKA: Rotation angle sensor, IMA ... Current sensor.

Claims (4)

A vehicle braking control device that drives an electric motor based on a target pressing force according to a required braking force on the wheels of a vehicle and presses a friction member against a rotating member fixed to the wheels to generate a braking force on the wheels. And
The controller that controls the electric motor and
A pressing force sensor that detects the pressing force, which is the force with which the friction member is pressed against the rotating member,
With
The Con DOO roller,
The indicated current of the electric motor is calculated based on the target pressing force.
The target current is calculated by adjusting the indicated current based on the pressing force.
On the basis of the target current, and controlling said electric motor,
The controller
A vehicle braking control device that calculates the target current by reducing the d-axis component of the indicated current as the pressing force increases. A vehicle braking control device that drives an electric motor based on a target pressing force corresponding to a required braking force on the wheels of a vehicle and presses a friction member against a rotating member fixed to the wheels to generate a braking force on the wheels. And
The controller that controls the electric motor and
A pressing force sensor that detects the pressing force, which is the force with which the friction member is pressed against the rotating member,
With
The controller
The indicated current of the electric motor is calculated based on the target pressing force.
The target current is calculated by adjusting the indicated current based on the pressing force.
Control the electric motor based on the target current,
The controller
A vehicle braking control device that calculates the target current by increasing the q-axis component of the indicated current as the pressing force increases. A vehicle braking control device that drives an electric motor based on a target pressing force corresponding to a required braking force on the wheels of a vehicle and presses a friction member against a rotating member fixed to the wheels to generate a braking force on the wheels. And
The controller that controls the electric motor and
A rotation angle sensor that detects the rotation angle of the electric motor and
With
The controller
The indicated current of the electric motor is calculated based on the target pressing force.
The target current is calculated by adjusting the indicated current based on the rotation angle.
Control the electric motor based on the target current,
The controller
A vehicle braking control device that calculates the target current by reducing the d-axis component of the indicated current as the rotation angle is larger. A vehicle braking control device that drives an electric motor based on a target pressing force corresponding to a required braking force on the wheels of a vehicle and presses a friction member against a rotating member fixed to the wheels to generate a braking force on the wheels. And
The controller that controls the electric motor and
A rotation angle sensor that detects the rotation angle of the electric motor and
With
The controller
The indicated current of the electric motor is calculated based on the target pressing force.
The target current is calculated by adjusting the indicated current based on the rotation angle.
Control the electric motor based on the target current,
The controller
A vehicle braking control device that calculates the target current by increasing the q-axis component of the indicated current as the rotation angle is larger.