Electric brake device

Abstract

To provide an electric brake device that achieves both cost reduction and high arithmetic processing capacity.SOLUTION: An electric brake device includes an electric motor and a control device for controlling the electric motor. The control device includes a computing unit provided with: a first control arithmetic unit which determines motor coil electric conduction conditions for the electric motor so as to exhibit a desired driving force of the electric motor; and a second control arithmetic unit which determines a target driving force of the electric motor required for exhibiting the desired brake force at a prescribed period. The computation unit includes an operation priority setting unit, which sets a priority between the arithmetic units and suspends or does not allow start of an operation of the other arithmetic unit of lower priority from when an operation of the arithmetic unit of higher priority is executed to when it is completed. The period of the second control arithmetic unit is a period longer than the period of the first control arithmetic unit, and the priority of the first control arithmetic unit is set higher than the priority of the second control arithmetic unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electric brake device. [Background technology]

[0002] Conventionally, in the field of electric brake devices, a technology such as an electric actuator using a planetary roller screw structure has been proposed (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-194356 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an electric brake device such as that described in Patent Document 1, in which depression of the brake pedal converts the rotational motion of a motor into linear motion via a linear motion mechanism using a planetary roller screw structure to press a friction material such as a brake pad against a brake rotor such as a brake disc to generate a braking force, it is generally required to reduce the cost of a computing device such as a microcomputer that realizes the electric brake control device. On the other hand, the electric brake device may require high-speed and high-precision braking operation to perform vehicle control such as anti-lock control and attitude control, and therefore may also require high computing power.

[0005] The demand for cost reduction and high computing power are a trade-off when considering a system. If a computing device with high computing power is used, high costs may become an issue, while if a computing device with low computing power is used, costs will be reduced but braking performance may not be satisfactory, which may impair comfort, etc.

[0006] SUMMARY OF THE PRESENT EMBODIMENT In order to solve the above-mentioned problems, an object of the present invention is to provide an electric brake device which achieves both cost reduction and high computational processing capacity. [Means for solving the problem]

[0007] Generally speaking, the present invention is based on the principle that in each of the specified calculation units in the electric brake device, such as the control calculation unit and redundant calculation unit described below, the calculation period is different for each calculation (some have the same period), and priorities are set to deal with (manage, adjust, etc.) conflicts in the times (timings) at which the calculations are performed in the respective calculation units.

[0008] In order to achieve the above object, an electric brake device according to the present invention comprises: An electric brake device comprising: a brake rotor; friction material that comes into contact with the brake rotor to generate a braking force; an electric motor; friction material operation means that brings the friction material into contact with the brake rotor by a rotational force of the electric motor; and a control device that controls the electric motor to generate a desired braking force, The control device, a first control calculation unit that determines (or calculates) a motor coil current supply condition of the electric motor at a predetermined period so that the electric motor exerts a desired driving force; a second control calculation unit that determines (or calculates) a target driving force of the electric motor required to exert the desired braking force at a predetermined period; A computing unit provided with The computing device has an operation priority setting unit that sets a priority of each operation unit, and suspends or does not start an operation of another operation unit having a lower priority until the operation of the operation unit having a higher priority is executed and completed, the period of the second control calculation unit is longer than the period of the first control calculation unit, The priority of the first control calculation unit is set to be higher than the priority of the second control calculation unit.

[0009] In general, in order to generate a desired driving force of the electric motor, the response speed of a brake force control system (e.g., a control system that operates a motor torque to generate a desired brake force) that determines a target driving force of the electric motor required to generate a desired brake force is allowed to be designed to be relatively slower than the response speed of a motor control system (e.g., a control system that operates an applied voltage to achieve a desired motor current) that determines a motor coil current condition of the electric motor. Therefore, according to the above-mentioned configuration of the electric brake device according to the present invention, the load on the calculator can be reduced by making the period of the brake force control system such as the second control calculation unit longer than the period of the motor control system such as the first control calculation unit. At the same time, since the relatively high-speed motor control system is relatively more affected by delays due to calculation time, a more stable system can be configured by prioritizing the calculation of the motor control system when the calculations are executed at the same timing. In other words, even if a calculator with inferior calculation power is used, high calculation processing power can be exhibited without incurring costs, and the possibility of causing a hindrance to comfort and safety can be reduced. As described above, the electric brake device according to the present invention can achieve both cost reduction and high calculation processing power.

[0010] The computing unit includes: an electric brake device stiffness which is a correlation between a motor rotation amount of the electric motor and a braking force; a load conversion efficiency which is a correlation between the motor torque of the electric motor and the braking force; a motor temperature of the electric motor obtained based on a relationship between a voltage and a current of the electric motor or a motor temperature of the electric motor obtained based on a temperature sensor provided in the electric motor; a third control calculation unit that estimates at least one of the following at a predetermined period; The period of the third control calculation unit is longer than the period of the second control calculation unit, The third control calculation unit may have a lower priority than the second control calculation unit. The stiffness of the electric brake device, the load conversion efficiency, and the motor temperature may not change suddenly, and the estimation calculation of the third control calculation unit may have a slower estimation period than that of the brake force control system. Therefore, the load on the calculator can be reduced by slowing down the calculation period of the estimation calculation as described above. At the same time, a more stable system can be configured by prioritizing the calculation of the brake force control system, which is relatively fast. The third control calculation unit estimates characteristic values ​​such as motor characteristics and actuator characteristics including the stiffness, conversion efficiency, temperature, etc., and these can be appropriately used for controlling the electric brake. For example, by estimating a motor angle that can generate a predetermined brake force using the stiffness of the electric brake device, more accurate brake control is possible. For example, by estimating a reaction torque under a predetermined brake force condition using the load conversion efficiency, more accurate brake control is possible. For example, when the motor temperature approaches the heat resistance temperature of the motor, the function of the electric brake is restricted to lower the motor temperature, thereby reducing the risk of failure of the electric brake device.

[0011] The computing unit includes: a first redundancy calculation unit is provided which stores a predetermined allowable range or information related to the allowable range for a first factor which is either a voltage or a current of the electric motor or a relationship between the voltage and the current, and determines at a predetermined cycle that the electric brake device is abnormal based on the first factor being out of the allowable range; the period of the first redundant calculation unit is equal to or longer than the period of the first control calculation unit; The priority of the first redundant calculation unit may be set lower than the priority of the first control calculation unit. Also, the period of the first redundant calculation unit is shorter than the period of the second control calculation unit; The priority of the first redundant calculation unit may be set to be higher than the priority of the second control calculation unit. Since the first redundant calculation function unit mainly estimates abnormalities that may impair the function of the first control calculation function unit and processes abnormalities when they occur, the above-mentioned periodic and priority relationships make it possible to process abnormalities in the first redundant calculation function unit without compromising the effect of achieving both cost reduction and high calculation processing power as described above. The information regarding the allowable range refers to information, means, etc., that can derive the allowable range, including a calculation formula, a table (Look Up Table; LUT), etc.

[0012] The computing unit includes: a second redundancy calculation unit is provided which stores a predetermined allowable range or information relating to the allowable range for a second factor which is at least a relationship between a driving force of the electric motor and an amount of motor rotation, and determines at a predetermined period that the electric brake device is abnormal based on the second factor being out of the allowable range; the period of the second redundant calculation unit is equal to or longer than the period of the second control calculation unit; The priority of the second redundant calculation unit may be set lower than the priority of the second control calculation unit. Also, the period of the second redundant calculation unit is shorter than the period of the third control calculation unit; The second redundant calculation unit may have a higher priority than the third control calculation unit. Since the second redundant calculation function unit mainly estimates abnormalities that may impair the function of the second control calculation function unit and processes abnormalities when they occur, the above-mentioned periodic and priority relationships make it possible to process abnormalities in the second redundant calculation function unit without compromising the effect of achieving both cost reduction and high calculation processing power as described above.

[0013] The computing unit includes: an electric brake device stiffness which is a correlation between a motor rotation amount of the electric motor and a braking force; a load conversion efficiency which is a correlation between the motor torque of the electric motor and the braking force; a motor temperature of the electric motor obtained based on a relationship between a voltage and a current of the electric motor or a motor temperature of the electric motor obtained based on a temperature sensor provided in the electric motor; a third redundancy calculation unit is provided that stores a predetermined allowable range or information about the allowable range for a third factor that is at least one of the above, and determines at a predetermined period that the electric brake device is abnormal based on the third factor being out of the allowable range; the period of the third redundant calculation unit is equal to or longer than the period of the third control calculation unit; The priority of the third redundant calculation unit may be set lower than the priority of the third control calculation unit. The third redundant calculation function unit mainly performs processing when a state is determined to be abnormal based on at least some or all of the results of the above estimations (such as state estimation results) in the third control calculation function unit. Therefore, due to the relationship between the period and priority described above, abnormality processing can be performed in the third redundant calculation function unit without compromising the effect of achieving both cost reduction and high calculation processing power as described above. Effect of the Invention

[0014] The electric brake device according to the present invention can achieve both cost reduction and high computational processing capacity. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic block diagram showing an example of a configuration including an electric brake device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is an operational transition diagram showing an example of the operation of the electric brake device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] FIG. 1 shows the configuration of an electric brake device 1 including at least an electric brake control device (hereinafter, also simply referred to as a brake control device or a control device) 100 and an electric brake actuator (hereinafter, also simply referred to as a brake actuator or an actuator) 200 using an electric motor 210, a linear motion mechanism 240, and the like. The control device 100 controls the electric motor 210 and the like so as to generate a desired braking force, and further performs integrated control of the entire electric brake device 1. The electric brake device 1 may further include a power supply device PW and a brake command means 300 such as a brake pedal. The brake command means 300 outputs information such as a pedal stroke amount. In addition to the brake pedal, various operation means that can be operated by a driver, such as a volume, a joystick, and a switch, may be used as the brake command means 300. In this embodiment, the electric brake device 1 will be described as an example of a braking device mounted on a traveling vehicle, but the configuration of this embodiment may also be applied as a brake device for stopping other devices, such as an elevator device, a power generation device, and an energy storage device such as a flywheel.

[0017] <<Electric brake actuator configuration>> Brake actuator 200 includes at least brake rotor 230, friction material 220 that comes into contact with brake rotor 230 to generate a braking force, electric motor 210, and linear motion mechanism 240, which is a friction material operation means that brings friction material 220 into contact with brake rotor 230 by the rotational force of electric motor 210. Brake actuator 200 may further include a reducer 290, an angle sensor 250 that detects the motor angle, a load sensor 260 that detects the brake load, and a temperature sensor 270 that is provided in the electric motor and measures the motor temperature.

[0018] The electric motor 210 generates a rotational force in a rotor (not shown) by, for example, passing current through a three-phase motor coil (not shown) in an internal stator, and is preferably a permanent magnet synchronous motor because it saves space and provides high efficiency and high torque. The electric motor 210 is not limited to this, and may be, for example, a wound field motor using brushes, a DC motor, a reluctance motor without permanent magnets, or an induction motor. The linear motion mechanism (friction material operating means) 240 is a mechanism that has, for example, various screw mechanisms such as a planetary roller screw and a ball screw, or a ball ramp (not shown), and is capable of converting the rotational motion of the rotor of the electric motor 210 into linear motion.

[0019] The reducer 290 is interposed between the motor 210 and the linear motion mechanism 240, and outputs a rotational speed reduced with respect to the rotational input, and may be a parallel gear, a planetary gear, or the like. Alternatively, a worm gear, a harmonic reducer, or the like may be used for the reducer 290. Note that it is also possible to configure the linear motion mechanism 240 directly by the motor 210 without providing this reducer. Generally, it is often preferable to provide a reducer because it allows the electric motor to be made smaller, but when configuring an electric brake device with a relatively small load, it may be preferable to not provide a reducer and to reduce the number of parts.

[0020] The angle sensor 250 can detect the number of rotations (also called the motor rotation amount) or the rotation angle (also called the motor angle) of the rotor of the electric motor 210, and while it is considered preferable to use a resolver or a magnetic encoder, which has high accuracy and high reliability, various sensors such as an optical encoder can also be used. Note that, without using an angle sensor, it is also possible to use angle sensorless estimation, in which the motor angle is estimated from the relationship between the voltage and current of the electric motor 210 in the electric brake control device 100 described later, for example.

[0021] The load sensor 260 detects the braking force or load (force) between the brake rotor 230 and the friction material 220. For example, a sensor that detects distortion or deformation caused by a load acting on the actuator 200 due to the braking force or the like is considered to be inexpensive and highly accurate, but a pressure-sensitive medium such as a piezoelectric element may also be used. Alternatively, a torque sensor that detects the braking torque of the brake rotor 230 or an acceleration sensor that detects the longitudinal deceleration of the vehicle in the case of an electric brake device for a vehicle may be used as the load sensor 260. Alternatively, a sensorless estimation may be performed without providing a load sensor based on a predetermined correlation such as the electric brake device stiffness that is a correlation between the braking force and the motor angle or the motor rotation amount of the electric motor 210, and the load conversion efficiency that is a correlation between the braking force or the like and the motor torque of the electric motor 210.

[0022] The temperature sensor 270 measures the motor temperature of the electric motor 210, and is preferably a thermistor whose resistance changes with temperature, for example, since it allows for low-cost temperature detection. It is also possible to use the motor temperature obtained based on the relationship between the current and voltage of the electric motor 210 and further based on this relationship and the motor angular speed, without using a temperature sensor. In addition, various sensors such as a thermistor and a parking brake function that locks the mechanism to hold the braking force may be provided separately as elements not shown in the figure according to requirements. As the parking brake function, for example, a configuration that locks a drive unit such as a reducer using a solenoid or a DC motor can be applied.

[0023] <<Electric brake control device configuration>> The control device 100 is composed of a computing unit FU, which is composed of software and / or hardware and has various computing functions including each computing unit described later, and other hardware such as sensors and drivers. For the computing unit FU, it is preferable to use, for example, a microcomputer, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), etc., because it is inexpensive and has high performance. The computing unit FU receives at least a command value (target braking force, the above-mentioned pedal stroke amount, etc.) from the brake command means 300, and includes at least a first control computing unit 110 and a second control computing unit 120, and may further include a third control computing unit 130, a first redundant computing unit 160, a second redundant computing unit 170, a third redundant computing unit 180, and a computation priority setting unit 190. The computing unit FU will be described in detail later.

[0024] As an example of a sensor, the current sensor CS measures the value of the current flowing through the electric motor 210. The current sensor CS may be, for example, a sensor consisting of an amplifier that detects the voltage across a shunt resistor, or a non-contact sensor that detects the magnetic flux around the current path. The current sensor CS may be provided in the current path from the motor driver to each phase of the motor coil, or may be provided in some (multiple) of the phases. Alternatively, the current sensor CS may be provided on either the positive or negative side of the power supply of the current path from the power supply to the motor driver, and may be configured to estimate the current of each phase of the motor coil. Alternatively, the current sensor may not be used, and the current value may be estimated by detecting, for example, a voltage drop of an element that constitutes the motor driver.

[0025] As an example of a driver, the motor driver MD is a bridge circuit using switching elements (or simply switch elements) such as FETs (Field Effect Transistors), and is considered to be suitable for low cost and high performance when configured to perform PWM (Pulse Width Modulation) control that determines the motor applied voltage based on a predetermined duty ratio (the ratio of on-time or off-time to the total switching time). Alternatively, the motor driver MD can be provided with a transformer circuit or the like that makes the motor applied voltage variable, and configured to perform PAM (Pulse Amplitude Modulation) control that adjusts the motor applied voltage.

[0026] As an example of another hardware, the motor power circuit breaker BR is a switch circuit such as a relay provided in, for example, a power path from the power supply device PW to the motor driver MD, or a power path from the motor driver MD to a reference potential such as GND (ground), or both. The motor power circuit breaker BR has a function of receiving a signal corresponding to an instruction to supply or cut off power from a predetermined redundancy calculation unit or the like described below, and supplying or cutting off power from the power supply device PW to the electric motor 210.

[0027] <First control calculation unit> The first control calculation unit 110 includes at least a motor current control calculation unit 111, a current estimation unit 113, and a motor phase estimation unit 115. The current estimation unit 113 has a function of estimating a motor current from the output of the current sensor CS based on a predetermined conversion formula or the like. The motor phase estimation unit 115 has a function of deriving an electrical angle phase used for motor control or the like using the output of the angle sensor 250. When a motor that does not require an electrical angle phase, such as a DC motor, is used, the motor phase estimation unit 115 can be omitted. The motor current control calculation unit 111 derives and determines motor coil energization conditions (conditions such as motor currents of each phase, motor voltages of each phase or between each phase, etc.) for exerting (achieving) a desired motor drive amount or drive force of the electric motor 210 based on a predetermined control calculation formula, and outputs an operation signal corresponding to the result to the motor driver. The operation signal can be a switching signal for achieving a predetermined applied voltage when performing PWM control, for example.

[0028] The first control calculation unit 110 has a function of determining the energization conditions of the motor coil so as to exert a desired driving force of the electric motor by the above configuration, and the above determination process is executed at a predetermined (calculation) period. In the above, an example was shown in which the first control calculation unit 110 is configured to include the motor current control calculation unit 111, the current estimation unit 113, and the motor phase estimation unit 115. Of these, the motor current control calculation unit 111 is a function that is always included in the first control calculation unit 110, but the current estimation unit 113 and the motor phase estimation unit 115 may not be included in the first control calculation unit 110 due to design reasons or the like. However, it is considered preferable to include the current estimation unit 111 and the motor phase estimation unit 115 in the first control calculation unit 110 as described above, since it is easy to design the control.

[0029] <Second control calculation unit> The second control calculation unit 120 includes at least a brake force control calculation unit 121, a motion state estimation unit 123, and a brake force estimation unit 125. The motion state estimation unit 123 has a function of estimating the motor angle and motor angular velocity of the rotor of the electric motor 210 based on the output of the angle sensor 250. Alternatively, the motion state estimation unit 123 may be provided with a function of calculating a predetermined differential and integral value such as a motor angular acceleration from the output of the angle sensor 250, or a function of estimating a load equivalent to a disturbance based on the motor angle and the motor operation amount. In addition, the motor angle, motor angular velocity, and motor angular acceleration may be, instead of a direct measurement value from the rotor of the electric motor, an angle calculated based on a reduction ratio of a predetermined part of the reducer 290, or a position or velocity of the friction material 220 calculated based on an equivalent lead of the linear motion mechanism 240. In the estimation in this embodiment, an estimation algorithm such as a state estimation observer may be used, or a direct calculation such as a back calculation from differentiation or inertia may be used.

[0030] The brake force estimation unit 125 has a function of estimating the brake force based on a predetermined conversion formula or the like from the output of the load sensor 260. When a load sensor is not provided, the brake force may be estimated from the estimation result of the motion state estimation unit 123 and the above-mentioned preset electric brake device stiffness, or may be estimated from the estimation result of the current estimation unit 113 and the above-mentioned preset load conversion efficiency. The brake force control calculation unit 121 has a function of determining a target motor drive amount (hereinafter also referred to as a target drive force) of the electric motor 210 so that the electric brake actuator 200 performs a desired follow-up operation with respect to a desired brake force target value. The target motor drive amount may be expressed, for example, as a target motor current for generating a desired motor torque or brake force.

[0031] The second control calculation unit 120 has a function of determining a target driving force of the electric motor 210 required to exert a desired braking force by the above configuration, and the above determination process and the like are executed at a predetermined period longer than the period of the first control calculation unit 110. In the above, an example was shown in which the second control calculation unit 120 is configured to include the braking force control calculation unit 121, the braking force estimation unit 125, and the motion state estimation unit 123, but among these, the braking force control calculation unit 121 is a function that is always included in the second control calculation unit, but the braking force estimation unit 125 and the motion state estimation unit 123 may be configured not to be included in the second control calculation unit 120 due to design convenience, etc. However, it is considered preferable to configure the second control calculation unit 120 to include the braking force estimation unit 125 and the motion state estimation unit 123 as described above, since it is easy to design the control.

[0032] Here, in particular, the motion state estimation unit 123 is included in the second control calculation unit 120 in this embodiment, but may be included in the first control calculation unit 110, and the estimation result of the motion state estimation unit 123 may be referred to by the motor current control calculation unit 111. In this way, for example, when determining current conditions according to the motor angular velocity, control that more precisely reflects the motor motion state can be executed, which is particularly effective when applying a small motor with a large power rate whose motion state is likely to change significantly during one calculation cycle. However, on the other hand, for reasons described later, the first control calculation unit 110 is executed in a relatively short calculation cycle, so the calculation load increases relatively. Which of these trade-offs is given more importance is determined according to design convenience, etc.

[0033] <Third control calculation unit> The third control calculation unit 130 includes at least a brake stiffness estimation unit 131, a load conversion efficiency estimation unit 133, and a motor temperature estimation unit 135. The brake stiffness estimation unit 131 has a function of estimating the brake device stiffness, which is a correlation between the brake force and the motor angle (or the pedal stroke amount or the like that may be synchronized with the motor angle) or the motor rotation amount, from the estimation results of the motion state estimation unit 123 and the braking force estimation unit 125. The load conversion efficiency estimation unit 133 has a function of estimating the motor torque that the electric motor 210 can generate from the target motor drive amount (target drive force) calculated in the braking force control calculation unit 121, and estimating the load conversion efficiency, which is a correlation between the motor torque and the braking force, from this motor torque and the braking force estimated by the braking force estimation unit 125. Alternatively, the load conversion efficiency estimation unit 133 may obtain a motor current estimation value from the current estimation unit 113 instead of the target motor drive amount, and estimate the motor torque generated by the electric motor 210 from the motor current estimation value.

[0034] The motor temperature estimation unit 135 has a function of estimating the motor temperature from the output of the temperature sensor 270 provided in the electric motor 210. Alternatively, the motor temperature estimation unit 135 may estimate the motor temperature based on the relationship between the voltage and current of the electric motor and the temperature dependency of the motor coil, which are stored in advance. For example, the motor temperature estimation unit 135 can use the motor applied voltage determined in the motor current control calculation unit 111, the motor current estimated value estimated in the current estimation unit 113, and the motor angular velocity estimated in the motion state estimation unit 123 to estimate the resistance value of the motor coil from a motor state equation including these values, and estimate the motor temperature from the correlation of the temperature dependency of the resistance of the motor coil, which is determined in advance.

[0035] The third control calculation unit 130 has a function of estimating the state of the electric brake device, for example, a function of estimating at least one of the electric brake device stiffness, the load conversion efficiency, and the motor temperature, and the estimation process is performed at a predetermined period longer than the period of the second control calculation unit. In the above, an example has been shown in which the third control calculation unit 130 is configured to include the brake stiffness estimation unit 131, the load conversion efficiency estimation unit 133, and the motor temperature estimation unit 135, but it may include at least one or more functions of these.

[0036] <First redundant calculation unit> The first redundancy calculation unit 160 is composed of at least a current abnormality redundancy control unit 161 and a motor current abnormality estimation unit 163. The motor current abnormality estimation unit 163 has a function of estimating an abnormality related to the motor current from the motor current supply conditions determined by the motor current control calculation unit 111 and the output of the current sensor CS. This function estimates some or all of the following: an abnormality such as a short circuit or disconnection of some or multiple elements in the motor driver MD, an abnormality such as a short circuit or disconnection of a bus bar or harness (not shown) that is a connection between the motor driver MD and the electric motor 210, an abnormality such as a short circuit or disconnection of the motor coil, an abnormality in the current sensor CS, an abnormality in the motor power supply to the motor driver MD, etc.

[0037] The motor current abnormality estimation unit 163 may have a function of judging whether the electric motor 210 is being energized as expected, based on, for example, the motor energization conditions determined by the motor current control calculation unit 111 and the output of the current sensor CS, whether they are outside a predetermined allowable range. When any of the above abnormalities occur, the expected energization is not possible, so that the judgment function can estimate that any of the above abnormalities has occurred. The allowable range represents, for example, the range of so-called normal operation, and is determined by an upper limit value and a lower limit value determined by the results of a simulation, experiment, or measurement (the same applies below).

[0038] At this time, in addition to the above-mentioned energization conditions and output values, for example, the estimation result of the angular velocity of the motion state estimation unit 123 may also be used, in which case a highly accurate judgment can be made that is more in line with the driving state of the motor. Alternatively, the output voltage of the motor driver MD may be directly measured instead of the motor energization conditions, or the estimation result of the current estimation unit 113 may be acquired instead of the output of the current sensor CS. These can be determined by the designer for convenience of design, etc. In addition, the function of the motor current abnormality estimation unit 163 may be, for example, a function of acquiring a control parameter in the motor current control calculation unit 111 and judging whether or not it is out of a predetermined allowable range to judge whether the electric motor 210 is energized as expected. For example, if the motor current control calculation unit 111 has a feedback control function including an integration function of the control deviation, when the electric motor 210 cannot be energized as expected, the integral value increases, decreases, or saturates unexpectedly, and this can also be used to judge an abnormality.

[0039] The motor current abnormality estimation unit 163 may have a function of judging whether there is a sign of abnormality in the output of the current sensor CS, for example. For example, when the output of the current sensor CS falls outside a predetermined output range (such as a tolerance range), it can be estimated that a short circuit has occurred in any of the current paths, or that an abnormality has occurred in the current sensor CS. Alternatively, the motor current abnormality estimation unit 163 may have a function of judging an abnormality when the current abnormality is judged to be a state in which ...

[0040] The current abnormality redundancy control unit 161 has a function of executing fail-safe control or the like so as to satisfy the safety goal of the electric brake device 1 when the motor current abnormality estimation unit 163 judges that there is an abnormality. In particular, since the situation judged as abnormal by the motor current abnormality estimation unit 163 is mainly a situation in which the motor cannot be driven satisfactorily, it is preferable to cut off the power supply to the electric motor 210 to prevent fire, dangerous operation, and the like. In this embodiment, a configuration is shown in which the motor power breaker BR can be operated, and the power supply to the electric motor 210 can be cut off by the motor power breaker BR in the event of the above-mentioned abnormality. Alternatively, a process may be provided in which a certain time from the time when the motor current abnormality estimation unit 163 judges that there is an abnormality is set as a grace time for performing motor operation in order to reach a safer state.

[0041] The first redundancy calculation unit 160 mainly has a function of estimating an abnormality that may impair the function of the first control calculation unit 110 and performing processing when an abnormality occurs, and for example, a predetermined allowable range or information regarding the allowable range is stored, and for a first factor, which is either the voltage or current of the electric motor 210 or the relationship between the voltage and current, it determines that the electric brake device is abnormal based on the fact that the first factor is outside the allowable range, and the above-mentioned determination processing and the like are performed at a predetermined period that is the same as or longer than the period of the first control calculation unit 110 and shorter than the period of the second control calculation unit 120. In the above, an example is shown in which the first redundancy calculation unit 160 is configured to include a motor current abnormality estimation unit 163 and a current abnormality redundancy control unit 161.

[0042] The motor motion abnormality estimation unit 173 has a function of estimating an abnormality related to the motor rotational motion based on a judgment of whether or not the target motor drive amount (target drive force) calculated by the braking force control calculation unit 121 and the estimated result of the motor motion estimated by the motion state estimation unit 123 are outside a predetermined allowable range. This function estimates some or all of, for example, the sticking or increase in operating resistance of the electric motor 210, the speed reducer 290, the linear motion mechanism 240, etc., motor torque abnormality, motor angle sensor abnormality, etc. In addition, as a function of the motor current abnormality estimation unit 163, for example, it can estimate the motor torque that the motor can generate from the target motor drive amount calculated by the braking force control calculation unit 121, derive, for example, an allowable range in which the motor angle or motor angular velocity of the electric motor 210 is considered to be operating normally based on a motion equation using at least the moment of inertia of the electric brake device 1, and determine that an abnormality has occurred when the estimated result of the motor angle or motor angular velocity estimated by the motion state estimation unit 123 is outside the allowable range. The above-mentioned moment of inertia is preferably a value obtained by converting the inertia of the electric brake device 1, including the electric motor 210 (rotor, etc.), the reducer 290, the linear motion mechanism 240, etc., into a predetermined operating axis, and it is considered preferable to convert it into an equivalent moment of inertia on the rotating shaft (not shown) of the electric motor 210, as this makes the calculation easier.

[0043] <Second redundant calculation unit> The second redundancy calculation unit 170 includes at least a motion abnormality redundancy control unit 171 and a motor motion abnormality estimation unit 173. The motion abnormality redundancy control unit 171 has a function of operating to satisfy the safety goal of the electric brake device 1 when an abnormality is determined by the motor motion abnormality estimation unit 173 described later, and for example, a predetermined allowable range or information on the allowable range is stored, and for at least a second factor, which is a relationship between the driving force (or driving amount) of the electric motor 210 and the motor rotation amount, the second factor is determined to be abnormal at a predetermined period based on the fact that the second factor falls outside the allowable range, and a fail-safe control or the like is executed. Specifically, the second redundancy calculation unit 170 can be configured to input, for example, a command to make the target motor driving amount (target driving force) approximately zero to the braking force control calculation unit 121. Alternatively, the second redundancy calculation unit 170 may be configured to input, to the braking force control calculation unit 121, a command to limit the maximum value of the braking force that can be generated to a value smaller than that in normal times, and these can be used in combination as appropriate. In addition, for example, when an abnormal load increase such as sticking occurs during brake pressure increase, a command may be input to the braking force control calculation unit 121 to release the brake for a certain period of time. The motor motion abnormality estimation unit 173 judges whether the motor operation based on the output result of the braking force control calculation unit 121 is normal or abnormal by referring to the output of the motion state estimation unit 123, etc.

[0044] The second redundant calculation unit 170 mainly has a function of estimating an abnormality that may impede the function of the second control calculation unit 120 and performing processing when the abnormality occurs, and the above-mentioned judgment processing and the like may be performed at a predetermined period that is the same as or longer than the period of the second control calculation unit 120 and is shorter than the period of the third control calculation unit 130. In the above, an example is shown in which the second redundant calculation unit 170 is configured to include a motor movement abnormality estimation unit 173 and a movement abnormality redundancy control unit 171.

[0045] <Third redundant calculation unit> The third redundancy calculation unit 180 includes at least an actuator abnormality redundancy control unit 181 and an actuator abnormality estimation unit 183. The actuator abnormality estimation unit 183 has a function of judging that an estimated result of a third factor, which is at least one of the estimated result of the stiffness of the electric brake device estimated by the brake stiffness estimation unit 131, the estimated result of the load conversion efficiency estimated by the load conversion efficiency estimation unit 133, and the estimated result of the motor temperature estimated by the motor temperature estimation unit 135, is abnormal when the estimated result falls outside a predetermined allowable range in which the electric brake device can be estimated to be normal as described above or information on the allowable range is stored in advance. The actuator abnormality redundancy control unit 181 has a function of performing fail-safe control or the like so as to satisfy the safety goal of the electric brake device 1 when the actuator abnormality estimation unit 183 judges that the electric brake device 1 is abnormal. Specifically, for example, the actuator abnormality estimation unit 183 may be configured to input a command to the brake force control calculation unit 121 to limit the maximum value of the brake force that can be generated to a value smaller than that during normal operation. Alternatively, it may perform the same operation as the aforementioned movement abnormality redundancy control unit 171, but since the seriousness of the abnormality and the urgency of the need to deal with it are considered to be relatively lower than when an abnormality is judged by the movement abnormality redundancy control unit 171, it is considered preferable to implement it as a process that limits the functions of the electric brake device 1 and continues operation as much as possible.

[0046] The third redundancy calculation unit has a function of performing processing when a state that may be determined as abnormal is determined based mainly on at least any or all of the state estimation results in the third control calculation unit 130, and the above-mentioned determination processing etc. may be performed at a predetermined period that is the same as or longer than the period of the third control calculation unit 130. In the above, an example is shown in which the third redundancy calculation unit is configured to include an actuator abnormality estimation unit 183 and an actuator abnormality time redundancy control unit 181.

[0047] <Calculation priority setting section> The calculation priority setting unit 190 has a function of setting the priority of each of the above-mentioned calculation units, which are typically executed in different cycles, and managing and adjusting which process is to be executed with priority when the execution timings of the calculation units conflict. For example, the calculation priority setting unit 190 has a function of pausing or not starting the calculation of the other calculation units with lower priority until the calculation of the calculation unit with higher priority is executed and completed. Specifically, when the first control calculation unit 110 and the second control calculation unit 120 conflict with each other, the first control calculation unit 110 is given priority in executing the calculation process. Also, when the third control calculation unit 130 conflicts with the second control calculation unit 120, the calculation process of the second control calculation unit 120 may be given priority in executing. In this case, when the third control calculation unit 130 conflicts with the first control calculation unit 110, the first control calculation unit 110 is necessarily given priority.

[0048] Moreover, when the first redundant calculation unit 160 and the first control calculation unit 110 compete with each other, the calculation process of the first control calculation unit 110 may be executed with priority. When the first redundant calculation unit 160 and the second control calculation unit 120 or the third control calculation unit 130 compete with each other, the first redundant calculation unit 160 may be executed with priority. When the second redundant calculation unit 170 and the second control calculation unit 120 compete with each other, the second control calculation unit 120 may be executed with priority. When the second redundant calculation unit 170 and the third control calculation unit 130 compete with each other, the second redundant calculation unit 170 may be executed with priority. When the third redundant calculation unit 180 and the third control calculation unit 130 compete with each other, the calculation process of the third control calculation unit 130 may be executed with priority.

[0049] <<Power supply>> For example, in an electric brake device for an automobile, the power supply device PW may use a low-voltage battery, a high-voltage battery and a step-down converter that steps down the voltage, or a high-capacity capacitor, etc. Alternatively, the power supply device PW may use these in parallel for redundancy and connect them to the current path.

[0050] <<Other>> In addition, the following may also be possible. For example, in system operation, it is considered that a startup program from when the power is turned on and a communication means for transmitting information to other higher-level ECUs (Electronic Control Units) and the like will be necessary, and these should be provided as appropriate. In addition, for example, in this embodiment, only the current abnormality redundancy control unit 161 is connected to operate the motor power circuit breaker BR, but this does not mean that only the current abnormality redundancy control unit 161 has the function of operating the motor power circuit breaker BR, and operation input to the motor power circuit breaker for system reasons such as at startup or in standby mode should also be appropriately performed by other computing units or external modules.

[0051] In addition, the first redundant calculation unit 160 may be a function integrated with the first control calculation unit 110, the second redundant calculation unit 170 may be a function integrated with the second redundant calculation unit 120, and the third redundant calculation unit 180 may be a function integrated with the third control calculation unit 130. When these configurations are adopted, these integrated control calculation units and redundant calculation units will necessarily perform calculations in the same cycle without their respective processes competing with each other. The same applies to the priority. Whether these are independent or integrated functions is to be determined arbitrarily according to design convenience, etc.

[0052] FIG. 2 shows an example of an operation sequence of the first to third control calculation units and the first to third redundant calculation units in the electric brake control device 100 in this embodiment. In the figure, the vertical axis represents the time axis, and the execution standby process EW and each of the above-mentioned calculation units are listed in order from left to right along the horizontal axis. Each solid-line rectangle intermittently shown in the vertical (time) direction from the execution standby process EW and each calculation unit indicates that the execution standby process EW and each calculation unit are operating (processing), and the length of the rectangle shows that the processing is being executed for a predetermined time. Also, each dashed-line rectangle in the figure indicates that the processing is waiting to start (when written above the solid-line rectangle in the vertical axis direction of the figure) or that the processing is temporarily suspended (when written between two solid-line rectangles in the vertical axis direction of the figure). The top side of the solid-line rectangle or dashed-line rectangle in the vertical axis direction of each processing represents the start position of the processing, and the interval of the start positions in the vertical axis direction represents the period of the calculation or processing of each calculation unit described above.

[0053] In the figure, the (calculation) period of the first control and calculation unit 110 is represented by Tc1, the period of the second control and calculation unit 120 is represented by Tc2, and the period 130 of the third control and calculation unit is represented by Tc3. Here, in the figure, the period Tc2 of the second control and calculation unit 120 and the period Tc3 of the third control and calculation unit 130 may start from the upper side of the dashed rectangle, and during the time of the dashed rectangle, the second control and calculation unit and the third control and calculation unit each start processing but are in a waiting state, and then each starts processing according to their respective priorities (the part indicated by the solid line rectangle following the dashed rectangle). Note that, since the first control and calculation unit 110 of this embodiment has the highest priority as described above, it is not in a waiting state for starting processing like the other calculation units, and therefore it is not started from the upper side of the dashed rectangle.

[0054] Also, the period of the first redundant arithmetic unit is represented by Tr1, the period of the second redundant arithmetic unit by Tr2, and the period of the third redundant arithmetic unit by Tr3. Here, in the figure, the period Tr1 of the first redundant arithmetic unit, the period Tr2 of the second redundant arithmetic unit, and the period Tr3 of the third redundant arithmetic unit may start from the upper side of the dashed rectangle (in the figure, all three redundant arithmetic units start from the upper side of the dashed rectangle), and during the time of the dashed rectangle, the first redundant arithmetic unit, the second redundant arithmetic unit, and the third redundant arithmetic unit each start processing but are in a standby state, and then each starts processing according to their respective priorities (the portion followed by the solid line rectangle after the dashed line rectangle).

[0055] Here, the execution standby process EW described on the left side is a general term for the process during the time when the first to third control and arithmetic units and the first to third redundant arithmetic units are not executed. The execution standby process EW may be a process in which no calculation is performed during this time, or may be a process in which any calculation with a relatively low priority that is not included in the first to third control and arithmetic units and the first to third redundant arithmetic units is executed, and is arbitrarily determined by the designer. Therefore, the priority of the execution standby process EW may be set lower than that of the first to third control and arithmetic units and the first to third redundant arithmetic units. However, it is preferable that the start-up sequence after power-on (for example, execution of an instruction from address zero of a program in a microcomputer) is completed before the first to third control and arithmetic units and the first to third redundant arithmetic units are executed. It is preferable that the communication process with other control devices (such as a higher-level ECU) can be performed in parallel with other processes, for example, by another dedicated hardware or a dedicated processing module provided in a computing unit.

[0056] As described above, in the figure, the second control operation unit 120 has a longer cycle than the first control operation unit 110, and the third control operation unit 130 has a longer cycle than the second control operation unit 120. Also, the first redundant operation unit 160 has a cycle that is the same as or longer than the first control operation unit 110 and shorter than the second control operation unit 120, the second redundant operation unit 170 has a cycle that is the same as or longer than the second control operation unit 120 and shorter than the third control operation unit 130, and the third redundant operation unit 180 is executed at a cycle that is the same as or longer than the third control operation unit 130. For simplicity in this figure, the first redundant operation unit 160 is assumed to have the same operation cycle as the first control operation unit 110, the second redundant operation unit 170 is assumed to have the same operation cycle as the second control operation unit 120, and the third redundant operation unit 180 is assumed to have the same operation cycle as the third control operation unit 130.

[0057] The specific calculation period of each process is arbitrarily determined by the designer, but as a design example, the (calculation) period of the first control calculation unit and the first redundant calculation unit can be about 0.01 to 0.1 msec, the period of the second control calculation unit and the second redundant calculation unit can be about 0.1 to 10 msec, and the period of the third control calculation unit and the third redundant calculation unit can be about 10 to 1000 msec, and each period is adjusted to have the mutual relationship as already described. However, these values ​​should be arbitrarily determined according to the performance requirements of the calculation unit and the response speed, and are not limited to these values. In addition, the present embodiment is intended to illustrate the relative relationship and the concept of priority of the calculation periods of each calculation function unit, and does not show an example that follows the design example of the calculation period described above.

[0058] An example of the operation sequence of each calculation unit will be described. In the figure, the execution standby process EW starts processing at time t1 (solid line rectangle; same below). However, since the execution standby process EW has the lowest priority, when the first control calculation unit 110 starts processing at time t2, the execution standby process EW suspends processing (dashed line rectangle; same below), and the initiative of the processing is transferred from the execution standby process EW to the first control calculation unit 110 (trn1 in the figure). Next, when the first control calculation unit 110 finishes processing, the initiative of the processing is transferred to the first redundant calculation unit 160 (trn2 in the figure). Note that the first redundant calculation unit 160 started processing while the first control calculation unit 110 was processing, but since its priority was relatively low, it was in a start standby state (dashed line rectangle; same below), and when the first control calculation unit 110 finished processing, the start standby state was released and the processing was started. On the other hand, since the execution standby process EW has a lower priority than the first redundant calculation unit 160, it cannot resume its own processing and remains in a temporarily suspended state.

[0059] Next, when the first redundant arithmetic unit 160 finishes the processing, the initiative of the processing is transferred to the second control and arithmetic unit 120 (trn3 in the figure). Note that the second control and arithmetic unit 120 started processing while the first redundant arithmetic unit 160 was processing, but was in a start waiting state because its priority was relatively low. When the first redundant arithmetic unit 160 finished the processing, the start waiting state was released and the execution waiting process EW started its processing. On the other hand, since the priority of the execution waiting process EW is lower than that of the second control and arithmetic unit 120, it cannot resume its own processing here either and remains in the temporarily suspended state.

[0060] Thereafter, the initiative in the processing is similarly transferred to the second redundant calculation unit 170 and the third control calculation unit 130 (trn4 and trn5, respectively). However, when the first control calculation unit 110 starts processing for the next cycle, the initiative in the processing is transferred from the third control calculation unit 130 to the first control calculation unit 110 (trn6), and the third control calculation unit 130 temporarily suspends processing (dashed rectangle; same below). When the first control calculation unit 110 finishes processing, the third control calculation unit 130 resumes the suspended processing (trn8) after the start (trn7) and end of processing of the first redundant calculation unit 160, which has a higher priority.

[0061] Thereafter, when the third control and arithmetic unit 130 finishes its processing, the third redundant arithmetic unit 180 starts its processing (trn9). When the third redundant arithmetic unit 180 finishes its processing, there are no other arithmetic units in a suspended state or in a waiting-to-start state, and no other arithmetic units are in process or have started their processing, so that the initiative in the processing is transferred to the execution standby process EW (trn10), and the processing of the execution standby process EW is started (time t3). When the second control and arithmetic unit 120 starts its processing at time t4, the execution standby process EW suspends its processing, and the initiative in the processing is transferred from the execution standby process EW to the second control and arithmetic unit 120 (trn11 in the figure).

[0062] After that, in the same manner as above, when a processing operation is started in a certain processing element, the initiative of the processing is repeatedly transferred according to its priority (trn12 to trn27 are shown in the figure). During that time, if there are no other processing elements in a suspended state or a waiting-to-start state as described above, and if no other processing elements are in the middle of processing or have started processing, the initiative of the processing is transferred to the execution waiting process EW, and processing of the execution waiting process EW is started (time t5, t7, etc.). If another processing element starts processing during the processing of the execution waiting process EW, the execution waiting process EW suspends its processing, and the initiative of the processing is transferred from the execution waiting process EW to that processing element (time t6, etc.).

[0063] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0064] 1 Electric brake device 100 Control device 110 First control and calculation unit 120 Second control and calculation unit 130 Third control and calculation unit 160 First redundant calculation unit 170 Second redundant calculation unit 180 Third Redundant Calculation Unit 190 Operation priority setting section 210 Electric Motor 220 Friction material 230 Brake rotor 240 Linear motion mechanism (friction material operating means) FU calculator

Claims

1. An electric brake device comprising: a brake rotor; friction material that comes into contact with the brake rotor to generate a braking force; an electric motor; friction material operation means that brings the friction material into contact with the brake rotor by a rotational force of the electric motor; and a control device that controls the electric motor to generate a desired braking force, The control device, a first control calculation unit that determines a motor coil current supply condition of the electric motor at a predetermined period so that the electric motor exerts a desired driving force; a second control calculation unit that determines a target driving force of the electric motor required to exert the desired braking force at a predetermined period; A computing unit provided with The computing device has an operation priority setting unit that sets a priority of each operation unit, and suspends or does not start an operation of another operation unit having a lower priority until the operation of the operation unit having a higher priority is executed and completed, the period of the second control calculation unit is longer than the period of the first control calculation unit, An electric brake device, wherein a priority of the first control calculation unit is set higher than a priority of the second control calculation unit.

2. 2. The electric brake device according to claim 1, The computing unit includes: an electric brake device stiffness which is a correlation between a motor rotation amount of the electric motor and a braking force; a load conversion efficiency which is a correlation between the motor torque of the electric motor and the braking force; a motor temperature of the electric motor obtained based on a relationship between a voltage and a current of the electric motor or a motor temperature of the electric motor obtained based on a temperature sensor provided in the electric motor; a third control calculation unit that estimates at least one of the following at a predetermined period; The period of the third control calculation unit is longer than the period of the second control calculation unit, An electric brake device, wherein a priority of the third control calculation unit is set lower than a priority of the second control calculation unit.

3. 2. The electric brake device according to claim 1, The computing unit includes: a first redundancy calculation unit is provided which stores a predetermined allowable range or information related to the allowable range for a first factor which is either a voltage or a current of the electric motor or a relationship between the voltage and the current, and determines at a predetermined cycle that the electric brake device is abnormal based on the first factor being out of the allowable range; the period of the first redundant calculation unit is equal to or longer than the period of the first control calculation unit; An electric brake device, wherein a priority of the first redundant calculation unit is set lower than a priority of the first control calculation unit.

4. 4. The electric brake device according to claim 3, the period of the first redundant calculation unit is shorter than the period of the second control calculation unit; An electric brake device, wherein a priority of the first redundant calculation unit is set higher than a priority of the second control calculation unit.

5. 2. The electric brake device according to claim 1, The computing unit includes: a second redundancy calculation unit is provided which stores a predetermined allowable range or information relating to the allowable range for a second factor which is at least a relationship between a driving force of the electric motor and an amount of motor rotation, and determines at a predetermined period that the electric brake device is abnormal based on the second factor being out of the allowable range; the period of the second redundant calculation unit is equal to or longer than the period of the second control calculation unit; An electric brake device, wherein a priority of the second redundant calculation unit is set lower than a priority of the second control calculation unit.

6. In the electric brake device according to claims 2 and 5, the period of the second redundant calculation unit is shorter than the period of the third control calculation unit; An electric brake device, wherein a priority of the second redundant calculation unit is set higher than a priority of the third control calculation unit.

7. 7. The electric brake device according to claim 2, The computing unit includes: an electric brake device stiffness which is a correlation between a motor rotation amount of the electric motor and a braking force; a load conversion efficiency which is a correlation between the motor torque of the electric motor and the braking force; a motor temperature of the electric motor obtained based on a relationship between a voltage and a current of the electric motor or a motor temperature of the electric motor obtained based on a temperature sensor provided in the electric motor; a third redundancy calculation unit is provided that stores a predetermined allowable range or information about the allowable range for a third factor that is at least one of the above, and determines at a predetermined period that the electric brake device is abnormal based on the third factor being out of the allowable range; the period of the third redundant calculation unit is equal to or longer than the period of the third control calculation unit; An electric brake device, wherein a priority of the third redundant calculation unit is set lower than a priority of the third control calculation unit.

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