Electromechanical brake control system, motor control device, program, and brake control method

Abstract

To enhance responsiveness in adjusting braking force in an electromechanical brake.SOLUTION: An electromechanical brake control system 1 includes a receiver 10 and a plurality of motor control parts 20. The receiver 10 includes a calculation part 11, and a command information transmission part 12. The calculation part 11 calculates target braking force on the basis of a brake command (a regular brake command). The command information transmission part 12 transmits command information including the target braking force to the plurality of motor control parts 20. Each motor control part 20 includes a command information reception part 21, a power control part 22, a detection part 23, and an adjustment part 24. The command information reception part 21 receives the command information. The power control part 22 controls power to be supplied to a motor 31 on the basis of the command information. The detection part 23 detects at least one of an occurrence of a skid of a wheel, an occurrence of mirror finishing of a wheel and a change in a friction coefficient. The adjustment part 24 adjusts power to be supplied to the motor according to a detection result of the detection part 23 on the basis of the command information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electromechanical brake control system, an electric motor control device, a program, and a brake control method. [Background technology]

[0002] Currently, air brakes, in which friction material is driven by an air cylinder, are used as braking systems for railway vehicles. As an alternative to these air brakes, electromechanical brakes, in which friction material is driven by an electric motor, have been proposed (see, for example, Patent Document 1). When wheel skidding against the rail is detected, skid control is performed to eliminate the skid. In the case of air brakes, a receiver detects skid and controls the anti-skid valve to exhaust the compressed air supplied to the air cylinder, thereby reducing the braking force. In the case of electromechanical brakes, as described in Patent Document 1, a higher-level main control unit detects skid and issues a command to a lower-level electromechanical drive unit to reduce the braking force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Application Publication No. 111959466 Summary of the Invention [Problem to be solved by the invention]

[0004] Regarding skid control in electromechanical brakes, the technology described in Patent Document 1 is configured so that the main control unit determines whether a vehicle is skidding and sends command information reflecting the determination result to the electromechanical drive unit, which means that communication takes time and there is room for improvement in responsiveness. Furthermore, responsiveness is an issue not only in situations where a vehicle is skidding, but also in situations where braking force needs to be adjusted due to changes in the degree of slippage between the friction material and the wheels (changes in the friction coefficient), etc.

[0005] In view of the above circumstances, the present invention aims to provide an electromechanical brake control system, an electric motor control device, a program, and a brake control method that can improve responsiveness when adjusting braking force in an electromechanical brake. [Means for solving the problem]

[0006] As a means for solving the above problems, the present invention has the following configuration. (1) One aspect of the present invention is an electromechanical brake control system including a power receiver and a plurality of electric motor control units that control, in accordance with command information transmitted from the power receiver, each of the electric motors of a plurality of braking units for braking each of a plurality of wheels of a vehicle. The power receiver has a calculation unit that calculates, based on a braking command, a target braking force of the braking unit that transmits power from the electric motor to drive a friction material to brake the wheel, and a command information transmission unit that transmits the command information including the calculated target braking force to the plurality of electric motor control units. The electric motor control units each have a command information receiving unit that receives the transmitted command information, and a front The electromechanical brake control system includes: a power control unit that controls the power supplied to the electric motor based on the command information; a detection unit that detects at least one of the occurrence of wheel skid, the occurrence of wheel mirroring, and a change in the coefficient of friction between the wheel and the contact surface with the friction material or the rail based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; and an adjustment unit that adjusts the power supplied to the electric motor based on the command information in accordance with the detection result of the detection unit.

[0007] In this configuration, the motor control unit detects at least one of the occurrence of wheel skidding, the occurrence of wheel mirroring, and the friction coefficient between the friction material and the contact surface of the wheel, and adjusts the power supplied to the motor based on command information in accordance with the detection results, thereby shortening the time it takes to adjust the power supplied to the motor based on command information in accordance with the detection results. Therefore, with this configuration, it is possible to improve responsiveness when adjusting the power supplied to the motor based on command information in accordance with the detection results.

[0008] (2) In the electromechanical brake control system described in (1) above, the detection unit may detect the occurrence of wheel slippage based on the measurement results of the wheel speed, and the adjustment unit may reduce the power supplied to the electric motor based on the command information when the detection unit detects the occurrence of wheel slippage.

[0009] In this configuration, the electric motor control unit can detect the occurrence of wheel slide and reduces the power supplied to the electric motor based on the command information when wheel slide is detected, thereby shortening the time it takes to reduce the power supplied to the electric motor based on the command information in response to the occurrence of wheel slide. Therefore, with this configuration, it is possible to improve responsiveness when reducing the power supplied to the electric motor based on the command information in response to the occurrence of wheel slide.

[0010] (3) In the electromechanical brake control system described in (1) above, the detection unit may detect the occurrence of mirror-finishing of the wheel based on the pressing force, and the adjustment unit may increase the power supplied to the electric motor based on the command information when the detection unit detects the occurrence of mirror-finishing of the wheel.

[0011] In this configuration, the electric motor control unit can detect the occurrence of wheel specularity and increases the power supplied to the electric motor based on command information when the occurrence of wheel specularity is detected, thereby shortening the time it takes to increase the power supplied to the electric motor based on command information in response to the occurrence of wheel specularity. Therefore, this configuration can improve responsiveness when increasing the power supplied to the electric motor based on command information in response to the occurrence of wheel specularity. Increasing the power supplied to the electric motor increases the pressing force pressing the friction material against the wheel contact surface, causing the wheel to become rough, thereby eliminating wheel specularity. In other words, this configuration can improve responsiveness in eliminating wheel specularity when wheel specularity occurs.

[0012] (4) In the electromechanical brake control system described in (1) above, the detection unit may detect a change in the friction coefficient between the wheel and the contact surface of the friction material or the rail based on the measurement results of the temperature of the friction material and the wheel speed, and the adjustment unit may reduce the power supplied to the electric motor based on the command information when the detection unit detects an increase in the friction coefficient, and increase the power supplied to the electric motor based on the command information when the detection unit detects a decrease in the friction coefficient.

[0013] In this configuration, the electric motor control unit can detect changes in the coefficient of friction between the friction material and the contact surface of the wheel and between the rail and the contact surface of the wheel, and reduces the power supplied to the electric motor based on the command information when an increase in the friction coefficient is detected, and increases the power supplied to the electric motor based on the command information when a decrease in the friction coefficient is detected, thereby shortening the time it takes to reduce the power supplied to the electric motor based on the command information in response to an increase in the friction coefficient and the time it takes to increase the power supplied to the electric motor based on the command information in response to a decrease in the friction coefficient. Therefore, with this configuration, it is possible to improve the responsiveness when reducing the power supplied to the electric motor based on the command information in response to an increase in the friction coefficient and when increasing the power supplied to the electric motor based on the command information in response to a decrease in the friction coefficient.

[0014] (5) In the electromechanical brake control system described in (1) above, the motor control unit may have a notification information sending unit that, when the adjustment unit is adjusting the power supplied to the motor based on the command information, sends notification information to the receiver including a notification that the adjustment unit is adjusting the power supplied to the motor based on the command information, and the receiver may have a notification information receiving unit that receives the sent notification information.

[0015] In this configuration, when adjusting the power supplied to the electric motor, each electric motor control unit transmits notification information to the receiver, including a notification that the adjustment is being made. Therefore, with this configuration, the receiver can grasp the implementation status of power adjustment in each electric motor control unit, thereby enhancing safety. The notification information is useful for future improvements and developments of electromechanical brake control systems.

[0016] (6) In the electromechanical brake control system described in (2) above, the adjustment unit may increase the power supplied to the electric motor when the detection unit does not detect the occurrence of wheel slippage and the adjustment unit of another electric motor control unit reduces the power supplied to the electric motor.

[0017] In this configuration, the motor control unit increases the power when no slide is occurring and the other motor control units decrease the power in response to the occurrence of slide, thereby ensuring the overall braking force.

[0018] (7) In the electromechanical brake control system described in (2) or (4) above, the motor control unit may have an emergency command receiving unit that receives an emergency command, the power control unit may prioritize the emergency command over the command information and control the power supplied to the motor based on the emergency command, and the adjustment unit may adjust the power supplied to the motor based on the emergency command in accordance with the detection result of the detection unit.

[0019] In this configuration, the motor control unit adjusts the power supplied to the motor based on the emergency command in accordance with the detection result, thereby shortening the time it takes to adjust the power supplied to the motor based on the emergency command in accordance with the detection result. Therefore, this configuration can improve responsiveness when adjusting the power supplied to the motor based on the emergency command in accordance with the detection result. In other words, responsiveness can be improved even in an emergency such as when an emergency brake is applied, and the braking distance can be shortened, for example.

[0020] (8) One aspect of the present invention is an electric motor control device that controls an electric motor of a braking unit for braking the wheels of a vehicle, and includes: a command information receiving unit that receives command information including a target braking force of the braking unit calculated based on a braking command; a power control unit that controls power supplied to the electric motor based on the command information; a detection unit that detects at least one of the occurrence of wheel skidding, the occurrence of wheel mirroring, and a change in the friction coefficient between the wheel and the friction material of the braking unit or the contact surface with the rail based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material of the braking unit against the contact surface of the wheel, the state of the rail on which the vehicle is traveling, and the state of the wheel; and an adjustment unit that adjusts the power supplied to the electric motor based on the command information in accordance with the detection result of the detection unit.

[0021] According to this configuration, similar to the electromechanical brake control system described in (1) above, it is possible to improve the responsiveness when adjusting the power supplied to the electric motor based on the command information in accordance with the detection result.

[0022] (9) One aspect of the present invention is an electromechanical brake control system including a receiver and a plurality of motor control devices that control, in accordance with command information transmitted from the receiver, each of the electric motors of a plurality of braking units for braking each of a plurality of wheels of a vehicle. The program causes a first computer to function as the receiver and a second computer to function as the motor control device, and causes the first computer to function as a calculation means that calculates, based on a braking command, a target braking force of the braking unit that transmits power from the electric motor to drive a friction material to brake the wheel, and a command information transmission means that transmits the command information including the calculated target braking force, and causes the second ... command information transmission means that transmits the command information including the calculated target braking force. The program causes a computer to function as: command information receiving means for receiving the transmitted command information; power control means for controlling the power supplied to the electric motor based on the command information; detection means for detecting at least one of the occurrence of wheel skid, the occurrence of wheel mirroring, and a change in the coefficient of friction between the wheel and the contact surface with the friction material or the rail, based on at least one measurement result of the wheel speed, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; and adjustment means for adjusting the power supplied to the electric motor based on the command information in accordance with the detection result by the detection means.

[0023] According to this configuration, similar to the electromechanical brake control system described in (1) above, it is possible to improve the responsiveness when adjusting the power supplied to the electric motor based on the command information in accordance with the detection result.

[0024] (10) One aspect of the present invention is a program for causing an electric motor control device that controls an electric motor of a braking unit for braking the wheels of a vehicle to function as a computer, the program causing the computer to function as: command information receiving means that receives command information including a target braking force of the braking unit calculated based on a braking command; power control means that controls the power supplied to the electric motor based on the command information; detection means that detects at least one of the occurrence of wheel skid, the occurrence of wheel mirroring, and a change in the friction coefficient between the wheel and the friction material of the braking unit or the contact surface with the rail based on at least one measurement result of the wheel speed of the wheel, the pressing force that presses the friction material of the braking unit against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; and adjustment means that adjusts the power supplied to the electric motor based on the command information in accordance with the detection result by the detection means.

[0025] According to this configuration, similar to the electromechanical brake control system described in (1) above, it is possible to improve the responsiveness when adjusting the power supplied to the electric motor based on the command information in accordance with the detection result.

[0026] (11) One aspect of the present invention is a brake control method using a receiver and a plurality of motor control devices that control each of a plurality of electric motors of a plurality of braking units for braking each of a plurality of wheels of a vehicle in accordance with command information transmitted from the receiver, the method including: a calculation step using the receiver to calculate, based on a braking command, a target braking force of the braking unit that transmits power of the electric motor to drive a friction material to brake the wheel; a transmission step using the receiver to transmit the command information including the target braking force calculated in the calculation step to a plurality of electric motor control devices; a command information reception step using the electric motor control devices to receive the command information transmitted in the transmission step; and a control step using the electric motor control devices to receive the command information transmitted in the transmission step. a detection step of detecting, using the motor control device, at least one of occurrence of wheel skid, occurrence of wheel mirroring, and change in the coefficient of friction between the wheel and the friction material or the contact surface of the rail, based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; and an adjustment step of adjusting, using the motor control device, the power supplied to the motor based on the command information in accordance with the detection result of the detection step.

[0027] According to this configuration, similar to the electromechanical brake control system described in (1) above, it is possible to improve the responsiveness when adjusting the power supplied to the electric motor based on the command information in accordance with the detection result.

[0028] (12) One aspect of the present invention is a brake control method using an electric motor control device that controls an electric motor of a braking unit for braking wheels of a vehicle, the brake control method including: a command information receiving step of receiving command information including a target braking force of the braking unit calculated based on a braking command; a power control step of controlling power supplied to the electric motor based on the command information; a detection step of detecting at least one of the occurrence of wheel skidding, the occurrence of wheel mirroring, and a change in the friction coefficient between the wheel and the friction material of the braking unit or the contact surface with the rail based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material of the braking unit against the contact surface of the wheel, the state of the rail on which the vehicle is traveling, and the state of the wheel; and an adjustment step of adjusting the power supplied to the electric motor based on the command information in accordance with the detection result of the detection step.

[0029] According to this configuration, similar to the electromechanical brake control system described in (1) above, it is possible to improve the responsiveness when adjusting the power supplied to the electric motor based on the command information in accordance with the detection result. [Effects of the Invention]

[0030] According to the present invention, it is possible to improve the responsiveness when adjusting the braking force in an electromechanical brake. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a diagram illustrating a schematic configuration of a railway vehicle equipped with an electromechanical brake control system according to an embodiment. [Figure 2] 1 is a block diagram illustrating an electromechanical brake control system according to an embodiment; [Figure 3] 4 is a flowchart showing an example of operation of the electromechanical brake control system according to the first embodiment. [Figure 4] 10 is a flowchart showing an example of operation of the electromechanical brake control system according to the second embodiment. [Figure 5]10 is a flowchart showing an example of operation of the electromechanical brake control system according to the third embodiment. [Figure 6] 13 is an example of a table used in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram showing a schematic configuration of a railway vehicle (hereinafter simply referred to as a vehicle) equipped with an electromechanical brake control system 1 according to an embodiment. Fig. 1 shows one side of the vehicle, and the other side (opposite side) is partially or entirely omitted from the illustration.

[0033] First, the vehicle will be described. One vehicle has two bogies (not shown), one at the front and one at the back. Each bogie has two axles. In FIG. 1, one bogie (not shown) has axles 80a and 80b, and the other bogie (not shown) has axles 80c and 80d. When axles 80a to 80d are not distinguished from one another, they are collectively referred to as axle 80. Each axle 80 has two wheels. In FIG. 1, axle 80a has wheels 81-1 and 81-2 (not shown). Axle 80b has wheels 81-3 and 81-4 (not shown). Axle 80c has wheels 81-5 and 81-6 (not shown). Axle 80d has wheels 81-7 and 81-8 (not shown). When there is no need to distinguish between the wheels 81-1 to 81-8, they are collectively referred to as wheels 81. In other words, one vehicle has two bogies, four axles 80, and eight wheels 81. Reference numeral 90 denotes a rail.

[0034] The vehicle is provided with a braking unit for braking each wheel 81. The braking unit includes an electric motor and a friction material driven by the power of the electric motor. In FIG. 1, wheel 81-1 is provided with braking unit 30-1 including electric motor 31-1 and friction material 32-1 driven by the power of electric motor 31-1. Wheel 81-2 (not shown) is provided with braking unit 30-2 (not shown) including electric motor 31-2 (not shown) and friction material 32-2 (not shown) driven by the power of electric motor 31-2. Wheel 81-3 is provided with braking unit 30-3 including electric motor 31-3 and friction material 32-3 driven by the power of electric motor 31-3. Wheel 81-4 (not shown) is provided with braking unit 30-4 (not shown) including electric motor 31-4 (not shown) and friction material 32-4 (not shown) driven by the power of electric motor 31-4. The same applies to wheels 81-5 to 81-8 (not shown). When braking units 30-1 to 30-8 are not distinguished from one another, they are collectively referred to as braking units 30. When electric motors 31-1 to 31-8 are not distinguished from one another, they are collectively referred to as electric motors 31. When friction materials 32-1 to 32-8 are not distinguished from one another, they are collectively referred to as friction materials 32. In other words, one vehicle has eight braking units 30 (brake units 30-1 to 30-8) corresponding to the eight wheels 81 (wheels 81-1 to 81-8), respectively.

[0035] The vehicle is provided with speed sensors (not shown). Specifically, the vehicle is provided with a speed sensor (referred to as speed sensor a) that measures the wheel speed of wheels 81 (wheels 81-1 and 81-2) on axle 80a, a speed sensor (referred to as speed sensor b) that measures the wheel speed of wheels 81 (wheels 81-3 and 81-4) on axle 80b, a speed sensor (referred to as speed sensor c) that measures the wheel speed of wheels 81 (wheels 81-5 and 81-6) on axle 80c, and a speed sensor (referred to as speed sensor d) that measures the wheel speed of wheels 81 (wheels 81-7 and 81-8) on axle 80d. In other words, one vehicle is provided with four speed sensors (speed sensors a to d) that correspond to the four axles 80 (axles 80a to 80d), respectively.

[0036] Speed ​​sensor a measures the wheel speed of wheel 81 on axle 80a based on the amount of rotation of axle 80a. Speed ​​sensor a may include a rotation sensor such as an encoder that outputs a pulse signal according to the rotational position of axle 80a. Speed ​​sensor a calculates the wheel speed of wheel 81 on axle 80a by multiplying the number of pulses per unit time of the pulse signal by a predetermined coefficient. The same applies to speed sensors b, c, and d.

[0037] The vehicle is provided with load sensors (not shown) that measure the pressing force (pressing force of the friction material 32 on the wheel 81) that presses the friction material 32 against the contact surface of the wheel 81. Specifically, the vehicle is provided with a load sensor that measures the pressing force of the friction material 32-1 on the wheel 81-1, a load sensor that measures the pressing force of the friction material 32-2 on the wheel 81-2, a load sensor that measures the pressing force of the friction material 32-3 on the wheel 81-3, a load sensor that measures the pressing force of the friction material 32-4 on the wheel 81-4, a load sensor that measures the pressing force of the friction material 32-5 on the wheel 81-5, a load sensor that measures the pressing force of the friction material 32-6 on the wheel 81-6, a load sensor that measures the pressing force of the friction material 32-7 on the wheel 81-7, and a load sensor that measures the pressing force of the friction material 32-8 on the wheel 81-8. That is, one vehicle is provided with eight load sensors corresponding to the eight friction materials 32 (friction material 32-1 to friction material 32-8), respectively.

[0038] The vehicle is provided with a camera (not shown) that captures images of the rails 90 on which the vehicle is traveling. One vehicle may be provided with one camera that captures images of the rails 90. One vehicle may be provided with eight cameras that capture images of the rails 90 corresponding to the eight braking units 30 (braking unit 30-1 to braking unit 30-8), respectively.

[0039] The vehicle may be provided with cameras (not shown) that capture images of the wheels 81. Specifically, the vehicle is provided with a camera that captures the contact surface of wheel 81-1 (the portion against which friction material 32-1 is pressed), a camera that captures the contact surface of wheel 81-2 (the portion against which friction material 32-2 is pressed), a camera that captures the contact surface of wheel 81-3 (the portion against which friction material 32-3 is pressed), a camera that captures the contact surface of wheel 81-4 (the portion against which friction material 32-4 is pressed), a camera that captures the contact surface of wheel 81-5 (the portion against which friction material 32-5 is pressed), a camera that captures the contact surface of wheel 81-6 (the portion against which friction material 32-6 is pressed), a camera that captures the contact surface of wheel 81-7 (the portion against which friction material 32-7 is pressed), and a camera that captures the contact surface of wheel 81-8 (the portion against which friction material 32-8 is pressed). That is, one vehicle may be provided with cameras that capture images of eight wheels 81 corresponding to the eight wheels 81 (wheels 81-1 to 81-8), respectively.

[0040] The vehicle is provided with temperature sensors (not shown) that measure the temperatures of the friction materials 32. Specifically, the vehicle is provided with a temperature sensor that measures the temperature of friction material 32-1, a temperature sensor that measures the temperature of friction material 32-2, a temperature sensor that measures the temperature of friction material 32-3, a temperature sensor that measures the temperature of friction material 32-1, a temperature sensor that measures the temperature of friction material 32-5, a temperature sensor that measures the temperature of friction material 32-6, a temperature sensor that measures the temperature of friction material 32-7, and a temperature sensor that measures the temperature of friction material 32-8. In other words, one vehicle is provided with eight temperature sensors that correspond to the eight friction materials 32 (friction materials 32-1 to 32-8), respectively.

[0041] As shown in FIG. 1, the electromechanical brake control system 1 includes a power receiver 10 and motor control units (motor control devices) 20-1 to 20-8. In FIG. 1, motor control units 20-1, 20-3, 20-5, and 20-7 on one side of the vehicle are shown with blocks and reference numerals, while motor control units 20-2, 20-4, 20-6, and 20-8 on the other side of the vehicle are shown with only reference numerals. The motor control unit 20-1 controls a braking unit 30-1 for braking a wheel 81-1. The motor control unit 20-2 controls a braking unit 30-2 (not shown) for braking a wheel 81-2 (not shown). The same applies to the motor control units 20-3 to 20-8. The motor control units 20-1 to 20-8 have the same configuration. When the motor control units 20-1 to 20-8 are not to be distinguished from one another, they are collectively referred to as the motor control unit 20. That is, one vehicle has one receiver 10 and eight motor control units 20 (motor control units 20-1 to 20-8) corresponding to the eight braking units 30 (brake units 30-1 to 30-8), respectively.

[0042] The receiver 10 receives a service braking command (also called a brake command) from an external device (for example, a vehicle control device (not shown)) via a metal wire. The service braking command is set according to the operating position of the brake handle operated by the driver. For example, depending on the operating position of the brake handle, a digital control signal of 1 notch to 7 notches (stages) is output to the receiver 10 as the service braking command.

[0043] When the receiver 10 receives a regular braking command, it calculates a target braking force (target brake force) based on the regular braking command, etc. The target braking force usually increases according to the number of notches. The receiver 10 transmits command information including the target braking force to the eight motor control units 20.

[0044] CAN communication is used between the receiver 10 and the motor control units 20. The receiver 10 is the master (control side) and the motor control units 20 are the slaves (non-control side). Information is transmitted from the receiver 10 to each motor control unit 20 in sequence at regular intervals (for example, 2.5 ms). Since there are eight motor control units 20, if the regular interval is 2.5 ms, for example, transmission to the eight motor control units 20 takes 20 ms (2.5 ms x 8). In other words, it takes 20 ms for the receiver 10 to finish transmitting one piece of command information to all of the motor control units 20.

[0045] The motor control unit 20 receives command information from the power receiver 10. When the motor control unit 20 receives the command information, it controls the braking unit 30. Specifically, the motor control unit 20 controls the power to be supplied to the motor 31 (power supplied to the motor 31 from a power source (not shown)) based on the command information. More specifically, the motor control unit 20 determines the power to be supplied to the motor 31 based on the command information, and controls the motor 31 with the determined power.

[0046] The motor control unit 20 receives an emergency braking command (also called an emergency brake command) from an external device (for example, a vehicle control device (not shown), a safety device (not shown), etc.) via a metal wire. Because the primary focus of emergency braking is to stop a moving train, the braking force applied by the emergency braking command is often set to be greater than or equal to the braking force applied by the normal braking command. When the motor control unit 20 receives an emergency braking command, it controls the braking unit 30 in the same way as when it receives command information. In other words, the motor control unit 20 determines the power to be supplied to the motor 31 based on the emergency braking command, and controls the motor 31 with the determined power.

[0047] When the motor control unit 20 receives the command information and the emergency braking command, the motor control unit 20 prioritizes the emergency braking command. That is, when the motor control unit 20 receives the command information and the emergency braking command, the motor control unit 20 controls the power to be supplied to the motor 31 based on the emergency braking command. That is, when the motor control unit 20 receives the command information and the emergency braking command, the motor control unit 20 determines the power to be supplied to the motor 31 based on the emergency braking command, and controls the motor 31 with the determined power.

[0048] The motor control unit 20 may adjust (increase or decrease) the power supplied to the motor 31 based on the command information (power determined based on the command information). The motor control unit 20 may adjust the power supplied to the motor 31 based on an emergency braking command (power determined based on the emergency braking command). Details will be described later.

[0049] When the electric motor control unit 20 adjusts the electric power (electric power determined based on command information, electric power determined based on an emergency braking command) supplied to the electric motor 31, the electric motor control unit 20 controls the electric motor 31 using the adjusted electric power (electric power after adjustment).

[0050] When the motor control unit 20 is adjusting the power supplied to the motor 31 (power determined based on command information, power determined based on an emergency braking command), it transmits notification information including a notification that the power is being adjusted to the receiver 10 via CAN communication.

[0051] The braking unit 30 brakes the wheel 81 under the control of the electric motor control unit 20. The electric motor 31 is driven (rotationally driven) under the control of the electric motor control unit 20. The power (power of rotational motion) by the electric motor 31 is converted into linear motion via a conversion mechanism (for example, a ball screw) or the like and transmitted to the friction material 32. The friction material 32 is pressed against the contact surface of the wheel 81 by the power transmitted from the electric motor 31. In other words, the braking unit 30 drives the electric motor 31 under the control of the electric motor control unit 20, and brakes the wheel 81 by the pressing force (braking force) that presses the friction material 32 against the wheel 81.

[0052] Fig. 2 is a block diagram that schematically shows an electromechanical brake control system 1 according to the embodiment. In the block diagram of Fig. 2, one electric motor control unit 20 is shown as a representative, but the other seven electric motor control units 20 are similar.

[0053] 2, the power receiver 10 includes a calculation unit 11, a command information transmission unit 12, a notification information reception unit 13, and a storage unit 14. The motor control unit 20 includes a command information reception unit 21, a power control unit 22, a detection unit 23, an adjustment unit 24, a notification information transmission unit 25, and an emergency command reception unit 26. The motor control unit 20 may also include a storage unit (not shown).

[0054] The calculation unit 11 receives a service braking command from an external device. The calculation unit 11 grasps the load amount (for example, AS pressure) as the number of passengers or the size of cargo from a load compensation device (load sensor, not shown) (receives a value indicating the load amount). The calculation unit 11 queries a VVVF control device (not shown) to grasp the braking force due to regenerative braking (receives a value indicating the braking force due to regenerative braking). Based on the service braking command, the load amount, and the braking force of the regenerative braking, the calculation unit 11 calculates a target braking force (target braking force of the braking unit 30) for transmitting the power of the electric motor 31 to drive the friction material 32 and brake the wheels 81.

[0055] The command information transmitting unit 12 transmits command information including the target braking force calculated by the calculating unit 11 to the plurality of electric motor control units 20 via CAN communication.

[0056] The notification information receiver 13 receives notification information including a notification that power is being adjusted from the motor control unit 20. As described above, when the motor control unit 20 is adjusting the power supplied to the motor 31, it transmits the notification information to the power receiver 10 via CAN communication. Note that the command information transmitter 12 and the notification information receiver 13 may be the same component (device).

[0057] The storage unit 14 stores the notification information received by the notification information receiving unit 13. For example, the storage unit 14 may store the notification information in association with time information (reception time).

[0058] The command information receiving unit 21 receives command information by CAN communication from the receiver 10. The emergency command receiving unit 26 receives an emergency braking command (emergency command) from an external device by metal wire.

[0059] When the command information receiving unit 21 receives command information, the power control unit 22 controls the power to be supplied to the electric motor 31 based on the command information. Specifically, the power control unit 22 determines the power to be supplied to the electric motor 31 based on the command information, and controls the electric motor 31 using the determined power. The power control unit 22 may calculate and determine the power to be supplied to the electric motor 31 based on the command information using a target braking force included in the command information and a predetermined coefficient. The predetermined coefficient may be a value obtained by multiplying a friction coefficient set as a reference value (i.e., a standard friction coefficient between the contact surface of the friction material 32 and the wheel 81) by a constant.

[0060] When the emergency command receiving unit 26 receives an emergency braking command, the power control unit 22 controls the power supplied to the electric motor 31 based on the emergency braking command. Specifically, the power control unit 22 determines the power to be supplied to the electric motor 31 based on the emergency braking command, and controls the electric motor 31 using the determined power. The power control unit 22 may calculate and determine the power to be supplied to the electric motor 31 based on the emergency braking command using the braking force due to the emergency braking command and a predetermined coefficient. The predetermined coefficient may be a value obtained by multiplying a friction coefficient set as a reference value (i.e., a standard friction coefficient between the contact surface of the friction material 32 and the wheel 81) by a constant.

[0061] When the command information receiving unit 21 receives command information and the emergency command receiving unit 26 receives an emergency braking command, the power control unit 22 prioritizes power control based on the emergency braking command. That is, in the above-mentioned case, the power control unit 22 determines the power to be supplied to the electric motor 31 based on the emergency braking command, and controls the electric motor 31 with the determined power.

[0062] When the power supplied to the electric motor 31 (power determined based on command information, power determined based on an emergency braking command) is adjusted by the adjustment unit 24, the power control unit 22 controls the electric motor 31 with the adjusted power.

[0063] The detection unit 23 detects at least one of the occurrence of wheel skidding of the wheel 81, the occurrence of mirror polishing of the wheel 81, and a change in the coefficient of friction between the friction material 32 and the contact surface of the wheel 81, based on at least one measurement result of the wheel speed of the wheel 81, the pressing force pressing the friction material 32 against the contact surface of the wheel 81, the state of the rail 90 on which the vehicle is traveling, and the state of the wheel 81. In other words, the detection unit 23 determines one or more of the occurrence of wheel skidding of the wheel 81, the occurrence of mirror polishing of the wheel 81, and the presence or absence of a change in the coefficient of friction between the friction material 32 and the contact surface of the wheel 81, based on the above-mentioned measurement results.

[0064] The detection unit 23 acquires the measurement results of the wheel speeds measured by the four speed sensors (receives speed signals and speed information). The detection unit 23 may acquire the measurement results of the wheel speeds from the speed sensors, or may acquire the measurement results of the wheel speeds from other electric motor control units 20. For example, the detection unit 23 acquires the measurement results of the speed sensors that measure the wheel speeds of the wheels 81 to be braked from the speed sensors, and acquires the measurement results of the speed sensors that measure the wheel speeds of the wheels 81 other than the wheel 81 to be braked from other electric motor control units 20. The following description will be given taking the detection units 23 of the electric motor control units 20-1 to 20-4 as an example, but the same applies to the detection units 23 of the electric motor control units 20-5 to 20-8.

[0065] The detection unit 23 of the motor control unit 20-1 acquires the wheel speed measurement results (measurement results of the wheel speeds of wheels 81-1 and 81-2) by the speed sensor a from the speed sensor a. The detection unit 23 of the motor control unit 20-1 acquires (acquires via CAN communication) the wheel speed measurement results (measurement results of the wheel speeds of wheels 81-3 and 81-4) by the speed sensor b from the motor control unit 20-3 (or the motor control unit 20-4). The detection unit 23 of the motor control unit 20-1 acquires (acquires via CAN communication) the wheel speed measurement results (measurement results of the wheel speeds of wheels 81-5 and 81-6) by the speed sensor c from the motor control unit 20-5 (or the motor control unit 20-6). The detection unit 23 of the motor control unit 20-1 acquires (by CAN communication) the measurement results of the wheel speeds (measurement results of the wheel speeds of the wheels 81-7 and 81-8) by the speed sensor d from the motor control unit 20-7 (or the motor control unit 20-8). The same applies to the detection unit 23 of the motor control unit 20-2.

[0066] The detection unit 23 of the motor control unit 20-3 acquires (via CAN communication) the wheel speed measurement results obtained by the speed sensor a (the wheel speed measurement results of wheels 81-1 and 81-2) from the motor control unit 20-1 (or the motor control unit 20-2). The detection unit 23 of the motor control unit 20-3 acquires (via CAN communication) the wheel speed measurement results obtained by the speed sensor b (the wheel speed measurement results of wheels 81-3 and 81-4) from the speed sensor b. The detection unit 23 of the motor control unit 20-3 acquires (via CAN communication) the wheel speed measurement results obtained by the speed sensor c (the wheel speed measurement results of wheels 81-5 and 81-6) from the motor control unit 20-5 (or the motor control unit 20-6). The detection unit 23 of the motor control unit 20-3 acquires (by CAN communication) the measurement results of the wheel speeds (measurement results of the wheel speeds of the wheels 81-7 and 81-8) by the speed sensor d from the motor control unit 20-7 (or the motor control unit 20-8). The same applies to the detection unit 23 of the motor control unit 20-4.

[0067] The detection unit 23 acquires the measurement result of the pressing force applied to the wheel 81 by the friction material 32 measured by the load sensor (receives the pressing force signal). For example, the detection unit 23 of the motor control unit 20-1 acquires the measurement result from a load sensor that measures the pressing force applied to the wheel 81-1 by the friction material 32-1. The detection unit 23 of the motor control unit 20-2 acquires the measurement result from a load sensor that measures the pressing force applied to the wheel 81-2 by the friction material 32-2. The same applies to the detection units 23 of the motor control units 20-3 to 20-8. In other words, the detection unit 23 acquires the measurement result from one load sensor that measures the pressing force applied to the wheel 81 to be braked (the pressing force applied by the friction material 32 corresponding to the wheel 81 to be braked).

[0068] The detection unit 23 acquires (receives image data from) a camera that captures an image of the rail 90 on which the vehicle is traveling, and measures the condition of the rail 90 (whether it is wet, etc.). The detection unit 23 may acquire the image from a camera, or may acquire the image from another motor control unit 20 (acquired via CAN communication).

[0069] The detection unit 23 may measure (determine) the state of the rails 90 by image processing (image analysis). The detection unit 23 may determine whether the rails 90 are wet using a trained model. The trained model described above may be a trained model that is machine-learned using captured images of the rails 90 that are wet while the vehicle is traveling and captured images of the rails 90 that are not wet while the vehicle is traveling.

[0070] The detection unit 23 may acquire an image (receive image data) from a camera that captures an image of the wheel 81 and measure the state of the wheel 81 (whether it is mirror-finished, wet, etc.). The detection unit 23 of the motor control unit 20-1 acquires an image from a camera that captures an image of the contact surface of the wheel 81-1 with the friction material 32-1. The detection unit 23 of the motor control unit 20-2 acquires an image from a camera that captures an image of the contact surface of the wheel 81-2 with the friction material 32-2. The same applies to the detection units 23 of the motor control units 20-3 to 20-8. In other words, the detection unit 23 acquires an image from one camera that captures an image of the contact surface of the wheel 81 to be braked.

[0071] The detection unit 23 may measure (determine) the state of the wheel 81 by image processing (image analysis). The detection unit 23 may determine whether the wheel 81 has a mirror finish using a trained model. The trained model described above may be a trained model that has been machine-learned using captured images of the wheel 81 that has a mirror finish while the vehicle is moving and captured images of the wheel 81 that does not have a mirror finish while the vehicle is moving. The detection unit 23 may determine whether the wheel 81 is wet using a trained model. The trained model described above may be a trained model that has been machine-learned using captured images of the wheel 81 that has a wet finish while the vehicle is moving and captured images of the wheel 81 that does not have a wet finish while the vehicle is moving.

[0072] The detection unit 23 acquires the measurement results of the temperature of the friction material 32 measured by the temperature sensor (receives a temperature signal). For example, the detection unit 23 of the motor control unit 20-1 acquires the measurement results from a temperature sensor that measures the temperature of the friction material 32-1. The detection unit 23 of the motor control unit 20-2 acquires the measurement results from a temperature sensor that measures the temperature of the friction material 32-2. The same applies to the detection units 23 of the motor control units 20-3 to 20-8. In other words, the detection unit 23 acquires the measurement results from one temperature sensor that measures the temperature of the friction material 32 corresponding to the wheel 81 to be braked.

[0073] The adjustment unit 24 adjusts (increases or decreases) the power supplied to the electric motor 31 based on the command information (power determined based on the command information) or the power supplied to the electric motor 31 based on the emergency braking command (power determined based on the emergency braking command) in accordance with the detection result of the detection unit 23. The adjustment unit 24 of the electric motor control unit 20-1 adjusts the power supplied to the electric motor 31-1 (power determined based on the command information or the emergency braking command) in accordance with the detection result of the detection unit 23 of the electric motor control unit 20-1. The adjustment unit 24 of the electric motor control unit 20-2 adjusts the power supplied to the electric motor 31-2 (power determined based on the command information or the emergency braking command) in accordance with the detection result of the detection unit 23 of the electric motor control unit 20-2. The same applies to the adjustment units 24 of the electric motor control units 20-3 to 20-8. Specific details of the adjustment by the adjustment unit 24 will be described later.

[0074] When the adjustment unit 24 is adjusting the power supplied to the electric motor 31, the notification information transmission unit 25 transmits, to the electric power receiver 10, notification information including a notification that the power is being adjusted. When the adjustment unit 24 is adjusting the power supplied to the electric motor 31 based on command information (power determined based on the command information), the notification information transmission unit 25 may transmit, to the electric power receiver 10, notification information including a notification that the power determined based on the command information is being adjusted. When the adjustment unit 24 is adjusting the power supplied to the electric motor 31 based on an emergency braking command (power determined based on the emergency braking command), the notification information transmission unit 25 may transmit, to the electric power receiver 10, notification information including a notification that the power determined based on the emergency braking command is being adjusted. Note that the command information receiving unit 21 and the notification information transmission unit 25 may be the same component.

[0075] The notification information transmitter 25 may transmit notification information including identification information that can identify the motor control unit 20 to the meter receiver 10. For example, the notification information transmitter 25 of the motor control unit 20-1 may transmit notification information including device identification information of the motor control unit (motor control device) 20-1 to the meter receiver 10. The notification information transmitter 25 of the motor control unit 20-2 may transmit notification information including device identification information of the motor control unit (motor control device) 20-2 to the meter receiver 10. The same applies to the notification information transmitters 25 of the motor control units 20-3 to 20-8.

[0076] The notification information transmitter 25 may transmit notification information including the result of the power adjustment (e.g., the power before adjustment, the amount of adjustment, etc.) to the power receiver 10. For example, when the adjustment unit 24 of the motor control unit 20-1 adjusts the power supplied to the motor 31-1, the notification information transmitter 25 of the motor control unit 20-1 may transmit notification information including the result of the power adjustment by the adjustment unit 24 of the motor control unit 20-1 to the power receiver 10. When the adjustment unit 24 of the motor control unit 20-2 adjusts the power supplied to the motor 31-2, the notification information transmitter 25 of the motor control unit 20-2 may transmit notification information including the result of the power adjustment by the adjustment unit 24 of the motor control unit 20-2 to the power receiver 10. The same applies to the notification information transmitters 25 of the motor control units 20-3 to 20-8.

[0077] [First Example] As a first embodiment, an operation for adjusting the power determined based on command information when skidding of the wheels 81 occurs will be described.

[0078] Fig. 3 is a flowchart showing an example of operation according to the first embodiment of the electromechanical brake control system 1. In the flowchart of Fig. 3 (the same applies to the flowcharts of Figs. 4 and 5), the left side shows the operation of the charge receiver 10, and the right side shows the operation of the electric motor control unit 20. The flowchart of Fig. 3 (the same applies to the flowcharts of Figs. 4 and 5) shows the operation of one electric motor control unit 20 as a representative. The flowchart of Fig. 3 (the same applies to the flowcharts of Figs. 4 and 5) starts when the charge receiver 10 receives a service braking command from an external device while the vehicle is traveling.

[0079] The calculation unit 11 calculates a target braking force for the braking unit 30 (step S1). The command information transmission unit 12 transmits command information including the target braking force calculated in step S1 (step S2).

[0080] The command information receiving unit 21 receives the command information including the target braking force (step S3). The power control unit 22 determines the power to be supplied to the electric motor 31 based on the command information received in step S3 (step S4).

[0081] The detection unit 23 acquires measurement results of multiple wheel speeds (step S5). The detection unit 23 determines whether or not skidding of the wheel 81 has occurred (detects the occurrence of skidding) based on the measurement results (multiple wheel speeds) acquired in step S5 (step S6). Specifically, the detection unit 23 determines that skidding of the wheel 81 to be braked has not occurred if the speed difference between the wheel speed of the wheel 81 to be braked (also referred to as the target axle speed) and the wheel speed of the comparison reference (also referred to as the reference axle speed or vehicle speed) is equal to or less than a predetermined threshold, and determines that skidding of the wheel 81 to be braked has occurred if the speed difference exceeds the predetermined threshold. In other words, the detection unit 23 determines that skidding of the wheel 81 to be braked has occurred if the wheel speed of the wheel 81 to be braked becomes slower than the wheel speed of the comparison reference by a value exceeding the predetermined threshold.

[0082] The comparison reference wheel speed may be the wheel speed of a wheel 81 on an axle 80 (for example, another axle 80 of the same bogie) different from the axle 80 on which the wheel 81 to be braked is located.

[0083] As one example, the detection unit 23 of the electric motor control unit 20-1 determines that wheel 81-1 is not sliding if the speed difference between the wheel speed of wheel 81-1 to be braked and the wheel speed of the comparison reference (wheel speed of wheel 81-3 (or wheel 81-4)) is equal to or smaller than a predetermined threshold, and determines that wheel 81-1 is sliding if the speed difference exceeds the predetermined threshold. As another example, the detection unit 23 of the electric motor control unit 20-7 determines that wheel 81-7 is not sliding if the speed difference between the wheel speed of wheel 81-7 to be braked and the wheel speed of the comparison reference (wheel speed of wheel 81-5 (or wheel 81-6)) is equal to or smaller than a predetermined threshold, and determines that wheel 81-7 is sliding if the speed difference exceeds the predetermined threshold.

[0084] The comparison reference wheel speed may be the maximum value (or average value) of the wheel speeds of wheels 81 on a plurality of axles 80 (for example, other axles 80 of the same vehicle) different from the axle 80 on which the wheel 81 to be braked is located.

[0085] As one example, the detection unit 23 of the electric motor control unit 20-1 determines that wheel 81-1 is not sliding if the speed difference between the wheel speed of wheel 81-1 to be braked and the comparison reference wheel speed (the maximum value (or average value) of the wheel speeds of wheels 81-3 to 81-8) is equal to or smaller than a predetermined threshold, and determines that wheel 81-1 is sliding if the speed difference exceeds the predetermined threshold. As another example, the detection unit 23 of the electric motor control unit 20-7 determines that wheel 81-7 is not sliding if the speed difference between the wheel speed of wheel 81-7 to be braked and the comparison reference wheel speed (the maximum value (or average value) of the wheel speeds of wheels 81-1 to 81-6) is equal to or smaller than a predetermined threshold, and determines that wheel 81-7 is sliding if the speed difference exceeds the predetermined threshold.

[0086] When the detection unit 23 determines that sliding of the wheel 81 has occurred, it notifies the adjustment unit 24 of the determination result that sliding of the wheel 81 has occurred. When the detection unit 23 determines that sliding of the wheel 81 has not occurred, it may notify the adjustment unit 24 of the determination result that sliding of the wheel 81 has not occurred.

[0087] If the detection unit 23 determines that wheel slippage is not occurring (step S7: NO), the power control unit 22 controls the electric motor 31 with the power determined in step S4 (step S8), and then this flowchart ends.

[0088] If the detection unit 23 determines that wheel skidding is occurring (step S7: YES), the adjustment unit 24 adjusts the power determined by the power control unit 22 in step S4 to a lower power (step S9).

[0089] In other words, if the detection unit 23 has not detected the occurrence of wheel slide of the wheel 81 (step S7: NO), the adjustment unit 24 maintains the power determined by the power control unit 22 in step S4 and does not adjust it. Specifically, if the detection unit 23 has not notified the adjustment unit 24 of the determination result that wheel slide is occurring (or if the adjustment unit 24 has not notified the adjustment unit 24 of the determination result that wheel slide of the wheel 81 is occurring), the adjustment unit 24 maintains the power determined by the power control unit 22 in step S4 and does not adjust it. On the other hand, if the detection unit 23 has detected the occurrence of wheel slide of the wheel 81 (step S7: YES), the adjustment unit 24 reduces the power determined by the power control unit 22 in step S4. Specifically, if the detection unit 23 has notified the adjustment unit 24 of the determination result that wheel slide is occurring, the adjustment unit 24 reduces the power determined by the power control unit 22 in step S4.

[0090] The method of adjusting the power by the adjustment unit 24 is not particularly limited. The adjustment unit 24 may reduce the original power (the power determined by the power control unit 22) by a predetermined rate. For example, the adjustment unit 24 may set the adjusted power to 20% to 80% of the original power. The adjustment unit 24 may reduce the original power by specifying the adjustment amount according to a predetermined pattern in which the amount of power reduction is set based on one or more of the original power, the degree of slide (speed exceeding a threshold), the state of the rails 90, the vehicle speed, the temperature, and the humidity. The adjustment unit 24 may calculate the adjustment amount using a predetermined formula that calculates the amount of power reduction using one or more of the original power, the degree of slide, the state of the rails 90, the vehicle speed, the temperature, and the humidity as variables, and reduce the original power. The temperature and humidity are acquired by, for example, a sensor (not shown). Note that although the case of reducing the power has been described, the same applies to the case of increasing the power.

[0091] The power control unit 22 controls the electric motor 31 with the power (reduced power) after adjustment in step S9 (step S10). The notification information transmission unit 25 transmits notification information including a notification that the power determined based on the command information is being adjusted to the power receiver 10 (step S11).

[0092] The notification information receiving unit 13 determines whether or not there is notification information from the motor control unit 20 (step S12). If there is notification information (step S12: YES), the notification information receiving unit 13 receives the notification information (step S13). The storage unit 14 stores the notification information received in step S13 (step S14). Then, this flowchart ends. If there is no notification information (step S12: NO), this flowchart ends.

[0093] As described above, as shown in the flowchart of Fig. 3, the electric motor control unit 20 determines whether or not the vehicle is in a sliding state, and if it determines that the vehicle is in a sliding state, it adjusts (reduces) the power determined based on the command information in order to eliminate the sliding state (to achieve an adhesive state).If the electric motor control unit 20 determines that the vehicle is not in a sliding state after determining that the vehicle is in a sliding state (if the sliding state is eliminated), it stops adjusting (reducing) the power determined based on the command information (maintains the power determined based on the command information).

[0094] In the first embodiment, the operation of adjusting the power determined based on the command information has been described, but the same applies to the operation of adjusting the power determined based on the emergency braking command. That is, the motor control unit 20 determines whether or not the vehicle is in a sliding state, and if it determines that the vehicle is in a sliding state, it adjusts (reduces) the power determined based on the emergency braking command to eliminate the sliding state. If the motor control unit 20 determines that the vehicle is not in a sliding state after determining that the vehicle is in a sliding state, it stops adjusting (reducing) the power determined based on the emergency braking command (maintains the power determined based on the emergency braking command).

[0095] [Second Example] As a second embodiment, an operation for adjusting the power determined based on command information when the wheels 81 become mirror-finished will be described.

[0096] Fig. 4 is a flowchart showing an example of operation according to the second embodiment of the electromechanical brake control system 1. The operations of steps S21, S22, S23, S24, S28, S31, S32, S33, and S34 in the flowchart of Fig. 4 are similar to the operations of steps S1, S2, S3, S4, S8, S11, S12, S13, and S14 in the flowchart of Fig. 3, and therefore, a part or all of the description thereof will be omitted.

[0097] The detection unit 23 acquires the measurement result of the pressing force applied to the wheel 81 by the friction material 32 (step S25). Specifically, the detection unit 23 acquires the measurement result of the pressing force from one load sensor that measures the pressing force applied to the wheel 81 that is the target of braking.

[0098] The detection unit 23 determines whether or not mirror finish has occurred on the wheel 81 based on the measurement result (pressing force) acquired in step S25 (detects the occurrence of mirror finish) (step S26). For example, the detection unit 23 determines whether or not mirror finish has occurred as in the following steps S26A to S26C.

[0099] Step S26A: The detection unit 23 calculates a state update value for updating the wheel state value based on the pressing force. The wheel state value is a value that quantifies the state of the contact surface between the friction material 32 and the wheel 81. The smaller the wheel state value, the smaller the friction coefficient of the contact surface between the friction material 32 and the wheel 81. For example, when the pressing force is equal to or greater than a predetermined first threshold, the detection unit 23 multiplies the pressing force by a first coefficient that is 0 or greater and sets the resulting value as the state update value. When the pressing force is less than the predetermined first threshold, the detection unit 23 multiplies the pressing force by a second coefficient that is 0 or less and sets the resulting value as the state update value. Step S26B: The detection unit 23 updates the wheel state value using the state update value. For example, the detection unit 23 sets the new wheel state value to a value obtained by multiplying the previous wheel state value by a forgetting factor (a value between 0 and 1) and adding the state update value to the resultant value. Step S26C: The detection unit 23 determines whether or not mirror finish has occurred based on the new wheel state value. For example, if the new wheel state value is equal to or greater than a predetermined second threshold, the detection unit 23 determines that mirror finish has not occurred. If the wheel state value is less than the predetermined second threshold, the detection unit 23 determines that mirror finish has occurred.

[0100] The first threshold, the second threshold, the first coefficient, the second coefficient, and the forgetting coefficient are determined based on actual measurement values, simulation values, and the like.

[0101] If the detection unit 23 determines that the wheels have not become mirror-finished (step S27: NO), the power control unit 22 controls the electric motor 31 with the electric power determined in step S24 (step S28), and then this flowchart ends.

[0102] If the detection unit 23 determines that wheel slippage is occurring (step S27: YES), the adjustment unit 24 adjusts the power determined by the power control unit 22 in step S24 to a higher power (step S29). Naturally, the adjustment unit 24 adjusts the pressing force due to the adjusted power so that it is equal to or greater than the first threshold value.

[0103] The power control unit 22 controls the electric motor 31 with the power after adjustment in step S29 (the increased power) (step S30). The notification information sending unit 25 sends notification information including a notification that the power determined based on the command information is being adjusted to the receiver 10 (step S31). The notification information receiving unit 13 receives the notification information from the electric motor control unit 20 (step S32). The memory unit 14 stores the notification information received in step S32 (step S33). Then, this flowchart ends.

[0104] As described above, as shown in the flowchart of Fig. 4, the electric motor control unit 20 determines whether the wheel 81 is specular, and if it determines that the wheel 81 is specular, it adjusts (increases) the electric power determined based on the command information in order to eliminate the specular finish (to roughen the wheel 81). If the electric motor control unit 20 determines that the wheel 81 is not specular after determining that the wheel 81 is specular (if the specular finish has been eliminated), it stops adjusting (increasing) the electric power determined based on the command information (maintains the electric power determined based on the command information).

[0105] In the second embodiment, the motor control unit 20 determines whether or not the wheel 81 has become mirror-finished based on the pressing force that presses the friction material 32 against the contact surface of the wheel 81, but the motor control unit 20 may also determine whether or not the wheel 81 has become mirror-finished based on a captured image of the wheel 81. In other words, the motor control unit 20 may detect the occurrence of mirror-finishing based on an image of the wheel tread (the state of the wheel).

[0106] [Third Example] As a third embodiment, an operation for adjusting the power determined based on command information when the friction coefficient between the friction material 32 and the contact surface of the wheel 81 changes will be described.

[0107] Fig. 5 is a flowchart showing an example of operation according to a third embodiment of the electromechanical brake control system 1. Fig. 6 is an example of a table used in the third embodiment. The operations of steps S41, S42, S43, S44, S48, S51, S52, S53, and S54 in the flowchart of Fig. 5 are similar to the operations of steps S1, S2, S3, S4, S8, S11, S12, S13, and S14 in the flowchart of Fig. 3, and therefore, some or all of the description thereof will be omitted.

[0108] The detection unit 23 acquires the measurement results of the temperature of the friction material 32 and the measurement results of the wheel speed of the wheel 81 (step S45). Specifically, the detection unit 23 acquires the temperature measurement results from one temperature sensor that measures the temperature of the friction material 32 corresponding to the wheel 81 to be braked. The detection unit 23 acquires the temperature measurement results from one speed sensor that measures the wheel speed of the wheel 81 to be braked.

[0109] The detection unit 23 determines whether or not there has been a change in the friction coefficient between the friction material 32 and the contact surface of the wheel 81 based on the measurement results (temperature, wheel speed) acquired in step S45 (detects a change in the friction coefficient) (step S46). For example, the detection unit 23 identifies the current friction coefficient using a friction coefficient identification table such as that shown in FIG.

[0110] The friction coefficient specification table is a table for specifying the friction coefficient between the friction material 32 and the contact surface of the wheel 81 based on the temperature of the friction material 32 and the wheel speed of the wheel 81. In the friction coefficient specification table, the temperature T of the friction material 32 is <T2<…<T N In the friction coefficient specification table, the wheel speed V is V1 <V2<…<V M When the temperature T of the friction material 32 is constant, the friction coefficient μ decreases as the wheel speed V increases. X With respect to μ X1 >μ X2 …>μ XM When the wheel speed V is constant, the friction coefficient μ becomes smaller as the temperature T of the friction material 32 increases. X In μ1X >μ 2X >…>μ NX is.

[0111] The friction coefficient specification table is stored, for example, in a storage unit (not shown) of the electric motor control unit 20. The values ​​in the friction coefficient specification table are determined based on actual measurement values, simulation values, and the like.

[0112] The detection unit 23 determines that the friction coefficient has not changed if the difference between the latest friction coefficient identified by the friction coefficient identification table and the reference friction coefficient (e.g., the standard friction coefficient between the friction material 32 and the contact surface of the wheel 81) is less than a predetermined threshold value.

[0113] If the detection unit 23 determines that the friction coefficient has not changed (step S47: NO), the power control unit 22 controls the electric motor 31 with the power determined in step S44 (step S48), and then this flowchart ends.

[0114] If the detection unit 23 determines that the friction coefficient has changed (step S47: YES), the adjustment unit 24 adjusts the power determined by the power control unit 22 in step S44 (step S49). Specifically, if the friction coefficient has increased (i.e., if the latest friction coefficient is greater than the reference friction coefficient by a predetermined threshold or more), the adjustment unit 24 adjusts the power determined by the power control unit 22 in step S44 to be lower (step S49). If the friction coefficient has decreased (i.e., if the latest friction coefficient is smaller than the reference friction coefficient by a predetermined threshold or more), the adjustment unit 24 adjusts the power determined by the power control unit 22 in step S44 to be higher (step S49).

[0115] The electric power to be supplied to the electric motor 31 based on the command information can be calculated by the following equation 1 using the target braking force included in the command information, the coefficient of friction between the contact surface of the friction material 32 and the wheel 81, and a constant. By the processing of step S49, the electric power according to the target braking force can be suitably adjusted in accordance with changes in the coefficient of friction.

[0116] Power = target braking force / (friction coefficient x constant)...(1)

[0117] The power control unit 22 controls the electric motor 31 with the electric power adjusted in step S49 (step S50). The notification information sending unit 25 sends notification information including a notification that the electric power determined based on the command information is being adjusted to the receiver 10 (step S51). The notification information receiving unit 13 receives the notification information from the electric motor control unit 20 (step S52). The memory unit 14 stores the notification information received in step S52 (step S53). Then, this flowchart ends.

[0118] As described above, as shown in the flowchart of FIG. 5, the motor control unit 20 determines whether the friction coefficient between the friction material 32 and the contact surface of the wheel 81 has changed, and if it determines that the friction coefficient has changed, adjusts the power determined based on the command information.

[0119] In the third embodiment, an example was described in which the friction coefficient between the friction material 32 and the contact surface of the wheel 81 was determined from the temperature of the friction material 32 and the wheel speed of the wheel 81. However, the friction coefficient between the friction material 32 and the contact surface of the wheel 81 may also be calculated using a formula that calculates the friction coefficient between the friction material 32 and the contact surface of the wheel 81 from the temperature of the friction material 32 and the wheel speed of the wheel 81.

[0120] In the third embodiment, the motor control unit 20 determines whether or not there has been a change in the coefficient of friction between the contact surface of the friction material 32 and the wheel 81 based on the temperature of the friction material 32 and the wheel speed of the wheel 81. However, the motor control unit 20 may also determine whether or not there has been a change in the coefficient of friction between the contact surface of the friction material 32 and the wheel 81 based on a captured image of the wheel 81. For example, the motor control unit 20 may determine that the coefficient of friction between the contact surface of the friction material 32 and the wheel 81 has decreased when it is determined based on the captured image of the wheel 81 that the wheel 81 has changed from a dry state to a wet state, and may determine that the coefficient of friction between the contact surface of the friction material 32 and the wheel 81 has increased when it is determined based on the captured image of the wheel 81 that the wheel 81 has changed from a wet state to a dry state.

[0121] The motor control unit 20 may determine whether or not there is a change in the coefficient of friction between the friction material 32 and the contact surface of the wheel 81 based on the captured image of the rail 90. For example, when the motor control unit 20 determines that the rail 90 has changed from a dry state to a wet state based on the captured image of the rail 90, it may determine that the coefficient of friction between the friction material 32 and the contact surface of the wheel 81 has decreased, and when the motor control unit 20 determines that the rail 90 has changed from a wet state to a dry state based on the captured image of the rail 90, it may determine that the coefficient of friction between the friction material 32 and the contact surface of the wheel 81 has increased. Note that if the rail 90 is wet, it is inferred that the wheel 81 is also wet, and if the rail 90 is dry, it is inferred that the wheel 81 is also dry.

[0122] The motor control unit 20 may determine whether or not there is a change in the coefficient of friction between the contact surface of the rail 90 and the wheel 81 based on the captured image of the rail 90. For example, when the motor control unit 20 determines that the rail 90 has changed from a dry state to a wet state based on the captured image of the rail 90, it may determine that the coefficient of friction between the contact surface of the rail 90 and the wheel 81 has decreased, and when the motor control unit 20 determines that the rail 90 has changed from a wet state to a dry state based on the captured image of the rail 90, it may determine that the coefficient of friction between the contact surface of the rail 90 and the wheel 81 has increased. Note that when the coefficient of friction of the rail 90 is small, skidding is more likely to occur.

[0123] In the third embodiment, the operation of adjusting the power determined based on the command information has been described, but the same applies to the operation of adjusting the power determined based on the emergency braking command. That is, the motor control unit 20 determines whether the coefficient of friction between the friction material 32 and the contact surface of the wheel 81 has changed, and if it determines that there has been a change, adjusts the power determined based on the emergency braking command depending on whether the coefficient of friction has increased or decreased.

[0124] Although the operations have been explained individually as the first to third embodiments, these operations can be implemented in combination.

[0125] For example, the motor control unit 20 reduces the power supplied to the motor 31 when wheel 81 is skidding (first embodiment), and increases the power supplied to the motor 31 when wheel 81 is becoming mirror-finished (second embodiment). However, when wheel 81 is skidding and wheel 81 is becoming mirror-finished, priority may be given to wheel 81 skidding, and the power supplied to the motor 31 may be reduced.

[0126] The motor control unit 20 reduces the power supplied to the motor 31 when wheel 81 is slipping (first embodiment), and increases the power supplied to the motor 31 when the coefficient of friction between the friction material 32 and the contact surface of the wheel 81 is decreasing (third embodiment). However, when wheel 81 is slipping and the coefficient of friction is decreasing, priority may be given to the slipping of the wheel 81 and the power supplied to the motor 31 may be reduced.

[0127] The electromechanical brake control system 1 according to the embodiment has been described above. According to the electromechanical brake control system 1, the electric motor control unit 20 detects at least one of the occurrence of wheel skidding of the wheel 81, the occurrence of mirror-finishing of the wheel 81, and the coefficient of friction between the friction material 32 and the contact surface of the wheel 81, and adjusts the power supplied to the electric motor 31 (power determined based on the command information, power determined based on the emergency braking command) according to the detection result, thereby shortening the time required to adjust the power supplied to the electric motor 31 according to the detection result. In other words, the electromechanical brake control system 1 can improve responsiveness when adjusting the power supplied to the electric motor 31 according to the detection result (in other words, responsiveness to the occurrence of wheel skidding of the wheel 81, the occurrence of mirror-finishing of the wheel 81, and changes in the coefficient of friction between the friction material 32 and the contact surface of the wheel 81).

[0128] For example, as described in the first embodiment, the motor control unit 20, not the receiver 10, determines whether the vehicle is in a sliding state, and if it determines that the vehicle is in a sliding state, adjusts the power determined based on the command information. If the motor control unit 20 determines that the vehicle is not in a sliding state after determining that the vehicle is in a sliding state, it stops adjusting the power determined based on the command information (maintains the power determined based on the command information). Therefore, responsiveness when adjusting power in response to the occurrence of sliding or the elimination of sliding can be improved. For example, higher responsiveness can be achieved compared to when adjusting power in response to the occurrence of sliding or the elimination of sliding by control of the receiver 10. In other words, since it takes 20 ms for the receiver 10 to complete transmitting one command information to all motor control units 20, a time lag occurs in control by the receiver 10. However, in the first embodiment, control is completed on the motor control unit 20 side without going through the receiver 20, so there is no time lag and high responsiveness is achieved. Similarly, the responsiveness when adjusting power can be improved in situations where power is adjusted in response to the mirror finish of wheel 81 as described in the second embodiment, and in situations where power is adjusted in response to changes in the friction coefficient as described in the third embodiment.

[0129] Furthermore, the wheel speed is input to the motor control unit 20 rather than to the receiver 10, meaning that the wiring for the speed sensor does not need to be connected to the receiver 10, thereby shortening the wiring distance.

[0130] Modifications will now be described. The following modifications 1 to 5 may be combined as appropriate. [Variation 1] Even when the electric motor control unit 20 does not detect the occurrence of skidding of the wheel 81, the electric motor control unit 20 may adjust the power supplied to the electric motor 31 in relation to the control of the other electric motor control units 20. For example, when the electric motor control unit 20 (e.g., electric motor control unit 20-1) does not detect the occurrence of skidding of the wheel 81 (e.g., wheel 81-1), and the other electric motor control unit 20 (e.g., electric motor control unit 20-3) detects the occurrence of skidding of the wheel 81 (e.g., wheel 81-3) and reduces the power supplied to the electric motor 31 (e.g., electric motor 31-3), the electric motor control unit 20 may increase the power supplied to the electric motor 31 (e.g., electric motor 31-1).

[0131] In other words, if the detection unit 23 does not detect the occurrence of wheel slide of the wheel 81 and the adjustment unit 24 of another motor control unit 20 reduces the power supplied to the motor 31, the adjustment unit 24 may increase the power supplied to the motor 31. The motor control unit 20 that has adjusted the power to be reduced in response to the occurrence of slide may notify the other motor control unit 20 via CAN communication of information that the power has been reduced. This makes it possible to ensure braking force for the entire vehicle even when slide occurs. The information that the power has been reduced is information equivalent to the notification information that the motor control unit 20 sends to the power receiver 10.

[0132] [Variation 2] The slave motor control unit 20 may determine whether the master receiver 10 is abnormal (whether it has entered an abnormal state). The motor control unit 20 may determine that the receiver 10 is abnormal when it has not received communication data such as a communication request from the receiver 10 for a predetermined period of time (e.g., one second) or more. When it determines that the receiver 10 is abnormal and receives an emergency braking command, a specific motor control unit 20 may function as the master. In other words, the motor control unit 20 may determine that the receiver 10 is abnormal, and when it determines that an abnormality has occurred, the specific motor control unit 20 may take on the role of master in place of the receiver 10 determined to be abnormal when it receives an emergency command (motor control units 20 other than the specific motor control unit 20 functioning as the master remain slaves).

[0133] The electric motor control unit 20 that has become the master may control the adjustment of power (increase or decrease of power determined based on an emergency braking command) in the other electric motor control units 20. Also, although this is also related to Modification 1, the electric motor control unit 20 that has become the master may receive notification information (information that the power has been reduced, information that the power has been increased) from the other electric motor control units 20 and adjust the braking force of the entire vehicle.

[0134] [Variation 3] One electric motor control unit 20 may be provided for one axle 80 (two wheels 81). In other words, although the example shown in FIG. 1 is an example in which one electric motor control unit 20 controls one braking unit 30 (electric motor 31, friction material 32), one electric motor control unit 20 may control two braking units 30. In a configuration in which one electric motor control unit 20 controls one braking unit 30, a situation may arise in which the braking forces of the left and right wheels 81 of the same wheel 80 are different (for example, when one electric motor control unit 20 malfunctions), but when one electric motor control unit 20 controls two braking units 30, the situation described above does not occur.

[0135] [Variation 4] Although the CAN communication is described as being used between the receiver 10 and the motor control unit 20, other communication standards (for example, Ethernet) may also be used.

[0136] [Variation 5] Although the electric motor control unit 20 and the braking unit 30 have been described as being separate entities, the electric motor control unit 20 and the braking unit 30 may be configured as an integrated unit. In other words, the electric motor control unit 20 (board) may be provided in the braking unit 30, which is also called a base brake.

[0137] The above has described in detail the embodiments of the present invention, including examples and modified examples, but the specific configuration is not limited to this embodiment, and also includes designs within the scope of the present invention that do not deviate from the gist of the present invention.

[0138] For example, among the embodiments disclosed in this specification, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions integrated, and conversely, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions integrated. Regardless of whether the functions are integrated or distributed, it is sufficient that the configuration can achieve the object of the invention.

[0139] A program for realizing the functions of the devices according to the above-described embodiments (e.g., the receiver 10, the motor control device 20) may be stored in a computer-readable storage medium, and the program stored in the storage medium may be read into a computer system and executed to perform processing. Note that the term "computer system" here may also include hardware such as an operating system (OS) or peripheral devices. Furthermore, the term "computer-readable storage medium" refers to a flexible disk, a magneto-optical disk, a writable non-volatile memory such as a ROM (Read Only Memory), a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into a computer system.

[0140] Furthermore, the term "computer-readable storage medium" also includes a medium that stores a program for a certain period of time, such as a volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within an information processing device or a client computer system when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may also be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may also be a so-called differential file (differential program) that can realize the aforementioned functions in combination with a program already stored in the computer system. [Explanation of symbols]

[0141] 1... electromechanical brake control system, 10... receiver, 11... calculation unit, 12... command information transmission unit, 13... notification information reception unit, 14... memory unit, 20 (20-1 to 20-8)... motor control unit (motor control device), 21... command information reception unit, 22... power control unit, 23... detection unit, 24... adjustment unit, 25... notification information transmission unit, 26... emergency command reception unit, 30 (30-1 to 30-8)... braking unit, 31 (31-1 to 31-8)... electric motor, 32 (32-1 to 32-8)... friction material, 80 (80a to 80d)... axle, 81 (81-1 to 81-8)... wheel, 90... rail

Claims

1. An electromechanical brake control system including: a receiver; and a plurality of electric motor control units that control, in accordance with command information transmitted from the receiver, electric motors of a plurality of braking units for braking a plurality of wheels of a vehicle, respectively; The receiver is a calculation unit that calculates a target braking force of the braking unit that transmits power of the electric motor to drive a friction material to brake the wheel based on a braking command; a command information transmitting unit that transmits the command information including the calculated target braking force to a plurality of electric motor control units; and The electric motor control unit a command information receiving unit that receives the transmitted command information; a power control unit that controls the power supplied to the electric motor based on the command information; a detection unit that detects at least one of the occurrence of wheel skid, the occurrence of wheel mirroring, and a change in the coefficient of friction between the wheel and the contact surface of the friction material or the rail, based on at least one measurement result of the wheel speed, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; an adjustment unit that adjusts the power supplied to the electric motor based on the command information in accordance with the detection result of the detection unit; An electromechanical brake control system having:

2. the detection unit detects the occurrence of wheel slippage based on the measurement result of the wheel speed, The adjustment unit reduces the power supplied to the electric motor based on the command information when the detection unit detects occurrence of wheel slippage.

10. The electromechanical brake control system of claim 1.

3. the detection unit detects occurrence of mirror finishing of the wheel based on the pressing force, The adjustment unit increases the power supplied to the electric motor based on the command information when the detection unit detects the occurrence of mirroring of the wheel.

10. The electromechanical brake control system of claim 1.

4. the detection unit detects a change in the coefficient of friction between the wheel and the friction material or the contact surface between the wheel and the rail based on the measurement results of the temperature of the friction material and the wheel speed; The adjustment unit reduces the power supplied to the electric motor based on the command information when the detection unit detects an increase in the friction coefficient, and increases the power supplied to the electric motor based on the command information when the detection unit detects a decrease in the friction coefficient.

10. The electromechanical brake control system of claim 1.

5. The electric motor control unit a notification information transmitting unit that, when the adjusting unit is adjusting the power supplied to the electric motor based on the command information, transmits to the receiver notification information including a notification that the adjusting unit is adjusting the power supplied to the electric motor based on the command information; and The receiver is a notification information receiving unit for receiving the transmitted notification information; have 10. The electromechanical brake control system of claim 1.

6. The adjustment unit increases the electric power supplied to the electric motor when the detection unit does not detect the occurrence of wheel slippage and the adjustment unit of another electric motor control unit reduces the electric power supplied to the electric motor.

3. The electromechanical brake control system of claim 2.

7. The electric motor control unit has an emergency command receiving unit that receives an emergency command, the power control unit controls the power supplied to the electric motor based on the emergency command, giving priority to the emergency command over the command information; The adjustment unit adjusts the power supplied to the electric motor based on the emergency command in accordance with the detection result of the detection unit.

5. An electromechanical brake control system according to claim 2 or claim 4.

8. An electric motor control device that controls an electric motor of a braking unit for braking wheels of a vehicle, a command information receiving unit that receives command information including a target braking force of the braking unit calculated based on a braking command; a power control unit that controls the power supplied to the electric motor based on the command information; a detection unit that detects at least one of the occurrence of wheel skidding, the occurrence of wheel mirroring, and a change in the coefficient of friction between the wheel and the friction material of the braking unit or the contact surface of the rail, based on at least one measurement result of the wheel speed, the pressing force pressing the friction material of the braking unit against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; an adjusting unit that adjusts the power supplied to the electric motor based on the command information in accordance with the detection result of the detecting unit; An electric motor control device comprising:

9. In an electromechanical brake control system including a charge receiver and a plurality of electric motor control devices that control electric motors of a plurality of braking units for braking a plurality of wheels of a vehicle in accordance with command information transmitted from the charge receiver, a program that causes a first computer to function as the charge receiver and a second computer to function as the electric motor control device, The first computer a calculation means for calculating a target braking force of the braking unit that transmits power of the electric motor to drive a friction material to brake the wheel based on a braking command; a command information transmitting means for transmitting the command information including the calculated target braking force; It functions as The second computer a command information receiving means for receiving the transmitted command information; power control means for controlling the power supplied to the electric motor based on the command information; a detection means for detecting at least one of occurrence of wheel skidding, occurrence of wheel mirroring, and change in the coefficient of friction between the wheel and the contact surface of the friction material or the rail, based on at least one measurement result of the wheel speed, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is running, and the condition of the wheel; an adjusting means for adjusting the power supplied to the electric motor based on the command information in accordance with the detection result by the detecting means; A program that functions as a

10. A program for causing an electric motor control device that controls an electric motor of a braking unit for braking wheels of a vehicle to function as a computer, The computer a command information receiving means for receiving command information including a target braking force of the braking unit calculated based on a braking command; power control means for controlling the power supplied to the electric motor based on the command information; a detection means for detecting at least one of occurrence of wheel skidding, occurrence of wheel mirroring, and change in the coefficient of friction between the wheel and the friction material of the braking unit or the contact surface of the rail, based on at least one measurement result of the wheel speed, the pressing force pressing the friction material of the braking unit against the contact surface of the wheel, the condition of the rail on which the vehicle is running, and the condition of the wheel; an adjusting means for adjusting the power supplied to the electric motor based on the command information in accordance with the detection result by the detecting means; A program that functions as a

11. A brake control method using a power receiver and a plurality of electric motor control devices that control electric motors of a plurality of braking units for braking a plurality of wheels of a vehicle in accordance with command information transmitted from the power receiver, the method comprising: a calculation step of calculating, based on a braking command, a target braking force of the braking unit that transmits power of the electric motor to drive a friction material and brakes the wheel, using the receiver; a transmitting step of transmitting the command information including the target braking force calculated in the calculating step to a plurality of motor control devices using the receiver; a command information receiving step of receiving the command information transmitted in the transmitting step by using the electric motor control device; a power control step of controlling power supplied to the electric motor based on the command information using the electric motor control device; a detection step of detecting, using the motor control device, at least one of occurrence of wheel skid, occurrence of wheel mirroring, and change in the coefficient of friction between the wheel and the friction material or the contact surface of the rail, based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material against the contact surface of the wheel, the condition of the rail on which the vehicle is traveling, and the condition of the wheel; an adjusting step of adjusting the power supplied to the electric motor based on the command information using the electric motor control device in accordance with the detection result in the detecting step; A brake control method comprising:

12. A brake control method using an electric motor control device that controls an electric motor of a braking unit for braking wheels of a vehicle, a command information receiving step of receiving command information including a target braking force of the braking unit calculated based on a braking command; a power control step of controlling power supplied to the electric motor based on the command information; a detection step of detecting at least one of occurrence of wheel skid, occurrence of wheel mirroring, and change in the coefficient of friction between the wheel and the friction material of the braking unit or the contact surface of the rail, based on at least one measurement result of the wheel speed of the wheel, the pressing force pressing the friction material of the braking unit against the contact surface of the wheel, the condition of the rail on which the vehicle is running, and the condition of the wheel; an adjusting step of adjusting the power supplied to the electric motor based on the command information in accordance with the detection result in the detecting step; A brake control method comprising:

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