Control device and control method of electric power steering device

Abstract

A control device and a control method for an electric power steering device are provided. The design man-hours associated with the control of an electric power steering device can be reduced. A control device controls an electric power steering device, the electric power steering device having a motor that generates a steering torque and applies a steering force to a steering mechanism of a vehicle, wherein the control device has a control unit that receives a specific signal and controls the motor based on a request value represented by the received signal, wherein the specific signal is a signal representing a request value associated with the action of the motor and includes a specific type of request value and an attribute of the request value.

Description

Technical Field

[0001] The invention relates to a control device and a control method of an electric power steering device. Background Art

[0002] The electric power steering device of a vehicle requires high reliability and various steering performances. Therefore, in the development of the electric power steering device, the increase in design man-hours has become a problem, and the design is expected to be more efficient. For example, Patent Document 1 discloses a device that assists in the design of a control device that controls an electric power steering device. The design assistance device of Patent Document 1 divides the program of the control device into a plurality of control modules that are distinguished by control functions, and has a table that corresponds the classification of control modules, design parameters, and required specifications. As a result, when the design of the electric power steering device advances from the upstream process to the downstream process, the required specifications can be efficiently reflected.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2008-269080

[0004] However, when a new function of a vehicle is proposed, the specification of the electric power steering device may be greatly changed. In this case, it is difficult to achieve efficient design, so it is desired to reduce the design man-hours. Summary of the invention

[0005] The present invention has been made in view of the above background, and an object of the present invention is to reduce the number of design steps related to control of an electric power steering device.

[0006] As a first method for achieving the above-mentioned purpose, there is provided a control device that controls an electric power steering device, which has a motor that generates steering torque and applies steering force to a steering mechanism of a vehicle, wherein the control device has a control unit that receives a specific signal and controls the motor based on a request value represented by the received specific signal, wherein the specific signal is a signal representing a request value related to the action of the motor, and includes a specific type of request value and attributes of the request value.

[0007] In the above-mentioned electric power steering device, it can also be configured that the control device has an arbitration unit, which receives a request signal sent by an external device of the control device, and the arbitration unit generates the specific signal by arbitrating the request signal sent by the external device, and sends the generated specific signal to the control unit.

[0008] The electric power steering device may be configured to receive the request signal transmitted by an apparatus external to the control device through arbitration.

[0009] In the above-mentioned electric power steering device, the control device may include priority designation information for determining a priority of the specific signal, and the control unit may control the motor based on a request value indicated by the specific signal in accordance with the priority determined by the priority designation information.

[0010] In the above-mentioned electric power steering device, it can also be configured that the priority designation information is information that corresponds the attribute of the request value represented by the specific signal with the priority of processing the request value represented by the specific signal, and the control unit controls the motor based on the request value represented by the specific signal according to the priority determined by the priority designation information.

[0011] In the electric power steering device described above, the attribute of the request value indicated by the specific signal may include at least one of a type of the request value indicated by the specific signal and a functional safety level of the request value indicated by the specific signal.

[0012] In the above-mentioned electric power steering device, it can also be configured that the attribute of the request value represented by the specific signal includes the functional safety level of the request value represented by the specific signal, and the priority designation information is the following information: for the specific signals with different functional safety levels, it is decided to give priority to the processing based on the specific signal with a higher functional safety level; for the specific signals with the same functional safety level, it is decided to give priority to the processing based on the specific signal with a larger request value.

[0013] In the electric power steering device, the steering mechanism may include a steering wheel, and the request value included in the specific signal may be a value indicating an additional torque added to the steering wheel operation amount when the motor is operated according to the steering wheel operation amount.

[0014] As a second method for achieving the above-mentioned purpose, there is provided a control method for an electric power steering device, which includes a motor that generates steering torque and applies steering force to a steering mechanism of a vehicle, wherein a specific signal is input into a control device that controls the motor, and the specific signal is a signal representing a request value related to the action of the motor, including a specific type of request value and an attribute of the request value, and the motor is controlled by the control device based on the request value represented by the specific signal.

[0015] Effects of the Invention

[0016] According to the above configuration, even when a design change related to the operation of the electric power steering device occurs, it is possible to cope with the change without significantly changing the specifications of the control device, thereby reducing the number of design steps related to the control of the electric power steering device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the electric power steering device.

[0018] Figure 2 It is a diagram showing the structure of a control device.

[0019] Figure 3 It is an explanatory diagram showing an example of processing by the control device.

[0020] Figure 4 is a schematic diagram showing an example of priority mapping.

[0021] Figure 5 This is a flowchart showing the operation of the control device.

[0022] Figure 6 This is a flowchart showing the operation of the control device.

[0023] Description of symbols

[0024] 10…Electric power steering device, 12…Steering wheel, 20…Front wheel, 22…Motor, 22a…Output shaft, 28…Torque sensor, 32…Steering angle sensor, 100…Control device, 102…Arbitration unit, 104…Control unit, 112, 114…Priority mapping (priority designation information), 200…Upper control unit, 201…First upper control unit, 202…Second upper control unit, 203…Third upper control unit, 211…Driving assistance device, 212…Parking assistance device, 213…Occupant monitoring device, S1, S2, S3…Signal (request signal), S11…Specific signal. DETAILED DESCRIPTION

[0025] [1. Structure of the electric power steering device]

[0026] Figure 1 FIG. 1 is a schematic diagram of the structure of the electric power steering device 10 according to the embodiment. Figure 1 Devices related to the control of the electric power steering device 10 are also shown in the figure.

[0027] The electric power steering device 10 is a device that is mounted on a vehicle and performs steering of the vehicle. For example, the electric power steering device 10 is mounted on a four-wheel vehicle. The electric power steering device 10 includes a steering wheel 12 (steering wheel) that is operated by a driver of the vehicle.

[0028] The vehicle equipped with the electric power steering device 10 generates a steering torque by a motor 22 described later according to the operation of the steering wheel 12 to assist the driver's steering. In addition, the above-mentioned vehicle has the function of performing steering exceeding the operation amount of the steering wheel 12 and operations not corresponding to the operation of the steering wheel 12 through the electric power steering device 10.

[0029] The electric power steering device 10 includes a steering wheel 12, a steering shaft 14, a rack shaft 16, a tie rod 18, and left and right front wheels 20 as steered wheels. The steering shaft 14, the rack shaft 16, and the tie rod 18 constitute a manual steering system.

[0030] The manual steering system directly transmits the steering action of the driver on the steering wheel 12 to the front wheels 20. The steering shaft 14 includes: a main steering shaft 52, which is integrally connected to the steering wheel 12; a pinion shaft 54, which is provided with a pinion 56 of a rack and pinion mechanism; and a universal joint 58, which connects the main steering shaft 52 and the pinion shaft 54. The pinion 56 meshes with the rack teeth 62 of the rack shaft 16 that can reciprocate in the vehicle width direction.

[0031] The rotational force generated by the driver operating the steering wheel 12, that is, the steering torque Tr is transmitted to the pinion shaft 54 ​​via the main steering shaft 52 and the universal joint 58. The steering torque Tr is converted into thrust by the pinion 56 of the pinion shaft 54 ​​and the rack teeth 62 of the rack shaft 16, and the thrust displaces the rack shaft 16 in the vehicle width direction. With the displacement of the rack shaft 16, the steering tie rod 18 steers the front wheels 20, thereby changing the direction of the vehicle.

[0032] The electric power steering device 10 includes a motor 22 , a worm wheel 24 , a worm gear mechanism 26 , a torque sensor 28 , a steering angle sensor 32 , and a control device 100 .

[0033] The motor 22, the worm wheel 24, and the worm gear mechanism 26 constitute an auxiliary drive system. The auxiliary drive system generates a steering assist force to assist the driver in steering and to replace the driver in steering. The output shaft 22a of the motor 22 is connected to the worm wheel 24, and further connected to the rack shaft 16 via the worm gear mechanism 26. The worm gear mechanism 26 meshing with the worm wheel 24 is formed on the pinion shaft 54, and the pinion shaft 54 ​​is connected to the rack shaft 16.

[0034] The torque sensor 28, the steering angle sensor 32 and the control device 100 constitute an auxiliary control system. The auxiliary control system controls the auxiliary drive system. The motor 22 is, for example, a three-phase AC brushless motor. Under the control of the control device 100, power is supplied to the motor 22 from an inverter not shown, and the motor 22 generates a driving force corresponding to the supplied power. The driving force of the motor 22 is transmitted to the rack shaft 16 via the output shaft 22a, the worm gear 24 and the pinion shaft 54 ​​to steer the vehicle.

[0035] The torque sensor 28 detects the steering torque Tr of the electric power steering device 10 and outputs the detected value to the control device 100. The torque sensor 28 is, for example, Figure 1 The steering angle sensor 32 is provided on the pinion shaft 54 ​​and detects the steering torque Tr based on the change in magnetic characteristics caused by magnetostriction. The steering angle sensor 32 detects the steering angle θs of the electric power steering device 10 and outputs the steering angle θs to the control device 100 .

[0036] The control device 100 performs steering assist control based on the steering angle θs detected by the steering angle sensor 32 and the value of the steering torque Tr detected by the torque sensor 28. In the steering assist control, the control device 100 operates the motor 22 according to the operation amount of the steering wheel 12 to generate an assist torque. Through the steering assist control, the driver can operate the steering wheel 12 with a lighter force. In the steering assist control, the control device 100 steers the front wheels 20 according to the operation amount of the steering wheel 12.

[0037] Furthermore, the control device 100 is connected to a higher-level control unit 200. The number of higher-level control units 200 connected to the control device 100 is not limited, and it is also possible to configure a configuration in which a plurality of higher-level control units 200 are connected to the control device 100. Figure 1 , a configuration in which a first host control unit 201 , a second host control unit 202 , and a third host control unit 203 are connected to the control device 100 as the host control unit 200 is illustrated.

[0038] The upper control unit 200 is a device for controlling the vehicle posture, and is composed of a single ECU (Electronic Control Unit) or a plurality of devices including an ECU. The upper control unit 200 requests the control device 100 to steer the front wheels 20 not corresponding to the amount of operation of the steering wheel 12. The ECU has a processor composed of a microcontroller or a CPU (Central Processing Unit). The ECU may also include a memory for storing data and programs for processing by the processor, a transceiver circuit for transmitting and receiving signals, etc.

[0039] The upper control unit 200 and the control device 100 are connected, for example, via a CAN (Controller Area Network) bus. In this structure, the upper control unit 200 can send a signal to the control device 100 via the CAN bus, and is not limited to a structure in which the control device 100 and the upper control unit 200 are directly connected in a one-to-one manner.

[0040] The host control unit 200 is, for example, a device constituting an advanced driver-assistance system (ADAS: Advanced Driver-Assistance Systems).

[0041] As the function of the upper control unit 200, for example, a steering assist function that adds a steering angle to the steering of the steering wheel 12 by the driver can be cited. More specifically, it is a system having a lane departure prevention (RDM: Road Departure Mitigation) function that steers in a manner that does not deviate from the lane of the road while the vehicle is traveling, a straight driving assist (SDA: Straight Driving Assist) function that assists the straight driving of the vehicle, and a motion adaptive (Motion Adaptive) function that stabilizes the posture of the vehicle while traveling. The upper control unit 200 can also be a system that performs steering without the operation of the steering wheel 12. Specifically, an automatic lane change (ALC: Automatic Lane Change) function that automatically performs the action of changing lanes, a lane keeping assist (LKA: Lane Keep Assistance) function that maintains the state of the vehicle traveling near the center of the lane, and an automatic driving (AD: Automated Drive) function that automatically accelerates, decelerates, and steers the vehicle. The AD function is, for example, a function that controls the vehicle in a so-called non-manual state in which the driver takes his hands off the steering wheel 12. In addition, the AD function may also be a function of controlling the vehicle under the condition of a so-called manual state in which the driver touches the steering wheel 12 with his hand. In addition, as a function of the upper control unit 200, an automatic parking system (APS: Automatic Parking System) that moves the vehicle to a specified parking position may be cited. In addition, as a function of the upper control unit 200, an emergency steering (AES: Automatic Emergency Steering) function that steers to avoid a collision and a side collision mitigation (SCM: Side Collision Mitigation) function may be cited. In addition, as a function of the upper control unit 200, an MES (Medical Emergency Stop) function that detects the driver's physical condition and stops the vehicle in an emergency and a driver monitoring (DAM: Driver Attention Monitor) function that monitors the driver's condition and steers to warn the driver may be cited.

[0042] The host control unit 200 is configured as a device having, for example, one or more of the functions listed above. Figure 1The first upper control unit 201, the second upper control unit 202, and the third upper control unit 203 shown are ECUs having one or more functions described above, and transmit signals S1, S2, and S3 associated with the functions. The signals S1, S2, and S3 are signals requesting steering by the electric power steering device 10. The control device 100 controls the motor 22 based on the signals S1, S2, and S3 to perform steering. The signals S1, S2, and S3 correspond to an example of a request signal.

[0043] [2. Structure of control device]

[0044] Figure 2 It is a diagram showing the structure of the control device 100.

[0045] The control device 100 includes an arbitration unit 102 and a control unit 104. The arbitration unit 102 and the control unit 104 may be respectively constituted by independent ECUs, or the control device 100 may be constituted by an ECU in which the arbitration unit 102 and the control unit 104 are integrated.

[0046] Signals S1, S2, and S3 are input to the arbitration unit 102. The arbitration unit 102 has a priority map 112. The priority map 112 includes information on the priority of determining the execution order of the signals S1, S2, and S3. The priority map 112 corresponds to an example of priority designation information. The arbitration unit 102 performs arbitration of the signals S1, S2, and S3 according to the priority map 112, and sends the arbitrated specific signal S11 to the control unit 104.

[0047] The control unit 104 performs processing indicated by the specific signal S11 based on the steering torque Tr input from the torque sensor 28 and the steering angle θs input from the steering angle sensor 32, and controls the motor 22. The control unit 104 may not be directly connected to the motor 22. For example, the control unit 104 may control an inverter (not shown) that supplies power to the motor 22.

[0048] The control unit 104 has a priority map 114. The priority map 114 includes information of a priority for determining the execution order of the specific signal S11. The priority map 114 may be the same information as the priority map 112, or may be different information. When the request indicated by the specific signal S11 conflicts, the control unit 104 executes the processing corresponding to the request according to the priority determined by the priority map 114.

[0049] [3. Operation of the control device]

[0050] The operation of the control device 100 will be described in detail with reference to specific examples.

[0051] Figure 3It is an explanatory diagram showing an example of processing by the control device 100 .

[0052] exist Figure 3 In the figure, a driving assistance device 211 is shown as a specific example of the first upper control unit 201 , a parking assistance device 212 is shown as a specific example of the second upper control unit 202 , and an occupant monitoring device 213 is shown as a specific example of the third upper control unit 203 .

[0053] The signals S1, S2, and S3 transmitted by the driving assistance device 211, the parking assistance device 212, and the occupant monitoring device 213 include request values ​​and attributes of the request values. The attributes of the request values ​​include, for example, the type of the request value and the function associated with the request.

[0054] The driving assistance device 211 has an AD function, an AES function, an MES function, and an SDA function in a non-manual state. In this structure, the types of request values ​​included in the signal S1 are a target steering angle, a vibration request, a vibration direction, and an additional torque. The request value represents the amount of movement of the electric power steering device 10 requested by the driving assistance device 211 to the control device 100. The target steering angle is the angle at which the motor 22 performs steering manipulation, and is the steering angle detected by the steering angle sensor 32. For example, the request value "target steering angle (AD)" is the value of the steering angle specified by the AD function, and is a signal requesting the control unit 104 to drive the motor 22 using this value as a target.

[0055] Similarly, the "target steering angle (AES)" included in the signal S1 is a request value requested by the AES function, the "target steering angle (MES)" is a request value requested by the MES function, and the "additional torque (SDA)" is a request value requested by the SDA function.

[0056] The attribute of the request value of signal S1 includes information indicating that the type of the request value is a target steering angle, additional torque, vibration request, or vibration direction. In addition, the attribute of the request value of signal S1 is information indicating that the function related to the request value is an AD function, an AES function, an MES function, or an SDA function.

[0057] Vibration is a function of vibrating the steering wheel 12 by intermittently switching the rotation direction of the output shaft 22a by the motor 22. For example, when the driver is determined by the driver monitoring function that the driver is not concentrating on driving, the driving assistance device 211 sends a signal S1 requesting vibration. The vibration request is a control signal requesting the control unit 104 to execute the vibration function. The vibration direction is a request value that specifies the direction in which the output shaft 22a is moved when the vibration function starts, and any one of CW (clockwise) and CCW (counterclockwise) is specified as the rotation direction of the steering wheel 12 observed by the driver. The control unit 104 can also generate vibrations in multiple modes through the motor 22. In this case, the signals S1, S2, and S3 may also include request values ​​that specify the vibration mode.

[0058] The driving assistance device 211 transmits the signal S1 at the timing when the AD function, the AES function, and the MES function make requests. Therefore, the timing when the driving assistance device 211 transmits the signal S1 and the type of request included in the signal S1 vary depending on the execution state of the functions of the driving assistance device 211.

[0059] The parking assist device 212 is an automatic parking system (APS). In the process of parking the vehicle at the designated parking position, the parking assist device 212 requests the control device 100 to perform steering and specifies a target steering angle. The signal S2 includes "target steering angle (APS)" as a request value of the APS. The function of the automatic parking system of this embodiment is executed on the condition that the driver does not touch the steering wheel 12. The attribute of the request value is information indicating that the type of the request value is the target steering angle, and information indicating that the function associated with the request value is the APS function.

[0060] The occupant monitoring device 213 has a driver monitoring (DAM) function. When the occupant monitoring device 213 needs to notify the driver, it sends a vibration request and a vibration direction as a signal S3. The attribute of the request value is information indicating that the type of the request value is a vibration request or a vibration direction. The signal S3 may also include information indicating that the function associated with the request value is a DAM function as an attribute of the request value, but this is omitted here.

[0061] The arbitration unit 102 performs arbitration processing on the signals S1, S2, and S3. The arbitration processing is a process for resolving conflicts when conflicting requests are made from the upper control unit 200 to the control device 100. Specifically, the so-called conflict includes: (1) a request to perform the same type of control as the control being performed while the control device 100 is performing control of the motor 22 according to any one of the signals S1, S2, and S3; (2) a request to perform the same type of control as the control to be performed before the control device 100 starts controlling the motor 22 according to any one of the signals S1, S2, and S3. There is a possibility that the same signal will conflict. For example, the first signal S1 sent by the driving assistance device 211 and the second signal S1 may conflict.

[0062] The arbitration unit 102 converts the signals S1, S2, and S3 into a standardized specific signal S11 that the control unit 104 can receive. In the present embodiment, the specific signal S11 includes a request value, a type of request value, and a functional safety level of the request value. The type of the request value and the functional safety level of the request value are examples of attributes of the request value. The functional safety level can also be referred to as a safety requirement level. As a specific example of the functional safety level, the SIL (Safety Integrity Level) defined by IEC61508 and the ASIL (Automotive Safety Integrity Level) defined by ISO26262 can be cited. In the present embodiment, an example of using ASIL is described. The specific signal S11 of the present embodiment includes a request value, a type of request value, and the ASIL level of the request value, namely ASIL-A, ASIL-B, ASIL-C, and ASIL-D. The specific signal S11 is a signal that includes the type of request value and the attributes of the request value in a specific manner.

[0063] When the signals S1, S2, and S3 conflict, the arbitration unit 102 determines the priority based on the attributes of the request values ​​represented by the conflicting signals. The attributes of the request value used for determining the priority may include the robustness of the request value. Robustness can be said to be the reliability of the request value, for example, the functional safety level can be cited. In this embodiment, the ASIL level is used as the attribute of robustness. The arbitration unit 102 assigns an ASIL level corresponding to the information representing the function associated with the request value in the attributes of the request value contained in the signals S1, S2, and S3. For example, ASIL-D corresponds to functions that are executed non-manually such as AD or APS, AES functions, and MES functions, and ASIL-B corresponds to manual functions, and vibration requests and vibration directions are set to be outside the objects of ASIL.

[0064] Figure 4112 is a schematic diagram showing an example of the priority map 112 .

[0065] The priority map 112 determines the priority of the request value based on the type of the request value and the ASIL level of the request value. Figure 4 The priority map 112 shown is a method of specifying a priority request value when comparing two request values, but it can also be information that determines the order of priority for more than three request values, for example. The priority map 112 determines to give priority to request values ​​with higher ASIL levels for the same type of request values. In addition, the priority map 112 determines the priority to be low in the order of target steering angle, additional torque, and vibration in association with the type of request value. For example, regardless of the ASIL level, the target steering angle takes precedence over the additional torque. For the same type of request value, the request value of ASIL-D takes precedence over the request value of ASIL-B. Vibration can be executed in parallel with the action of the control unit 104 based on the request value of the target steering angle and the action of the control unit 104 based on the request value of the additional torque.

[0066] The priorities of the priority map 112 are not limited to those described above. For example, the basic priorities may be set as described above, and exceptions may be provided. Specifically, in the priority map 112, a setting may be adopted in which the priority of the request value for the additional torque of ASIL-D is higher than the target steering angle of ASIL-B. Thus, in the present embodiment, the priority of the request value is determined by the priority map 112, and therefore a priority that does not conform to the basic priority rules may also be set. The same is true for the priority map 114.

[0067] In addition, as a rule for determining the priority, it is of course possible to set a rule that gives priority to the ASIL level over the type of request value.

[0068] Here, as the robustness of the request value, the robustness of the communication path for inputting the request value to the control device 100 may be used. For example, when the upper control unit 200 and the control device 100 are connected via a CAN bus, the priority of the request value sent to the control device 100 via the communication path using a message authentication code (MAC) may be higher than the request value sent without using a MAC.

[0069] In the present embodiment, the priority map 114 included in the control unit 104 is the same information as the priority map 112 .

[0070] Figure 5 1 is a flowchart showing the operation of the control device 100 , and in particular, the operation of the arbitration unit 102 .

[0071] The arbitration unit 102 receives a signal from the upper control unit 200 (step ST1), and determines whether the received signal conflicts with other signals (step ST2). In step ST2, for example, it is determined whether the request value of the signal received in step ST1 conflicts with the request value of the signal received before step ST1. In addition, when the arbitration unit 102 receives multiple signals with a short time difference in step ST1, it determines whether the request values ​​of these multiple signals conflict.

[0072] If it is determined that there is a conflict (step ST2; yes), the arbitration unit 102 starts arbitration processing (step ST3). In the arbitration processing, the arbitration unit 102 determines the functional safety level of the request value represented by the conflicting signal (step ST4). The arbitration unit 102 determines the priority according to the priority map 112 based on the type and functional safety level of the conflicting request value (step ST5). The arbitration unit 102 selects the request value with a higher priority (step ST6).

[0073] The arbitration unit 102 generates a specific signal S11 including the selected request value, the type of the selected request value, and the functional safety level determined in step ST4 (step ST7 ), and transmits the specific signal S11 to the control unit 104 (step ST8 ).

[0074] When the arbitration unit 102 determines in step ST1 that the signals received do not conflict (step ST2 ; No), the process proceeds to step ST7 and executes the process.

[0075] The control unit 104 controls the motor 22 based on the specific signal S11 transmitted from the arbitration unit 102. The control unit 104 has a function of performing arbitration based on the priority map 114 when a conflict of the specific signals S11 occurs.

[0076] Figure 6 It is a flowchart showing the operation of the control device 100 , and particularly shows the operation of the control unit 104 .

[0077] The control unit 104 receives the specific signal S11 (step ST11), and determines whether the request value of the received specific signal S11 conflicts with the control being executed (step ST12). If it is determined that there is no conflict (step ST12; No), the control unit 104 controls the motor 22 according to the specific signal S11 received in step ST11 (step ST13).

[0078] If it is determined that there is a conflict (step ST12; Yes), the control unit 104 determines the priority of the request value based on the priority map 114 (step ST14). The control unit 104 selects the request value with a higher priority (step ST15). The control unit 104 performs control according to the selected request value (step ST13).

[0079] In this way, the specific signal S11 generated by the arbitration unit 102 through arbitration is input to the control unit 104. The request value included in the specific signal S11 is pre-specified. The arbitration unit 102 generates the specific signal S11 based on the signals S1, S2, and S3, and the specific signal S11 includes the request value and the attribute of the request value that conform to the regulations of the control unit 104. Therefore, the control unit 104 only needs to correspond to the request value included in the specific signal S11.

[0080] exist Figure 3 In the example, as the request values ​​that the specific signal S11 may contain, there are steering angle control mode, target steering angle, additional torque, torque upper limit value, vibration mode and vibration direction. In this example, the steering angle control mode, target steering angle, additional torque and torque upper limit value are request values ​​of ASIL-D or ASIL-B. That is, the control unit 104 only needs to have the function of controlling the motor 22 based on the request values ​​of the steering angle control mode, target steering angle, additional torque, torque upper limit value, vibration mode and vibration direction. In addition, the control unit 104 only needs to be able to distinguish the request values ​​of the five stages of ASIL-D, ASIL-C, ASIL-B, ASIL-A and QM as the attributes of the request values.

[0081] For example, if the upper control unit 200 is a device having a new function different from the functions listed above, the arbitration unit 102 only needs to be equipped with a function of generating the specific signal S11 based on the request value output by the new device. In this case, the new function can be installed in the vehicle without changing the design of the control unit 104.

[0082] The feature is that the specific signal S11 can include additional torque. The additional torque is, for example, the request value of the SDA function, the lane departure prevention (RDM) function, and the motion adaptive function. The request value of these functions can be set to the steering angle of the electric power steering device 10, but the request value of the steering angle may become a request value with a high functional safety level. In contrast, the additional torque indicating the addition of the steering angle can reduce the functional safety level under the premise of a manual state, especially under the premise of limiting the value of the additional torque to be less than a constant value. Therefore, the control corresponding to the request value of the additional torque can be performed by the control unit 104, so that the opportunity of the control device 100 to perform a control with a high functional safety level can be reduced. This structure can be realized by, for example, the upper control unit 200 converting the request value of the straight driving assist (SDA) function, the lane departure prevention (RDM) function, and the motion adaptive function from the request value of the steering angle to the request value of the additional torque. In addition, the arbitration unit 102 can also be configured to convert the request value of the steering angle to the request value of the additional torque when generating the specific signal S11.

[0083] [4. Other embodiments]

[0084] The above-described embodiment is a specific example to which the present invention is applied, and does not limit the form to which the invention is applied.

[0085] In the above embodiment, the configuration in which the arbitration unit 102 performs arbitration of the signals S1, S2, and S3 is described, but the upper control unit 200 may generate the signals S1, S2, and S3 after performing arbitration and transmit them to the control device 100. For example, when the upper control unit 200 transmits a request value with a high functional safety level (e.g., a request value of ASIL to D) to the control device 100, the upper control unit 200 may perform arbitration in the upper control unit 200 and then transmit the arbitrated signals S1, S2, and S3 to the control device 100. In this case, the first upper control unit 201, the second upper control unit 202, and the third upper control unit 203 may communicate with each other via the CAN bus, and the control device 100 may receive the signals S1, S2, and S3 in the order and timing after arbitration. The upper control unit 200 that performs processing with a high functional safety level has reliability corresponding to the high functional safety level. By using such a higher-level control unit 200 to perform arbitration, the reliability requirements on the arbitration unit 102 can be reduced, and the control device 100 can be realized more easily.

[0086] In the above embodiment, the structure of controlling the electric power steering device 10 for steering the front wheels 20 of the vehicle is described, but this is an example. The power steering device controlled by the present invention can be any device that maintains and changes the posture of the vehicle by steering the wheels. For example, it can be a device that steers four wheels including the front wheels 20 and the rear wheels of the vehicle, or it can be a device that steers only the rear wheels.

[0087] The control device 100 may be configured to include one or more control devices in addition to the arbitration unit 102 and the control unit 104. In addition, the control device 100 may be configured to control the electric power steering device 10 based on the detection values ​​of other sensors in addition to the torque sensor 28 and the steering angle sensor 32. In addition, the control device 100 is not limited to a configuration including hardware corresponding to the arbitration unit 102 and the control unit 104, and may be a configuration in which the functions of the arbitration unit 102 and the control unit 104 are realized by executing a program by a processor.

[0088] [5. Structure supported by the above-mentioned embodiment]

[0089] The above-mentioned embodiment is a specific example of the following structure.

[0090] (Item 1) A control device that controls an electric power steering device, the electric power steering device having a motor that generates steering torque to apply steering force to a steering mechanism of a vehicle, wherein the control device has a control unit that receives a specific signal and controls the motor based on a request value represented by the received specific signal, wherein the specific signal is a signal representing a request value related to the operation of the motor, and includes a specific type of request value and attributes of the request value.

[0091] According to the control device of the first item, the control unit only needs to be able to process a specific type of request value. Therefore, when making the control device compatible with a new function accompanying the steering of the vehicle, it is not necessary to significantly change the design of the control unit that controls the motor. Therefore, it is possible to reduce the design man-hours related to the control of the electric power steering device.

[0092] (Item 2) A control device according to Item 1, wherein the control device has an arbitration unit that receives a request signal sent by a device outside the control device, and the arbitration unit generates the specific signal by arbitrating the request signal sent by the external device, and sends the generated specific signal to the control unit.

[0093] According to the control device of the second item, in addition to the control unit for controlling the motor, an arbitration unit for arbitrating the request signal sent to the control device is also provided, so the control unit only needs to process the specific signal after arbitration. Therefore, in the case of adding a new function accompanying the steering of the vehicle, the design change of the control unit can be suppressed to a small-scale change, and the design man-hours related to the control of the electric power steering device can be reduced.

[0094] (Item 3) The control device according to Item 2, wherein the control device receives the request signal transmitted by an apparatus external to the control device through arbitration.

[0095] According to the control device of the third item, the control device can receive and process the arbitrated request value. For example, when the control device needs to arbitrate a request signal containing a request value with a high functional safety level, a high reliability is required for the control device. In contrast, if the upper control unit that performs processing with a high functional safety level sends the arbitrated request signal, the reliability requirement for the control device can be reduced. Therefore, the design man-hours required for designing the control device can be reduced.

[0096] (Item 4) A control device according to any one of Items 1 to 3, wherein the control device has priority designation information for determining the priority of the specific signal, and the control unit controls the motor based on the request value represented by the specific signal according to the priority determined by the priority designation information.

[0097] According to the control device of the fourth aspect, the motor can be controlled based on the request value indicated by the specific signal without performing complicated arbitration processing.

[0098] (Item 5) A control device according to Item 4, wherein the priority designation information is information that corresponds an attribute of the request value represented by the specific signal to a priority of processing the request value represented by the specific signal, and the control unit controls the motor based on the request value represented by the specific signal according to the priority determined by the priority designation information.

[0099] According to the control device of the fifth item, by utilizing the attribute of the request value, it is possible to easily determine the priority of the request value and execute the control of the motor.

[0100] (Item 6) The control device according to Item 5, wherein the attribute of the request value represented by the specific signal includes at least one of a type of the request value represented by the specific signal and a functional safety level of the request value represented by the specific signal.

[0101] According to the sixth control device, the priority can be determined based on the type of request value and the functional safety level so as to maintain the reliability required for the steering of the vehicle. Thus, a design that satisfies the reliability required for the steering can be realized with less design man-hours.

[0102] (Item 7) A control device according to Item 5 or Item 6, wherein the attribute of the request value represented by the specific signal includes the functional safety level of the request value represented by the specific signal, and the priority designation information is the following information: for the specific signals having different functional safety levels, it is decided to give priority to processing based on the specific signal with a higher functional safety level; and for the specific signals having the same functional safety level, it is decided to give priority to processing based on the specific signal with a larger request value.

[0103] According to the control device of item 7, control based on a request value having a high functional safety level is preferentially executed. Therefore, a design satisfying the reliability required for vehicle steering can be realized with a small number of design man-hours.

[0104] (Item 8) A control device according to any one of Items 1 to 7, wherein the steering mechanism has a steering wheel, and the request value contained in the specific signal is a value representing an additional torque added to the operation amount of the steering wheel when the motor is operated according to the operation amount of the steering wheel.

[0105] According to the control device of claim 8, the motor can be controlled based on the request value of the additional torque, so the processing load in the control unit can be reduced.

[0106] (Item 9) A method for controlling an electric power steering device, the electric power steering device having a motor that generates a steering torque to apply steering force to a steering mechanism of a vehicle, wherein a specific signal is input into a control device that controls the motor, the specific signal being a signal indicating a request value related to an action of the motor, including a specific type of request value and an attribute of the request value, and the motor is controlled by the control device based on the request value indicated by the specific signal.

[0107] According to the control method of the electric power steering device of the ninth item, the control device controls the motor based on a specific type of request value. Therefore, when making the control device correspond to a new function accompanying the steering of the vehicle, it is not necessary to significantly change the design related to the control of the motor. Therefore, it is possible to reduce the design man-hours related to the control of the electric power steering device.

Claims

1. A control device for controlling an electric power steering device, the electric power steering device having a motor for generating a steering torque, and applying a steering force to a steering mechanism of a vehicle, wherein: The control device comprises: an arbitration unit that receives a request signal sent by a device external to the control device and converts the request signal into a standardized specific signal that can be received by the control unit that controls the motor, wherein the request signal is a signal requesting steering by the electric power steering device and includes a target steering angle, a vibration request, a vibration direction, and a request value of an additional torque, the request value indicating an amount of movement of the electric power steering device; and the control unit receives the specific signal and controls the motor based on the request value represented by the received specific signal, wherein the specific signal includes the request value and an attribute of the request value, The specific signal includes the type of the request value and the functional safety level of the request value, The arbitration unit outputs the generated specific signal to the control unit, The control unit has priority designation information for determining the priority of the execution order of the specific signal, The priority designation information is information for determining a priority of processing the request value based on the type of the request value and the functional safety level of the request value. the control unit controls the motor based on the request value indicated by the specific signal according to the priority determined by the priority designation information, The priority of the request value is determined to be lower in the order of the target steering angle, the additional torque, and the vibration. The arbitration unit converts the requested value of the target steering angle into the requested value of the additional torque when generating the specific signal.

2. The control device according to claim 1, wherein: The arbitration unit generates the specific signal by arbitrating a request signal transmitted from the external device.

3. The control device according to claim 2, wherein: The control device receives the request signal transmitted by an apparatus external to the control device through arbitration.

4. The control device according to claim 1, wherein: The priority designation information is information that, for the specific signals with different functional safety levels, determines to prioritize the processing based on the specific signal with a higher functional safety level, and for the specific signals with the same functional safety level, determines to prioritize the processing based on the specific signal with a larger request value.

5. The control device according to any one of claims 1 to 3, wherein: The steering mechanism includes a steering wheel. The request value included in the specific signal is a value indicating an additional torque to be added to the operation amount of the steering wheel when the motor is operated according to the operation amount of the steering wheel.

6. A control method for an electric power steering device, which is used to control the electric power steering device by a control device, the electric power steering device having a motor that generates a steering torque and imparts a steering force to a steering mechanism of a vehicle, wherein: In the control method of the electric power steering device, receiving, by an arbitration unit, a request signal sent by a device external to the control device, the request signal being a signal requesting steering by the electric power steering device, and including a target steering angle, a vibration request, a vibration direction, and a request value for an additional torque, the request value indicating an amount of movement of the electric power steering device, The arbitration unit converts the request signal into a standardized specific signal that can be received by a control unit that controls the motor. The specific signal generated by the arbitration unit is output, The control unit for controlling the motor controls the motor based on the request value when receiving the specific signal output by the arbitration unit and including the request value and the attribute of the request value from the arbitration unit. The specific signal includes the type of the request value and the functional safety level of the request value, The control unit has priority designation information for determining the priority of the execution order of the specific signal, The priority designation information is information for determining a priority of processing the request value based on the type of the request value and the functional safety level of the request value. the control unit controls the motor based on the request value indicated by the specific signal according to the priority determined by the priority designation information, The priority of the request value is determined to be lower in the order of the target steering angle, the additional torque, and the vibration. The arbitration unit converts the requested value of the target steering angle into the requested value of the additional torque when generating the specific signal.

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