Electronic control device

Abstract

In the present invention, an ECU 40 functions as: an acquisition unit 103 that acquires at a speed differential related value relating to a differential value of a parameter related to the speed of a vehicle 10 and / or a request value differential related value relating to a differential value of a request value for the vehicle 10; and a filter processing unit 105 that, when the absolute value of at least one of the speed differential related value and the required value differential related value is equal to or greater than a threshold value, uses a low-pass filter having a larger cutoff frequency than when the at least one absolute value is less than the threshold value to derive a wheel speed detection value on the basis of a value derived by performing a filtering process for removing noise from a wheel speed raw value.

Description

Electronic control unit

[0001] The present invention relates to an electronic control device mounted on a transport device that is driven by the power of a prime mover.

[0002] Patent Literature 1 discloses a control device that estimates the degree of slip of a vehicle's wheels based on the detection value of a wheel speed sensor. The control device obtains a difference between a first wheel speed filtered value calculated by applying a first filter process to the wheel speed detected by the wheel speed sensor, and a second wheel speed filtered value calculated by applying a second filter process to the wheel speed. Both the first filter process and the second filter process are filter processes using low-pass filters. The cutoff frequencies of the low-pass filters used in the first filter process and the second filter process are different. Therefore, when the wheel speed is decreasing, the difference increases as the wheel slip ratio increases. Therefore, the control device can estimate the degree of wheel slip based on the difference.

[0003] JP 2016-182884 A

[0004] A raw value obtained by digitizing a detection signal from a sensor that detects a state quantity of a vehicle, such as a wheel speed sensor, contains noise components. Therefore, a detected state quantity value is generally derived by filtering the raw value. However, when filtering is performed on the raw value, a phase delay occurs due to the filtering, which may cause a discrepancy between the detected state quantity value derived by the control device and the actual value of the state quantity. Note that this problem may also occur when detecting state quantities of transportation equipment other than a vehicle.

[0005] An electronic control device for solving the above problem is a device mounted on a transportation device that is moved by power of a prime mover and includes a sensor for detecting a state quantity of the transportation device, and includes: an acquisition unit that acquires at least one of a speed differential-related value associated with a differential value of a parameter related to the speed of the transportation device and a demand value differential-related value associated with a differential value of a demand value for the transportation device, and a filtering unit that, when an absolute value of at least one of the speed differential-related value and the demand value differential-related value acquired by the acquisition unit is equal to or greater than a threshold, performs filtering using a low-pass filter with a higher cutoff frequency than when the absolute value of at least one of the speed differential-related value and the demand value differential-related value is less than the threshold, to remove noise from raw values ​​that have been digitized from detection signals of the sensor, and derives a detection value of the state quantity based on the value derived.

[0006] The electronic control device has an effect of increasing the accuracy of detecting the state quantities of the transportation equipment.

[0007] FIG. 1 is a schematic diagram showing a vehicle equipped with an electronic control device according to an embodiment. FIG. 2 is a block diagram showing the contents of filtering processing performed by the electronic control device of FIG. 1. FIG. 3 is a flowchart showing a series of processing steps performed by the electronic control device of FIG. 1 when deriving a detected value of wheel speed, which is an example of a detected value of a state quantity. FIG. 4 is a timing chart showing a case where wheel speed decreases due to the generation of braking force. FIG. 5 is a timing chart showing the transition of values ​​derived by executing filtering processing. FIG. 6 is a flowchart showing a part of a modified example of the series of processing steps performed when deriving a detected value of wheel speed, which is an example of a detected value of a state quantity.

[0008] An embodiment of an electronic control device mounted on a transportation device that is driven by the power of a prime mover will be described below with reference to Figures 1 to 5. An example of the transportation device is a vehicle. The vehicle is equipped with at least one of an engine and an electric motor as a prime mover. Hereinafter, the electronic control device will be referred to as an "ECU."

[0009] 1, a vehicle 10 includes at least one wheel 11, a brake operating member 13, friction brakes 20 in the same number as the wheels 11, a brake actuator 30, and an ECU 40. The brake operating member 13 is a member operated by the driver of the vehicle 10 to decelerate the vehicle 10. An example of the brake operating member 13 is a brake pedal.

[0010] <Friction Brake and Brake Actuator> The friction brake 20 includes a wheel cylinder 21, a rotating body 22, and a friction member 23. The rotating body 22 rotates integrally with the wheel 11. A braking force is generated on the wheel 11 by pressing the friction member 23 against the rotating body 22. The hydraulic pressure in the wheel cylinder 21 is referred to as the "wheel pressure Pw." The friction brake 20 is configured such that the force pressing the friction member 23 against the rotating body 22 increases as the wheel pressure Pw increases. Hereinafter, the braking force generated on the wheel 11 by the operation of the friction brake 20 will also be referred to as the "friction braking force."

[0011] The brake actuator 30 is configured to be able to supply brake fluid to the wheel cylinder 21. That is, the brake actuator 30 adjusts the friction braking force generated on the wheel 11 by adjusting the wheel pressure Pw.

[0012] <Sensors provided in the vehicle> The vehicle 10 is provided with at least one state quantity sensor. The state quantity sensor is a sensor that detects a state quantity of the vehicle 10. An example of a state quantity sensor is a wheel speed sensor 51. The wheel speed sensor 51 detects the rotation speed of the wheels 11 as a state quantity of the vehicle 10. The wheel speed sensor 51 outputs, for example, a pulse signal generated in association with the rotation of the wheels 11 as a detection signal to the ECU 40.

[0013] The vehicle 10 is equipped with a brake sensor 53 as a sensor other than the state quantity sensor. The brake sensor 53 detects information related to the operation of the brake operating member 13 by the driver. One example of the brake sensor 53 is a sensor that detects a braking operation amount, which is the amount of operation of the brake operating member 13 by the driver. A detection signal from the brake sensor 53 is output to the ECU 40.

[0014] The brake sensor 53 may be a pedal force sensor that detects the operating force of the brake operating member 13 applied by the driver. <ECU> The ECU 40 controls the brake actuator 30 based on detection signals from the multiple sensors 51, 53. An example of the ECU 40 includes a processing circuit 41. The processing circuit 41 has a CPU 42 and a memory 43. The memory 43 stores a control program executed by the CPU 42.

[0015] The CPU 42 executes the control program in the memory 43, causing the processing circuit 41 to function as a demand value derivation unit 101, an acquisition unit 103, a filter processing unit 105, and a braking control unit 107. The demand value derivation unit 101, the acquisition unit 103, and the filter processing unit 105 are functional units for deriving a wheel speed detection value VWADJ based on the detection signal of the wheel speed sensor 51. The wheel speed detection value VWADJ is an example of a "detected value of a state quantity of the vehicle 10." The braking control unit 107 is a functional unit for operating the braking actuator 30 based on the wheel speed detection value VWADJ.

[0016] Based on the detection signal input from the wheel speed sensor 51 to the ECU 40, the processing circuit 41 derives a raw wheel speed value VWSE, which is a raw value obtained by digitizing the detection signal. The raw wheel speed value VWSE is the wheel speed before execution of a software-based filtering process M10. The filtering process M10 is a process for removing noise components from the input value. During signal detection and during the process of transmitting the signal from the wheel speed sensor 51 to the ECU 40, noise components may be superimposed on the detection signal from the wheel speed sensor 51. In this case, the raw wheel speed value VWSE before execution of the filtering process M10 described above will be a value including noise components.

[0017] <Functional Units> The above-described functional units will be described with reference to Figures 1 and 2. <Required Value Derivation Unit> The required value derivation unit 101 derives a required value for the vehicle 10. The "required value" here refers to a required value of a parameter that can change a state quantity of the vehicle 10. When the state quantity is the wheel speed VW, parameters that can change the wheel speed VW include, for example, the deceleration, acceleration, traveling speed, and braking force of the vehicle 10. In this embodiment, the required value derivation unit 101 derives a required deceleration DVS, which is a required value for the deceleration of the vehicle 10, as the required value. For example, the required value derivation unit 101 derives the required deceleration DVS so that the required deceleration DVS increases as the braking operation amount detected by the brake sensor 53 increases.

[0018] <Acquisition Unit> The acquisition unit 103 acquires a demand value differentiation-related value related to a differentiation value of a demand value for the vehicle 10. In this embodiment, the demand value derivation unit 101 derives the demand deceleration DVS as the demand value. Therefore, the acquisition unit 103 acquires a value related to the differentiation value of the demand deceleration DVS as the demand value differentiation-related value. For example, the acquisition unit 103 acquires a demand jerk DDVS, which is a value obtained by differentiating the demand deceleration DVS once, as the demand value differentiation-related value.

[0019] <Filtering Processor> The filtering process unit 105 derives the detected wheel speed value VWADJ by performing filtering process M10 using a low-pass filter. When the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth, the filtering process unit 105 performs filtering process M10 using a low-pass filter with a higher cutoff frequency than when the absolute value of the required jerk DDVS is less than the threshold value DDVSth, and derives the detected wheel speed value VWADJ based on the value derived by performing filtering process M10 using a low-pass filter with a higher cutoff frequency than when the absolute value of the required jerk DDVS is less than the threshold value DDVSth.

[0020] In this embodiment, the filter processing unit 105 derives the first wheel speed candidate value VWF1 by performing filter processing M10 using a low-pass filter with a first cutoff frequency C1. The filter processing unit 105 also derives the second wheel speed candidate value VWF2 by performing filter processing M10 using a low-pass filter with a second cutoff frequency C2. The second cutoff frequency C2 is greater than the first cutoff frequency C1. When the absolute value of the required jerk DDVS is less than the threshold value DDVSth, the filter processing unit 105 derives the detected wheel speed value VWADJ based on the first wheel speed candidate value VWF1. On the other hand, when the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth, the filter processing unit 105 derives the detected wheel speed value VWADJ based on the second wheel speed candidate value VWF2.

[0021] The threshold value DDVSth is a criterion for determining whether the absolute value of the required jerk DDVS is large, i.e., whether the change in the required value is large. When the change in the required value is large, there is a high possibility that the wheel speed VW will subsequently change significantly. The lower the cutoff frequency of the low-pass filter, the higher the efficiency of removing noise components from the raw wheel speed value VWSE. On the other hand, the lower the cutoff frequency, the lower the responsiveness to changes in the raw wheel speed value VWSE. Therefore, during a transient period when the change in the required value is large during vehicle braking, the filter processing unit 105 acquires a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. On the other hand, when the change in the required value is small during vehicle braking, the filter processing unit 105 acquires a value based on the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ.

[0022] The filter processing M10 will be described with reference to FIG. 2 . The filter processing unit 105 uses a low-pass filter M11 to derive a first processed value VWLP1, which is a value obtained by removing noise components from the raw wheel speed value VWSE, which is a digitized value of the detection signal from the wheel speed sensor 51. Next, the filter processing unit 105 uses a low-pass filter M12, which is the same low-pass filter as used to derive the first processed value VWLP1, to derive a second processed value VWLP2, which is a value obtained by removing noise components from the first processed value VWLP1. That is, the second processed value VWLP2 is a value derived by passing the raw wheel speed value VWSE through the low-pass filter twice.

[0023] The filter processing unit 105 executes a deviation derivation process M13 to derive a difference ΔVWLP between the second processed value VWLP2 and the first processed value VWLP1. The filter processing unit 105 then executes a derivation process M14 to derive a wheel speed candidate value VWF by subtracting the absolute value of the difference ΔVWLP from the first processed value VWLP1. For example, when the cutoff frequencies of the low-pass filters M11 and M12 are set to the first cutoff frequency C1, the wheel speed candidate value VWF derived in the derivation process M14 is the first wheel speed candidate value VWF1. For example, when the cutoff frequencies of the low-pass filters M11 and M12 are set to the second cutoff frequency C2, the wheel speed candidate value VWF derived in the derivation process M14 is the second wheel speed candidate value VWF2.

[0024] 1, the braking control unit 107 operates the braking actuator 30 based on the wheel speed detection value VWADJ when there is a braking request for the vehicle 10. For example, the braking control unit 107 fine-tunes the friction braking force based on the wheel speed detection value VWADJ.

[0025] <Wheel Speed ​​Detection Process> The wheel speed detection process, which is a series of processes executed by the processing circuit 41 when deriving the wheel speed detection value VWADJ, will be described with reference to Fig. 3. The processing circuit 41 repeatedly executes the wheel speed detection process at every predetermined control period.

[0026] In step S11, the processing circuitry 41 derives the first wheel speed candidate value VWF1 by functioning as the filter processing unit 105. In this case, the processing circuitry 41 derives the first wheel speed candidate value VWF1 by performing a filter process M10 using low-pass filters M11 and M12 with a first cutoff frequency C1.

[0027] In the next step S13, the processing circuitry 41 derives the second wheel speed candidate value VWF2 by functioning as the filter processing unit 105. In this case, the processing circuitry 41 derives the second wheel speed candidate value VWF2 by performing a filter process M10 using low-pass filters M11 and M12 with a second cutoff frequency C2.

[0028] In the following step S15, the processing circuit 41 determines whether or not there is a braking request for the vehicle 10. For example, the processing circuit 41 can determine that there is a braking request when the brake operating member 13 is operated. Furthermore, for example, even if the brake operating member 13 is not operated, the processing circuit 41 can determine that there is a braking request when another ECU requests the ECU 40 to decelerate the vehicle 10. If the processing circuit 41 determines that there is a braking request (S15: YES), it proceeds to step S31. On the other hand, if the processing circuit 41 determines that there is no braking request (S15: NO), it proceeds to step S17.

[0029] In step S17, the processing circuit 41 functions as the filter processing unit 105 to set a coefficient α (described later) to 1 and a coefficient β to 0 (zero). In the following step S19, the processing circuit 41 functions as the filter processing unit 105 to set the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. That is, when there is no braking request, the processing circuit 41 derives the detected wheel speed value VWADJ based on the second wheel speed candidate value VWF2. Thereafter, the processing circuit 41 temporarily ends the wheel speed detection process.

[0030] In step S31, the processing circuit 41 derives the required deceleration DVS by functioning as the required value derivation unit 101. In the next step S33, the processing circuit 41 functions as the acquisition unit 103 by functioning as the required jerk DDVS.

[0031] In the following step S35, the processing circuit 41 determines whether at least one of the following conditions is true: immediately after the start of braking; and the absolute value |DDVS| of the requested jerk is equal to or greater than the threshold value DDVSth. When braking force begins to be generated at the wheels 11, the amount of change in the wheel speed VW increases. Therefore, the processing circuit 41 determines that the current state is immediately after the start of braking within a predetermined time period from the time a braking request is generated. If at least one of the following conditions is true: immediately after the start of braking; and the absolute value |DDVS| is equal to or greater than the threshold value DDVSth (YES in S35), the processing circuit 41 proceeds to step S361. On the other hand, if neither the current state is immediately after the start of braking; nor the absolute value |DDVS| is equal to or greater than the threshold value DDVSth (NO in S35), the processing circuit 41 proceeds to step S501.

[0032] In step S361, the processing circuit 41 determines whether the determination in step S35 in the previous control cycle was NO. If the determination in step S35 in the previous control cycle was NO (S361: YES), the processing circuit 41 proceeds to step S362. On the other hand, if the determination in step S35 in the previous control cycle was YES (S361: NO), the processing circuit 41 proceeds to step S37.

[0033] In step S362, the processing circuit 41 functions as the filter processing unit 105, and sets the coefficient α to a value obtained by subtracting the coefficient β from 1. Then, the processing circuit 41 proceeds to step S37.

[0034] In step S37, the processing circuit 41 functions as the filter processing unit 105 and sets the coefficient β to 0 (zero). In the following step S39, the processing circuit 41 functions as the filter processing unit 105 and corrects the coefficient α by increasing it. The coefficient α is a value greater than or equal to 0 (zero) and less than or equal to 1. The processing circuit 41 gradually increases the coefficient α by repeatedly executing the process of step S39.

[0035] Then, in step S41, the processing circuit 41 functions as the filter processing unit 105 to determine whether the coefficient α is less than 1. If the coefficient α is less than 1 (S41: YES), the processing circuit 41 proceeds to step S43. On the other hand, if the coefficient α is 1 or greater (S41: NO), the processing circuit 41 proceeds to step S45.

[0036] In step S43, the processing circuit 41 functions as the filter processing unit 105 to derive the detected wheel speed value VWADJ. At this time, the processing circuit 41 derives the detected wheel speed value VWADJ based on the first wheel speed candidate value VWF1, the second wheel speed candidate value VWF2, and the coefficient α. For example, the processing circuit 41 derives the detected wheel speed value VWADJ using the following relational expression (D1). As a result, the processing circuit 41 repeatedly executes the processes of steps S39 and S43, thereby increasing the coefficient α, and thereby gradually bringing the detected wheel speed value VWADJ closer to the second wheel speed candidate value VWF2.

[0037] VWADJ = α VWF2 + (1 - α) VSF1 (D1) When the coefficient α is greater than 0 and less than 1, the processing circuit 41 derives the detected wheel speed value VWADJ based on both the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. In other words, when the coefficient α is greater than 0 and less than 1, the processing circuit 41 derives a mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. After deriving the detected wheel speed value VWADJ in step S43, the processing circuit 41 temporarily ends the wheel speed detection process.

[0038] In step S45, the processing circuit 41 functions as the filter processing unit 105 to set the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. That is, when the absolute value |DDVS| of the required jerk is equal to or greater than the threshold value DDVSth (S35: YES), the processing circuit 41 derives the detected wheel speed value VWADJ based on at least the second wheel speed candidate value VWF2 of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. Thereafter, the processing circuit 41 temporarily ends the wheel speed detection process.

[0039] In step S501, the processing circuit 41 determines whether the determination in step S35 in the previous control cycle was YES. If the determination in step S35 in the previous control cycle was YES (S502: YES), the processing circuit 41 proceeds to step S502. On the other hand, if the determination in step S35 in the previous control cycle was NO (S501: NO), the processing circuit 41 proceeds to step S51.

[0040] In step S502, the processing circuit 41 functions as the filter processing unit 105, and sets the coefficient β to a value obtained by subtracting the coefficient α from 1. Then, the processing circuit 41 proceeds to step S51.

[0041] In step S51, the processing circuit 41 functions as the filter processing unit 105 and sets the coefficient α to 0 (zero). In the following step S53, the processing circuit 41 functions as the filter processing unit 105 and corrects the coefficient β by increasing it. The coefficient β is a value greater than or equal to 0 (zero) and less than or equal to 1. The processing circuit 41 gradually increases the coefficient β by repeatedly executing the process of step S53.

[0042] Then, in step S55, the processing circuitry 41 functions as the filter processing unit 105 to determine whether the coefficient β is less than 1. If the coefficient β is less than 1 (S55: YES), the processing circuitry 41 proceeds to step S57. On the other hand, if the coefficient β is 1 or greater (S55: NO), the processing circuitry 41 proceeds to step S59.

[0043] In step S57, the processing circuit 41 functions as the filter processing unit 105 to derive the detected wheel speed value VWADJ. At this time, the processing circuit 41 derives the detected wheel speed value VWADJ based on the first wheel speed candidate value VWF1, the second wheel speed candidate value VWF2, and the coefficient β. For example, the processing circuit 41 derives the detected wheel speed value VWADJ using the following relational expression (D2). As a result, the processing circuit 41 repeatedly executes the processes of steps S53 and S57, thereby increasing the coefficient β, and thereby gradually bringing the detected wheel speed value VWADJ closer to the first wheel speed candidate value VWF1.

[0044] VWADJ = β VWF1 + (1 - β) VSF2 (D2) When the coefficient β is greater than 0 and less than 1, the processing circuit 41 derives the detected wheel speed value VWADJ based on both the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. In other words, when the coefficient β is greater than 0 and less than 1, the processing circuit 41 derives a mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. After deriving the detected wheel speed value VWADJ in step S57, the processing circuit 41 temporarily ends the wheel speed detection process.

[0045] In step S59, the processing circuit 41 functions as the filter processing unit 105 to set the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ. That is, when the absolute value |DDVS| of the required jerk is less than the threshold value DDVSth (S35: NO), the processing circuit 41 derives the detected wheel speed value VWADJ based on at least the first wheel speed candidate value VWF1 of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. Thereafter, the processing circuit 41 temporarily ends the wheel speed detection process.

[0046] <Actions and Effects of the Present Embodiment> The actions and effects of the present embodiment will be described with reference to Figures 4 and 5. In the example shown in Figure 4, a braking request is issued to the vehicle 10 at timing t10 ​​while the vehicle 10 is traveling. Then, the brake actuator 30 is activated, causing a frictional braking force to be generated in the wheels 11. Therefore, the wheel speed VW starts to decrease shortly after timing t10.

[0047] As shown in (A), (B), (C), and (D) in FIG. 4, no braking request is issued before timing t10. Therefore, the processing circuit 41 derives the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. When a braking request is issued at timing t10, the processing circuit 41 determines that braking has just started, and therefore derives the detected wheel speed value VWADJ based on the second wheel speed candidate value VWF2. Specifically, before timing t10, the second wheel speed candidate value VWF2 was derived as the detected wheel speed value VWADJ. Therefore, even after timing t10, the processing circuit 41 continues to derive the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ.

[0048] When a braking request is issued, the absolute value of the required jerk DDVS increases. Then, during the period from timing t11 to timing t12, the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth. Therefore, the processing circuit 41 derives the detected wheel speed value VWADJ based on the second wheel speed candidate value VWF2. Specifically, the processing circuit 41 derives the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ.

[0049] After time t12, when the wheel speed VW is decreasing due to the generation of frictional braking force, the absolute value of the required jerk DDVS becomes less than the threshold value DDVSth. Then, the processing circuit 41 derives the detected wheel speed value VWADJ based on the first wheel speed candidate value VWF1. Specifically, the processing circuit 41 derives the detected wheel speed value VWADJ using the above-described relational expression (D2). That is, the processing circuit 41 derives the mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. From time t12 onward, the coefficient β gradually increases from 0 (zero). Therefore, the detected wheel speed value VWADJ derived using the above-described relational expression (D2) gradually approaches the first wheel speed candidate value VWF1.

[0050] Then, at timing t13, the coefficient β exceeds 1, so the processing circuit 41 derives the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ. At timing t14, just before the rotation of the wheel 11 stops, the absolute value of the required jerk DDVS becomes equal to or greater than the threshold value DDVSth. Therefore, from timing t14 onward, the processing circuit 41 derives the detected wheel speed value VWADJ based on the second wheel speed candidate value VWF2. Specifically, the processing circuit 41 derives the detected wheel speed value VWADJ using the above-described relational expression (D1). That is, the processing circuit 41 derives the mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. From timing t14 onward, the coefficient α gradually increases from 0 (zero). Therefore, the detected wheel speed value VWADJ derived using the above relational expression (D1) gradually approaches the second wheel speed candidate value VWF2.

[0051] In the example shown in FIG. 4 , at timing t15 when the detected wheel speed value VWADJ is approaching the second wheel speed candidate value VWF2, the absolute value of the required jerk DDVS becomes less than the threshold value DDVSth. Therefore, after timing t15, the processing circuit 41 derives the detected wheel speed value VWADJ using the relational expression (D2). That is, the processing circuit 41 derives the detected wheel speed value VWADJ as a mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. From timing t15, the coefficient β gradually increases. Therefore, the detected wheel speed value VWADJ derived using the relational expression (D2) gradually approaches the first wheel speed candidate value VWF1.

[0052] Then, at timing t16, the coefficient β exceeds 1, so the processing circuit 41 derives the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ. Here, with reference to FIGS. 5A and 5B, a first comparative example will be described in which the first wheel speed candidate value VWF1 is derived as the detected wheel speed value VWADJ even when the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth. FIG. 5B is an enlarged view of the portion surrounded by the dashed line in FIG. 5A.

[0053] The detected wheel speed value VWADJ indicated by the solid line in FIGS. 5A and 5B is equal to the first wheel speed candidate value VWF1. The lower the cutoff frequency of the low-pass filters M11 and M12, the higher the efficiency of noise removal from the raw wheel speed value VWSE. Therefore, when the change in the wheel speed VW is small, the detected wheel speed value VWADJ is less likely to deviate from the raw wheel speed value VWSE. On the other hand, the lower the cutoff frequency, the lower the responsiveness of the detected wheel speed value VWADJ to changes in the raw wheel speed value VWSE. Therefore, as shown in FIG. 5B, during periods when the change in the wheel speed VW is large, the phase lag of the detected wheel speed value VWADJ relative to the actual value of the wheel speed VW is likely to be large.

[0054] In this regard, the ECU 40 derives a second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ during a period in which the change in the wheel speed VW is large during vehicle braking. The second wheel speed candidate value VWF2 is a value derived by performing a filter process M10 using low-pass filters M11 and M12 with a second cutoff frequency C2. The second cutoff frequency C2 is higher than the first cutoff frequency C1. Therefore, compared to the first comparative example, the ECU 40 can reduce the phase lag of the detected wheel speed value VWADJ relative to the actual value of the wheel speed VW during a period in which the change in the wheel speed VW is large.

[0055] On the other hand, during a period in which the change in the wheel speed VW is not large, the detected wheel speed value VWADJ is derived based on the first wheel speed candidate value VWF1, thereby enabling the ECU 40 to derive the detected wheel speed value VWADJ from which noise components have been appropriately removed during a period in which the change in the wheel speed VW is not large.

[0056] Therefore, the ECU 40 can derive the wheel speed detection value VWADJ with less phase delay due to the execution of the filter processing M10 while removing noise components. In this embodiment, the following effects can be further obtained.

[0057] (1) When the vehicle is braked, as the required deceleration DVS increases, the braking force also increases. As a result, the amount of decrease in the wheel speed VW also increases. At this time, a time lag occurs between the start of change in the required deceleration DVS and the start of change in the wheel speed VW. Therefore, when the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth, the ECU 40 derives a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. As a result, when the wheel speed VW begins to change due to an increase in braking force, the ECU 40 can derive a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. Therefore, when the wheel speed VW begins to decrease in response to a braking request, the ECU 40 can more effectively suppress the occurrence of a phase lag in the detected wheel speed value VWADJ relative to the actual value of the wheel speed VW.

[0058] (2) In the filter process M10, the ECU 40 subtracts the absolute value of the difference ΔVWLP from the first processed value VWLP1 to derive the wheel speed candidate value VWF. The difference ΔVWLP is the difference between the second processed value VWLP2 and the first processed value VWLP1. This difference ΔVWLP is approximately equal to the difference between the actual wheel speed VW and the first processed value VWLP1. Therefore, by subtracting the absolute value of the difference ΔVWLP from the first processed value VWLP1 to derive the wheel speed candidate value VWF, the ECU 40 can accurately calculate the detected wheel speed value VWADJ.

[0059] (3) Consider a second comparative example in which, when the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth, only the second wheel speed candidate value VWF2 is derived from the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. In this case, in the second comparative example, when the absolute value |DDVS| is less than the threshold value DDVSth, only the first wheel speed candidate value VWF1 is derived from the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. In this second comparative example, immediately after switching from a first state in which the absolute value |DDVS| is less than the threshold value DDVSth to a second state in which the absolute value |DDVS| is equal to or greater than the threshold value DDVSth, a mixed value of the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 cannot be derived as the detected wheel speed value VWADJ. This may result in variations in the detected wheel speed value VWADJ. Similarly, even immediately after switching from the second state to the first state, the mixed value cannot be derived as the detected wheel speed value VWADJ, and therefore the detected wheel speed value VWADJ may vary.

[0060] In this regard, in the present embodiment, the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2 are derived regardless of whether the absolute value |DDVS| is equal to or greater than the threshold value DDVSth. Therefore, the ECU 40 can derive the mixed value as the detected wheel speed value VWADJ immediately after switching from the first state to the second state and immediately after switching from the second state to the first state. Therefore, the ECU 40 can suppress variations in the detected wheel speed value VWADJ immediately after switching from the first state to the second state and immediately after switching from the second state to the first state.

[0061] <Modifications> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0062] The ECU 40 may obtain a value obtained by differentiating the required deceleration DVS twice as the required value differentiation-related value. In this case, if the absolute value of the required value differentiation-related value is equal to or greater than a threshold value, the ECU 40 may derive a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ.

[0063] The ECU 40 may obtain, as the required value differentiation-related value, a value obtained by differentiating a required value other than the required deceleration DVS. For example, the ECU 40 may obtain, as the required value differentiation-related value, a value obtained by differentiating the braking operation amount once or a value obtained by differentiating the braking operation amount twice.

[0064] The ECU 40 may acquire a speed differential-related value related to a differential value of the detected wheel speed value VWADJ. For example, the ECU 40 may acquire a value obtained by differentiating the detected wheel speed value VWADJ once as the speed differential-related value, or may acquire a value obtained by differentiating the detected wheel speed value VWADJ twice as the speed differential-related value. If the absolute value of the speed differential-related value is equal to or greater than a threshold value, the ECU 40 may acquire a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ.

[0065] As shown in FIG. 6 , when the processing circuit 41 determines in step S15 shown in FIG. 3 that a braking request is present (S15: YES), the processing circuit 41 proceeds to step S133. In step S133, the processing circuit 41 functions as the acquisition unit 103 to acquire a speed differential-related value related to the differential value of the detected wheel speed value VWADJ. For example, the processing circuit 41 acquires a value obtained by differentiating the detected wheel speed value VWADJ twice as the speed differential-related value DDVW. In the next step S135, the processing circuit 41 determines whether the absolute value of the speed differential-related value DDVW is equal to or greater than a threshold value DDVWth. The threshold value DDVWth is a criterion for determining whether the change in the detected wheel speed value VWADJ is large. When the processing circuit 41 determines that the absolute value of the speed differential-related value DDVW is equal to or greater than the threshold value DDVWth (S135: YES), the processing circuit 41 proceeds to step S37. On the other hand, when the processing circuit 41 determines that the absolute value of the speed differential related value DDVW is less than the threshold value DDVWth (S135: NO), the processing circuit 41 proceeds to the above-mentioned step S51.

[0066] - The processing circuit 41 may obtain a value based on the second wheel speed candidate value VWF2 as the wheel speed detection value VWADJ when at least one of the following conditions is true: the absolute value of the required jerk DDVS is greater than or equal to the threshold value DDVSth, and the absolute value of the speed differential related value is greater than or equal to the threshold value.

[0067] When the processing circuit 41 determines that there is no braking request (S15: NO), the processing circuit 41 may derive the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ. The wheel speed detection process shown in FIG. 3 may be a process in which the determination of step S15 is omitted. In this case, even when the vehicle 10 is accelerated in accordance with an acceleration request of the vehicle 10, the processing circuit 41 may derive a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ when the absolute value of the request value derivative-related value is equal to or greater than a threshold value. Furthermore, when the vehicle 10 is accelerated in accordance with an acceleration request of the vehicle 10, the processing circuit 41 may derive a value based on the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ when the absolute value of the request value derivative-related value is less than a threshold value.

[0068] In this case, the processing circuit 41 may derive the difference between the first processing value VWLP1 and the difference ΔVWLP as the wheel speed candidate value VWF in the derivation process M14 shown in Fig. 2. When the absolute value of the required jerk DDVS is equal to or greater than the threshold value DDVSth, the processing circuit 41 may derive only the second wheel speed candidate value VWF2 from the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. Furthermore, when the absolute value |DDVS| is less than the threshold value DDVSth, the processing circuit 41 may derive only the first wheel speed candidate value VWF1 from the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2.

[0069] In this case, when the absolute value |DDVS| is equal to or greater than the threshold value DDVSth, the processing circuit 41 may derive the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. Furthermore, when the first wheel speed candidate value VWF1 immediately before the absolute value |DDVS| becomes equal to or greater than the threshold value DDVSth is set as the first reference value, the processing circuit 41 may derive the detected wheel speed value VWADJ based on the first reference value and the second wheel speed candidate value VWF2 immediately after the absolute value |DDVS| becomes equal to or greater than the threshold value DDVSth. For example, the processing circuit 41 may substitute the first reference value for "VWF1" in the above relational expression (D1).

[0070] On the other hand, when the absolute value |DDVS| is less than the threshold value DDVSth, the processing circuit 41 may derive the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ. Furthermore, when the second wheel speed candidate value VWF2 immediately before the absolute value |DDVS| becomes less than the threshold value DDVSth is set as the second reference value, the processing circuit 41 may derive the detected wheel speed value VWADJ based on the second reference value and the first wheel speed candidate value VWF1 immediately after the absolute value |DDVS| becomes less than the threshold value DDVSth. For example, the processing circuit 41 may substitute the second reference value for "VWF2" in the above relational expression (D2).

[0071] The processing circuit 41 may derive the third wheel speed candidate value VWF3 by performing a filter process M10 using a low-pass filter with a third cutoff frequency C3 in addition to the first wheel speed candidate value VWF1 and the second wheel speed candidate value VWF2. The third cutoff frequency C3 is a frequency higher than the second cutoff frequency C2. In this case, a first threshold value and a second threshold value lower than the first threshold value may be set as threshold values. As a result, when the absolute value of the required jerk DDVS is equal to or greater than the first threshold value, the processing circuit 41 derives a value based on the third wheel speed candidate value VWF3 as the detected wheel speed value VWADJ. When the absolute value of the required jerk DDVS is less than the first threshold value and equal to or greater than the second threshold value, the processing circuit 41 derives a value based on the second wheel speed candidate value VWF2 as the detected wheel speed value VWADJ. When the absolute value of the required jerk DDVS is less than the second threshold value, the processing circuit 41 derives a value based on the first wheel speed candidate value VWF1 as the detected wheel speed value VWADJ.

[0072] The filtering process may be a process different from that shown in Fig. 2. For example, the filtering process may be a process in which the raw wheel speed value VWSE is passed through a low-pass filter only once to obtain a value as the candidate wheel speed value.

[0073] The sensor may be any sensor other than the wheel speed sensor 51 that detects the rotation speed of a rotating member. For example, an example of the other sensor is a sensor that detects the rotation of an output shaft of an electric motor mounted on the vehicle.

[0074] The state quantity sensor may be a sensor other than the wheel speed sensor 51 as long as it can detect the state quantity of the vehicle 10. Examples of such a sensor include an acceleration sensor that detects acceleration and a yaw rate sensor that detects yaw rate. For example, in the case of a yaw rate sensor, the ECU 40 performs processing equivalent to the method described in the above embodiment to calculate the detected value of the yaw rate as the state quantity detection value.

[0075] The ECU may be an ECU that controls an on-board actuator other than the brake actuator 30. The ECU 40 may be configured as a circuit including one or more processors operating according to a computer program, one or more dedicated hardware circuits such as dedicated hardware that executes at least some of the various processes, or a combination thereof. Examples of dedicated hardware include an application-specific integrated circuit (ASIC). The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., storage medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0076] Other Technical Ideas The following describes technical ideas that can be understood from the above-described embodiment and modified examples. [Supplementary Note 1] It is preferable that the acquisition unit acquires, as the speed differential related value, a value obtained by first differentiating the speed of the transport equipment or a correlation value of the speed.

[0077] [Supplementary Note 2] The acquisition unit preferably acquires, as the speed differential related value, a value obtained by twice differentiating the speed of the transport equipment or a correlation value of the speed. [Supplementary Note 3] The acquisition unit preferably acquires, as the speed differential related value, a value obtained by once differentiating the request value.

[0078] [Supplementary Note 4] It is preferable that the acquisition unit acquires a value obtained by differentiating the requirement value twice as the requirement value differential-related value. Note that the expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

Claims

1. An electronic control device mounted on transportation equipment that is equipped with a sensor for detecting a state quantity of the transportation equipment that moves by the power of a prime mover, the electronic control device comprising: an acquisition unit that acquires at least one of a speed differential-related value associated with a differential value of a parameter related to the speed of the transportation equipment and a demand value differential-related value associated with a differential value of a demand value for the transportation equipment; and a filter processing unit that, when the absolute value of at least one of the speed differential-related value and the demand value differential-related value acquired by the acquisition unit is equal to or greater than a threshold, performs filtering processing to remove noise from raw values ​​that have been digitized from detection signals of the sensor, using a low-pass filter with a higher cutoff frequency compared to when the absolute value of at least one of the speed differential-related value and the demand value differential-related value acquired by the acquisition unit is less than the threshold, and derives a detection value of the state quantity based on the value derived.

2. The electronic control device according to claim 1, wherein, in the filter processing, the filter processing unit derives a first processed value that removes noise components from the raw value using the low-pass filter, derives a second processed value that removes noise components from the first processed value using the low-pass filter used to derive the first processed value, and derives a value obtained by subtracting from the first processed value the absolute value of the difference between the second processed value and the first processed value as the detected value of the state quantity.

Images