JP5974990B2 - Solenoid control device - Google Patents

Description

  The present invention relates to a solenoid control device that controls driving of a solenoid by controlling an energization current to the solenoid.

  The solenoid control device is configured to include a switching element disposed between the solenoid and the power source, and by energizing the solenoid by changing a duty ratio that is a ratio between a pulse on time and a pulse off time of the switching element. It is common to control the current. As described in the following patent document, the duty ratio is controlled based on the deviation between the target duty ratio and the actual duty ratio obtained by converting the current that actually flows through the solenoid into the duty ratio. Control may be performed. When acquiring the actual duty ratio, the duty ratio of the switching element and the current flowing through the solenoid obtained under the set conditions (for example, at the reference temperature and the power supply voltage is the reference voltage). Map data indicating the relationship is used.

JP 2010-245282 A JP 2010-199438 A

  When acquiring the relationship between the duty ratio and the current, naturally, only the current corresponding to the duty ratio of 100% can be acquired. That is, the map data indicating the relationship between the duty ratio and the current only exists up to a duty ratio of 100%. However, for example, for a certain duty ratio, the current flowing through the solenoid increases as the temperature decreases and the voltage of the power source increases. Since the relationship between the duty ratio and the current is under a set condition, the current that actually flows through the solenoid may exceed the current corresponding to the duty ratio of 100% in the map data. It is.

  In the device described in Patent Document 2, when the current that actually flows through the solenoid exceeds the current that corresponds to the duty ratio of 100% in the map data, the current that actually flows through the solenoid is converted into the duty ratio. The duty ratio is set to 100%. That is, even if a large current actually flows through the solenoid, there is a possibility that feedback is not properly performed. Specifically, in such a case, a large current continues to flow. This invention is made | formed in view of such a situation, and makes it a subject to perform appropriate feedback and to optimize the electric current which flows into a solenoid.

  In order to solve the above-described problems, the solenoid control device of the present invention includes: (a) an actual current that is a current that actually flows through the solenoid by a controller that controls the energization current to the solenoid by controlling the duty ratio of the switching element; (B) an actual duty ratio acquisition unit that acquires an actual duty ratio that is a duty ratio converted from the actual current, and (c) a target duty that is a duty ratio that is a control target of the switching element. A target duty ratio determining unit for determining a ratio, and configured to feedback control the duty ratio of the switching element based on a deviation between the target duty ratio and the actual duty ratio, and the controller further includes ( d) Indicates the relationship between the duty ratio of the switching element and the current flowing through the solenoid under the set conditions (I) when the actual current is equal to or less than the upper limit current corresponding to the duty ratio of 100% in the map data, based on the map data, The actual duty ratio is obtained, and (ii) when the actual current exceeds the upper limit current, the actual duty ratio is obtained based on a function that approximates the relationship between the duty ratio and the current. .

  The solenoid control device of the present invention uses a function that approximates the relationship between the duty ratio and the current even when the actual current is larger than the upper limit current that is the current corresponding to the duty ratio of 100% in the map data. Thus, the large actual current can be virtually converted into a duty ratio exceeding 100%. That is, the solenoid control device of the present invention is configured such that a value exceeding 100% is fed back as an actual duty ratio. Therefore, according to the solenoid control device of the present invention, as described above, even when the current flowing through the solenoid exceeds the upper limit current, appropriate feedback is performed and the current flowing through the solenoid is suppressed to an appropriate magnitude. It is possible.

  In the “map data” in the solenoid control device of the present invention, the relationship between the duty ratio and the current under the set conditions is, for example, that at a standard temperature and the power supply voltage is constant at a certain value. It can be adopted. That is, while changing the duty ratio of the switching element in advance, the current for each of the duty ratio is actually measured, and a plurality of data represented by the duty ratio and the current corresponding thereto is adopted as map data. be able to.

  The “actual duty ratio acquisition unit” in the solenoid device of the present invention acquires the actual duty ratio based on the map data when the actual current is less than or equal to the upper limit current. At that time, various interpolation is performed using the map data. The actual duty ratio can be obtained by the method. Note that the relationship between the duty ratio of the switching element and the current flowing through the solenoid has a substantially linear characteristic in many ranges, so if linear interpolation is used as the interpolation method, a value that is relatively close to the actual value by a simple method. Can be calculated.

  In addition, the “function that approximates the relationship between the duty ratio and the current” used when the actual current exceeds the upper limit current by the actual duty ratio acquisition unit may be any order function. However, since the relationship between the duty ratio of the switching element and the current flowing through the solenoid has a substantially linear characteristic in many ranges, the actual duty ratio is obtained based on a linear line that approximates the relationship between the duty ratio and the current. It can be constituted as follows. For example, the approximate straight line can be obtained from a plurality of data constituting the map data by a known method such as a least square method. Then, by storing the obtained slope and intercept of the approximate straight line, the actual duty ratio exceeding 100% can be converted to the actual current exceeding the upper limit current.

1 is a circuit diagram of a vehicle brake system including a solenoid control device according to an embodiment of the claimable invention. FIG. It is a block diagram which shows the function of the brake electronic control unit which manages control of the brake system for vehicles of FIG. (a) It is a circuit diagram of the drive circuit contained in the brake electronic control unit shown in FIG. (b) It is a figure which shows the change of the electric current in the drive circuit of Fig.3 (a). 4 is a graph showing the relationship between the duty ratio of the switching element and the current flowing through the solenoid in the drive circuit of FIG. 3A, and a straight line approximating the relationship. It is a control block diagram which shows typically the action | operation of the said brake electronic control unit. It is a flowchart showing the actual duty ratio acquisition program performed by the brake electronic control unit of FIG.

  Hereinafter, as an embodiment for carrying out the present invention, an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following Example, It can implement in the various aspect which gave various change and improvement based on the knowledge of those skilled in the art.

  FIG. 1 shows a circuit diagram of a vehicle brake system including a solenoid control device 10 which is an embodiment of the claimable invention. The vehicle brake system includes a plurality of solenoid valves having solenoids, and the solenoid control device 10 of the present embodiment controls each solenoid 12 (see FIG. 2) of the plurality of solenoid valves. More specifically, a plurality of solenoid valves provided in the vehicle brake system are provided between the common passage 20 and each of the four brake cylinders 22 to adjust the hydraulic pressures of the four brake cylinders 22. The four holding valves 24 and the four pressure reducing valves 26, the regulator cut valve 32 for connecting or blocking the regulator 30 and the common passage 20, and the master cut valve for connecting or blocking the master cylinder 40 and the common passage 20. 42, a simulator cut valve 52 for allowing or prohibiting the inflow of hydraulic fluid to the stroke simulator 50, a pressure-increasing linear valve 62 for controlling the inflow of hydraulic fluid from the power hydraulic pressure source device 60 to the common passage 20, A pressure reducing linear valve 66 that controls the outflow of hydraulic fluid to the reservoir 64 of the passage 20 is provided in the common passage 20. A communication valve 68 for connecting and disconnecting the parts corresponding to the parts and the right wheel corresponding to the wheel.

  The vehicle brake system is provided with a brake electronic control unit 100 (hereinafter also referred to as “ECU 100”). The ECU 100 is a control device that controls the operation of the various solenoid valves 24, 26, 32, 42, 52, 62, 64, 66, and controls the hydraulic pressure of the hydraulic fluid that acts on the brake cylinder 22 of each brake device. It is. As shown in FIG. 2, the ECU 100 includes a controller 102 mainly composed of a computer having a CPU, a ROM, a RAM, and the like, and various electromagnetic valves 24, 26, 32, 42, 52, 62, 66 and 68. And a plurality of drive circuits 104, 106, 108, 110, 112, 114, 116, 118 corresponding to. A battery 120 as a power source is connected to the plurality of drive circuits 104 and the like, and power is supplied from the battery 120 to various electromagnetic valves 104 and the like.

  Further, the controller 102 is connected to the plurality of drive circuits 104 and the like, and the controller 102 transmits each control signal to the plurality of drive circuits 104 and the like. Specifically, the controller 102 transmits current control signals for opening and closing the electromagnetic valves to the drive circuits 110 and 112 of the master cut valve 42 and the simulator cut valve 52, and the pressure increasing linear valve 62 and the pressure reducing linear valve. 66, the current control signal for controlling the magnetic force generated by the solenoid 12 of each of the linear valves 62 and 66 is transmitted to the drive circuits 114 and 116, and the drive circuits 104 and 106 of the holding valve 24 and the pressure reducing valve 26 are transmitted. Transmits a current control signal for controlling the opening / closing time of various solenoid valves. The current control signal is in accordance with the duty ratio of the switching element, and energization control to the solenoid 12 included in each solenoid valve 24 and the like will be described in detail later.

  Since the drive circuits 104, 106, 108, 110, 112, 114, 116, 118 are all similar in configuration, the drive circuit 114 corresponding to the pressure-increasing linear valve 62 will be described as a representative of those configurations. To do. As shown in FIG. 3A, the drive circuit 114 is configured by connecting a battery 120, a solenoid (solenoid coil) 12, and a switching element 130 in series. The resistor 132 equivalently represents the resistance of the entire drive circuit 114 including the solenoid 12, the switching element 130, and the like. The switching element 130 can be, for example, a transistor, and by controlling the duty, the voltage applied to the solenoid 12 is controlled, and the current flowing through the solenoid 12 is controlled. The drive circuit 114 is provided with a current monitor 134 that detects an actual current that actually flows through the solenoid 12.

In the control circuit of FIG. 3A, the following equation holds.
u (t) = R · i (t) + L · di (t) / dt
Here, u (t) is a voltage applied to the solenoid 12 by duty control of the switching element 130, and i (t) is a current flowing through the solenoid 12. L is the inductance of the solenoid 12, and R is the resistance value of the entire drive circuit 114. When the above equation is Laplace transformed (d / dt = s), the following equation is obtained.
I (s) = {1 / (L · s + R)} · U (s)
As shown in this equation, the transfer function between the voltage (duty ratio) and the current is expressed by a first-order lag response equation. As shown in FIG. 3B, the current value increases with a delay with respect to the change of the duty ratio (transiently), and thereafter (steadily) with a constant magnitude determined by the duty ratio and the resistance value. Become.

  Further, the ECU 100 has a storage unit 140 as shown in FIG. 2, and stores a program that will be described in detail later, map data shown in FIG. The map data shown in FIG. 4 shows the relationship between the duty ratio of the switching element 130 and the current flowing through the solenoid 12 under the condition that the standard temperature T [° C.] and the power supply voltage is the set voltage E [V]. 1 is a map of previously acquired data. More specifically, under the above conditions, control is performed while changing the duty ratio D of the switching element 130 to obtain a current value I having a constant magnitude with respect to each duty ratio D, and the map data is As shown in FIG. 4, the data consists of a plurality of data composed of the duty ratio D and current I.

  Hereinafter, the energization control to the solenoid 12 will be described in detail with reference to the control block diagram of FIG. First, the target current calculation unit 150 determines a target current Iref that is a target value of a current supplied to the solenoid 12 such as each solenoid valve 24. Although a detailed description is omitted, for example, the target hydraulic pressure of the common passage 20 is obtained so that the target current of the pressure-increasing linear valve 62 and the pressure-reducing linear valve 66 becomes a braking force according to the driver's brake operation. The actual hydraulic pressure is determined to be the target hydraulic pressure. Next, in the target duty ratio determination unit 152, the duty ratio Dn for controlling the switching element 130 is determined by linear interpolation based on the map data stored in the storage unit 140 and the target current Iref. Is output.

  Subsequently, in the temperature corresponding correction unit 154, the target duty ratio Dn determined by the target duty ratio determination unit 152 is corrected using the temperature correction coefficient KT and output (duty ratio Dout). The power supply voltage correction unit 156 corrects and outputs the input duty ratio Dout based on the voltage level of the battery 120 (Dout1). When the power supply voltage is low, the input duty ratio Dout is corrected to be larger than when the power supply voltage is high. The relationship between the power supply voltage and the correction value of the duty ratio is acquired in advance, and is mapped and stored, for example. Furthermore, in the noise removal unit 158, when the input duty ratio Dout1 is not between the lower limit value (for example, 0) and the upper limit value (for example, 100%), The lower limit value or the upper limit value is determined and output (Dout2).

  The switching element control unit 160 controls the switching element 130 with the input duty ratio Dout2. By controlling the switching element 130 with the duty ratio Dout2, a current corresponding to the solenoid 12 is supplied.

  The actual current (actual current) flowing through the solenoid 12 is detected by the current monitor 134 and fed back. The actual current Ia (analog value) detected by the current monitor 134 is converted into a digital value by the A / D converter 162 and output, and the current monitor corrector 164 corrects the temperature of the current monitor 134. Or digital values are converted to current values. Further, in the digital filter 166, noise and the like are removed and smoothed. In this embodiment, the moving average value is acquired and output (Iaf).

  In the actual duty ratio acquisition unit 168, the input actual current Iaf is converted into an actual duty ratio Daf. The solenoid control device 10 of this embodiment is characterized by a method for converting the actual current into the duty ratio, and the conversion method will be described in detail later. Then, a deviation ΔD (= Dn−Daf) that is a difference between the actual duty ratio Daf and the target duty ratio Dn is acquired and supplied to the PID control unit 326. In the PID control unit 170, the feedback control value DFB is acquired so that the deviation ΔD of the duty ratio becomes small. Then, it is added to the duty ratio Dout output from the temperature correspondence correction unit 154.

  Since the output value Dout of the temperature corresponding correction unit 154 is the feedforward control value DFF (Dout = DFF), the duty ratio input to the duty control unit 160 is the sum of the feedforward control value and the feedback control value. Therefore, the switching element 130 is controlled by combining the feedforward control and the feedback control.

  Next, the conversion method of the actual current into the duty ratio in the actual duty ratio acquisition unit 168 will be described in detail. Conversion of the actual current to the duty ratio is performed by executing an actual duty ratio acquisition program whose flowchart is shown in FIG. In this actual duty ratio acquisition program, first, in step 1 (hereinafter, step is abbreviated as “S”), the actual current Iaf is acquired. In S2, it is determined whether or not the acquired actual current Iaf is larger than an upper limit current Ilimit that is a current corresponding to a duty ratio of 100% in the map data.

  When the actual current Iaf is less than or equal to the upper limit current Ilimit, the actual duty ratio Daf is acquired by linear interpolation based on the map data shown in FIG. 4 in S3. On the other hand, when the actual current Iaf is larger than the upper limit current Ilimit, the actual duty ratio Daf is acquired based on a straight line that approximates the relationship between the duty ratio and the current shown in the map data in S4. Specifically, the slope α and the intercept β of an approximate line (regression line) D = α · I + β (two-dot chain line in FIG. 4) obtained by the least square method based on a plurality of data constituting the map data are , Stored in the storage unit 140. Based on the linear function, the actual duty ratio Daf corresponding to the actual current Iaf that is larger than the upper limit current Ilimit is acquired. That is, by using the approximate straight line, the actual current Iaf larger than the upper limit current Ilimit is converted into an actual duty ratio Daf exceeding 100%. This is the end of the actual duty ratio acquisition program.

  In the solenoid control device 10 of the present embodiment by the control as described above, a value exceeding 100% is fed back as the actual duty ratio. Therefore, when the actual current Iaf larger than the upper limit current Ilimit flows to the solenoid 12. Even if it exists, appropriate feedback is performed and the electric current which flows through the solenoid 12 can be made into an appropriate magnitude | size. Further, when the actual current Iaf is less than or equal to the upper limit current Ilimit, the solenoid control device 10 according to the present embodiment obtains the actual duty ratio Daf by linear interpolation. Therefore, appropriate feedback is performed rather than acquiring the actual duty ratio using an approximate line.

  The solenoid control device 10 according to the present embodiment includes a drive circuit including a switching element 130 and a controller 102 that controls the drive circuit. The controller 102 also acquires an actual current acquisition unit 170 that acquires the current that actually flows through the solenoid 12 from the detection result of the current monitor 134, and an actual duty ratio acquisition unit that acquires an actual duty ratio obtained by converting the actual current into a duty ratio. 168, a target duty ratio determination unit 152 that determines the target duty ratio, and a storage unit 140 that stores map data indicating the relationship between the duty ratio and the current under the set conditions. Further, the actual current acquisition unit 170 includes a part for executing S1 of the actual duty ratio acquisition program, and the actual duty ratio acquisition unit 168 includes a part for executing S2 to S4 of the actual duty ratio acquisition program. It consists of

  10: Solenoid control device 12: Solenoid 24: Holding valve 26: Pressure reducing valve 32: Regulator cut valve 42: Master cut valve 52: Simulator cut valve 62: Linear valve for pressure increase 66: Linear valve for pressure increase 68: Communication valve 100: Brake Electronic control unit [ECU] 102: Controllers 104 to 116: Drive circuit 120: Battery [power source] 130: Switching element 134: Current monitor 140: Storage unit 152: Target duty ratio determination unit 168: Actual duty ratio acquisition unit 170: Actual Current acquisition unit

Claims (1)

A solenoid control device comprising: a switching element disposed between a solenoid and a power source; and a controller for controlling a current supplied to the solenoid by controlling a duty ratio of the switching element, and controlling driving of the solenoid. Because
The controller is
(a) an actual current acquisition unit that acquires an actual current that actually flows through the solenoid; (b) an actual duty ratio acquisition unit that acquires an actual duty ratio that is a duty ratio converted from the actual current; ) A target duty ratio determining unit that determines a target duty ratio that is a duty ratio to be a control target of the switching element, and based on a deviation between the target duty ratio and the actual duty ratio, the duty ratio of the switching element Configured to feedback control,
The controller
A storage unit for storing map data indicating a relationship between a duty ratio of the switching element and a current flowing through the solenoid under a set condition;
The actual duty ratio acquisition unit
(i) When the actual current is equal to or less than an upper limit current that is a current corresponding to a duty ratio of 100% in the map data, the actual duty ratio is acquired based on the map data, and (ii) the actual A solenoid control device configured to acquire the actual duty ratio based on a function that approximates the relationship between a duty ratio and a current when the current exceeds the upper limit current.

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