JP2012168605A - Control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus which prevents continuity of control from being deteriorated when switching calculation means.SOLUTION: A control apparatus comprises: first calculation means that performs calculation for equipment control based on an input signal; second calculation means that performs the same calculation; determination means that determines whether or not the first calculation means functions properly; selection means that performs switching to output the result of the calculation performed by the first calculation means as the control signal when the first calculation means is determined as functioning properly by the determination means, and the result of the calculation performed by the second calculation means as the control signal when the first calculation means is determined as not functioning properly; and storage means that stores the difference between the results of the calculations performed for the same input signal by the first calculation means and the second calculation means at a predetermined timing. When the result of the calculation by the second calculation means is output as the control signal, the result of the calculation by the second calculation means is compensated by using the difference stored by the storage means.

Description

  The present invention relates to a control device that performs a calculation for device control based on an input signal and outputs a calculation result as a control signal.

  2. Description of the Related Art Conventionally, control devices for performing device control have been widely used in moving bodies such as vehicles and facilities such as plants. In control devices that perform such device control, there is a high demand for control reliability. Therefore, many CPUs and other calculation means are multiplexed in preparation for a failure of a CPU that performs calculations.

  Multiplexing of arithmetic means can be realized by, for example, a multi-core processor in which a plurality of CPU cores are enclosed in the same chip. Further, a multiprocessor device including a plurality of computers themselves may be used. Further, in the case where a plurality of arithmetic units such as an ALU (Arithmetic Logic Unit) and an FPGA (Field Programmable Gate Array) are provided, a configuration may be adopted in which the arithmetic units used for the calculation are switched.

  Patent Document 1 describes a duplex control method that realizes such multiplexing. In this method, if a failure is detected during processing in the main system, the process is continued by switching to the standby system.

  In order to keep the contents of the storage units of both systems the same, the write contents generated in the main system storage unit are sequentially stored in the internal buffer by the storage control unit operating independently of the main system CPU, In response to an instruction from the system CPU, the storage unit change contents of the main CPU are started to be stored in another buffer area, and in parallel, changes according to the contents of the buffer area are made to the backup system storage unit.

JP 07-218902 A

  By the way, various input signals are input from a sensor, a switch, or the like to a control device that performs control for device control. This input signal includes an analog signal that represents a numerical value or the like by fluctuations in the voltage value or current value in the communication line, and the environment such as the magnetic field and temperature around the control device, the characteristics of the communication line, and the acceleration given to the control device. The voltage value and the current value may be changed to affect the input signal.

  In a control device in which arithmetic means are multiplexed, the influence on the input signal as described above may be different for each arithmetic means due to the arrangement of the arithmetic means and the length of the communication line. For this reason, a phenomenon may occur in which the input signals of the same eyelid are recognized as different numerical values or the like by each calculation means.

  If each input means recognizes the same input signal as a different numerical value, the result of each calculation will be different. As a result, there are cases where the control signals output from the respective arithmetic means are deviated. When the control signals output by the respective arithmetic means are different, the continuity of control when the arithmetic operation of a certain arithmetic means is replaced by another arithmetic means or when the alternative processing returns to the original state. May be damaged. Thus, for example, in the case of a control device that performs motor control, the torque output by the motor does not change smoothly, which may cause unnecessary vibrations.

  The method described in Patent Document 1 does not consider such a phenomenon at all. Therefore, when the processing is switched from the main system to the standby system or vice versa, the continuity of control may be impaired.

  The present invention is intended to solve such problems, and a main object thereof is to provide a control device capable of preventing the continuity of control from being impaired when switching computing means.

In order to achieve the above object, one embodiment of the present invention provides:
A control device that performs calculation for device control based on an input signal and outputs a calculation result as a control signal,
First computing means for performing computation for the device control based on the input signal;
Second computing means for performing computation for device control based on the input signal;
Determining means for determining whether or not the first calculating means is functioning normally;
When the determination means determines that the first calculation means is functioning normally, the calculation result of the first calculation means is output as the control signal, and the determination means outputs the first calculation means. Selecting means for switching so as to output the calculation result of the second calculation means as the control signal when it is determined that is not functioning normally;
Storage means for storing a difference between results obtained by performing the same calculation result on the same input signal by the first calculation means and the second calculation means at a predetermined timing;
When the calculation result of the second calculation means is output as the control signal, the calculation result of the second calculation means is corrected using the difference stored in the storage means. ,
It is a control device.

  According to this aspect of the present invention, there is provided storage means for storing a difference between results obtained when the first calculation means and the second calculation means perform the same calculation result on the same input signal at a predetermined timing. And when the calculation result of the second calculation means is output as a control signal, the calculation result of the second calculation means is stored in the storage means. Since the difference is corrected using the difference, the continuity of control can be prevented from being impaired when the calculation means is switched.

In one embodiment of the present invention,
The determination result by the determination unit is determined when an event indicating that an abnormality has occurred in the first calculation unit continues for a predetermined period of time,
The selecting means activates the second computing means and starts a normal operation state from a sleep state before an elapse of the predetermined period when an event indicating that an abnormality has occurred in the first computing means has occurred. It is preferable to shift to the above.

  In this way, it is possible to avoid the inconvenience that the processing shift is delayed depending on the time required for starting the second arithmetic means. As a result, the process can be shifted without delay when an abnormality occurs in the first calculation means.

  ADVANTAGE OF THE INVENTION According to this invention, when switching a calculating means, the control apparatus which can be made not to impair the continuity of control can be provided.

1 is a system configuration example of a hybrid ECU 1 according to a first embodiment of the present invention. It is a figure which shows a mode that the state of the main computer 10 or the subcomputer 20 is switched by the power supply IC30. It is a figure which shows typically transition of the calculation result of each computer at the time of abnormality occurrence of the main computer. It is a flowchart which shows the flow of the process performed by hybrid ECU1 of a present Example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  Hereinafter, a control apparatus according to an embodiment of the present invention will be described with reference to the drawings. The control device of the present invention is a device for performing device control in a moving body such as a vehicle or a facility such as a plant. The following description will be made assuming that the present invention is applied to a hybrid ECU (Electronic Control Unit) that is mainly mounted on a hybrid vehicle and calculates a torque command value of a motor based on an input signal input from an in-vehicle sensor or the like. Note that the ECU is a computer unit configured to perform specific control.

<First embodiment>
[Constitution]
FIG. 1 is a system configuration example of a hybrid ECU 1 according to a first embodiment of the present invention. The hybrid ECU 1 includes a main computer 10, a sub computer 20, a power supply IC 30, and a shared memory 40 as main components.

  Various input signals are input to the hybrid ECU 1 from the in-vehicle sensor. For example, the accelerator position signal AC from the accelerator position sensor, the shift position signal SP from the shift position sensor, the engine speed Ne from the engine ECU, the vehicle speed signal V from the vehicle speed sensor, and the charging rate of the hybrid battery from the battery ECU Each SOC is input. These signals may be digital signals or analog signals.

  Each of the main computer 10 and the sub computer 20 includes a program memory such as a ROM (Read Only Memory), a CPU (Central Processing Unit), a RAM (Random Access Memory), and an A / D for converting an analog signal into a digital signal. A converter is provided. Each CPU includes an instruction fetch unit, an instruction buffer, an instruction decoder, an arithmetic circuit such as an ALU (Arithmetic Logic Unit) and an FPGA (Field Programmable Gate Array), an LSU (Load Store Unit), a register, a cache memory, and a flash memory. Etc. are provided.

  Note that such a configuration is a representative example of a control device including “a plurality of arithmetic units”, and the control device of the present invention may employ various types of computers such as a multi-core processor and a multi-processor device.

  In the present embodiment, while the main computer 10 is functioning normally, the main computer 10 calculates a motor torque command value and outputs it to the motor ECU 50. However, when an abnormality occurs in the main computer 10, the sub computer 20 performs the same calculation as that of the main computer 10 and outputs it to the motor ECU 50. As a configuration for this purpose, the same program (there may be slightly different parts depending on the specifications of the computer) may be stored in the program memory of the main computer 10 and the sub computer 20, or the main computer 10 and the sub computer 20 may be stored. May share the program memory.

[Torque command value calculation]
Here, the motor torque command value calculation executed with the main computer 10 as the main system and the sub computer 20 as the standby system will be briefly described. The vehicle on which the hybrid ECU 1 of this embodiment is mounted is a series / parallel (split) hybrid vehicle in which an engine, a first motor, a second motor, and an axle are connected by a planetary gear.

  In this configuration, the rotation shaft of the first motor is connected to the sun gear, which is the central member of the planetary gear, via the sun gear shaft. The rotating gear of the second motor is connected to the ring gear of the planetary gear via a ring gear shaft and a reduction gear, and the axle is further connected via a ring gear shaft and a gear mechanism.

  And the crankshaft of an engine is connected with the carrier which connected several pinion gears via a damper. In addition, since the various things etc. are already well-known about the principle of the power split by such a planetary gear, detailed description is abbreviate | omitted.

  The first motor and the second motor are connected to a hybrid battery such as a lithium ion battery. The hybrid battery is charged by performing regenerative control in the first motor or the second motor, and supplies power to these when power running control is performed in the first motor or the second motor.

  The main computer 10 (or the sub computer 20; hereinafter omitted), the driver requested torque Td requested by the driver to be output by the accelerator operation based on the accelerator opening AC, the shift position SP signal, the vehicle speed V, and the like input as described above. # Is calculated, and this is multiplied by the rotational speed Nd of the drive shaft and a predetermined coefficient to calculate the driver required power Pd. The rotational speed Nd of the drive shaft is calculated based on a value from a rotation sensor (resolver) attached to the second motor, for example.

  Then, an output request Pw is calculated by adding the driver request power Pd and the auxiliary machine request Pa (electric power required by an electric air compressor or other electric equipment not directly related to traveling) input from the outside.

  When the output request Pw is less than the suppliable power Pb (calculated from the SOC or the like) of the hybrid battery, the vehicle travels only by the power of the second motor (motor travel). In this case, a value obtained by dividing the driver required torque Td # by the gear ratio of the gear mechanism is the required torque Tm # of the second motor 130. The output request Pw may be compared with a predetermined threshold value instead of the suppliable power Pb of the hybrid battery.

  On the other hand, when the output request Pw is greater than or equal to the suppliable power Pb of the hybrid battery, the engine, the first motor, and the second motor are driven to travel (engine / motor traveling). In this case, first, the required engine power Pe is calculated by subtracting the suppliable power Pb of the hybrid battery from the output request Pw. The coordinates of the point at which the engine required power Pe can be realized on the operation line (the coordinate of the torque and the rotation speed as elements) can be obtained by using the engine target torque Te # and the target The rotation speed is Ne #.

  For the first motor, the target rotational speed Ng # is calculated based on the following equation (1) from the target rotational speed Ne # of the engine and the current rotational speed Nr of the ring gear. In the equation, ρ is the gear ratio of the planetary gear.

  Ng # = {(1 + ρ) · Ne # −Nr} / ρ (1)

  Then, feedback control of the following equation (2) is performed so that the first motor is driven at the rotation speed Ng #. In the equation, Ng is the actual rotational speed of the first motor. K1 is the gain of the proportional term, and K2 is the gain of the integral term.

  Tg # = previous Tg # + K1 · (Ng # −Ng) + K2 · ∫ (Ng # −Ng) dt (2)

  When the target torque Tg # of the first motor is determined, the torque output to the ring gear by driving the engine and the first motor (hereinafter referred to as direct torque Tor) is calculated by the following equation (3), and the driver required torque Td The target torque Tm # of the second motor 130 is calculated by dividing the torque obtained by subtracting the direct torque Ter from # by the gear ratio of the gear mechanism.

  Ter = −Tg # / ρ (3)

  When the main computer 10 calculates the target rotational speed Ne # and target torque Te # of the engine, the target rotational speed Ng # and target torque Tg # of the first motor, and the target torque Tm # of the second motor in this manner, A control signal expressed as a digital value or an analog value is output to the engine ECU or the motor ECU 50.

[Computer switching control]
The power supply IC 30 includes a WDT (Watchdog Timer) 32 for determining whether or not the main computer 10 is functioning normally. The WDT 32 monitors whether or not a predetermined signal is periodically output by the main computer 10 and outputs an abnormality detection signal indicating that to the power supply IC 30 when the predetermined signal is interrupted.

  Based on the abnormality detection signal output by the WDT 32, the power supply IC 30 selects and switches the state of the main computer 10 or the sub computer 20 from sleep, normal operation state, and the like.

  FIG. 2 is a diagram illustrating a state in which the state of the main computer 10 and the sub computer 20 is switched by the power supply IC 30.

  For example, in the steady state (time t0 to t1 in FIG. 2), the power supply IC 30 sets the main computer 10 to the normal operation state and the sub computer 20 to the sleep state, and the WDT 32 starts outputting an abnormality detection signal (time t1) A wake-up signal is output to the sub computer 20 to be activated.

  When the WDT 32 continuously outputs the abnormality detection signal for a predetermined cycle or more (time t2), it is determined that the main computer 10 is in an abnormal state, and a reset signal is output to the main computer 10 and the sub computer. 20 causes the main computer 10 to execute an alternative process.

  As described above, since the sub computer 20 is activated before the determination that the main computer 10 is in an abnormal state is determined, the inconvenience that the processing shift is delayed depending on the time required for the activation of the sub computer 20 is avoided. Can do. As a result, the process can be shifted without delay when an abnormality occurs in the main computer 10.

  Thereafter, when the reset process of the main computer 10 is completed, the main computer 10 notifies the sub computer 20 by an interrupt notification or the like (time t3), and the sub computer 20 ends the alternative process when receiving the interrupt notification. Then, the sleep state is entered (time t4).

[Correction of calculation result difference]
By the way, in such a configuration, even when the calculation is performed using the same calculation formula based on the output value of the same sensor, the calculation results of the main computer 10 and the sub computer 20 may be different. As described above, the signal input to the hybrid ECU 1 may be a digital signal or an analog signal. In particular, in the case of an analog signal, the difference between the magnetic field inside and outside the hybrid ECU 1 and the wiring length is different. This is because the main computer 10 and the sub computer 20 may be recognized as different values due to a temperature change or the like.

  In response to such a phenomenon, the hybrid ECU 1 of the present embodiment learns the divergence of the calculation results generated as a result of performing the same calculation result on the same input signal as the source, and the sub computer 20 replaces the main computer 10. When performing, the correction was made so as to cancel the learned deviation.

  Specifically, the hybrid ECU 1 determines that the main computer 10 and the sub computer 20 have the same source signal (actual signal or dummy signal) at a predetermined timing (for example, every time the vehicle starts, etc.). A signal may be output), and the same calculation result is performed, and either the main computer 10 or the sub computer 20 calculates a difference between the calculation results and stores it in the shared memory 40. Here, the difference is, for example, (calculation result of the main computer 10) − (calculation result of the sub computer 20).

  As described above, when the sub computer 20 performs the substitute process of the main computer 10, the difference stored in the shared memory 40 is added to the calculation result of the sub computer 20 and is output to the motor ECU 50. In addition, what is necessary is just to subtract a difference and to output to motor ECU50, when a difference is said reciprocal number.

  The shared memory 40 is, for example, a RAM. However, when the difference calculation interval is set to a plurality of trips, it is preferable to use a nonvolatile memory such as an EEPROM (Electrically Erasable and Programmable Read Only Memory).

  FIG. 3 is a diagram schematically showing the transition of the calculation result of each computer when an abnormality occurs in the main computer 10.

  As shown in the figure, when an abnormality occurs in the main computer 10, the sub computer 20 that has been activated in advance calculates a torque command value and outputs it to the motor ECU 50. Here, the sub computer 20 outputs a torque command value corrected by adding a difference stored in advance in the shared memory 40 to its own calculated value to the motor ECU 50. In addition, the inconvenience that a gap occurs in the torque command value at the end can be suppressed.

  When returning from the subcomputer 20 to the main computer 10, it is preferable that the calculation result of the subcomputer 20 is transmitted to the main computer 10 and used as original data for an annealing process or the like. The same can be said when the sub computer 20 starts the substitute process. In this case, the calculation result of the main computer 10 may be transmitted to the sub computer 20 between the times t1 and t2 in FIG.

  FIG. 4 is a flowchart showing a flow of processing executed by the hybrid ECU 1 of the present embodiment. This flow is repeatedly executed at a predetermined cycle while the vehicle on which the hybrid ECU 1 is mounted is started.

  First, the main computer 10 determines whether or not it is a difference learning timing (S100). The difference learning timing may be set to a desired timing, and can be set, for example, at the start of the vehicle, every predetermined time, every predetermined number of days, every predetermined week, or the like.

  If it is determined that the timing is the difference learning timing, a wake-up signal is output to the sub computer 20 to start the sub computer 20 (S102), and the same input as that of the main computer 10 is synchronized with the sub computer 20 with the timing synchronized. The same calculation result for the signal is output (S104), the difference is calculated and stored in the shared memory 40 (S106).

  Then, the sub computer 20 is instructed to shift to the sleep state (S108).

  The power supply IC 30 determines whether or not the WDT 32 has output an abnormality detection signal (S110). If it is determined that the WDT 32 has not output an abnormality detection signal, a count value described later is set to 0 (S112), and one routine of this flow is terminated.

  If it is determined that the WDT 32 has output an abnormality detection signal, it is determined whether or not the sub computer 20 is in a sleep state (S114). Such a determination is made, for example, by storing the state of the subcomputer 20 in a register or the like built in the power supply IC 30 and referring to the state information.

  If it is determined that the sub computer 20 is not in the sleep state, a wake-up signal is output to the sub computer 20 to start the sub computer 20 and enter a normal operation state (S116).

  Then, it is determined whether or not the count value is greater than or equal to a predetermined value C1 (for example, a value of about 5) (S118). This count value is a value that determines a period until the determination that the main computer 10 is in an abnormal state is confirmed, and is counted by an increment counter built in the power supply IC 30. A decrement counter may be used. In this case, the determination in S116 is replaced with “determining whether the count value is equal to or less than a predetermined value”.

  When it is determined that the count value is equal to or greater than the predetermined value C1, a reset signal is output to the main computer 10 (S120), and the sub computer 20 is caused to execute an alternative process of the main computer 10 (S122). Then, the count value is reset (S124), and one routine of this flow is terminated.

  If the count value is less than the predetermined value, the count value is incremented by 1 (S126), and one routine of this flow is terminated.

  According to the hybrid ECU 1 of the present embodiment described above, control continuity is not impaired when the computer that calculates the torque command value is switched from the main computer 10 to the sub computer 20 (and vice versa). be able to.

<Second embodiment>
Hereinafter, the hybrid ECU 2 according to the second embodiment of the present invention will be described. Since the configuration is the same as that of the first embodiment, reference will be made to FIG. 1 and description of each component will be omitted.

  The main computer 10 included in the hybrid ECU 2 of the second embodiment calculates in advance an average value of changes in several change patterns such as when the torque command value increases or decreases, and stores it in the shared memory 40. Keep it. Then, when performing the substitution process, the sub computer 20 calculates the torque command value by taking into account the change pattern stored in the shared memory 40 based on the torque command value output immediately before by the main computer 10.

  According to the hybrid ECU 2 of the present embodiment described above, the control continuity is not impaired when the computer that calculates the torque command value is switched from the main computer 10 to the sub computer 20 (and vice versa). be able to.

  The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. And substitutions can be added.

  For example, the control device of the invention is not limited to a hybrid ECU mounted on a hybrid vehicle, and can be widely applied to devices for performing device control in a moving body such as a vehicle or equipment such as a plant.

  Further, the difference between the calculation results of the main computer 10 and the sub computer 20 is not limited to the shared memory 40 as in the embodiment, but may be a RAM, a flash memory, or the like included in the sub computer 20.

1, 2 Hybrid ECU
10 Main computer 20 Sub computer 30 Power supply IC
32 WDT
40 shared memory 50 motor ECU

Claims (2)

A control device that performs calculation for device control based on an input signal and outputs a calculation result as a control signal,
First computing means for performing computation for the device control based on the input signal;
Second computing means for performing computation for device control based on the input signal;
Determining means for determining whether or not the first calculating means is functioning normally;
When the determination means determines that the first calculation means is functioning normally, the calculation result of the first calculation means is output as the control signal, and the determination means outputs the first calculation means. Selecting means for switching so as to output the calculation result of the second calculation means as the control signal when it is determined that is not functioning normally;
Storage means for storing a difference between results obtained by performing the same calculation result on the same input signal by the first calculation means and the second calculation means at a predetermined timing;
When the calculation result of the second calculation means is output as the control signal, the calculation result of the second calculation means is corrected using the difference stored in the storage means. ,
Control device. The control device according to claim 1,
The determination result by the determination unit is determined when an event indicating that an abnormality has occurred in the first calculation unit continues for a predetermined period of time,
The selecting means activates the second computing means and starts a normal operation state from a sleep state before an elapse of the predetermined period when an event indicating that an abnormality has occurred in the first computing means has occurred. It is characterized by shifting to
Control device.

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