JP2000289545A - Vehicular control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular control device capable of eliminating interference between the signals received by a radio receiver and higher harmonic components of clock signals of an electronic control unit and keeping the period of control of the control unit constant. SOLUTION: A clock signal frequency fCLK is set at 20 or 21 KHz according to the reception frequency fRCV of a radio receiver so that noises are not generated in the signals received by the radio. To change the frequency fCLK from 20 KHz to 21 KHz, a control flow that does not contain a WAIT instruction is switched to a control flow that contains a WAIT instruction (S15-S17). To change the frequency fCLK from 21 KHz to 20 KHz, the control flow containing the WAIT instruction is switched to the control flow that does not contain the WAIT instruction (S18-S20).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle for controlling an internal combustion engine and power steering mounted on a vehicle, and more particularly to a control device for a vehicle having a radio receiver.

[0002]

2. Description of the Related Art If the harmonic frequency of a clock signal of a microcomputer is near the frequency of a radio wave received by a radio receiver, the noise of the radio receiver increases and the S / N of the received signal deteriorates. In such a case, a radio receiver in which the frequency of the clock signal is changed has been conventionally used (Japanese Patent Laid-Open No. 5-63592).

An electric motor used for power steering mounted on a vehicle is a PWM (Pulse Width Modulati).
On) a control device driven by a signal is known that changes the frequency of the PWM signal when the harmonic frequency of the PWM signal is near the reception frequency of the radio receiver (particularly, the control device is not particularly limited). Kaihei 10-327597).

[0004]

However, when an electronic control unit having a microcomputer controls, for example, electric power steering, the frequency of a clock signal is changed according to the reception frequency of a radio wave. , That is, the update cycle of the motor drive signal changes, and the steering feeling of the steering changes.

The present invention has been made in view of this point, and eliminates interference between a received signal of a radio receiver and a harmonic component of a clock signal of an electronic control unit.
It is an object of the present invention to provide a vehicle control device that can maintain a constant control cycle of an electronic control unit.

[0006]

According to one aspect of the present invention, there is provided a control apparatus for a vehicle having a radio receiver, comprising: an electronic control unit operating in synchronization with a clock signal; In the vehicle control device comprising, while changing the frequency of the clock signal according to the frequency of the radio wave being received by the radio receiver, when the clock signal frequency is changed in the increasing direction, the electronic control unit of It is characterized in that a standby command for waiting for a predetermined time during a control cycle is inserted.

Here, the predetermined time is set so that the control cycle before the change of the clock signal frequency is substantially the same as the control cycle after the change of the clock signal frequency. According to this configuration, the frequency of the clock signal of the electronic control unit is changed in accordance with the frequency of the radio wave being received by the radio receiver, and when the clock signal frequency is changed in the increasing direction, the frequency of the electronic control unit is changed. Since the standby command for waiting for a predetermined time is inserted during the control cycle, the execution cycle of the control step by the electronic control unit is shortened by the increase of the clock frequency, but almost the same as before the clock frequency was increased by the insertion of the standby command. The control period can be set, for example, when the electric power steering is controlled, the steering feeling can be prevented from changing.

The clock signal frequency is changed to a first frequency (for example, 20
KHz) and a second frequency higher than the first frequency (for example, 21 KHz), the electronic control unit sets the clock signal frequency to the first frequency when the clock signal frequency is set to the first frequency. When the control is performed according to a control flow that does not include a wait instruction (WAIT instruction) to cause a standby, and the clock signal frequency is set to the second frequency, the control may be performed according to a control flow that includes the standby instruction. desirable. More generally, when the clock signal frequency is changed in the increasing direction, a standby command to wait for a predetermined time during the control cycle of the electronic control unit is inserted, and when the clock signal frequency is changed in the decreasing direction, the electronic control unit is controlled. It is desirable to delete the wait instruction inserted during the control cycle of the unit.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of a vehicle control device according to an embodiment of the present invention. This device comprises an electronic control unit (hereinafter referred to as “ECU”) 1, 2, 3, and a tuner 4 as a radio receiver.
And three antennas 1, 2 and
The tuner 3 and the tuner 4 are connected via a communication bus 6. The ECU 1 is a control unit that controls the electric power steering of the vehicle. The ECU 2 is a control unit that controls the automatic transmission of the vehicle.
Is a control unit for controlling the internal combustion engine of the vehicle.

As shown in FIG. 2, the ECUs 1, 2, and 3 each include a central processing unit (CPU) 11, a memory 12 for storing programs to be executed by the CPU 11 and data in the middle of calculations, and a sensor attached to a control target. Circuit 13 for inputting signals from a switch or a switch, an output circuit 14 for supplying a drive signal to a motor or a solenoid valve to be controlled, CP
A clock signal generation circuit 15 for generating a clock signal of U11, a communication interface 16 for controlling communication via the communication bus 6, and the like are provided. The clock signal generation circuit 15 outputs the frequency fCLK of the clock signal to the CP
20KHz and 21KH according to the control signal from U11
and z can be changed.

The tuner 4 sends tuning information TUNE indicating the frequency of a radio broadcast wave being received to the ECU 1,
Supply to a few. FIG. 3 (a) shows the spectrum of a broadcast radio wave, which is 558 KHz, 567 KHz and 576 KHz.
Hz indicates that a broadcast wave exists.

Here, the tuner 4 is, for example, 558 kHz.
Is being received, the CPU 11 of each ECU
Controls the clock generation circuit 15 so that the clock signal frequency fCLK becomes 21 KHz. As a result, the harmonic components of the clock signal in the broadcast reception band are
As shown in (c), the frequency becomes 567 KHz and 588 KHz, and the frequency becomes sufficiently far from 558 KHz during reception, so that a good reception signal can be obtained without causing noise of the radio reception signal.

If the reception frequency of the tuner 4 is, for example, 5
When the frequency is 67 KHz, the CPU 11
Controls the clock generation circuit 15 so that the clock signal frequency fCLK becomes 20 KHz. As a result, the harmonic components of the clock signal in the broadcast reception band are
As shown in (b), the frequency becomes 560 KHz and 580 KHz, which is a frequency sufficiently separated from 567 KHz during reception, so that a good reception signal can be obtained without causing noise of the radio reception signal.

FIG. 4 is a flowchart of a clock frequency fCLK setting process executed by the CPU 11 of the ECUs 1 to 3. This process is executed, for example, at regular intervals. In step S11, it is determined whether or not the tuner 4 is receiving a radio broadcast. If not, the process is immediately terminated. In this case, the clock frequency up to that time is maintained.

When a radio broadcast is being received, the reception frequency fRCV is read from the tuning information TUNE (step S12), and a target clock frequency f1 is set according to the reception frequency fRCV (step S1).
3). This setting corresponds to the reception frequency fRCV as described above.
Based on the harmonic frequency fRH20 in the reception band when the clock frequency is set to 20 KHz and the harmonic frequency fRH21 in the reception band when the clock frequency is set to 21 KHz, The clock frequency corresponding to the wave frequency fRH20 or fRH21 is set to the target clock frequency f1 (20 kHz).
Or 21 KHz).

In step S14, it is determined whether or not the target clock frequency f1 is 21 KHz.
Hz, the clock frequency fCLK at that time
Is determined to be 21 KHz (step S1).
5). When fCLK = 21 KHz, the frequency may be maintained as it is, so that the process is immediately terminated, and
When fCLK = 20 KHz, control is executed based on a control flow including a WAIT instruction (standby instruction), that is, switching from a control flow not including a WAIT instruction to a control flow including a WAIT instruction (step S16). Then, the clock frequency fCLK is set to 21 KHz (step S17), and this processing ends.

Here, the wait time (predetermined time) TWAIT generated by the WAIT instruction is set as follows. That is, a control cycle (for example, an update cycle of a motor drive signal) T21W when the control is executed based on the control flow including the WAIT instruction with the clock frequency fCLK = 21 KHz, and the WAI with the fCLK = 20 KHz
The standby time TWAIT is set so that the control cycle T20 when the control is executed based on the control flow that does not include the T command is substantially equal to the control cycle. The control flow including the WAIT instruction is the same as the control flow not including the WAIT instruction except for the WAIT instruction. The WAIT instruction is composed of a timer or a step that does nothing.

On the other hand, if the target clock frequency f1 is not 21 KHz in step S14, that is, f1 = 20KH
If it is z, it is determined whether or not the clock frequency fCLK at that time is 20 KHz (step S1).
8). When fCLK = 20 KHz, the frequency may be maintained as it is, so the processing is immediately terminated, and
When fCLK = 21 KHz, the control is executed based on the control flow not including the WAIT instruction, that is, from the control flow including the WAIT instruction to the WAI.
Switching to control flow not including T instruction (step S1)
9) The clock frequency fCLK is set to 20 KHz (step S20), and the process ends.

As described above, according to the processing of FIG. 4, when the clock frequency fCLK is increased from 20 KHz to 21 KHz, the control flow including the WAIT instruction does not include the WIT instruction.
The control flow is switched to the control flow including the AIT instruction, and the clock frequency fCLK is changed from 21 kHz to 20 kHz.
When the clock frequency fCLK is changed to the control flow including the WAIT command, the control flow is switched from the control flow including the WAIT command to the control flow not including the WAIT command. For example, a situation in which the operation feeling of the electric power steering changes can be avoided.

The present invention is not limited to the embodiment described above, and various modifications are possible. For example, in the embodiment described above, the clock signal frequency fCLK is 20K
Hz or 21 KHz, but is not limited to this. For example, a radio reception frequency fRCV
May be set to any of 19 KHz, 20 KHz or 21 KHz. In that case,
A control flow including a WAIT instruction for the first waiting time TW1, and a second waiting time TW longer than the first waiting time TW1
2 and a control flow not including a wait instruction, and a clock signal frequency fCLK =
When the frequency is set to 19 kHz, a control flow not including the WAIT instruction is used. When the frequency fCLK is set to 20 kHz,
When using the control follow including the WAIT instruction for the first standby time and fCLK = 21 KHz, the control follow including the WAIT instruction for the second standby time may be used. The same applies to the case where the clock signal frequency fCLK is changed to four or more.

In the above-described embodiment, the control device has three ECUs. However, the number of ECUs is not limited to three, but may be any number. Further, the clock signal generation circuit 15
Although an example has been described in which each of the CUs is provided, the output of one clock signal generation circuit may be supplied to a plurality of ECUs.

[0022]

As described above in detail, according to the present invention, the frequency of the clock signal of the electronic control unit is changed and the frequency of the clock signal is increased according to the frequency of the radio wave being received by the radio receiver. When you change the direction,
Since the instruction to wait for a predetermined time is inserted during the control cycle of the electronic control unit, the execution cycle of the control step by the electronic control unit is shortened by increasing the clock frequency, but before the clock frequency is increased by inserting the standby instruction. The control cycle can be set to be substantially the same, and for example, when controlling the electric power steering, the steering feeling can be prevented from changing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a vehicle control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an electronic control unit shown in FIG.

FIG. 3 is a diagram for explaining a relationship between a reception frequency of a radio receiver and a clock signal frequency.

FIG. 4 is a flowchart of a clock signal frequency setting process executed by a CPU shown in FIG. 2;

[Explanation of symbols]

 1, 2, 3 Electronic control unit 4 Radio receiver 5 Antenna 6 Communication bus 11 CPU

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Susumu Ota 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 5K052 AA02 BB04 DD02 DD23 FF26 GG03

Claims (1)

[Claims] 1. A control device for a vehicle provided with a radio receiver, comprising: an electronic control unit operating in synchronization with a clock signal, wherein a frequency of a radio wave being received by the radio receiver is provided. And changing a frequency of the clock signal in accordance with the following, and when the clock signal frequency is changed in an increasing direction, inserting a standby command to wait for a predetermined time during a control cycle of the electronic control unit. Control device.