Communication system

Patent metadata

Field	Value
Publication number	US-2016355211-A1
Application number	US-201615173117-A
Country	US
Kind code	A1
Filing date	Jun 3, 2016
Priority date	Jun 8, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A communication system includes a sensor apparatus transmitting a sensor signal including detection information of a detection target as a digital signal and a microcomputer receiving the sensor signal through a signal line and performing a control operation at a predetermined operation cycle based on the sensor signal that is received. The microcomputer transmits, to the sensor apparatus, a synchronization signal which is synchronized with the predetermined operation cycle of the microcomputer. The sensor apparatus transmits the sensor signal at a predetermined constant cycle except when the synchronization signal transmitted by the microcomputer is received. The sensor apparatus changes a transmission timing of the sensor signal corresponding to the synchronization signal when the synchronization signal transmitted by the microcomputer is received.

First claim

What is claimed is:

1 . A communication system comprising:
a sensor apparatus transmitting a sensor signal including detection information of a detection target as a digital signal; and a microcomputer receiving the sensor signal through a signal line and performing a control operation at a predetermined operation cycle based on the sensor signal that is received, wherein the microcomputer transmits, to the sensor apparatus, a synchronization signal which is synchronized with the predetermined operation cycle of the microcomputer, the sensor apparatus transmits the sensor signal at a predetermined constant cycle except when the synchronization signal transmitted by the microcomputer is received, and the sensor apparatus changes a transmission timing of the sensor signal corresponding to the synchronization signal when the synchronization signal transmitted by the microcomputer is received.

2 . The communication system according to claim 1 , further comprising:
a power supply circuit supplying a power voltage to the sensor apparatus, wherein the microcomputer and the power supply circuit configure a control apparatus, the sensor apparatus is connected with the control apparatus through the signal line, a reference voltage line, and a power supply line, and the power supply circuit supplies the power voltage to the sensor apparatus through the power supply line.

3 . The communication system according to claim 2 , wherein
the microcomputer transmits the synchronization signal to the sensor apparatus through the signal line.

4 . The communication system according to claim 3 , wherein
the sensor apparatus includes a timer which determines the transmission timing of the sensor signal corresponding to a counting value, and the sensor apparatus changes the transmission timing of the sensor signal determined by the timer so that a transmission cycle shift caused by the timer is corrected.

5 . The communication system according to claim 3 , wherein
the microcomputer outputs the synchronization signal at a time interval which is equal to a predetermined number of transmission cycles of the sensor signal.

6 . The communication system according to claim 5 , wherein,
after the microcomputer is activated, the microcomputer continuously outputs the synchronization signal until a time point at which the sensor signal being transmitted during an activation operation of the microcomputer is ended.

7 . The communication system according to claim 2 , wherein
the microcomputer controls an output of the power supply circuit, the output of the power supply circuit is transmitted to the sensor apparatus through the power supply line, and the microcomputer transmits the output of the power supply circuit as the synchronization signal.

8 . The communication system according to claim 7 , wherein
the microcomputer outputs the synchronization signal by changing a power voltage value supplied by the power supply circuit or by switching a power voltage supply state between a start state and a stop state.

9 . The communication system according to claim 2 , further comprising:
one or more sensor apparatus in addition to the sensor apparatus, wherein the sensor apparatus and the one or more sensor apparatus are connected to the control apparatus through respective signal lines, respective reference voltage lines, and respective power supply lines.

10 . The communication system according to claim 9 , wherein
the microcomputer outputs the synchronization signal so that transmission timings of sensor signals transmitted from the sensor apparatus and the one or more sensor apparatus are different from one another.

11 . The communication system according to claim 10 , wherein
the microcomputer sets power supply timings from the power supply circuit to the sensor apparatus and the one or more sensor apparatus to be different from one another.

12 . The communication system according to claim 1 , wherein
the sensor signal adopts a nibble signal defined under SAE-J2716 which is a standard set by Society of Automotive Engineers International.

13 . The communication system according to claim 12 , wherein
the nibble signal is assigned with a time stamp indicating time information, and the microcomputer determines a time stamp abnormality when the time stamp assigned to the nibble signal is different from a time stamp used in a calculation performed by the microcomputer.

14 . The communication system according to claim 13 , wherein
the microcomputer includes a calculation circuit, and, when the microcomputer determines the time stamp abnormality, the calculation circuit decreases a gain to be multiplied with the sensor signal when performing a sensor signal related calculation.

15 . The communication system according to claim 1 , wherein
the communication system is applied to an electric power steering apparatus equipped to a vehicle, the sensor apparatus detects an operation torque applied by a driver of the vehicle, and the microcomputer calculates, based on the operation torque detected by the sensor apparatus, a torque command indicating an assist torque required to be outputted by a motor.

Assignees

• Denso Corp

Inventors

• Suzuki Takashi
• Kabune Hideki
• Hayashi Katsuhiko
• Kozawa Takaharu

Classifications

• G05B15/02

  electric · CPC title

• B62D5/0412

  the axes of motor and steering column being parallel · CPC title

• B62D5/0463 Primary

  calculating assisting torque from the motor based on driver input · CPC title

• H04L25/4902

  Pulse width modulation; Pulse position modulation · CPC title

• H04L7/041 Primary

  using special codes as synchronising signal · CPC title