Failure detection method and apparatus for sensor network

• US 6,714,019 B2
• Filed: 01/24/2002
• Issued: 03/30/2004
• Est. Priority Date: 03/09/2001
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Otaka, Koji, Kiribayashi, Shinichi
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Benson, Walter
• Application Number:
  US10/053,586
• Publication Number:
  US 20020125890A1
• Time in Patent Office: 796 Days
• Field of Search: 324/525, 324/531, 324/512, 324/527, 324/537, 340/502, 340/506, 340/518, 702/62
• US Class Current: 324/525
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844

Abstract

A sensor network has a plurality of resistors connected to row lines and column lines in a matrix. A monitoring resistor is connected between ends of two adjacent row lines. One of the row lines is connected to a pull-up resistor and the other row line is grounded to form a series circuit. When a voltage is applied to the series circuit, a voltage across the monitoring resistor is inputted to an ECU. If the circuit is in the shorted condition, the voltage across the monitoring resistor is 0. If the circuit is in the open condition, the voltage is equal to the voltage applied to the circuit. If no failure is present in the series circuit, the voltage is equal to the divided voltage. Failure detection in column lines is performed in the same manner as the row lines.

Claims

1. A failure detection method for a matrix sensor network comprising:

connecting a plurality of pressure sensitive sensors to row lines and column lines in a matrix, each sensor changing a resistance thereof according to a pressure applied thereto, characterized by;

connecting a monitoring device to at least one of ends of two row lines and ends of two column lines to form a series circuit;

applying a voltage to the series circuit;

checking a voltage of the series circuit to detect failure of the matrix sensor network;

connecting one end of the series circuit to a pull-up resistor and grounding the other end;

applying the voltage to the series circuit through the pull-up resistor; and

checking the voltage across the monitoring device.

2. A failure detection method for a matrix sensor network comprising:

connecting a plurality of pressure sensitive sensors to row lines and column lines in a matrix, each sensor changing a resistance thereof according to a pressure applied thereto, characterized by;

connecting a monitoring device to at least one of ends of two row lines and ends of two column lines to form a series circuit;

applying a voltage to the series circuit;

checking a voltage of the series circuit to detect failure of the matrix sensor network; and

applying a same voltage to all row lines and column lines other than the two row lines and the two column lines of the series circuit.

3. A failure detection method for a matrix sensor network comprising:

connecting a plurality of pressure sensitive sensors to row lines and column lines in a matrix, each sensor changing a resistance thereof according to a pressure applied thereto, characterized by;

connecting a monitoring device to at least one of ends of two row lines and ends of two column lines to form a series circuit;

applying a voltage to the series circuit; and

checking a voltage of the series circuit to detect failure of the matrix sensor network;

wherein the monitoring device is one of a resistor and a diode.

4. A failure detection method for a matrix sensor network comprising:

connecting a plurality of pressure sensitive sensors to row lines and column lines in a matrix, each sensor changing a resistance thereof according to a pressure applied thereto, characterized by;

connecting a monitoring device to at least one of ends of two row lines and ends of two column lines to form a series circuit;

applying a voltage to the series circuit; and

checking a voltage of the series circuit to detect failure of the matrix sensor network; and

selecting in sequence at least one of two row lines and two column lines to change the series circuit to which the voltage is applied for failure detection.

5. A failure detection apparatus comprising:

a matrix sensor network having row lines and column lines, and a plurality of pressure sensitive sensors connected to the row lines and the column lines in a matrix, each sensor changing electric characteristics thereof according to a pressure applied;

a monitoring device connected to ends of at least one of two row lines and two column lines to form a series circuit;

a voltage source connected to the series circuit to detect a failure based on variations in output of the monitoring device; and

a pull-up resistor connected to one end of the series circuit, wherein the other end of the series circuit is grounded.

6. A failure detection apparatus comprising:

a matrix sensor network having row lines and column lines, and a plurality of pressure sensitive sensors connected to the row lines and the column lines in a matrix, each sensor changing electric characteristics thereof according to a pressure applied;

a monitoring device connected to ends of at least one of two row lines and two column lines to form a series circuit;

a voltage source connected to the series circuit to detect a failure based on variations in output of the monitoring device; and

a buffer circuit for applying a same voltage to all row lines and column lines other than the two row lines and the two column lines of the series circuit.

7. A failure detection apparatus comprising:

a matrix sensor network having row lines and column lines, and a plurality of pressure sensitive sensors connected to the row lines and the column lines in a matrix, each sensor changing electric characteristics thereof according to a pressure applied;

a monitoring device connected to ends of at least one of two row lines and two column lines to form a series circuit; and

a voltage source connected to the series circuit to detect a failure based on variations in output of the monitoring device.

wherein the monitoring device is one of a resistor and a diode.

8. A failure detection apparatus comprising:

a matrix sensor network having row lines and column lines, and a plurality of pressure sensitive sensors connected to the row lines and the column lines in a matrix, each sensor changing electric characteristics thereof according to a pressure applied;

a monitoring device connected to ends of at least one of two row lines and two column lines to form a series circuit;

a voltage source connected to the series circuit to detect a failure based on variations in output of the monitoring device; and

multiplexers connected to the row lines and column lines for selecting in sequence at least one of two row lines and two column lines to change the series circuit to which the voltage source is connected for failure detection.