Processing unit for generating control signal, controller with the processing unit for controlling actuator, and program executed in the processing unit

• US 20070255931A1
• Filed: 04/05/2007
• Published: 11/01/2007
• Est. Priority Date: 04/27/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Takayama, Eiji, Kobayashi, Hidetoshi
• Granted Patent: US 7,826,935 B2
• Time in Patent Office: Days
• US Class Current: 712/222
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/26 using computer, e.g. microprocessor
• CPC Class Codes: G05B 19/0428 Safety, monitoring G05B19/0423 takes precedence

Abstract

A controller with a processing unit and a floating-point processor is disposed in a vehicle to control an actuator according to detected parameters sent from sensors. The processor generates a floating-point control parameter indicating a first quantity of control from the detected parameters at floating-point calculations, and the unit generates a fixed-point control parameter indicating a second quantity of control from the detected parameters at fixed-point calculations. The unit converts the floating-point control parameter into a converted control parameter of fixed-point representation and judges from both the converted control parameter and the fixed-point control parameter whether a failure has occurred in the processor. When no failure has occurred in the processor, the unit generates a control signal from the floating-point control parameter. The actuator is operated according to the control signal so as to give the first quantity of control to a controlled object.

Claims

1. A processing unit comprising:

a parameter receiving section which receives a floating-point control parameter generated in a floating-point processor from a detected parameter on the basis of a floating-point calculation, the floating-point control parameter indicating a first quantity of control for a controlled object;

a parameter generating section which receives the detected parameter and generates a fixed-point control parameter indicating a second quantity of control for the controlled object from the detected parameter on the basis of a fixed-point calculation;

a converting section which converts the floating-point control parameter of floating-point representation into a converted control parameter of fixed-point representation;

a failure judging section which judges from both the converted control parameter and the fixed-point control parameter whether or not a failure has occurred in the floating-point processor;

a signal generating section which generates a control signal from the floating-point control parameter when the failure judging section judges that no failure has occurred in the floating-point processor; and

a signal outputting section which outputs the control signal to an actuator such that the actuator is operated according to the control signal so as to give the first quantity of control to the controlled object.

2. The processing unit according to claim 1, wherein the failure judging section is adapted to judge that a failure has occurred in the floating-point processor when a difference between the converted control parameter and the fixed-point control parameter is larger than a predetermined value.

3. The processing unit according to claim 2, wherein the judgment of the failure judging section is based on an absolute value of the difference.

4. The processing unit according to claim 1, wherein the converting section is adapted to perform the conversion by using least significant bit data of the floating-point control parameter and offset data, the least significant bit data expresses a physical value corresponding to a lowest bit of the converted control parameter, and the offset data indicates a position of a base point in the converted control parameter.

5. The processing unit according to claim 1, wherein the failure judging section has a conversion possibility checking block which judges whether or not the floating-point control parameter of floating-point representation can be expressed by fixed-point data of a predetermined fixed-point representation, and a converting block which performs the conversion when the conversion possibility checking block judges that the floating-point control parameter of floating-point representation can be expressed by fixed-point data.

6. The processing unit according to claim 1, wherein the floating-point control parameter is obtained as a result of a predetermined floating-point calculation among a plurality of floating-point calculations possible to be performed in the floating-point processor.

7. The processing unit according to claim 1, wherein the signal generating section is adapted to generate a fail-safe control signal indicating a fail-safe quantity of control for the controlled object when the failure judging section judges that a failure has occurred in the floating-point processor, and the signal outputting section is adapted to output the fail-safe control signal to the actuator such that the actuator is operated according to the fail-safe control signal so as to give the fail-safe quantity of control to the controlled object.

8. A controller comprising a processing unit and a floating-point processor,

wherein the floating-point processor is adapted to receive a detected parameter and generate a floating-point control parameter indicating a first quantity of control for a controlled object from the detected parameter on the basis of a floating-point calculation, and

the processing unit comprises:

a parameter receiving section which receives the floating-point control parameter from the floating-point processor;

a parameter generating section which receives the detected parameter and generates a fixed-point control parameter indicating a second quantity of control for the controlled object from the detected parameter on the basis of a fixed-point calculation;

a converting section which converts the floating-point control parameter of floating-point representation into a converted control parameter of fixed-point representation;

a failure judging section which judges from both the converted control parameter and the fixed-point control parameter whether or not a failure has occurred in the floating-point processor;

a signal generating section which generates a control signal from the floating-point control parameter when the failure judging section judges that no failure has occurred in the floating-point processor; and

a signal outputting section which outputs the control signal to an actuator such that the actuator is operated according to the control signal so as to give the first quantity of control to the controlled object.

9. The controller according to claim 8, wherein the floating-point processor is adapted to be possible to perform a plurality of floating-point calculations and to generate the floating-point control parameter as a result of a predetermined floating-point calculation among the floating-point calculations.

10. A computer program, which is loaded into a processing unit and is executed to control a controlled object, the program comprising:

a control parameter receiving segment which receives a floating-point control parameter generated from a detected parameter in a floating-point processor on the basis of a floating-point calculation, the floating-point control parameter indicating a first quantity of control for the controlled object;

a control parameter generating segment which generates a fixed-point control parameter indicating a second quantity of control for the controlled object from the detected parameter on the basis of a fixed-point calculation;

a converting segment which converts the floating-point control parameter of floating-point representation into a converted control parameter of fixed-point representation;

a judging segment which judges from both the converted control parameter and the fixed-point control parameter whether or not a failure has occurred in the floating-point processor;

a control signal generating segment which generates a control signal from the floating-point control parameter when it is judged that no failure has occurred in the floating-point processor; and

an outputting segment which outputs the control signal to an actuator such that the actuator is operated according to the control signal so as to give the first quantity of control to the controlled object.