US 6,782,969 B2Granted

Vehicle steering control system

AssigneesToyoda Koki Kabushiki Kaisha, Toyota Jidosha Kabushiki Kaisha

InventorsKazumasa Kodama, Masahiro Miyata

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Abstract

A vehicle steering control system is provided which is capable of reliably protecting a motor for driving a wheel steering shaft. The offset output characteristic of a current sensor for detecting the electric current applied to the steering shaft drive motor is actually measured prior to the actual use of the steering control system, and offset compensation information is prepared based on the measured value of the offset output characteristic for storage in an EEPROM. Further, an output value of the current sensor and an output value of a reference current measuring system are measured independently of each other with the supply voltage for use in measurement being set to a constant value. Then, current gain compensation information is prepared based on the output values so measured and is stored in the EEPROM. In the later actual use (i.e., after shipment) of the control system, the output of the current sensor is compensated based on the offset compensation information and the current gain compensation information.

Claims7

Dependent claims

A vehicle steering control system for a vehicle wherein a steering angle to be given to a wheel steering shaft is determined in dependence on a steering angle given to a handle shaft for steering operation and a driving state of a vehicle so that said wheel steering shaft is rotationally driven by a steering shaft drive motor to be given said determined steering angle, said control system comprising:

a current sensor including a current detection resistance provided on a motor power supply path from a vehicle-mounted battery to a driver for said steering shaft drive motor for detecting a current applied to said steering shaft drive motor and a differential amplifier circuit for outputting a voltage across said current detection resistance as a current detection signal;
offset compensation information storage means for storing an offset compensation information used in offset-compensating an output of said current sensor, said offset compensation information being prepared based on a measuring value which is obtained, in advance of an actual use of said system, by measuring an offset output generated by said differential amplifier circuit when said voltage across said current detection resistance is zero;
and
offset compensation means for compensating the output of said current sensor based on said offset compensation information in the actual use of said system.

1 more element

Dependencies are inferred from the claim text.