Method for determining the absolute angular position of the steering wheel of a motor vehicle, and optoelecronic steering angle sensor

A method of determining the angular position of the steering wheel of a motor vehicle, the method comprising:

• providing a light source;
• providing diametrically opposed first and second line sensors each having a plurality of image points positioned along a line at equal intervals with respect to one another, the line sensors each operable for generating light signals a function of the position and intensity of light traces imaged onto the image points of the line sensors;
• disposing the second line sensor with its longitudinal axis aligned with the longitudinal axis of the first line sensor;
• disposing a code transmitter between the light source and the line sensors, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensors, the code transmitter having a scanning line and a reference line for respectively imaging a scanning light trace and a reference light trace from the light source onto the image points of the line sensors, wherein the distance between the scanning line and the reference line is different at each angular position of the steering wheel such that the number of image points between the scanning light trace and the reference light trace imaged onto the line sensors is different at each angular position of the steering wheel, wherein the scanning light trace and the reference light trace each have a respective bright-dark light transition region imaged onto at least two image points of the line sensors, wherein the intensity of the bright-dark transition region varies over the at least two image points;
• averaging respective scanning and reference light signals generated from the first and second line sensors as a function of the intensity and the position of the light traces imaged onto the image points of the line sensors;
• and
• processing the averaged scanning light signal and the averaged reference light signal to determine the angular position of the steering wheel as a function of the distance between the respective bright-dark light transition regions of the averaged scanning light trace and the averaged light trace imaged onto the line sensor.

A method of determining the angular position of the steering wheel of a motor vehicle, the method comprising:

• providing a light source;
• providing a line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the line sensor operable for generating light signals as a function of the position and intensity of light traces imaged onto the image points of the line sensor;
• disposing a code transmitter between the light source and the line sensor, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensor, the code transmitter having a scanning line and a reference line for respectively imaging a scanning light trace and a reference light trace from the light source onto the image points of the line sensor, wherein the distance between the scanning line and the reference line is different at each angular position of the steering wheel such that the number of image points between the scanning light trace and the reference light trace imaged onto the line sensor is different at each angular position of the steering wheel, wherein the scanning light trace and the reference light trace each have a respective bright-dark light transition region imaged onto at least two image points of the line sensor, wherein the intensity of the bright-dark transition region varies over the at least two image points;
• processing a scanning light signal and a reference light signal generated by the line sensor in response to the scanning light trace and the reference light trace imaged onto the line sensor to compare the scanning light signal and the reference light signal with a predetermined reference pulse for determining correlation coefficients;
• and
• determining the angular position of the steering wheel as a function of the distance between extremes of the determined correlation coefficients.

A method of determining the angular position of the steering wheel of a motor vehicle, the method comprising:

• providing a light source;
• providing a line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the line sensor operable for generating light signals as a function of the position and intensity of light traces imaged onto the image points of the line sensor;
• disposing a code transmitter between the light source and the line sensor, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensor, the code transmitter having a scanning line and a reference line for respectively imaging a scanning light trace and a reference light trace from the light source onto the image points of the line sensor, wherein the distance between the scanning line and the reference line is different at each angular position of the steering wheel such that the number of image points between the scanning light trace and the reference light trace imaged onto the line sensor is different at each angular position of the steering wheel, wherein the scanning light trace and the reference light trace each have a respective bright-dark light transition region imaged onto at least two image points of the line sensor, wherein the intensity of the bright-dark transition region varies over the at least two image points;
• processing a scanning light signal and a reference light signal generated by the line senor in response to the scanning light trace and the reference light trace imaged onto the line sensor to determine focal points of the respective bright-dark transition regions of the scanning light signal and the reference light signal imaged onto the line sensor as a function of the position and intensity of the light traces imaged onto the line sensor;
• and
• determining the angular position of the steering wheel as a function of the number of image points between the focal points of the respective bright-dark light transition regions of the scanning light trace and the reference light trace imaged onto the line sensor.

An optoelectronic steering angle sensor for determining the angular position of a steering wheel of a motor vehicle, the sensor comprising:

• a light source;
• a line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the line sensor operable for generating light signals as a function of light traces imaged onto the image points of the line sensor;
• a code transmitter disposed between the light source and the line sensor, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensor, the code transmitter having a scanning line and a reference line for respectively imaging a scanning light trace and a reference light trace from the light source onto the image points of the line sensor, wherein the distance between the scanning line and the reference line is different at each angular position of the steering wheel such that the number of image points between the scanning light trace and the reference light trace imaged onto the line sensor is different at each angular position of the steering wheel, wherein the scanning light trace and the reference light trace each have a respective bright-dark light transition region imaged onto at least two image points of the line sensor;
• and
• an evaluating unit operable with the line sensor for processing a scanning light signal and a reference light signal generated by the line sensor in response to the scanning light trace and the reference light trace imaged onto the line sensor, the evaluating unit further operable for interpolating the scanning light signal and the reference light signal to produce a scanning light trace continuous signal and a reference light trace continuous signal, for comparing the respective scanning and reference light trace continuous signals with a predetermined threshold value for producing a scanning light trace transition signal having an edge and reference light trace transition signal having an edge, and for determining the angular position of the steering wheel as a function of the distance between the respective edges of the scanning light trace and the reference light trace imaged onto the line sensor.

An optoelectronic steering angle sensor for determining the angular position of a steering wheel of a motor vehicle, the sensor comprising:

• a light source;
• a first line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the first line sensor operable for generating light signals as a function of light traces imaged onto the image points of the first line sensor;
• a second line sensor diametrically opposed to the first line sensor, the second line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the second line sensor operable for generating light signals as a function of light traces imaged onto the image points of the second line sensor, wherein the second line sensor is disposed with its longitudinal axis aligned with the longitudinal axis of the first line sensor;
• a code transmitter disposed between the light source and the line sensors, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensors, the code transmitter having scanning and reference lines for respectively imaging scanning and reference light traces from the light source onto the image points of the line sensors, wherein the distance between the scanning and reference lines is different at each angular position of the steering wheel such that the number of image points between the scanning and reference light traces imaged onto the line sensors is different at each angular position of the steering wheel, wherein the scanning and reference light traces each have a respective bright-dark light transition region imaged onto at least two image points of the line sensors;
• and
• an evaluating unit operable with the line sensors for averaging respective scanning and reference light signals generated from the line sensors as a function of the intensity and position of the light traces imaged onto the image points of the line sensors, wherein the evaluating unit is further operable for processing the averaged scanning and reference light signals to determine the angular position of the steering wheel as a function of the distance between the respective bright-dark light transition regions of the averaged scanning and reference light traces.

An optoelectronic steering angle sensor for determining the angular position of a steering wheel of a motor vehicle, the sensor comprising:

• a light source;
• a line sensor having a plurality of image points positioned along a line at equal intervals with respect to one another, the line sensor operable for generating light signals as a function of light traces imaged onto the image points of the line sensor;
• a code transmitter disposed between the light source and the line sensor, the code transmitter concentrically surrounding a steering spindle of a steering wheel of a motor vehicle and fixed to the steering spindle to rotate therewith with respect to at least one of the light source and the line sensor, the code transmitter having a scanning line and a reference line for respectively imaging a scanning light trace and a reference light trace from the light source onto the image points of the line sensor, wherein the distance between the scanning line and the reference line is different at each angular position of the steering wheel such that the number of image points between the scanning light trace and the reference light trace imaged onto the line sensor is different at each angular position of the steering wheel, wherein the scanning light trace and the reference light trace each have a respective bright-dark light transition region imaged onto at least two image points of the line sensor;
• and
• an evaluating unit operable with the line sensor for processing a scanning light signal and a reference light signal generated by the line sensor in response to the scanning light trace and the reference light trace imaged onto the line sensor to determine focal points of the respective bright-dark light transition regions of the scanning light signal and the reference light signal imaged onto the line sensor as a function of the position and intensity of the light traces imaged onto the line sensor, wherein the evaluating unit is further operable for determining the angular position of the steering wheel as a function of the distance between the focal points of the respective bright-dark light transition regions of the scanning light trace and the reference light trace.