Omnidirectional rotational speed and rotational direction sensor

A system, comprising:

• a magnetic field sensor, including:
• a chip having at least a first, a second, and a third magnetic field measuring element, which are configured to output a first, second, and third magnetic field signal respectively, amplitudes of which are proportional to a magnetic field emanating from a rotating object, wherein directions of normal vectors of the first, the second, and the third magnetic field measuring elements are linearly independent of each other, wherein the first measuring element is a lateral Hall sensor, and the second and the third measuring elements are vertical Hall sensors, and wherein the normal vectors of the first, the second, and the third magnetic field measuring elements are at an angle of 90° relative to one another;
• a signal acquisition unit to determine a first differential signal and a second differential signal, wherein the first differential signal is based on a difference between the first magnetic field signal of the first magnetic field measuring element and the second magnetic field sensor of the second magnetic field measuring element, and wherein the second differential signal is based on a difference between the first magnetic field signal of the first magnetic field measuring element and the third magnetic field signal of the third magnetic field measuring element, and wherein the signal acquisition unit is further configured to determine a combined signal from the first magnetic field signal of the first magnetic field measuring element and the first differential signal and second differential signal, wherein the chip is arranged in a plane which is parallel to a tangential plane of the rotating object;
• and
• an evaluation unit to generate an output signal, which contains a speed of motion and a direction of motion of the rotating object;
• and
• a pole wheel with teeth and gaps, the pole wheel being magnetically coded, wherein the pole wheel is the rotating object.

A method for determining a rotational speed and a rotational direction of a rotating object using a magnetic field sensor, the method comprising:

• a) detecting a first, a second, and a third magnetic field signal from a first magnetic field measuring element, a second magnetic field measuring element, and a third magnetic field measuring element respectively;
• b) determining a first differential signal from a difference between the first magnetic field signal of the first magnetic field measuring element and the second magnetic field signal of the second magnetic field measuring element;
• c) determining a second differential signal from a difference between the first magnetic field signal of the first magnetic field measuring element and the third magnet field signal of the third magnetic field measuring element;
• d) calculating a combined signal from the first magnetic field signal of the first magnetic field measuring element and the first differential signal and second differential signal;
• e) calculating and outputting an output signal, which contains a speed of motion and a direction of motion of the rotating object;
• wherein the magnetic field sensor includes:
• a chip having at least the first, the second, and the third magnetic field measuring element, which are configured to output the first, the second and the third magnetic field signal respectively, amplitudes of the first, the second, and the third magnetic field signals are proportional to a magnetic field emanating from a rotating object, wherein directions of normal vectors of the first, the second, and the third magnetic field measuring elements are linearly independent of each other, wherein the first measuring element is a lateral Hall sensor, and the second and the third measuring elements are vertical Hall sensors, and wherein the normal vectors of the first, the second, and the third magnetic field measuring elements are at an angle of 90° relative to one another, wherein the chip is arranged in a plane which is parallel to a tangential plane of the rotating object;
• a signal acquisition unit to determine the first differential signal and the second differential signal, and wherein the signal acquisition unit is further configured to determine the combined signal;
• and
• an evaluation unit to generate the output signal, which contains the speed of motion and the direction of motion of the rotating object.

A method for determining a rotational speed and a rotational direction of a rotating object using a magnetic field sensor, the method comprising:

• a) detecting, using a first, second, and third magnetic field measuring element of the magnetic field sensor, a first, a second, and a third magnetic field signal, respectively, from a magnetic field emanating from the rotating object, wherein amplitudes of the first, the second, and the third magnetic field signals are proportional to a magnetic field emanating from a rotating object, wherein directions of normal vectors of the first, second, and third magnetic field measuring elements are linearly independent of each other, wherein the first measuring element is a lateral Hall sensor, and the second and the third measuring elements are vertical Hall sensors, and wherein the normal vectors of the first, the second, and the third magnetic field measuring elements are at an angle of 90° relative to one another;
• b) determining a first differential signal from a difference between the first magnetic field signal of the first magnetic field measuring element and the second magnetic field of the second magnetic field measuring element;
• c) determining a second differential signal from a difference between the first magnetic field signal of the first magnetic field measuring element and the third magnetic field signal of the third magnetic field measuring element;
• d) calculating a combined signal from the magnetic field signal of the first magnetic field measuring element and the first differential signal and second differential signal;
• and
• e) calculating and outputting an output signal, which contains a speed of motion and a direction of motion of the rotating object;
• wherein the first, the second, and the third field measuring elements are situated on a common chip, and form the magnetic field sensor, and wherein the chip is arranged in a plane which is parallel to a tangential plane of the rotating object.