Abstract: A system for directly measuring tire grip conditions is provided which can measure a skidding condition with no need of applying a vibration. A tire rotation speed sensor comprising a detection gear and a magnet sensor is mounted to a rotating shaft of a tire. An output of the tire rotation speed sensor is analyzed in time-frequency domain to detect vibrations caused by slips, thereby determining tire grip conditions, such as a slip ratio and a slip angle. By detecting fluctuations in rotation based on the cause-effect relation between the occurrence of tire slips and the occurrence of fluctuations in rotation, the tire slips can be directly detected. Therefore, the tire grip conditions can be confirmed with high accuracy.

Abstract: A magnetic motion sensor has: two magnetic sensors aligned in a direction along which changes in a magnetic field shift for detecting an appearance of the changes; a differential means for taking out a differential signal of output signals from these two magnetic sensors; and a timing detection means for generating a pulse, indicating a timing at which the changes in a magnetic field pass through either of the magnetic sensors, when an output signal of the magnetic sensor in question strides over a threshold value, while generating a pulse, indicating a timing at which the changes in a magnetic field pass through in between the magnetic sensors, when the differential signal strides over the threshold value.

Abstract: A system for directly measuring tire grip conditions is provided which can measure a skidding condition with no need of applying a vibration. A tire rotation speed sensor comprising a detection gear and a magnet sensor is mounted to a rotating shaft of a tire. An output of the tire rotation speed sensor is analyzed in time-frequency domain to detect vibrations caused by slips, thereby determining tire grip conditions, such as a slip ratio and a slip angle. By detecting fluctuations in rotation based on the cause-effect relation between the occurrence of tire slips and the occurrence of fluctuations in rotation, the tire slips can be directly detected. Therefore, the tire grip conditions can be confirmed with high accuracy.

Abstract: A magnetic motion sensor has: two magnetic sensors aligned in a direction along which changes in a magnetic field shift for detecting an appearance of the changes; a differential means for taking out a differential signal of output signals from these two magnetic sensors; and a timing detection means for generating a pulse, indicating a timing at which the changes in a magnetic field pass through either of the magnetic sensors, when an output signal of the magnetic sensor in question strides over a threshold value, while generating a pulse, indicating a timing at which the changes in a magnetic field pass through in between the magnetic sensors, when the differential signal strides over the threshold value.