| 摘要 |
PROBLEM TO BE SOLVED: To obtain an angular velocity by which an angular velocity can be sensed with high accuracy by a method wherein a plurality of external-magnetic-field sensing elements which are at right angles to each other are driven, their signals are detected and the angular velocity of every axis of rotation is computed on the basis of the signals. SOLUTION: External-magnetic-field sensing elements 111 are arranged in parallel around the X-axis to the Z-axis so as to detect three-dimensional rotations. An addition drive circuit 125 at a drive detection circuit 12a outputs a driving signal to the external- magnetic-field sensing elements 111 so as to be driven when an oscillating signal, at an oscillation circuit 123, which is added is input. External-magnetic-field signals at the X-axis to the Z-axis which are detected 111 are detected 121, and its detection voltage Vo is input to an A/D conversion part at a microprocessor 126. Then, the detection voltage Vo is compared with a reference voltage Vref , a voltage Vd for external-magnetic-field cancellation is output from a D/A conversion part so as to be increased or decreased unit Vo =Vref , and an internal magnetic field is given. An angle change and an angular velocity per unit time in the X-axis to the Z-axis are computed and output 12b on the basis of the voltage Vd for external-magnetic-field cancellation. Consequently, the angular velocity is not sensed on the basis of a change in an impedance, but it can be sensed with high accuracy. |
