Method and device for calculating velocity

A velocity calculating device to be mounted on a movable body having at least a front wheel and a rear wheel and for moving on a traveling surface, comprising:

• processing circuitry;
• an acceleration sensor operatively coupled to the processing circuitry and configured to sense an acceleration of an axle of one of the front and rear wheels in vertical directions of the movable body;
• and
• an angular velocity sensor operatively coupled to the processing circuitry and configured to sense a pitch angular velocity of the movable body, wherein
• the processing circuitry is configured:
• to acquire the acceleration of the axle of one of the front and rear wheels in the vertical directions of the movable body;
• to acquire the pitch angular velocity of the movable body;
• to detect a time difference between the acceleration in the vertical directions and the pitch angular velocity;
• and
• to calculate a moving velocity of the movable body based on a ratio of a wheelbase with respect to the time difference, the wheelbase being a distance between the axle of the front wheel and the axle of the rear wheel,
• wherein the processing circuitry includes a high-pass filter and a low-pass filter configured to remove components of the acceleration in the vertical directions and the pitch angular velocity with frequencies outside a range from 1 Hz to 2 Hz;
• and
• wherein the acceleration sensor and the angular velocity sensor are incorporated within the velocity calculating device.