Patent ID: 8588029
Filing Date: 2013-11-19
Classification: G01S

Abstract:
1. An obstacle detection device mountable on a surface of a movable body, comprising: a transmitting portion including one or more transmitting elements and outputting an ultrasonic wave from the one or more transmitting elements as a transmitting wave; a receiving portion including a plurality of receiving elements disposed in an array and receiving a reflected wave at the plurality of receiving elements, the reflected wave being the transmitting wave reflected by an obstacle; a distance calculating portion calculating a distance to the obstacle based on a time difference between a transmitting time when the transmitting portion outputs the transmitting wave and a receiving time when the receiving portion receives the reflected wave and a speed of the transmitting wave; a direction calculating portion calculating a direction of the obstacle based on a phase difference between a phase of the reflected wave received with one of the plurality of receiving elements and a phase of the reflected wave received with another of the plurality of receiving elements, a distance between the one of the plurality of receiving elements and the another of the plurality of receiving elements, and a wavelength of the transmitting wave; a distance storing portion storing the distance to the obstacle calculated by the distance calculating portion; a direction storing portion storing the direction of the obstacle calculated by the direction calculating portion; a distance change calculating portion calculating the amount of distance change based on the distance to the obstacle stored in the distance storing portion, the amount of distance change being generated due to a change in relative position of the obstacle to the surface of the movable body; a direction change calculating portion calculating the amount of direction change based on the direction of the obstacle stored in the direction storing portion, the amount of direction change being generated due to the change in relative position of the obstacle to the surface of the movable body; a determining portion determining a shape of the obstacle and the relative position of the obstacle to the movable body based on the direction of the obstacle calculated by the direction calculating portion, the amount of distance change calculated by the distance change calculating portion, and the amount of direction change calculated by the direction change calculating portion, the determining portion outputting a determination result; and a shortest distance calculating portion, wherein (1) when the determining portion determines that the obstacle is a planar object, the shortest distance calculating portion calculates a shortest distance “D (2) when the determining portion determines that the obstacle is a non-planar object, the shortest distance calculating portion calculates the shortest distance “D where “D” is the distance to the obstacle calculated by the distance calculating portion, “θ” is the direction of the obstacle calculated by the direction calculating portion, and “d” is a distance between a shortest distance calculating point of the surface of the movable body and a position at which the obstacle detection device is disposed, and the shortest distance calculating portion outputs a calculation result.