Obstacle detection device

An obstacle detection device comprising:

• one or more first distance sensors each for transmitting a transmission wave toward an obstacle;
• one or more second distance sensors each for detecting a reflected wave from said obstacle;
• a transmission control unit for controlling one of said first distance sensors to cause this first distance sensor to continuously transmit a transmission wave;
• a reception control unit for allowing one of said second distance sensors to detect a reflected wave from the obstacle;
• a time measurement unit for stopping the continuous transmission of the transmission wave transmitted by said first distance sensor at a time at which said reflected wave is detected, and for detecting said obstacle and measuring a third time which has elapsed from a time at which said time measurement unit stops the continuous transmission of the transmission wave to a time at which said reflected wave disappears in said one of said second distance sensors which has detected said reflected wave;
• and
• an obstacle determination unit for causing one of said first distance sensors to transmit a transmission wave during a fixed time period after said time measurement unit measures said third time, and for measuring a first time which has elapsed from a time at which said transmission starts to a time that a reflected wave is detected, and a second time which has elapsed from a time at which said transmission is stopped to a time at which the reflected wave disappears to determine that an obstacle exists when a time difference between said third time and said first time or between said first time and said second time is equal to or shorter than a predetermined allowed time.