Object detection device, object detection method, and control device

A control device controlling operations of each of a plurality of ultrasonic sensors, the plurality of ultrasonic sensors being included in an object detection device, the plurality of ultrasonic sensors being configured to each transmit a search ultrasonic wave and receive a reflected wave resulting from reflection of the search ultrasonic wave by an object, to thereby detect the object, the search ultrasonic waves transmitted from the respective ultrasonic sensors having mutually different characteristics that are mutually distinguishable,

• wherein the control device comprises:
• a transmission timing setting unit configured to set a transmission timing of transmitting the search ultrasonic wave for each of the ultrasonic sensors, and
• a transmission instruction unit configured to instruct each of the ultrasonic sensors to start to transmit the search ultrasonic wave, based on the transmission timing set by the transmission timing setting unit;
• and
• the transmission timing setting unit is configured to:
• defining one of the plurality of ultrasonic sensors as a first ultrasonic sensor and another one of the plurality of ultrasonic sensors as a second ultrasonic sensor, set a delay time between a first transmission timing which is the transmission timing of the first ultrasonic sensor and a second transmission timing which is the transmission timing of the second ultrasonic sensor;
• and
• set the delay time to be equal to or greater than a value obtained by dividing a maximum value of a transmission path length difference within an overlap region by the speed of sound, the transmission path length difference being a difference between a length of a transmission path of the search ultrasonic wave from the first ultrasonic sensor and a length of a transmission path of the search ultrasonic wave from the second ultrasonic sensor, the overlap region being a range in which a first detection region and a second detection region overlap one another, the first detection region being a detection region of the first ultrasonic sensor, the second detection region being a detection region of the second ultrasonic sensor.

An object detection method that is executed by an object detection device,

• the object detection device comprising:
• a plurality of ultrasonic sensors configured to each transmit a search ultrasonic wave and receive a reflected wave resulting from reflection of the search ultrasonic wave by an object, to thereby detect the object, and
• a control unit configured to control operations of the respective ultrasonic sensors;
• wherein the object detection method comprises:
• a transmitting step in which the respective ultrasonic sensors transmit the search ultrasonic waves which have mutually different characteristics that are mutually distinguishable,
• a transmission timing setting step in which a transmission timing of transmitting the search ultrasonic wave are set for each of the ultrasonic sensors, and
• an instructing step in which each of the ultrasonic sensors is instructed to start to transmit the search ultrasonic wave, based on the set transmission timing;
• and
• wherein the transmission timing setting step comprises:
• defining one of the plurality of ultrasonic sensors as a first ultrasonic sensor and another one of the plurality of ultrasonic sensors as a second ultrasonic sensor, setting a delay time between a first transmission timing which is the transmission timing of the first ultrasonic sensor and a second transmission timing which is the transmission timing of the second ultrasonic sensor;
• and
• setting the delay time to be equal to or greater than a value obtained by dividing a maximum value of a transmission path length difference within an overlap region by the speed of sound, the transmission path length difference being a difference between a length of a transmission path of the search ultrasonic wave from the first ultrasonic sensor and a length of a transmission path of the search ultrasonic wave from the second ultrasonic sensor, the overlap region being a range in which a first detection region and a second detection region overlap one another, the first detection region being a detection region of the first ultrasonic sensor, the second detection region being a detection region of the second ultrasonic sensor.