Sonars

See also

NAO H25 | NAO H21 | NAO T14 | NAO T2

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Specifications

Sonar: 2 emitters, 2 receivers.

NAO is equipped with two ultrasonic sensors (or sonars) which allow it to estimate the distance to obstacles in its environment.

NAO V5	Frequency: 40kHz Resolution: 1cm-4cm (depending on distance) Detection range: 0.20 m - 0.80 m Under 20 cm there is no distance information, the robot only knows that an object is present. Above 80 cm the value returned is an estimation. For further details, read the important tips in US/Sensor (m). Effective cone: 60°
NAO V4 and V3.x	Frequency: 40kHz Resolution: 1cm Detection range: 0.25m - 2.55m Effective cone: 60° The detection range goes from 25 cm to 255 cm, but under 25 cm there is no distance information, the robot only knows that an object is present.

Location

Position relative to the Torso frame.

Sonar name	X(m)	Y(m)	Z(m)	WX(rd)[deg]*	WY(rd)[deg]*	WZ(rd)[deg]*
US sensor 1	0.0537	-0.0341	0.0698	0.0	-0.1745 [-10.0]	-0.3490 [-20.0]
US sensor 2	0.0477	-0.0416	0.0509	0.0	0.2618 [15.0]	-0.4363 [-25.0]

To access values by using ALMemory key names, see: Sonar Actuator and Sensors.

Note

We adopt the roll, pitch and yaw notation for angle representation. So, to construct an homogeneous transform with rotation (Wx,Wy,Wz) use T=rotZ(Wz)*rotY(Wy)*rotX(Wx)

• US sensor 3 is symmetrical to US sensor 1 with respect to sagittal plane of the robot.
• US sensor 4 is symmetrical to US sensor 2 with respect to sagittal plane of the robot.