Sonars


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.

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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.