Joints

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Sign convention

Given a joint that links two body parts of the robot, the body part that is closer to the trunk is considered to be fixed and the body part that is farther from the trunk is the one that rotates around the joint axis.

To perform the rotation of the body parts, we place a frame at each joint. When the robot is at the zero pose, all joint frames have the same orientation. Then, roll rotations take place around the X axis, pitch rotations around the Y axis and yaw rotations around the Z axis.

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/rollPitchYaw.png

Head joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_headjoint_3.3.png

Motion range

Joint name Motion Range (degrees) Range (radians)
HeadYaw Head joint twist (Z) -119.5 to 119.5 -2.0857 to 2.0857
HeadPitch Head joint front and back (Y) -38.5 to 29.5 -0.6720 to 0.5149
Click the joint name to see all related ALMemory key names .

Anti collision limitation

Due to potential shell collision at the head level, the Pitch motion range is limited according to the Yaw value.

HeadYaw HeadPitch Min HeadPitch Max HeadYaw HeadPitch Min HeadPitch Max
(degrees) (radians)
-119.52 -25.73 18.91 -2.086017 -0.449073 0.330041
-87.49 -18.91 11.46 -1.526988 -0.330041 0.200015
-62.45 -24.64 17.19 -1.089958 -0.430049 0.300022
-51.74 -27.50 18.91 -0.903033 -0.479965 0.330041
-43.32 -31.40 21.20 -0.756077 -0.548033 0.370010
-27.85 -38.50 24.18 -0.486074 -0.671951 0.422021
0.0 -38.50 29.51 0.000000 -0.671951 0.515047
27.85 -38.50 24.18 0.486074 -0.671951 0.422021
43.32 -31.40 21.20 0.756077 -0.548033 0.370010
51.74 -27.50 18.91 0.903033 -0.479965 0.330041
62.45 -24.64 17.19 1.089958 -0.430049 0.300022
87.49 -18.91 11.46 1.526988 -0.330041 0.200015
119.52 -25.73 18.91 2.086017 -0.449073 0.330041

Left Arm joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_larmjoint_3.3.png
Joint name Motion Range (degrees) Range (radians)
LShoulderPitch Left shoulder joint front and back (Y) -119.5 to 119.5 -2.0857 to 2.0857
LShoulderRoll Left shoulder joint right and left (Z) -18 to 76 -0.3142 to 1.3265
LElbowYaw Left shoulder joint twist (X) -119.5 to 119.5 -2.0857 to 2.0857
LElbowRoll Left elbow joint (Z) -88.5 to -2 -1.5446 to -0.0349
LWristYaw Left wrist joint (X) -104.5 to 104.5 -1.8238 to 1.8238
LHand Left hand Open and Close Open and Close
Click the joint name to see all related ALMemory key names .

Right Arm joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_rarmjoint_3.3.png
Joint name Motion Range (degrees) Range (radians)
RShoulderPitch Right shoulder joint front and back (Y) -119.5 to 119.5 -2.0857 to 2.0857
RShoulderRoll Right shoulder joint right and left (Z) -76 to 18 -1.3265 to 0.3142
RElbowYaw Right shoulder joint twist (X) -119.5 to 119.5 -2.0857 to 2.0857
RElbowRoll Right elbow joint (Z) 2 to 88.5 0.0349 to 1.5446
RWristYaw Right wrist joint (X) -104.5 to 104.5 -1.8238 to 1.8238
RHand Right hand Open and Close Open and Close
Click the joint name to see all related ALMemory key names .

Pelvis joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_pelvisjoint.png
Joint name Motion Range (degrees) Range (radians)
LHipYawPitch Left hip joint twist (Y-Z 45°) -65.62 to 42.44 -1.145303 to 0.740810
RHipYawPitch* Right hip joint twist (Y-Z 45°) -65.62 to 42.44 -1.145303 to 0.740810
Click the joint name to see all related ALMemory key names .

Note

LHipYawPitch and RHipYawPitch are physically just one motor so they cannot be controlled independently. In case of conflicting orders, LHipYawPitch always takes the priority.

Left Leg joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_llegjoint.png

Motion range

Joint name Motion Range (degrees) Range (radians)
LHipRoll Left hip joint right and left (X) -21.74 to 45.29 -0.379472 to 0.790477
LHipPitch Left hip joint front and back (Y) -88.00 to 27.73 -1.535889 to 0.484090
LKneePitch Left knee joint (Y) -5.29 to 121.04 -0.092346 to 2.112528
LAnklePitch Left ankle joint front and back (Y) -68.15 to 52.86 -1.189516 to 0.922747
LAnkleRoll Left ankle joint right and left (X) -22.79 to 44.06 -0.397880 to 0.769001
Click the joint name to see all related ALMemory key names .

Anti collision limitation

Due to potential shell collision at the ankle level, the Roll motion range is limited according to the Pitch value.

LAnklePitch LAnkleRoll Min LAnkleRoll Max LAnklePitch LAnkleRoll Min LAnkleRoll Max
(degrees) (radians)
-68.15 -2.86 4.30 -1.189442 -0.049916 0.075049
-48.13 -10.31 9.74 -0.840027 -0.179943 0.169995
-40.11 -22.80 12.61 -0.700051 -0.397935 0.220086
-25.78 -22.80 44.06 -0.449946 -0.397935 0.768992
5.73 -22.80 44.06 0.100007 -0.397935 0.768992
20.05 -22.80 31.54 0.349938 -0.397935 0.550477
52.87 0.00 2.86 0.922755 -0.000000 0.049916

Right Leg joints

https://developers.softbankrobotics.com/sites/default/files/repository/51_html_nao/_images/hardware_rlegjoint.png

Motion range

Joint name Motion Range (degrees) Range (radians)
RHipRoll Right hip joint right and left (X) -45.29 to 21.74 -0.790477 to 0.379472
RHipPitch Right hip joint front and back (Y) -88.00 to 27.73 -1.535889 to 0.484090
RKneePitch Right knee joint (Y) -5.90 to 121.47 -0.103083 to 2.120198
RAnklePitch Right ankle joint front and back (Y) -67.97 to 53.40 -1.186448 to 0.932056
RAnkleRoll Right ankle joint right and left (X) -44.06 to 22.80 -0.768992 to 0.397935
Click the joint name to see all related ALMemory key names .

Anti collision limitation

Due to potential shell collision at the ankle level, the Roll motion range is limited according to the Pitch value.

RAnklePitch RAnkleRoll Min RAnkleRoll Max RAnklePitch RAnkleRoll Min RAnkleRoll Max
(degrees) (radians)
-68.15 -4.30 2.86 -1.189442 -0.075049 0.049916
-48.13 -9.74 10.31 -0.840027 -0.169995 0.179943
-40.11 -12.61 22.80 -0.700051 -0.220086 0.397935
-25.78 -44.06 22.80 -0.449946 -0.768992 0.397935
5.73 -44.06 22.80 0.100007 -0.768992 0.397935
20.05 -31.54 22.80 0.349938 -0.550477 0.397935
52.87 -2.86 0.00 0.922755 -0.049916 0.000000