Inertial unit ¶
The Inertial unit is made of:
- a 3-axis gyrometers with an angular speed of ~500°/s,
- a 3-axis accelerometer with an acceleration of ~2g.
The Inertial unit is located in the torso with its own processor.
Position relative to the Torso frame.
Output data ¶
The output data enables an estimation of the torso speed and attitude (Yaw, Pitch, Roll).
Compute Torso Angle Algorithm ¶
An SoftBank Robotics algorithm computing the torso Angle from accelerometers and gyrometers is programming inside the inertial board.
This algorithm used the good proprieties of each sensor: accelerometer is the only absolute reference and give the good torso angle in static mode. When some motion is detected, the output angle is computed with gyrometers which have a good behavior in dynamic. However, integration of gyrometers creates a bias of the compute angle, so in dynamic mode, a fusion of compute angle from accelerometer and gyrometer is done to reduce this bias.