Best homing tactics for quadruped robot?

Hi ! I am using AK70-10 motors. The motors looses its zero position whenever its turned off. Are there any good tactics to set the zero configuration for the motor, without lifting the robot and placing the limps perpendicular to the base ?


our robots also loose the joint zero position when powered down.
That’s because we don’t have angular sensors on the joint outputs.

We have an encoder disk with index pulse on the motors that is used to simplify startup and to make the joint position initialization more repeatable.

We use calibration bars on the legs to once determine the offset between the encoder index pulse and the joint zero - those offsets are then stored in the software.

At startup we now only have to align the joints roughly.
The robot moves the legs, finds the next index pulse and applies the known offset.

Note that because of the 9:1 gear reduction the motor driver cards detect 9 index pulses per joint revolution.
That means that the operator has to orient the legs within ± 20 degrees of the zero position to find the correct index pulse.

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