Clarify what "gear_retio" represents
ssr-yuki opened this issue · comments
In vesc_hardware_interface, there exist a parameter named gear_ratio. It means a kind of reduction ratio, however, the value is calculated not by (input displacement) / (output displacement) but by (hall sensor value) / (input displacement).
We have to introduce a new variable representing hall sensor values per round to clear the complexity. Joint effort and joint velocity is wrong because of the complexity of gear_ratio variable.
Hall sensor-based pulse satisfies the following equation:
the Number of Pulses on 1 Rotation [pulse/round] = the Number of Motor Poles [/round] * the Number of Hall Sensors [pulse]
I conclude that gear_ratio should represent velocity ratio: it depends only on reduction gears.
Both the number of motor poles and the number of hall sensors have to be parameterized for vesc_hw_interface. The former is also required to calculate accurate joint velocity (see #20 for more details).