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sbgisen / vesc

VESC Interface for ROS
Apache License 2.0
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What is RPM definition in VESC firmware? #20

Closed ssr-yuki closed 3 years ago

ssr-yuki commented 3 years ago

RPM calculated by VESC board (not a driver on PC) does not match with [rpm] unit, experimentally. We have to check algorithms on the firmware. Generally, to calculate RPM, the number of poles and sensor structures are required, and gear ratio is also needed if we want to know output velocity.

This issue is related to #18 .

ssr-yuki commented 3 years ago

Referring to the original VESC firmware, I understand that VESC returns velocity status not in RPM unit but in ERPM unit.

ERPM (electrical RPM) is defined by the following relationship:

Velocity Status [ERPM] = Mechanical Motor Velocity [RPM] * the Number of Motor Pole Pairs [-]
(the Number of Motor Poles = 2 * the Number of Motor Pole Pairs)

As pointed out in #18 , unit conversion with the number of motor pole pairs is required.