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ezWheelSAS / swd_ros_controllers

ROS nodes to control motors powered by the ez-Wheel Safety Wheel Drive (SWD®) technology.
https://www.ez-wheel.com/
GNU Lesser General Public License v2.1
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to have steady low speed is difficult #54

Closed JacquesRoubaud closed 2 years ago

JacquesRoubaud commented 2 years ago

Hi I am setting the speed to low values, like 0.01m/s up to 0.04m/s I can see that the movement is not fully linear . At 0.01m/s one of the motor stops (or accelerate?) randomly for a very short period time, so short it's hard to see if it stops or accelerates. Overall, I can see that at very low speed the direction fluctuates with speed = 0.08m/s, everything is ok Did you notice that and do you have some suggestion ?

GMezWheel commented 2 years ago

Hi @JacquesRoubaud, At this time, the swd motor velocity range is [40-2000] rpm by default. Thus, a target velocity value in the range [1-40] is forced to 40rpm by the diff_drive_controller node. You can set the min value of the VelocityModeParameters.vl_velocity_min_amount during commissioning.

JacquesRoubaud commented 2 years ago

Hi ! Good news ! is there anything particular to think about when setting the lowest velocity value ? can I set 1 rpm ? Can you indicate me where to find the file with the parameter VelocityModeParameters.vl_velocity_min_amount ? thanks

ez-Support commented 2 years ago

It is not suitable to set-up the velocity speed under 40 rpm. The motor will not be able to follow the a target velocity below this value.