Trim disabled vs trim with 0 values

BlackSoldierB

When i disable the trim function the robot drives almost straight (+- 0,5 cm).
But when i enable it the robot starts to curve to the right (around 5 cm), at the end it correct so it is pointing forward again. This even happens when all the trim values are 0.
This results are on a hard surface and over a distance of 90 cm.

Anyone have seen this effect before?

Publison

You will have to be more specific. Which robot? Which code? Did you do a calibration on the servos?

BlackSoldierB

Yes i did calibrate the servo's.Below is the code of both situations.
I would expect that both situations produced the same result.
I tested both versions 4-5 times, and the results where consistent.

This is the code with the trim enabled, this will move to the right.

drive_trim(1);
drive_trimSet(AB_FORWARD, AB_LEFT, 0);
drive_trimSet(AB_FORWARD, AB_RIGHT, 0);
drive_trimSet(AB_BACKWARD, AB_LEFT, 0);
drive_trimSet(AB_BACKWARD, AB_RIGHT, 0);
 
drive_speed(0,0); 
drive_setRampStep(4);
drive_setMaxSpeed(32);

double ticks = 900 / 3.25; //900 mm
drive_goto(-ticks, -ticks);

This is the code with trim disabled, this will do +- 0,5 cm.

drive_trim(0);
drive_trimSet(AB_FORWARD, AB_LEFT, 0);
drive_trimSet(AB_FORWARD, AB_RIGHT, 0);
drive_trimSet(AB_BACKWARD, AB_LEFT, 0);
drive_trimSet(AB_BACKWARD, AB_RIGHT, 0);
 
drive_speed(0,0); 
drive_setRampStep(4);
drive_setMaxSpeed(32);

double ticks = 900 / 3.25; //900 mm
drive_goto(-ticks, -ticks);