Hello,
I recently started with a Quadruped project. The robot is a SQ3U Symmetric Quadruped robot. I have already calibrated the motors to center(1500) and started to develop gaits for the robot. One problem is that one or two side of the robot is heavier than the rest. In center position, When I raise the leg(Femur) of one of the legs the robot actually tilts or falls down to that position but if I raise the other two femurs of the remaining legs, the robot is balanced. Any inputs or comments on this? Is there a way to make the robot stable?
Getting a 12DoF quad to walk is arguably harder than a 12 or 18DoF hexapod, because the center of weight must always be between the three supporting legs.
The first step, as you have done, is to mount the motors mechanically as closed to 1500 as possible. The second step is to adjust for any offsets via the software until each of the legs is at 90 degrees (perfectly).
This is because, despite the servo being “close” to 90 degrees at 1500, most servos are off by a little, and this fractional angle means the difference between walking or toppling over.
The only other way to correct for this is by changing the walking gait itself.
Last, it’s important the center of weight be as close to the center of the robot as possible - you should be able to adjust this with the battery.