For my robot, I have a claw that is attached to a six bar to pick up caps. I have a gear ratio that has the motor attached to the small gear, and the small gear is attached to the big gear, meaning that the lift is geared for torque. I tested out the motor with the programming and the motor is clearly moving the gears, and the lift is clearly going up, but it’s not able to go up all the way. Is it the gear ratio that needs to be changed? Or is it something else?
Can it be moved to maximum extension by hand? Easily? If not, then it’s not the motors’ fault. If it can be moved easily by hand, do you have any rubber bands or elastics to help carry the arm’s weight? If not, you should add some so the motor doesn’t have to carry the whole weight of the arm.
Would you mind taking a picture? You could try to force the lift up to see if it’s a motor or structure problem. If it goes up, your motor / gearing is too weak, and if it does not it’s being prevented by structure. Make sure the internal gear set of the motor is set to torque. If it’s a torque motor and not being prevented by structure, just too weak, I would look into putting more bands
How many motors do you have on it, and are they 393’s or V5?
I would suggest checking for friction points.
Check if all motors are going in the same direction. Add rubber bands or another motor.
Speaking of friction are you using screws or axels as joints?
If you are using axels everywhere I would recommend switching to screws in places where you can. I actually find screws easier to use. Here is a video showing the different types of screw joints. I prefer the last type shown, but I don’t use a three hole spacer instead I just put a washer then a nylock on.
Whats the gear ratio?
also try reducing weight on the 6 bar. use aluminium, and make sure your claw doesn’t weigh too much
+1 A heavy claw was the downfall of one of my sister team’s designs. They had a really cool lift plan, but didn’t account for claw weight.
we had a sister team use a turntable for their claw… and had a lift weighing twice that of their drive… and it was geared for speed on 2 393’s.
Lol that happened to us too. We didnt have any caps to practice with and our lift could barely lift itself with a cap
I usually overestimate the torque needed in order to lift anything. It’s not the best practice, but at least I’m not stuck rebuilding to increase torque. Most of the time, I guess pretty well.
I have been reading “sister team” as “my siblings team” for a long time and I was thinking it is odd that so many people have a sister on a different team than them. I now realize that this means another team in your organization, or a team you collaborate with.
Checking points of friction like somebody else mentioned (you ideally should be able to rotate each spacer freely for a quick test)
tension the lift (sometimes between between more than one bar linkages)
-account for the weight of the intake
-check the strain’s the motors have to deal with (which include checking for shaft deformity [in simpler terms bent axles] ) and what does the motor actually have to “drive”
All these things are possibilities: however my best guess would be tension (if it is weak or even non-existent) as that is generally the case if lifts are unable to overcome a point where they can not go over that is nearing the top as people generally tension only the bottom bars while doing really nothing with the rest