My team is considering adding a constant force spring to our very heavy three-stage elevator to make it faster, and wondering if it matters where it is added. Is it more effective pulling up the second stage from the first stage or from the top of the second stage down to the carriage?
Thanks
Is it continuous or cascade?
We have our constant force spring on the first stage pulling the second “up” with good success. You can see it in our reveal video. Team 6886.
It is continuous.
I would highly suggest using constant force spring(s). First off, your motors and driver will thank you. By using the constant force spring, the power from the elevator motor goes only to moving the elevator (not also counteracting gravity). With this, the elevator can maintain its position without powering the motor enabling better control of the elevator mech and preventing you from dumping current into the motor and, very possibly, frying them.
As for a continuous elevator, I believe you’ll need a constant force spring for each stage of the elevator. You can see in their reveal video that 1619 has a similar setup to yours except they only have 2 stages. If you look closely at their elevator, you can see there’s one spring to hold the carriage up relative to the inner stage and another spring to hold the inner stage up relative to the outer stage.
On a personal example, you can see the difference in the movement of our team (1661’s) elevator (ignoring the lack of driver practice in the first clip). In the first clip, although it’s subtle, you can see the elevator is very jittery. Because of that our intake flops up and down quite a lot. After we added the constant force spring to our elevator the motion of the elevator is significantly smoother. The bigger takeaway from using the constant force spring is more the motor current draw. In software, you could emulate the constant force spring, to a good extent, you’d just see a much higher current draw from the motors and would most likely be stalling the motors to maintain the elevator’s position (not too good for 775pros).