Double reverse four bar lifts keep the weight of a load centered over the base of the robot instead of lifting it up in front of the robot. This helps prevent the robot from tipping over. The double reverse four bar lift has a significant height advantage over a four bar lift without the lifting the load in front of the robot.
This is really a niche thing, but this paragraph could also include the fact that the center of mass of the lift itself shifts forward relative to its starting position. In other words, as the lift goes up, the robot becomes increasingly unstable despite the load moving completely vertical. This is because the midsection of the lift moves towards the load due to the geometry of the DR4B. To combat this, you can power the DR4B from the bottom 4 bar –– lightening the weight of the midsection.
I’m not sure if I’m just misreading this paragraph or if it’s mentioned elsewhere. I just think this distinction should be explicitly stated.
By the way, I think you guys did a fantastic job on this wiki post. It’s very clear and informative.
Can you add the existence of the DR8B to the list of weird varieties? We’ve prototyped one for the memes but didn’t get a good enough version to take a picture.
Thanks for the suggestion, but I believe we already have an example of this in the last section that talks about how the DR4B design isn’t completely restricted to 4-bars and can be a combination of different lifts.
