Suction cups are way better than multi-finger grippers.
Multi-finger grippers rely on "affordances" i.e. space between the boxes to get the fingers in. If the boxes are pushed up against one another, you've got to do something to make space for the fingers first. So to grab a box with a multi-finger gripper you need space at the top, left and right.
Suction cups, on the other hand? They only need access to the top. No need for space at the left and right, no need to slide things to make space, just apply the suction cup and pull upwards.
Suction cups can also be made of soft, flexible rubber so if the planning is a bit inaccurate? No problem, the suction cup just bends. A multi-finger gripper, though? If the fingers are rigid and strong enough to lift a 30kg bag then they're also probably rigid and strong enough to punch a hole in an adjacent bag.
Suction cups do have a bunch of disadvantages, of course. Porous materials you can't get a seal on. Vacuuming up detritus and messing up your vacuum generator. The payload swinging about on the flexible suction cup. Losing vacuum and dropping the load if there's a power cut.
But they're certainly a great starting point in an application like this one.
Multi-finger grippers rely on "affordances" i.e. space between the boxes to get the fingers in. If the boxes are pushed up against one another, you've got to do something to make space for the fingers first. So to grab a box with a multi-finger gripper you need space at the top, left and right.
Suction cups, on the other hand? They only need access to the top. No need for space at the left and right, no need to slide things to make space, just apply the suction cup and pull upwards.
Suction cups can also be made of soft, flexible rubber so if the planning is a bit inaccurate? No problem, the suction cup just bends. A multi-finger gripper, though? If the fingers are rigid and strong enough to lift a 30kg bag then they're also probably rigid and strong enough to punch a hole in an adjacent bag.
Suction cups do have a bunch of disadvantages, of course. Porous materials you can't get a seal on. Vacuuming up detritus and messing up your vacuum generator. The payload swinging about on the flexible suction cup. Losing vacuum and dropping the load if there's a power cut.
But they're certainly a great starting point in an application like this one.