2D Physics: How to have a character "grab" onto wall with hand

So a ragdoll character is flying through the air. Now, when a player holds down a certain key while the ragdoll's hand is in contact with an object, the hand should latch to the object at that point. I've got this all set up rather well, other than that all of the 2D joints seem to be to weak or glitchy. The ragdoll will either flail about crazily or the joint will act as a rope that allows the ragdoll to float off away from the joint before pulling back slowly.

So two legs, two arms, a head, and a jetpack all have hinge joints connecting them to the main body. Then, i also have a "sensor" object with a spring joint connecting it to the right arm at the hand. This sensor is what is supposed to connect to the object. I have probably overcomplicated this at this point. If you're interested in helping and need more information, I will provide it.