Robotic Recycler

Robot Arm Module:

The arm mechanism is a six bar linkage with four binary links and two ternary links. The goal of the mechanism is to move the claw from the extended position to the contracted position so that the bottle is delivered in the correct orientation for pick up and for launch. The mechanism can cross over into an unwanted geometry, however this is prevented by using hard stops attached to the claw attachment link. The mechanism is to be driven by an electric motor in two directions and as such requires some slightly more sophisticated motion control. Ideally, the mechanism would be improved by reconfiguration to employ the Grashoff condition such that a full rotation of the input link provides the desired motion and also returns the linkage to the initial position.

Synthesis of the Arm Module motion:

The arm mechanism was originally conceptualized as a four-bar linkage. When the preliminary designs of the launcher module were delivered, it was clear that it would be advantageous to add an element of controlling the orientation of the item to be "recycled," and a simple four bar does not deliver nearly complex enough motion to achieve this. Hence I began work on modifying a four-bar linkage, knowing that the topology must include four binary links and two ternary links for a one degree of freedom motion (among several other configurations as outlined in Norton's Design of Machinery, see Norton Table 2-2). The mechanism was contrived mainly by graphical synthesis using a home-made compass, which allowed simultaneous dimensional synthesis. Several heuristics were discovered in the process regarding the geometry of motion and they will be discussed below.