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This phase is dedicated to designing the grasping mechanism that will be used to pick up the payload previously designed.
Design Constraints
Design Constraints
Have at least one fourbar linkage
Operated by one 180 degree MG-996R Servo that can't be directly attached to a link
Mechanism must mount to test rig
Payload must be picked up anywhere along midline
Shouldn't include gears
Overall want a simple design
Mary's Design
Mary's Design
Pros: Simple to build and design
Cons: Don't know if it will work with the servo motor
Ginger's Design
Ginger's Design
Pros: Easy to design and good gripping technique
Cons: Hard to be supported by one Servo motor
Noah's Design
Noah's Design
Pros: Only one side of the mechanism moves, simple design
Cons: May not be able to fashion to grip the payload correctly
Design Direction
The team decided to use the third design as the basis of their grasping mechanism. This was because it was overall a simple yet effective design. The design included a four bar linkage, will work with one Servo motor, and didn't include any gears.
Graphical Linkage Synthesis
Graphical Linkage Synthesis
Design Considerations
The design created, as mentioned previously, was based on the the third design created in the brainstorming session. However, there were a few major design changes implemented when creating the GLS. The most major of these changes was the change in the placement of the crank link, moving it to the underside of the servo made the design more space conserving, especially when considering an interference with the test rig. An extra piece was added to the top of the design to make an easy attachment point to the test rig, while also removing any concerns of the arm being in the way of the grasping mechanism. Overall, the design came together as an amalgamation of the previous ideas, while implementing pieces of information that were gained while creating the GLS.
Modified Gruebler's Equation:
Degrees of Freedom Analysis
DOF = 3 ( 4 - 1) - 2 (4 + 0) - 0
DOF = 1
∴ The structure is a mechanism.
Grasping Mechanism in Action
Open View
Open View
Closed View
Closed View
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