Jack Gillies & Jeremiah GillFor AUTOTECH 2AC3Instructor: Lucian Balan

SOLIDWORKS DESIGN AND SIMULATION

PROJECT

March 19th, 2015

Constraints:

-Must be able to grip 3 prismatic shapes: -Must be controlled by given servo motor, 5 rotations to close/open-Must fit onto standard robot tool interface-All parts must be able to be manufactured-Assembly without interference-Must use standard fasteners -Robust and self-contained

Final Design

Final Design

Redesign

- After we finished the modeling, we realized the gripper isn’t big enough to fit the cube

- We measured the cube face to face and ignored the hypotenuse length of the cube

- Redesign took about 10 hours – Would have been easier if we modeled more parametrically.

Final Design

-522.19 grams

-137 parts, 32 Unique parts

-Can grip objects up to 80mm in width

- 84.3 mm maximum height from arm interface

- 194 mm maximum width (to back of servo)

Final Design

Assembly Animation

Inspiration

-Camera Shutter closes equally around central point-Will make contact without lateral slip with any part.-Operates by turning overlapping “leaves” towards inside-Leaves are turned by pins which are driven by a central turning ring

Initial Design

-5 Leaves overlapping (2mm thick) -Leaves Spaced by washers of same thickness-Assembly held in by retaining ring

Initial Design

-5 Pins of varying length (increments of 2mm) to turn the leaves -Pins are pushed through slots in turning ring-Portion of bevel gear drives turning ring

Issues

-Overlap of leaves may cause “tipping” or rocking of gripped piece

-We decided to mirror whole assembly so 2 apertures grip piece at different heights

Retaining Case

-Revolved profile of all turning parts to create casing to retain rotational motion

-Mounting features for Motor assembly-Identical mounting brackets for M6 bolts

-Upper holes machined for M4 screws to hold in upper leaf base.

-This part will probably have to be casted in aluminum.

Drive Train

-Total ratio needed is 39/1800 (turning ring degrees per motor degree)-Simple bevel gear and pinion would not be suitable-Additional gears achieve following ratio:

15𝑃1

41𝐺1

15𝑃2

41𝐺2

18𝐵𝑃1

120𝐵𝑃2≈ 39/1800

-Gearbox created to mount gears from motor to Retaining case

Drive Train

Turner Synchronization

-Lower turning plate is driven by bevel gear

-Upper turning plate is connected by turner synchros (shown in pink)

-Assembly is held together with set screws

-Plates slide inside grooves of retaining case

Spacer Cuff

-This part spaces the whole assembly out from the arm interface

-This allows the gripper to grip taller parts in closer to the center

Design Drawbacks

-Weight

-May shear objects

-Large width – cannot fit into small spaces

-Can only grip objects up to 80mm in diameter

-Many parts only serviceable if completely disassembled

-Leave assemblies are 54 mm apart – parts shorter than this will only be gripped by one leaf assembly.

Questions?