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The final phase of the project includes designing the rotation mechanism to move the entire assembly which includes: the lifting mechanism, the grasping mechanism, and the payload which have been designed in the previous phases of the project.
Explicit Design Constraints
Explicit Design Constraints
Rotary table must be gear-driven by the third servo, and the servo must travel through at least 150° of rotation during the pickup/drop-off sequence
Each team will receive a 10” diameter circle of 0.75” thick MDF and two drop zone boards (also 0.75” thick MDF)
The circle has a 1/8” diameter hole in the center, added during the manufacturing process, that your rotary table can pivot; it can be modified as needed such as drilling additional holes to anchor gears, servos, etc.
MDF circles and drop-off boards are designed to be arranged in a polygon pattern
Each mechanism must rotate 180*(N-2)/N degrees, where N is the number of groups in the class.
Implicit Design Constraints
Implicit Design Constraints
The servo can not exceed 180 degrees of rotation
Previous phase deliverables must integrate with this phase
Design Considerations
Design Considerations
The team calculated that the mechanism must rotate 135 degrees based on the 8 groups in the class. The servo used in this section had constraints that only allowed the servo to rotate between 150 and 180 degrees. With this wide range, there were an infinite amount of gear ratios that could have been chosen. The team decided on an 11:9 ratio with a 165 degree servo rotation. The team then decided on a 55 tooth drive gear and a 45 tooth gear rotating the arm. A diametric pitch of 20 was chosen because it is a standard diametral pitches, and it also allows for both of the gears to fit on the 10 inch platform comfortably.
Gear Calculations
Gear Calculations
Rotation Mechanism in Action
Position 1 - Pickup
Position 1 - Pickup
Position 2 - Drop Off
Position 2 - Drop Off
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