Elevator Upgrades

A project to evaluate the usefulness of a Geneva Drive gearsystem (in a high-speed capacity) by upgrading CJ's elevator with a geneva drive.

Basic Specifications
The elevator is powered by a single window motor. The window motor direct-drives a spool which is 11.4 cm in diameter. A fabric strap is wrapped around the spool to lift the elevator.

The elevator has a stroke of approximatley 48 in.

Unmodified Robot
Two videos of the rebuilt elevator were analyzed using Tracker. Data from the first trial showed that the elevator is raised at a rate of $$ 0.285 \pm 0.023 $$ m/s. The results from the second trial were consistent with the first: $$ 0.295 \pm 0.030 $$ m/s.

Post-Upgrade
Performance data will also be collected after upgrades are complete.

Performance Goals
The upgraded mechanism must lift the man ====== ipulator mass up the full height in a set amount of time which is

competitive at the highest level.

Declare the following variables:
 * $$ h $$: The height of the lift
 * $$ t_g $$: The time performance goal
 * $$ m $$: The mass of the manipulator being lifted

Then, the average velocity of the lift is: $$ v_{avg} = h / t_g $$

In order to achieve the maximum possible performance and account for deceleration of the lift, the maximum

speed is $$ 2 h/t_g $$ and will be achieved in $$t_g/2$$ seconds.

Thus, the required acceleration is $$ a = \frac{4 h}{t_g^2} $$, and the required force is $$ F_A = m (a+g) $$

Design Variables
The performance goals leave several free design variables:
 * Pulley diameter
 * Geneva specs (pins, slots, separation distance, pin distance)
 * Gearbox ratio
 * Motor

Supplies

 * Motor (small BaneBots?)
 * Gearbox (P60?)
 * Flat stock (for making the geneva gears)
 * Bearing(s)?