12.1 Project Proposal
Introduction
Our adjustable IPad stand offers users the ability to personalize their IPad experience more comfortably. Modern IPads have the option to tilt the screen, but would have to be stacked on a pile of books to change elevation, whereas our mechanism would allow the user to raise the IPad to the preferred eye level and also tilt it as an entire body, reducing back and neck strain. Although current IPad stands exist, they are manually operated, requiring more time and work for the user to achieve their desired position. Our device aims to use linkages and motors to provide a smooth, easy, and reliable experience for a variety of IPad weights.
Problem Statement
A constant complaint in the workplace is comfort. We often find ourselves leaning over our screens, straining our eyes, back, and neck to work and read what is on our IPads. Although attempts have been made to better adjust the IPad’s positioning, current IPad stands use friction hinges or joints to approximate the positioning, whereas our mechanism aims to be more precise with the user's desired positioning. We would use a motorized lift mechanism to provide continuous motion that changes both height and tilt angle. Some of the key challenges we will face are achieving synchronous motion, supporting the weight of the IPad, and creating a mechanism that can provide two types of motion - translation and rotation.
Proposed Mechanism
Our IPad stand will contain a dual motorized lift linkage that connects to the platform at the corners to lift and lower. From the side, there will be arms exposed that are connected by pivots to allow for vertical extension. The motors will be attached to the base to ensure stability. To control the system, there will be buttons on the mechanism that allow the platform to go upwards, downwards, and tilt per the user’s input. The plate will act like a plane with parallel linkages to lift and rotate about the base. Our design aims to ensure stability, coordination, and rigidity throughout the entire body. With a standard IPad weighing 3-5 pounds, we aim for our mechanism to support 5 pounds.
Proposed Scope of Work
First, we will work on CAD models to design a lift prototype that is cohesive and can withstand the forces and torque needed to adjust the positioning of the IPad. Then we will analyze our design by calculating the degrees of freedom and analyzing velocity/force/position profiles. Before fabrication, the linkage mechanisms will need to be tried and true on paper, as well as finding optimal dimensions for all parts. As well, proper materials will be researched and analyzed to see what can withstand the movement and force of the IPad during usage. An early prototype will be created, where we can stop any problems that arise. After we have addressed all issues, the final mechanism will be fabricated and tested. To take this project further, we could improve our current range of motion of the tabletop bivector (what the IPad rests on) from one direction to two. This means the plane that the IPad rests on could tilt in any direction, and two different directions at once. Achieving this could be done by making each corner independent of itself and on a separate lift.
Preliminary Design Ideas
The battery-powered mechanism will include 2 lifts, each one being a four-bar mechanism - one on either side. There will be two buttons - one that raises the entire platform and the other that lowers it. Using actuators to convert the power, the lifts will have 1 degree of freedom. The IPad will be resting on a stable surface consisting of raised edges to prevent it from falling. These raised edges will aid in the tilting aspect of the stand itself, which will be accomplished through motor control as well, consisting of another 2 buttons to adjust based on user preference.
Grashoff
All links in the lifts are equivalent. This ensures that each four-bar linkage satisfies S+L=P+Q.
Gruebler equation
The mechanism will have two buttons to control the movement of upward and downward motion. Based on the analysis of the linkages and joints, this mechanism will allow for 1 DOF which is consistent with the expected motion of the system.
M = 3(L-1) - 2(J_1) - J_2
L = 6 [ground, lift frame (x2), platform]
J_1 = 6
J_2 = 2
Therefore M = 1 DOF