2021
CENTER OF GRAVITY MEASUREMENT DEVICE JOSEPH CORNWALL, KEEGAN STANPHILL , CAMERON EGGART, MARK JASZKOWIAK,, PIYUSH BASNET
BACKGROUND
DESIGN ITERATIONS
PEGBOARD DESIGN
Schweitzer Engineering Laboratories designs and manufactures a wide range of electronic products. The center of gravity (CG) is needed by SEL in order to conduct failure analysis on their devices. For complex electrical parts it can be difficult to determine the CG.
OBJECTIVE
The objective of this project is to create a device capable of calculating the CG of SEL products. Previous Team
Snapshot 1 Design
Use of a pegboard design allows for the mounting of custom fixtures and the testing of a variety of different sized objects. A numbered grid on the table surface allows for the locating and input of custom origins for testing.
User Interface Rotary encoder for switching between device functions.
SEL Products
Tare: Record load cell values while loaded under the weight of the device and fixtures.
REQUIREMENTS Calculates 3D center of gravity for any object Automatic operation Accuracy within 1% or 0.1 inches of actual value Can hold a static load of 50 lbf Operate 1-year maintenance free Operate using standard 120V AC outlet $5000 budget
Final Design
Load cells (green) support the bottom plate. Clevis rod ends and ball joint rod ends form the hinge which allows the upper plate to tilt. A 150 lbf linear actuator is used for tilting table.
Select An Origin: Allows the user to set a custom XY origin.
Take CG Measurements: Records load values,
actuates, and records angled load cell values. The CG is displayed on the LCD screen.
DEVELOPMENT OF MATH MODEL The device uses three different load cells which act as the feet of the device. Force measurements are taken first while the table is level in order to calculate the X and Y coordinates. The table is then lifted by the actuator to a known angle where new force measurements are taken to calculate how the center of gravity shifts forward in order to find the Z coordinate. Special Thanks to: Dr. Michael Maughan Jonathan Richards Sally Mei
Max Johnson Alex Olson