1. Nodding LIDAR For Applied Research Associates By Roscoe Kane and John Barton

2. Background  LIDAR stands for Light Detection And Ranging  Emits a pulsed laser beam and measures the time between emission and return to determine distance  Most systems are at best 2 dimensional, with 1 axis of sweep that returns 1 dimension of range

4. Problem Statement  Develop a system to adapt a 2 dimensional LIDAR system into a 3 dimensional LIDAR system by adding a second axis of rotation

5. Specs  30º minimum sweep angle .5hz minimum scan rate  Capable of any orientation  Capable of being disabled  Safety for both humans and robot

6. Our Solution  Move the entire system about it’s center of gravity  Use a resonant spring oscillator to generate an even frequency and allow for a smaller motor  Use a Maxon motor and motor controller to start, stop and maintain oscillation

7. Spring Sizing  In order to size a spring for our resonant spring oscillator we will need to find the moment of inertia of the unit and bracket  We solved this equation for K, or spring constant: K=(2fnπ)^2I

8. Spring Sizing   We used the equation I=KMR^2 to estimate the moment of inertia of the bracket and LIDAR unit combined   K is a constant which represents the shape of the object which we estimated to be approximately.5   M is the mass of the object   R is the radius of rotation   I is moment of inertia, the same as in the previous equation

9. Challenges Faced   The numbers we have calculated are generally not the specified values for springs to order   We had to calculate the size of wire, number of windings and other values in order to come up with an accurate description of the spring we needed   We have yet to find someone who sells springs that meet our requirements

10. Communications   We have 2 options for communicating between our Maxon motor controller and the PC that ultimately receives and interprets the data 1. 1. We could connect the PC directly to the motor controller and use C code to send and receive data 2. 2. We could connect to 2 microcontrollers, 1 that has controls the oscillation and another that deals with the encoder feedback

11. Encoding Angular Data  In order for the computer to make use of the data it must know the exact angle at which the measurement was taken  Our Maxon motor has an encoder and the motor driver has the ability to interpret and send back the encoder data to our microcontroller or computer

12. Budget ItemPriceQuantityCostStatus motor with encoder$2001 need spring$46.641$47 need motor controller$51 on hand HCS08$21 on hand.5" Aluminum Plate$451 ft^2$45in shop.25" Aluminum Plate$251 ft^2$25in shop DB9 cable$202$40 need 3/4" Aluminum Rod$163/4"$16in shop bearings$332$67 need 8/32X3/4" Slotted Machine Screws$4.101$4 need total $450 total cost to us $357

13. Workload Distribution

14. Solid Modeling