I'm Back
I've been swamped with projects and other school stuff this quarter. The quarter is finally coming to an end and I'm getting a little more free time on my hands.
So time for update number eins. My term project for my mechatronics class.
We had to make a 2 DOF plotter and the DOF's had to be other coordinates besides x,y. My group choose to make a polar plotter. It turned out alright. It certainly could have been much better. We should have spent a little more time on the mechanical part, we're ME's for gosh sakes. But I'm pretty sure we spent more time on the software. I think that that paid off in the end because in my opinion we had the best code and second best hardware.
Any way it is controlled by the ME405 board which runs an Atmega128 and has two pretty legit motor driver chips on board. The professor that usually teaches the class wrote a mock RTOS that we use in our program. We have a couple tasks which are run by the scheduler at time intervals that we set up.
The way that the plotter works is that we send it a file of commands and it executes them. Our teacher wanted it to be similar to G Code. So we have commands like pen up,pen down, go to Point defined by x,y, draw a line and we implemented go to a point defined by r,theta. We are running a PID controller to position the arm and the slider. Oh and all the calculations like x,y to r,theta and the PID calc's are all done using integer math. No floats/doubles were used at. So we wrote a nice little arc tangent function that uses Simpson's Rule to approximate the angle. Numerical integration using Simpson's Rule was much quicker and more accurate than a Taylor Series Expansion.
Here's video of it drawing a vertical line. Ours was probably the best vertical line drawer in the class.
Ill hopefully start posting a lot more in the next week since its spring break and I'll be back home and have access to the mill and lathe!!!
So time for update number eins. My term project for my mechatronics class.
Any way it is controlled by the ME405 board which runs an Atmega128 and has two pretty legit motor driver chips on board. The professor that usually teaches the class wrote a mock RTOS that we use in our program. We have a couple tasks which are run by the scheduler at time intervals that we set up.
The way that the plotter works is that we send it a file of commands and it executes them. Our teacher wanted it to be similar to G Code. So we have commands like pen up,pen down, go to Point defined by x,y, draw a line and we implemented go to a point defined by r,theta. We are running a PID controller to position the arm and the slider. Oh and all the calculations like x,y to r,theta and the PID calc's are all done using integer math. No floats/doubles were used at. So we wrote a nice little arc tangent function that uses Simpson's Rule to approximate the angle. Numerical integration using Simpson's Rule was much quicker and more accurate than a Taylor Series Expansion.
Here's video of it drawing a vertical line. Ours was probably the best vertical line drawer in the class.
Ill hopefully start posting a lot more in the next week since its spring break and I'll be back home and have access to the mill and lathe!!!
