Furuta Pendulum - Revision history

KrystianZimowski: /* Reflections */

2010-03-18T22:34:03Z

Reflections

KrystianZimowski: /* Reflections */

2010-03-18T22:33:49Z

Reflections

KrystianZimowski: /* Circuit */

2010-03-18T19:25:34Z

Circuit

KrystianZimowski: /* Circuit */

2010-03-18T16:59:57Z

Circuit

MatthewLuther: /* Code */

2010-03-18T00:57:51Z

Code

MatthewLuther: /* Code */

2010-03-18T00:56:37Z

Code

MatthewLuther: /* Mechanical Design */

2010-03-18T00:52:22Z

Mechanical Design

KrystianZimowski: /* Reflections */

2010-03-17T17:48:22Z

Reflections

KrystianZimowski: /* Results */

2010-03-17T17:16:38Z

Results

KrystianZimowski: /* Results */

2010-03-17T17:14:53Z

Results

@@ Line 337: / Line 337: @@
 == Reflections ==
 Overall, we had a successful execution of this project, because of the timeline we laid for ourselves. We broke down our project into many mechanical and electrical milestones so that we could test if parts of the pendulum were properly working before we put it all together and risk failure.
 '''Successes'''
 *Mechanical

@@ Line 336: / Line 336: @@
 == Reflections ==
+Overall, we had a successful execution of this project, because of the timeline we laid for ourselves. We broke down our project into many mechanical and electrical milestones so that we could test if parts of the pendulum were properly working before we put it all together and risk failure.
 '''Successes'''
-We broke down our project into many mechanical and electrical milestones so that we could test if parts of the pendulum were properly working before we put it all together and risk failure.
 *Mechanical
 **Milestone 1--The base of the pendulum was built and tested for stability, turning the motor on and off with various speeds. The base was mechanically robust.

@@ Line 61: / Line 61: @@
 ===Circuit===
-Our circuit was nearly identical to the circuit diagram from the Mechatronics Lab 4.  All that was added was an input to the PIC triggered by a push button attached to 3.3V. [[Image:motor circuit.png|center]] The motor-encoder circuit can also be downloaded [http://hades.mech.northwestern.edu/images/f/fd/Motor_Encoder_circuit.pdf here]
+Our circuit was nearly identical to the circuit diagram from the Mechatronics Lab 4.  All that was added was an input to the PIC triggered by a push button attached to 3.3V. [[Image:motor circuit.jpg|center]] The motor-encoder circuit can also be downloaded [http://hades.mech.northwestern.edu/images/f/fd/Motor_Encoder_circuit.pdf here]
 == Code ==

@@ Line 61: / Line 61: @@
 ===Circuit===
-Our circuit was nearly identical to the circuit diagram from the Mechatronics Lab 4.  All that was added was an input to the PIC triggered by a push button attached to 3.3V. [[Image:furuta circuit.png|center]] The motor-encoder circuit can also be downloaded [http://hades.mech.northwestern.edu/images/f/fd/Motor_Encoder_circuit.pdf here]
+Our circuit was nearly identical to the circuit diagram from the Mechatronics Lab 4.  All that was added was an input to the PIC triggered by a push button attached to 3.3V. [[Image:motor circuit.png|center]] The motor-encoder circuit can also be downloaded [http://hades.mech.northwestern.edu/images/f/fd/Motor_Encoder_circuit.pdf here]
 == Code ==

@@ Line 235: / Line 235: @@
 /** Other Functions:  From Lab 4 ********************************************/
+//  All of these functions are documented in the LAB 4 information section
 void initMotorPWM(void)
 {

@@ Line 173: / Line 173: @@
 	while(1) // run forever
 	{
-		//resets loop index for derivative portion of control equation
+		//resets loop index for derivative portion of control equation.  It resets when the length of the data array (num_data) is reached by the counter, iteration
 		if (iteration > num_data)
 			{iteration = 0;}

@@ Line 10: / Line 10: @@
 There are three sections of the pendulum that can each be addressed separately: the base assembly with motor housing (including the motor itself); the arm assembly, which includes the horizontal arm, the vertical arm, and the encoder apparatus; and the box into which the whole pendulum was placed, including mechanical stops, the PIC and electrical circuitry, and a button to start the program.  Each section begins with a parts list; generic terms like "block" or "slab" indicate that these parts were made from aluminum scraps and can be just as effective with a different size or shape, or that they can be easily machined to fit any design.
-Aluminum was used for most parts because it was readily available, easy to machine, light, and mechanically robust.  We wanted as light a design as possible because the motor we used was had no gearhead, so the torque was naturally going to be lower. We decided to use the motor with no gearhead to avoid any backlash since the pendulum requires rapid adjustments in motor position and direction to keep the vertical arm up.  However, we also wanted to minimize shaking from the pendulum operation, so the base had to be fairly heavy and sturdy.
+Aluminum was used for most parts because it was readily available, easy to machine, light, and mechanically robust.  We wanted as light a design as possible because the motor we used had no gearhead, so the torque was naturally going to be lower. We decided to use the motor with no gearhead to avoid any backlash since the pendulum requires rapid adjustments in motor position and direction to keep the vertical arm up.  However, we also wanted to minimize shaking from the pendulum operation, so the base had to be fairly heavy and sturdy.
 [[Image:base.png|thumb|150 px|Base sub-assembly to keep the motor upright and stabilize the pendulum|right]]

@@ Line 336: / Line 336: @@
 == Reflections ==
+'''Successes'''
-We managed to burn out one PIC chip when using a higher quality H-Bridge.  This was because of a wiring mistake that ran 12V through the 3.3V output, and into the connected laptop which caused a crash.  Fortunately, no permanent damage seems to be done to the laptop. We did not reach a point where we even truly considered trying to code a swing-up operation, which would have been really cool, but also really complicated and there simply wan't enough time.  However, the physical pendulum is still intact, so if anyone would like to work with it I'm sure professor Lynch would be willing to let you try it out.
+We broke down our project into many mechanical and electrical milestones so that we could test if parts of the pendulum were properly working before we put it all together and risk failure.
+*Mechanical
+**Milestone 1--The base of the pendulum was built and tested for stability, turning the motor on and off with various speeds. The base was mechanically robust.
+**Milestone 2--The horizontal arm was attached to the motor shaft and the motor was run at different voltages and currents to test if it had enough torque to spin the arm around. The motor ultimately provided enough torque to spin the arm quickly and the base prevented the setup from tipping.
+**Milestone 3--The vertical arm was set screwed to the horizontal shaft that was attached to the encoder and allowed to rotate freely via bearings. The whole setup was assembled together and tested for any shifting of mechanical parts that could affect the feedback control. Another mechanical block with a bearing was attached on the other side of the encoder to improve stability.
+**Milestone 4--Working Pendulum!
+*Electrical
+**Milestone 1--The circuit was constructed using an H-bridge in order to run the motor forward and reverse.
+**Milestone 2--Position control was introduced so that the motor would run but maintain the same position, even with external forces acting upon it, such as a hand trying to turn it
+**Milestone 3--The encoder was attached to the mechanical portion of the pendulum, so that it could read the position of the vertical arm
+**Milestone 4--Working Pendulum!
+'''Deterrents'''
+*We managed to burn out one PIC chip when using a higher quality H-Bridge.  This was because of a wiring mistake that ran 12V through the 3.3V output, and into the connected laptop which caused a crash.  Fortunately, no permanent damage seems to be done to the laptop.
+*We did not reach a point where we even truly considered trying to code a swing-up operation, which adds a lot of razzle dazzle but really complicates the code and there simply wasn't enough time.

@@ Line 330: / Line 330: @@
 == Results ==
-The pendulum ultimately worked!  The vertical pendulum arm was kept upright by the horizontal adjustments of the arm attached to the motor shaft. It took a couple of alterations to the code and electrical setup to get the motor to react the right way, and for some reason it only worked with a power supply, not when power was supplied from the PIC, but as the video shows, the motor does keep the vertical arm up. See the [http://www.youtube.com/watch?v=7DtFLKgNUk4 full demonstration video] [[Image:working furuta.png|thumb|300 px|A working furuta pendulum captured in motion|center]]
+The pendulum ultimately worked the first time we combined the mechanical and electrical parts together. The vertical pendulum arm was kept upright by the horizontal adjustments of the arm attached to the motor shaft. It took a couple of alterations to the code and electrical setup to get the motor to react the right way, and for some reason it only worked with a power supply, not when power was supplied from the PIC, but as the video shows, the motor does keep the vertical arm up. See the [http://www.youtube.com/watch?v=7DtFLKgNUk4 full demonstration video] [[Image:working furuta.png|thumb|300 px|A working furuta pendulum captured in motion|center]]
 ==Future Steps==