DASL: Weekly Update 2007-07-19

Because the DASL’s choice supplier is Jameco I have changed the choice of Opamp’s that I am using, because the ones I wanted were not going to be in stock until 2007-12-01

Because the DASL’s choice supplier is Jameco I have changed the choice of Opamp’s that I am using, because the ones I wanted were not going to be in stock until 2007-12-01.  Please see the parts list below for the new Opamps.

 

Item Description

Manufacturer

Supplier

Product Link

MFG: Part Number

Supplier: Part Number

Price (2007)

Quantity

Low input current Opamp

Microchip Co.

http://www.jameco.com/

MCP6002-I/P

MCP6002-I/P

311001

$0.45

10

High Output Current Opamp

Major Brands

http://www.jameco.com/

LM675T

LM675T

120926

$4.85

10

 

 

Analog Motor Driver:

 

 

See Figure 1 below for the schematics for the motor driver for the inverted pendulum.  It takes an input between -10 and 10V, the range of the NI-USB-6211 DAQ, and outputs a range of -2.5V to 2.5V to the motor.  The maximum input current is less than 1mA and the maximum current through a 4Ohm load is less than 0.75A.  Please note that this system requires a 15V motor.  See Graph 1 below for the outputs of the schematic below for a voltage sweep from -10V to 10V.

 

Figure 1

 

Graph 1

 

See Figure 2 below for the test board using the LM675 setup as seen in Figure 1 above.  Please note that this setup has yet to be tested with the motor that is going to be used.  Further tests will be done next week to see if it follows the expected curves in Graph 1 above.  Please note that I believe that U1 and U2 will need heat sinks.

Figure 2 (Analog Motor Driver With 2x LM675)

 

Figure 3 (Analog Motor Driver With 2x LM675)

 

Figure 4 (Analog Motor Driver With 2x LM675)

 

Figure 5 (Drive Current for Motor Driver)

 

Figure 6 (Source “command” current in mA {0.4mA})

 

 

 

 

 

 

Pendulum Cart:

 

I have constructed the cart for the inverted pendulum.  Please see the pictures below for a description for where the rest of the parts will go.  Also please see Figure 7 below for the schematics for the built cart below.

 

Figure 7 (Schematics for the cart)

 

 

Figure 8 (Four 2”x4” blocks with hole measurements)

 

Figure 9 (After Holes Cut)

 

Please note that in be blue and red circles there are holes drilled so that a 1/8” shaft can move freely.  A 1/8” brass rod will be used to be the axle of the second wheel, with the encoder being placed behind the plastic.  The second wheel will be in the hole where the blue circle is.  The red circle is where the pendulum will be.  The pendulum will also use a brass rod and an optical encoder connected on the other side of the plastic.

 

Figure 10 (Cart Front View)

 

Please note that there will be a rod on the back of this cart that connects the cart to a central pivot

 

Figure 11 (Cart Top View)

 

Figure 12 (Cart Side View)

 

Figure 13 (Motor)

 

Figure 14 (Back)

 

Goals For Next Week:

 

Next week my goals are as follows:

  1. attach the optical encoders to the cart.
  2. attach the pendulum to the cart
  3. attach the arm to the cart
  4. finish the analog motor driver
  5. get into contact with Kathie Donahue in regards to weekly payment because I have not heard back since her last email last week.