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Rob Turner

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Rob Turner - Coon Rapids, MN

CitCon 001

Project Name: Solarplex (City-State)
Robot Classification: City Constructor
Type: Tread
Purpose: Construct walls out of foam bricks.
Controller: Scenix SX28 microcontrollers (2), SSC II, Vector Compass, Lynx (TM) Transceiver, Desktop/laptop computer.
Software Development Environment/Methods: Assembly for SX microcontroller, C++ computer interface for independent servo motion, City Director - a C++ program that controls the overall construction of the city.
Sensors: G2D02, IRLED/Sensor (7)
Actuators: CS-51 standard servos (3), CS-72 heavy servos (3), DC motors from a Tonka (TM) Toy Tractor.
Size: 8" Tall, 5" wide, 10" long.
Weight: 6 lbs.
Power source: 9.6 V, 3.2 amps provided by two AA NiMH battery packs.
Construction history and operation: I am currently working on this unit and naturally it's taking longer than I expected, but I expected that. The hold ups I've experienced so far:
- Problems interfacing the desktop to the unit using C++ (fixed).
- Arm not strong enough. (used bigger servos, fixed).
- The toy base not turning under load (used larger base, fixed).
The next step is to integrate the wheel sensors and the Linx (TM) transceiver. This page will be updated on a monthly basis.
Status: Construction in process.
Location: Rob's bench.
Future Strategies: Integration into a construction unit for Solarplex. More details on City-State construction when I actually start building them.

ARBi

Type: Biped
Purpose: To gain a working knowledge of Bipedal locomotion.
Controller: Basic Stamp II, SSC II (2).
Software Development Environment/Methods: Basic for the Stamp II, VB computer interface to independently move servos.
Sensors: None
Actuators: 15 CS-11 servo motors, 7 for each leg, 1 to shift battery pack weight.
Size: 8" tall, 3.5" wide
Weight: 0.8 lbs.
Power source: 6V 1 amp Gel-Cell (Sealed lead-acid)
Construction history and operation: The objective of this project was to develop a two legged, walking robot. To this end ARBi was rebuilt 9 times, using different sized servos. The final design (pictured) was constructed using 3/8" Acrylic rods, micro servos (15), and SSC II servo controllers (2). ARBi's motion and balance was determined by configuring the position of each servo using a desktop computer running a Visual Basic program specifically designed to interface with the SSC IIs through the Basic Stamp. 14 "snap shots" were taken of 2 steps. These shots were attached together in the stamp programming using the proper time intervals as glue. Using this method produced two steps that the robot could take, but these steps could not be duplicated, so sometimes the robot walked, sometimes it fell down.
The obvious solution would be to use some sort of sensors to balance the robot. Strain gauges would not work because the plastic flexed too much. Flex sensors looked promising, but the pressure scale was logarithmic with an error margin that was too great. Switches did not produce enough resolution. Another problem was that the servos were too "spongy" meaning they could be pulled a few degrees out of position before they would respond. These few degrees multiplied by 15 becomes quite an error factor and is probably the real villain in this project.
Status: Discontinued, no immediate plans to continue.
Location: Rob's Robot Grave Yard.
Future Strategies: Future ARBi's would require design changes related to motors, sensors and programming techniques. I believe the overall design is sound, but I would use small DC motors with worm gear drives instead of servos. I would look into accelerometers and piezo pressure sensors for balance. Lastly future ARBi needs the ability to teach itself to walk, most likely with the help of external sensors and computational assistance.

HiBot

Type: Hexapod
Purpose: To gain a working knowledge of hexapedal locomotion.
Controller: Basic Stamp II with rampack extension, SSC II (3), Abacom Transceiver, Remote control unit.
Software Development Environment/Methods: Basic for the Stamp II, VB computer interface to independently move servos, Basic for the Stamp II in the remote control.
Sensors: None
Actuators: 18 CS-72 servo motors, 3 for each leg.
Size: 15" tall, 18" wide, 22" long.
Weight:10 lbs.
Power source: 6V 10 amp Gel-Cell (Sealed lead-acid), 12V 1.2 amp Gel-Cell (2).
Construction history and operation: The objective of this robot was to construct a six legged platform for future development of manipulators and sensors. Hibot was reconstructed 3 times, initially using standard servo motors and body segments, finally settling on the heavier servos with no body segments. The final design (pictured) was constructed using 1" and 3/4" Acrylic rods, heavy servos (18), and SSC II servo controllers (3). Hibot's motion was created using a desktop computer running a Visual Basic program that interfaced with the SSC II's through the Basic Stamp. The walking motion is merely a series of "snap shots" run together. This robot also had a remote control unit built around a Sega video game controller and two Abacom Transceivers, which allowed for remote control up to 30 meters.
Hibot actually carried out the walking functions it was suppose to, however the robot was slow and unstable.
Status: Discontinued, new version in long-term planning phase.
Location: Rob's Robot Grave Yard.
Future Strategies: Legs would be added increasing the number to 8. All legs would receive another "elbow" joint and would be reconfigured to resemble a spider. Foot sensors would be added, and the overall size might be increased. Servos would be replaced by DC motors with worm gear drives.

PCB Plotter

Type: Printed Circuit Board Plotter
Purpose: To quickly and easily make printed circuit boards
Controller: Three axis, 2 amp step Motor Controller from Camtronics hooked to the printer port of a Pentium 133 Mhz.
Software Development Environment/Methods: DANCAD/DANCAM program, Aries lite.
Actuators: 3 1.8 degree Bipolar stepper motors.
Size: 12" x 11" x 8"
Weight: 5 lbs.
Power source: 220 Watt computer power supply.
Construction history and operation: In a continuing search for quick and easy printed circuit board manufacturing, I turned to Camtronics' three-axis two-amp controller and a ultra-fine tipped permanent ink marker to produce plots directly from the computer via the printer port. I used acrylic square rod to construct the base and printing plate for the machine, two1/4-20 threaded rod used as worm gears connected to stepper motors to drive the plate in the X/Y directions. The copper-clad board was taped to the base-plate using double-sided tape. As the copper-clad board moves a pen lightly drops on the surface and draws out the printed circuit board pattern. It worked fairly well, but had a hard time retracing lines due to slop. I used DANCAD coupled with Aries Lite to produce the pattern that went onto the copper. The ink pen was a little wide, but when I thinned down the pads before drawing them I got a trace that fit through the gap between the pins on a DIP package.
Status: Discontinued, printer-based version scheduled for construction this summer.
Location: Rob's Robot Room, top shelf.
Future Strategies: DANCAM was a pretty good program that did a lot of cool things, but it was DOS based and I would prefer Win95 or higher (Yeah I'm like that), plus the machine I built also had too much slop. With this in mind it is my intention to modify an HP plotter to accept permanent resist ink pens (This has been successfully done by Ron Jesme). Though I may never build another pen-plotter, I do have plans to build a machine that drills and cuts acrylic rod for my robots using the CNC methods I learned. I intend to use an SX microcontroller as the interface chip between the unit and the serial port of a Windows-based computer. I'll probably make an interface program using VC++ 6.0.