Group items tagged

stimulus-response

a plan of action

combine the best of both Reactive and Deliberative control

All of the procedures take a discrete ``gear'' to specify the speed. The reasons for this are two-fold; first, by limiting the power of the truck, we simplify the interface to children. Secondly, it allows use to calibrate the ``gears'' so that, for example, 10 seconds forward in first gear is the same distance as 10 seconds backward in first gear.

The limitation of LOGO however is the lack of feedback from the environment. There is no way of expressing an event occuring in the outside world.

Simple constructs in iLogo extend the original LOGO language with interactivity capabilities of reading sensors and transfering control to different parts of the program.

The only time you will need this term is when acceleration plays a big factor with your robot. If your robot is really heavy, or gravity is not on it's side (such as steep hills), then you will need the integral term.

The sampling rate is the speed at which your control algorithm can update itself.

To increase sampling rate, you want an even faster update of sensor readings, and minimal delay in your program loop.

Note that behaviors themselves can have state, and can form representations when networked together. Thus, unlike reactive systems, behavior-based systems are not limited in their expressive and learning capabilities.

Many Logo-based and other robotics products produced by LEGO are distributed to schools in the USA by Pitsco.

This free-range turtle does not require connection to a computer. All the controls are on board.

The Cricket is a tiny computer, suitable for all kinds of robotics projects, that you can program using Logo.

pseudocode: read left_photoresistor read right_photoresistor if left_photoresistor detects more light than right_photoresistor then turn robot left if right_photoresistor detects more light than left_photoresistor then turn robot right if right_photoresistor detects about the same as left_photoresistor then robot goes straight loop

Photovore Algorithm, Improved This algorithm does the same as the original, but instead of case-based it works under a more advanced Fuzzy Logic control algorithm. Your robot will no longer just have the three modes of turn left, turn right, and go forward. Instead will have commands like 'turn left by 10 degrees' or 'turn right really fast', and with no additional lines of code! pseudocode: read left_photoresistor read right_photoresistor left_motor = (left_photoresistor - right_photoresistor) * arbitrary_constant right_motor = (right_photoresistor - left_photoresistor) * arbitrary_constant loop

This is the 3 capacitor method.  I used this one in all my RC cars and many of the RC toys that I have taken apart use this method.

One of the easiest and most overlooked technique that can be done to lower motor noise is the twist your motor and motor power wires.  This in affect forces the magnetic fields to cancel each other out.

By placing a metal shield between your motors and radio can do wonders.  Also keep in mind that some metals shield better than others.   Carbon Steel shields several hundred times better than aluminum.  Dont use this shielding as a conductor or you may compound the problem.

1381s are CMOS voltage-controlled triggers -- these "gate" a source until the voltage is above some "trip" limit, at which point it is allowed onto a third pin

We use them as 3- or 5-volt triggers

This chip is often considered the heart of Nv net technology

I wanted to share an adaptation of the Schead v4, that I have been experimenting with. It is (for lack of a better term) a Master/Slave Schmitt Comparitor Head (M/S SC-H). With the addition of a 74 AC 240 or two (as motor drivers) and a pair of motors, you can put together an interesting little light seeking, wheeled robot with peripheral vision.

As long as the light reaching the photo-bridge of the Master SC-H is balanced, then the Slave SC-H acts as a regular, lone SC-H would. So, if one of the slave photo-diodes detects more light then the other, the inverter that controls the motor on that side changes states and is now the same as the inverter of the Master SC-H tied to the same motor. This turns that motor off and the robot will pivot around the stopped wheel toward the greater light source until the light on each sensors is balanced and the motor again begins to turn.

I am also using SCar to continue experimenting with Stacking separate Sensor/Behavior circuits onto a robot. I will post more as progress is made.

Droidmakr (Cliff Boerema) came up with an interesting idea for a light-tracking head with a form of peripheral vision. As often happens, the circuit turned into something different -- a photopopper:

All done with a single 74HC14 (the '240 being a motor driver).

I tried the same setup with the 74*240 (with an extra inverter per motor) and 7404, but the 74HC14 seems to work best.

34164s are undervoltage sensing circuits ("voltage supervisors") designed for use as reset controllers in portable microprocessor based systems. We use them as 3- or 5-volt triggers (here, 3 or 5 fills in the "*" of the part number above), as the heart of the Chloroplast solar engine design.

1381s are CMOS voltage-controlled triggers -- these "gate" a source until the voltage is above some "trip" limit, at which point it is allowed onto a third pin.

If you can't find 1381s locally, you might have better luck finding its European cousin, the TC-54 -- for details on it, see its data sheet.

Large diameter wheels give your robot low torque but high velocity. So if you already have a very strong motor, then you can use wheels with larger diameters.

But if your motor is weak (such as if it does not have any gearing), you want to use a much smaller diameter wheel. This will make your robot slower, but at least it has enough torque to go up a hill!

Wheel width. You do not want it too wide as it causes increased resistance to rotating the wheel on a surface.

"Exposing a Flaw: Shoot-Through" describes the serious problem with that circuit, especially when pulsed

Above is an improved version of the circuit, which is now PWM compatible. PWM, coast mode, and the capability to avoid shoot-through are provided by adding a fifth MOSFET (labeled Q5) to the source/ground connections of Q1 and Q3.

camera-based vision system (for light detection and navigation) two microphones, binaural hearing beat detection (allows pleo to dance and listen to music) - this feature was removed but may be added on again. eight touch sensors (head, chin, shoulders, back, feet) four foot switches (surface detection) fourteen force-feedback sensors, one per joint orientation tilt sensor for body position infrared mouth sensor for object detection into mouth infrared transmit and receive for communication with other Pleos Mini-USB port for online downloads SD card slot for Pleo add-ons infrared detection for external objects 32-bit Atmel ARM 7 microprocessor (main processor for Pleo) 32-bit NXP ARM 7 sub processor (camera system, audio input dedicated processor) four 8-bit processors (low-level motor control)