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Posted by werty on February 3, 2007, 11:12 pm
On Feb 1, 6:04 am, nucl...@gmail.com wrote:
> Hi guys,
> I'd like to show you my mobile robot based on the HandyBoard
> controller. Pls have a look athttp://robot.proof.cz
> Basic info:
> * 2 MHz microprocessor Motorola 68HC11.
> * 32 kB RAM, battery backed.
> * Drives up to 4 DC motors. I've changed the two L293D circuits
> with four SN754410NE so I can now control DC motors with up to 2A
> constant or 2.4A peak power consumption. (See H-bridges)
> * Two motor outputs can be used to control a stepper motor.
> * 16 x 2 LCD display.
> * Two fully programmable buttons, potentiometer with 0-255 range
> and a piezo buzzer.
> * 7 analog and 9 digital inputs. All of them powered for use with
> active sensors.
> * 9.6V NiCd battery pack. Charging is done by a special interface
> adapter or directly using the main board. Just connect a power adapter
> and that's it.
> * A 38kHz infra red receiver/transmitter. It's not connected at
> the moment, I'm working on a remote digital radio control.
> * 8 pin powered serial connector interface with up to 1 Mbaud
> transmission speed.
> * Easily expandable using the expansion board.
If the motor needed smooth DC , you must
use "H" bridge .
Switch mode circuits are more powerful .
You need only low cose bipolar transistors
and a little bit of inductor .
coils close to the value of the motors
inductance will work .
These self oscillating bipolar circuits will
rise 10 amps into a motor in milliseconds .
You only need to turn them off , they
turn on by themselves .
One circuit to drive the ground based motor
, positive and another to drive it negative .
This circuit is far more fault tolerant
and easier to control .
I cant understand why colleges dont teach
these better methods .
But i know why i left college after
half a semester !
The proof is in commercial stuff like
low cost power supplies .
They only use
1) single bipolar ,
2) self oscillating ,
3) switch mode , "forward" converters,
not fly backs .
I think its clever to nix the always
present problem of driving the 1 vdc base
of a bipolar .
Its just a 2nd winding on the core !
Now i can fully saturate it for 90% efficiency ,
unlike your H bridge that needs a very
large heat sink !
If your friends explain a complicated
I.C. controlled "switcher" , it is
NOT what im talking about .
Single bipolar , self-oscillating ,
and stopped by the simplist .03 amp
control .
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> I'd like to show you my mobile robot based on the HandyBoard
> controller. Pls have a look athttp://robot.proof.cz
> Basic info:
> * 2 MHz microprocessor Motorola 68HC11.
> * 32 kB RAM, battery backed.
> * Drives up to 4 DC motors. I've changed the two L293D circuits
> with four SN754410NE so I can now control DC motors with up to 2A
> constant or 2.4A peak power consumption. (See H-bridges)
> * Two motor outputs can be used to control a stepper motor.
> * 16 x 2 LCD display.
> * Two fully programmable buttons, potentiometer with 0-255 range
> and a piezo buzzer.
> * 7 analog and 9 digital inputs. All of them powered for use with
> active sensors.
> * 9.6V NiCd battery pack. Charging is done by a special interface
> adapter or directly using the main board. Just connect a power adapter
> and that's it.
> * A 38kHz infra red receiver/transmitter. It's not connected at
> the moment, I'm working on a remote digital radio control.
> * 8 pin powered serial connector interface with up to 1 Mbaud
> transmission speed.
> * Easily expandable using the expansion board.