Robot Efficiency & other Robot stuff

[williB]

would it be possible to store the energy from the reverse EMF of a stepper, as it is running.
i was just wondering if i could save power in battery powered robot with a very large electrolytic capacitor connected across the main power supply.

 

[Optikon]

Re: Robot Efficiency

would it be possible to store the energy from the reverse EMF of a stepper, as it is running.
i was just wondering if i could save power in battery powered robot with a very large electrolytic capacitor connected across the main power supply.

yes, one form of it is called regenerative braking. A capacitor across mains supply will not save any power. Capacitors just store energy.
To make the system effective, you will have to get that energy back into the battery. When the vehicle is moving but the drive is not driving the motors, the motors can act like generators and that energy can be recovered but it is more complicated than just using a capacitor.

 

[williB]

ok but when u turn off a coil in the stepper,, and redirect the back EMF with diodes twards the positive supply terminal,, where does it go..
i can only assume that it is stored in the powersupply caps..
so that is what i had in mind with the battery setup..

 

[williB]

Ive just got my robot moving for the first time..last night..
i am using two steppers ,one for each back wheel.
the two steppers are connected together..ie driven by the same drive transistors..i will drive them seperately after i get four more IRF 510's
i realized thet i had to run the second one in reverse so i made the proper connections
something very strange happened ..
When all power was off and i turned one wheel ..the other wheel turned in the same direction..!!
so i turned it the other way .. the other wheel turned in the other direction!!...hmm..sort of an electronic mini car differential

 

[Nigel Goodwin]

Ive just got my robot moving for the first time..last night..
i am using two steppers ,one for each back wheel.
the two steppers are connected together..ie driven by the same drive transistors..i will drive them seperately after i get four more IRF 510's
i realized thet i had to run the second one in reverse so i made the proper connections
something very strange happened ..
When all power was off and i turned one wheel ..the other wheel turned in the same direction..!!
so i turned it the other way .. the other wheel turned in the other direction!!...hmm..sort of an electronic mini car differential

An electric motor works backwards as a generator, steppers do this as well as conventional motors - EPE did an article on a batteryless torch using a stepper motor the other year.

 

[williB]

i had a neighbor that called a flashlight a torch.
over here , a torch is what the croud was using to find Frankenstein at night.. :shock: :wink: :wink:

 

[Optikon]

i had a neighbor that called a flashlight a torch.
over here , a torch is what the croud was using to find Frankenstein at night.. :shock: :wink: :wink:

yes... HA HA... I always smile when I see "torch".. Frankenstein is precisely the image that pops into my mind! LOL

 

[williB]

i had a neighbor that called a flashlight a torch.
over here , a torch is what the croud was using to find Frankenstein at night.. :shock: :wink: :wink:

yes... HA HA... I always smile when I see "torch".. Frankenstein is precisely the image that pops into my mind! LOL

Yeah mine too !! :lol: :lol:

 

[Nigel Goodwin]

i had a neighbor that called a flashlight a torch.
over here , a torch is what the croud was using to find Frankenstein at night.. :shock: :wink: :wink:

The English are far too civilised for such primative thoughts :lol:

 

[williB]

i had a neighbor that called a flashlight a torch.
over here , a torch is what the croud was using to find Frankenstein at night.. :shock: :wink: :wink:

The English are far too civilised for such primative thoughts :lol:

but are they good spellers :shock: :wink:

 

[Nigel Goodwin]

but are they good spellers :shock: :wink:

Not me anyway 8)

 

[williB]

Nigel looky what i found while roaming around the net..

what i found particularly interresting was the Pic net USB page

**broken link removed**

could not an ambitious person devise a USB pic programmer with this info??

 

[Nigel Goodwin]

Nigel looky what i found while roaming around the net..

what i found particularly interresting was the Pic net USB page

**broken link removed**

could not an ambitious person devise a USB pic programmer with this info??

Why not just use the details for the PICKit 1 on MicroChips website?, it gives the circuit, source code for the 745, and source code for the VB program to run on the PC.

Basically both the PICKit 1 and the PIC Net design use the code from the original 745 application note.

 

[williB]

I thought that i would show yall my robot car .

 

[williB]

this board takes the signals from the PC .. later on from the Pic..
and drives the steppers..

 

[williB]

I think i should tie the FET inputs lightly to ground...lol. Just in case..
oh a 330 uF capicitor across the power supply eliminates the spikes, and does'nt round the edges too much..

 

[williB]

this is my new setup.. that is the ICSP cable on the front..cool huh..
my next step is to drive the steppers with just the pic..

 

[williB]

i wanted to post this page because somone asked about the sharp ir sensor..

http://www.robotprojects.com/sensors.htm

 

[williB]

ya know those polaroid sonar sensors , this page talks about how to use one..

http://www.robotprojects.com/sonar/sonar.htm

 

[bloody-orc]

hey what steppers did you use and how much current\voltage do they take?
i´m thinking of mooving my own robot with steppers but when i put my stepper running on the table without any wheels or anything then it seems that the stepper is to weak i have a 5V\0.5A stepper and controller is uln2003a and pic