Steering servo and DC motor with ESC
Vladimir059
Posts: 9
Hello everybody. My name is Vladimir and I’m beginner in Basic Stamp2. As I’m very lazy to do a home cleaning and my apartment serves me also as a workshop so I decided to make my life easier and build robot vacuum cleaner similar to IRobot’s·· “Roomba”. Buying such things from a store offends me as designer and decided to make it myself.· I have no problem with designing mechanical parts and assemblies, I don’t think I will have any problems with electronics, but I expect some difficulties with programming.· I’m currently reading “Basic Stamp Syntax and Reference Manual”, but to start with it I need a sample of wandering program. For my “MonsterVac”· I’m going to employ steering servo. For propulsion I’m going to use DC motor with a hobby ESC- forward / reverse (hobby ESC using the same signals as standard hobby servo)· and two infrared sensors to collision avoidance. This is my basic set up. In future I’m planning to hook up a metal detector for searching and careful cleaning of·metal shavings.· I checked up Parallax web site and found that all robots mentioned there using two continuous rotating servos. For my application such scheme not acceptable I have to employ steering wheels and due to relatively heavy structure I have to use powerful DC motor and accordingly ESC.
So if somebody have a sample of program to meets all this requirements, please let me know. I’m also appreciate for any input device subroutines which can improve “sensing” of my “devil machine” as ultrasonic sensors, whiskers, co-processor, wireless video camera, LCD display to monitor cleaning progress and so on.···
Thank you in advance
Vladimir.···
So if somebody have a sample of program to meets all this requirements, please let me know. I’m also appreciate for any input device subroutines which can improve “sensing” of my “devil machine” as ultrasonic sensors, whiskers, co-processor, wireless video camera, LCD display to monitor cleaning progress and so on.···
Thank you in advance
Vladimir.···
Comments
Robots often prefer to change direction and change speed.
I suspect that you want to get started with what you have available, but you might look at a good H-bridge and consider a couple of DC motors that are lower in RPM [noparse][[/noparse]100s of RPMs, not 1000s]
You don't have to use an ESC for power. Parallax's new H-bridge will easily go up to 1/2 horse power. And will allow for directional and speed changes too.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Radio controlled electronic speed controls (ESC) come in two basic types. One is intended for aircraft (airplanes and helicopters), and the other for automobile (car and truck) or marine (boat) use. Indeed ESC's for airplanes, and some of those designed for car/boat use are forward only. However, there are also ESC's made for auto/marine use that offer reversing. Here is one such unit:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJM28&P=7
Regards,
Bruce Bates
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Though I am also relatively new to robotics, I am using a different platform than the boe-bot from Parrallax. I started the hobby by using the basic kit from Arrick robotics called ARobot.· It also uses the basic stamp2 etc.,· but has a steering servo and one geared DC motor for propulsion.· Perhaps this might give you some ideas. Plus on the site they have posted BS2 programs for wandering.· It was a great start for me, but I have since included many Parrallax modules such as Ping and EMIC that all works great.·
Anyway, just another avenue for you to research.
Bob
Vlad
PS Thank you Bob. I checked up mentioned you web site and found information very useful but ARobot using PIC 16F84 as coprocessor I’m not sure that my ESC has the same PIC. Adapting the program for my ESC is beyond me right now. I hope, I will be able to handle such tricks soon, but for this moment I need something “from the shelf».
Vlad
I have been working on a project using ESC speed controllers. One of the first things that I noticed was that all the power leads are inter connected, (all red leads have continunity - all black leads also)·the ESC back feeds power to the servo plug, thus being able to supply power to the basic stamp via the servo connection. I am just controlling the speed of the motor and am using a one direction ESC (Tower hobbies ICS-490 F) $14.00 so their is a chance that this type of ESC only acts this way.
FYI
Mike W
BTW, yes.... You can either propell two wheels at different speeds for steering OR you can have one propulsion motor for an axle and one steering servo on a third wheel or another axle.
Two wheels, two differentially controlled motors seem to over tighter control. But tippy at higher speeds.·
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I do understand now that you already· have your ESC and probably have a design in mind.
The BasicStamp will control it with Pulse Width Modulaton {PWM}, same as the R/C control.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 3/19/2006 11:05:00 AM GMT
The Synatx and Reference Manual is indeed good reading, but based on your initial post, I would suggest reading the "What's a Microcontroller?" text (free) to get a better "real world" view of how to control things with a Stamp. While some of the previous suggestions may be helpful, I get the impression that design is not your current concern...programming and interfacing probably are.
Good Luck!
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Truly Understand the Fundamentals and the Path will be so much easier...
Post Edited (Tom Walker) : 3/20/2006 3:57:24 PM GMT