Let's Make Robots!

rhex

hi guys i am fabricating a modified form of a rhex. i am a mechanical engg graduate and i know nothing abt electronics . can you guys tell wat are the electronic configurations that are requied. like pic or pid or ic8085. wat sofewares can be used for interfacing. wat kind of material are to be chosen for leg design . the budget is within $400.

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oh thank you very much mr ignoblegnome.i find it very useful for me.soon i will submit my design and i expect your comments on it for its development. thank you very much again sir.

There are many processors that could work. I would pick the one that will be most comfortable for you to program in. There are a lot of Arduino and Picaxe users on this site, but other processors as well. The Picaxe and Basic Stamp can be programmed in Basic-like languages, which may be more approachable for you if you are not an experienced programmer. There are also small form factor PCs, which would allow you to use a Windows or Linux OS. There are many support sites for the Arduino and other processors that you will find on the Internet. A raw PIC is possible as well, but you need to be sure you have the skills and tools to program it.

Stepper motors require special drive circuitry. You have to send a series of pulses to each coil in a certain sequence to control stepping forward and backward. This is different from a standard DC motor that can be driven forward or backward with what is called an H-Bridge circuit. Another common approach is to use a servo motor that has been modified for continuous rotation. This has the advangage of being able to be driven from a single processor output.

There are various sensors for obstacle avoidance/detection. You can use an ultrasonic type like the SRF05 or PING. There are infrared (IR) sensors you can buy or build. One of the robot manufacturers on this site, DAGU, has an IR based compound eye that is good for object tracking. Another approach for simple obstacle detection is a contact switch. This is simply a bumper that activates a switch telling your robot it has contacted something. You may be able to mount your sensor on a servo or even a pan/tilt platform so you can scan around and up and down.

Each sensor type has its pros and cons. IR sensors may not work well in bright light. Ultrasonic sensors won't "see through" glass or other transparent objects. Contact switches require your robot to actually touch the object.

There are lots of example robots as well as tips and walkthroughs on this web site. Try searching and seeing what can help. Have a read through the "Start here" robot for a step-by-step introduction to a simple autonomous robot. 

i am building it on rhex 0.0 platform no idea abt gear transmission. my design is under progress. i will upload my design sooner may be within a week. everyone here is saying to use PIC. but i am a beginner. can i use it or an arduino instead.

where can i download programming softwares for arduino and for other controllers 

tasks---the RHEX should check whether the obstacle is small .if yes, then it should move over it. if not it should turn around  and take another path.regarding battery 9v battery.wat to do?

 

actually i am trying to build it with stepper dc motor. it should avoid obstacles,climb small things like stones ,steps.

dimensions say length 30cm.height 20cm,breadth20cm,......then which sensor is better?

wat abt electronics can i use pic or arduino(i just read abt them in the forum) ?how to interface?programming guide?kit for it?

then  my main modification is that the  curved legs should have extra suspension system  and springs so that the motion can thrust it further

A little more information on what you are trying to accomplish would be helpful. I found some info on RHex at this site:

http://ai.eecs.umich.edu/RHex/RHexversions.html

What are the specifications you are building to? What you need for electronics, processors, and software depend a lot on your physical platform and what you want it to be able to do.

For example, the original RHex 0.0 platform had six 20W DC brushed motors with 33:1 gearheads for locomotion. Is this what you have or something different?