We are building an autonomous robot that will navigate outdoors. I'm 100% beginner to this. We will have 2 motors for 2 wheels for navigation. I was focusing on the h-bridge design and programming with error correction. Navigator algorithms will tell me where to go and I have to make sure that we are on the right track with some kind of feedback / control mechnanism. I looked up for some h-bridge ideas on the website (by the way I'm so glad I found this site, it rocks) like https://www.robotshop.com/letsmakerobots/node/2484 I don't know how should determine what I need exactly. I heard also there are printed circuit kits but putting one is not a problem as long as I understand it. Our motors might need up to 24 volts for necassary traction and weight. Any tip would be helpful.
Hi Asterothe, welcome to Hi Asterothe, welcome to LMR. Before you can choose a good H-Bridge for your motors, you need to collect some info about what parts they’ll be working with. You’ve already mentioned using up to 24V to supply the motors, but you’ll also need to know how much current they’ll need when working their hardest. Also, what level of control do you want over your motors? I’d assume you want to be able to drive each motor both ways at least, but do you want a fine level of control over the motor speed as well?
Thank you for the welcome and reply TeleFox. With the preeliminary tests we have some ideas about the current needs. 3 Amps should be the maximum but this number could be refined. There will be some averaga speed we are aiming for but more importantly H Birdge will control motors according to the nav system and object avoidance paramaters. If we can have a fine level of control that would be great but if it this will add much overhead, just being able to go with a reasonable speed would suffice. There’s a ramp on the way and the current need and speed will dropdown there. Somehow the H-bridge should be sophistticated enough to compensate these.
If you won’t need to change If you won’t need to change the motor direction too rapidly, a motor driver like this one should suit your purposes quite well. You could also look into working with integrated parts like the L298 h-bridge IC, but you may find it difficult to find on that will handle the current and voltage together.
Thanks for replies. I’m new to build any kind of robot. We have to this for a design project for school so I don’t have much of an option. Each motor will need up to 2 Amps from preelimanry tests. Their voltage (for each) shoudl vary between 12 V to some max less than 24V. I looked some IC controllers and I’m not sure how to pick one over another. I 'm searching LMR to see how are they used here.
The ones I found:
Freescale’s 33886 and 33887, ST’s L298 and L6205N/D, TI’s DRV8402 and DRV8800. It’s such a critical decision to pick the right one.
The robot will follow supersonic beacon signals and also avoid objects on its way, will try to complete a course by passing under beacon goals. There will be a separate navigation system that I will process and command hbridge. On top of that I need with some kind of sensors, feedback to keep track of the motors and superviose their proper function. If there’s an error microcontroller of the h bridige will adjust itself to correct the problem.
THanks for any insight it’s appreciated and I’m trying to absorb as much as I can.
