CE Project: CE Bot [PART TWO]

[xheavenlyx]

@Raj

I was just thinking, that we need to have an approximate idea of the total weight that the chases and wheels will support. It would help in the designing and fabrication of these parts. It would also help in the stress calculation and other equivalent stuff.

Thats what I said we have to do. Its the most important thing, and it IS NOT EASY!

@Kinetic

Ok, I will need some time to think of this. If you are interested to do the chasis rite now. Then I want you to read about the rocker-bogie design and incorporate in your present idea. Here are links:

WIKI: Rocker-bogie - Wikipedia, the free encyclopedia
PDF: http://kipr.org/papers/robotics02.pdf

@Ash.

Ash, please, I am going crazy here. I need to know what the robot will be used for and in which environment. Again, its like building a house without knowing if we need a slant roof for snow or a cement house for tropics.

IF robot is used to mapping in deserts THEN it has to be a bit bigger, more than 20 KG and that will depend on Sensors, environment and abilities.

IF Robot is used in forest areas for trespassing violations (Border security, airport security) then it has to be long lasting, sturdy and weather proof. Everything changes.

And so on...

Ash, you know I was confused before too. So are we SURE we will be going with Remote Sensing, Mapping robot? For laaaaarge areas and weather intensive, can survive for days using solar power and GPS (I have a GPS module that can be sacrificed)? Wont that be a good project? We already have 15 year old's building useless sensor bots...too comon. We need a something that can SURVIVE! What do you think of this idea?

[bayazidahmed]

Hi guys!

After a long time, huh? I remember promising to do the block diagram and then left, couldnt help it.

I was going through all the posts of CE:Bot and this CE:Bot 2. And whoa you people have done a load of good job (and I feel that everyone here is smitten by the drive system ).

Anyways, going into the topic, my knowledge(the areas where I can help) includes Sensors, Processor(s), Drive System, Power Supply Unit(s) and Communications.
But of these I personall dislike the last two(Power Supply Unit(s) and Communications), which leaves me with three topics.

1. Sensors - I dont have practical access to any of the sensors mentioned, but I do have a good knowledge and a very good googling capability. Which means I will not be able to provide the exact details of how each thing works, but can help you guys in searching for the datasheets, and any other information you want.

2. Ah, I feel at home when discussing them. My true love, programming *blush*. I remember reading somewhere in the discussion regarding the language to be used, Python (and was Ruby also discussed?). Why? Firstly, Do they have compilers for RTOS, linux and PIC/ATMEL? I dont think so. Secondly, Do they support assembly langauge instructions. Again, I dont think so. Third, Do they support low level instructions? Again, I dont think so. Then why python? The only language that can be effectively used in this case is C/C++. And regarding the use of either PIC or ATMEL, both are good, anyone of them can be used. I think ATMEL is easier and powerful to work with. My suggestion is to use each PIC/ATMEL for each module (like for the drive sstem, one powerful micro-controller, for each sensor, smaller micro-controllers for which the requirement of RAM, ports, etc... is not much).
I'll divulge in detail when the turn comes (Maybe xhx will get angry at me for discusing processors when the current turn was for sensors).

3. I think ash's idea of indepently powered wheels is very good, which gives u an excellent control, flexiblity, durability, and easy to program.

I think its enough for now, the post size is getting longer and I am getting sleepier .

Waiting for comments...

[ash]

Originally Posted by xheavenlyx

@Ash.

Ash, please, I am going crazy here. I need to know what the robot will be used for and in which environment. Again, its like building a house without knowing if we need a slant roof for snow or a cement house for tropics.

IF robot is used to mapping in deserts THEN it has to be a bit bigger, more than 20 KG and that will depend on Sensors, environment and abilities.

IF Robot is used in forest areas for trespassing violations (Border security, airport security) then it has to be long lasting, sturdy and weather proof. Everything changes.

And so on...

Ash, you know I was confused before too. So are we SURE we will be going with Remote Sensing, Mapping robot? For laaaaarge areas and weather intensive, can survive for days using solar power and GPS (I have a GPS module that can be sacrificed)? Wont that be a good project? We already have 15 year old's building useless sensor bots...too comon. We need a something that can SURVIVE! What do you think of this idea?

My good friend, we have to realise that this is our first prototype! Haha.. for sure, no robot design is perfect on the first try. We need to start small, then scale up. Remember, our robot is designed to be modular, so we can always enlarge the size later. We need to focus on the functionality first, rather on reliability and survivability. Once we score on the sensors, communications and movement over rough terrain, we would have completed our first objectives. So indeed, we are still doing a remote sensing and mapping robot, but we dont need highly sophisticated robot to do that yet.

After we know they work, we can start focusing on secondary objectives. We never really discussed about long term survivability until recently. I gave an estimate of 1 hr when we first started, which is long enough to collect some sort of data. If we manage that, then we can move on to install solar panels and other added enchancements. The fact that we are using your laptop means it provides is with flexibility on configurations. At least we do not have to fabricate that many new PCB's

Originally Posted by bayazidahmed

1. Sensors - I dont have practical access to any of the sensors mentioned, but I do have a good knowledge and a very good googling capability. Which means I will not be able to provide the exact details of how each thing works, but can help you guys in searching for the datasheets, and any other information you want.

2. Ah, I feel at home when discussing them. My true love, programming *blush*. I remember reading somewhere in the discussion regarding the language to be used, Python (and was Ruby also discussed?). Why? Firstly, Do they have compilers for RTOS, linux and PIC/ATMEL? I dont think so. Secondly, Do they support assembly langauge instructions. Again, I dont think so. Third, Do they support low level instructions? Again, I dont think so. Then why python? The only language that can be effectively used in this case is C/C++. And regarding the use of either PIC or ATMEL, both are good, anyone of them can be used. I think ATMEL is easier and powerful to work with. My suggestion is to use each PIC/ATMEL for each module (like for the drive sstem, one powerful micro-controller, for each sensor, smaller micro-controllers for which the requirement of RAM, ports, etc... is not much).
I'll divulge in detail when the turn comes (Maybe xhx will get angry at me for discusing processors when the current turn was for sensors).

Welcome back, again Actually, we will still be using other languages. The beauty of Python is that it can work well with C/C++, or other langs. We use Python for high level non-critical tasks in the laptop itself. Python gives us a lot of ease and flexibility, and allows us to change code faster if we need to. It is also portable.. works in any platform (yes, it can run in Linux!). For critical processes, we will stick to ASM and C/C++. Though, xhx knows more about its application in CE Bot than I do

Have you given Python a try? its quite awesome..
Python Programming Language -- Official Website

Heres a link to applications of python in robotics:
Pyro, Python Robotics: Pyro

For sure we will use a uC for each module. Its just that they are all interfaced together to the laptop (along with data & image processing stuff). The laptop also acts as the interface between the modules and the computer host (since we may choose to use remote control).

3. I think ash's idea of indepently powered wheels is very good, which gives u an excellent control, flexiblity, durability, and easy to program.

I think its enough for now, the post size is getting longer and I am getting sleepier .

Waiting for comments...

Yeah, xhx's Rocker-bogie idea works well with the independent motors. Though, we'll have a nightmarish time figuring out how to supply enough power to them

[KINETIC_JOULES]

Originally Posted by xheavenlyx

We already have 15 year old's building useless sensor bots...too comon. We need a something that can SURVIVE!

I was just going by what y'all were saying. Not like it's entirely my fault. I'm designing what you say to design. And they were just experiments anyway. I could always do something different. That's all you have to say. I'm not going to be immature and say I quit the team, because that doesn't solve anything, but I want to feel like I'm doing something important and productive, and not do something in vein for you to just laugh at. If it's useless. . . why didn't you tell me that to begin with? Why didn't you say do something different? If what I'm trying to contribute is useless. . . what's the point of having me around?

[ash]

Originally Posted by KINETIC_JOULES

I was just going by what y'all were saying. Not like it's entirely my fault. I'm designing what you say to design. And they were just experiments anyway. I could always do something different. That's all you have to say. I'm not going to be immature and say I quit the team, because that doesn't solve anything, but I want to feel like I'm doing something important and productive, and not do something in vein for you to just laugh at. If it's useless. . . why didn't you tell me that to begin with? Why didn't you say do something different? If what I'm trying to contribute is useless. . . what's the point of having me around?

You know, that was an innocent mistake. I dont think xhx knew you are 15.. what a horrible coincidence.

Chill, Tyler. He meant amateur robots that have no real objectives and profound benefits to society, thats all. Your designs have nothing to do with his statements. I'll bet you that the next time he logs in, he'll be apologizing his heart out for the misunderstanding

Carry on with it. Seriously.. your designs are kick ass. Here's a lego design with some changes made. The red objects are the DC motors, and the blue the suspension. I have no idea what steering method works with this configuration.. maybe independent servos? Thats pushing our luck, though.

[KINETIC_JOULES]

Originally Posted by ash

You know, that was an innocent mistake. I dont think xhx knew you are 15.. what a horrible coincidence.

Chill, Tyler. He meant amateur robots that have no real objectives and profound benefits to society, thats all. Your designs have nothing to do with his statements. I'll bet you that the next time he logs in, he'll be apologizing his heart out for the misunderstanding

I'm sorry. . . I'm just stressed. *tears* I didn't mean to sound like that. Forgive me?
And the design is GREAT! Really good job! That's what I thought you were talking about with the axles. . . but it was too late to change it in sketch up.

[ash]

*thumbs up* its cool

I want to try doing the Rocker-bogie design that xhx suggested on MLCAD. The good thing is I can colour-code lego components, so its easy to see which subsystems is what. If someone has enough lego pieces (as well as the electric stuff), they can construct a mini model of CE Bot in real life!

[KINETIC_JOULES]

Originally Posted by ash

*thumbs up* its cool

I want to try doing the Rocker-bogie design that xhx suggested on MLCAD. The good thing is I can colour-code lego components, so its easy to see which subsystems is what. If someone has enough lego pieces (as well as the electric stuff), they can construct a mini model of CE Bot in real life!

That would be cool! I don't own any legos anymore. . . I lost them years ago. *thinks for a minute* wait! Yes I do!

[gohm]

Ash, I would only share a servo for both sets of steering. Simple, more reliable and less weight. You'll only need to trim one servo that way.

[raj87verma88]

@ Ash: A good design buddy. Let me see, You have a rack and pinion on both sides. Just wondering, why the middle set of wheels do not have those spring shockers. From your designs it seems that you want the bot chases in the lines of a Baja or dune buggy. That is a good idea, but we can try others too and settle for the one which is best.

@ Tyler: Wow, quite a big misunderstanding between two team members. I know that Ash has already calmed you but I have to say something. Tell me has anyone ever said that you are unimportant to the team or to CE in general. Have we not encouraged you in your designs. We know you are not an engineer and at the age of 15 we don not expect you to have the knowledge and experience of one. That is why you were given the job of designing. Frankly speaking, your designs are good but when we start fabricating the bot we will have to make a few or more modifications on your designs because we will have to consider the forces and calculate stuff and other things. And as the bot completes you will gain a lot of knowledge and experience. You are so lucky that you will gain such an experience at 15 while we in our 20s. I wish I was your age. In the end I apologize on behalf of CE and all its members if in any way you have been wronged. You are going to join an engineering school in the future and it is our duty to answer your queries so that when you join a univ. you will be ahead of your mates. This is the idea of CE, to help and support each other and have co-operation among ourselves.