Society of Robots - Robot Forum

General Misc => Misc => Topic started by: Ro-Bot-X on August 14, 2007, 05:04:36 AM

Title: My robot Eric
Post by: Ro-Bot-X on August 14, 2007, 05:04:36 AM
This is the big robot that I'm curently building. It's name is Eric, because it is based on a ER1 kit made by Evolution Robotics. I have used the parts from the kit to build the base of the robot, but instead of a laptop I am using a mini ITX motherboard, Via Epia 800, housed in an old Compaq PC case, mounted on top of the base. The webcam is mounted on a pan/tilt head, together with a ultrasonic sensor, a PIR sensor (not installed yet) and a LED bar as a mouth. The robot also has a 6 DOF arm (only 5 installed at the moment), with a hand made using Legos, featuring adaptive fingers.

Technical data:

- Brain: Via Epia 800 mini ITX motherboard, with 256 MB RAM, a 1 GB Compact Flash Card, 12V ATX power adapter; the drive is controlled by ER1 RCM; the arm is controlled by an OOPic-R board (not a good choice, needs to be replaced); a USB wireless adapter allows for remote operation.

- Software: Win 98 and ER1 software for video recognition, driving and IR distance sensors, MS Speech software, a custom aplication writen in Python for behaviours and arm/head controll.

- Drive: Stepper motors from ER1 kit, no encoders; 1 caster wheel from ER1 kit, in the back of the robot.

- Power: One 12V 7Ah SLA battery for driving and electronics; one 6V 4Ah SLA battery for servo power.

- Arms: 2 arms, one with 6 DOF and one with 4 DOF (not built yet).

- Head: Pan and tilt servos; the head holds the webcam, the LED bar graph as a mouth, a US sensor, a PIR sensor; I am also considering mounting the microphone.

- Sensors: 4 Ping Ultrasonic sensors (3 on the base, 1 on the head), 4 Sharp IR sensors (3 in the front, 1 in the back), 1 Eltec PIR sensor (on the head), 1 Devantech Compass sensor (inside the body), 1 IR barier sensor (on the right hand), 1 Hall sensor (on the left hand)...

Right now the robot can be operated wirelessly or it can roam around the room saying the names of the objects it recognizes. It uses only the Sharp IR sensors to find obstacles. I have a problem with the Ping Ultrasonic sensors because the OOPic-R board can't read them. I will have to change the microcontroller to ATMega32 (just because I have one) and rewrite the code. It would be easier to change the sensors, but I can't buy new ones at the moment. PIR and Compass sensors are not installed yet; mainly because I was trying to solve the US sensor reading. Same goes for the IR barrier on the hand. The arm needs to be reshaped and the second arm be built. The second arm's task will be to open the refrigerator door, so it will look like a hook. The Hall sensor mounted on the hook will detect the contact with the door. For the moment, I can wirelessly operate the robot to go to the refrigerator, open the door, grab a Pepsi can and bring it to me.

Here is a picture of the robot:
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You can see more pictures here:[email protected]/sets/72157601435781333 ([email protected]/sets/72157601435781333)

Let me know if you like it!
Title: Re: My robot Eric
Post by: HDL_CinC_Dragon on August 14, 2007, 05:50:22 AM
That looks pretty good! Almost looks professionally manufactured hehe :) I think its the computer tower :p

Great work man :) Keep it up
Title: Re: My robot Eric
Post by: Admin on August 14, 2007, 08:51:27 AM
I believe posted movies are in order ;D

Your design is interesting . . . normally they would call it a 'laptop on wheels' . . . but yours looks more like a 'robot on a PC' . . . :P
I like!

How much weight can the arm handle?
Title: Re: My robot Eric
Post by: Ai-bot on August 14, 2007, 11:14:05 AM

Good job! I was wondering what is the max speed it can go.

Title: Re: My robot Eric
Post by: Ro-Bot-X on August 15, 2007, 01:04:14 AM
I will try to make some measurements and a movie today, if I get it to work in my new apartment.

Height: 34"
Arm lenght: 14" from shoulder to the tip of the fingers
                 11" from the shoulder axle to the center of the gripper
Wheel distance: 13" from touch point to touch point on the floor
Wheel diameter: 4"
Depht: 15" from the back bar to the front Sharp IR sensor
Camera height: 33" from the floor to the camera center of lenses
Max speed: 50cm/sec, min speed 5cm/sec (from ER1 kit specs); it probably is a little lower, because of added weight - the PC case is too heavy, I need to replace it with something lighter; also the battery is double in size
Turning speed: max 90 degrees/sec, min 9 degrees/sec

I'll try to run it now, back latter with results.
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 15, 2007, 09:47:15 AM
It looks like the compact flash card adapter to the IDEinterface came half way out during transportation to the new apartment. Trying to run the software corrupted some files making the system non responsive. Now I have to reinstall everything. Some files were lost because I didn't save them on my laptop. Ehhh...

Mean while, look at Eric at a convention in Romania, remotely driving around holding my friend's hand:

Title: Re: My robot Eric
Post by: HDL_CinC_Dragon on August 15, 2007, 09:55:23 AM
Why show him off moving around holding someones hand? Wouldnt that make people skeptical and say dumb things like "Thats not a robot, its just an empty shell that LOOKS like a robot and gets pulled around by people!"

You should have had him autonomously going up to dumb people and slapping them or something =) Now THAT is practical :P

But yeah, probably would have dropped jaws a little more if you had put some cans on the floor and told Eric to stack em or something =)

Good work though =)
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 15, 2007, 09:58:05 AM
I wish I'd be so advanced in programming to make Eric do all that and more... But for me is easier to put together the hardware than program the thing.
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 24, 2007, 09:50:50 AM
OK, after successfully have my friend from another city remote controll my robot through internet, I took some short movies of me remote controlling the robot to go to the refrigerator and bring a can of Pepsi back to me.

But let's see how it went...


I didn't build a hook arm that would be able to open the refrigerator door and this arm design is not capable of that, so I did it myself. But that wasn't enough...


As you can see (better say can't really see because of lack of light) the robot is not able to reach deep enough in the refrigerator to grab the can.


So I have cheated a little and put the can in it's hand...


The can is empty. The robot is barely capable to hold the filled can at horizontal arm length. The can has to stay on top of the bottom finger, otherwise it slips. I put the empty can exactly like that so you can see what I am talking about.

That's it for now, hope to get the programming going soon.
Title: Re: My robot Eric
Post by: Rebelgium on August 26, 2007, 09:03:36 AM
really cool concept, I like how Eric looks like a pro robot with the nice body...
There are still a few flaws, but I'm sure you'll be able to resolve these.
Your arm doesn't have that much power, maybe a 2 speed motor, higher refresh rate for the camera.

don't get me wrong , great work :)
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 26, 2007, 09:45:18 AM
Thanks.  :)

The thing with this robot is that I wanted to learn more about how to build a big robot, to try to solve the problems and to find out what improvements I can bring to a newer version. At the time I started this project I was a noob. So I just bought a ER1 kit (very cheap by the way), but wasn't happy with the limitations it had. S I decided to improve by building an arm and head for it. I made a bad choice picking the OOPic-R microcontroller to controll the servos and sensors and after that I made another bad choice picking Parallax Ping Ultrasonic sensors for it. OOPic is not able to fire them... And for now I live in Romania, can't buy any more parts so I have to work with whatever parts I have. And I am not good with programming, so I have a hard time trying to work this out.

However, for a next generation of butler robot(s) here are some thoughts:
- have a 2 wheel balancing robot, 12" between wheels, 12V DC gearhead motors with quadrature encoders
- have the arms mounted on the same vertical plan as the wheels and head
- have the fingers powered by air muscle (not sure about tis yet...)
- have the hand mounted on a 3 point joint, 1 fixed and 2 mobile
- have the forearm rotating around it's own "bone" close to the elbow
- have the shoulder mounted on a U joint
- have a rotating torso
- have a more powerfull mainboard (fanless) and a bigger compact flash card
- have 2 USB 2.0 or better firewire webcams for stereo vision
- have lots of IR and US range sensors for obstacle detection and mapping
- have all internal communication through USB
- use lighter batteries, one single voltage for ease of charging, somewhere in the 12V to 18V range
- use switching voltage regulators for the servos (6V) and electronics (5V)
- use one microcontroller for driving and obstacle avoidance
- use another microcontroller for head and arms controll
- the servo controller must have ramping capability
- have a light but strong structure build from aluminum, with plastic for decks and skin
- have the wheels air inflated, baby strollers have nice wheels, some even have a nice usable frame
- use toothed belts to transfer motion from motors to wheels
- ...

I am living the list open and I will add more things on the way. Please feel free to make suggestions.
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 26, 2007, 10:45:50 AM
The servos I have used for the arm are:

shoulder rotation: Hitech HS-805BB, 343 oz/in @ 6V, 0.14 sec
shoulder pan:      GWS S03T 2BB, 111 oz/in @ 6V, 0.27 sec
elbow pan:         GWS S03T 2BB, 111 oz/in @ 6V, 0.27 sec
wrist tilt:            Futaba S3004, 57 oz/in @ 6V, 0.19 sec   (not yet mounted...)
wrist rotation:     Futaba S3004, 57 oz/in @ 6V, 0.19 sec
gripper:             GWS S03N 2BB, 56 oz/in @ 6V, 0.18 sec

pan:     Futaba S3004, 57 oz/in @ 6V, 0.19 sec
tilt:      Futaba S3004, 57 oz/in @ 6V, 0.19 sec

I should have used smaller servos for the gripper and wrist rotation.
Title: Re: My robot Eric
Post by: Admin on August 27, 2007, 02:16:53 PM
use toothed belts to transfer motion from motors to wheels
timing belts ;D

hehe, dont worry, my first robot was made from a long list of bad decisions, too . . .

For the arm servos . . . I guessed your arm would fail in the beginning because of torque issues :P

Consider these for a new robot shoulder:

Cant remember if I gave you these links already or not, but this should help you calculate a robot arm that is strong enough:
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 28, 2007, 10:08:21 AM
Thanks Admin, I have seen all the links, but I allready had the thing built. I can't buy any more stuff untill I will get to Canada next spring. So for the moment I will work with what I have. I think I have a lot of robotic stuff that no Romanian has. That is because I have bought all of it when I was in the States.

I am definately considering using servo power gearboxes like those from Servocity for the arms. That is because the arm does not need speed, but power. Same for the torso. I am still considering having the robot with an extendable torso, so that it would be able to short itself (or bend) to pick up things from the floor and then elongate to the regular height so it can pick things up from the table or countertop.

The servos that I have used were bought at different times, the only consideration being the price (I got the cheapest I could find at the time). Some of them were on sale, some were bought from ebay, as a 4 pack. I still have 3 or 4, but one has a broken tooth. Same with the giant servos, I bought the cheapest that would give me lots of torque. At the time, they were pretty powerfull, and there were no power gearboxes available. Thechnology advances... And at the time, I didn't know about AVR micros and there was no Roborealm. So I bought what I could. The bad part was that I didn't know how to take full advantage of what I have bought. I still don't, but I'm getting there. (I hope...)

I invite people that are working on similar projects (like the butler robot) to describe what they are doing, maybe we can get new ideas. That is why I have described my robot here. I will be glad to answer any questions about it.

Thanks, Gabriel (Ro-Bot-X)
Title: Re: My robot Eric
Post by: airman00 on August 30, 2007, 06:33:26 AM
I am about to purchase sensors for my butler robot and was wondering how well the three IR sensors worked. I was thinking of doing a similar setup in front. Does your robot successfully navigate your home with ONLY the IR sensors??

As for the refrigerator problem, I overcame that by installing a mini-fridge on the robot itself. Then an arm and another gripper (both under construction) unscrew the bottlecap and pour the drink into a cup. I will either use pressure sensors or timers to determine how long to pour.

I promise that I will post ALL the details of my robot as well as photos and videos once the arm and sensors are installed.
Title: Re: My robot Eric
Post by: Admin on August 30, 2007, 07:06:43 AM
As for the refrigerator problem, I overcame that by installing a mini-fridge on the robot itself.
This I gotta see!!!! :o
Title: Re: My robot Eric
Post by: Ro-Bot-X on August 30, 2007, 09:46:07 AM
Does your robot successfully navigate your home with ONLY the IR sensors??

Well, I don't know. I have connected the 3 sensors in the front and one sensor in the back to the analog ports of the RCM (Robot Controll Module) of ER1. Unfortunately, the readings are not reliable, they jump up and downd regardless of presence of an object in the way or not. I am planing of using the digital ports (like a paralel port) to interface with a ATMega32. This one will read all sensors when polled from the paralel interface. It will read 4 Ultrasonic sensors (3 in the front plus one on the head), 4 IR Sharp sensors, one PIR sensor, a Compass sensor (on the I2C interface), plus what ever other sensors I will add later. I hope this weekend I can get the interface board ready. Tests will be done next weekend, because next week I will travel a lot.
Title: Re: My robot Eric
Post by: Ro-Bot-X on September 01, 2007, 09:41:08 AM
Well guys, I have seen the robot of my dreams! This is how He looks like:


I realise that I will probably not build it like this, but the result should be somwhere near it...
Title: Re: My robot Eric
Post by: airman00 on September 03, 2007, 07:47:11 PM
Cool Robot!
Title: Re: My robot Eric
Post by: airman00 on September 03, 2007, 07:52:18 PM
It even uses stereo vision cameras....