Balancing robot nightmare

I got this idea i could build a dolly cart (I think thats what its called in English) that balances itself. This way the delivery man can fill in a form, ring the door bell etc. and not have to hold the dolly.

It seems this was harder than i expected so I wanted to build a balance robot first. Now 2 types of servo's a arduino mega, uno , motor shield, proto shield and lots of hours later I think its the IMU (mpu 6050) thats not working. My question is: What is a good imu for a balance robot? I would like to keep the price below 50$ and it should be simple to implement into the project. (I'm just starting with arduino)

The following might be of use for background information,

http://www.geology.smu.edu/dpa-www/robo/nbot/index.html

You're probably going to need some very fast, high-torque motors. Servos probably
won't be fast enough for the drive.

Thanks for the reply.

oric_dan(333):
The following might be of use for backgournd information,

nBot, a two wheel balancing robot

This balance robot uses ultrasonic sonar sensors, and IR distance detectors (I would like to build it with a IMU)

oric_dan(333):
You're probably going to need some very fast, high-torque motors. Servos probably
won't be fast enough for the drive.

My first step is to create a working balance robot. If I get that to work I can than build a self balancing dolly cart. The amount of information availible on arduino and balancing robots is amazing. My problem is finding a detailed step by step tutorial and then buy the IMU used in the tutorial.

Most tutorials I have read are not very detailed. There are some, even on the arduino forum (like the balancing robot for dummies) but after reading pages and pages of info it seems the more I read the less I understand it.

Read down to where it says:

The ball-bearing pivot and angle sensor were replaced by a piezo-electric gyroscope and ADXL202 accelerometer mounted just above the motor deck. Those sensors were eventually replaced by a commerical inclinometer, the FAS-G from MicroStrain, also consisting of an ADXL202 accelerometer and a rate gyro, similar to the boards and kits available from rotomotion. This rear view shows the complete stack.
.............
The gyroscope and accelerometer are combined with complementary filters to provide an inertial reference sensor. The ADXL202 accelerometer provides accurate static tilt information, when the robot is not accelerating. The gyroscope can be integrated to provide accurate dynamic tilt information, but the integration tends to drift over time. Combining the two sensors provides a robust inertial measurement. The FAS-G IMU implements a "Weiner" filter to combine the two sensors into a single measurement. The sourceforge autopilot project. and the boards available from rotomotion.com use a "Kalman" filter. Some really good information on inertial measurement units is available from the sourceforge autopilot project.

Do you have any experience in programming or robotics?

Can’t say I’d recommend this as your “Hello World” into Mechatronics.

BlueBill:
Do you have any experience in programming or robotics?

No, just blink a light and thats about it.. I thought it was just a step by step thing if i had the parts. It seems i have to do some smaller projects before I can start building a balance robot.

BlueBill:
Can't say I'd recommend this as your "Hello World" into Mechatronics.

:~ What do you mean?

janh:

BlueBill:
Can't say I'd recommend this as your "Hello World" into Mechatronics.

:~ What do you mean?

He means it's difficult. Among computer programmers it's become traditional that your first test program just displays the message "Hello World!", and this has become synonymous with a very simple program created as a learning aid.

Ok so this means building a balance robot is the "hello world" of arduino??

Thanks for the imput, I will try some other projects first.

He means balancing robots are definitely not a "hello world" introduction.

If you want to see it done with chutzpah though look at this

Yes, follow the "learning curve", each step involves more complex issues.

  1. learn to program Arduino.
  2. build and program at least 1 simple and basic robot, preferably one that
    uses differential steering, and motors or modified servo drive.
  3. learn the maths involved with programming the IMU on the n-Bot site.
  4. build and program your balancing robot.
  5. post to the Robotics section of the forum.