legs . . . .

Hello im new here, The robot should have legs. Integrate a gyroscope to creat the gravity center of the robot.

Mats's picture

Hi

Welcome FML_CPU.

Yes, That's definitley on the TODO list :-)

To make that happen we are working on an i2c interface that can be used to access many different types of hardware. One of the devices drivers that I'm working on now is the MPU6050. It contains a 3-axis accelerometer and a 3-axis gyro. 

It a very small and cheap device that can be found on Ebay for < 2EUR so I'm planning to use it in many places. For example in the hand to be able to balance a glass or a plate. The same device can be used in the body to know the position of the upper body. 

/Mats

Alessandruino's picture

Hey Mats, Did you happen to

Hey Mats,
Did you happen to solve the problem of multiple mpu6050? I wanted to use more on my arm to control inmoov arm but seems like you Can select only between 2 i2c adresses..

Alessandro

Mats's picture

Multiple MPU6050 sensors

Hi Alessandruino

There is a post here about how to connect multiple MPU6050 to the same i2c bus, but I haven't tried it.

It requires one extra pin for each MPU6050. 

http://playground.arduino.cc/Main/MPU-6050

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A second alternative is to have mutiple i2c lines by using more Arduinos.

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A third alternative is to use a i2c multiplexer like this: 

https://learn.adafruit.com/adafruit-tca9548a-1-to-8-i2c-multiplexer-brea...

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I like your idea, because with an MPU-6050 in each part of the arm, we could know their positions with very good precision. 

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The first and second alternative will be supported soon. I just need to implement three messages in Arduino and MRLComm to make it work. 

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I think it's possible to create a i2c multiplexer service to support alternative 1 and 3. 

What alternative do you prefer ?

/Mats

FML_CPU's picture

artificial musclu

What do you think about artificial muscle activatec whit air ? like this one

 

http://wyss.harvard.edu/staticfiles/newsroom/pressreleases/Muscle-Actuat...

 

and for the gyroscope i think something more simple, like a magnetic gyro, no need sensor, juste a magnetic mass, wen the power is ON the mass turn very fast on iself and stabelise the entire robot body. . . . i dont have a gif for this idea 

well im still verry new on this project.

i have a lot of idea for this very interesting project.

 

Frédéric Mercier-Leboeuf

Mats's picture

Frédéric

Hi Frédéric

For some reason I couldn't open your link (404).

I have seen many types of air muscles and they all have some advantages and disadvantages. So far, nobody ( that I know about ) has experimented with air muscles in the InMoov robot. With the 3D printing technology, and the ability to print different materials at the same time, I think that many new things will evolve. I love new ideas, that's what makes the robotic projects so exciting. There is challenges for everyone, independant on what level you are at.

I understand the gyro idea. I don't think it has to be magnetic to work. 

/Mats

Mats's picture

i2c multiplexer

Hi

I ordered a TCA9548A yesterday, that I will use to experiment with. I hope I will receive it tomorrow or on Friday.

https://learn.adafruit.com/adafruit-tca9548a-1-to-8-i2c-multiplexer-brea...

The goal is to have a i2cMultiplexer service that can be used in three different modes:

1. Using the tca9548a, extending any i2c bus with 8 more i2c buses. The multiplexer will handle the logic needed to switch between the different buses. Using this method you can address 9 different devices that has the same address. 1 on the main i2c bus and 1 on each additional i2c bus. Since most devices can have at least 2 different addresses, this would enable 18 devices of the same type without conflicts. I think that should be enough in most cases. If not, then it's also possible to have up to 8 tca9548a's on the same i2c bus. 

2 Using GPIO pins on the RasPi to enable/disable i2cdevices. The multiplexer will handle the logic needed to enable/disable i2c devices. The number of i2c devices will be limited by the number of pins that you can dedicate for i2c devices. 24 will be maximum number since the i2c interface uses 2 pins.

3. Using pins on the Arduino to enable/disable i2cdevices. The multiplexer will handle the logic needed to enable/disable i2c devices. The number of i2c devices will be limited by the number of pins that you can dedicate for i2c devices. 18 will be maximum number on the UNO since the i2c interface uses 2 pins. Probably 52 on the Mega. 

/Mats

 

GroG's picture

I think Fredric meant to post

I think Fredric meant to post this image

Here's a potential canidate (specifically the valve)

http://www.instructables.com/id/Pneumatic-Muscles/ 

 

 

 

 

 

And finally probably the least expensive pneumatic valves I have seen 

http://www.aliexpress.com/store/product/Airtac-Type-5-Way-2-Position-Con...

 

Mats's picture

Other types of pneymatic actuators

Hi 

The first minutes of this video shows a different type of pneumatic actuator that I find interesting. 

 

 

/Mats

 

FML_CPU's picture

It was actualy the firts one

It was actualy the firts one whit the bonne arms.

 

A new idea came on my mind for the air muscle, if we can print soft plastic, we will be able to print a muscular fiber structure in soft plastic, then cover them whit a thin layer of soft plastic.

 

Whith this air mecanism, the joint whill no need motors enymore, juste a systeme of tubing that pass throug the soft printed muscular systeme.

 

Im not building the robot actualy, i juste want to share my idea, and maibe later create the robot.

Im very pasionat by this project!