Bioloid Gripper

**JonHylands** · 07-24-2007

I have designed and built a gripper for the Bioloid humanoid robot kit. The frame parts of the gripper are "printed" from a CAD model using an ABS 3D printer. It uses a GM-14a motor for wrist rotation, and a Firgelli linear actuator for the gripper. Control is via a custom ATmega168-based PCB. The gripper , when plugged in to the Bioloid, becomes just another device on the serial bus, and can be controlled in the same manner as a regular servo.

Some blog entries:

http://www.huv.com/blog/2007/05/gripper-moving.html
http://www.huv.com/blog/2007/05/grippers-version-2.html

And finally, a picture of the robot, with two grippers installed:

- Jon

**Alex** · 07-25-2007

Those grippers look like their perfect size to grab me a bottle of beer, mmmm

Great job Jon, thanks for the entry!

**Dave** · 07-31-2007

Very cool. I have questions, if you don't mind divulging a few details:

What kind of touch sensor are you using in the gripper?
Is all of the motor control, sensor monitoring, encoder monitoring, and communication handled by the atmega?
What kind of feedback, if any, gets returned to the main controller?

**JonHylands** · 08-01-2007

Originally Posted by Dave

Very cool. I have questions, if you don't mind divulging a few details:

What kind of touch sensor are you using in the gripper?
Is all of the motor control, sensor monitoring, encoder monitoring, and communication handled by the atmega?
What kind of feedback, if any, gets returned to the main controller?

The touch sensor can be found here...

Yes, all the control and sensor monitoring is handled by the ATmega168.

The way Bioloid devices work, they maintain a control table internally with sensor values, and control values. The control values are writable, and there are bus commands to read from and write to locations in the control table.

So, its basically a polled system.

- Jon

**asbrandsson** · 08-28-2007

Hello,

I have been thinking about buying a bioloid kit or a Robonova kit- I like that you can get a lot of extra stuff for the Robonova including grippers. Is this set of Grippers going to be available for commercial sale?

Asbrandsson

**JonHylands** · 08-29-2007

No, I doubt I will ever build a product from these grippers - the linear actuators are pretty expensive, and the wiring is a little too exposed for a commercial product.

I have a few other devices available for the Bioloid - see http://www.huvrobotics.com

- Jon

**Alex** · 08-29-2007

Jon, do you have any plans on developing additional add-on components for sale for the Bioloid system?

Asbrandsson, sure, there may not be too many add-on products as of yet, but the Bioloid system uses an open serial communication bus, which means that anyone willing to learn can develop their own add-ons. You can connect up to 255 devices to a single line!

There are also companies like Crustcrawler that are doing some really incredible things with the AX-12 servos. They've changed over most (if not all) of their Robots to using the AX-12 servos. We'll be carrying them soon, so keep an eye out

It's also only a matter of time till someone develops a breakout board to plug into the Bioloid system that will allow it to use Phidget analog sensors and other standard 5V analog sensors which will open up a whole world of possibilities. I'm not the expert in Zigbee so I don't know the limitations of Zigbee (Jon or Dave, care to enlighten us?), but think about it... Zigbee enabled CM-5 modules with these sensors connected spread around rooms. Then, you have a dozen or so Bioloid Robots walking around these rooms, which are all connected to the Zigbee "network". Sensor data changes and the Bioloid Robots get informed, which then prompts them to go check out what happened. Again, not an expert in Zigbee, but you should still get the idea.

**JonHylands** · 08-30-2007

Originally Posted by Alex

Jon, do you have any plans on developing additional add-on components for sale for the Bioloid system?

...

It's also only a matter of time till someone develops a breakout board to plug into the Bioloid system that will allow it to use Phidget analog sensors and other standard 5V analog sensors which will open up a whole world of possibilities.

I have a simple I/O board which I am about to "productize", which basically means getting some production boards made.

Here's a picture.

The micro-controller is an ATmega168, running the same basic Bioloid device software my other devices run.

The board connectors are as follows:

The six 3-pin sockets at the top are analog inputs. Each 3-pin socket has analog in, power, and ground.

The four 3-pin sockets in the lower right are digital I/O's. Each 3-pin socket has digital in/out, power, and ground.

The five-pin connector immediately to the left of the Digital I/O's is the motor drive, which has two PWM pins, two direction pins, and ground. It is set up for doing sign magnitude PWM.

The six-pin header in the upper right is of course the programming header. There are two Bioloid bus connectors, and a jumper for the Tx/Rx pins (in case you want to turn this into a receive-only board. The LED is hooked up like a normal Bioloid LED.

The voltage regulator is at the top left, and will be available in either 3.3 volt or 5 volt, depending on what sensors you want to hook up.

The control table looks like this (subject to change):

00 - Model # (2 bytes)
02 - Firmware Version
03 - ID
04 - Baud Rate
05 - Return Delay Time
16 - Status Return Level
25 - LED
26 - Analog Input 0 (2 bytes)
28 - Analog Input 1 (2 bytes)
30 - Analog Input 2 (2 bytes)
32 - Analog Input 3 (2 bytes)
34 - Analog Input 4 (2 bytes)
36 - Analog Input 5 (2 bytes)
38 - Digital 0 Direction
39 - Digital 0 Input/Output
40 - Digital 1 Direction
41 - Digital 1 Input/Output
42 - Digital 2 Direction
43 - Digital 2 Input/Output
44 - Digital 3 Direction
45 - Digital 3 Input/Output
46 - Motor A Speed (2 bytes)
48 - Motor B Speed (2 bytes)

One change I plan on making is moving the digital I/O direction entries to the EEPROM side of the control table, so they are persistent.

Since the Phidget standard for 3-pin analog seems to be data/power/ground, you should be able to plug them directly into the analog headers on this board...

- Jon