HAL
To get more information about the Hardware Abstraction Layer and how it works, please have a look into the HAL described on the eeros wiki.
EEROS for the Beagle Bone Blue is using the robotis_cape_library. You'll find the wrapper and its functions in the bbblue-eeros folder.
Configure the motors
If you want to run a motor with EEROS you need to define a Peripheral Output with the respective “signalId” used in the HAL-Configuration file. As you can see in the HAL-Configuration file for the Delta roboter in “subdevice2” the type for the motors is set to “AnalogOut”. In this subdevice section the 4 motors are configured to match the functions of the robotics_cape_library. In the EEROS application for the Delta roboter you can set a motor voltage of -8.0V to 8.0V. The HAL gets this values and wraps it to match the values of the robotics_cape_library which then runs the motors with the desired voltage.
Configure the encoders
The Delta roboter has two different motors with different encoders and gears. You'll find the datasheets of the two types here.
Calculate the Axis Motor
The Axis Motor is equipped with gear with gear ration 76:1 and with the encoder ieh2-4096, which provides 4096 lines per revolution ( =16384 counts per revolution). So for one full turn on the gear axis, the encoder sends 16384*76 = 1245184 counts. This is the input value for the HAL.
In the EEROS application we don't want to calculate everytime the respective radian value from this counts, so we do this in the HAL. To do that, we need to add some “blocks”.
Start with the gear:
one full turn on the gear axis (=2*PI) equals to 76 turns of the motor axis. Next up, for one revolution of the motor axis, the encoder sends 4096 lines. So if we turn the gear axis for one revolution, the motor axis turns 76 times and the encoder sends 76*4096 = 311296 lines. The last block is the FQD. It converts the lines of the encoder into single counts. One line equals to 4 counts.
HAL-Configuration file for the Delta roboter
{
"device0": {
"library": "libbbblueeeros.so",
"devHandle": "dummy",
"subdevice0": {
"type": "DigOut",
"channel0": {
"signalId": "onBoardGreen"
},
"channel1": {
"signalId": "ledBlue"
},
"channel49": {
"signalId": "ledRed"
},
"channel116": {
"signalId": "onBoardRed"
},
"channel98": {
"signalId": "emag"
}
},
"subdevice1": {
"type": "DigIn",
"channel0": {
"signalId": "buttonMode"
},
"channel1": {
"signalId": "buttonPause"
},
"channel97": {
"signalId": "buttonBlue"
},
"channel57": {
"signalId": "buttonRed"
},
"channel113": {
"signalId": "buttonGreen"
}
},
"subdevice2": {
"type": "AnalogOut",
"channel1": {
"signalId": "motor1",
"scale": [ { "id" : "dac",
"minIn": -1.0, "maxIn": 1.0,
"minOut": -8.0, "maxOut": 8.0 }
],
"range": [ { "id" : "dac",
"minIn": -0.75, "maxIn": 0.75,
"minOut": -6.0, "maxOut": 6.0 }
],
"unit": "V"
},
"channel2": {
"signalId": "motor2",
"scale": [ { "id" : "dac",
"minIn": -1.0, "maxIn": 1.0,
"minOut": -8.0, "maxOut": 8.0 }
],
"range": [ { "id" : "dac",
"minIn": -0.75, "maxIn": 0.75,
"minOut": -6.0, "maxOut": 6.0 }
],
"unit": "V"
},
"channel3": {
"signalId": "motor3",
"scale": [ { "id" : "dac",
"minIn": -1.0, "maxIn": 1.0,
"minOut": -8.0, "maxOut": 8.0 }
],
"range": [ { "id" : "dac",
"minIn": -0.75, "maxIn": 0.75,
"minOut": -6.0, "maxOut": 6.0 }
],
"unit": "V"
},
"channel4": {
"signalId": "motor4",
"scale": [ { "id" : "dac",
"minIn": -1.0, "maxIn": 1.0,
"minOut": -6.0, "maxOut": 6.0 }
],
"range": [ { "id" : "dac",
"minIn": -1, "maxIn": 1,
"minOut": -6.0, "maxOut": 6.0 }
],
"unit": "V"
}
},
"subdevice3": {
"type": "Fqd",
"channel1": {
"signalId": "enc1",
"scale": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"range": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"unit": "rad"
},
"channel2": {
"signalId": "enc2",
"scale": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"range": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"unit": "rad"
},
"channel3": {
"signalId": "enc3",
"scale": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"range": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 477.522083346 },
{ "id" : "enc",
"minIn": 0, "maxIn": 477.522083346,
"minOut": 0, "maxOut": 311296},
{ "id" : "fqd",
"minIn": 0, "maxIn": 311296,
"minOut": 0, "maxOut": 1245184}
],
"unit": "rad"
},
"channel4": {
"signalId": "enc4",
"scale": [ { "id" : "gear",
"minIn": 0, "maxIn": 5.8,
"minOut": 0, "maxOut": 670.206432766 },
{ "id" : "enc",
"minIn": 0, "maxIn": 753.982236862,
"minOut": 0, "maxOut": 30720},
{ "id" : "fqd",
"minIn": 0, "maxIn": 30720,
"minOut": 0, "maxOut": 122880}
],
"range": [ { "id" : "gear",
"minIn": 0, "maxIn": 6.283185307,
"minOut": 0, "maxOut": 753.982236862 },
{ "id" : "enc",
"minIn": 0, "maxIn": 753.982236862,
"minOut": 0, "maxOut": 30720},
{ "id" : "fqd",
"minIn": 0, "maxIn": 30720,
"minOut": 0, "maxOut": 122880}
],
"unit": "rad"
}
}
}
}