RFLEX plugin - Revision history

Jca: /* rFlex protocold */

2013-09-16T16:12:40Z

rFlex protocold

← Older revision		Revision as of 18:12, 16 September 2013
Line 137:		Line 137:
	CHECKSUM \| 1 byte \| xor of all bytes from PORT to end of DATA		CHECKSUM \| 1 byte \| xor of all bytes from PORT to end of DATA
	PKT_ETX \| 2 bytes \| 0x1b 0x03		PKT_ETX \| 2 bytes \| 0x1b 0x03


			Byte stuffing

	As communication is binary and PKT_STX and PKT_ETX needs to be unique, then if the escape character is in the data, and escape sequence is stuffed, like:		As communication is binary and PKT_STX and PKT_ETX needs to be unique, then if the escape character is in the data, and escape sequence is stuffed, like:

	~~????? not found yet~~		By code inspection in http://wurde.sourceforge.net/doxygen/a00376.html#l00473 it seems like an escape sequence of 0x1b 0x00 should be replaced by just 0x1b, and escape sequence 0x1b 0x01 should just be removed (a bit odd that it is there in the first place).

			Testing has shown that "all" packages are now received with no errors, with this interpretation if byte stuffing (jca 16 sep 2013).
			- change included in mobotware version 3.240.

Jca at 14:41, 16 September 2013

2013-09-16T14:41:07Z

Show changes

S021786 at 08:53, 28 January 2009

2009-01-28T08:53:00Z

← Older revision		Revision as of 10:53, 28 January 2009
Line 7:		Line 7:
	rFLEX provides a full interface to the robot sensors, and does somewhat of post-processing, such as odometry calculations and ultrasound processing.		rFLEX provides a full interface to the robot sensors, and does somewhat of post-processing, such as odometry calculations and ultrasound processing.

	The intension of the interface is to create a flexible platform for all iRobot research robots. As we only had the ATRV-Jr robot for testing, the rFLEX plugin is kept as universal as possible, but bumpers and ultrasound ~~senaors~~ are mapped specifically for ATRV-Jr.		The intension of the interface is to create a flexible platform for all iRobot research robots. As we only had the ATRV-Jr robot for testing, the rFLEX plugin is kept as universal as possible, but bumpers and ultrasound sensors are mapped specifically for ATRV-Jr.

	Odometry is provided in a translation / rotation axis configuration. The system outputs position, velocity, ~~accelleration~~ and torque in both axes (i.e. forward speed and rotation speed)		Odometry is provided in a translation / rotation axis configuration. The system outputs position, velocity, acceleration and torque in both axes (i.e. forward speed and rotation speed)

	== XML Configuration ==		== XML Configuration ==

	Through the RHD XML configuration, it is possible to define parameters for the plug-in		Through the [[RHD]] XML configuration, it is possible to define parameters for the plug-in

	The default configuration is seen below:		The default configuration is seen below:
Line 36:		Line 36:
	== Plug-in special features ==		== Plug-in special features ==

	Normally, it is against RHD principles to assign too much robot functionality into the plug-ins. But as a safety feature, a brake feature is coupled to the bumpers of the robot.		Normally, it is against [[RHD]] principles to assign too much robot functionality into the plug-ins. But as a safety feature, a brake feature is coupled to the bumpers of the robot.

	If the bumperbrake is enabled, the robot will enable it's brake, when bumpers is touched. The default setting is assigned in the XML configuration, but a write-variable makes it possible to en/disable the feature at runtime.		If the bumperbrake is enabled, the robot will enable it's brake, when bumpers is touched. The default setting is assigned in the XML configuration, but a write-variable makes it possible to en/disable the feature at runtime.

S021786 at 11:05, 30 September 2008

2008-09-30T11:05:07Z

← Older revision		Revision as of 13:05, 30 September 2008
Line 60:		Line 60:
	\|-		\|-
	! r		! r
	\| ~~transposition~~ \|\| [pos] \|\| Position of translation (distance)		\| transpos \|\| [pos] \|\| Position of translation (distance)
	\|-		\|-
	! r		! r
Line 72:		Line 72:
	\|-		\|-
	! r		! r
	\| ~~rotposition~~ \|\| [pos] \|\| Position of rotation (bering)		\| rotpos \|\| [pos] \|\| Position of rotation (bering)
	\|-		\|-
	! r		! r
Line 90:		Line 90:
	\|-		\|-
	! w		! w
	\| ~~transaccl~~ \|\| [accl] \|\| Max acceleration of translation (XML default used if = 0)		\| cmdtransaccl \|\| [accl] \|\| Max acceleration of translation (XML default used if = 0)
	\|-		\|-
	! w		! w
	\| ~~transtorque~~ \|\| [torque] \|\| Max torque of translation (XML default used if = 0)		\| cmdtranstorque \|\| [torque] \|\| Max torque of translation (XML default used if = 0)
	\|-		\|-
	! w		! w
	\| ~~rotvel~~ \|\| [vel] \|\| Desired velocity of rotation (command)		\| cmdrotvel \|\| [vel] \|\| Desired velocity of rotation (command)
	\|-		\|-
	! w		! w
	\| ~~rotaccl~~ \|\| [accl] \|\| Max acceleration of rotation (XML default used if = 0)		\| cmdrotaccl \|\| [accl] \|\| Max acceleration of rotation (XML default used if = 0)
	\|-		\|-
	! w		! w
	\| ~~rottorque~~ \|\| [torque] \|\| Max torque of rotation (XML default used if = 0)		\| cmdrottorque \|\| [torque] \|\| Max torque of rotation (XML default used if = 0)
	\|-		\|-
	! w		! w

S021786: rFLEX plugin description final

2008-09-29T13:54:39Z

rFLEX plugin description final

New page

As the Institute for Automation got a hand on an iRobot ATRV-Jr robot platform, we needed a plug-in to control the robot. The robot has a fully developed control framework built-in, the rFLEX, that provides odometry and sensors through a RS-232 connection.

iRobot has moved focus towards developing consumer (vacuum) and military robots, so no documentation '''at all''' is available for the robot. Fortunately, Carnegie Mellon University (CMU) has drivers for the rFLEX in their Carnegie Mellon Robot Navigation Toolkit ([http://carmen.sourceforge.net, CARMEN]). This is actually also the base for the rFLEX drivers in Player/Stage framework. About half of the code is ported from [http://carmen.sourceforge.net, CARMEN] - Thank you guys!

== The rFLEX system ==

rFLEX provides a full interface to the robot sensors, and does somewhat of post-processing, such as odometry calculations and ultrasound processing.

The intension of the interface is to create a flexible platform for all iRobot research robots. As we only had the ATRV-Jr robot for testing, the rFLEX plugin is kept as universal as possible, but bumpers and ultrasound senaors are mapped specifically for ATRV-Jr.

Odometry is provided in a translation / rotation axis configuration. The system outputs position, velocity, accelleration and torque in both axes (i.e. forward speed and rotation speed)

== XML Configuration ==

Through the RHD XML configuration, it is possible to define parameters for the plug-in

The default configuration is seen below:

<code>

<rflex enable="true" lib="librflex.so.1" critical="true">
<serial port="/dev/ttyUSB0" baudrate="115200" />
<odometry period="100000" />
<translation accel="100000" torque="30000" />
<rotation accel="100000" torque="35000" />
<bumperbrake default="true" />
</rflex>
</code>

Configuration include serial port settings and default values for accelleration and torque in both translation and rotation axes.

The odometry period sets, how often a odometry package is sampled to the serial bus. The value is in µs.

The final parameter is the bumperbrake, that is described below.

== Plug-in special features ==

Normally, it is against RHD principles to assign too much robot functionality into the plug-ins. But as a safety feature, a brake feature is coupled to the bumpers of the robot.

If the bumperbrake is enabled, the robot will enable it's brake, when bumpers is touched. The default setting is assigned in the XML configuration, but a write-variable makes it possible to en/disable the feature at runtime.
This makes the response-time as short as possible for emergency stop.

== Plug-in variables ==

Most of the plug-in functionality is described by the plug-ins it creates

{| class="wikitable"
|+ rFLEX plugin variable table
|-
! Direction     !! Variable name     !! Array contents     !! Description
|-
! r
| transvel || [vel] || Velocity of translation
|-
! r
| transaccl || [accl] || Acceleration of translation
|-
! r
| transtorque || [torque] || Torque of translation
|-
! r
| transposition || [pos] || Position of translation (distance)
|-
! r
| rotvel || [vel] || Velocity of rotation
|-
! r
| rotaccl || [accl] || Acceleration of rotation
|-
! r
| rottorque || [torque] || Torque of rotation
|-
! r
| rotposition || [pos] || Position of rotation (bering)
|-
! r
| sonar || [s0]..[s16] || Measurements of sonars (mapped 0-16, as on ATRV-Jr)
|-
! r
| bumper || [front][rear] || Status of ARTV-Jr bumpers
|-
! r
| brake || [brake] || Status of robot brake (updated at 1Hz)
|-
! r
| battvoltage || [batt] || Raw mesurement of battery voltage (needs calibration and updated at 1Hz)
|-
! w
| cmdtransvel || [vel] || Desired velocity of translation (command)
|-
! w
| transaccl || [accl] || Max acceleration of translation (XML default used if = 0)
|-
! w
| transtorque || [torque] || Max torque of translation (XML default used if = 0)
|-
! w
| rotvel || [vel] || Desired velocity of rotation (command)
|-
! w
| rotaccl || [accl] || Max acceleration of rotation (XML default used if = 0)
|-
! w
| rottorque || [torque] || Max torque of rotation (XML default used if = 0)
|-
! w
| usesonar || [enable] || Enable / disable ultrasound sonars (default off)
|-
! w
| cmdbrake || [brake] || Enable / disable robot brake (default off)
|-
! w
| bumperbrake || [enable] || Enable / disable bumperbrake (overrides default)
|}

Using these variables, it is possible to control all functions on the ATRV-Jr robot... Enjoy