rflex

RWI mobile robots. More...

RWI mobile robots.

The rflex driver is used to control RWI robots by directly communicating with RFLEX onboard the robot (i.e., Mobility is bypassed). To date, these drivers have been tested on an ATRV-Jr, but they should work with other RFLEX-controlled robots: you will have to determine some parameters to set in the config file, however.

As of March 2003 these drivers have been modified to support the b21r robot, Currently additional support has been added for the power interface and bumper interface. For the pan tilt unit on the b21r please refer to the ptu46 driver.

Compile-time dependencies

• none

Provides

The rflex driver provides the following device interfaces, some of them named:

• position2d : This interface returns odometry data, and accepts velocity commands.
• "sonar" sonar : Range data from the sonar array
• "sonar2" sonar : Range data from the second sonar array
• ir
• bumper
• power
• aio
• dio

Supported configuration requests

• The position2d interface supports:
  • PLAYER_POSITION2D_REQ_SET_ODOM
  • PLAYER_POSITION2D_REQ_MOTOR_POWER
  • PLAYER_POSITION2D_REQ_VELOCITY_MODE
  • PLAYER_POSITION2D_REQ_RESET_ODOM
  • PLAYER_POSITION2D_REQ_GET_GEOM
• The ir interface supports:
  • PLAYER_IR_REQ_POWER
  • PLAYER_IR_REQ_POSE
• The "sonar" sonar interface supports:
  • PLAYER_SONAR_REQ_POWER
  • PLAYER_SONAR_REQ_GET_GEOM
• The "sonar2" sonar interface supports:
  • PLAYER_SONAR_REQ_POWER
  • PLAYER_SONAR_REQ_GET_GEOM
• The bumper interface supports:
  • PLAYER_BUMPER_REQ_GET_GEOM

Configuration file options

• port (string)
  • Default: "/dev/ttyR0"
  • Serial port used to communicate with the robot.
• m_length (float)
  • Default: 0.5
  • Length of the robot in meters
• m_width (float)
  • Default: 0.5
  • Width of the robot in meters
• odo_distance_conversion (float)
  • Default: 0
  • Odometry conversion. See Note 1.
• odo_angle_conversion (float)
  • Default: 0
  • Odometry conversion. See Note 2.
• default_trans_acceleration (float)
  • Default: 0.1
  • Set translational acceleration, in m.
• default_rot_acceleration (float)
  • Default: 0.1
  • Set rotational acceleration, in radians.
• rflex_joystick (integer)
  • Default: 0
  • Enables joystick control via the rflex controller
• rflex_joy_pos_ratio (float)
  • Default: 0
  • Joystick to movement conversion ratio
• rflex_joy_ang_ratio (float)
  • Default: 0
  • Joystick to movement conversion ratio
• range_distance_conversion (float)
  • Default: 1476
  • Sonar range conversion factor. See Note 7.
• max_num_sonars (integer)
  • Default: 64
  • See Note 4
• num_sonars (integer)
  • Default: 24
  • See Note 4
• sonar_age (integer)
  • Default: 1
  • Prefiltering parameter. See Note 3.
• num_sonar_banks (integer)
  • Default: 8
  • See Note 4
• num_sonars_possible_per_bank (integer)
  • Default: 16
  • See Note 4
• num_sonars_in_bank (integer tuple)
  • Default: [ 8 8 8 ... ]
  • See Note 4
• sonar_echo_delay (integer)
  • Default: 3000
  • Sonar configuration parameters
• sonar_ping_delay (integer)
  • Default: 0
  • Sonar configuration parameters
• sonar_set_delay (integer)
  • Default: 0
  • Sonar configuration parameters
• mrad_sonar_poses (tuple float)
  • Default: [ 0 0 0 ... ]
  • Sonar positions and directions. See Note 6.
• sonar_2nd_bank_start (integer)
  • Default: 0
  • Address of the second sonar bank (lower bank on the b21r)
• pose_count (integer)
  • Default: 8
  • Total Number of IR sensors
• rflex_base_bank (integer)
  • Default: 0
  • Base IR Bank
• rflex_bank_count (integer)
  • Default: 0
  • Number of banks in use
• ir_min_range (float)
  • Default: 0.100
  • Min range of ir sensors (m) (Any range below this is returned as 0)
• ir_max_range (float)
  • Default: 0.800
  • Max range of ir sensors (m) (Any range above this is returned as max)
• rflex_banks (float tuple)
  • Default: [ 0 0 0 ... ]
  • Number of IR sensors in each bank
• poses (float tuple)
  • Default: [ 0 0 0 ... ]
  • x,y,theta of IR sensors (m, m, deg)
• rflex_ir_calib (float tuple)
  • Default: [ 1 1 ... ]
  • IR Calibration data (see Note 8)
• bumper_count (integer)
  • Default: 0
  • Number of bumper panels
• bumper_def (float tuple)
  • Default: [ 0 0 0 0 0 ... ]
  • x,y,theta,length,radius (m,m,deg,m,m) for each bumper
• rflex_bumper_address (integer)
  • Default: 0x40
  • The base address of first bumper in the DIO address range
• rflex_bumper_style (string)
  • Default: "addr"
  • Bumpers can be defined either by addresses or a bit mask
• rflex_power_offset (float)
  • Default: 0
  • The calibration constant for the power calculation in volts

Notes

1. Since the units used by the Rflex for odometry appear to be completely arbitrary, this coefficient is needed to convert to meters: m = (rflex units) / (odo_distance_conversion). These arbitrary units also seem to be different on each robot model. I'm afraid you'll have to determine your robot's conversion factor by driving a known distance and observing the output of the RFlex.
2. Conversion coefficient for rotation odometry: see odo_distance_conversion. Note that heading is re-calculated by the Player driver since the RFlex is not very accurate in this respect. See also Note 1.
3. Used for prefiltering: the standard Polaroid sensors never return values that are closer than the closest obstacle, thus we can buffer locally looking for the closest reading in the last "sonar_age" readings. Since the servo tick here is quite small, you can still get pretty recent data in the client.
4. These values are all used for remapping the sonars from Rflex indexing to player indexing. Individual sonars are enumerated 0-15 on each board, but at least on my robots each only has between 5 and 8 sonar actually attached. Thus we need to remap all of these indexes to get a contiguous array of N sonars for Player.
   • max_num_sonars is the maximum enumeration value+1 of all sonar meaning if we have 4 sonar boards this number is 64.
   • num_sonars is the number of physical sonar sensors - meaning the number of ranges that will be returned by Player. - num_sonar_banks is the number of sonar boards you have.
   • num_sonars_possible_per_bank is probobly 16 for all robots, but I included it here just in case. this is the number of sonar that can be attached to each sonar board, meaning the maximum enumeration value mapped to each board. - num_sonars_in_bank is the nubmer of physical sonar attached to each board in order - you'll notice on each the sonar board a set of dip switches, these switches configure the enumeration of the boards (ours are 0-3)
5. The first RFlex device (position, sonar or power) in the config file must include this option, and only the first device's value will be used.
6. This is about the ugliest way possible of telling Player where each sonar is mounted. Include in the string groups of three values: "x1 y1 th1 x2 y2 th2 x3 y3 th3 ...". x and y are m and theta is radians, in Player's robot coordinate system.
7. Used to convert between arbitrary sonar units to millimeters: m = sonar units / range_distance_conversion.
8. Calibration is in the form Range = a*Voltage^b and stored in the tuple as [a1 b1 a2 b2 ...] etc for each ir sensor.

Example

driver
(
  name "rflex"
  provides ["position2d:1" "bumper:0" "sonar::sonar:0" "sonar2::sonar:1" "power:0" "ir:0"]

  rflex_serial_port     "/dev/ttyR0"
  m_length      0.5
  m_width       0.5
  odo_distance_conversion   103000
  odo_angle_conversion    35000
  default_trans_acceleration  0.5
  default_rot_acceleration    0.017
  rflex_joystick      1
  rflex_joy_pos_ratio   6
  rflex_joy_ang_ratio   -0.01


  bumper_count    14
  bumper_def    [   -216.506351 125.000000 -210.000000 261.799388 250.000000 -0.000000 250.000000 -270.000000 261.799388 250.000000 216.506351 125.000000 -330.000000 261.799388 250.000000 216.506351 -125.000000 -390.000000 261.799388 250.000000 0.000000 -250.000000 -450.000000 261.799388 250.000000 -216.506351 -125.000000 -510.000000 261.799388 250.000000 -240.208678 -99.497692 -157.500000 204.203522 260.000000 -240.208678 99.497692 -202.500000 204.203522 260.000000 -99.497692 240.208678 -247.500000 204.203522 260.000000 99.497692 240.208678 -292.500000 204.203522 260.000000 240.208678 99.497692 -337.500000 204.203522 260.000000 240.208678 -99.497692 -382.500000 204.203522 260.000000 99.497692 -240.208678 -427.500000 204.203522 260.000000 -99.497692 -240.208678 -472.500000 204.203522 260.000000 ]
  rflex_bumper_address  64 # 0x40

  range_distance_conversion   1.476
  sonar_age       1
  sonar_echo_delay    30000
  sonar_ping_delay    0
  sonar_set_delay     0
  max_num_sonars      224
  num_sonars        48
  num_sonar_banks     14
  num_sonars_possible_per_bank  16
  num_sonars_in_bank    [4 4 4 4 4 4 3 3 3 3 3 3 3 3]
  # theta (rads), x, y (m) in robot coordinates (x is forward)
  mrad_sonar_poses  [     3.01069  -0.24786122    0.03263155     2.74889  -0.23096988    0.09567086     2.48709  -0.19833834   0.15219036     2.22529  -0.15219036   0.19833834     1.96350   -0.09567086   0.23096988     1.70170   -0.03263155   0.24786122     1.43990    0.03263155   0.24786122     1.17810    0.09567086   0.23096988     0.91630   0.15219036   0.19833834     0.65450   0.19833834   0.15219036     0.39270   0.23096988    0.09567086     0.13090   0.24786122    0.03263155    -0.13090   0.24786122   -0.03263155    -0.39270   0.23096988   -0.09567086    -0.65450   0.19833834  -0.15219036    -0.91630   0.15219036  -0.19833834    -1.17810    0.09567086  -0.23096988    -1.43990    0.03263155  -0.24786122    -1.70170   -0.03263155  -0.24786122    -1.96350   -0.09567086  -0.23096988    -2.22529  -0.15219036  -0.19833834    -2.48709  -0.19833834  -0.15219036    -2.74889  -0.23096988   -0.09567086    -3.01069  -0.24786122   -0.03263155       4.18879  -0.13000000  -0.22516660     3.92699  -0.18384776  -0.18384776     3.66519  -0.22516660  -0.13000000     3.40339  -0.25114071   -0.06729295     3.14159  -0.26000000     0.00000     2.87979  -0.25114071    0.06729295     2.61799  -0.22516660   0.13000000     2.35619  -0.18384776   0.18384776     2.09440  -0.13000000   0.22516660     1.83260   -0.06729295   0.25114071     1.57080     0.00000   0.26000000     1.30900    0.06729295   0.25114071     1.04720   0.13000000   0.22516660     0.78540   0.18384776   0.18384776     0.52360   0.22516660   0.13000000     0.26180   0.25114071    0.06729295     0.00000   0.26000000     0.00000    -0.26180   0.25114071   -0.06729295    -0.52360   0.22516660  -0.13000000    -0.78540   0.18384776  -0.18384776    -1.04720   0.13000000  -0.22516660    -1.30900    0.06729295  -0.25114071    -1.57080     0.00000  -0.26000000    -1.83260   -0.06729295  -0.25114071    -2.09440  -0.13000000  -0.22516660    -2.35619  -0.18384776  -0.18384776]
  sonar_2nd_bank_start  24

  rflex_power_offset    1.2 # volts

  rflex_base_bank 0
  rflex_bank_count 6
  rflex_banks [4 4 4 4 4 4]
  pose_count  24
  ir_min_range  0.100
  ir_max_range  0.800
  rflex_ir_calib  [ 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 4000 -2 ]
  poses [-0.247861 0.032632 -3.272492 -0.230970 0.095671 -3.534292 -0.198338 0.152190 -3.796091 -0.152190 0.198338 -4.057890 -0.095671 0.230970 -4.319690 -0.032632 0.247861 -4.581489 0.032632 0.247861 -4.843289 0.095671 0.230970 -5.105088 0.152190 0.198338 -5.366888 0.198338 0.152190 -5.628687 0.230970 0.095671 -5.890486 0.247861 0.032632 -6.152286 0.247861 -0.032632 -6.414085 0.230970 -0.095671 -6.675884 0.198338 -0.152190 -6.937684 0.152190 -0.198338 -7.199483 0.095671 -0.230970 -7.461283 0.032632 -0.247861 -7.723082 -0.032632 -0.247861 -7.984881 -0.095671 -0.230970 -8.246680 -0.152190 -0.198338 -8.508480 -0.198338 -0.152190 -8.770280 -0.230970 -0.095671 -9.032079 -0.247861 -0.032631 -9.293879 ]
)

Author

Matthew Brewer, Toby Collett