Only released in EOL distros:  

Corobot: PhidgetMotor | PhidgetServo | corobot_arm | corobot_camera | corobot_gps | corobot_hokuyo | corobot_joystick | corobot_map_to_jpeg | corobot_msgs | corobot_pantilt | corobot_phidgetIK | corobot_srvs | corobot_ssc32 | corobot_state_tf | corobot_teleop

Package Summary

This corobot_hokuyo package is just an integration of the package hokuyo_node from Brian P. Gerkey, Jeremy Leibs and Blaise Gassend into the Corobot stack to make it easier for CoroWare's client to setup their robot. A ROS node to provide access to SCIP 2.0-compliant Hokuyo laser range finders (including 04LX).

Supported Hardware

This driver should work with any SCIP 2.0-compliant laser range-finders.

Parameter Ranges

The UTM-30LX laser can report corrupt data and even crash if settings with an excessive data rate are requested. The following settings are known to work:

Intensity mode off:

  • cluster: 1

  • skip: 1

  • intensity: false

  • min_ang: -2.2689

  • max_ang: 2.2689

Intensity mode on:

  • cluster: 1

  • skip: 1

  • intensity: true

  • min_ang: -1.047

  • max_ang: 1.047

Allow Unsafe Settings Option

On the UTM-30LX, unless the ~allow_unsafe_settings option is selected, the hokuyo_node will limit the angular range to values that are known to work. The angular range limit depends on the firmware version, and is proportional to the cluster parameter.

Firmware version

Maximum angular range / cluster (deg)

hokuyo_node version

1.16.01(16/Nov./2009)

190

> 1.1.1

1.16.02(19/Jan./2010)

95

> 1.0.3

Other

95

> 1.0.3

ROS API

corobot_hokuyo

corobot_hokuyo is a driver for SCIP 2.0 compliant Hokuyo laser range-finders. This driver was designed primarily for the Hokuyo UTM-30LX, also known as the Hokuyo Top-URG. The driver has been extended to support some SCIP1.0 compliant range-finders such as the URG-04LX. Hokuyo scans are taken in a counter-clockwise direction. Angles are measured counter clockwise with 0 pointing directly forward.

Published Topics

scan (sensor_msgs/LaserScan)
  • Scan data from the laser.
diagnostics (diagnostic_msgs/DiagnosticStatus)
  • Diagnostic status information.

Services

~self_test (diagnostic_msgs/SelfTest)
  • Starts the Hokuyo self test, which runs a series of tests on the device. The laser stops publishing scans during the test, which takes about a minute. The result of the test is in the response returned by this service. At the conclusion of the test, the laser is returned to its normal operating mode.

Parameters

Dynamically Reconfigurable Parameters
See the dynamic_reconfigure package for details on dynamically reconfigurable parameters.
~min_ang (double, default: -π/2)
  • The angle of the first range measurement in radians (range is [-π,π], though most devices have a smaller feasible range).
~max_ang (double, default: π/2)
  • The angle of the last range measurement in radians (range is [-π,π], though most devices have a smaller feasible range).
~intensity (bool, default: false)
  • Whether or not the hokuyo returns intensity values.
~cluster (int, default: 1)
  • The number of adjacent range measurements to cluster into a single reading; the shortest reading from the cluster is reported.
~skip (int, default: 0)
  • The number of scans to skip between each measured scan. This controls the update rate. For a UTM-30LX, the hokuyo will scan at 40Hz, so setting "skip" to 1 makes it publish at 20Hz.
~port (string, default: /dev/ttyACM0)
  • The port where the hokuyo device can be found.
~calibrate_time (bool, default: true)
  • Whether the node should calibrate the hokuyo's time offset on startup. If true, the node will exchange of series of messages with the device in order to determine the time delay in the USB connection. This calibration step is necessary to produce accurate time stamps on scans.
~frame_id (string, default: laser)
  • The frame in which laser scans will be returned. This frame should be at the optical center of the laser, with the x-axis along the zero degree ray, and the y-axis along the 90 degree ray.
~time_offset (double, default: 0.0)
  • An offet to add to the timestamp before publication of a scan Range: -0.25 to 0.25 (New in release 1.0.1)
~allow_unsafe_settings (bool, default: False)
  • Turn this on if you wish to use the UTM-30LX with an unsafe angular range. Turning this option on may cause occasional crashes or bad data. This option is a tempory workaround that will hopefully be removed in an upcoming driver version. (New in release 1.0.3)
Read-only parameters
~max_ang_limit (double)
  • Read only parameter indicating the smallest allowed value for ~min_ang on the currently connected device.
~max_ang_limit (double)
  • Read only parameter indicating the largest allowed value for ~max_ang on the currently connected device.
~min_range (double)
  • Read only parameter indicating the smallest distance that can be measured by the currently connected device.
~max_range (double)
  • Read only parameter indicating the largest distance that can be measured by the currently connected device.

Parameter interactions

Some parameter settings can cause problems, usually due to speed limitations of the laser's serial interface. For example:

  • if intensity is true and skip is 0, then the device will likely drop some scans;

  • if intensity is true and min_ang / max_ang are outside -70 / +70 degrees, then some problems have been observed.

Wiki: corobot_hokuyo (last edited 2012-11-05 21:42:00 by MorganCormier)