somebodyus's profile - activity

Dear all,

How to pause a mobile robot during navigation? How to make the robot restore after the pause?

In my application, I expect the robot can pause for some while after I set the navigation goal. And restore into the navigation process after the pause.

I am now using turtlebot with ROS navigation stack.

Best Regards, Jack

The statement 'roscore &' offten appears before 'rosparam set /use_sim_time true'.

What's the function of the symbol & after roscore?

Is there any opensource hardware mobile robot platform? Like irobot create2, or Pioneer P3-DX?

I am really confused about the meaning of "depth" which is acquired by a RGB-D camera. I think there are two meanings,

1: The distance from a point in the 3-D world to the infrared camera center.

2: The Z value of the 3-D world point in the camera frame.

Which is right?

If the second meaning is right, the depth values of all the points in a wall which is parallel with the RGB-D camera should be equal, but the fact is not like that. However, many 3-D vision books indicate the second meaning is right. I am really confused. Who can help me?

I have an arduino robot and a Raspberry Pi.

I note that there is a package called ROS arduino. How can I develop a ROS driver to control my arduino robot?

Does there exist any navigation package except the ROS navigation?

I have a mobile robot without wheel encoder. I have a 2D laser range finder. I want to run ROS navigation on this robot.

I notice that amcl can provide tf between /map and /odom. Because I have no wheel encoder, so that no /odom to /base_link tf can be provided.

Does ROS navigation stack need wheel encoder? How can I run the navigation stack on this robot?

I have two PCs in one robot. The PCs are connected using one router. PC1 is selected as ROS master.

I have another two PCs in another robot. The PCs are connected using another router. PC3 is selected as ROS master.

How to communicate between the ROS sub-networks? How to avoid name conflict?

I want to make a mini mobile robot with a mini PC which can run ubuntu.

Is there any opensource hardware product?

Dear all,

I am using move_base for navigation with a SICK laser scanner. I have set the local cost map update frequency to 30Hz. However, the obstacle cannot be cleared timely when the obstacle such as a walking person moved away. The costmap will not be updated until the robot move.

For example, in the attached figure. The walking person in the green axis has moved away, but the costmap cannot clear the obstacle timely. Thus, the robot will be stuck in the virtual corner. The red axis is the robot heading direction.

The parameter settings are:

obstacle_range: 2.5
raytrace_range: 3.0
robot_radius: 0.165
inflation_radius: 0.30
max_obstacle_height: 0.6
min_obstacle_height: 0.0
observation_sources: scan
scan: {sensor_frame: /laser, expected_update_rate: 30, data_type: LaserScan, topic: /scan, marking: true, clearing: true}   

global_costmap:
  global_frame: /map
  robot_base_frame: /base_link
  update_frequency: 5.0
  publish_frequency: 0.0
  rolling_window: false
  static_map: true
  resolution: 0.05
  transform_tolerance: 2.0
  map_type: costmap


local_costmap:
  global_frame: /odom
  robot_base_frame: /base_link
  update_frequency: 30.0 
  publish_frequency: 10.0  
  static_map: false
  rolling_window: true
  width: 6.0
  height: 6.0
  resolution: 0.05
  transform_tolerance: 2.0
  map_type: costmap
obstacle_layer:
    observation_sources: laser_scan_sensor
    laser_scan_sensor: {sensor_frame: laser_link, data_type: LaserScan, topic: /scan, marking: true, clearing: true, observation_persistence: 0.0, expected_update_rate: 0.0, max_obstacle_height: 2.0, min_obstacle_height: -2.0, obstacle_range: 4.0, raytrace_range: 5.0, inf_is_valid: false}
    max_obstacle_height: 2.0
    obstacle_range: 4.0
    raytrace_range: 5.0
    track_unknown_space: false

move_base parameters:

controller_frequency: 3.0
recovery_behavior_enabled: false
clearing_rotation_allowed: false

TrajectoryPlannerROS:
   max_vel_x: 0.5
   min_vel_x: 0.03
   max_vel_y: 0.0   
   min_vel_y: 0.0
   min_in_place_vel_theta: 0.5
   max_vel_theta: 0.25
   min_vel_theta: -0.25
   escape_vel: -0.1
   acc_lim_x: 2.5
   acc_lim_y: 0.0 
   acc_lim_theta: 3.2

   holonomic_robot: false
   yaw_goal_tolerance: 0.15  
   xy_goal_tolerance: 0.15  
   latch_xy_goal_tolerance: false
   pdist_scale: 1.2
   gdist_scale: 0.6
   meter_scoring: true

   heading_lookahead: 0.5  
   heading_scoring: false
   heading_scoring_timestep: 0.8
   occdist_scale: 0.2 
   oscillation_reset_dist: 0.05
   publish_cost_grid_pc: false
   prune_plan: true

   sim_time: 1.0
   sim_granularity: 0.025
   angular_sim_granularity: 0.025
   vx_samples: 8
   vy_samples: 0 
   vtheta_samples: 20
   dwa: true
   simple_attractor: false

Thank you very much, Jack

What does the Fixed Frame mean in rviz?

How to record the movement of a robot arm am play it back? I am using a kinova jaco arm.

Is there any available stack for the movement recording?