# Revision history [back]

### Why does the DWA Local Planner need an acceleration value of >= 1.0?

Sometimes, in cluttered environments, our (differential wheeled) robot seems to accelerate too fast and navigates itself into places it cannot escape from. Just to test if a lower acceleration would do any good I tried reconfiguring it but it seems that setting the parameter /move_base/DWAPlannerROS/acc_lim_x lower than 1.0 causes move_base to not do anything any more. Since the parameter is a float value, I expect that the reason is not just an int cast somewhere. Does anyone know why an acceleration lower than 1.0 m/s^2 might not be supported?

### Why does the DWA Local Planner need an acceleration value of >= 1.0?

Sometimes, in cluttered environments, our (differential wheeled) robot seems to accelerate too fast and navigates itself into places it cannot escape from. Just to test if a lower acceleration would do any good I tried reconfiguring it but it seems that setting the parameter /move_base/DWAPlannerROS/acc_lim_x lower than 1.0 causes move_base to not do anything any more. Since the parameter is a float value, I expect that the reason is not just an int cast somewhere. Does anyone know why an acceleration lower than 1.0 m/s^2 might not be supported?

Edit: Just to give some more info, these are the other parameters we use:

DWAPlannerROS:
acc_lim_x: 1.0

acc_lim_y: 0.0

acc_lim_th: 2.0

min_vel_y: 0.0
max_vel_y: 0.0
max_rot_vel: 1.0
min_rot_vel: 0.4

yaw_goal_tolerance: 0.1

xy_goal_tolerance: 0.3

latch_xy_goal_tolerance: true
sim_time: 1.7

path_distance_bias: 5.0 #default:32
goal_distance_bias: 9.0 #default:24
occdist_scale: 0.01 #default:0.01

oscillation_reset_dist: 0.05

prune_plan: true

holonomic_robot: false


Not listed parameters use the default values.

### Why does the DWA Local Planner need an acceleration value of >= 1.0?

Sometimes, in cluttered environments, our (differential wheeled) robot seems to accelerate too fast and navigates itself into places it cannot escape from. Just to test if a lower acceleration would do any good I tried reconfiguring it but it seems that setting the parameter /move_base/DWAPlannerROS/acc_lim_x lower than 1.0 causes move_base to not do anything any more. Since the parameter is a float value, I expect that the reason is not just an int cast somewhere. Does anyone know why an acceleration lower than 1.0 m/s^2 might not be supported?

Edit: Edit: Just to give some more info, these are the other parameters we use:

DWAPlannerROS:
acc_lim_x: 1.0

acc_lim_y: 0.0

acc_lim_th: 2.0

min_vel_y: 0.0
max_vel_y: 0.0
max_rot_vel: 1.0
min_rot_vel: 0.4

yaw_goal_tolerance: 0.1

xy_goal_tolerance: 0.3

latch_xy_goal_tolerance: true
sim_time: 1.7

path_distance_bias: 5.0 #default:32
goal_distance_bias: 9.0 #default:24
occdist_scale: 0.01 #default:0.01

oscillation_reset_dist: 0.05

prune_plan: true

holonomic_robot: false


Not listed parameters use the default values.

Edit2: To answere David's comment: These are the parameters we use for the local costmap:

local_costmap:
update_frequency: 5.0
publish_frequency: 2.0
static_map: false
rolling_window: true
width: 4.0
height: 4.0
resolution: 0.05
plugins:
- {name: obstacle_layer, type: "costmap_2d::VoxelLayer"}
- {name: inflation_layer, type: "costmap_2d::InflationLayer"}


So the resolution is 0.05 which is the default value if I'm not mistaken.