Robotics StackExchange | Archived questions

Neato Xv 11 Lidar Hector map keeps jumping

I have been working with the XV11 lidar.. I have been able to display a scan on ros after installing the XV11 Driver. Now i have progressed onto hector mapping.

Installed the hector mapping.. when i run hector_neato.launch file i my map keeps jumping and in the terminal it says

SearchDir angle change too large

and after some time it dies with

[hector_mapping-4] process has died [pid 21496, exit code -11, cmd /home/catkin_ws/devel/lib/hector_mapping/hector_mapping __name:=hector_mapping __log:=/home/.ros/log/bc063610-6871-11e9-a40b-001c4251406b/hector_mapping-4.log].
log file: /home/.ros/log/bc063610-6871-11e9-a40b-001c4251406b/hector_mapping-4*.log

i have heard rpm can sometimes cause bytes to be lost hence I did a test at different rpms. i seemed to get the most stable map at 302 rpm however the map still flickers and is not fully stable with the same "SearchDir angle change too large" i am using a Tip 120 for PWM control of the motor and passing the lidar data through a logic level converter

Asked by fyi on 2019-04-27 17:25:18 UTC

Comments

Answers

The neato lidar will work with Hector, but you need to move and turn the robot very slowly. The mapping will tolerate only small linear and rotational shifts between map updates. Cut your velocity and theta limits in half and try again. You can speed it back up again after mapping.

About the mac RPM, I have one that loses packets often at 300rpm and I slowed it to 180RPM to make it reliably work. You may consider slowing it further unless you have the tools to prove it's working fully at 300rpm.

Asked by billy on 2019-04-27 20:42:59 UTC

Comments

i tried slowing it down to 180rpm and it doesn't like it. it doesn't even show any laser scan and the rpm in the terminal becomes very inconsistent

data: 177
---
data: 177
---
data: 1000
---
data: 1000
---
data: 178
---
data: 177
---
data: 1000
---
data: 178
---
data: 176
---
data: 181
---
data: 179
---
data: 176
---
data: 179
---
data: 182
---
data: 359
---
data: 179
---
data: 174
---
data: 177
---
data: 178
---
data: 177
---
data: 177
---
data: 177
---
data: 176
---
data: 178
---
data: 177
---
data: 177
---
data: 177
---
data: 1001
---
data: 179
---
data: 174
---
data: 328
---

Could it be that the rpm controller is not suitable i.e TIP 120 Transistor? what do you use for rpm control?

Asked by fyi on 2019-04-28 04:53:02 UTC

I don't know what the data you posted is, but if not stable that slow, run it at slowest speed it is stable at. I use the controller in the link. I can't comment on the transistor you are using without additional details, but if the rotation is working OK, then it's OK. https://www.getsurreal.com/product/xv-lidar-controller-v1-2/

Asked by billy on 2019-04-28 23:08:02 UTC

https://drive.google.com/open?id=1TKOQ1cswGefzLSjLM_LUUDj7MaZdc-jb

Please see this link of a screen capture of the problem. maybe im missing something but regardless the map still dies

Asked by fyi on 2019-04-30 04:08:14 UTC