Hamster

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Quick start

1. Install hamster server - multi-master configuration https://wiki.cogni.io/index.php/HamsterServer

(if your robot was shipped before January 2018 - single-master configuration)

2. Turn on robot

3. Control your agents in hamster.perspective -rqt with mouse, joystick and keyboard:

Select window with agent number:

agents 1-10 switching with 1 ... 0 keyboard buttons

agents 11-20 switching with shift + 1 ... shift + 0

4. See your robot in hamster.rviz

For agents 3-20 change agent number in topic names

Hamster system

Hamster versions

Hamster research teams

The Hamster is being used as a research platform at various institutes

Hamster research papers

Hamster models

Robot's components

Each robots has two raspberry pi computers on board - master and slave, and a low level controller.

Master - Has a wifi connection to the hamster network, provides network access to slave. It also connects to the slave computer directly via ethernet cable.

Slave - Second computer, used primarily for GPS data broadcasting, connected to hamster network via master.

Low level controller - Arduino based board responsible for interaction with hardware components.

Operation modes

Hamster robot is capable of running mapping, localization or outdoor localization (using GPS and IMU).

Switching between modes:

In order to change the operation mode publish std_msgs/String message to /mapping_command topic, containing on e of the following strings:

  • slam
  • localization
  • outdoor

Example:

1 rostopic pub /mapping_command std_msgs/String "data: 'slam'"
1 rostopic pub /mapping_command std_msgs/String "data: 'localization'"

When switching from mapping to localization mode, the map is saved by the server, and loaded for localization algorithm.

All maps saved inside ~/hamster_ws/src/hamster_server_launch/maps$

Hamster calibrations and configurations

Hamster F.A.Q

  • Q: What is the Hamster maximum speed
  • A: 1.2m/s
  • Q: What is the Hamster minimum speed
  • A: 0.1 m/s
  • Q: What is the Hamster turning deg sensitivity
  • A: ~1 deg
  • Q: My Hamster turns in place in a suspicious manner. Why is it?
  • A: We call this the Austin Powers turn. This is since the Hamster uses hackerman steering geometry. With 0 linar force and some angular force it results in

Austin.gif

Hamster wireless network

Router

  • SSID 2.4Ghz: hamster_net
  • SSID 5.0Ghz: hamster_net5
  • Password: hamsterHAMSTER
  • Network: 10.0.2.0
  • Netmask: 255.255.255.0
  • Gateway: 10.0.2.138

Hamster

  • User = pi / hamster (on up squared)
  • Password = hamster

Master:

  • IP: 10.0.2.n/192.168.n.1

Slave:

  • IP: 192.168.n.2

n - stands for agent id, e.g agent7 will have 10.0.2.7/192.168.7.1

Low level controller

Hamster LLC connection scheme (for V4 and V5)

Description

The LLC board is responsible for interaction with hardware components such as:

  • Motors (drive and steering)
  • Encoders (mainly used for PID controller)
  • IMU
  • Battery monitoring
  • Cut-off (shuts down the platform when battery goes below certain voltage)

The LLC is connected to master computer via UART (serial)

A built-in switch is also provided for the possibility of loading new firmware (voids warranty, can be provided per request)

Server

Description:

Usually runs ROS master services, it also loads and publishes the map for localization

Note: hamster robot may be configured to use local ROS master to avoid using dedicated server for this purpose

Project:

Master

Description:

Majority of hardware is connected to the master pc, it also acts as network gateway for slave

Hardware

  • WiFi ew-7811uac EDIMAX AC600
  • Camera raspberry Pi module v2
  • LiDar A2M8 (USB)
  • IMU AltIMU-10 v5
  • Ethernet (to slave)
  • Low level controller (via UART)

Slave

Description

GPS data broadcaster

Hardware

  • GPS Mouse - GP-808G
  • Ethernet (to master)

Subcategories

This category has the following 5 subcategories, out of 5 total.