LIDAR - What it is, How it works, and How it is used in Robotics

1. Specialization seminar presentation
topic
LIDAR – WHAT IT IS, HOW IT WORKS, AND HOW IT IS USED IN
ROBOTICS
By:
David Ugochukwu asogwa
5th January 2022

2.  What LIDAR is
 Examples of LIDAR devices and properties
 How LIDAR works in general
 LIDAR Application in robotics

3. LIDAR: is an acronym that stands for: LIGHT
IMAGING DETECTION AND RANGING. Also
referred to as “Laser Scanning” or “3D scanning”.
A method for determining ranges by targeting an
object with laser and measuring the time for the
light to return to the receiver. LIDAR is also used
to make 3-D representation of the earth’s surface

4. and ocean bottom. The technology uses eye-safe
laser beams to create a 3-dimensional (3D)
representation of the surveyed environment.
LIDAR is used in making high-resolution maps,
and finds applications in:
 Robotics

5.  Surveying landscapes
 Archaeological Research
 Forest mapping
 Seismology
 Autonomous Vehicles
 Military

6. LIDAR is not actually a new technology as many
have assumed. The first LIDAR-like system was
introduced in 1961, by the Hughes Aircraft
Company, shortly after the invention of the
laser. It was originally called Colidar, an
acronym for Coherent Light Detecting And
Ranging.

7. The TF Mini LIDAR

8. The TF Mini LiDAR, distributed by DFRobots,
Shanghai, is a one-way rangefinder that is based
on ToF (Time of Flight) technology. It consists of
high quality optical and electrical devices that
provide stability, high sensitivity and precision.
These qualities makes the sensor ideally suited
for drone or other unmanned applications.

9. It can work under the influence of 70 lux light,
resistant to interference from temperature,
humidity, light, electronics and air flow. A laser
beam with a wavelength of 850 nm is used for
the measurement and data are transmitted
through the UART serial interface.

10. The TF Mini have the following properties:
 Communication is via the UART interface
which uses TTL.
 Range: ≅0.00 to 12m, minimum is actually
0.3m
 Average Power of 0.6W, with current
consumption of 120mA.

11.  Acceptance angle: 2.3 degrees
 Refresh rate: 100Hz
 Wavelength of 850nm
 Measurement Accuracy: 1% (<6m), 2% (6~12m)
 Working Temperature: 0°
to 60°
𝑐

12. TF Mini LIDAR laser scanner
images

13. Fig. 1: RPLIDAR A1M8
Fig. 2: RPLIDAR A2

14. The RPLIDAR is a low cost 360 degrees 2D laser
scanner. The system can perform 360 degrees
scan within 12-meter range. The 2D point cloud
data produced can be used in mapping,
localization, object and environment modelling.
The sample rate of LIDAR directly decides whether
the robot can map quickly and accurately.

15. RPLIDAR has an improved internal optical design
and algorithm system that makes its sample rate
up to 8000 times.
The properties of the RPLIDAR include:
 360 degree directional laser range scan
 Configurable scan rate from 2-10Hz

16.  Sample frequency: 8,000Hz
 Sample rate: 5.5Hz
 Motor drive system
The core of an RPLIDAR runs clockwise to
perform a 360 degree omnidirectional laser
range scanning for its surrounding
environment and then generate an outline map

17. Fig. 3a: Scanned Room Fig. 3b: Scanned Output from RPLIDAR

21. RFLIDAR System Data Transmission
Data obtained from the receiver system is
transmitted through LED’s and light sensors to the
communication port. This is because the system is
in constant motion and wires cannot be used to
transmit the obtained data to the communication
port.

22. LED and light sensor for data transmission to the communication port.

23. HOW DOES THE LIDAR WORK?
LIDAR uses pulsed laser to calculate an objects
distance from the earth surface. It emits hundreds
of thousands of light pulses per second. These
pulses bounce off surrounding or targeted objects
and return to the LIDAR sensor. The sensor uses

24. the time it takes for each pulse to return and
speed of light (299,792,458 m/s) to calculate the
object distance. These data are processed into a
3D visualization known as a “point cloud”. These
data are recorded in a computer, which is one of
the primary LIDAR components that also includes:
Scanner, Laser and GPS.

25. 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 =
𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑙𝑖𝑔ℎ𝑡 ∗ 𝑡𝑖𝑚𝑒 𝑜𝑓 𝑡𝑟𝑎𝑣𝑒𝑙
2
The above expression is divided by 2 because the
time of flight used is the total time for the laser to
hit the surface and return to the sensor. The
distance tells us how far the light actually travels
to the ground.

26. 𝐺𝑟𝑜𝑢𝑛𝑑 𝑒𝑙𝑒𝑣𝑎𝑡𝑖𝑜𝑛 = 𝑃𝑙𝑎𝑛𝑒𝑠 𝐴𝑙𝑡𝑖𝑡𝑢𝑑𝑒 − 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒
The planes altitude is calculated using the planes
GPS. The above expression is used for calculating
height of objects that are elevated above the
ground level. All measurements are in meters.

29. Types of LIDAR Systems
1. Airborne LIDAR: This LIDAR system is installed
in Helicopter, drones, or air planes for
collecting data. It emits light towards the
ground, which returns to the sensor when it
hits an object, giving an exact measurement of
its distance.

31. 2. Terrestrial LIDAR: Unlike airborne LIDAR, this
LIDAR system is installed on moving vehicles or
tripods on the earth surface for data collection.
They are used for observing high ways, analysing
infrastructure or collecting point cloud data from
the inside and outside of buildings.

33. LIDAR system under test by
mapping the human hand.
Result of the 360 degrees
mapping displayed on the
computer screen

34. How is LIDAR used in Robotics?
LIDAR technology is an essential component in
robotic autonomy and navigation. It allows mobile
robots extend outside controlled situations with
pre-defined tasks and function in unfamiliar and
unpredictable settings. The sensors provide a
constant stream of high-resolution 3D information

35. about the robot’s surroundings, including locating
the position of objects and people and avoids
collision. Lidar enables the robot to not only
identify the presence of an entity but also
determine in real time if it is a human or
object. This allows the robot to assess
appropriate risk behavior models, which is

36. safety in robot-human collaboration. Also,
lidar, which does not recognize the identity of
a person, avoids the privacy problems
created by robots that use cameras as a
sensing technology.
Though most of the attention recently is on
the use of LIDAR in autonomous vehicles,

37.  Distribution Centres: providing more efficient
pick and palletization process in warehouses.

38.  Food and Grocery Delivery: Navigating
sidewalks , pedestrians and more while bringing
hot or cold food to a customer.

39.  Retail: Scanning aisles for product
replenishment needs.

40.  Industrial Automation: providing safety and
efficiency in agriculture, construction, pipeline
and railway inspection.

41.  LIDAR-based autonomous robotics platform
that helps travellers find their way around
airports. This was deployed by a London-based
technology start-up BotsAndUs at Heathrow
Airport in conjunction with British Airways. The
robot also helps travellers have instant access
to accurate information about their journey.

43.  Military Application: Due to its high accuracy,
ability to see through masking items (such as
leaves, trees and camouflaged netting), LIDAR
has found applications in military driverless
vehicles, battle field visualization, mine hunting
and imaging through forests. This has helped in
reducing battle casualties.

44. Military vehicles with mounted LIDAR
sensors for mine hunting and forest
mapping.

45. An autonomous security robot system using the Velodyne LIDAR puck in an
uncontrolled environment.

46. THANK YOU

47. Resources:
1. https://kamami.pl/en/distance-sensors/570405-dfrobot-tf-mini-lidar-tof-laser-sensor.html
2. https://www.instructables.com/TFMini-Lidar-Display-Like-Radar-Only-With-Light-/
3. https://www.slamtec.com/en/Lidar/A2
4. https://www.electronicaembajadores.com/en/Productos/Detalle/SSPXLD5/sensors/proximity-
sensors/rplidar-a1m8-360-degree-laser-scanner-kit-12-m
5. https://elediy.com/products/rplidar-a1m8-360-degree-laser-scanner-development-kit
6. https://www.geospatialworld.net/blogs/what-is-lidar-technology-and-how-does-it-work/
7. https://geoslam.com/what-is-lidar/
8. https://velodynelidar.com/what-is-lidar/
9. https://velodynelidar.com/blog/8-ways-lidar-brings-mobile-robots-to-life/
10. https://www.novuslight.com/lidar-technology-in-autonomous-robotic-systems_N10426.html
11. https://www.generationrobots.com/blog/en/which-applications-for-a-lidar/
12. https://idstch.com/technology/photonics/military-applications-
lidar/#:~:text=The%20military%20depends%20on%20LiDAR,on%20a%20much%20larger%20scale.