This document summarizes an embedded research project involving Lidar-based obstacle detection for a vehicle from March to June 2019. The project used a XV11 Lidar sensor with a Raspberry Pi on a ROS platform to detect obstacles based on vehicle speed and provide warning and emergency braking zones. Challenges included interfacing the Lidar, processing data, and developing dynamic zones and motor control for an RC model car. Software was created to detect obstacles based on direction and steering angle and provide warning and braking signals to slow or stop the vehicle. The system was tested and validated on the RC car.

1. EMBEDDED RESEARCH PROJECT
LIDAR BASED OBSTACLE DETECTION
March 2019 – June 2019
Vishal Mishra
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2. Introduction:
• Behavior of vehicle is determined by Lidar Laser Readings.
• Depending on speed and steering angle , obstacle detection is determined by the
vehicle.
• Two thresholds zones are defined by the system. First is warning and the second is
emergency breaking zone.
• The extremities of zone is dependent upon the vehicle speed. For example : if
vehicle is moving at a lower speed, nearby obstacles are detected and if the
vehicle is moving at a higher speed , far distance obstacles are also detected.
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3. Challenges :
• XV11 Lidar Interfacing with Raspberry Pi on ROS platform
• Processing the XV11 laser data into an understandable format.
• Determination of DynamicWarning and Emergency Zones ranges depending on
Vehicle Speed
• Development of Motor Control Unit for RC model Car
• Developing a complete Dynamic System on ROS platform
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4. Vehicle Control Planning:
• Check the lidar data for obstacle in your field of view
• Depending on speed, direction of the car and especially on the steering angle,
decide whether or not the object blocks your vehicle
• Provide two thresholds: t1 for warning distance, t2 for emergency break assist
• If the distance above is lower than t1, set a warning signal (e.g. yellow light or low
beep)
• If the distance above is lower than t2, set an emergency break signal (e.g. yellow
light or low beep) (the signal can be used by the steering project above)
• Test and validate on RC model car (either simple warning signal or in combination
with the steering project above)
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5. Software Development:
• Define the all regions for obstacle detection by LIDAR sensor “ front, fright, fleft, left,
back, bleft, bright
• Get speed , Angle and direction from topic published by steering team
• Based on speed and friction coefficient will find threshold values for warning and
emergency brake signal.
• Based on direction detect obstacles only in that direction.
• Based on steering angle, detect obstacles in that range
• Once the vehicle is in warning zone, publish reduced speed values to steering team and
glow aYELLOW LED indicating an approaching obstacle.
• Once the vehicle is in emergency zone, publish Zero speed value to steering team for
emergency brake and glow the RED LED .
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6. Software Development Flowchart :
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7. Lidar Interfacing with the Raspberry Pi:
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8. RC car motor-
control circuit:
• This setup is used to control the motor
of the wheels of RC model car.
• When the vehicle approaches the
obstacle in the breaking zone, this
circuit is used to bring the car at rest.
• Reference :
https://business.tutsplus.com/de/tutori
als/controlling-dc-motors-using-
python-with-a-raspberry-pi--cms-
20051
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9. Distance
calculation:
• Reaction distance:
(veh_speed)^2/(20,000 * f)
• Braking distance:
(veh_speed)^2/(10,000* f)
• .f = 0.8 (friction coefficient)
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10. Results:
• Obstacle Detection based on direction
and steering angle.
• Warning Signal is provided if vehicle
enters in warning zone limit.
• Speed values are linearly reduced and
published to steering team.
• Zero Speed values are provided when
vehicle enters emergency zone.
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11. SampleVideo:
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12. THANKYOU !!
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