Firefighting Drone using Fire Suppressant Balls

Firefighting Drone using Fire Suppressant Balls

Deepak Kumar Department of Electronics and IT Karlsruhe Institute of Technology

Karlsruhe, Germany

Vishal Gupta

Department of Mechanical Engineering Karlsruhe Institute of Technology Karlsruhe, Germany

Abstract As the development in innovation and improvement in smart cities, the administrations for firefighting have become even more challenging to adapt the idea of smart cities. One of the most common difficulties which firemen are confronting is to reach at the highest levels of multi floor structures, and even to reach the firemen requires weighty and bulky hardware to arrive at highest levels, which they occasionally neglect to follow through on schedule because of enormous urban communities' traffic. The proposed answer for this worldwide issue is utilizing firefighting automated airborne vehicle (UAV) to arrive at the highest levels quick and productively. It can likewise offer a superior vision to the firefighting group and proposing the use of fire suppressant ball. These balls dropped into the flame, where it initiates and spread a dry fire extinguishing powder. These fire suppressant balls put off A, B or C class fires. In this paper, an idea for a firefighting unmanned vehicle that is, a drone is used with shooting as well as dropping mechanisms. The other component of drone involves using laser for range detection. A camera is also integrated to increase the capability of drone with night vision that can give accommodating guide to firemen. The thermal imaging camera could be utilized to detect the presence of fire, it likewise demonstrates the presence of individuals who were caught in the structures, and they can be seen as effectively even within the sight of smoke, where the fire fighters could not operate directly

Keywords UAV (Unmanned vehicle), FCB (Flight controller board), Fire suppressant ball, Arduino, RF transmitter

1. INTRODUCTION

   Drones are essentially flying unmanned vehicles which can be controlled by a trained professional or made to take flights independently with the help of softwares involving different programming languages in their embedded system (PLC). The drones need to become savvy and intelligent to upgrade current industrial processes, augment their utility and can be broadly settled in later factories. This innovation offers different applications not just in the field of aerial reconnaissance and checking, yet in addition firefighting tasks. On 4 August 2016, National geographic used ping pong size fire suppressant balls. They used a drone to control fire in the forest where a small fire can lead to big disaster because of dry wood on the forest land. This helped firefighters who try to stop these small-scale fires which eventually prevented the big forest fires.[1]

   As there are huge innovation upgrades in trend, from small scale machines to big construction machines, independent companies to some large corporations, the firefighting administrations are also using new technologies to increase their efficiency in stopping fire to reaching on time to situation analysis in case of fire. The applications of UAV have already expanded in the last couple of years. UAVs are the essential part of this century, from traffic to examine the solar panel

   establishment. With the improvement of savvy urban areas, these unmanned vehicles are utilized in a broad scope of uses. They are very much adaptable in doing tasks that are very troublesome or risky for people to perform. A few investigations on UAV were done by some fire-fighters to investigate how cost effective is using UAV in case of fire. The drones (UAVs) used by firemen mostly center around investigating the place of incidence with a thermal vision camera, but they don't have an independent system for fire dousing purposes. Different researchers thought of water tank arrangement in drone or by using a pipe from ground and using drone to spray water but one of the biggest challenges was stability of drone.

   Fire suppressant balls, which are used to stop fire can be utilized to restrict the further spread of blazes and resolve the stability problems, when handled accurately. In the 19th century, the containers made from glass were used in which fire suppressant fluids was stored and were used to stop fire when required. But, over the time "glass ball" turned out to be less popular to numerous clients. The use of glass containers for fire extinguishing application was made out of order such that glass was no longer employed, yet it is underlying with froth packaging and use of PVC come into place. One of the features of PVC was that it can counters and responds to hotness or fire rapidly, which eventually triggers embedded systems inside the PVC unit to react quickly and scatter the dry synthetic fire suppressant filled inside of ball. In order to initiate, these fire balls should be thrown, tossed or must keep in close range to the fire. Therefore, at that point, it activates or triggers, and spreads out the dry fire suppressant powder.

   In this paper, we are proposing an idea for using a drone UAV with a dropping and shooting mechanism. The drone throws the fire suppressant ball that assists firemen to diminish the further spread of fire in risky situations. This paper gives a theoretical approach to assist fireman with stopping the fire and give an real time surveillance of an area. The overall goals are planning and fostering an automated airborne vehicle (UAV) to help firemen and people in killing fire.

2. SYSTEM REQUIREMENTS

   The proposed drone in this paper is utilizing the hexacopter configuration. With this configuration, the required amount of thrust will be delivered by the brushless DC motors having defined propellers (explained in section System Requirements). When the quadcopter arrangement is utilized, one of the problems is the size of every propeller must be enlarged, so that it can deliver similar thrust as in hexacopter configuration.

   1. Fire suppressant balls

      The development of the fire suppressant ball is a progressive innovation which undeniably furthers the firefighting applications than the conventional fire extinguishers. The use of these fireballs is easy and gives full time protection as they are self-triggered, when in close proximity to fire without any human interventions. Also, weight of the ball plays a crucial role as it comprises the payload of drone. There is different size of balls available ranging from 400 gm to 1.5 kgs. For this paper, we are using the 400 gm balls because of their compact size which enables the drone to carry more balls at same time as well as their fire extinguishing area of approx. 60cm2.

      Figure 1: Mini (400gm) Fire suppressant ball [2]

   2. Thermal imaging camera and its battery

      The camera Yuneec H520 [3], is an innovative mix of 3- pivot gimbal, thermal imaging, and low-light camera. The coordinated 3-hub gimbal can be endlessly pivoted 360°. This mechanism gives an uninterruptedly turning 360° all-round view without moving the drone. Thermal imaging is important for applications, for example, solar panel review, fire administrations, search and salvage, and real estate development and evaluation. The camera conveys thermal pictures, but at the same time can do surveillance with the residual light camera in nightfall or in dim environmental situations. A 4 cell 4000 mAh lithium polymer battery used which provide 14.8 V.

      Figure 2: Image on left is thermal imaging camera and image on right is battery for camera and other small electric components in the drone.

   Brushless DC motor with propellers, ESC and battery

   U12 II KV60 Motors [4] are being employed using for the drone. Outer runner brushless DC motor is used in this drone that houses the extremely durable magnets. The rounds per minute of the electric motor can easily be controlled by fluctuating the input current. The thrust produced by this motor is 19 kg. The motor is dust and waterproof which makes them extremely durable. The propeller utilized is of

   length 30 inches and has a pitch of 10.5 inches [5]. Also, the propellers are made from epoxy and carbon fiber which make them exceptionally light weight against the regular propellers. These propellers additionally have high weight to strength proportion. ESC utilized for this drone is FLAME 80A [6]. The choice of ESC depends upon the motor and battery employed. Battery should match the power requirements of the motor and electric speed controller. We have employed 44000 mAh lithium polymer battery with 44.4V and 25C charge release rate

   Figure 3: Image on top left is propellers used for motor and image on right is motor used, and image on bottom left is ESC for motor.

   3. Flight control board with RF transmitter and receiver

      Use The flight controller board is referred as the brain of the drone. FCB regulates the motion and auto level controlling. There are different FCBs and vary from case to case. The FCB facilitates in communication sensing and controlling the drone. One of the useful features of the FCB is, it receives the incoming signal and perform the commands depending on the input of the person controlling the drone. Pixhawk 4 [7] Flight regulator can be utilized in the drone which empowers an autopilot feature. Taranis X9D+ SE 2019

      [8] is used as transmitter and X8R [9] is used as receiver for drone.

      Figure 4: Image on left is Pixhawk 4 (FCB), image in the middle is wireless RD receiver for drone and image on right is RF transmitter (Taranis

      X9D+ SE 2019).

   4. Arduino with laser LIDAR and servo

      Arduino microcontroller [10] is used here to control the laser LIDAR and servo motor attached to shooting mechanism. A laser LIDAR sensor is used for accurate range detection that helps in precise dropping and the shooting of

      fire suppressant balls. In this project the TF Mini LiDAR TOF (Time of flight) Sensor is used. It can measure a distance up to 12m. This sensor will be interfaced with Arduino for further processing.

      Figure 5: Image on the left is laser range finder and right is Arduino

      micro controller.

   5. Frame of drone

   The frame of the drone [11] will be having 6 motors and all the shooting mechanism will be mounted below the drone. The thermal camera will be in between the shooting mechanism and drone base.

   Figure 6: Shape of drone.

   Weight Calculation of drone with payload:

   PARTS USED	WEIGHT of Parts (Gm)
   4 Fire extinguisher Balls	1600 gm
   Camera	300 gm
   Lithium polymer battery of camera	670 gm
   Laser	10g
   6 Motor	4818 gm
   6 Propellers	2000 gm
   6 Electronics Speed	670 gm
   Frame Structure of drone	8000 gm (approx.)
   Battery for motors	3000 gm
   Flight controller	140 gm
   All other components	2000 gm
   Mechanical shooting and storing the balls	10000 gm
   RF Controller Tx and Rx	2500 gm
   Total	35708 gm (approx.)

   Calculation of Thrust

   Thrust delivered by one propeller and one motor = 19014 gm. Total thrust from 6 motors at 100 percent RPM = 6 x 19014

   =114084 gram

   Thrust to weight (T/W ratio) proportion is total Thrust delivered divided by complete weight of drone

   = 114084/35708

   = 3.19: 1

   With T/W = 3.19, the drone would have better mobility and an additional payload of 8-9 Kg can be carried that makes the T/W ratio of 2.5: 1 and therefore is a good parameter for mobility.

   Battery drain time estimation

   Battery will be utilized to supply power to 6 motors. Total Current from battery = 44000 mAh

   Current consumed by each motor at full RPM = 41 A For all motors, total current consumed= 246 A

   Time the battery last at 100% RPM = 44000 mAh / 246 A

   = 44 A x 60 min/ 246 A

   = 10.7 minutes (approx.) However, we can utilize extra batteries to increase the flight time. Assuming we add 1 or 2 additional batteries, the flight time will have an increment to over 25 minutes (approx.)

3. WORKING Before The drone has 2 sections:

   1. Flying Part

   2. Shooting/Dropping Mechanism.

   The flying part which includes the drone frame, motors, propellers, and other components, is common to other drones, but with high payload carrying capacity. A RF transmitter will transmit a signal which will be received by the receiver of the drone. Then, the signal goes to the FCB where it sends the received and processed signal to other electronic sensors as displayed in the figure 6. Also, FCB have inbuild accelerometer and gyroscope sensor, which would be used to balance off the recoil force generated after shooting the ball and keep the drone stabilized mid-air.

   Figure 6: Flow chart of drone flying working.

   The other feature which the drone employs is shooting and dropping fire ball mechanism. This feature makes the drone useful in worse scenarios in which if a multi-storey building is on fire and fire fighters do not have access to go inside the building, this feature can help the fire fighters to suppress the fire to some extent, so that they can make their way inside of the building. This mechanism consists of detecting the range, how far is the building from the drone and then decide whether to drop or shoot the ball inside the building. The purposed mechanism has a range of 5 meters.

   The shooting/dropping mechanism comprises of spring and servo motor in a cylindrical housing. Servo motor is used to recoil the spring with the help of lever arm mechanism. When the current is cut off from the motor, the spring exert its compressive force on the ball and the spring comes back to its equilibrium state. This spring force is used to shoot the ball out of the muzzle attached to the mechanism. The housing compartment stores the balls, which is designed to carry 4 balls at a time.

   Figure 7: Side section view of 2D CAD model of shooting/dropping mechanism

   Arduino microcontroller is used to control the servo motor used in the proposed method. The special Y design of the storing chamber maximizes its packing efficiency without making the drone bulky. Total of 4 balls are used in this mechanism. 3 balls are being stored in the storage container making the drone symmetric and balanced.

   Figure 8: Flow chart connection between arduino and sensors.

   Additionally shooting mechanism also features a dropping mechanism which can be employed as per the requirement in case of roof of the structure or if an open field is on fire. To facilitate this feature, the spring is to be further recoiled which opens the dropping hole as represented in the pictures above. The dropping hole has an offset of 20 mm to that of storage chamber hole.

   Calculations:

   Figure 10: Projectile trajectory

   y

   y

   Range of projectile R = (Vx) x ( Vy +(V 2+2gh)1/2)/g 1

   g = Acceleration due to gravity = 10 m/s2 As defined above our max range is R = 5 m

   Vy = 0

   h = 5 m

   Substituting the values in the equation 1 We get,

   Vx = 11.2 m/s

   Calculating the acceleration of ball leaving the muzzle

   2 2

   2 2

   Vx – Ux = 2 x a x s 2

   where,

   a = Acceleration of ball leaving the muzzle

   s = Distance of ball travelled in muzzle = 0.25m Ux = Initial velocity of ball inside the muzzle = 0

   Substituting these values in equation 2, we get a = 250.9 m/s2

   For the calculation of maximum force (F) required to accelerate the ball in the muzzle,

   F = m x a 3

   where,

   m = mass of the ball = 0.4 kg

   Substituting the required values in equation 3, we get F = 100 N

   Now, using Hooks law

   F = -k x x 4

   where,

   F = Spring force = Maximum force = 100N k = Spring constant

   x = Displacement of the spring recoiled = 0.1 m Substituting the required values in equation 4, we get

   k = 1000 N/m

   The result obtained is the value of the spring constant (k) used in the shooting mechanism.

   Note: In all the calculations, the air resistance is not considered.

   Figure 9: Side view of CAD 2D shooting/dropping mechanism

4. ADVANTAGES