FIELD OF INVENTION
The present invention is in the field of safety of the operational dumpers/other huge sized vehicles and
their drivers in the open pit mines. The system allows the drivers to safely navigate the vehicle avoiding
collision with other vehicles/human beings/objects in the vicinity.
Harsh mining conditions in the open pit mines pose a great challenge in maintaining safety in operation.
Lots of fatal accidents occur due to
a. Poor visibility
b. Lack of concentration of driver
c. Failure to detect approaching vehicles at the blind spots of a dumper
The heavy vehicles operating in the open pit mines need to maneuver carefully in order to avoid mishap.
Therefore, the problem of safely carrying on the production and operation in open cast mine without
any fatal accident, ensuring workers' safety and safeguarding the costly mining equipments against
collision is identified as a major challenge in open-cast mines. The Audio-visual alert based collision
avoidance systems in driver's cabin would provide significant assistance to the operators of those
Dumpers and other vehicles to safely drive their vehicles avoiding the risk of collision during its course of
normal movement. The dumper collision avoidance systems is necessary to warn the driver against
probable collision with other operating vehicles in the nearby region, and to identify the obstacles on
the way and during backing up of dumpers.
In proposed invention of Dumper Collision Avoidance System for dumpers provides a secured shield
surrounding a dumper. Any other vehicle/jeep/car/human entering its shield area would create an
automatic alarm to the driver of that dumper. Collision with surrounding fixed hazards like Coned off
areas, dump stations, crib huts can also be avoided with this.
The system of the invention will have the mining companies as its end user. The collision avoidance
mechanism will not only improve the safety in the operation of open pit mines but also reduce the
operational and maintenance cost of the expensive mining assets such as the dumpers. Further more,
the system of invention can be augmented to improve the safety of the public transport vehicles.
BACKGROUND ART
Vehicular anti-collision system has received wide spread attention over last couple of decades. Collision
warning systems (CWS) are traditionally classified into two categories. Initial work focused on systems
where a vehicle would gauge obstacles in its path through the use of cameras, radars, acoustic systems,
etc where each vehicle is autonomous and is capable of detecting obstacles, even of heterogeneous
types. However, such devices are cost prohibitive Further, research has progressed to identify potential
collisions between moving vehicles meeting at a cross road. In such systems, Inter Vehicular
Communication is necessitated between vehicles that are not in the line of sight. Inter vehicular
communication has received wide spread attention with the near ubiquitous nature of 802.11. A
collision warning system based on inter vehicular communication involves the broadcast of the vehicle
coordinates and other information like speed and direction on a wireless channel. These systems are
thus known as cooperative CWS (CCWS). A CCWS cannot identify heterogeneous obstacles, however,
based on the propagation property of the wireless system they can see through buildings to reduce
blind spots. Numerous studies have been made on CCWS where GPS data including speed and direction
are transmitted to other vehicles using 802.11.
A common assumption of such systems is the homogeneity of vehicles, where the dimension of each
vehicle does not feature in the determination of collision boundaries. Further, the future position of a
vehicle is estimated by the vehicle receiving the broadcasted information.
In this present invention, we deviate from the conventional CCWS in three aspects. Firstly, every vehicle
based on its direction of travel computes, in longitude and latitude, the four corners of its safety zone.
Thus vehicles of varying profiles are integrated. Secondly, the safety zone is made a function of the
speed, acceleration and the braking power of the vehicle. For example, a vehicle traveling at high speeds
would require a longer braking distance to successfully avoid a collision. This is made possible by
warning the user in advance by having a longer front (F). Similar dimensions can be obtained for a
vehicle whose stopping power is compromised. Thirdly, we utilize the newly ratified 802.15.4 standard
for inter vehicular communication. We use commercial off-the-shelf GPS devices which have a precision
of 7 meters. The IEEE 802.15.4 standard was specifically designed for low data rate and low power
consuming ad hoc communication system. They are able to provide a line of sight range of around a
kilometer and a non-line of sight of around 100 meters. In comparison with 802.11, the memory
requirement of 802.15.4 is small, easily implementable and power requirement is low. The data rates
supported are a theoretical maximum of 250 kbps (kilo bits per second).
OBJECTS OF THE INVENTION
The objective of invention is to offer fail-safe multi-stage warning signal to avoid collision in the
following scenario:
1. Avoiding dumper-to-dumper collision during operation (Early Warning):
Each dumper is equipped with wireless master controller units with an operating communication range
of 100 meters. The primary use of the master controller units are to create a stable inter vehicular
wireless ad hoc network for information exchange. Inter-vehicular wireless network of the system
conforms to the IEEE 802.15.4 standard for low power short range wireless communication. The master
controller units are interfaced with accurate GPS, orientation and heading analyzer (digital compass),
rugged display unit and audible buzzer unit. Each dumper calculates its accurate GPS location and
orientation in real time and broadcast it through its master controller units, placed at the front and back
of the dumper, so that other dumpers in its vicinity can get updates about its present location and
movement pattern. Each dumper thus becomes aware of the location and movement pattern of all the
dumpers in its 100m vicinity. The relative location and movement patterns of all the dumpers in the
surrounding 100m region is displayed and constantly updated on the rugged display panel in the driver's
cabin. This system visually assists the driver to control his vehicle properly avoiding collision with other
dumpers in its vicinity.
Using a positioning algorithm and the received location data from nearby dumpers, each master
controller automatically creates a virtual safety shield around itself and each nearby dumper (as shown
in gray contour around each dumper icon on the display panel in figure). As and when safety shields of
two near-by vehicles overlap, an early warning is generated in the driver's cabin of both the vehicles.
2. Avoiding dumper-to- dumpers collision: Proximity warning
Each dumper is fitted with five RF proximity sensoring devices that are manufactured by PervCom
Consulting to protect collision from four sides. Two RF proximity sensors are fitted in the front, and one
at the rear end of the dumper. The other two RF proximity sensors are fitted on each side of the dumper
with only transmitting capability. If a dumper approaches towards any other dumper (mobile or
stationary) from any side, then the approaching dumper gets RF signal from the corresponding RF
sensor of the other dumper and will get warning signal.
3. Avoiding collision with static and mobile objects (like jeeps, cars, field workers) during
prestart, backing up, and normal operation
Radar based object detection system is integrated at the back and front side of the dumper as an
additional safety measure. This object detection sensor not only detects objects like jeeps, cars, field
workers in the front and back of the dumper but also generates alarm to the dumper operator of
imminent danger. The rear object detection unit is only functional in reverse gear operation. The front
object detection is functional depending on the velocity and orientation of movement of dumper. The
alarm conditions can be customized based on user requirement.
A rear-view camera unit at the backside of the dumper is also integrated to capture and display the real-
time image of the backside of the dumper. Driver, after being sure that no object (static/ mobile) is
there in its back side, will start reversing. Camera stops automatically after backing process is complete.
A Small Vehicle Detection Unit will be placed in designated small vehicles which computes the actual
position of the vehicle and wirelessly broadcasts the position to the nearby dumpers in real time so that
the dumper operator is aware of their position and navigate safely.
DETAILS OF THE INVENTION
The Automatic Dumper Collision Avoidance system has the following functionalities -
• Each dumper is fitted with automatic wireless collision warning unit comprising of accurate
positioning device, display unit, wireless communication device, central processing unit and proximity
sensors (Front, Rear and both sides).
• The system has multi-layer warning mechanism incorporated using relative positioning of vehicles in
motion & wireless obstacle detection techniques to generate audio-visual alerts.
• Accurate Positioning device of each vehicle captures the location, direction of the vehicle's movement;
this information is processed in the central processing unit in the dumpers and communicated with the
other operating vehicles (dumpers, small vehicles) through the master wireless communication unit
within a range of 100 meters.
• The master wireless communication units of each vehicle receives the positional information
broadcasted by other vehicles inside the mine and send it to the Central Processing Unit for further
processing. The inter-vehicular wireless communication network is set up conforming to IEEE 802.15.4
standard and using 2.4 GHz ISM band.
• The central processing unit of the dumper parses the received data to display the relative positioning
of the other vehicles (which are also fitted with wireless collision prevention warning system) in a color
graphical display. The display is dynamic and updates the relative location of other vehicles in every
second.
• The dumper operator gets constant visual updates (with update frequency of maximum 1.5 seconds)
in the cabin display unit about the relative location, movement pattern of the approaching dumpers,
small vehicles (fitted with the same system) present within its 100 meter vicinity and around 360 degree
of the dumper. The visual display always shows the self dumper at the center of the screen. The
movement pattern of other vehicles (dumper, small vehicles) is displayed graphically and in motion with
respect to the direction and movement of self dumper. The identity and approximate distance of the
other dumpers is also depicted in the display screen.
• Upon receiving the accurate position, direction of movement and the speed of the dumper, the
System computes a virtual safety contour (vertically symmetrical heptagon with uneven side) for the self
dumper. When the safety contours of the dumpers overlap, the system generates audio visual early
warning through the display monitor and speakers, so that the operator can judge from where around
the dumper the collision scenario is generated and eventually take action to avoid the near collision
scenario.
• The virtual safety contour of the dumper is adaptive with the speed of the dumper and when static the
contour turns rectangular to match the shape of the dumper. Thus, increased speed of the dumper will
increase its front safety clearance in real time. Under static condition the side safety clearance of the
dumper is 2 meters and rear safety clearance is 5 meters and the front safety clearance distance is a
vector of current speed of the dumper with minimum static range 5 meters.
• The System is able to record the events pertinent to the dumper on which it is mounted and act as a
black box. The information is retrievable/ downloadable and can be used to play back in case of a
collision or near collision scenario.
• In breakdown condition when no power is available in the dumper for proper operation of the System,
the wireless master communication unit derives power directly from either the vehicles battery or its
own battery to broadcast its current location to the other operating dumpers.
• The wireless radio frequency proximity sensors are mounted at the Front, Back and both Sides of the
dumper. The primary function of the wireless proximity sensors are to communicate with other
proximity sensors of the dumpers fitted with the same system to identify safe operating distance, and
generate alert in the operator's cabin in case of violation of predefined safety clearance. The side
proximity sensors acts in transmitter mode only and the front & rear proximity sensors acts as both
Transmitter and Receiver of Proximity information. As backup mechanism, if in case ever the Positioning
System fails the proximity warning system always able to generate alert while the dumper is in
operation.
System Logic of Prposed Dumper Collision Avoidance System
Components:
1. Master Device: Two RF transiver devices are high power 802.15.4 devices connected via
RS232 ports. The master devices are used for broadcasting the data sent by the
software. Because of heavy metallic body of the dumper, any other dumper at the back
side can miss the data broadcasted by the front master. So two masters (front and back)
are used for minimize data loss throughout all direction.
a. Addressing Scheme: Broadcast mode. The intended receiver address is OxFFFF.
b. Operating Channel: 15
c. Baud Rate: 115200
d. Power consumption: High power
e. Data broadcast interval: Whenever any valid GPRMC message is received by the
software from the GPS receiver, the software updates the global data structures,
creates a new master packet and transmits it via both of the master devices. So the
data transmit interval of master packet is about 1200 milliseconds. Master packet
contains information like GPS coordinates, Bearing angle and Speed. Another type of
packets (Information packet) are sent by the master devices at about 2000 ms
interval. These packets are used for sending extra information like Dumper's physical
name, Status flags etc.
f. Packet structure: Two types of packets are sent via master devices.
• Master packet: $M0022244561088302140092902343;
o "$" Starting delimiter
o "M" Packet type (M for master packet)
o "002" Dumper ID (3 digit numeric identifier from 1 up to 999)
o "2244561" Latitude in degree decimal format (22.44561)
o "08830214" Longitude in degree decimal format (088.30214)
o "009" Speed in Km/Hr
o "290" Angle in radians (2.90)
o "2343" Checksum
o ";" Ending delimiter
• Information packet: $1002 ABC 0000;
o "$" Starting delimiter
o "I" Packet type (I for information packet)
o " ABC " Dumper name
o "0000" I/O pin status of front master device
o ";" Ending delimiter
• Health beacon: $H110010000;
This packet is generated by the master device itself. The interval of this
beacon is 8000 cycles of the OSAL. This beacon is useful to determine
whether the device is disconnected or hanged. This beacon also contains the
status information (High/Low) of the four pins of the device.
o "$" Starting delimiter
o "H" Packet type (H for health beacon)
o "1" Device type (1 for master devices)
o "1" Device position (1 for front device, 2 for back device)
o "001" Dumper ID
o "0000" Status of four channels (Channel_0, ChanneM., Channel_6,
Channel_7) (0 for low, 1 for high)
g. Operating logic when the vehicle is shut down: The master devices need to keep the
lastly broadcasted master packet in memory. Whenever the time from the lastly
sent master packet is much higher than normal time interval, the device should
broadcast the previously saved master packet from memory. The same thing should
be implemented for information packets also.
h. UART / Serial Port Handling Logic: Several threads run inside the software to
perform different operations simultaneously. Each master device is handled by it's
own controller thread. Whenever any data is available for reading from that device,
an event is generated by the COM API and using that event, the software reads the
data bytes and stores in a separate queue buffer inside the software's memory
space. The controller thread of that particular master device retrieves data from the
queue buffer after each 100ms interval, parses the data available inside the buffer,
updates the global data structures and removes the parsed data from the buffer.
2. Proximity Device: Two types of proximity devices are used. All these are low power
802.15.4 devices. The proximity transivers are those which broadcast the proximity
packets as well as receives the proximity packets of other proximity devices. Two
proximity transivers are placed at the front and back side of the vehicle and are
connected to the rugged computer via RS232 ports. Another type of proximity devices
i.e. proximity transmitters are used for only broadcasting. Those devices don't receive
any data. Two proximity transmitters are placed at left and right side of the vehicle.
a. Addressing Scheme: Broadcast mode. The intended receiver address is OxFFFF.
b. Operating Channel: 10
c. Baud Rate: 115200
d. Power consumption: Low power
e. Data broadcast interval: The data broadcast interval of the proximity devices is 4000
cycles of OSAL.
f. Packet structure: Proximity packets are sent via proximity devices.
• Proximity packet: $P004;
o "$" Starting delimiter
o "P" Packet type (P for proximity packet)
o "004" Dumper ID (3 digit numeric identifier from 1 up to 999)
o ";" Ending delimiter
• Health beacon: $H210010000;
This packet is generated by the proximity transiver itself. It is useful to
determine when the transiver device is disconnected or hanged.
o "$" Starting delimiter
o "H" Packet type (H for health beacon)
o "2" Device type (2 for proximity transivers)
o "1" Device position (1 for front, 2 for back)
o "001" Dumper ID
o "0000" Not used
g. Operating logic when the vehicle is shut down: All the master devices always
broadcast proximity packets so that other vehicles can be alerted.
3. Digital Compass: The digital compass is used for getting the heading angle of the vehicle.
The performance of the digital compass can be hampered by magnetic fields generated
by iron materials and heavy vibration. Several techniques are used to improve the
performance of the digital compass in static / dynamic conditions.
a. Baud Rate: 115200
b. Data Format: $HCHDT
c. Data Rate: 20 Hz
d. Calibration: Factory settings
e. Sampling interval: 100 ms
Filtering technique: At dynamic conditions due to heavy vibration, erroneous data can
be generated by the digital compass. A filtration algorithm is used to filter the data
received from the compass. The output of the filtration technique (i.e. Final mean
average angle) is stored as a global variable and is required for further processing. The
controller thread dedicated for the compass, periodically parses all the data available in
the input buffer in 100ms interval and stores the angle values with timestamp
information in a key-value type queue buffer. It keeps the queue buffer always updated
with all the latest data received in last 800ms and the data older than 800ms are
removed from the queue. After adding all the new data, an average of all the angles
available in the queue buffer is calculated and the deviation of each angle inside the
queue buffer w.r.t. the average angle is calculated. Those whose deviation is higher than
PI/3 are removed from the queue buffer and a new average of the remaining angles are
calculated. The mean of this new average with previous global final mean average angle
is the current final mean average angle which is stored as global final mean average
angle. The global data structures are also updated by this angle.
4. Radar: The radars are connected to the rugged computer using CAN-USB converter via serial
port. The CAN API is used to communicate to the radar. The API provides different ports (i.e.
PCANJJSBBUS1, PCAN_USBBUS2) to access the data. The user need to mention these ports in
the configuration dialog to distinguish between front and back side radar. The ports can be
obtained by connecting the radars one by one and running the sample Java application provided
with the PCAN hardware.
a. Address: 12h
b. Baud Rate: PCAN_BAUD_250K
c. Type: PCAN_TYPE_NONE
d. Hardware configuration:
5. Client Application: The client application runs on a rugged computer. All the devices are
connected to the rugged computer via USB / RS232 ports.
a. Resolution: This software works in almost all resolutions. But the preferred resolution is
1024 X 768.
b. GPS calibration: A square area at the left portion of the screen is used for GPS calibration.
For w X h resolution, the leftmost h X h area is calibrated into GPS coordinates. And the
rightmost (w-h) X h area is used for displaying other status panels. The self dumper is always
placed at the center of the map area. Inside the map area, a circle of radius h*9/20 pixels is
assigned as a circle with 100m radius. Using this assumption the meters per screen pixel
ratio is calculated. Five concentric circles with radius 20m, 40m, 60m, 80m and 100m are
drawn based on the center of the map area. The self dumper is placed at the map area such
a way that the center of the front side of the self dumper is placed at the center of the map
area and the direction is always towards the top of the screen. The four corner points of the
self dumper is obtained based on the length and breath of the dumper and pixel per meter
ratio of the calibrated screen. To draw a foreign dumper w.r.t. self dumper, at first the
distance between the two dumpers are calculated based on their GPS coordinates. The
azimuth of the foreign dumper w.r.t. self dumper is calculated using standard formula.
Based on this azimuth, self bearing angle and distance information, the center point of the
foreign dumper is obtained. The orientation angle of the foreign dumper is calculated based
on it's relative heading angle. Based on the center coordinate and relative heading angle,
the four corner points of the foreign dumper is calculated and drawn on screen. Because the
relative position and orientation of all the other dumpers and small vehicles directly depend
upon self bearing angle, some change in the self bearing angle makes an angular
displacement of the whole reference frame. Due to heavy vibration at dynamic condition,
angular movement of the reference frame happens rapidly. This effect can be minimized by
smoothening the change in compass output using proper algorithms.
c. Screen refreshing technique: The software contains some global data structures which it
updates regularly by the data received from the RS232 / USB ports. The screen update
routine is called by the application controller thread periodically at about 200ms interval.
The screen update routine uses the global data structures for drawing the objects on the
screen.
d. Safety contour creation: A safe zone is calculated surrounding each dumper's body. If any
other dumper's safety contour overlaps with it's own, an audio visual alarm is generated to
warn the driver about the situation. And the driver can see the alarming object on the
screen. The safety contour is basically a polygon surrounding dumper's actual region. The
size and shape of the contour varies depending on dumper's speed and other parameters
like the load the dumper is carrying.
e. Delay handling & smoothening algorithm: The GPS receiver provides lat-lng coordinates at
around 1 second interval. Due to this, rapid shifting of the foreign vehicles are visible in the
Ul. To minimize this effect, the intermediate positions at the intermediate time slice are
calculated using an algorithm.
If the reception time of two consecutive gps coordinates (X1,Y1) and (X2,Y2) are t1, t2 and
the speeds are u, v and the bearing angles are a, b respectively then
Acceleration f = (v-u)/(t2-t1)
Bearing change rate k = (b-a)/(t2-t1)
Then c1 time interval after time t2 the next point distance will be
S = vt2 + 1/2*f*t2*t2
And this distance is covered using bearing angle
B = b+t2*k
Now the coordinate of the point (x21,y21) can be calculated using coordinate (X2,Y2),
distance S and bearing B using standard formula
To calculate point (x22,y22) the distance and bearing is calculated from coordinate (x21,y21)
To calculate point (x23,y23) the distance and bearing is calculated from coordinate (x22,y22)
f. Proximity alert generation: The proximity transivers always listen for proximity packets
broadcasted by proximity transmitters as well as proximity transivers of other vehicles. If
any such beacon of foreign vehicle is received by self proximity transivers, they send it to
the software via RS232 ports. The software makes that particular proximity transiver red. In
case the self vehicle is moving an audio alarm is raised to notify the driver about present
situation.
g. Local data storage: The software can be configured to store all the self and foreign data in a
log file. The name of the log file is always same to the present date.
BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1:
Visualization to the driver with relative positioning of the vehicles nearby within a radius of 250 meters;
Audio visual warning on early and proximity alarm conditions with overlapping safety coordinates.
WE CLAIM:
1. A real-time dumper collision avoidance system that uses Global Positioning System and digital
compass to compute virtual safety shielding around dumpers.
2. IEEE 802.15.4 based wireless technology to exchange of position information of other dumpers in
the vicinity to get emergency alert, when a dumper's safety shield is found to be compromised with
any other operating vehicles in its close proximity
3. Multiple Radio Frequency based proximity warning to get alert on impending collision with other
dumpers so that driver can control his vehicle movement
4. Integration of accurate object detection technology using Radar to offer protection during back-up
and start up of vehicle to avoid accident with other small vehicles (like jeeps & cars), field workers
and fixed hazards
5. On-board rugged display to assist the drivers with map based visualization of the movement of
other dumpers in its vicinity that helps the driver to navigate freely and issues audible alarms to
driver as and when a probable collision situation is envisaged
6. Complex algorithm to minimize the false alarm generation under permissible conditions to avoid
distraction of the dumper operators.

The present invention is in the field of safety of the operational dumpers/other huge sized vehicles and
their drivers in the open pit mines. The system allows the drivers to safely navigate the vehicle avoiding
collision with other vehicles/human beings/objects in the vicinity. Harsh mining conditions in the open
pit mines pose a great challenge in maintaining safety in operation. The heavy vehicles operating in the
open pit mines need to maneuver carefully in order to avoid mishap. Therefore, the problem of safely
carrying on the production and operation in open cast mine without any fatal accident, ensuring
workers' safety and safeguarding the costly mining equipments against collision is identified as a major
challenge in open-cast mines. The Dumper Collision Avoidance System is capable of assisting the drivers
with the visual information and audible warning about the other dumpers and objects in its vicinity
during its course of movement. This helps them to navigate their dumpers safely inside the mine
avoiding the risk of collisions with other vehicles, fixed hazards and workers in its vicinity in poor
operating environment. The functionalities of the system are:
• Visualization of other dumpers in the vicinity (using inter-dumper wireless communication network)
to generate early warning based on GPS and orientation & heading analyzer
• Radio Frequency based audio-visual proximity warning
• Radar based static & mobile object detection (like jeeps, cars and field workers) and alert generation
for drivers' navigational assistance
• Camera based rear viewer on dumper reversal
• Small Vehicle Detection Unit for the dumpers to detect presence of a small vehicle