Presented By
Madan Gopal Rao .C

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Development of a Vehicle Control Unit of a Drive By Wire system for conversion of a BMP2 Tank into a teleoperated & autonomous vehicle

Introduction
Unmanned Vehicles or Robots increase the effectiveness of the armed forces by reducing the exposure of personal to dangerous and hazardous conditions.
Hence Conversion of the BMP2 into an autonomous un-manned teleoperated vehicle.
What is the difference between teleoperated and autonomous?
Teleoperated : Indicates operation of a machine by a human from a distance. It is similar in meaning to the phrase “remote control”.
Autonomous : Indicates that a machine can perform desired tasks in unstructured environments without continuous human guidance.
The BMP2 tank in this project will be completely Teleoperated and will have some degree of Autonomy.
The Crux of the project depends on development of the Drive By Wire system for the BMP2.
Development of the Vehicle Control Unit.
BMP 2
Second Generation, amphibious infantry vehicle introduced in the late 1980s by the Soviet Union .
By the year 1999 about 90% of the complete vehicle and its associated systems were being manufactured in India.
The Indian variant is called the BMP2 ‘Sarath’.
Drive By Wire
A technology known as ‘Drive-By-Wire’ ,also called ‘X-by-Wire’ or simply ‘by-wire’.
Full authority , electronic drive control system.
Navigation of the unmanned vehicle is done by a human operator from the base.
DBW in the BMP2
Applications
The various applications of the system under development are:
The unmanned vehicle have a potential as a effective force multiplier in future warfare.
These autonomous vehicles are used for reconnaissance missions at war fronts.
These autonomous vehicles are used in the cases of surveillance and mine detection system scenarios.
Can be used to detect nuclear, chemical , biological weapons without causing harm to the personal.
Vehicle Control Unit
The electronic vehicle control unit is the heart of the DBW system.
The vehicle control unit will initialize and synchronize with all the vehicle navigation parameters.
It receives commands from the base station processes the command and passes the command to the appropriate MCU.
It has the intelligence of processors and FPGA for processing of the commands.
Continued..
VCU Hardware
Methodology used :
Study of pin configuration and the optimal operational features of each component to be interfaced.
Creation of libraries of the various components using Orcad capture CIS tool.
Circuit level design using Orcad 10.3.
The processor board has been purchased from a company ‘Logic PD’ which contains the processor Texas Instruments AM3517 interfaced with the 256 MB DDR2 SD RAM .
Continued..
Features of the TI AM3517 processor :
The processors are based on the ARM Cortex-A8 core tuned for industrial computing applications.
The ARM Cortex-A8 at 500 MHz provides a 4X performance improvement over 300Mhz ARM9 devices.
Connectivity options with high-speed USB 2.0 OTG & Integrated CAN controller supporting local control of sensors and controllers.
The design of the VCU board includes various interfaces such as :
Ethernet interface to the processor.
USB 2.0 & USB OTG interface.
CAN interface from the VCU board to the MCU boards.
Processor interface with the FPGA XILINX XC3S700AN.
NAND flash interface to the FPGA.
Ethernet Interface
The commands from the base to the vehicle are received through the Ethernet and then transmitted to the processor.
The Ethernet PHY is connected to the Ethernet Transceiver which is connecting to the processor.
Ethernet PHY is the physical layer in the OSI model  RJ45 Connector
Ethernet Transceiver is used for serial data to 10-BASE-T/100-BASE-T
conversion  SMSC LAN8710
Continued..
Ethernet interface design using Orcad 10.3 :
USB 2.0 & OTG Interface
The USB 2.0 & USB OTG (On The Go) serial communication devices are required in order to recover the mission data stored in the memory i.e.., NAND Flash.
The USB PHY are connected to a USB transceiver ( SMSC USB3320), which in turn is connected to the processor.
USB 2.0  Operates in High Speed mode  Up to 480 Mbps.
USB OTG  Lets the device connected on either side of the USB cable to
Decide which is the Master device & which is the Slave.
In designing the USB circuits a Voltage buffer along with Power distribution switches has been incorporated to prevent short circuits.
Continued..
USB 2.0 & OTG design using Orcad 10.3 :
CAN Interface
Controller Area Network (CAN) is a vehicle bus standard designed to allow microcontrollers & other devices to communicate with each other with in a vehicle with out the help of a host computer.
The Vehicle Control Unit board communicates with the various Motor Control Unit boards using the CAN bus.
The processor has a High End CAN Controller (HECC) which is interfaced with a CAN Transceiver  ISO1050.
Continued..
Processor Interface with FPGA
Both the processors are interfaced with the FPGA, the FPGA provides the switching operation between the processors.
The processors are interfaced with the FPGA using General Purpose Memory Controllers (GPMC) which are available in the processors.
The GPMC is used to interface external memory devices to the processors.
GPMC uses :
10 bit address lines [GPMC_A(10:1)]
16 bit data lines[GPMC_D(15:0)]
6 Chip select lines[GPMC_nCS(0:6)]
Continued..
Processor & FPGA interface circuit design using Orcad 10.3 :
NAND Flash Interface to FPGA
Two NAND flash each of 4GB each are interfaced to the FPGA i.e.., one for each processor.
The NAND flash are used for storing the feedback data from the Motor Control Units & also for storing the main program that runs in the VCU.
These NAND flash devices have been manufactured by a company ‘Micron’ & can work in Synchronous as well as Asynchronous modes.
In our module we have configured it to work in Asynchronous mode.
Continued..
The NAND Flash libraries created using Orcad 10.3 :
Continued..
Some more serial data interfaces :
I²C Bus ( Inter Integrated Circuits Bus)
UART (Universal Asynchronous Receiver Transmitter)
McBSP (Multi channel Buffered serial port)
SPI Bus (Serial Peripheral Interface Bus)
These Serial data communication Buses have been interfaced from the processor to the FPGA in order to generalize the board.
VCU Software
The vehicle control unit software receives various commands such as vehicle motion parameters from the base station.
The VCU software processes these information and then gives the validated information to the Motor Control Unit.
The commands from the base station are in JAUS standard i.e...,Joint Architecture For Unmanned System Standard.
Continued..
VCU software flow :
Continued..
P-I-D Implementation
The Proportional-Integral-Derivative (PID) control is used to maintain a set threshold value in a feedback control system.
In the Vehicle Control Unit Software the PID control is used to maintain a set speed level of the vehicle i.e., the threshold value set is the actual value of speed the Vehicle has to maintain.
P-I-D Implementation using Keil
The design of the PID loop has been implemented in C using the Keil micro vision 4 IDE.
The PID loop has been implemented for the speed control of the vehicle.
The Proportional constant (Kp), Integral constant (Ki) and the Derivative constant (Kd) have to be assumed for now, during real time testing they can be calibrated to the correct values.
The Feedback values from the Motor Control Unit are assumed.
In the following simulation results the threshold or the set speed value of the vehicle is 50 Kmph. It is assumed that the Vehicle is travelling in a declining slope.
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 55 Kmph (assumption).
‘rOut’ is the o/p value of the PID loop, this gives the speed that must be added to the speed that is fed back from MCU.
rOut  -10.0195
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 47 Kmph (assumption).
rOut  5.9892
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 52 Kmph (assumpt
rOut  -4.0195
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 49 Kmph (assumption).
rOut  1.9847
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 51 Kmph (assumption).
rOut  -2.0198
The Set point of the vehicle = 50 Kmph.
Feedback value from the MCU = 50 Kmph (assumption).
rOut  -0.0201
Conclusion
Current Status of Project :
Hardware :
The circuit level design of the VCU board has been completed.
The board is currently under fabrication and is expected to be available in the first week of June 2011.
After the board is available it will be subjected to testing.
Software :
First Version of the entire software of the VCU is completed.
The software is awaiting approval from CVRDE.
After the successful completion and Implementation of the entire Drive By Wire system in the BMP2 tank, the teleoperated vehicle will be a major addition in the Indian Army.