Fit Junior Design Essay

2309 words - 10 pages

The main power supply for the bot will be one Traxxas 2872 LiPo battery with three cells. The design for our preliminary bot design requires a supply of 12V and last for at least one continuous trial consuming between 25 and 35A. The LiPo has a 11.6 working voltage, a peak voltage of 14.7 V, and a cutoff voltage of 8.8V. The battery is rated for 100 amps discharging rate and a capacity of 5Ah. The physical dimensions of the battery are 6.1 x 0.98 x 1.8" and weighs 6.29kg.
Internal circuitry
The LiPo battery contains an internal Power Circuit Module (PCM) that protects the battery from being damaged. This particular PCM in this LiPo battery is designed for the ...view middle of the document...

The assumption is that the Lunabot will be continuously moving its motors and actuators; however, the actuators are only active when extracting and depositing lunar regolith. The calculations are to provide a theoretical situation of constant consumption, so the Lunabot will be able to complete two trails continuously with one LiPo battery. The physical design of the Lunabot will be a modular design where the battery is interchangeable in case it needs to be swapped for a fresh one in between trials (added redundancy).
Power Consumption
Another source of points in the competition is reporting power consumption to the judges. To measure the power draw, both current and voltage will be measured. For current, a 50A 10mΩ high side shunt is placed in series with the battery and its load. A differential pair from the shunt connects to the AD8211 high side current integrated circuit (IC). The AD8211 has a linear response over a large range; however, the error grows exponentially as the voltage drop across the shunt decreases (see fig 2). The AD8211 has a fixed gain of 20. The output is connected to an Arduino Uno microcontroller platform. The wires going from the shunt to and from the AD8211 and to the Arduino Uno are shielded to reduce noise. Other extra precautions that have been taken as to reduce noise on the ADC are disconnecting the power from the ADC pins and adding a 0.1uF decoupling capacitor between the AREF pin and ground. A program was written in the Arduino IDE to sample analog pins A0 and A1, however, data throughput was less than optimal. Therefore, the code was rewritten in C which allowed a sampling rate of 5.8kSamples/sec for current and voltage each.
Voltage is measured using a simple voltage divider which consisted of a 10kΩ voltage trimmer potentiometer as the datasheet recommends the source impedance should be 10kΩ or less. To optimize the accuracy, the trimmer is set to output 1V when the battery is fully charged. The ADC reference voltage is selected the on-chip bandgap voltage reference which is 1.1V.

Figure 8: AD8211 Current Shunt Monitor
The baud rate for the ATMega328P microcontroller is set at 250,000 baud. This was chosen for two reasons. Since the clock is set at 16MHz the UART clock prescaler can only be set at powers of 2. The ADC gives accurate readings if and only if the ADC clock is set below 200 KHz. In this case, the ADC prescaler was set to 128, so that the clock ran at 125 KHz. For a 10-bit reading, it takes the ADC 13 clock cycles, thus around 9600 samples. However, each reading is 10-bits and a tag scheme must be implemented to distinguish a voltage reading from a current reading.
1111 11xx xxxx xxxx

1111 10xx xxxx xxxx
A current reading’s first 6-bits are always 0xFC while a voltage reading’s first 6-bits are 0xF8. The total number of bits is now increased to 16 bits for a single sample. To transmit this information over serial, an addition stop bit is needed which bring the total to 17...

Find Another Essay On FIT_Junior_Design

Psychological Egoism Theory Essay

2240 words - 9 pages The theory of psychological egoism is indeed plausible. The meaning of plausible in the context of this paper refers to the validity or the conceivability of the theory in question, to explain the nature and motivation of human behavior (Hinman, 2007). Human actions are motivated by the satisfaction obtained after completing a task that they are involved in. For example, Mother Teresa was satisfied by her benevolent actions and

How Celtic Folkore has Influenced My Family

1587 words - 6 pages Every family has a unique background that influences the way they live and interact with other people. My parents, who emigrated from Ireland to the States with my three brothers in 1989, brought over their own Celtic folklore and traditions that have helped shaped the way our family operates and lives. One aspect of folklore that has helped shape my family dynamic is the Celtic cross—both its background and what role it has played in our lives

Julia Margaret Cameron

1406 words - 6 pages At a time when women were looked upon as being homemakers, wives, mothers and such the late 1850's presented a change in pace for one woman in specific. Photography was discovered in 1826 and soon after the phenomenon of photography was being experimented with and in turn brought new and different ways of photo taking not only as documenting real time, but also conceptualizing a scene in which an image would be taken. Julia Margaret Cameron will

Evaluation of School Improvement

1403 words - 6 pages The evaluation process should be progressive to incorporate overall planning, implement changes, which contribute to success. In order to focus on school climate and norms, the evaluation design must include the students, instructions, and outcomes to improve communication and building-level concerns to be address in this response. School Climate and Social Norms The school principal, other staff leaders, and personnel set the tone and the

Case Study: The Benefits of Animal Testing

1757 words - 7 pages Nine year old Amy has already had a rough start in life. She was born with an abnormal heart that hinders her everyday activities. Amy is unable to keep up with kids her own age because she often tires out easily. As a consequence, she has very little friends and is often alone. Amy is forced to take different medications everyday just to survive. Amy’s life consists of medicine, doctors, and constant hospital visits. However, Amy is due for a

Myth and Magic: Realism in "One Hundred Years of Solitude"

1531 words - 6 pages “He enjoyed his grandmother's unique way of telling stories. No matter how fantastic or improbable her statements, she always delivered them as if they were the irrefutable truth” (Wikipedia, 2011). Experiences are particular instances of one personally encountering or undergoing something and in these moments of time life changes for the best or the worst and memories are formed. These recollections such as riding your first bicycle, going to

Adiponectin: a Novel Indicator of Malnutrition and Inflammation in Hemodialysis Patients

2384 words - 10 pages Objective Protein-Energy malnutrition (PEM) and inflammation are common and overlapping conditions in hemodialysis patients which are associated with increased risk of morbidity and mortality. Adiponectin is an adipocytokine which is exclusively produced by adipose tissue. Few studies in hemodialysis patients have demonstrated that serum levels of adiponectin were significantly higher in malnourished patients compared to well-nourished ones. The

The Congo Free State: A Legacy of Apathy, Exploitation and Brutality

2298 words - 9 pages Between 1885 and 1908, Belgium’s Leopold II ruled Congo, a region in central Africa, as his personal colony, exploiting the resources and inhabitants for his own gain. Leopold allowed and encouraged Europeans and other Westerners to enter Congo and set up companies whose primary purpose was to gather rubber, which was abundant but difficult to get to in the Congo, using the Congolese as the laborers for the Europeans. Rubber gathering in Congo

Selective Exposition in The Lottery, by Shirley Jackson

1073 words - 4 pages Usually when someone hears the word “lottery” the first thing that comes to mind is a large sum of cash that people compete against highly impractical odds to win. Shirley Jackson’s story The Lottery might imply a similar conception based on the title alone, but the story is filled with unknowns never revealing exactly when and where the story takes place, or why the lottery exists; even what the lottery is isn’t revealed until the very end. Yet


1857 words - 7 pages INTRODUCTION I remember when I was a young child; I would always be scared whenever there was a severe storm outside that included thunder and lightning. This was especially true in the hours of darkness, when you could really see the lightning. As I grew older this so-called fear of lightning turned into a fascination for this weather phenomena. One of my most vivid memories of lightning as a young man was when I was flying to Florida, the

Maryland's Ecology and Environment

1130 words - 5 pages Maryland is the 42nd largest state, making it one of the smaller states in America. It is located in the South Atlantic region on the United States eastern seaboard. Prince George's is one of twenty four counties in Maryland. It is also the geographic center of the state. Maryland has a varied climate. The state is home to a variety of different ecosystems. This is also true of Maryland’s environment, which has the Atlantic Ocean on

Similar Essays

When The Bubble Burst Essay

1539 words - 6 pages By the time I arrived state side from my second tour in the Middle East the housing bubble had already burst. I noticed a drastic change in the way that many of my friends and family were living. Several of my friends that worked in real estate had sold their boats and seconds houses. My own stock portfolio had lost a third of its value. My sister and her husband had defaulted on their home mortgage leaving them scrambling for a place to live. I

Phase Diagram Essay

4456 words - 18 pages Introduction: Chemical equilibrium is a crucial topic in Chemistry. To represent and model equilibrium, the thermodynamic concept of Free energy is usually used. For a multi-component system the Gibbs free energy is a function of Pressure, Temperature and quantity (mass, moles) of each component. If one of these parameters is changed, a state change to a more energetically favorable state will occur. This state has the lowest free energy

Revolutionary Work Of Art Essay

1890 words - 8 pages Walter Benjamin emphasizes in his essay, “The Work of Art in the Age of its Technological Reproducibility” that technology used to make an artwork has changed the way it was received, and its “aura”. Aura represents the originality and authenticity of a work of art that has not been reproduced. The Sistine Chapel in the Vatican is an example of a work that has been and truly a beacon of art. It has brought a benefit and enlightenment to the art

Enlightenment Thought In New Zealand Schools

1594 words - 6 pages In this essay I will be looking at how the political and intellectual ideas of the enlightenment have shaped New Zealand Education. I will also be discussing the perennial tension of local control versus central control of education, and how this has been affected by the political and intellectual ideas of the enlightenment. The enlightenment was an intellectual movement, which beginnings of were marked by the Glorious Revolution in Britain