Degrees Of Freedom
The term 'degrees of freedom' refers to number of different ways an appendage can pivot. Robotic arms exemplifies the importance of degrees of freedom. For instance, they are particularly valuable in the handling of materials. For instance,the ability of a robotic arm to rotate and pivot is valuable in performing paint jobs on cars as they twist and bend to precisely apply the amount of paint needed for each component. A standard robotic arm is made up of seven metal segments has six joints and each joint us pivoted by a stepping motor or by a hydraulic or pneumatic motor if the joint is too big. These motors move in exact increments so that the arm is moved precisely. A typical robotic arm has six degrees of freedom,corresponding to the joints: base of arm (rotation), base of arm pivotedbending of elbows,wrist moving up or down, wrist moving left or right, wrist (rotation). Depending on the level sophistication, some robotic arms will rotate full while others will only move in one direction...
Input hardware used in robotics
To input data into a robotic system, there are typically five types of hardware that will be used.
1)Digital camera
2)Keyboard
3)Light pen
4)Mouse
5)Microphone
Sensors
Sensors are devices that measures and converts input from the environment into a signal that can be communicated to a control system. Each form of data input requires a different type of sensor.
Sensor Name
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Description
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Examples of use
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Potential Issues
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Thermostat
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A switch that opens at a set temperature and stays open while the temperature remains at that level or higher: when the temperature falls below that level, the switch closes. Most of the thermostats consist of a bimetallic coil near the lever that uncoils when heated and coils when cooled to maintain a certain temp.
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Hot-Water Services
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Not as accurate and as responsive as the other sensors
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Thermistor
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Measures temperature continually as resistance: When temperature increases,resistance drops
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Air Conditioners
Microwave
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'' (Similar to thermostat)
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Semiconductor
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Uses semiconductors(sensor materials with poor electrical properties) to measure temperature
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Video Cassette Recorders
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Expensive and needs to have a power source to operate
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Light
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Detects changes in the level of light. Can read barcodes as the colour of the bars change from black and white. These changes then will be converted into digital form
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Bar Code Scanner.
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Hard to use standard light sensors to convert complicated images into digital forms.
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Position
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2 types: Contact Sensor and a more complex version.
Contact Sensor- a switch that goes on and off when the machine comes in and out of contact with an object. Complex Position Sensor: Decide how far away an object was from a machine through the use of light sensor. A light source projects itself ahead of the machine and the level of light reflection would then be picked up by the light sensor. When the light intensity reaches a certain level, switch opens up. |
Security System in a building/cargo system
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Expensive, complex and it's hard for the light sensor if the object is transparent(refraction)
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Potentiometers
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Used to determine rotation . They work on electrical resistance and the meter shows the amount of voltage at a particular point.
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Audio Control
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None so far.
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Sonar
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Determine position using high frequency sound waves that bounces off objects...
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Submarine
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Problems with privacy
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4: Actuator vs Sensor
Sensors are devices that measures and converts input from the environment into a signal that can be communicated to a control system.A sensor, such as a sonar,is used by a robot to help a robot determine position using sound waves.Actuators on the other hand,are specialised hardware devices that output a response according to the instructions given by the control system. Each actuator does a different task, from switching a device on or off to complex motors. They work on power: electrical,hydraulic(oil under pressure) or pneumatic air under pressure). Forms of actuators include solenoids,steeping motors and pneumatics.
5:Types of Outputs
Output devices
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Description and main feature
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Advantage
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Disadvantage
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Speakers
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controlled through volume; this will be available to a wide range of people.
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Normal speech rather than synthesised speech is possible with a speaker
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Require extra hardware e.g. sound cards.
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Display (CRT or LCD)
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A visual display unit that displays content through a screen. Wide range of uses..
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No waste of paper, can be interactive or display animations e.g. touch screen
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No Hard Copy in case of data loss..
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Solenoids
(an actuator)
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An electromagnet used to move an arm or plunger through small movement as electric currents pass through it. This magnet can push or pull an object... Uses incl. small solenoid is used to push a rod to connect to the smarter motor drive car when the ignition key is turned on to start a car.
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Ease of access, can move heavy objects with ease
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Wont work if there's no electric current.
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Stepping motors
(an actuator)
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An electromagnet that counts the rotations of a motor around a spindle to measure position as the shaft of the motor turns in small steps. E.g. of its use: HARD DISK DRIVE, a hard disk drive uses a stepping motor to track the right position on the platter and track of the disk to read-write head .
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Accurate.
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Complex. Same problem with hard disks. If it's damaged e.g. dropped from a height, the magnet would disconnect and there would be data corruption
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Position
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Position Sensitive Device. A device that can measure a position of a light spot in 1 or 2D surfaces. They work according to two different principles: One which uses an isotropic sensor surface structure that supplies continuous position data ;Second uses discrete sensors for discrete data ( continuous data is an infinite no of values, usually physical measurement; but discrete only has a fixed no of values). A lot of uses, one of them is measuring vibration measurements for bridges and railroad tracks.
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Measures with great speed and accuracy
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One Dimension Devices' results are sometimes unreliable,though very rarely due to the high stress created by the indium oxide gate.
Expensive and requires skill. |
Potentiometers
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An instrument that acts as a voltage divider. Common used as a variable resistor in electronic devices such as TVs,Audio control..
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Inexpensive,often made out of Graphite. Robots could use potentiometers as a position feedback device to create a closed loop control.
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Can't handle significant power,since the power dissipated in the potentiometer is comparable to the power in the controlled load.
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Sonar
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Acronym for Sound Navigation and Ranging. Used to navigate ,communicate or detect objects by listening for the sound made by objects or by emitting pulses of sounds and listening for echoes,depending whether its passive sonar or active sonar.
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A way of perceiving without the need for vision. Lots of uses, as a sonar can detect objects,their sizes and their mass.
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Might have privacy concerns and active sonar can lead to mass stranding of marine mammals.. As marine mammals are often highly sensitive to the mid-high frequency waves of active sonar
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Primary Storage
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| RAM |
A computer stores data using several different methods, that's why there's different levels of data storage,also referred as Primary and Secondary storage. Primary storage refers to specifically the components on a motherboard. An example of an primary storage device would be RAM or random access memory. It is considered primary storage,since it stores data that is directly accessible by the computer's CPU with minimal delay. Because RAM is connected directly via the memory bus to the CPU, the CPU can access the data very quickly and for this reason, RAM is used to store data loaded by active programs and the operating system.Another example of a Primary Storage device would be the ROM, or read only memory.
Secondary Storage
 |
| USB |
Also known as auxiliary storage, it differs from primary storage because it is not directly accessible to the CPU. The computer uses I/O channels to access secondary storage and transfers data using intermediate area in primary storage. Secondary storages does not lose data when the devices is powered down. The size of the secondary storage determines the ability of a computer system to store data for future use. Examples include hard disks,DVDs and flash drives.
Motherboard.
A-PCI slot : Place where you put your PCI, a local communication system for attaching hardware devices in a computer.
B-PCI-E 16X Slot : Used for a graphics card. With two slots,like the one in this diagram, two graphics card can be run in SLI.
C-PCI-E 1x Slot: Used for expansion cards such as Sound Cards or Ethernet Cards. Each lane carries 250MB/s compared to the PCI slots,which has a carrying capacity of 133 MB/s.
D-Northbridge:Allows communication between the CPU adn the system memory and PCI-E slots.
E-ATX 12V 2X and 4 Pin Power Connection:One of two power connections that supply power to the motherboard.
F-CPU-Fan Connection: Where the CPU fan will connect. Using this connection over one from your power supply allows the motherboard to control the speed of the fan based on the CPU temperature.
G-Socket Where the CPU will plug in. Orange brack thiat is surrounding it is used for high end heat sinks.Helps to support the weight of the heat sink.
H-Memory Slots Slots for the RAM. Most boards will have 4 slots. The colour coding illustrated on the motherboard diagram is used to match up RAM for Dual Channel.Doing so will give your memory a speed boost
I-ATX Power Connector : Second of two power connections. THhis is the main power connection for the motherboard and comes from the Power Supply.
J-IDE Connection: Intergrated Drive Electronics is the connection for your hard drive or CD/ DVD drive.
K-Southbridge : This is the controller for components such as the PCI slots, onboard audio and USB connections
L-SATA Connections: These connections will be used hard drives and CD/DVD drives. Preferred over the IDE.
M-Front Panel Connections : Where you hook in the connections from your case. mostly different lights on your case,such as power on,hard drive...
N-FDD Connection : Floppy Disk Controller. Where you hook floppy disks up...
O-External USB Connections: Where external USB connections will be plugged in
P-CMOS battery: Motherboard's battery. Used to allow the CMOS to keep its settings
