FYP 2 : WEEK 14

Title of activity

- Presentation final year project 2 at foyer TTL.

Objective

- To present the final year project after completion of project.

Content

- All the final year project 2 student will present their projects to be evaluated.
- Two lecturers will evaluate the student project and one student will be evaluated with two lecturers.
- The presentation day is about to explain the ideas of project and how student understand about the project.

FYP 2 : WEEK 13

Title of activity

- Combine all the circuit and install with the robot arm to complete the project.

Objective

- To make intelligent fire fighting system project complete.

Content

- This was a finalize job and combine all circuit and install with the robot arm and test it.
- Microcontroller circuit and sensor circuit will combine with main circuit.
- Make sure all the connection are correct to avoid installation errors.
- After the circuit combine complete, it will installed on robot arm. The circuit will connect to the robot arm motors, alarm/buzzer and motor pump.
- After all that job complete, the project will tested and the project can function normally.

FYP 2 : WEEK 12

Title of activity

- Test all motors, alarm/buzzer and motor pump by using 12 v power supply.

Objective

- To make sure that equipment function normally.

Content

- Connect the 12 v motor left and right with 12 v power supply.
- Turn on the supply and the motor function and arm move left and right in 45 degrees.
- Then, connect the 12 v motor up and down with 12 v power supply.
- Turn on the supply and the motor function and arm move up and down in 45 degrees.
- Now robot arm operate as a plan.
- After that, connect the motor pump to 12 v power supply. The motor pump is put in the plastic box as a water tank and with full water in there.
- Turn on the supply and motor pump function and water through the water hose inside the PVC pipe.

FYP 2 : WEEK 11

Title of activity

- Construct the 18F252 flash microcontroller circuit.

Objective

- This circuit is use to control the main circuit.

Content

- This circuit have one microcontroller and attach with crystal and ceramic transistor.
- This circuit use 5 v input power and one regulator transistor 12 v to 5 v is use to reduced the supply 12 v to 5 v for input power microcontroller.
- The regulator transistor is use because this circuit is take the power from power supply 12 v and we must to invert it to 5 v.
- Circuit has five input and five output. The input is port A and the output is port C.

FYP 2 : WEEK 10

Title of activity

- Construct the main circuit of Intelligent fire fighting system.

Objective

- This circuit is use to contact the robot arm motors, sensor, alarm and motor pump when microcontroller give the signal.

Content

- This circuit have three relays 250v / 12v 5 amp and two relay 125v / 12 v 1 amp.
- Three relays is to contact two motor for robot arm and one motor pump.
- Another two relays is to contact alarm/buzzer and sensor circuit.
- One regulator transistor 12v to 9v is use to reduced the voltage to 9 v for sensor circuit input power.

FYP 2 : WEEK 9

Title of activity

- Construct the LDR sensor circuit

Objective

- This sensor circuit is use to get the sensor function.

Content

- The sensor circuit is use one relay using to contact the circuit when flame is detect by sensor.
- One veriable resistor is use to adjust the sensitivity of sensor to the flame.
- This circuit is supply by 9 V power from main circuit.
- After construct, I test the circuit and it work.
- The minimum for sensitivity sensor is 5 cm from the flame and the maximum for sensitivity sensor detect is 3 meters.

FYP 2 : WEEK 8

Title of activity

- Build the Robot Arm for intelligent fire fighting system project

Objective

- This project are using robot arm to found fire and direct the water on the fire and extinguish it.

Content

- For foot to hold the robot arm is using one stand automatic fan.
- One motor 12 v DC is put at the joint between stand and arm. This motor is function to move the robot arm left and right.
- The robot arm move 45 degrees left and 45 degrees right.

- For the arm is using PVC pipe 16 mm and it was attach with one hose water.

- For the arm movement up and down, one motor 12 v DC is put at the joint between pipe and stand fan.

- The robot arm is move 45 degrees up and 45 degrees down.

FYP 2 : WEEK 7

Title of activity

- FYP briefing at gemilang hall
- Buy the all component at jalan pasar.

Objective

- The briefing is to tell about the progress report and updating blog for final year project 2.
- Find and buy all list component to start make the all circuit for project.

Content

- Briefing at gemilang hall is to reminder the student about the report and blog and tell student the format for report.
- The list of component that used to this intelligent fire fighting project :

-One power supply 110-240 v AC / 12 v DC 120 W 10 A.
-Two 12v DC motor.
-Three JW2SN-DC12V 5 amp 250Vac/ 5 amp 12 Vdc
-Two SCR-12VDC-SH 1 amp 125 Vac/ 1 amp 30 Vdc
-One regulator transistor 12 v to 9 v L7809CV6
-Six diode IN4001 1 amp
-Five on off switch 
-Two push button
-One PVC pipe
-One plastic pipe for water
-One motor pump
-One buzzer for alarm.
-One 18F252 flash microchip
-One crystal 4 Mhz
-Two ceramic capacitor 22 f
-Five transistor PNP 2N3904
-Five transistor NPN C1815
-15 resistor 1K
-One regulator transistor 12v to 5v LM7805

- All this item can found at jalan pasar.

FYP 2 : WEEK 6

Title of activity

- Create the robot arm for intelligent fire fighting.

Objective

- This robot arm is the main purpose for this project and use to extinguish the fire.

Content

- This robot arm is create by stand of automatic fan and pvc pipe.
- The water pipe is attached to the pvc pipe and the water are through out from the pvc pipe.
- For the movement, two 12v Dc motor attached between two joint of pvc pipe and stand of automatic fan.
- One 12v DC motor used to move the robot arm left and right and another 12v DC motor used to move robot arm up and down.

FYP 2 : WEEK 5

Title of activity

- Create the main circuit for motor, sensor and motor pump.

Objective

- To create one circuit for microcontroller to control all the main equipment.

Content

- This circuit I created is for easy to microcontroller to control all the main equipment such as two motor, sensor circuit, alarm, and motor pump.
- In this circuit I use five relay to control all the main equipment.
- Three relay is 250/12v 5 Amp to contact the two motor and one motor pump and another two relay is 125v/12v 1 Amp using to contact alarm/buzzer and sensor circuit.
- The microcontroller is program to control all the relays and the re;ays are contact all the main equipment.

FYP 2 : WEEK 4

Title of activity

- Decide the type of microcontroller to used in project.

Objective

- Used to control the main circuit such a relay, motor, sensor and motor pump.

Content

- This project is use microcontroller 18F252. I use this microchip because this powerful 10 MIPS (100 nanosecond instruction execution) yet easy-to-program (only 77 single word instructions) CMOS FLASH-based 8-bit microcontroller packs Microchip's powerful PIC® architecture into an 28-pin package and is upwards compatible with the PIC16C5X, PIC12CXXX, PIC16CXX and PIC17CXX devices and thus providing a seamless migration path of software code to higher levels of hardware integration. 

- The PIC18F252 features a 'C' compiler friendly development environment, 256 bytes of EEPROM, Self-programming, an ICD, 2 capture/compare/PWM functions, 5 channels of 10-bit Analog-to-Digital (A/D) converter, the synchronous serial port can be configured as either 3-wire Serial Peripheral Interface (SPI™) or the 2-wire Inter-Integrated Circuit (I²C™) bus and Addressable Universal Asynchronous Receiver Transmitter (AUSART).
- All of these features make it ideal for manufacturing equipment, instrumentation and monitoring, data acquisition, power conditioning, environmental monitoring, telecom and consumer audio/video applications.

Features

2 PWM 10-Bit 40 MHz Max. Speed Self Programming ICD

Parameter Name	Value
Program Memory Type	Flash
Program Memory (KB)	32
CPU Speed (MIPS)	10
RAM Bytes	1,536
Data EEPROM (bytes)	256
Digital Communication Peripherals	1-A/E/USART, 1-MSSP(SPI/I2C)
Capture/Compare/PWM Peripherals	2 CCP
Timers	1 x 8-bit, 3 x 16-bit
ADC	5 ch, 10-bit
Temperature Range (C)	-40 to 125
Operating Voltage Range (V)	2 to 5.5
Pin Count	28

reference: http://www.microchip.com

FYP 2 : WEEK 3

Title of activity

- Decide the type of sensor for detect fire in intelligent fire fighting system.

Objective

- Choose the right sensor for the project.

Content

- For this project I decided to use the light dependent resistor ( LDR ) sensor as a fire sensor.
- Light dependent resistors are a vital component in any electric circuit which is to be turned on and off automatically according to the level of ambient light.
- It use to detect the fire flame.

reference : - doctronics.co.uk
                 - electroschematics.com

FYP 2 : WEEK 2

Title of activity

- Decide to use the type of power supply

Objective

- To choose the right power supply for support the intelligent fire fighting system circuit.

Content 

- For this project I use the Power supply 110-240 v AC / 12 v DC 120 W 10 A.
- This power supply is built to take 240 v AC from electrical power and supply electrical load 12 v DC to the circuit.
- The term is most commonly applied to electric power converters that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy (mechanical, chemical, solar) to electrical energy.
- This power supply can support all of component that used for this project.

reference ; en.wikipedia.org/wiki/Power_Supply

FYP 2 : WEEK 1

Title of activity

- Meeting for FYP student at Gemilang Hall.

Objective

- Briefing about the FYP schedule for semester 2.

Content

- We need to start do the finalize FYP for this semester.
- Te meting guiding us on how to enter the FYP website and click on important part. They also alert us about the presentation due date.
- Meting conducted are very useful in order to help and guiding student through the finishing task given. 

Week 14

Title of activity

- Prepare and complete whole part of Chapter 1 until 3 Full Report.

Objective

- To complete the Chapter 1 until 3 Full Report for FYP 1.
- To complete the schedule for this semester.

Content

- Need complete the Chapter 1 until 3 Full Report.
- Chapter 1 until 3 Full Report contains Introduction, Literiture Riview and Methodology.

Week 13

Title of activity

- Prepare and complete whole part for Progress Report.

Objective

- To finalize my progress report for FYP 1.
- To complete the schedule for this semester.

Content

- Need to complete the progress report from when month that start doing the project until the project done.
- Write all the detail of progress project in the progress report.

WEEK 12

Title of activity

- Presentation Day at foyer TTL.

Objective

- To meet other assessors and present my project to make them understand about my project.
- To more understand about our project.

Content

- Before presentation all student must register at dewan gemilang, registration start from 12 pm -
2 pm.
- Present my slide show to two assessors.
- Both of assessors will ask three question after I done my presentation and the question is based on my project.
- Start presentation on 2 pm - 5 pm.
- The presentation will carry 10% marks'
- I get more information and idea that related to this project base on comment from both of assessors give to me during presentation day.
- By doing the presentation, I make myself more confident to do presentation after this.

WEEK 11

Title of activity

- Prepare for presentation day on week 12.

Objective

- To make other people understand about what have we done during that presentation by using slide show.

Content.

- Do and complete slide for project presentation on week 12.
- The presentation slide using laptop.
- Slide show will include information based on project proposal for Intelligent Fire Fighting System such as problem statement, literature review, objective, methodology, block diagram and ghannt chart.
- Slide show must easy and short to understand.
- I need explain to both assessors about my project when they read my slide show.
- I also need to answer a some few question from both of them.
- The whole slide show will conclude what is my project about and the slide will give the assessors more information about my project.

WEEK 10

Title of activity

- 3rd briefing FYP at dewan gemilang.

Objective

- To discuss about presentation day on week 12.

Content

- During the day we need bring our own laptop for presentation slide.
- Presentation FYP 1 will be on 12 April 2012 start 2 pm - 5 pm.
- For the presentation it will carry on 10% mark.
- Two assessors will access me during that day and ask me question base on my project.
- Do slide during the presentation day.
- In slide presentation must have;
1- Introduction.
2- Objective.
3- Literature Review.
4- Methodology.
5- Progress of project.
6- Conclusion.
- The briefing is very useful in order to help and guiding student through the finishing task given.

WEEK 9

Title of activity

- Research on robotic arm.

Objective

- To gain knowledge about robotic arm.

Content

- Do some research and reading to find information about robotic arm.
- A mechanical arm is robotic, usually programmable, with similar functions to a human arm. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement^..
- The links of the manipulator can be considered to form a kinematic chain. The business end of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand.
- The end effector can be designed to perform any desired task such as welding, gripping, spinning etc., depending on the application. For example robot arms in automotive assembly lines perform a variety of tasks such as welding and parts rotation and placement during assembly.
-  Types

• Cartesian robot / Gantry robot: Used for pick and place work, application of sealant, assembly operations, handling machine tools and arc welding. It's a robot whose arm has three prismatic joints, whose axes are coincident with a Cartesian coordinator.
• Cylindrical robot: Used for assembly operations, handling at machine tools, spot welding, and handling at diecasting machines. It's a robot whose axes form a cylindrical coordinate system.
• Spherical robot / Polar robot (such as the Unimate): Used for handling at machine tools, spot welding, diecasting, fettling machines, gas welding and arc welding. It's a robot whose axes form a polar coordinate system.
• SCARA robot: Used for pick and place work, application of sealant, assembly operations and handling machine tools. It's a robot which has two parallel rotary joints to provide compliance in a plane.
• Articulated robot: Used for assembly operations, diecasting, fettling machines, gas welding, arc welding and spray painting. It's a robot whose arm has at least three rotary joints.
• Parallel robot: One use is a mobile platform handling cockpit flight simulators. It's a robot whose arms have concurrent prismatic or rotary joints.
• Anthropomorphic robot: Shaped in a way that resembles a human hand, i.e with independent fingers and thumbs.

- Robotic arms are typically used in industry. Repetitive autonomous robots perform one task repeatedly based upon predetermined movements and specifically located objects. Start and stop commands are determined by position, acceleration, deceleration, distance, and direction. More complex actions are executed based upon sensor processing. If object orientation or position is unknown, arms are often paired with machine vision and artificial intelligence to identify the object and subsequently control the arm.

WEEK 8

Title of activity

- Find objective for project proposal Intelligent Fire Fighting System.

Objective

- To find the statements of the purpose / aim of the project.

Content

- A concise and clear outline of the aims that the researcher want to achieve through the project that is fire fighting system.
- The research study intends to plug the research gap and will demonstrate the intelligent fire fighting system.
- To build and design intelligent fire fighting system that can be access to anywhere in the building.
- To know and learn about robotic arm and temperature sensor. 
- To develop a new fire fighting so that our country or world can use it as a new source to fight the fire.

WEEK 7

Title of activity

- Research on sensor

Objective

- To find the suitable sensor for Intelligent Fire Fighting System.

Content

- Do some research in internet to find about temperature sensor.
- Study and understand the function of temperature sensor.
- Type K (chromel{90 percent nickel and 10 percent chromium}–alumel)(Alumel consisting of 95% nickel, 2% manganese, 2% aluminium and 1% silicon) is the most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C, chromel positive relative to alumel. It is inexpensive, and a wide variety of probes are available in its −200 °C to +1350 °C / -328 °F to +2462 °F range. Type K was specified at a time when metallurgy was less advanced than it is today, and consequently characteristics may vary considerably between samples. One of the constituent metals, nickel, is magnetic; a characteristic of thermocouples made with magnetic material is that they undergo a deviation in output when the material reaches its Curie point; this occurs for type K thermocouples at around 350 °C .
-  Applications of Type K thermocouples are used for measurements in many different types of environments such as water, mild chemical solutions, gases and dry areas. Engines, oil heaters and boilers are examples of places where they may be found. They are used as thermometers in hospitals and the food industry.
-  The problems may be minimized by using them within the recommended temperatures and environments. Careful calibration, installing them with the proper connectors and wires, and using compensation circuits also serve as aids. K types constructed to reduce the errors include those that are well insulated, pre-aged or are annealed above their operating temperatures. Some users also take care to replace them often. Others switch to type N, which was specifically constructed to be an improvement over K.

WEEK 6

Title of activity

- Continue progress report with do research on methodology parts.

Objective 


- To description on the opproach meterials and produce used identification on the limitations range of validity and assumptions employed.

Content

- This section contains an overall description of the research approach meterials and procedures.

- The diagram in figure above shows the process overall system that is capable of the Intelligent Fire Fighting System.
- The controller unit is based on micro controller. It controls all the blocks. The unit has a thermocouples to sense the different temperatures, which are fixed in circular path at equal 45 degree, in up and down positions.
- The thermocouple sensors are connected to signal conditioning unit. The sensor produces
low voltage signals (in terms of few milli-volts), which cannot be measured by ADC. Therefore
the weak signals are amplified to 0-5v level by signal conditioner unit. Maybe I'm using ‘K’ type
thermocouple, which has low non-linearity error.
- The output of the signal conditioner is fed to the analog to digital converter (ADC). The ADC has capable of measuring 8 channels and the resolution of 8 bits. The 8 channels are
used to measure the room temperature at different points. One 5-digit seven-segment display
is used to indicate channel No. & temperature.
- A stepper motors drives the robotic arm. One stepper motor is used to rotate the water gun in circular motion and the next one is for to move vertically.
-

WEEK 5

Title of activity

- Do research and produce benefits and contribution on project proposal.

Objective

- To find information that connected to proposed project for benefits and contribution.

Content

Firefighters' goals are to save life, property and the environment. A fire can rapidly spread and endanger many lives; however, with modern firefighting techniques, catastrophe is usually, but not always, avoided. To prevent fires from starting, a firefighter's duties include public education and conducting fire inspections.

Because firefighters are often the first responders to people in critical conditions, firefighters provide many other valuable services to the community they serve, such as:

• Emergency medical services, as technicians or as licensed paramedics, staffing ambulances;
• Hazardous materials mitigation (HAZMAT);
• Vehicle Rescue/Extrication;
• Search and rescue;
• Community disaster support.
• Fire Risk Assessments

Additionally, firefighters also provide service in specialized fields, such as:

A hose team training to fight an aircraft fire aboard a US aircraft carrier, 2006.

• Aircraft/airport rescue;
• Wildland fire suppression;
• Shipboard and military fire and rescue;
• Tactical paramedic support ("SWAT medics");
• Tool hoisting;
• High Angle Rope Rescue;
• Swiftwater Rescue.

In the US, firefighters also serve the Federal Emergency Management Agency (FEMA) as urban search and rescue (USAR) team members.

WEEK 4

Title of activity

- Do research and produce introduction and problem statement on project proposal.

Objective

- To find information that connected to proposed project for introduction and problem statement.

Content

- For introduction part is about background of study and project/research areas.
- For problem statement need to identification of the research problem.
- The introduction should be at a level that make it easy to understand for readers.
- For introduction, this proposal describes an effort to produce the fire fighting system that is suitable for all application.
- For problem statement, I find that  the issue is every time there is fire mostly firefighters did not have time to rescue victims in the building. so, this robot is intended to give assistance to remove the little wag in the building while waiting firefighters coming.

WEEK 3

Title of activity

- Research on proposed project.
- Produce Ghantt Chart.

Objective

- To find information that connected to proposed project.
- To produce Ghantt Chart that indicates details on how the project will bw conducted.

Content

- Search in the internet information that related to this project.
- Produce Ghantt Chart in microsorf excel.
- For Ghantt Chart is planning the miles tone and schedule the project discussion on posibble challenges.
- I find the several type of robot arm and their details and I need time to precisely choose the details to this project.
- I also find some proposal project that has been done by previous people.
- Ghantt Chart indicates stages of  proposed project and set deadline in completing each stage of the project.
- I need more time and find some information that related to this project. Before dive deeper, first must find more information about robot arm and how it works.
- By following the ghantt chart I can set the deadlines in completing task given.

WEEK 2

Title of activity

- Meting for FYP student at Gemilang Hall on Thursday.

Objective

- To finalize our project title for FYP.
- To exposed to FYP student the procedure of FYP.

Content

- We need to choose one of the project title listed and the title must be verified by our supervisor.
- Meting conduct by Sir Zulkhairi at Gemilang Hall and the meting is for exposing to FYP student about the procedure such as register student name at RPS and to create a blog.
- After doing research and having some discussion with my supervisor, I finally decide to select project title that is INTELLIGENT FIRE-FIGHTING SYSTEM.
- Te meting guiding us on how to enter the FYP website and click on important part. They also alert us about the proposal due date.
- Meting conducted are very useful in order to help and guiding student through the finishing task given. 

WEEK 1

Title of activity

- Choose the title at RPS and find the supervisor that can help guiding us for FYP.
- Research on project title that suitable for FYP.

Objective

- To find the supervisor among lecturer at any section.
- To research on suitable project title for FYP.

Content

- We are regaired to find supervisor that can guiding us from beginning ( FYP 1) until the project completely finished (FYP 2).
- From the short listed project title that been prepared by RPS, we need to choose several topic and doing research.
- Lecturer that be my supervisor is Sir. Syamsul Adlan Bin Mahrim from Department of Telecommunication.
- We stant doing research from the internet on some of the project listed taht is Intelligent Fire-Fighting System that use Robot Arm for the robot and heat sensor to detect fire.
- Research is still going on.

Presentation Slide Show For Final Year Project

Research: Robotic Arm

The robot arm is probably the most mathematically complex robot you could ever build. As such, this tutorial can't tell you everything you need to know. Instead, I will cut to the chase and talk about the bare minimum you need to know to build an effective robot arm. 


Degrees of Freedom (DOF) 
The degrees of freedom, or DOF, is a very important term to understand. Each degree of freedom is a joint on the arm, a place where it can bend or rotate or translate. You can typically identify the number of degrees of freedom by the number of actuators on the robot arm. Now this is very important - when building a robot arm you want as few degrees of freedom allowed for your application!!! Why? Because each degree requires a motor, often an encoder, and exponentially complicated algorithms and cost. 


Denavit-Hartenberg (DH) Convention 
The Robot Arm Free Body Diagram (FBD) 

The Denavit-Hartenberg (DH) Convention is the accepted method of drawing robot arms in FBD's. There are only two motions a joint could make: translate and rotate. There are only three axes this could happen on: x, y, and z (out of plane). Below I will show a few robot arms, and then draw a FBD next to it, to demonstrate the DOF relationships and symbols. Note that I did not count the DOF on the gripper (otherwise known as the end effector). The gripper is often complex with multiple DOF, so for simplicity it is treated as separate in basic robot arm design. 4 DOF Robot Arm, three are out of plane: 3 DOF Robot Arm, with a translation joint: 5 DOF Robot Arm: Notice between each DOF there is a linkage of some particular length. Sometimes a joint can have multiple DOF in the same location. An example would be the human shoulder. The shoulder actually has three coincident DOF. If you were to mathematically represent this, you would just say link length = 0.   Also note that a DOF has its limitations, known as the configuration space. Not all joints can swivel 360 degrees! A joint has some max angle restriction. For example, no human joint can rotate more than about 200 degrees. Limitations could be from wire wrapping, actuator capabilities, servo max angle, etc. It is a good idea to label each link length and joint max angle on the FBD. (image credit: Roble.info) Your robot arm can also be on a mobile base, adding additional DOF. If the wheeled robot can rotate, that is a rotation joint, if it can move forward, then that is a translational joint. This mobile manipulator robot is an example of a 1 DOF arm on a 2 DOF robot (3 DOF total). Robot Workspace The robot workspace (sometimes known as reachable space) is all places that the end effector (gripper) can reach. The workspace is dependent on the DOF angle/translation limitations, the arm link lengths, the angle at which something must be picked up at, etc. The workspace is highly dependent on the robot configuration. Since there are many possible configurations for your robot arm, from now on we will only talk about the one shown below. I chose this 3 DOF configuration because it is simple, yet isnt limiting in ability. Now lets assume that all joints rotate a maximum of 180 degrees, because mostservo motors cannot exceed that amount. To determine the workspace, trace all locations that the end effector can reach as in the image below. Now rotating that by the base joint another 180 degrees to get 3D, we have this workspace image. Remember that because it uses servos, all joints are limited to a max of 180 degrees. This creates a workspace of a shelled semi-sphere (its a shape because I said so). If you change the link lengths you can get very different sizes of workspaces, but this would be the general shape. Any location outside of this space is a location the arm cant reach. If there are objects in the way of the arm, the workspace can get even more complicated. Here are a few more robot workspace examples:   Cartesian Gantry Robot Arm   Cylindrical Robot Arm   Spherical Robot Arm   Scara Robot Arm   Articulated Robot Arm Mobile Manipulators A moving robot with a robot arm is a sub-class of robotic arms. They work just like other robotic arms, but the DOF of the vehicle is added to the DOF of the arm. If say you have a differential drive robot (2 DOF) with a robot arm (5 DOF) attached (see yellow robot below), that would give the robot arm a total sum of 7 DOF. What do you think the workspace on this type of robot would be? Force Calculations of Joints This is where this tutorial starts getting heavy with math. Before even continuing, I strongly recommend you read the mechanical engineering tutorials for statics anddynamics. This will give you a fundamental understanding of moment armcalculations. The point of doing force calculations is for motor selection. You must make sure that the motor you choose can not only support the weight of the robot arm, but also what the robot arm will carry (the blue ball in the image below). The first step is to label your FBD, with the robot arm stretched out to its maximum length.

Choose these parameters: weight of each linkage weight of each joint weight of object to lift length of each linkage

Next you do a moment arm calculation, multiplying downward force times the linkage lengths. This calculation must be done for each lifting actuator. This particular design has just two DOF that requires lifting, and the center of mass of each linkage is assumed to be Length/2. Torque About Joint 1:
M1 = L1/2 * W1 + L1 * W4 + (L1 + L2/2) * W2 + (L1 + L3) * W3
Torque About Joint 2:
M2 = L2/2 * W2 + L3 * W3
As you can see, for each DOF you add the math gets more complicated, and the joint weights get heavier. You will also see that shorter arm lengths allow for smaller torque requirements.

Too lazy to calculate forces and torques yourself? Try my robot arm calculatorto do the math for you.

Forward Kinematics Forward kinematics is the method for determining the orientation and position of the end effector, given the joint angles and link lengths of the robot arm. To calculate forward kinematics, all you need is highschool trig and algebra. For our robot arm example, here we calculate end effector location with given joint angles and link lengths. To make visualization easier for you, I drew blue triangles and labeled the angles. Assume that the base is located at x=0 and y=0. The first step would be to locate x and y of each joint. Joint 0 (with x and y at base equaling 0):
x0 = 0 y0 = L0
Joint 1 (with x and y at J1 equaling 0):
cos(psi) = x1/L1 => x1 = L1*cos(psi) sin(psi) = y1/L1 => y1 = L1*sin(psi)
Joint 2 (with x and y at J2 equaling 0):
sin(theta) = x2/L2 => x2 = L2*sin(theta) cos(theta) = y2/L2 => y2 = L2*cos(theta)
End Effector Location (make sure your signs are correct):
x0 + x1 + x2, or 0 + L1*cos(psi) + L2*sin(theta) y0 + y1 + y2, or L0 + L1*sin(psi) + L2*cos(theta) z equals alpha, in cylindrical coordinates
The angle of the end effector, in this example, is equal to theta + psi.Too lazy to calculate forward kinematics yourself? Check out my Robot Arm Designer v1 in excel. Inverse Kinematics Inverse kinematics is the opposite of forward kinematics. This is when you have a desired end effector position, but need to know the joint angles required to achieve it. The robot sees a kitten and wants to grab it, what angles should each joint go to? Although way more useful than forward kinematics, this calculation is much more complicated too. As such, I will not show you how to derive the equation based on your robot arm configuration. Instead, I will just give you the equations for our specific robot design:
psi = arccos((x^2 + y^2 - L1^2 - L2^2) / (2 * L1 * L2)) theta = arcsin((y * (L1 + L2 * c2) - x * L2 * s2) / (x^2 + y^2)) where c2 = (x^2 + y^2 - L1^2 - L2^2) / (2 * L1 * L2); and s2 = sqrt(1 - c2^2);
So what makes inverse kinematics so hard? Well, other than the fact that it involvesnon-linear simultaneous equations, there are other reasons too. First, there is the very likely possibility of multiple, sometimes infinite, number of solutions (as shown below). How would your arm choose which is optimal, based on torques, previous arm position, gripping angle, etc.? There is the possibility of zero solutions. Maybe the location is outside the workspace, or maybe the point within the workspace must be gripped at an impossible angle. Singularities, a place of infinite acceleration, can blow up equations and/or leave motors lagging behind (motors cant achieve infinite acceleration).And lastly, exponential equations take forever to calculate on a microcontroller. No point in having advanced equations on a processor that cant keep up. Too lazy to calculate inverse kinematics yourself? Check out my Robot Arm Designer v1 in excel. Motion Planning Motion planning on a robot arm is fairly complex so I will just give you the basics. Suppose your robot arm has objects within its workspace, how does the arm move through the workspace to reach a certain point? To do this, assume your robot arm is just a simple mobile robot navigating in 3D space. The end effector will traverse the space just like a mobile robot, except now it must also make sure the other joints and links do not collide with anything too. This is extremely difficult to do . . . What if you want your robot end effector to draw straight lines with a pencil? Getting it to go from point A to point B in a straight line is relatively simple to solve. What your robot should do, by using inverse kinematics, is go to many points between point A and point B. The final motion will come out as a smooth straight line. You can not only do this method with straight lines, but curved ones too. On expensive professional robotic arms all you need to do is program two points, and tell the robot how to go between the two points (straight line, fast as possible, etc.). For further reading, you could use the wavefront algorithm to plan this two point trajectory. Velocity (and more Motion Planning) Calculating end effector velocity is mathematically complex, so I will go only into the basics. The simplest way to do it is assume your robot arm (held straight out) is a rotating wheel of L diameter. The joint rotates at Y rpm, so therefore the velocity is
Velocity of end effector on straight arm = 2 * pi * radius * rpm
However the end effector does not just rotate about the base, but can go in many directions. The end effector can follow a straight line, or curve, etc. With robot arms, the quickest way between two points is often not a straight line. If two joints have two different motors, or carry different loads, then max velocity can vary between them. When you tell the end effector to go from one point to the next, you have two decisions. Have it follow a straight line between both points, or tell all the joints to go as fast as possible - leaving the end effector to possibly swing wildly between those points. In the image below the end effector of the robot arm is moving from the blue point to the red point. In the top example, the end effector travels a straight line. This is the only possible motion this arm can perform to travel a straight line. In the bottom example, the arm is told to get to the red point as fast as possible. Given many different trajectories, the arm goes the method that allows the joints to rotate the fastest. Which method is better? There are many deciding factors. Usually you want straight lines when the object the arm moves is really heavy, as it requires the momentum change for movement (momentum = mass * velocity). But for maximum speed (perhaps the arm isn't carrying anything, or just light objects) you would want maximum joint speeds. Now suppose you want your robot arm to operate at a certain rotational velocity, how much torque would a joint need? First, lets go back to our FBD: Now lets suppose you want joint J0 to rotate 180 degrees in under 2 seconds, what torque does the J0 motor need? Well, J0 is not affected by gravity, so all we need to consider is momentum and inertia. Putting this in equation form we get this: torque = moment_of_inertia * angular_acceleration breaking that equation into sub components we get: torque = (mass * distance^2) * (change_in_angular_velocity / change_in_time) and change_in_angular_velocity = (angular_velocity1)-(angular_velocity0) angular_velocity = change_in_angle / change_in_time Now assuming at start time 0 that angular_velocity0 is zero, we get torque = (mass * distance^2) * (angular_velocity / change_in_time) where distance is defined as the distance from the rotation axis to the center of mass of the arm: center of mass of the arm = distance = 1/2 * (arm_length) (use arm mass) but you also need to account for the object your arm holds: center of mass of the object = distance = arm_length (use object mass) So then calculate torque for both the arm and then again for the object, then add the two torques together for the total: torque(of_object) + torque(of_arm) = torque(for_motor)And of course, if J0 was additionally affected by gravity, add the torque required to lift the arm to the torque required to reach the velocity you need. To avoid doing this by hand, just use the robot arm calculator. But it gets harder . . . the above equation is for rotational motion and not for straight line motions. Look up something called a Jacobian if you enjoy mathematical pain =P

Arm Sagging Arm sagging is a common affliction of badly designed robot arms. This is when an arm is too long and heavy, bending when outwardly stretched. When designing your arm, make sure the arm is reinforced and lightweight. Do a finite element analysis to determine bending deflection/stress such as I did on my ERP robot:

Keep the heaviest components, such as motors, as close to the robot arm base as possible. It might be a good idea for the middle arm joint to be chain/belt driven by a motor located at the base (to keep the heavy motor on the base and off the arm). The sagging problem is even worse when the arm wobbles between stop-start motions. The solve this, implement a PID controller so as to slow the arm down before it makes a full stop. Sensing Most robot arms only have internal sensors, such as encoders. But for good reasons you may want to add additional sensors, such as video, touch, haptic, etc. A robot arm without video sensing is like an artist painting with his eyes closed. Using basic visual feedback algorithms, a robot arm could go from point to point on its own without a list of preprogrammed positions. Giving the arm a red ball, it could actually reach for it (visual tracking and servoing). If the arm can locate a position in X-Y space of an image, it could then direct the end effector to go to that same X-Y location (by using inverse kinematics). If you are interested in learning more about the vision aspect of visual servoing, please read the Computer Vision Tutorials for more information. Haptic sensing is a little different in that there is a human in the loop. The human controls the robot arm movements remotely. This could be done by wearing a special glove, or by operating a miniature model with position sensors. Robotic arms for amputees are doing a form of haptic sensing. Also to note, some robot arms have feed back sensors (such as touch) that gets directed back to the human (vibrating the glove, locking model joints, etc.).

Tactile sensing (sensing by touch) usually involves force feedback sensors andcurrent sensors. These sensors detect collisions by detecting unexpected force/current spikes, meaning a collision has occurred. A robot end effector can detect a successful grasp, and not grasp too tight or too lightly, just by measuring force. Another method would be to use current limiters - sudden large current draws generally mean a collision/contact has occurred. An arm could also adjust end effector velocity by knowing if it is carrying a heavy object or a light object - perhaps even identify the object by its weight.

http://www.societyofrobots.com/robot_arm_tutorial.shtml