8 ROBOTIC COMPUTER SYSTEMS AND PROGRAMMING DESIGN AND

8. ROBOTIC COMPUTER SYSTEMS AND PROGRAMMING DESIGN AND APPLICATIONS OF INDUSTRIAL ROBOTS SABARIGIRIVASAN. R I S B N 978 -81 -908268 -0 -8

Computer System of a Robot 1. A robot is programmable hence it should have adequate computing facilities. 2. Main components of a computing system are broadly classified into two types, they are a) Hardware b) Software 2

Hardware 1. All electronic devices forming the physical components of the computing system are known as Hardware. 2. Hardware components a) b) c) d) e) Microprocessor for data processing and controlling Temporary memory unit Permanent storage unit Display unit Communication peripherals 3

Hierarchy of Robot Computer 1. Processors in the robot computer system is arranged in a hierarchical manner. 2. The robot computer is configured with a) Master controller b) Slave controller 3. Master controller communicates with all slave controller for sending and receiving control and data signals. 4

Hierarchy of Robot Computer 5

Master Controller 1. Master controller has its architecture and operating principles similar to a personal computer. 2. It has three main units a) Input unit • Key board, Teach pendant b) Central Processing Unit (CPU) • 32 bit microprocessor • RAM, Permanent storage memory c) Display unit • CRT or LCD Monitor 6

Master Controller 7

Microprocessor 8

Slave Controller 1. The individual joint controller provided for each joint is referred as slave controller. 2. 8 bit or 16 bit microcontrollers are used. 3. A microcontroller is a microprocessor with low computing power but with additional circuits like integrated ADC, CCP module, PWM module, USART module. 4. It has two types of onboard memory. a) RAM – Used to store temporary data. b) ROM – Used to store program instructions. • OTPROM and Flash memory are widely used. 9

Microcontroller 10

Communication Systems 1. Communication between two units is needed for exchanging data and control signals. 2. Communication types a) Serial communication b) Parallel communication 3. Data transmission modes a) Simplex mode b) Duplex mode • Half duplex mode • Full duplex mode 11

Serial Communication 12

Parallel Communication 13

Data Transmission Modes 14

Communication Interface and Protocols 1. RS 232 – 20 Kbps over 15 m 2. Universal Synchronous Asynchronous Receiver Transmitter (USART) 3. Universal Serial Bus (USB) a) USB 1. 0 – 1. 5 Mbps b) USB 1. 1 – 12 Mbps c) USB 2. 0 – 480 Mbps 4. Controller Area Network (CAN) – 1 Mbps over 40 m 15

USART 16

CAN 17

Additional Peripherals 1. Additional I/O channels are provided for interfacing additional sensors and controllers 2. Analog to Digital Converter (ADC) Used to convert an analog signal to digital format. 3. Digital to Analog Converter (DAC) Used to convert digital codes into its proportional analog signal. 18

Analog to Digital Converter 19

Digital to Analog Converter 20

Software 1. Software is the set of instructions fed in a specific format to the hardware to perform certain task in the required sequence. 2. Software is broadly classified into two types they are a) Operating system b) Application programs 21

Operating System 1. Operating system is the computer program that supervises and coordinates the functions of various hardware components inter connected in the computer system. 2. It accepts the robot program written in high level language and converts it into machine language. 3. Compiler or Interpreter is used for this purpose. 22

Operating System 4. Machine language is the assembly language program that has opcodes in binary form. 5. Each opcode has a specific function to do for a specific kind of microprocessor. 6. The operating system provides three main operating modes for organizing a program, a) Monitor mode b) Run mode c) Edit mode 23

Application Programs 1. They are the actual robot program fed to the computer for controlling the robot motion. 2. They are created individually for each kind of application. 3. They are actually compiled by human programmers using any one of the programming methods. 24

Robot Programming 1. Programming is the process of loading a set of instructions in a specific format so that the robot controller can process them to move the arm and the endeffector. 2. The set of instructions that drives the robot is known as robot program. 3. Robot programming is of two types a) Lead through programming b) Textual programming 25

Lead through Programming 1. In lead through programming the robot is moved along the required path to the required destination and the joint angles and positions generated during this motion are recorded in the controllers memory. 2. These set of points recorded during the motion constitute the program for the path generated. 26

Lead through Programming 1. It is of two types, a) Manual lead through programming • Robot is moved manually by the operator using a special handle. b) Powered lead through programming • Robot is moved by powering its own actuators. • Teach pendant is used to move the robot while programming. • Joint motions, motion along xyz coordinates and tool point coordinate motions are employed to define points on the required path. 27

Textual Programming 1. Instructions that are required to drive the robot are compiled using a high level language that has human readable words. 2. The program in the high level language is converted into machine language with the help of a compiler or interpreter. 3. The controller can thus process the machine code to drive the robot. 28

Programming Languages 1. Generations of language a) First generation language – Limited capabilities b) Second generation language – Advanced features c) Future generation languages – World modeling 2. Some programming languages a) b) c) d) e) AL AML RAIL RPL VAL 29

Artificial Intelligence 1. Artificial intelligence (AI) is the intelligence capability built into a machine to function and make decision of their own in response to their environmental stimulants. 2. AI enabled machine can behave just like humans or other natural animals do. 3. AI for a machine can be achieved by processing vast amounts of data in a sequential manner. 30

Artificial Intelligence 4. It needs a computer with very large storage and computing power. 5. Features of an AI enabled machine a) Problem solving b) Learning c) Video and audio based recognition 31

Methods to achieve Artificial Intelligence 1. Decision making using AI is achieved by analyzing vast amount of data representing the characteristic properties of a problem or situation. 2. Techniques to achieve AI a) Logical interpretation – Boolean algebra b) Artificial Neural Networks c) Frames 32

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