User talk:Ajayramsudhir

pc based 5 axis robot control
BLOCK DIAGRAM:

FIGURE 1: BLOCK DIAGRAM OF PC BASED 5 AXIS ROBOT CONTROLLER

WORKING: The robotic frame is controlled by commands through personal computer. The visual basic front end design is done in the personal computer. The commands from the PC (present in the control room) are transmitted through the RF transreceiver. Hence the commands are transmitted to the RF transreceiver which is kept at the robot working area. The commands received by the RF transreceiver are given to the microcontroller (PIC18F452). The microcontroller produces the control signals according to the commands received. The control signals are given to mini SSC II servo controller board which is connected by USART port. The servo controller controls the servo motors which are present in the robotic arm. The ultrasonic distance sensor which is connected in the robotic arm senses the obstacles and measures the distance between obstacles and robotic frame. The measured distance is also displayed in front end to avoid damages to the robotic frame. The wireless camera is also connected in robot, which captures the images in front of the robot. The captured images are also displayed in the front end. Hence we can visualize the handling object.

ROBOTIC FRAME: The robot consists of 5 mechanical axis. The robot features base rotation, shoulder, elbow and wrist motion, with a functional gripper to make five independent axis of movement. Hence the robot works like a human hand. Each axis is connected by a servo motor except shoulder axis. The shoulder consists of 2 servo motors to sustain the load. FIGURE 2: ROBOTIC FRAME

As the 5 axis works independently the degree of freedom of the robot is high. The working envelope of the robot is shown below, FIGURE 3: WORKING ENVELOPE OF ROBOT FRONT PAGE DESIGN: Here we use visual basic for creating front end design. In this we have scroll bars for control the various servo motors and its corresponding angle of rotation also displayed in the text box. Delay time 5 seconds is required to initialize the servo controller board to work in mini SSC II mode. The distance between the obstacle and the robot will be displayed in the monitor. Video of the handling object is also displayed in front end page. By using MS COMM control 6.0 tools we interface visual basic coding to serial port.

FIGURE 4: FRONT END DESIGN TO CONTROL THE ROBOT

RF TRANSRECEIVER: This is an FSK Transceiver module, which is designed using the IC (CC2500). It is a true single-chip transceiver. It is based on 3 wire digital serial interface and an entire Phase- Locked Loop (PLL) for precise local oscillator generation .so the frequency could be setting. It can use in UART port of microcontroller. It gives 100 meters range with provided external antenna. It provides extensive hardware support for packet handling, data buffering, burst transmissions, clear channel assessment, link quality indication and wake on radio. It can be used in 2400-2483.5 MHz ISM/SRD band systems. It could easily to design product requiring wireless connectivity. It provides data rate of 500 kbps. RF Transreceiver is interfaced with microcontroller through SPI protocol. Features: 	 Low power consumption. 	 High sensitivity (type -104dBm) 	 Programmable output power -20dBm~1dBm 	 Operation temperature range: -40~+85 deg C 	 Operation voltage: 1.8~3.6 Volts. 	 Available frequency at: 2.4~2.483 GHz 	 Digital RSSI

MICROCONTROLLER (PIC18F452): It is a 40 pin IC with operating frequency of 40 MHz. It has 32 Kbytes program memory and 256 bytes Data EEPROM Memory. It has 5 I/O ports named PORT-A, B, C, D, E and 2 Capture/Compare/PWM (CCP) Modules. It has 4 timers. Master Synchronous Serial Port (MSSP) module: It is a serial interface useful for communicating with other peripheral or microcontroller devices. These peripheral devices may be serial EEPROMs, shift registers, display drivers, A/D converters, etc. The MSSP module can operate in one of two modes - 3-wire SPI (supports all 4 SPI modes) - I2C Master and Slave mode

SPI mode: SPI mode is used for connecting RF Transreceiver. The SPI mode allows 8-bits of data to be synchronously transmitted and received, simultaneously. All four modes of SPI are supported. To accomplish communication, typically three pins are used: • Serial Data out (SDO) - RC5/SDO • Serial Data in (SDI) - RC4/SDI/SDA • Serial Clock (SCK) - RC3/SCK/SCL/LVDIN

Addressable USART module: It has Addressable USART module that Supports RS-485 and RS-232 interface. The mini SSC II servo controller board is connected through RS-232. The Universal Synchronous Asynchronous Receiver Transmitter (USART) module is one of the two serial I/O modules. (USART is also known as a Serial Communications Interface or SCI.) The USART can be configured as a full duplex asynchronous system that can communicate with peripheral devices, such as personal computers, or it can be configured as a half-duplex synchronous system that can communicate with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs, etc. The USART can be configured in the following modes: • Asynchronous (full-duplex) • Synchronous - Master (half-duplex) • Synchronous - Slave (half-duplex)

MINI SSC II SERVO CONTROLLER: The “Serial Servo Controller (USART & SPI)” is compact for control up to eight RC servos from a PC or microcontroller. Each servo speed and range can be controlled independently. This servo controller supports USART and SPI communications. Here we use USART communication to interface with microcontroller. We control the servomotors by sending the desired command. Servo Controller supports Mini SSCII protocol. FIGURE 5: MINI SSC II SERVO CONTROLLER ARM GRIPPER: This functional gripper is used to hold the objects. The servo motor connected to the gripper is made to rotate in the range of 0 to 90 degree. By varying the servo controller range in the front end we can control the gripper. The range of the scroll bar value is 1 to 127. FIGURE 6: GRIPPER ACTION ULTRASONIC DISTANCE SENSOR: "ECHO" Ultrasonic Distance Sensor with ASCII serial O/P provides very short to long-range detection and ranging. The sensor provides precise, stable, non-contact distance measurements from about 2 cm to 4 meters with very high accuracy. Its compact size, higher range and easy usability make it a handy sensor for distance measurement and mapping. The Sensor is interfaced with microcontroller RX pin (USART). Every 500 ms, the sensor transmits an ultrasonic burst and sends out ASCII value of distance (through its signal pin at 9600 baud rate) that corresponds to the time required for the burst echo to return to the sensor. The sensor outputs the error message only if the distance is out of range i.e. above 4.3 m.

APPLICATIONS: The robot can be used in 	Handling hazardous waste in the nuclear reactor. It replaces humans working in such hazardous jobs. 	Careful handling of equipments in laboratories. 	 Handling toxic chemicals in industries.

CONCLUSION: This project describes a new economical solution of robot control systems. The robot provides easy control with high efficiency and accuracy. Working of the humans in handling nuclear waste is fatal. Hence our robot replaces humans at hazardous jobs. Since RF data communication is used, the robot can work up to 100meters range. As we used servomotors for controlling arms, Out-of-step condition not possible (will rotate even if a heavier load is applied).