The aim of this article is to get familiarized with the modern field of robotics and to find the technology know -how. Also here we are using the sophisticated emerging technology -embedded system. Here we have designed a robot arm, controlled by a microcontroller. We choose this deign because it is the most common form of robot we can find anywhere in industries like car assembling, bottling plant, packing section etc. The driver circuits for these motors are to be controlled using 8051 microcontroller with a control key panel. The movement is established using stepper motors. pick and place robots are the small robots using for continuous purpose in the industries then let us go through some thing about pick and place robot by this article .
WHAT IS A ROBOT?
Robot is any machine that does work on its own, automatically after it is programmed by humans. HISTORY OF ROBOTS:
The first robot’s name was Electro and his dog’s name was Sparko .They appeared at the New York world’s fair in 1939. While plugged in, Elektro could say 77 words and move backwards and forwards.
In1920’s, Karl Capek from Czechoslovakia introduced the words first robot on stage.
PICK AND PLACE ROBOT
We are going to design & implement a small model of pick and place robot, which pick and place object any where with in 360degrees and 30 cm diameters around it. The reason for choosing project is, the most extensively form of machine is used in most of the industries like car manufacturing, shipyards, assembling machine etc.
MICROCONROLLERS FOR EMBEDDED SYSTEMS
Microprocessors and microcontroller are widely used in embedded system products.
An embedded system is a system which is dedicated for a single purpose remains unchanged through out its entire life time. An embedded product uses a microprocessor (or microcontroller) to do one task and one task only.
A stepper motor is a widely used device that translates electrical pulses into mechanical movement. It is used for precise position control. # Increase or decrease the RPM (speed) of it.
To vary the RPM of motor we have to vary the PRF (Pulse Repetition frequency). Number of applied pulses will vary number of rotations and last to change direction we have to change pulse sequence.
The circuit mainly consists of three modules -control system, user interface module & a high voltage driver. A control system is nothing but the microcontroller. It has got the following modules.
- User Interface Module.
- Pulse Generator Module.
- Timing Control Module.
- Output Module.
When the keys are pressed the current flows directly to the ground due to the low resistive path making no more current available to the port pins pulling it down to low state, so when ever the keys are pressed the corresponding pins are pulled down. So normally every pin are at a high state giving a value of 1 when ever the keys are pressed the pins are to the low state giving the value 0.
This change is constantly monitored to check for any user interaction. The microcontroller constantly monitors port 0 for any change in port value and if it finds any change it generates the appropriate control signals. The stepper motor driver circuit consists of two stages-low power switching stage& high power switching stage. The function of the low power switching stage is to boost up the low power signal output from the micro controller to a high power signal so as to drive the power transistor.
Care should be taken while connecting the circuit to the motor as stepper has got a tendency to produce very high reverse current compared to DC motor.
To protect the circuit for this reverse current we have connected a diode in reverse bias across the coil supply so that whenever reverse current is present this diode will sink it protecting the circuit.