Project Abstract

The modern manufacturing environment is dynamic and uncertain. In line with the global trend in manufacturing, this project is carried out to explore into the potentials of robots in manufacturing, service industry, and domestic use. The robot was designed and constructed to incorporate the use of mobile phones as control mechanism via dual-tone-multiple frequency (DTMF). Various components such as the Gripper, Gears, Chains, and Control system were designed with good factor of safety; with factors such as vibration, inertia concerns, availability, and reliability taken into consideration. MATLAB software was used extensively in the design, simulation and testing. The Root-locus, Disturbance response, and Polar plots of the control system transfer function were plotted using MATLAB. The results obtained showed good performance characteristics; such as stability of the control system, good damping characteristics, and excellent time response to step and impulse inputs.Keywords Design, construction, GSM-controlled, pick and place, robotNOMENCLATURES= Number of teeth of the driving gear
= Number of teeth of the driven gear= Rotational speed of the driving gear (rpm)
= Rotational speed of the driven gear (rpm)
= Length of chain (cm)
= No of teeth of the driving sprocket (teeth)
= No of teeth of the driven sprocket (teeth)
= Pitch of chain (cm)
= Centre-centre distance of chain (cm)= Internal friction in motor (kg/ms)
! = Armature inductance (mH)
“# = Motor constant (Nm/A)
! = Armature resistance ()
“$ = Back EMF constant (Vs/rad)
%# = Maximum power (W)
” = Gain
& = Transfer function
‘( = Angular frequency of internal vibration of the control system (rad/s)
) = Damping ratio
* = Disturbance signal
+(,) = Steady-state error
“- = Feedback transfer function
‘. = Angular speed generated by the load disturbance (rad/s)

Project Overview

The aftermath of the Second World War was rapid development in science and technology with significant inventions, such as: numerical control, micro-controllers and microprocessors, chip technology, and software development. The late 20th century manufacturing industry witnessed rapid use of computers, information and communication technology. There is no doubt that automation and computerization is the future of manufacturing. Various factors such as increasing labour cost, adverse influences from trade unions, international organizations and government policies, and grave consequences of industrial accidents, musculoskeletal disorders and other work-related diseases have caused a global shift from human-centered manufacturing to the era of robotics, artificial intelligence, and possibly, an unmanned factory.Since 1961, when the first digital and programmable robot -Unimate” invented by George Devol, in 1954, was sold to General Motors where it was used to lift pieces of hot metal from die-casting machines; there has been pervasive use of robots in Automobile and Process industries because of its numerous advantages, such as: efficiency, reliability, labour savings, ease of control, improved safety and productivity. These technologies deal with automatic machines that can take the place of man in dangerous environment or manufacturing processes, or resemble humans in appearance, behavior, and/or cognition.In recent times, Robots have replaced human in the assistance of performing those repetitive and dangerous tasks which humans prefer not to do or are unable to do due to the size limitations, or even those such as in outer space or at the bottom of the sea where human could not survive the extreme environments. Robots are designed to incorporate components such as mechanical elements (gears, springs, arm, gripper, base etc.), servomechanism, actuators, position feedback mechanism etc. Early designs made use of CNC, programmable and reprogrammable controllers, and the use of infra-red remote controllers. The use of GSM controllers were introduced due the obvious advantages, such as: global coverage, reliability, ease of control, and ability to effectuate control operation from any part of world. Talpur and Shaikh [1] designed a micro-controller based pick and place robot for a food manufacturing line; while Khakurel et al. [2] designed a robot for regulating the speed of DC motors using mobile phones. Even though the same methodology was adopted for this work, the complexity, degree of freedom and application defers from previous designs.Unfortunately, the rapid advancement in field of robotics has not been explored in Nigeria. The manufacturing sector has witnessed a stunted growth, and notable decline in productivity because of the adverse effects of its political, economic, social and technological (PEST) environment; while multi-national organizations are decamping; small and medium-scale manufacturing factories are shutting down. Nigeria’s inability to keep abreast with the rapid changing technologies, especially in robotics, has made manufacturing unattractive to investors. No doubt, the growth of the manufacturing industry in Japan is closely related to their technological advancement in the field of robotics and its applications to the various aspects of production. The introduction of robotics in manufacturing is a major step in revamping the Nigeria’s manufacturing industry. Its wide range of applications in industrial, service sector and domestic uses makes it a sine-qua-non for a sustainable all-round development of the nation’s economy.This paper presents the design and construction of a GSM-controlled pick and place robot.The various components were considered and designed for efficient performance.2. DESCRIPTION OF THE ROBOTThe main components of the robot include the arm, elbow, base, gripper, the controller circuit, and two 12V 6Ah batteries. The rotational movement of the gripper, arm, and elbow is achieved using three DC wiper motors attached to each component. An additional DC stepping motor attached at the interior top of the base control the 360º rotation of the elbow, arm and gripper components. Beneath the base have two DC wiper motors that provide motion to the two rear wheels via chain drive mechanism. These control the forward/backward motion and rotary motion of the base. Two castor wheels fitted at the front provides mobility to the base. The controller circuitry and the 12V DC are housed inside the metallic base. The main components of controller circuit are CM 8870 tone decoder, AT 89S52 microcontroller, electromagnetic relays, bridge rectifiers, and resistive and capacitive components. The batteries provide power to the controller circuit and drive the motors. Provision was made for charging the batteries using AC power source.