Design, implementation and control of a robotic arm using PIC 16F877A microcontroller

ABSTRACT: This thesis focuses on design, implementation and control of a five degree of freedom (DoF) robotic arm using servo motors. The control of robotic arm is achieved by a PIC 16F877A microcontroller. The main duty of microcontroller is to generate pulse width modulation (PWM) signals which are applied to servo motors for achieving the desired rotation. Each servo has a different specification. Therefore, a PWM pulse could have a different effect on servos. Most of the time, it is crucial to apply the exact PWM pulses for achieving the desired rotation. The main advantage of controlling the servo motors with PWM signals is that they can be programmed to have an initial position and to rotate with an exact degree with respect to the requirements. In this study, six servo motors are employed to realize the robotic arm. Four servos are utilized to control the body motion including base, shoulder and elbow and two smaller servos are employed for the motion of end effector. In this thesis, a general formula is derived for finding the pulse duration (pulse width) so as to achieve the desired rotation in each servo motor. The main advantage of this formula is that it can be used for any servo motor with different specification. The operation of designed robotic arm has been experimentally verified. Simulation and experimental results are presented and discussed. Keywords: Microcontroller, Servo Motor, PWM, Roboticiv. …………………………………………………………………………………………………………………………………………………………………………………………………………