An Investigation on Mass Variation and its Effect on Positioning and Angular Velocity of the Linkages of a 2-Degree of Freedom Robot Using Direct Dynamic Method

Mechanisms and robots are used for transmission of force and torque and also for performing a precise motion and work. Dynamics plays a critical role in control of robots with sensitive structures. Dynamic-based calculations were perceived more essential than static-based calculations by recent emergence of machines and structures with significantly high speeds and accelerations. By current rapid advancements in technology the application of mechanical principles, particularly dynamics seems highly essential. These principles account for the fundamentals of analysis and design for a wide range of applications including analysis and design of mobile structures, fixed structures under impact loads, robot-like machines, automatically-controlled assemblies, rockets, missiles, spaceships, land and airborne vehicles, electronic projectiles for electrical devices, various equipments including turbines, pumps, reciprocating engines, lifts, tool machines, etc. The present study aims at investigating the variations (increase and decrease) in masses of linkages (arms) of a 2-degree of freedom robot (without degree of freedom in end effector) and the effect of individual variation in each linkage on position and angular velocity of other linkage and ultimately on performance of a robot with 2 degrees of freedom. For the purposes of this study we used Matlab Software and applied direct dynamic method (Newton-Euler Equations).