ROBOTICA & MANAGEMENT - Vol. 23, No. 2, December 2018, pp. 3-8

A Functional Model of a Serial Redundant Robot

Ovidiu Antonescu *, Mariana Trofimescu **, Constantin Brezeanu ***

* University "Politehnica" of Bucharest,
e-mail: oval33(at)
** Dinu Lipatti High School, Bucharest
e-mail: banitamariana(at)
*** Silcotub S. A. (Tenaris Group) Calarasi
e-mail: br79c(at)

Abstract: The paper presents the mobility calculation, geometry and kinematics of a robot arm. It is a serial robot whose main spatial kinematic chain consists of four revolute joints. Four continuous current electric motors are used for driving the serial robot. We carried out a structural analysis of the robot, which has four mobilities. We have used matrix calculus for the kinematic analysis of the serial robot arm so that we obtained the three Cartesian coordinates of the characteristic points according to the four independent angular parameters. By means of reversed kinematics, when the three coordinates of the end effector point are imposed, we deduced three non-linear equations with four angular unknown parameters, which proves the robot’s redundancy (an extra unknown parameter). Regarding the prehension mechanism, the kinematic schema with two symmetrical parallelograms has been presented, which ensures the circular translational motion of the two fingers. 

 serial robot, kinematic schema, mobility, matrix calculus, end effector.

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