Robotic Joint Essay

MODELING OF BLDC MOTOR FOR ROBOTIC LEG JOINT

1JAGATHEESWARI P 2RENISHA J

1Professor, Department of Electrical and Electronics Engineering, Ponjesly College of Engineering Nagercoil-3

2PG student, Department of Electrical and Electronics Engineering,Ponjesly College of Engineering Nagercoil-3

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Abstract-The space robotics deals with different parameters and conditions of the planets. This robot is buildup of different type of components such as joints, links, joint controllers, different types of sensors, wheels etc. Here a four legged robot is planned in which each leg is composed of five joints. The characterization of these joints is necessary in order to study each leg and kinematics of overall configuration. Hence in this present work an attempt is made to make a mathematical model of a robotic joint which is composed of brushless DC motor, planetary

Robotic leg

A leg has five degrees of rotational freedom and each joint is actuated by a BLDC Motor [3]. The integral components of a Robotic Joint are a BLDC Motor (actuator), encoder (sensor), Controller and the associated mechanical accessories such as gears, harmonic drives which are shown in figure 1. Figure 1.Robotic Leg A brushless DC motor with an integral 33:1 planetary gear head, optical encoder, and brake are used in every joint. This actuator is then used in combination with various size harmonic drive gear [11]. Each joint also incorporates a high precision absolute encoder at the output of the actuator. In a robot, the connection of different manipulator joints is known as Robot Links and the integration of two or more link is called as Robot Joints. Hence it is clear that the BLDC motors have many advantages over brushed DC motors [6]. They are below as: Higher speed ranges Better speed versus torque characteristics Long operating life Noiseless operation Higher dynamic