Overview of Parallel Robots | |
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Most industrial robots equipped with serial technology, where each axis is in line relative to the preceding one. The parallel robot on the other hand has three or more prismatic or rotary axes which function parallel to one another. Examples of parallel robots are Tricept, Hexapod and Delta Robots. Both Tricept and hexapod robots use linear motors to control the position of the tool. |
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Tricept Robot: The tricept uses three legs in conjunction with a central pillar to hold the head rigidly in position and then has a standard wrist mounted on it to achieve the orientation. |
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Hexapod Robot: A hexapod has 6-DOF parallel mechanism with six identical kinematics chains to achieve both position and orientation. It composes of a universal joint, a prismatic actuator, and a spherical joint. |
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Delta Robot: The Delta robot has three actuators which control all three translational degrees of freedom of the mobile platform. An additional linkage provides a rotational movement for the end-effector. |
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| The result of the parallel design is a robot that has increased stability and arm rigidity, with faster cycle times than serial technology. As such there is less flexing of the arms which results in high repeatability. In addition, With serial linked robots, the end-of-arm flexing errors are cumulative, whilst in a parallel link structure they are averaged. However, one disadvantage of parallel robots is they tend to have a relatively large footprint-to-workspace ratio, for example, the hexapod parallel robot, easily take up a sizable work area. The exception is the Tricept robot which requires less space. Another limitation of the parallel configuration is that it has a small range of motion due to the configuration of the axes when Compared to a serial link machine. | |
Application Areas of Parallel Robots | |
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Parallel robots are used to assemble automobiles, food products, surgical and many other applications. For instance, the Delta robot is mostly used as a pick-and-place robot. And, almost all flight simulators are based on the hexapod design. They are also used for machining operations where machine tool level tolerances are not required but greater flexibility is. |
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