The robot is usually mounted to a linear servo track that allows it to move to the various locations on the table. As mentioned previously, this greatly increases the effective work envelop of the robot and allows it to service more instruments and devices without human intervention. As with the robot joint movements, the
servo motor moves the robot quickly and accurately, utilizing an encoder to provide the controller with positional information. The track is usually treated as an auxiliary axis and is generally controlled by the robot controller. As with the robot servo axes, the controller sends the track servo motor signals to accelerate, move, decelerate, and stop. The speed is easily controlled, and, like the robot axes, positions are saved as an integral part of the robot program. The robot track usually extends for the length of the table for the robotic system to provide as much robot work space as possible. Common track lengths are 2 m and 6 m, although many times custom lengths are available from the system integrator. The modern industrial-grade high-speed linear tracks can move the robot as fast as 3 m/sec, which allows the robot to move quickly from one end of the table to the other. A high-speed linear track is shown in Figure 4.
The fast industrial-grade linear track has several advantages over previous track designs. The higher speed allows the long table to be traversed quickly. This is important, as robotic systems have increased in size to accommodate more instruments to provide higher throughput and a wider range of assays that can be performed on the system. With a 6-m table, the high-speed track can be up to ten times faster than tracks that had been previously supplied with robotic systems.
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