An idea for a significant enhancement of position accuracy is the direct measurement of the TCP by using a laser tracker system. A laser tracker system is a highly accurate 3D measurement system that uses two angles and one distance to determine the position of a movable retroreflector in space. All systems that are available on the market are designed as stand-alone-systems. The weight, the dimensions and the measuring rate limit the integration in dynamic mechatronic systems.
To solve this problem an innovative laser tracker system on the basis of a galvanometer scanner is presented. The modular construction and the compact dimensions allow an optimal adjustment to the needs of the customer. With a light weight below 6 kg and an efficient FGPA based signal processing unit that guarantees measuring rates of up to 37 kHz the system has essential advantages in contrast to other laser trackers.
The calculation of the 3D coordinates, the interfaces of the sensors and actuators as well as the processing of the interferometer data are completely done in the FPGA.
The velocity of the reflector can be up to several meters per second in lateral direction and 0.7 m/s (split frequency of the laser head) in radial direction. A special calibration algorithm that uses only distances between points was developed to identify the system parameters. The measurement of a segment in a distance of about 1 m showed a 2σ repeatability of better than 9 µm.
Further features like an automatic search algorithm in case of a beam loss, an absolute distance measuring technique for online adaptation of the controller parameters and the possibility to configure the system via the RS232 interface make sure that the system can be easily handled by the operator.
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Press
Compact design and modular setup of system components
