Robotic automation (ROBOTIC TOTAL STATION) or robotic theodolite or theodolite positioning system (TPS)] was used for the first time to measure the deflections of a short-range bridge in response to passing trains. ROBOTIC TOTAL STATION measurements were directed at a reflector placed on one center rail of the historic Greek Gorgopotamos bridge and detected measurement noise (apparent displacements) of up to 61.3 mm when no train occurred and deflections with peaks of 2.5–6 mm for small or larger at train intervals. These results confirm previous experiments and that under certain conditions (mainly favorable weather conditions) ROBOTIC TOTAL STATION can be used to monitor the transitions of relatively rigid bridges and as a useful tool for monitoring the health of structures.
RTS used In Measurement
Measuring the deflections of bridges caused by dynamic and semi-static loads is essential for their design, operation, and structural health (Brownjohn et al. 2010; Bardakis and Fardis 2011), but until recently this was a rather unresolved problem. Systematic measurement of bridge deviations became possible with the invention of the Global Positioning System (GPS) (Robotic Total Station et al. 2004; Meng et al. 2007), provided that there is a clear picture of the horizon and satellites, which is not the case on different railway bridges where passing trains distort or even interfere with Wieser and Brunner 2002). A new alternative geodetic technique is the robotic total station or robotic theodolite (ROBOTIC TOTAL STATION) (or even a geolocation system or theodolite [TPS]), which has been successfully used to measure semi-static deflections (Koo et al. 2012) and the dynamics of relatively long-lived bridges characterized by large deflections (at least several centimeters; Cosser et al. 2003; Lekidis et al. 2005; Wieser and Brunner 2002; Erdogan and Guelal 2009). On the contrary, measuring the response of short-term bridges to dynamic loads, in particular, is a very difficult task because their ROBOTIC TOTAL STATION measurements are usually covered by noise. However, systematic experiments have shown that some ROBOTIC TOTAL STATIONS with improved integrated software can be used to measure amplitudes of a few millimeters and period 1s oscillations (Psimoulis and Stiros 2007, 2008, 2011).
The servomotors move the station telescope horizontally and vertically to detect the prism. When the system is detected, it “zooms in”, aims, and locks the reflector with high accuracy. Robotic overall position: I know what it is, I know what it does, but how does it work?
Several of the instruments listed in the survey, produced by state-of-the-art total stations, are capable of automatically identifying, identifying, aligning, and locking the prism. These robotic units (ROBOTIC TOTAL STATION) were first used by a Geodimeter in 1990 and are equipped with servomotors that automatically rotate the instrument horizontally and vertically, and an advanced tracking sensor (ATS) according to the prism. The communication link between the ROBOTIC TOTAL STATION and the prism pole allows one operator to be measured while controlling the device from the prism pole. ROBOTIC TOTAL STATION also allows monitoring of uncontrolled stress. Usually, the communication connection is established with radio signals, but some systems also use infrared signals.
The introduction of ROBOTIC TOTAL STATION has made it possible to increase the productivity of surveyors. for example, in performing measurements to create digital elevation models, built verification and hydrographic studies. However, automatic control of bulldozers, graders, excavators, combine harvesters, tractors and scrapers, in short, machine control, has become a significant new application. ROBOTIC TOTAL STATION is also often used for uncontrolled stress control in structures such as dams and factory chimneys. The most useful feature for measurement applications is that only one meter can do the job, saving time and money. Accuracy is high even in low visibility (night).
History of RTS
A total station may be called robotic if it is able automatically to follow a prism moving through 3D space; the key to this feature is the communication link between base-station and prism pole. In the almost twenty years of ROBOTIC TOTA STATION a diversity of communication solutions have been developed. The first stations were aimed by measuring the strength of the laser beam reflected at the prism and locking onto its maximum. They were able to find prisms only when these were mounted on approximately known positions, and they were actually suited only for deformation survey. With time came more advanced solutions. New developments focused particularly on avoiding loss of contact while the prism was moving and automatically tracing it when loss of contact had occurred. Today ROBOTIC TOTAL STATIONS use CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor) imaging sensors to track the prism. These sensors increase the field of view so that there is no longer any need to know the approximate location of the prism. By computing the shift indicated by the imaging sensor they even allow accurate measurement when the prism is not in line with the optical axis of the theodolite.
To avoid loss of contact caused, for example, by interruption of the signal by a vehicle driving between base-station and prism, the software is used that predicts the prism’s path. This may often, but not always prevent loss of contact. To re-establish contact after loss, solutions have been developed based on making a quick laser scan of the broad environment, a technology Leica has termed Power Search. Another method makes use of active prisms. Unlike their passive counterpart Robotic Total Station, active prisms themselves generate signals that are received by the base station and direct targeting of the prism. Use of active sensors also avoids faulty aiming at reflective objects, such as traffic signs, windows or vehicle mirrors. The ability to generate signals on the prism side comes at a price: increased complexity, cost, and weight.
More on the Robotic Total Station and solutions are out there: https://www.satlab.com.se/product_uri/slt-series-total-station/
