| Abstract [eng] |
Camera–based speed enforcement systems have high costs, and for this reason, these systems are too expensive to be used in residential areas. This study designed a speed enforcement system for residential areas. The speed enforcement system's prototype consisted of three main components: a piezoelectric sensor, a control box, and traffic lights. The control box was equipped with electronic components: relays, programmable logic controller, and analog to digital converters. This study designed piezoelectric sensor construction, in which a piezoelectric cable was installed, and the sensor was constructed from an aluminum profile. This profile was used as a protective element for piezo cable from direct mechanical wear from vehicle tires and helped to attach the cable in the needed position on the road. Performed several voltage sensitivity tests for the designed piezoelectric sensor and tested two types of piezoelectric cables, different types of spacer elements, which helped to position the cable in the aluminum. Therefore, was performed a temperature test at 60°C. The obtained voltage sensitivity results revealed that the highest sensitivity of the piezoelectric sensor construction was obtained when the PVDF copolymer piezoelectric cable was used and when the spacer components were used from two-wire cables with a thermo tube. The mechanical stiffness tests as three–point flexural and compression tests revealed that construction was flexible and withstood 10 t loads. Moreover, the compression test and calculations revealed that the piezoelectric construction withstood 39 MPa compressing pressure, while the heavy truck created 4,3 MPa, static pressure, which was 9 times lower. The designed piezoelectric sensor construction investigation revealed that the sensor operated appropriately, obtained analog signal voltages were from 1 V to 9 V with the maximum vehicle speed of 70 km/h. These experiments were conducted to confirm that the sensor is reliable. In addition, the control logic of the speed enforcement system was evaluated and was calculated the estimated cost of the project prototype, which today's prices were more than twice lower compared with the fixed speed control camera system. |
