The development of microprocessor measuring system for the inclination angles of an object relative to the horizon plane

Abstract

The need to measure the angles of inclination is essential for many branches of technology and industry. At the current Ukrainian market of devices there are no domestic accelerometer devices for measuring roll and pitch angles (DMRPA),which would meet the following requirements: the mean square error less than one angular minute in the range of angles ± 10 °, the operating temperature range -40 ... + 70 ° С, output information in a digital code with a discreteness of 1 angular second. Such DMRPAs are needed to control the position of radars and antennas, horizontals of platforms and vehicles.The developed microprocessor system for measuring the inclination angles of an object relative to the horizon plane (MSMIA) provides measurements of the roll and pitch angles in accordance with the above requirements. Issuance of output digital data for consumer is carried out on the interface RS-422.The MSMIA's metal rectangular case consists of a bottom base plate having three legs for attachment to the object base surface and a casing. On the base plate two accelerometer sensors (AS) – primary accelerators transducer, with mutually perpendicular measuring axes, are installed. Digital temperature transducers are installed near them. The analogue parts of the device electronic circuit board contain the electronics for the transformation of the pendulum sensitive elements displacement into the voltage, and electronics of the feedback regulators, the current from which goes to the coil of the reverse compensating converter. This current is proportional to the projection of gravity accelerating on the sensitivity axis of the AS, and is converted into a voltage across the precision resistor. The microcontroller located on the board includes two high precision analogue-digital converters, converting signals from these resistors into digital codes, proportional to measured acceleration. The microcontroller software performs algorithmic compensation for the measurement errors of the acceleration and the calculation of the roll and pitch angles. During the experimental tests, it has been confirmed that for various combinations of temperatures with range - 40 ... + 70 ° С and angles of inclination in the range of ± 10 °, the mean square error is not more than one angular minute, which is unique for the devices presented on the modern domestic market.Consequently, this development will allow Ukraine to establish the production of high-precision MSMIAs to meet the needs of domestic new technical manufacturers. Further research can be directed to the study of long-term instability of the MSMIA's parameters, the reduction of the mean-square error due to the installation of additional temperature sensors and the improvement of temperature errors compensation.