Investigation of complex surfaces of propellers of vehicles by a mechatronic profilograph

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 and the pro fi lograph is turned on. By means of the control unit, the upper motor moves the laser position sensor along the guide using a screw to the periphery of the measured area, and the lower motor turns the guide to the zero position by rolling the satellite along the fi xed supporting wheel. Then, the program starts only the lower motor and the surface is scanned along the periphery of the area. Using a Bluetooth con- nection, information is transmitted from the sensor with the Bluetooth radio module to the control unit and then to the laptop, both having built-in Bluetooth modules. When the information received the computer program draws a pro fi le along a circle in polar coordinates according to two parameters: the distance be- tween the position sensor and the complex surface of the part, as well as the angle of rotation corresponding to this position from the zero mark according to the angle sensor. The information measurement system of a mechatronic pro fi lograph is a set of functionally integrated technical means such as measuring (sensors), controlling (monitoring and comparison with various pro fi les models), diagnostic (accelerometer, gyro- scope), computing (laptop), control (laptop, electric motors), recording (laptop), displaying (laptop), tele- communications (laptop) and other auxiliary means. This information measurement system is designed to obtain, convert, process and transmit measuring information. It makes a decision on whether the recognized pro fi le belongs to a particular model (smooth, rough, waviness, shaped surface) according to the features that characterize the properties of pro fi les of complex surfaces (slope, curvature, undulation, roughness). Moreover, for each model, the corresponding trajectory of the sensor movement is used, for example, the Archimedes spiral with a given pitch. Consider the trajectory of the laser sensor, which is a curve in the form of an Archimedes spiral (Figure 2), the coordinates of which are determined in polar coordinates by the point of the laser sensor M ( i r , i  , i z ): , 0, i i i i r k z H  ì =ïïíï = = ïî (1) where i r – the displacement of М at the angle i  from the center of rotation, m; i  – the angle of turning of М in i position, rad, i z – the applicate value of М in i position, m; i H – the value of the distance to the surface, m, k – the displacement of М at an angle equal to one rad, determined by the formula: , 2 S k  = (2) where S – the radial pitch of the spiral. The radial pitch of the spiral S rad is calculated by the formula [1]: 2 5 ðàä 1 4 1 , p Z Z S S Z Z æ ö÷ ç= + ÷ ç ÷ ç ÷ çè ø (3) where S p – the pitch of the lead screw; Z 1 – the number of teeth of the satellite 1; Z 2 – the number of teeth of the supporting wheel 2; Z 4 – the number of teeth of the supporting wheel 4; Z 5 – the number of teeth of the satellite 5. The fi nal equation of the Archimedes spiral (1), taking into account equations (2) and (3), will take the form: 2 5 1 4 1 , 2 0, p i i i i Z Z S Z Z r z H   ì æ ö ï ÷ ï ç + ÷ ï ç ÷ ç ï ÷ è ø ï =íïïïï = = ïî . (4) The coordinates , i i x y are related to the angle i  in polar coordinates by the formulas: cos , sin . i i i i i i x r y r   ì =ïïíï = ïî (5)