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Sensorless compensation system for thermal deformations of ball screws in machine tools drives

Abstract

The article presents constructional, technological and operational issues associated with the compensation of thermal deformations of ball screw drives. Further, it demonstrates the analysis of a new sensorless compensation method relying on coordinated computation of data fed directly from the drive and the control system in combination with the information pertaining to the operational history of the servo drive, retrieved with the use of an artificial neural networks (ANN)-based learning system. Preliminary ANN-based models, developed to simulate energy dissipation resulting from the friction in the screw-cap assembly and convection of heat are expounded upon, as are the processes of data selection and ANN learning. In conclusion, the article presents the results of simulation studies and preliminary experimental evidence confirming the applicability of the proposed method, efficiently compensating for the thermal elongation of the ball screw in machine tool drives.

Open access
Shape optimization of the modular press body

Abstract

A paper contains an optimization algorithm of cross-sectional dimensions of a modular press body for the minimum mass criterion. Parameters of the wall thickness and the angle of their inclination relative to the base of section are assumed as the decision variables. The overall dimensions are treated as a constant. The optimal values of parameters were calculated using numerical method of the tool Solver in the program Microsoft Excel. The results of the optimization procedure helped reduce body weight by 27% while maintaining the required rigidity of the body.

Open access
Stabilisation problem in biaxial platform

Abstract

The article describes investigation of rolling ball stabilization problem on a biaxial platform. The aim of the control system proposed here is to stabilize ball moving on a plane in equilibrium point. The authors proposed a control algorithm based on cascade PID and they compared it with another control method. The article shows the results of the accuracy of ball stabilization and influence of applied filter on the signal waveform. The application used to detect the ball position measured by digital camera has been written using a cross platform .Net wrapper to the OpenCV image processing library - EmguCV. The authors used the bipolar stepper motor with dedicated electronic controller. The data between the computer and the designed controller are sent with use of the RS232 standard. The control stand is based on ATmega series microcontroller.

Open access
The use of IR thermography to show the mold and part temperature evolution in injection molding

Abstract

This study concerns the application of infrared camera for injection molding analysis by measuring temperatures of both injection molded parts and injection mold cavities in a function of injection cycles. The mold with two cavities, differing in thickness (1 and 3 mm), and a cold direct runner was used. Isotactic polypropylene homopolymer was utilized to produce parts. Mold temperature was set at 22°C and controlled by a water chiller. Five measuring points were determined: SP1, SP2 (placed in the 3 mm cavity), SP3, SP4 (located in the 1 mm cavity) and SP5 around an injection molding gate. Our investigations showed that the highest temperature is localized around SP2 point and the lowest at SP4. Also, it was proved that even after 62 injection molding cycles, temperatures of cavities were not stable, revealing their further increase with each cycle.

Open access
Collision Risk Mitigating System for Light Rail Vehicles(LRV)

Abstract

This piece is dedicated tothedescription of the development of collision risk mitigating system. The proposed concept of control system is designed to enhance safety ofpassengers, a driver and other people in vicinityof light rail vehicles (tramways).The requirements were fulfilled thanks to the application of lidar sensor and feature of vehicle positioning on the track map created basingon precise measurements with the use of satellite navigation systemReal Time Kinematic. The map allows to eliminate errors of system operation and to enhance resistance to unfavorable ambient conditions, i.e.temperature or fog. The system calculates work braking distance for particular vehicle speed. In case of obstacle detection which is closer to vehicle than the calculated braking distance, the driver is informed about a collision risk with a buzzer and optical signalization. The system has already been implemented and tested.

Open access
The Influence of the Type of Coating on the Cutting Tool Wear During Turning Of 316L Austenitic Stainless Steel

Abstract

The paper presents the influence of coatings applied with the use of PVD method on cutting tools on the wear of the tool and compares it with an uncoated P25 cemented carbide plate. During the experiment, two types of TiAlN coatings were used, applied in various proportions, as well as TiN coating. During the tests, the average width of the wear band on the flank face in B VBBzone and the width of KBcrater were monitored. Moreover, the scanning analysis of the tool was conducted in order to determine the intensity of adhesive wear. The lowest values of selected tool wear indicators were found out with the use of TiAlN coating applied in eight layers in the proportions 33/67% -TiN/TiAlN. The scanning analysis proved the highest adhesive wear of the uncoated P25 cemented carbide plate, as well as increased abrasive wear of the flank face and the formation of a crater in comparison with coated plates.

Open access