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The aim of this study was to investigate and analyze the separation process of poly (ethylene terephthalate) and high-density polyethylene mixture. The research studied the influence of parameters of tribocharging and separation processes on the quality of separation. The research was carried out using a developed test stand consisting of a test tribocharger and a dedicated drum-type electrostatic separator. Both the separator and the tribocharger have been designed as automated test benches to assess the quality of plastic separation. In order to assess the quality of electrostatic separation of plastics, an original method based on the use of a dedicated vision system was used. The research was conducted in two stages. Firstly, the influence of the tribocharging process parameters on the efficiency of the process, i.e., the charge collected, was investigated. The next stage of the research was focused on the analysis of the influence of the separation process parameters on its effectiveness. The obtained results were presented and discussed. On the basis of the conducted research, the parameters of the tribocharging and separation processes affecting their effectiveness were determined.

This paper presents the contemporary problems of polymer waste recycling, mainly recycling cables from end-of-life vehicles. The authors developed a new material based on mixed polymer waste (ASR) modified with a ductile polymer, mainly recycled low-density polyethylene (rLDPE), to produce moisture-resistant boards with beneficial mechanical properties. The ASR-based compositions without and with homogenization process—including physical, chemical, and shear-assisted compatibilization—were successfully applied and verified by evaluating final recycled product properties. The results showed that recycled polyethylene (rLDPE) was effective as a modifier increasing tensile modulus and flexural strength compare to an ASR mixture. It was found that the adding 5 wt % of polyethylene-grafted maleic anhydride (PE-g-MAH) as a compatibilizer to the ASR mixture significantly increases the homogenization of the components in the ASR matrix. The optimal solution for management cable waste is the manufacture of ASR composites with homogenization using an internal mixer the adding 20 wt % of rLDPE and 5 wt % of PE-g-MAH to the mixed plastics cable waste. The results obtained demonstrate that the hot-pressing with the pre-blending with rLDPE and compatibilizer of the ASR based waste provides a high gain in mechanical and usage properties, enabling the circular economy of plastics from automotive cables.

This paper describes the preliminary design and characterization of a dual piezo-bimorph driven micro flapping wing mechanism for potential application in micro aerial vehicle designs. The basic form of the mechanism is inspired by a dragonfly insect. The wing motion is actuated by two piezoelectric bender actuators. The skeletal structure of the wing is manufactured using 3D printing technology, where Kapton film is laminated to the printed ABS skeletal frame. Finite element analysis (FEA) is used to guide the design of the mechanical dynamics of the wing mechanism, where predicted resonances between 10 to approximately 250 Hz are shown. Experimental results are shown to demonstrate basic functionality and operation of the wing, particularly at and near the first resonance. The results also show good agreement with the FEA model.

Plastics recycling has become a key industry in developed countries, to reduce ecological damage and save non-renewable resources. This paper discusses the concept and the design of electrostatic separator as a test bench for the separation of different plastics in recycling applications. In the automotive recycling process, all these waste materials must be processed further for re-entering the cycle or thermal utilization. The following application presents the possibility of research and technological tests by changing several parameters, such as a position of the electrodes, control of the polarity and voltage, variable speed of feeder and drum, and also tribo-electrification parameters (time, intensity). The impact of process parameters on the efficiency of the plastic separation can be analyzed by the developed a specialized computer vision system. The preliminary results of conducted tests showed that separation is dependent on many variations of parameters. The results of this study indicate that the proposed innovative design of the research stand ensures the high research potential of the proposed equipment.

The aim of this study was to investigate and analyze the impact of selected parameters during the tribocharging process of shredded poly(ethylene terephthalate) (PET) and high-density polyethylene (PE-HD) plastics on accumulated electric charge and electrostatic separation effectiveness. The accumulation of electric charge on surfaces of polymer particles as a result of their circular motion forced by the airflow cyclone container was investigated. The impact of the container material, time of tribocharging and the airflow intensity were experimentally examined. A container in which the particles of the considered polymers are electrified with opposite charges was selected. A high ability to accumulate surface charge on small particles of both polymers was demonstrated. The electrified mixed PET/PE-HD was subjected to a separation process. An electrostatic separator designed and constructed by the authors was used for to the separation. In turn, to assess the effectiveness of this separation, a dedicated vision system was used. Based on the result of the carried out tests, it has been assumed that the proposed approach’s effectiveness has been demonstrated by means of empirical validation.

Piezoelectric bending actuators, also known as bimorphs, are characterized by very good dynamic properties and by displacements in a range of a few millimeters. Therefore these actuators are used in a wide range of applications. However their usage is limited because they require supplying amplifiers with output voltage of about 200 V, which are rather expensive. This paper presents investigation results of such amplifiers with high voltage output. The model of a piezobending actuator is proposed and implemented in Matlab-Simulink software in order to simulate the behavior of the actuator supplied by the amplifiers. The simulation results are presented and compared with investigation results of high voltage amplifier used for supplying a piezoactuator. The influence of current limitation of operational amplifier on the actuator current is tested. Finally, a low cost audio power amplifier is proposed to control the piezobender actuator (as a cheaper alternative to the high-voltage amplifier) and its investigations results are presented in the paper.

Electrohydraulic servo drives can be found in many industrial applications. A typical design of a servovalve uses the known torque motor. The main concept of designing the modification of the servovalve described in the paper was concern about the application of a piezobender as an actuator, working between nozzles as a flapper, at a control stage. The paper presents and investigates the design of a power amplifier for piezobenders and a digital controller for an electrohydraulic servo valve with a piezobender element. The article shows and discusses the main concept of design and the results of experimental investigation.

The paper is focused on study of new type of vibration control damper which has been designed, machined, assembled, and calibrated by authors. In typical oil dampers, attenuation force is generated by fixed orifices, where oil passes from one chamber to another. More advanced designs include variable orifices, where it is possible to regulate precisely flow area, e.g., by proportional valve. Thus, these solutions are so-called valve mode, also very popular in whole group of magnetorheological dampers. Another known in engineering type of dampers is based on viscous friction. Steel rood passed through cylinder head, where interference fit creates movement resistance. This paper proposes novel design of damper, where in order to control damping force, simple direct current motor and special mechanism, similar to wedge, has been proposed. To perform basic research on damper’s characteristics, special test stand was designed. Crankshaft mechanism was used to generate reciprocating movement. During tests, one end fixed damper was connected to slider by force transducer. To describe phenomenon of variable damping force, force–displacement and force–velocity characteristics have been registered and described.

The paper describes theoretical and experimental investigation of applying Bouc-Wen model in displacement modeling of piezelectric ring benders. Under the increasing demand for more accurate position control systems, various hysteresis models appropriate for control purpose of mechanical systems have been proposed. Most of these models are based on phenomenological approach, for example: Prandtl–Ishlinskii or Krasnosel’skii-Pokrovskii and other, friction based like Maxwell-slip model. This paper presents a model described in analytical form, called the Bouc-Wen model, appropriate for position control purpose. Paper presents histeresis investigation results of Noliac CMBR05 ring bender under different voltages. Furthermore, article depicts how model was numerically implemented and investigated on dSpace Control System with Matlab Simulink Software for future research on real time position control with inverted hysteresis model.

This paper describes a new robotized station for soldering of through-hole elements on printed circuits boards (PCB). The general structure of this station with the SCARA type robot is presented along with the computer-based control system. The software prepared for control and for the programming procedures is described. The developed computer system software, whose structure is also presented, is applied for robot programming. The first main aim is to develop the data retrieval from the Gerber file and to use them to direct soldering robot programming. The second aim of the research presented in this paper is the application of the visual system for pads coordinate recognition. The system is presented and verified.

Electrohydraulic servo drives can be found in many industrial applications. A typical design of a servo valve uses the known torque motor. The main concept of the design modification in the presented servovalve was concerned in the application of a piezoelectric bender actuator in the first valve stage, working between nozzles as a flapper. Reason for that is very complex machining and assembling processes of torque motor, where tight tolerances significantly increase cost of such transducer. The biggest advantage of piezo bender is simplification of this stage, moreover piezo bender provides better dynamic properties. Piezo bender belongs to group of so-called smart materials. In this case it can bend under external stimulus in the form of electric field. Displacement of free end of piezo bender vs. applied voltage is distinguished by hysteresis which hinder control process, but it can be effectively compensated by proper mathematical model. Authors present in the paper piezo control stage concept and experimental results. Authors prepared for tested sevovalve Matlab Simulink model which is described in this paper. Results of model simulation and servovalve experimental researches were compared and discussed.

The article presents a new approach for noise reduction of a household washing machine. The noise sources and phenomenon were described. After investigation of a currently used solution, and alternative available solutions, a new approach was presented. Design and tests of a low costs magnetorheological fluid, semi-active damper were presented. The input parameters for the new damper were identified on the base of investigation of a viscous damper, used in washing machines. The described MR damper was applied in a washing machine suspension system. Next, a study of washing machine acceleration RMS for different unbalanced masses and durum rotations, were performed. During this research the new damper was switched on and off, to shows it influence on the acceleration. The end results show that the new designed dampers can strongly reduce the vibrations of the washing machine housing and its plastic components.

This paper describes investigations of a low cost high voltage amplifier, which was based on specialized operational amplifiers. The purpose of the amplifier is to control piezoelectric actuators with many electrodes, such as bimorph benders, piezoelectric tubes, ring and disc benders. Proposed amplifier has two independent channels which can be configured for the specific research aim. Every channel of the device can works in inverted or non inverted mode. Also the voltage gain and current limit can be set separately.

The article present basic research of the piezoelectric tube actuator. In this study the actuator was tested for various DC voltages. Further hysteresis and creep effect of the piezo ceramic material were presented. The next point of this research was positioning control of tube under closed loop control. For this purpose classic PID control algorithm was applied, with a negative feedback from laser displacement sensor. The control software was developed under Matlab Simulink and dSPACE control system, which allows fast modification and testing.