Vibration monitoring provides a good-quality source of information about the health condition of machines, and it is often based on the use of accelerometers. This article focuses on the use of accelerometer sensors in fabricating a low-cost system for monitoring vibrations in agricultural machines, such as rotary tedders. The aim of the study is to provide useful data on equipment health for improving the durability of such machinery. The electronic prototype, based on the low-cost AVR microcontroller ATmega128 with 10-bit ADC performing a 12-bit measurement, is able to acquire data from an accelerometer weighing up to 10 g. Three sensors were exposed to low accelerations with the use of an exciter, and their static characteristics were presented. Standard experimental tests were used to evaluate the constructed machine monitoring system. The self-contained prototype system was calibrated in a laboratory test rig, and sinusoidal and multisinusoidal excitations were used. Measurements in time and frequency domains were carried out. The amplitude characteristic of the preformed system differed by no more than 15% within a frequency range of 10 Hz–10 kHz, compared to the AVM4000 commercial product. Finally, the system was experimentally tested to measure acceleration at three characteristic points in a rotational tedder, i.e., the solid grease gearbox, the drive shaft bearing and the main frame. The RMS amplitude values of the shaft vibrations on the bearing in relation to the change in the drive shaft speed of two tedders of the same type were evaluated and compared. Additionally, the parameters of kurtosis and crest factor were compared to ascertain the bearing condition.

One of the important issues being explored in Industry 4.0 is collaborative mobile robots. This collaboration requires precise navigation systems, especially indoor navigation systems where GNSS (Global Navigation Satellite System) cannot be used. To enable the precise localization of robots, different variations of navigation systems are being developed, mainly based on trilateration and triangulation methods. Triangulation systems are distinguished by the fact that they allow for the precise determination of an object’s orientation, which is important for mobile robots. An important feature of positioning systems is the frequency of position updates based on measurements. For most systems, it is 10–20 Hz. In our work, we propose a high-speed 50 Hz positioning system based on the triangulation method with infrared transmitters and receivers. In addition, our system is completely static, i.e., it has no moving/rotating measurement sensors, which makes it more resistant to disturbances (caused by vibrations, wear and tear of components, etc.). In this paper, we describe the principle of the system as well as its design. Finally, we present tests of the built system, which show a beacon bearing accuracy of $\Delta \phi$ = 0.51$°$, which corresponds to a positioning accuracy of $\Delta R$ = 6.55 cm, with a position update frequency of $f_{update}$ = 50 Hz.

This paper presents a remote vibration monitoring system for combustion engines, utilising edge computing technology. The proposed solution aims to enhance real-time data processing and reduce latency by performing computations closer to the data source. The system integrates vibration sensor, edge computing units, and potentially cloud-based analytics to provide continuous monitoring and early fault detection. The research discusses the architecture, data acquisition process, and implementation challenges. The experimental results show that analysing the values of specific vibration signal measures can be effective in identifying engine anomalies. The results suggest that edge processing can significantly contribute to the reliability of vibration monitoring in similar applications.

Pulse-width modulation (PWM) and pulse-density modulation (PDM) are widely used in applications where electrical energy is delivered in a pulsed manner. Typical examples include LED (light-emitting diode) control, DC motor control, switched-mode power supplies (SMPS), and electric heating control. However, the pulsed operation of power switches is often associated with significant electromagnetic interference (EMI). As an alternative, stochastic pulse-density modulation (SPDM), also referred to as stochastic signal density modulation (SSDM), can be considered. This technique distributes the energy of generated harmonics over a broader frequency spectrum, thereby reducing the amplitude of individual frequency components. As a result, unwanted frequencies become easier to filter out, mitigating EMI more effectively.

One of the important issues being explored in Industry 4.0 is a collaborative mobile robots. This collaboration requires precise navigation systems, especially indoor navigation systems where GNSS (Global Navigation Satellite System) cannot be used. To enable precise localization of robots, different variations of navigation systems are being developed, mainly based on trilateration and triangulation methods. Triangulation systems are distinguished by the fact that they allow precise determination of an object’s orientation, which is important for mobile robots. An important feature of positioning systems is the frequency of position updates based on measurements. For most systems it is 10-20 Hz. In our work, we propose a high-speed 50 Hz positioning system based on the triangulation method with infrared transmitters and receivers. In addition, our system is completely static, i.e. it has no moving/rotating measurement sensors, which makes it more resistant to disturbances (caused by vibrations, wear and tear of components, etc.). In this paper we describe the principle of the system as well as its design. Finally, we present tests of the built system, which show centimeter positioning accuracy with a position update frequency of 50 Hz.