Search Results (45)

To address the issues of bulky structure and complex transmission systems in current transplanters, a compact, electric-driven automatic transplanter was designed. Using pepper plug seedlings as the test subject, this study investigated plug tray dimensions and planting patterns. According to the design requirement that the width of the single-row transplanter must be less than 62.5 cm, a three-dimensional transplanter model was constructed. The transplanter comprises a coaxially installed dual-layer seedling conveying device and a sector-expanding automatic seedling picking and depositing device. The structural dimensions, drive configurations, and driving forces of the transplanter were also determined. Finally, the circuit and pneumatic system were designed, and the transplanter was assembled. Both bench and field tests were conducted to select the optimal working parameters. The test results demonstrated that the seedling picking and depositing mechanism met the required operational efficiency. In static seedling picking and depositing tests, at three transplanting speeds of 120 plants/min, 160 plants/min, and 200 plants/min, the success rates of seedling picking and depositing were 100%, 100%, and 97.5%, respectively. In the field test, at three transplanting speeds of 80 plants/min, 100 plants/min, and 120 plants/min, the transplanting success rates were 94.17%, 90.83%, and 88.33%, respectively. These results illustrate that the compact, electric-driven seedling conveying and picking and depositing devices meet the operational demands of automatic transplanting, providing a reference for the miniaturization and electrification of transplanters. Full article

This study provides a set of designs, simulations and experiments for developing an actuating method for manual pipettes. The goal is to enable robotic manipulation and automatic pipetting, while using manual pipetting devices. This automation is designed to be used as a flexible alternative tool in small and medium-sized biochemistry laboratories that do not possess proper automated pipetting technology, in order to relieve the lab technicians from the tedious, repetitive and error-prone process of manual pipetting needed for the preparation of biological samples. The selected approach is to use a set of pressure-controlled pneumatic cylinders in order to control the actuation and force of the pipettes’ manual buttons. This paper presents a mechanical design, analysis, pneumatic simulation and functional robotic simulation of the developed device, and a comparison of possible pneumatic solutions is presented to explain the selected actuation method. Remote pneumatic pressure sensing is employed in order to avoid electrical sensors, connectors and wires in the area of the actuators, thus expanding the possibility of working in some electromagnetic-compatible environments and to simplify the connecting and cleaning process of the entire device. A functional simulation is conducted using a combination of software packages: Fluidsim for pneumatic simulation, URSim for robot programming and CoppeliaSim for application integration and visualization. Experimental validation is conducted using off-the-shelf pneumatic components, assembled with 3D-printed parts and mounted onto an existing pneumatic gripper. This complete assembly is attached to an industrial collaborative robot, as an end effector, and a program is written to test and validate the functions of the complete device. The in-process actuators’ working pressure is recorded and analyzed to determine the suitability of the proposed method and pipetting ability. Supplemental digital data are provided in the form of pneumatic circuit diagrams, a robot program, simulation scene and recorded values, to facilitate experimental replication and further development. Full article

This paper presents a new computational library for pneumatic circuits, written in the specialized circuit-oriented language “Modelica”, and executed within an open-source IDE, “OpenModelica”, freely available for downloading on the Internet. The library focuses on the problem of energy efficiency and energy savings (two different concepts, that we intend to clarify in the text). The idea is to use the Modelica scripts to simulate typical circuits, known by their energy-efficient designs. We reason that air throttling within valves is one of the great challenges when it comes to energy losses. Also, we argue that compressed air reuse can be seen as a means of increasing efficiency, basically through replacing air throttling with counter-pressure velocity control. A simplified version of the developed Modelica library is made available to the reader in the ^{Appendix A}, to be used with new scripts and adapted to different realities. In our view, in many situations, open-code Modelica programs may constitute an alternative to proprietary software, where the mathematical models of components are mostly hidden from the end user. Theoretical experiments are carried out, focusing on energy management. The results show that the Modelica library hereby presented is solid, with great prospects of future development. They also show that energy efficiency in pneumatic circuits, at times, comes with the cost of poorly controlled velocity and pressure at the actuator, which requires a careful analysis by the designer, before an actual implementation. Full article

Arterial hypertension is one of the most important public health problems, especially in developed countries. The quality and calibration of blood pressure (BP) equipment used for non-invasive blood pressure (NIBP) measurement are essential to obtain accurate data that support correct medical diagnostics. This paper includes the hardware and software description of a flexible, low-cost and algorithm-independent calibrator prototype that can be used for the static and dynamic calibration of automated blood pressure measuring devices (ABPMDs). In the context of this paper, the meaning of calibrator flexibility is mainly related to its ability to adapt or change easily in response to different situations in terms of the calibration of ABPMDs that can use a variety of calibration settings without the need to use specific oscillometric curves from different ABPMD manufacturers. The hardware part of the calibrator includes mainly an electro-pneumatic regulator, used to generate dynamic pressure signals with arbitrary waveforms, amplitudes and frequencies, a pressure sensor, remotely connected through a pneumatic tube to the blood pressure (BP) cuff, a blood pressure release valve and analog conditioning circuits, plus the A/D converter. The software part of the calibrator, mainly developed in LabVIEW 20, enables the simulation of oscillometric pressure pulses with different envelope profiles and the implementation of the main algorithms that are typically used to evaluate systolic, diastolic and mean arterial pressure values. Simulation and experimental results that were obtained validate the theoretical expectations and show a very acceptable level of accuracy and performance of the presented NIBP calibrator prototype. The prototype calibration results were also validated using a certified NIBP calibrator that is frequently used in clinical environments. Full article

This paper presents a novel soft crawling robot controlled by gesture recognition, aimed at enhancing the operability and adaptability of soft robots through natural human–computer interactions. The Leap Motion sensor is employed to capture hand gesture data, and Unreal Engine is used for gesture recognition. Using the UE4Duino, gesture semantics are transmitted to an Arduino control system, enabling direct control over the robot’s movements. For accurate and real-time gesture recognition, we propose a threshold-based method for static gestures and a backpropagation (BP) neural network model for dynamic gestures. In terms of design, the robot utilizes cost-effective thermoplastic polyurethane (TPU) film as the primary pneumatic actuator material. Through a positive and negative pressure switching circuit, the robot’s actuators achieve controllable extension and contraction, allowing for basic movements such as linear motion and directional changes. Experimental results demonstrate that the robot can successfully perform diverse motions under gesture control, highlighting the potential of gesture-based interaction in soft robotics. Full article

To address the challenges of labor-intensive, inefficient, and inconsistent manual hole sowing and transplanting of Angelica sinensis in rain-fed hilly regions of Northwest China, a pneumatic hole-sowing device was designed based on the principle of electromagnetically controlled, high-speed reciprocating cylinder motion. Considering the agronomic requirements for transplanting mulched Angelica sinensis, the device’s structure and operational parameters were optimized. The key mechanisms involved in hole sowing and seedling placement were analyzed. A pneumatic circuit system, controlled by a relay circuit, was established, and a hole-sowing mechanism with a delayed closure effect was designed. Using the Discrete Element Method (DEM) and Multi-Body Dynamics (MBD) coupling technology, a simulation of the hole-sowing process was conducted to evaluate the device’s performance and its impact on soil disturbance and hole reformation in the seedbed. Prototype device performance tests were conducted, using qualified seeding depth under mulch and hole spacing as indicators. When the theoretical hole spacing was 30 cm and the hole-sowing frequency was 60 plants/(min·row), the soil bin test results indicated a seeding depth qualification rate of 93%, a misalignment rate of 3%, and a spacing qualification rate of 83%; the field test results showed a qualified seeding depth rate under mulch of 96%, the hole misalignment rate was 5%, and the spacing qualified rate was 86%. The pneumatic hole-sowing device’s performance meets the agronomic requirements for vertical transplanting of Angelica sinensis seedlings. This research can serve as a reference for designing planting machinery for rhizomatous medicinal plants. Full article

Pneumatic down-the-hole (DTH) hammer drilling technology has been used extensively in the fields of heat reservoir exploitation and geological exploration owing to its advantages of high efficiency and low pollution. However, the vibration near the bit is up to 40 g while DTH hammer drilling, which significantly affects the performance and longevity of the near-bit measurement while drilling (MWD). To enhance the environmental adaptability of the near-bit MWD in pneumatic DTH operations, a design method for a vibration-damping system based on the parameter optimization of a non-dominated sorting genetic algorithm II (NSGA-II) is proposed in this study. First, the whole structure of the near-bit MWD is designed, including the MWD sub-shell, sensors, measurement circuits, batteries, and connecting structures (the circuit unit). Secondly, this study analyzes the vibration characteristics of the pneumatic DTH hammer near the bit. According to the damping structure, the vibration response model for the circuit unit and the damping model are established. Thirdly, NSGA-II is employed to optimize the parameters of the damping model in terms of the low-frequency, high-intensity vibration characteristics near the bit in pneumatic DTH operations, thereby devising a damping scheme tailored to the unique conditions of DTH hammer drilling. Finally, vibration experiments were conducted to verify the effectiveness of the vibration-damping device. The experimental results indicate that within the vibration frequency range of 5–20 Hz and vibration level of 10–40 g, the peak attenuation rate of the circuit unit is more than 86.446%, and the improvement rate of the vibration stability of the system is more than 75.214%; the anti-vibration performance of the near-bit MWD system in DTH hammer drilling is improved remarkably. This study provides strong technical support for the stability of MWD equipment under such special working conditions. It has broad engineering application prospects. Full article

Electromagnetic actuators, characterized by their lack of pneumatic or hydraulic circuits, rapid response, and ease of control, have the potential to significantly enhance the dynamic performance of automotive active suspensions. However, the complexity associated with their models and the calibration of control parameters hampers the efficiency of control design. To address this issue, this paper proposes a reinforcement learning vibration control strategy for electromagnetic active suspension. Firstly, a half-car dynamic model with electromagnetic active suspension is established. Considering the unknown dynamics of the actuator and its preset convergence performance, an optimal control method based on reinforcement learning is investigated. Secondly, a heuristic PI adaptive dynamic programming algorithm is presented. This method can update to the optimal control solution without requiring model parameters or initial design parameters. Finally, the energy consumption and dynamic performance of this method are analyzed through rapid prototyping control simulation. The results show that the ride comfort of the vehicle suspension can be improved with the given preset convergence rate. Full article

Drawing inspiration from the intricate soft structures found in nature, soft actuators possess the ability to incrementally execute complex tasks and adapt to dynamic and interactive environments. In particular, the integration of sensor data feedback allows actuators to respond to environmental stimuli with heightened intelligence. However, conventional rigid sensors are constrained by their inherent lack of flexibility. The current manufacturing processes for flexible sensors are complex and fail to align with the inherent simplicity of soft actuators. In this study, to facilitate the straightforward and consistent sensing of soft pneumatic actuators, carbon–polydimethylsiloxane (CPDMS) materials were employed, utilizing 3D printing and laser-cutting techniques to fabricate a flexible sensor with ease. The preparation of standard tensile specimens verified that the sensor exhibits a fatigue life extending to several hundred cycles and determined its gauge factor to be −3.2. Experimental results indicate that the sensor is suitable for application in soft pneumatic actuators. Additionally, a printed circuit board (PCB) was fabricated and the piecewise constant curvature (PCC) kinematic method was utilized to enable real-time pose estimation of the soft pneumatic actuator. Compared with computer vision methods, the pose estimation error obtained by the sensing method is as low as 4.26%. This work demonstrates that this easily fabricated sensor can deliver real-time pose feedback for flexible pneumatic actuators, thereby expanding the potential application scenarios for soft pneumatic actuators (SPAs). Full article

In the present paper, the use of programmable microprocessors to develop a computerized stand for the preparation of a mixture of flammable/toxic/explosive gases in order to obtain mixtures at concentrations in explosive range is presented. The operating principle of the stand is based on the mixing of two volumetric flows, controlled with the help of microprocessors, where gases are stored and circulated at atmospheric pressure through cylindrical injectors, driven by stepper motors so that the gas circuit does not require valves. The exit of the stand is a homogenization chamber, with agitator and sensor to confirm the desired concentration of the mixture. This automated stand eliminates mechanical, electric or pneumatic valves from the gas circuits, avoiding elements with high mechanical resistance suitable for high pressures/depressions, removing the possibility of the return of the gas flow, without sensitivity to sudden pressures variations. Full article

The present work investigates a comparative study between mechanical and Imhoflot^TM cells on a mini-pilot scale and the applicability of one self-aspirated H-16 cell (hybrid Imhoflot^TM cell) on an industrial scale on-site. The VM-04 cell (vertical feed to the separator vessel with 400 mm diameter) was fabricated, developed, and examined. The copper flotation experiments were conducted under similar volumetric conditions for both the Imhoflot^TM and mechanical flotation cells keeping the rest of the parameters constant. Further, one H-16 cell was positioned at four different stages in the Gökirmak copper flotation circuit of the Acacia (Türkiye) copper beneficiation plant, i.e., at (i) pre-rougher flotation, (ii) rougher concentrate, (iii) cleaner-scavenger tailing, and (iv) first cleaning concentrate aiming at enhancing the flotation circuit capacity through flash flotation in the rougher stage, reducing copper grade in the final tailing, and increasing cleaning throughput, respectively. Comparative copper flotation tests showed that ultimate recoveries using the Imhoflot^TM and mechanically agitated conventional cells were 94% and 74%, respectively. The industrial scale test results indicated that locating one pneumatic H-16 cell with the duty of pre-floating (also known as flash flotation) led to the enrichment ratio and recovery of 4.84 and 89%, respectively. Positioning the H-16 cell at the cleaner-scavenger tailings could diminish the copper tailings grade from 0.43% to 0.31%. Further, a relatively greater enrichment ratio and copper recovery were obtained using only one Imhoflot^TM cell (1.76 and 64%) in comparison with employing four existing mechanical cells (50 m³, each cell) in series (1.45 and 60%) at the first cleaner stage. Full article

Hydro-pneumatic energy storage is a form of compressed-air energy storage that can provide the long-duration storage required for integrating intermittent renewable energies into electrical power grids. This paper presents results based on numerical modelling and laboratory tests for a kilowatt-scale HPES system tested at the University of Malta. This paper presents measurements of the discharge cycle, in which energy stored in compressed air within a pressure vessel is hydro-pneumatically converted back into electricity via a Pelton turbine and fed into the national electricity grid. The tests were conducted using a hydraulic turbine operated under different fixed-turbine rotational speed settings, with the pressure being allowed to decrease gradually during the HPES system’s discharge cycle. The system’s overall efficiency accounted for flow losses, turbine inefficiencies, and electrical losses. The tests showed that this efficiency was practically independent of the compressed-air pressure of specific water turbine runner speeds, despite the water turbine operating at fixed speeds. A numerical model developed in MATLAB Simulink (R2022a) was also presented for use simulating the hydraulic performance of the system during the discharge cycle. The model used secondary loss coefficients for the hydraulic circuit and derived velocity coefficients from computational fluid dynamics (CFD) for the Pelton turbine nozzle. We achieved very good agreement between the predictions based on numerical modelling and the measurements taken during laboratory testing. Full article

This paper reports on the design, implementation, and characterization of a current-mode analog-front-end circuit for capacitance-to-voltage conversion that can be used in connection with a large variety of sensors and actuators in industrial and rehabilitation medicine applications. The circuit is composed by: (i) an oscillator generating a square wave signal whose frequency and pulse width is a function of the value of input capacitance; (ii) a passive low-pass filter that extracts the DC average component of the square wave signal; (iii) a DC-DC amplifier with variable gain ranging from 1 to 1000. The circuit has been designed in the current-mode approach by employing the second-generation current conveyor circuit, and has been implemented by using commercial discrete components as the basic blocks. The circuit allows for gain and sensitivity tunability, offset compensation and regulation, and the capability to manage various ranges of variations of the input capacitance. For a circuit gain of 1000, the measured circuit sensitivity is equal to 167.34 mV/pF with a resolution in terms of capacitance of 5 fF. The implemented circuit has been employed to measure the variations of the capacitance of a McKibben pneumatic muscle associated with the variations of its length that linearly depend on the circuit output voltage. Under step-to-step conditions of movement of the pneumatic muscle, the overall system sensitivity is equal to 70 mV/mm with a standard deviation error of the muscle length variation of 0.008 mm. Full article

To exploit the energy-saving potential of pneumatic actuator systems, various energy-saving circuits have been developed in recent decades. However, the principle of a pressure-based air supply cut-off has only been considered to a limited extent. This article introduces a possible pneumatic circuit solution for this principle and evaluates it via simulation and measurement of the saving potentials and limits of the developed circuit for typical industrial drive tasks. The conducted investigation shows the suitability of the developed energy-saving circuit, especially for the reduction of the actuator oversizing, achieving energy savings of 71% without performance loss. Conversely, applying this principle to an already well-sized cylinder comes with limitations and requires additional damping. The final economic analysis demonstrates that the application of the circuit could achieve comparatively short amortisation times of approx. 1.9 years for a setup with standard pneumatic components. Full article

SPIRA Coil actuators are formed from thin sheets of PET plastic laminated into a coil shape that unfurls like a “party horn” when inflated, while many soft actuators require large pressures to create only modest strains, SPIRA Coils can easily be designed and fabricated to extend over dramatic distances with relatively low working pressures. Internal metalized PET strips separate in the extended portion of the actuator, creating an electrical circuit with a resistance that corresponds to the actuator length. This paper presents and experimentally validates easy-to-use design models for the actuators’ self-retracting spring stiffness, its pneumatic extension force, and its internal length-sensing electrical resistance. Testing of the self-sensing capabilities demonstrates that the embedded sensor can be used to determine the actuator length with virtually no hysteresis. Feedback control with the resistance-based sensing resulted in length-control errors within 5% of the extended actuator length (i.e., 3 cm of 60 cm). Full article