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The use of robotic technologies for caregiving and assistance has become a very interesting research topic in the field of robotics. Towards this goal, the researchers at Politecnico di Torino are developing robotic solutions for indoor assistance. This paper presents the D.O.T. PAQUITOP project, which aims at developing a mobile robotic assistant for the hospital environment. The mobile robot is composed of a custom omnidirectional platform, named PAQUITOP, a commercial 6 dof robotic arm, sensors for monitoring vital signs in patients, and a tablet to interact with the patient. To prove the effectiveness of this solution, preliminary tests were conducted with success in the laboratories of Politecnico di Torino and, thanks to the collaboration with the Onlus Fondazione D.O.T. and the medical staff of Molinette Hospital in Turin (Italy), at the hematology ward of Molinette Hospital.

The Agri_q is an electric unmanned ground vehicle specifically designed for precision agriculture applications. Since it is expected to traverse on unstructured terrain, especially uneven terrain, or to climb obstacles or slopes, an eight-wheeled locomotion layout, with each pair of wheels supported by a bogie, has been chosen. The wide contact surface between the vehicle and the ground ensures a convenient weight distribution, furthermore, the bogie acts like a filter with respect to ground irregularities, reducing the transmissibility of the oscillations. Nevertheless, this locomotion layout entails a substantial lateral slithering along curved trajectories, which results in an increase of the needed driving torque. Therefore, reducing the number of ground contact points to compare the torque adsorption in different configurations, namely four, six, or eight wheels, could be of interest. This paper presents a reconfiguration mechanism able to modify the Agri_q locomotion layout by lifting one of the two wheels carried by the bogie and to activate, at the same time, a suspension device. The kinematic synthesis of the mechanism and the dynamic characteristics of the Agri_q suspended front module are presented.

In this paper, an innovative UGV (Unmanned Ground Vehicle), named Agri.q, is presented. The rover is specifically designed for precision agriculture applications and is able to work in unstructured environment on irregular soil, cooperating with drones, if necessary. It is equipped with specific tools and sensors to per-form specific tasks, i.e. mapping the field, monitoring the crops and collecting soil and leaf samples. In addition, it is provided with a two degrees of freedom landing platform able to self-orient to ensure a safe drone docking or even to maximize the sunrays collection during the auto-charging phase. In this way, the rover autonomy and sustainability are increased. The functional design of the rover and the design of its actuation system are reported herein; furthermore, the first prototype is described and some preliminary results obtained during experimental tests are discussed.

Precision agriculture is a management strategy aimed at enhancing the productivity, profitability, and sustainability of agricultural production from incorporation of technological advances primarily developed for other industries. Among them, robotics is playing a leading role for it allows monitoring with unprecedented punctuality the number of factors affecting the production processes. In this scenario the researchers at Politecnico di Torino developed an innovative unmanned ground vehicle expressly featured for accomplishment of monitoring tasks, with particular focus on the vine cultivation industry which is peculiarly strong in the region. The rover, named Agri.q, is an eight-wheeled mobile robot whose conceptual design has been already presented to the scientific community. This paper presents the first experimental results gathered on the prototype under different conditions of use, in order to illustrate the actual performance of Agri.q in its work environment.

This paper deals with the experimental evaluation of contact pressure at the interface between an elastomeric rod seal for pneumatic cylinders and its metallic counterpart without interposing any intrusive measuring device. A new test bench, which is able to measure the radial force exerted by a rod seal displaced at constant velocity on a sensorized portion of a cylinder rod over time, was designed and manufactured. The seal was pressurised to reproduce actual working conditions. A data postprocessing methodology was developed for an indirect evaluation of contact pressure starting from the experimental data set of the radial force exerted by the seal on the rod. At first, the measured radial force signal was filtered and properly fitted obtaining a differentiable function; then, contact pressure distribution was computed as a function of radial force time derivative, seal velocity and rod diameter. Preliminary experimental results are presented.

In this paper, an innovative mobile and sustainable robot for precision agriculture, named “Agri.q”, is presented. Characterized by a peculiar mechanical architecture and provided with specific sensors and tools, the Agri.q is able to operate in unstructured agricultural environments in order to fulfill several tasks as mapping, monitoring, and manipulating or collecting small soil and leaf samples. In addition, the rover is equipped with a top platform covered with solar panels, whose orientation can be exploited both to maximize the sunrays collection during the auto-charging phase and to permit a drone landing over a horizontal surface, regardless of the ground inclination. A particular attention to energy consumptions and sustainability has driven the mechanical design of the Agri.q powertrain: the weight reduction results into a limited number of small size locomotion motors, enhancing the importance of the harvested solar energy on the energy balance of the whole system. In this paper, all these characteristics are described and analyzed in detail. Moreover, some preliminary tests aimed at evaluating the energetic behaviour of the rover under different working and weather conditions are presented.

This paper deals with the design of a mechanism able to modify the locomotion layout of a novel UGV (Unmanned Ground Vehicle), named Agri_q, specifically designed for precision agriculture applications. Taking into account that it has to move over an irregular and loose soil, the rover is equipped with eight wheels, each couple supported by a rocker, which ensure a wide contact surface between the vehicle and the ground. A limit of this solution is the substantial lateral slithering occurring when the rover engages curved trajectories, which causes an increase of the needed driving torque. Therefore, reducing the number of ground contact points to compare the torque adsorption in different configurations, namely four, six or eight wheels, could be of interest. The designed mechanism has to lift one of the two wheels connected to the rocker providing at the same time a suspension system to reduce the vibrations transmitted to the sub-chassis. Having analyzed the system requirements, two possible functional solutions are proposed and compared. Finally, the synthesis of the chosen mechanism is presented.

This paper deals with the design of a UGV (unmanned ground vehicle) for precise agriculture applications, named Agri.q02. The UGV can be considered the evolution of a previously presented vehicle, the Agri.q, with a novel layout and extended capabilities. Able to operate in unstructured environments and equipped with solar panels, the UGV permits a UAV (unmanned aerial vehicle) landing and recharging, even when positioned on irregular terrain or steep slopes. These features are provided by a positioning mechanism able to keep the landing platform horizontal above the soil; this mechanism was completely redesigned and its dimensional synthesis is presented herein. Finally, in order to collect ground or leaves’ samples for crop monitoring purposes, the novel version of the rover is also equipped by a robotic collaborative arm with a gripper at its end.

The paper presents the study of a hub+bearing system for tire pressure monitoring and control. The tire pressure control is of importance to improve vehicle safety and dynamic behavior, and to reduce fuel consumption and emissions. This feature becomes fundamental in the development of fully automated self-driving cars, which recently some important Companies started to study and test. Firstly, a commercial version of such a system was studied experimentally to evaluate the air-flow vs. pressure curves. Then, a 2D numerical model of the system, by using the commercial CFD software Fluent, was developed and a good match was found between the numerical and the experimental results. Subsequently, taking into account the most important geometric parameters that could influence the conductance and also considering the constraints connected to the bearing dimensions, different configurations of the hub+bearing system were studied numerically. Finally, to validate the CFD results different modular hub+bearing systems were built and experimentally tested. In this way, the critical zones in terms of pressure or velocity were detected and guidelines for designing a new system were obtained.

Recently, both the academic community and the industry are showing a radical growth of interest in service robotics and the International Federation of Robotic (IFR) reports an increase of the specific market higher than 10%. One of the most interesting branch of service robotics is the agricultural robotics. This work relates with the development of a novel UGV (Unmanned Ground Vehicle), named Agri_q, intended to perform crops monitoring and to permit aerial robots landing, carrying and recharging. At first, the working conditions and the design requirements are specified. Then, both a qualitative and a type synthesis of the rover locomotion system and of the chassis reconfiguration mechanism is performed. Subsequently, a dimensional synthesis focused on the choice of the kinematic pair positions and on the link lengths determination is carried out; the aim is to satisfy the design requirements, taking into account the workspace, the transmission angle, and the transmission ratio. In addition, interference problems and technical feasibility are considered and the number of needed actuators is minimized. Finally, a preliminary design solution, which satisfies the peculiar requirements of this UGV, is presented.

The aim of this work is to present a novel UGV equipped with a collaborative robot arm developed for the agricultural sector. The UGV, named Agri.q02, has eight degrees of freedom that permit to work in unstructured environments. The rover is provided with a landing platform for UAVs and a positioning mechanism is able to keep the platform horizontal above the soil. The robotic system is powered by a 12 V battery and is equipped with solar panels, located on the landing platform. To collect samples for crops monitoring purposes and to cooperate with the drone on the platform, a robot arm will be mounted on the UGV. The manipulator will be placed on the rover with a mechanism that permits to enlarge the workspace of the end effector and to overspread a wide portion of the platform. The solution adopted will be described in detail. Indexes will be given to evaluate performance in terms of actual workspace. Finally, the mechatronic system architecture and the operative modalities of the robotic system will be presented.

A new split and recombine (SAR) passive micromixer, namely the H-C mixer, is presented. The performance of the micromixer is analyzed numerically at Reynolds numbers up to 100, varying the inlet flow-rate ratio. In order to validate the numerical model, tests for an inlet flow-rate ratio of 1 were carried out on the new H-C micromixer along with the established Tear-drop and Chain micromixers for comparison, and good correspondence was found between the differently obtained data. Contrary to the Tear-drop and Chain micromixers, the H-C micromixer exhibited a mixing efficiency greater than 90% independent of Reynolds numbers. In particular, no noticeable dependence on inlet flow-rate ratio was observed. Furthermore, the pressure drop along the H-C mixer was found to be lower than those along the already known mixers.

A methodology to design an air-lubricated piston seal for pneumatic actuators is described. Such a seal permits a small air leakage through a very narrow gap between the seal lip and the counterpart; this air film both avoids contact and ensures lubrication at the seal-counterpart interface thus permitting reduced friction and wear. Subsequently the use of grease could be limited or avoided. A seal geometry equipped with a self-pressurized balancing chamber was designed to make leakage as insensitive as possible to the supply pressure and to the barrel machining tolerances. A prototype was manufactured and tests were carried out.

A novel passive micromixer, denoted as the Y-Y mixer, based on split-and-recombine (SAR) principle is proposed and studied both experimentally and numerically over Reynolds numbers ranging from 1 to 100. Two species are supplied to a prototype via a Y inlet, and flow through four identical elements repeated in series; the width of the mixing channel varies from 0.4 to 0.6 mm, while depth is 0.4 mm. An image analysis technique was used to evaluate mixture homogeneity at four target areas along the mixer. Numerical simulations were found to be a useful support for observing the complex three-dimensional flow inside the channels. Comparison with a known mixer, the tear-drop one, based on the same SAR principle, was also performed, to have a point of reference for evaluating performances. A good agreement was found between numerical and experimental results. Over the examined range of Reynolds numbers Re, the Y-Y micromixer showed at its exit an almost flat mixing characteristic, with a mixing efficiency higher than 0.9; conversely, the tear-drop mixer showed a relevant decrease of efficiency at the midrange. The good performance of the Y-Y micromixer is due to the three-dimensional 90 deg change of direction that occurs in its channel geometry, which causes a fluid swirling already at the midrange of Reynolds numbers. Consequently, the fluid path is lengthened and the interfacial area of species is increased, compensating for the residence time reduction.

An experimental procedure is presented for measuring contact pressure between a pneumatic seal and its counterface. Measurements were performed using pressure-sensitive films, for which a suited calibration procedure was developed, also taking into account humidity influence. Having validated the experimental procedure on a lip seal rectilinear specimen, tests were carried out on commercial piston seals. Results were compared with those coming from numerical simulations performed using a finite-elements analysis.

The design of a bistable electro-pneumatic interface based on laminar-to-turbulent jet transition is herein presented. This principle, used in the past to produce air stream controlled fluidic turbulence amplifiers, is now applied to a new interface driven by acoustic waves and controlled through very low power electrical signals. The study was performed experimentally, attempting to find the optimum interface geometry and analysing its sensitivity to acoustic signals in a frequency range from 2 to 20 kHz and at different excitation levels. A piezo-electric buzzer was used as sound source, resulting in a device with electric power consumption of less than 5 mW, able to switch common low/high pressure pneumatic valves.

In this study, two novel split and recombine (SAR) ‘H-C’ and ‘Y-Y’ micromixers along with a known SAR ‘Chain’ mixer are presented. The efficiency and pressure drop at Reynolds numbers (Re) up to 100 were investigated numerically as well as experimentally. Numerical and experimental values of mixing efficiency and pressure drop coincide considerably, which validate the numerical model. Results show that the mixing efficiency of the Chain mixer is good only at Re≥50 and the pressure drop is relatively high, whereas the H-C and the Y-Y mixers give a mixing efficiency higher than 90% over all the range of Reynolds numbers examined and their energy requirement is less than that of the Chain mixer. Furthermore, numerical residence time distribution (RTD) was explored, which successfully predicts the experimental results.

In this study, a new passive ‘H-C’ micromixer based on the split and recombine (SAR) principle is presented. The design phase was supported by a preliminary numerical analysis of the flow patterns inside the channel to quickly obtain a general idea of mixing of fluids from the distribution of path lines. Then mixing efficiency and pressure drop were investigated numerically as well as experimentally for Reynolds numbers in the range 1–100. At the same time, two known SAR mixers, the Chain and the Tear-drop, were examined to have a point of reference for comparison. Results show that the mixing efficiency of the Tear-drop mixer is good except at the middle range of Reynolds numbers and its pressure drop is high; conversely, the Chain mixer has moderate pressure drop but relatively low mixing efficiency at low and middle range of Reynolds numbers. The H-C mixer shows an almost flat mixing characteristic over the whole range of Reynolds numbers examined and mixing efficiency is higher than 90%. Furthermore, pressure drop within the H-C micromixer, i.e. its energy requirement, is significantly less than that of the Chain and the Tear-drop mixers at the same flow rate.

A numerical analysis on the feeding system of externally pressurised gas bearings, for the correction of the theoretical mass flow rate formula by means of a discharge coefficient, is presented. A flat aerostatic pad with a simple orifice-type feeding system was chosen as case on study, the authors having previously carried out experimental tests on such a prototype. Using the commercial CFD code ANSYS Fluent®, preliminary simulations were carried out on a pad’s geometry using three different flow models. Having selected the flow model able to give the best prediction of the pad’s behaviour in terms of pressure distribution along the air film, additional simulations were carried out on pads with two different diameters of the supply hole, varying the film thickness in a range from 9 to 14 μm. A comparison between numerical and experimental results is presented. In addition, the effect of the flow intake used to perform experimental tests and of the shape of the orifice’s external edge on pressure distribution is analysed.

An experimental methodology aimed at the evaluation of wear in pneumatic seals is presented. New equipment was designed and manufactured in order to measure the radial thickness of worn material on the sealing edge both axially and circumferentially, by means of a laser sensor, as well as to avoid the necessity of disassembling the seals. The methodology is intended as an instrument for a quick comparison of seal prototypes and is proposed as an alternative to those methods that globally quantify the wear of samples by measuring their loss of weight or volume. Results obtained on a NBR commercial lip seal are presented.

The analysis of the airflow from sub-nozzles that have different emitting cross-sections is described. At first, tests were carried out outside the profiled reed and comparison between nozzles was made in terms of air velocity distribution, jet spreading, consumption and exerted drag force. Subsequently, in order to analyze the interaction between the jet emitted by a sub-nozzle and the loom profiled reed, some velocity measurements were repeated inside the weft passage, at various distances from the nozzle exit. Finally, a high-speed camera was used to visualize the weft yarn crossing the weft passage.

The sealing efficiency and the extent of the friction force in an elastomeric seal – counterpart sliding contact depend highly on the contact characteristics at the interface. In particular, a deep knowledge of the interface contact pressure is needed. The work herein described deals with the design of a new test bench for an indirect contact pressure measurement. In particular, the radial force exerted by a rod seal sliding on a sensor-equipped portion of a cylinder rod is measured; during the seal displacement, the contact area between the seal and the sensorequipped rod increases, so that the radial force trend during time can be acquired. Taking the sliding velocity at a low constant value, contact pressure can be indirectly computed by differentiating the force signal. This way it is possible to perform measurements without introducing a third body between the seal and its counterpart, so avoiding any modification of the contact surface. Initially, the test bench working principle is described, highlighting all critical aspects related to the radial force transmission from the seal to the load sensor; subsequently, the test bench requirements were defined. Finally, the design solution was presented.

An experimental methodology is described, conceived to support the design of an air-lubricated lip seal for pneumatic actuators. The aim of the work was to measure the very narrow gap occurring between a new radial sealing device and the counterpart during working conditions, when compressed air in the sealed volume detaches the mating surfaces, causing a small and controlled leakage flow. A spring-energized lip seal, suitably assembled, was chosen as case on study, and a Fizeau interferometer was employed to measure the leakage path thickness. In order to compare leakage data, numerical simulations were carried out by means of a commercial CFD code on the gap geometries defined during experiments. The achieved results are presented.