1,720,985 research outputs found
Design, prototype and experimental validation of innovative manual wheelchairs for everyday life and sport
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Robotics Applied to Precision Agriculture: The Sustainable Agri.q Rover Case Study
No full textThe Agri.q rover for precision agriculture is the main focus of the present paper. After a description of the prototype, a set of experimental results is presented to validate the energetic sustainability of the robot. Characterized by a modular articulated mechanical structure, 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 crop samples. In addition, the rover is equipped with a platform covered with solar panels, whose orientation can be exploited to maximize the efficiency of the energy harvesting, but also to function as a self-leveling landing platform for drones. The design of such a system was mainly driven by particular attention to energy consumption, bearing in mind the main objective of improving the profitability while decreasing the impact of the agricultural processes. In this paper, all these characteristics are described and analyzed in detail, with particular attention to the energy balance of the whole machine deriving from locomotion on different slopes and soils, panels orienting operations, and of course collection of solar energy
Experimental study on a novel manual wheelchair
Full text linkBACKGROUND: Traditional manual wheelchair users suffer from upper limbs injuries due to the propulsion gesture.
OBJECTIVE: This paper presents the experimental activity addressed to define the dynamic characteristics of a novel manual wheelchair. The design and realization of the wheelchair aim to reduce injuries of the upper limbs related to conventional wheelchairs. A new index called Peak Of Force, POF, is defined and applied to the different wheelchair manual propulsion systems.
METHODS: The wheelchair speed and the left and right-hand forces exerted by the user are monitored. The tests have been performed by changing the transmission ratio of the wheelchair and the wheelchair speed.
RESULTS: The indices MEF and FEF are lower than 100% due to the lateral and radial forces for hand-rim wheelchairs and handbikes. For Handwheelchair.Q these indices are equal to 100%. The mean value of index POF for Handwheelchair.Q is 51.75 %, while it is about 42.5% for the hand-rim wheelchair, and 57.6% for the handbike.
CONCLUSIONS: The user forces for Handwheelchair.Q depend on the wheelchair speed and the pulley radius. The larger pulley radius reduces the average and the maximum force. A variable transmission ratio can be implemented on the proposed wheelchair
Optimal Positioning of Mobile Manipulators Using Closed Form Inverse Kinematics
Full text linkMobile manipulators have recently been subject to studies and researches thanks to their augmented mobility and interaction capability. In the precision agriculture field, the development and implementation of such systems can be advantageous in every aspect of the farm activities, e.g. harvesting, pruning, or trimming. This paper presents the implementation of a 7 degree of freedom manipulator upon a mobile rover prototype, designed for precision agriculture, in order to perform grape sampling tasks. While the redundancy of the arm is used to perform off-line collision avoidance with the environment and the mobile base itself, thanks to sampling based path planning methods, a closed form inverse kinematics solution allows to select the posture which maximizes the manipulability index of the manipulator. To do so, base mobility is used to reach the target and properly position the arm. The overall architecture was implemented on the real system and successfully validated through experimental tests
La robotica sposa la sostenibilità: due esempi dal Politecnico di Torino
Full text linkIl robot per l’agricoltura di precisione e la sedia a rotelle robotizzata: due esempi dal Politecnico di Torino di robotica di servizio e sostenibilità. Dagli obiettivi ONU alla progettazione, focus sulle diverse tipologie di robot e i rispettivi tassi di crescita. Da bilanciare sui bisogni di esseri umani e ambient
Data-Driven Analysis of Locomotion for a Class of Articulated Mobile Robots
No full textIn the recent past, the use of autonomous vehicles is becoming of relevant interest in several fields of application. In many cases, the use of articulated structures is preferred to single chassis robots for their peculiar modularity. Such vehicles are often built as an active front module and a rear one that is pulled passively or that can contribute to the vehicle traction when required. Understanding whether this contribution is convenient or not is the main matter of this paper. Two different mobile robots of different scales and purposes are taken into consideration. A dynamic model is presented and analyzed. An experimental validation of the model parameters is also presented in order to make it exploitable as a reliable analysis tool. At last, a simple yet effective actuation law is tested for both the considered robots to evaluate whether the contribution of the back module is beneficial or not to the whole machine maneuverability
Preliminary Observations for Functional Design of a Mobile Robotic Manipulator
Full text linkAn Active Magnetic Bearing (AMB) is a mechatronic system that supports a rotating shaft by means of magnetic levitation. Cone-shaped Active Magnetic Bearings (AMB) can control the rotor motion in the axial and radial directions simultaneously with two bearings in a cone-shaped magnetic core. Although this configuration eliminates a dedicated axial actuator, it complicates the control due to the coupling of the axial and radial actions. Cone-shaped AMBs are nonlinear and unstable in open-loop. However, obtaining a linear plant model is usually preferred to facilitate the control design, as it can exploit classical control theory tools. Nevertheless, the control performance can deteriorate when the plant model is affected by uncertainty. In this context, this paper presents the identification of a linear and multi-variable cone-shaped AMB system using grey-box modeling. Firstly, the plant linear and nonlinear models are presented. Since the cone-shaped AMB has an unstable open-loop nature, a Linear Quadratic Regulator (LQR) is used to stabilize the plant. An experimental campaign is performed to obtain the plant response while applying persistent disturbance currents on each electromagnet. These measurements are then used to carry out the grey-box identification procedure. It is demonstrated that the identified model yields an experimental match improvement up to 10% when compared to the nominal model. This estimated model can be exploited in model-based control approaches to improve system performance
- …
