1,721,013 research outputs found
A Reconfigurable Differential CMOS RF Energy Scavenger With 60% Peak Efficiency and -21dBm Sensitivity
No full textA differential RF-DC CMOS converter for RF energy scavenging based on a reconfigurable voltage rectifier topology is presented. The converter efficiency and sensitivity are optimized thanks to the proposed reconfigurable architecture. Prototypes realized in 130nm provide a regulated output voltage of ~2V when working at 868MHz, with a -21dBm sensitivity. The circuit efficiency peaks at 60%, remaining above the 40% for a 18dB input power range
Testing Steer-by-Wire Controllers for Off-Highway Vehicles by Hardware-in-the-Loop Experiments
No full textThe control laws and the hardware architecture for the implementation of a steer-by-wire system for off-highway vehicles are proposed. This paper describes how the hardware-independent control laws for the steer-by-wire actuators have been obtained, it explains the motivations for the choice of the force feedback actuator and of the steering rod electro-hydraulic actuator and finally it presents some hardware-in-the-loop simulation results that test the electro-hydraulic rod actuator and the electronic control unit dedicated to the steering rod
Energetic Approach for Steer-by-Wire in Off-highway Vehicles
No full textStarting from an energetic model of a traditional steering system, this paper proposes three different kinds of architecture for the implementation of a steer-by-wire system on off-highway vehicles. The force feedback and the rack hydraulic control cannot be ideal systems and this affects the overall vehicle dynamics, moreover the effects on the vehicle behavior depends on the chosen architecture. The hardware independent approach proposed in the paper drives the definition of the control requirements on the steering wheel control and on the rack control subsystems and it allows to appreciate the effects of the architecture on the implementation of a steer-by-wire system
Self Powered Wireless Sensors for Chassis, Powertrain, Working Equipment and Trailed Implements
No full textPerformance request, needs for fleet management, vehicle safety and diagnosis control strategies, ask for a continuous increase in vehicle functionalities and work variables observability and controllability. Self-powered wireless sensors, capable of collecting the power they consume directly from the vibrations available on the spot, could play a key role in enabling the sensorization of all those parts of heavy duty machines and trailed vehicles which cannot be connected through wires. This paper investigates the applicability of self-powered wireless sensor nodes to heavy duty machinery by analyzing the energy budget which can be reached by these devices in such operating environment. A survey of possible sensor design is presented, to examine the energy requirements for signal transduction and wireless data transmission, and to highlight most relevant design issues affecting power consumption. Two representative case studies are then considered, to estimate with the support of original experimental data the amount of energy that can be generated by placing state-of-the-art off-the-shelf energy transducers on the gearbox of a baler and on the rear chassis of a tractor. By comparing the amounts of generated and required energy, this paper demonstrates the feasibility of self-powered wireless sensors in the context of heavy duty machines
Testing Steer-by-Wire Controllers for Off-Highway Vehciles by Hardware-in-the-Loop Experiments
No full textThe control laws and the hardware architecture for the implementation of a steer-by-wire system for off-highway vehicles are proposed. This paper describes how the hardware-independent control laws for the steer-by-wire actuators have been obtained, it explains the motivations for the choice of the force feedback actuator and of the steering rod electro-hydraulic actuator and finally it presents some hardware-in-the-loop simulation results that test the electro-hydraulic rod actuator and the electronic control unit dedicated to the steering ro
Sperimentando con CANbus - Controllo di un motore brushless con ridondandza statica per applicazioni di force-feedback in sistemi steer-by-wire
No full textIn questo articolo viene proposto un approccio Hardware-in-the-Loop (HIL) per la realizzazione di una architettura preliminare di controllo di force feedback in applicazioni Steer-by-Wire (SBW). Come attuatore è stato scelto un motore brushless. La determinazione della posizione dell’albero motore gioca un ruolo chiave nell’algoritmo di controllo.Per ottenere una posizione affidabile dell’albero motore si è scelto di implementare una classica ridondanza statica tripla (TMR – Triple Modular Redundancy). I segnali provenienti dall’encoder integrato nel motore sono stati elaborati sfruttando tre differenti piattaforme HW: la prima basata su microcontrollore a 8-bit, la seconda basata su microcontrollore a 16-bit mentre la terza sfrutta un modulo software integrato nel tool di sviluppo utilizzato come HW virtuale. La piattaforma di HW virtuale è utilizzata anche come voter. La posizione effettiva dell’albero motore, risultato dell’ algoritmo di voting, è inviata via bus CAN alla piattaforma a 16-bit che implementa l’algoritmo di controllo del motore e genera i segnali PWM necessari all’alimentazione del motore.La comunicazione tra HW virtuale e reale avviene attraverso bus CAN. Esperimenti condotti a diverse baudrates confermano la validità dell’algoritmo di voting implementato, che produce risultati corretti anche in caso di guasto in uno dei moduli dell’architettura TMR e non è influenzato da condizioni di alto carico del bus di comunicazione
Optimized Energy-Aware Wireless System for Identification of the Relative Positioning of Articulated Systems in the Free Space
No full textIn this paper, a low-cost solution to identify the relative positioning of articulated systems in the free space is presented. To prove the effectiveness of the proposed solution, the system has been applied to a real case study of a tractor connected with a baler. Differently from other solutions, the implemented system can monitor the working conditions of the whole machinery while warning the driver when the machinery gets into a dangerous situation. The system is comprised of two wireless devices called Wireless Master Device (WMD) and Wireless End Device (WED) installed on the tractor and on the baler, respectively. To identify instantaneously the dangerous working conditions, each of the two wireless devices exploits a MEMS inertial sensor measuring 3-D linear accelerations and 3-D magnetic fields components integrated in the devices. Very low power consumption has been obtained by exploiting a hardware–software codesign approach implementing an optimized algorithm combined with a smart task manager. Furthermore, a vibrational energy harvester has been designed and integrated on the WED in order to make the device autonomous from an energetic point of view
Wireless sensor systems with energy harvesting capabilities for safety enhancement in agricultural vehicles
No full textThis paper presents an overview of a multi-sensor wireless system applied to agricultural vehicles. The data provided by the different kinds of ad-hoc developed wireless sensors can be used as starting point for the implementation of an automatic system for the active safety enhancement of the vehicles. In order to guarantee a lifetime comparable with the one of the implement or trailer where they are mounted, each sensor has his own energy harvesting system able to gather energy from the vibrations occurring in the environment where the sensor operates
System With RF Power Delivery Capabilities for Active Safety Enhancement in Industrial Vehicles Using Interchangeable Implements
No full textIn this paper, an active system for safety enhancement in industrial and off-highway vehicles using interchangeable implements is presented. The system, applied to the real case study of automatic identification of implements connected to a telehandler, is developed by adopting a hardware–software codesign approach. It is comprised of two devices: the Illuminator-Gateway Device (IGD) and the End Device (ED). Differently from other similar solutions, the system embeds a complete radio frequency (RF) power delivery system that is compliant with the regulations in force in Europe and in North America to extend the battery lifetime of the ED. In particular, the IGD, positioned on the free end of the telescopic arm of the telehandler, supplies the RF energy required for the operations of the ED and acts as a gateway sending the data received from the ED to the other Electronic Control Units (ECUs) of the vehicle. The ED, instead, is mounted on the connected implement, collects the RF energy delivered by the IGD, and wirelessly sends the unique identifier, the key parameters, and the calculated effective working time of the implement. This information can be used by the main ECU of the vehicle for safety-related purposes and programmed maintenance. Experimental results show that the implemented RF power delivery system is able to gather up to 63% of the power required by the ED when it is on duty, thus significantly extending its battery lifetime
- …
