The aim of this work has been to integrate the Cartesian space together with the kinematics and dynamics spaces of a car-like robot. We propose a new algorithm that obtains a minimum-time solution to ...the optimal motion planning of the vehicle. The new algorithm is based on the combination of cell-mapping and reinforcement-learning techniques. This algorithm can obtain the environment and vehicle parameters from received experience without needing a mathematical model. The algorithm uses a transformation of the cell-to-cell transitions to reduce the time that is spent in the knowledge of the vehicle dynamics and environment. Four state variables have been considered: 1) the velocity of the vehicle; 2) the x Cartesian coordinate; 3) the y Cartesian coordinate; and 4) the orientation of the vehicle. In addition, two different control actions can act on the vehicle: 1) the traction torque that was used for speeding up/braking the vehicle and 2) the steering angle. The results show the applicability of the proposed algorithm in environments with the presence of obstacles.
The PESCA Instrument Control and Acquisition System (PICAS) design, building and tests are presented. The purpose of the PESCA instrument is the study of the Solar Energetic Particles and the ...Anomalous Cosmic Rays. It is, therefore, a satellite on-board instrument. The PICAS is basically a computer, composed of a microprocessor with a memory block and a set of interfaces for the communication with the rest of the instrument and the satellite. The PICAS manages all the comunication processes with the satellite, that comprises the order reception from the ground station, and the telemetry sending, that includes scientific data and housekeeping data. By means of telecommands, the PICAS is completely controllable from the ground. The PICAS is also a reliable data acquisition system that guarantees the correct reception of the Cosmic Rays data collected in the ground.
Low-cost programmable pulse generator for particle telescope calibration Sánchez, S.; González, M.; Seisdedos, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/1999, Letnik:
436, Številka:
3
Journal Article
Recenzirano
In this paper we present a new calibration system for particle telescopes including multipulse generator and digital controller. The calibration system generates synchronized pulses of variable ...height for every detector channel on the telescope. The control system is based on a commercial microcontroller linked to a personal computer through an RS-232 bidirectional line. The aim of the device is to perform laboratory calibration of multi-detector telescopes prior to calibration at accelerator. This task includes evaluation of linearity and resolution of each detector channel, as well as coincidence logic. The heights of the pulses sent to the detectors are obtained by Monte Carlo simulation of telescope response to a particle flux of any desired geometry and composition.
We present a system to analyze the reachability of the human body. The inverse kinematics technique is employed to find which regions of space are reachable using a certain reach strategy. This ...information is stored in a data structure called volume approximation tree (VATree). This tree has proven itself to be an appropriate data structure for two reasons: it provides an efficient representation of the reachable volumes and it reduces the number of inverse kinematics simulations necessary for its construction. Once the VATrees are constructed for the different reach strategies, that information can be used to determine in real time which strategy is most suitable for a given reach task.
An electronics system for low-energy cosmic ion detection has been designed and built. This instrument was designed to he shipped onboard a satellite with a mission to detect solar energetic ...particles (SEP) and to study the anomalous component of cosmic rays. The electronics of the instrument were verified by four functional tests. In the first of these tests, its response to well-known electronic pulses, analogous to those produced in the detectors, was checked. During the second test, the coincidence-anticoincidence performances have been verified. The third test consisted of the calibration of each detector and its corresponding electronics chain with alpha particles from a /sup 241/Am source. All these preliminary tests were carried out in an Alcala University laboratory. The final test was done with nuclear reaction fragments at the VICKSI (Van de Graaff Isochron Cyctotron Kombination fur Schwere Ionen) heavy ion accelerator facility of the Hahn Meitner Institute in Berlin. The trails proved to be successful, with satisfactory results when compared with those achieved by standard nuclear instrumentation.
Detector system for low-energy cosmic ions study del Peral, L.; Medina, J.; Sánchez, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/1995, Letnik:
354, Številka:
2
Journal Article
Recenzirano
A low-energy cosmic ion detector system composed of a telescope and its amplification electronics has been designed and constructed. The detector system is able to detect ions from hydrogen to iron ...in the energy range of 1–50 MeV/nucleon. The amplification electronics has been designed using space components so that its weight, dimensions and power consumption would be small enough to allow the telescope to be used for cosmic ion detection in space aboard a satellite. The system was calibrated in a heavy ion accelerator, and the results show good charge and mass discrimination for the registered ions as well as a good response from the amplification electronics.
The aim of this paper has been to integrate the kinematics and dynamic spaces in only one mathematical model, suitable to employ the cell-mapping technique in order to obtain the minimum-time ...solution to the optimal motion planning of a wheeled mobile vehicle. Through transformation of the cell-to-cell transitions the time spent in the knowledge of the vehicle dynamics and environment has been notably reduced. Four state variables have been considered: the velocity of the vehicle, X and Y Cartesian coordinates and the orientation of the vehicle. Also, two different control actions can act on the vehicle: the traction torque used for speeding up/braking the vehicle and the steering angle. The results show the applicability of the proposed algorithm in environments with presence of obstacles.
New calibration method for charged particles telescopes Martı́n, César; Bronchalo, Enrique; Medina, José ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2002, Letnik:
495, Številka:
3
Journal Article
Recenzirano
A new calibration method for multi-detector telescopes designed to identify energetic ions in the 10
MeV–1
GeV energy range is presented. This method uses a simple and fast numerical technique to ...compare data from calibration experiment on accelerator with data from Monte Carlo simulation of the same experiment. Besides, a numerical technique that relates calibration parameters of successive detectors is presented as well. The quality of the method is tested with experimental data.
In this paper we describe the hardware and software employed to control a solid state telescope particle detector, part of the Russian PHOTON satellite, which is planned to be launched in 1999. The ...development of this kind of instruments has several restrictions due to the special working environment conditions. The solution proposed is based on two hardware modules (analog and digital) and on a control software. There are also shown some of the results obtained on a calibration carried out in the GANIL particle accelerator.
Human reaching in a 3D environment is an interesting matter of research due to its application to workplace or vehicle-interior design. We introduce a 3D environment where a virtual human performs ...reaching tasks over 3D objects in the world. This environment also provides tools to generate and visualize reachable volumes. Reachable spaces are approximated using adjacent box-shaped voxels. We define several strategies in order to model different types of reaching, and we employ our system to construct and analyze reachable spaces for these strategies. In general, different strategies do have reachable spaces that share a common region of intersection. Therefore, goals exists that can be reached using two or more strategies. For those goals, a high-level layer is responsible for selecting the most appropriate given a certain reaching task. As a practical application, this paper presents a comparison of two usual strategies to model standing and seated reaching. The generated reach spaces show that, for each of them, a strategy is clearly more adequate than the other.
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