Rene Sanchez

Development and Characterization of an Aircraft Aerosol Time-of-Flight Mass Spectrometer

Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies. In addition, real-time source apportionment software allows the immediate identification and classification of individual particles to guide sampling decisions while in the field. The aircraft (A)-ATOFMS was field-tested on the ground during the Study of Organic Aerosols in Riverside, CA (SOAR) and aboard an aircraft during the Ice in Clouds Experiment-Layer Clouds (ICE-L). Initial results from ICE-L represent the first reported aircraft-based single-particle dual-polarity mass spectrometry measurements and provide an increased understanding of particle mixing state as a function of altitude. Improved ion transmission allows for the first single-particle detection of species out to approximately m/z 2000, an important mass range for the detection of biological aerosols and oligomeric species. In addition, high time resolution measurements of single-particle mixing state are demonstrated and shown to be important for airborne studies where particle concentrations and chemistry vary rapidly.

TOPL: TOOLS FOR OPERATIONAL PLANNING OF TRANSPORTATION NETWORKS

TOPL is a suite of software tools for specifying freeway operational improvement strategies, such as ramp metering, demand and incident management, and for quickly estimating the benefits of such improvements. TOPL is based on the macroscopic cell transmission model. The paper summarizes the theory of the cell transmission model and describes the procedure to carry out a TOPL application. The procedure is illustrated for the 26-mile long I-210W freeway in California, whose model is calibrated using loop detector measurements of volume and speed. The measurements show that congestion originates in a bottleneck and moves upstream, as predicted by the theory. The simulations show that appropriate ramp metering can dramatically reduce total congestion delay and mainline travel time.Copyright

Analysis of Queue Estimation Methods Using Wireless Magnetic Sensors

Four queue estimation methodologies were studied with wireless magnetic sensors installed on a single-lane loop on-ramp. Queue length estimation based on (a) occupancy measurements at the ramp entrance, (b) vehicle counts at the on-ramp entrance and exit, (c) speed measurements at the ramp entrance, and (d) vehicle reidentification were considered. These queue estimation methods were evaluated with available raw and processed sensor data retrieved from the test site through mobile data communication and downloaded from a server. The accuracy and reliability of the queue estimation methods were studied with ground truth data obtained from video. Discrepancies between inconsistent sensor and ground truth data were identified and further analyzed with raw data coming directly from the vehicle detection system at the on-ramp. Each of the methods analyzed had deficiencies that needed to be taken into account and compensated for if they were to be used for applications that involved ramp metering with accurate queue control. The worst performance of the queue estimation methods was observed when the on-ramp was under congestion (queue extends around or beyond the ramp entrance). On the basis of the observations at the on-ramp test site, it was also possible to point out some of the main factors that affect the performance of the queue estimation methods.

A mechatronic approach to full sheet control using steer-able Nips

Abstract State of the art high speed color printers require sheets be accurately positioned as they arrive at the image transfer station. To accomplish this goal, a steerable nips mechanism has been designed and built. This mechanism is located upstream from the image transfer station. This steerable nips mechanism allows sheets to be precisely controlled in the longitudinal, lateral, and skew directions. In this paper we present the design, sensing strategy, and a control law based on state feedback linearization. Simulation and experimental results show that the proposed controller is able to correct for paper position errors in the above mentioned directions under the condition that the sheet has nonzero initial and final velocities. The system model is nonlinear and subject to four nonholonomic constraints.

Vehicle re-identification using wireless magnetic sensors: Algorithm revision, modifications and performance analysis

A vehicle re-identification method based on matching vehicle signatures obtained from wireless magnetic sensors was studied on a single lane loop on-ramp. Different modifications were implemented in the algorithm in order to address limitations of the system when vehicles stop/move slowly over the detectors. The original and modified vehicle re-identification algorithm results were compared against ground truth data obtained from video. Based on the ground truth data it was possible to determine the percentage of vehicles that are re-identified and the number of those vehicles that are misidentified as a function of different algorithm parameters. For this analysis, vehicles were divided into two subsets: i) uncongested and ii) congested. The original method mismatched percentage was around or below 15% for the uncongested vehicle subset and between 20% to 60% for the congested one. With the modified method it was possible to improve the matching rate as well as the accuracy of the matching algorithm. For the uncongested subset, the modified method showed a higher vehicle re-identification rate while maintaining the mismatched percentage around or below 8%. The main improvement over the original method was achieved on the congested vehicle subset, since the number of re-identified vehicles was increased over the original method while keeping the mismatched percentage around or below 14%.

Full Sheet Control Using Steerable Nips

This paper describes the mechatronics design, prototype testing, and control of a steerable nips component for paper path mechanisms in high-speed color printers and photocopiers. When placed upstream from the image transfer station along the paper path, this device precisely controls the longitudinal, lateral, and skew directions of papers sheets, as they arrive to the image transfer station. The paper also presents a complete kinematic and dynamic analysis of the paper sheet steering mechanism, which is validated by experimental results. It is shown that the dynamics of a sheet under the control of the steerable nips mechanism are nonlinear and subject to nonholonomic constraints. A feedback linearization control strategy that includes dynamic surface control is developed and implemented to control the sheets position and angular orientation under the condition that the sheets speed in the longitudinal direction remains positive at all times. Experimental results verify that the steerable nips mechanism under the proposed feedback linearization control strategy is able to meet or exceed all design performance requirements for deployment as a component of an actual printer paper path control mechanism.

Convergence Analysis of a Steerable Nip Mechanism for Full Sheet Control in Printing Devices

Current approaches for high speed color printers require sheets be accurately positioned as they arrive to the image transfer station (ITS). This goal has been achieved by designing and building a steerable nip mechanism, which is located upstream from the ITS. This mechanism consists of two rollers that not only rotate to advance the paper along the track, but also steer the paper in the yaw direction. This paper briefly reviews the design and experimental setup of the system, and focuses on the design and analysis of a controller that precisely corrects the lateral, longitudinal, and angular positions of the sheet. The control strategy used is based on linearization by state feedback with the addition of internal loops for the local control of the actuators. This paper also provides a methodology to tune the controller parameters so that the desired performance specifications are met. The success of this mechatronic approach is corroborated through simulation and experimental results, which show that the system is able to correct sheet errors and meet all the performance specifications. DOI: 10.1115/1.3117195

Full Paper Sheet Control Using Hybrid Automata

Some high speed color printers require that the sheets be accurately controlled in order to achieve a precise alignment of colors. To accomplish this goal a steerable nips mechanism has been proposed as the actuator. This steerable nips mechanism allows the sheet to be precisely controlled in longitudinal, lateral and skew directions. In this paper we develop a control strategy based on hybrid automata that precisely controls the position of the sheet. This hybrid control law has four finite states among which the system switches during the trajectories tracking process. Switching from one state to another is necessary since the normal control mode cannot be used when the trajectory being tracked requires the wheels to have zero angular velocity. The proposed controller is able to move the sheet from an initial position at rest to an arbitrary final position also at rest. The system model is nonlinear and subject to four nonholonomic constraints. Two of these constraints come from the fact that the velocities perpendicular to the wheels must be zero, and the other two constraints are due to the no-slip condition.

Hardware-In-The-Loop On-ramp Simulation Tool to Debug and Test the Universal Ramp Metering Software

Abstract An on-ramp simulation system that can be used to debug and test the Universal Ramp Metering Software (URMS) is presented. The tool includes a simple car following microscopic traffic model for the on-ramp and a Controller Interface Device (CID), which interfaces a standard personal computer with a 2070 traffic controller. The CID consists of the low cost and commonly available National Instruments (NI) USB-6501 24-Channel Digital I/O device and a basic circuit that interfaces the 5-Volt TTL logic from the Digital I/O board to the 2070 controller. The resulting hardware-in-the-loop simulation tool systematically reads the phase states from the controller and changes detector states based on the cars trajectories as displayed on the on-ramp simulator. With this tool it is possible to check the performance of the 2070 controller running the URMS as if the traffic controller was operating on a standard on-ramp managed by Caltrans. Finally, the real-time nature of this tool is discussed based on a quantitative analysis of the simulator performance running on the Windows XP operating system.