Roy McCann

Event-Based Measurement Updating Kalman Filter in Network Control Systems

An event based measurement updating method is introduced for discrete Kalman filters to estimate the state feedback of Lebesgue sampled data systems. It is proposed that the conventional prediction and the measurement updating stages of discrete Kalman filters are not processed at the same rate. The prediction can be constant but the measurement rate is varied based on Lebesgue sampling. The measurement update portion is executed when an event takes place. The stability of discrete Kalman filters is investigated when the Lebesgue threshold is increased.

Investigation of a Multiple Input Converter for Grid Connected Thermoelectric-Photovoltaic Hybrid System

Hybrid thermoelectric and photovoltaic (TE/PV) systems more effectively convert solar energy into electrical energy by harvesting thermal energy from the heat dissipated from the photovoltaic technology that would otherwise be wasted. This allows a broader spectrum of the solar electromagnetic energy to be converted to electricity through the use of a thermoelectric module integrated with photovoltaic materials. There have not been previously developed circuits to simultaneously convert mixed-source TE/PV devices for electric utility grid interconnection. Challenges associated with grid interfaces include determining optimized configurations that to account for different or mixed TE/PV materials. A Ćuk-Ćuk multiple input converter is presented to accommodate power flow from multiple sources simultaneously or independently.

System Identification for a Model-Based Observer of a Road Roughness Profiler

The increasing numbers of paved roadways throughout the world have motivated the development of automated methods of assessing road pavement conditions. A method of developing an automated profiling vehicle that can rapidly acquire and accurately determine road roughness levels is presented. It is shown that it is important to compensate for the chassis dynamics in order to minimize the effects of suspension system interactions when computing the road roughness level. Experimental results from a prototype vehicle are detailed where the effectiveness of the vehicle design method is demonstrated.

Improved operation of networked control systems using Lebesgue sampling

This paper introduces an improved network communication method for mission-critical real-time computer controlled processes. Based on Lebesgue sampling theory, this method is referred to as the timed event architecture/protocol (TEA/TEP). As an alternative the time-triggered protocol for control (TTP/C), TEP is designed to minimize the number of communication events on a communication bus and thereby reduce the cost and complexity of network control systems. Experimental results for an automated material handling system based on a modified controller area network (CAN 2.0b) protocol with a feedback motion control system are presented. These results demonstrate the benefits of TEP compared to conventional sampled data systems implemented with TTP/C.

Investigation of direct flux measurements in switched reluctance motors

This paper investigates the use embedded magnetic field sensors in estimating the torque produced by a switched reluctance motor. Recent advances in nanomaterials have enabled the development of very compact magnetic field sensors based on the giant magneto resistive (GMR) effect. This provides a direct measurement of internal magnetic flux levels of an electric machine during operation. With this capability, results are applied analytically to a switched reluctance motor to measure the flux distribution across the surface of a stator tooth. This data is then used in a discrete form of the Maxwell stress tensor to approximate the net torque at the motor shaft. Detailed results are given from a finite element study of a commercially produced switched reluctance motor.

Evaluation of a Kalman predictor approach in forecasting PV solar power generation

Increased adoption of solar photovoltaic (PV) generation has motivated the investigation of improved forecasting techniques. This is due to the disruptive nature of variable energy sources on the existing electric utility infrastructure. This research develops a multiple-rate Kalman predictor that provides real-time forecasting of solar PV generation. The proposed method is evaluated on an operational 13 kW PV array installation at fifteen minute intervals using one-minute measurement data. Forecast values are posted once per-hour for a fifteen minute-ahead market scenario. Two designs are compared that contrast the trade-offs of steady-state variance versus transient following capability. Overall experimental results indicate that a multiple-rate Kalman predictor is a promising technique for improved solar PV forecasting.

Evaluation of a battery energy storage system for coordination of demand response and renewable energy resources

Distributed generation often relies upon variable energy sources such as wind and solar. As the adoption of renewable energy increases, this presents a challenge for coordinating the availability of electricity with electrical loads. Energy storage technologies potentially relieve instantaneous imbalances between renewable generation and load demand. Demand response and time-of-use pricing policies are being increasingly adopted as means to further balance generation and demand given constraints on transmission and distribution lines under heavy load conditions. A small scale pilot study was conducted that investigates the interactions of renewable energy sources equipped with battery storage that included utility communication interfacing. Four sites were installed with battery-converter systems with an evaluation that included both commercial and residential applications. The residential applications were equipped with 24 kWh rated battery storage systems with remotely controlled charge and discharge capability. The commercial and light industrial installations were evaluated using 48 kWh battery storage systems. The results using a regional time-of-use pricing structure were analyzed. Results indicate distributed generation with battery storage is positively influenced by demand response and time-of-use pricing.

Improving RFID Read Rate in Metallic Tractor-Trailer Applications

This paper reviews the basics of radio frequency identification technology and the existing uses in commercial vehicle systems. The specific engineering design challenges associated with the metallic environments encountered in commercial applications are discussed. An empirical design method using a variable dielectric thickness is given. Experimental results for the use of RFID in the metallic environment encountered in a commercial vehicle demonstrate the validity of the design method.

Electric motor based steering for jackknife avoidance in large trucks

Electric motor steering systems have recently been introduced for passenger vehicles to improve handling stability under adverse road conditions. A new advanced steering system is examined where the handwheel angle is augmented by an electronically controlled electric motor. This is referred to as active front steering (AFS). Given the increased emphasis on developing hybrid electric-diesel trucks with electric driven accessories, this paper investigates AFS for large trucks to assist in avoiding jackknife and rollover conditions. In order to effectively deploy this technology in commercial fleet operations, emphasis is given to design aspects to minimize the tendency of AFS systems to interfere with the drivers perception of the truck dynamic response.

Jackknife Avoidance in Large Trucks Using Active Front Steering

Active Front Steering (AFS) systems have recently been introduced for passenger vehicles to improve handling stability under adverse road. conditions. AFS provides a mechanism to augment the steering angle with a small displacement actuator. In this configuration, the steering angle of the front wheels is the combined input of the handwheel with an additional small angle component from an electronically controlled actuator. This paper investigates AFS for large trucks to assist in avoiding jackknife conditions. Emphasis is given to design aspects to minimize the tendency of AFS systems to interfere with the drivers perception of the vehicle responsiveness.