Ali Galip. Ulsoy

Bio: Ali Galip. Ulsoy is an academic researcher from University of Michigan. The author has contributed to research in topics: Control theory & Robust control. The author has an hindex of 23, co-authored 64 publications receiving 1827 citations. Previous affiliations of Ali Galip. Ulsoy include Ford Motor Company.

Method and apparatus for vehicle yaw rate estimation

Abstract: A method is provided for a vehicle yaw rate estimation using two accelerometers and a steer angle sensor. The new method combines two complimentary approaches to yaw rate estimation using accelerometers. A kinematic yaw rate estimate is weighted with a vehicle lateral acceleration at the center of gravity, and steering angle and vehicle forward speed are incorporated into a Kalman filter for estimating vehicle yaw rate based upon the kinematic yaw rate estimate, the lateral acceleration at the center of gravity, the vehicle steering angle, and the vehicle forward speed. The method incorporates use of either one or two accelerometers.

Model Reference Adaptive Force Control in Milling

Abstract: This paper describes the design and implementation of a Model Reference Adaptive Controller (MRAC) for force control in milling. First, previous work in this area is discussed. Results from previous work on the performance of fixed gain process controllers is summarized. The design of an MRAC for force control in milling is described, including a discussion of the implementation issues of noise and com­ putational speed. The adaptive controller was found to perform more satisfactorily than fixed gain controllers, but is difficult to implement and tune, primarily because of the unmodeled dynamics or measurement noise resulting from runout on the mill­ ing cutter. In this problem there was sufficient separation between the noise and the signal frequency that the noise could be filtered. However, the addition of the filter added additional dynamics to the system which reduced the overall performance from that expected from digital simulations. Increasing labor costs and the increasing need for machined parts with high precision, complex geometries has caused a dramatic increase in the number of Numerically Controlled (NC) and Computer Numerically Controlled (CNC) machine tools being used in production. These NC and CNC machine tools have greatly reduced operator input, resulting in signifi­ cant improvements in productivity. However, it has been demonstrated that further improvements can be made by on­ line manipulation of the programmer specified feedrates [1]. This can be done by implementing a process controller which uses some measure of the process (typically cutting force) to adjust the feedrate. The use of such process controllers has resulted in substantial improvements in productivity [2]; however, they have introduced some serious new problems resulting from variations inherent in the cutting process. For­ tunately, these problems can be reduced or eliminated by using ideas from adaptive control theory in the controller design. The purpose of the research reported in this paper is to ex­ amine the application of a model reference adaptive force con­ troller to the milling process. This paper is organized as follows: in the next section previous work is discussed, in­ cluding the development of a process model and a discussion of the effects of process parameter variations on the perform­ ance of fixed gain process controllers. A subsequent section describes the design of a model reference adaptive controller (MRAC) for milling. The implementation of the MRAC, and experimental results are then presented and discussed. Finally, the research is summarized, major conclusions are drawn, and topics for future research are indicated. Previous Research •«. This section discusses the literature pertinent to the applica­ tion of adaptive control to milling. Before a detailed discus­ sion of the literature can be presented, a point of terminology must be clarified.

Control of a Flexible Robot Arm: Experimental and Theoretical Results

Abstract: The operation of high precision robots is severely limited by. their manipulator dynamic deflection, which persists for a period of time after a move is completed. These unwanted vibrations deteriorate the end effector positional accuracy and reduce significantly the robot arm production rate. A “rigid and flexible motion controller” is derived to introduce additional damping into the flexible motion. This is done by using additional sensors to measure the compliant link vibrations and feed them back to the controller. The existing actuators at the robot joints are used (i.e., no additional actuators are introduced). The performance of the controller is tested on a dynamic model, developed in previous work, for a spherical coordinate robot arm whose last link only is considered to be flexible. The simulation results show a significant reduction in the vibratory motion. The important issue of control and observation spillover is examined and found to present no significant practical problems. Partial evaluation of this approach is performed experimentally by testing two controllers, a “rigid body controller” and a “rigid and flexible motion controller,” on a single joint of a spherical coordinate, laboratory robot arm. The experimental results show a significant reduction in the end effector dynamic deflection; thus partially validating the results of the digital simulation studies.

Stability robustness of LQ and LQG active suspensions

Abstract: A two-degree-of-freedom quarter-car model is used as the basis for linear quadratic (LQ) and linear quadratic Gaussian (LQG) controller design,for an active suspension. The LQ controller results in the best rms performance trade-offs (as defined by the performance index) between ride, handling and packaging requirements. In practice, however, all suspension states are not directly measured, and a Kalman filter can be introduced,for state estimation to yield an LQG controller. This paper (i) quantifies the rms performance losses for LQG control as compared to LQ control, and (ii) compares the LQ and LQG active suspension designs,from the point of view of stability robustness

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Dynamics of multibody systems

Abstract: 1. Introduction 2. Reference kinematics 3. Analytical techniques 4. Mechanics of deformable bodies 5. Floating frame of reference formulation 6. Finite element formulation 7. Large deformation problem Appendix: Linear algebra References Index.