Mechanical Engineering Commons^™

One-Class-At-A-Time Removal Sequence Planning Method For Multiclass Classification Problems, Chieh-Neng Young, Chen-Wen Yen, Yi-Hua Pao, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

Using dynamic programming, this work develops a one-class-at-a-time removal sequence planning method to decompose a multiclass classification problem into a series of two-class problems. Compared with previous decomposition methods, the approach has the following distinct features. First, under the one-class-at-a-time framework, the approach guarantees the optimality of the decomposition. Second, for a K-class problem, the number of binary classifiers required by the method is only K-1. Third, to achieve higher classification accuracy, the approach can easily be adapted to form a committee machine. A drawback of the approach is that its computational burden increases rapidly with the number of classes. …

Spatial Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Single Principal Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

By judiciously selecting the admittance of a manipulator, the forces of contact that occur during assembly can be used to guide the parts to proper positioning. This paper identifies conditions for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for cases in which a single feature (vertex, edge, or face) of one part contacts a single feature of the other, i.e., all single principal contact cases. These conditions ensure that the motion that results from frictionless contact always instantaneously reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reducing conditions …

Effect Of Keyswitch Design Of Desktop And Notebook Keyboards Related To Key Stiffness And Typing Force, Marcia J. Bufton, Richard W. Marklin, Mark L. Nagurka, Guy G. Simoneau

Mechanical Engineering Faculty Research and Publications

This study aimed to compare and analyse rubber-dome desktop, spring column desktop and notebook keyboards in terms of key stiffness and fingertip typing force. The spring-column keyboard resulted in the highest mean peak contact force (0.86N), followed by the rubber dome desktop (0.68N) and the notebook (0.59N). All these differences were statistically significant. Likewise, the spring-column keyboard registered the highest fingertip typing force and the notebook keyboard the lowest. A comparison of forces showed the notebook (rubber dome) keyboard had the highest fingertip-to-peak contact force ratio (overstrike force), and the spring-column generated the least excess force (as a ratio of …

A Mass-Spring-Damper Model Of A Bouncing Ball, Mark L. Nagurka, Shuguang Huang

Mechanical Engineering Faculty Research and Publications

The mechanical properties of a vertically dropped ball, represented by an equivalent mass-spring-damper model, are shown to be related to impact parameters. In particular, the paper develops relationships connecting the mass, stiffness and damping of a linear ball model to the coefficient of restitution and the contact time of the ball with the surface during one bounce. The paper also shows that the ball model parameters are functions of quantities readily determined in an experiment: (i) the height from which the ball is dropped from rest, (ii) the number of bounces, and (iii) the time elapsing between dropping the ball …

A Training Sample Sequence Planning Method For Pattern Recognition Problems, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

In solving pattern recognition problems, many classification methods, such as the nearest-neighbor (NN) rule, need to determine prototypes from a training set. To improve the performance of these classifiers in finding an efficient set of prototypes, this paper introduces a training sample sequence planning method. In particular, by estimating the relative nearness of the training samples to the decision boundary, the approach proposed here incrementally increases the number of prototypes until the desired classification accuracy has been reached. This approach has been tested with a NN classification method and a neural network training approach. Studies based on both artificial and …

Working Postures Of Dentists And Dental Hygienists, Richard W. Marklin, Kevin Cherney

Mechanical Engineering Faculty Research and Publications

A joint study was conducted by a manufacturer of dental stools in the Midwest of the United

States and Marquette University to measure the occupational postures of dentists and dental hygienists. The postures of 10 dentists and 10 dental hygienists were assessed using work sampling and video techniques. Postura! data of the neck, shoulders and lower back were recorded from video and categorized into 30-degree intervals: O (neutral posture of respective joint), 30, 60 and 90 degrees. Each subject's postures were observed while they were treating patients during a four-hour period, during which 100 observations of postures were recorded at …

A Mass-Spring-Damper Model Of A Bouncing Ball (Conference Proceeding), Mark L. Nagurka, Shuguang Huang

Mechanical Engineering Faculty Research and Publications

The mechanical properties of a vertically dropped ball, represented by an equivalent mass-spring-damper model, are related to the coefficient of restitution and the time of contact of the ball during one bounce with the impacting surface. In addition, it is shown that the coefficient of restitution and contact time of a single bounce are related to the total number of bounces and the total time elapsing between dropping the ball and the ball coming to rest. For a ball with significant bounce, approximate expressions for model parameters, i.e., stiffness and damping or equivalently natural frequency and damping ratio, are developed. …

Measurement Of Handle Forces For Crimping Connectors And Cutting Cable In The Electric Power Industry, Richard W. Marklin, Lia Lazuardi, Jeremy R. Wilzbacher

Mechanical Engineering Faculty Research and Publications

Overhead and underground line work in the electric power industry is physically very strenuous and can expose workers to musculoskeletal disorders (MSDs), particularly in the upper extremity. Crimping compression connectors—such as sleeve connectors and lugs—and cutting cables are two of the most frequent tasks that line workers perform. Line workers at many utilities in the US crimp connectors and cut cable with long-handled manual tools. However, the actual magnitude of the forces applied to the handles of these tools is not known. The objectives of this laboratory study were to measure the forces applied to the handles of a manual …

Admittance Selection For Force-Guided Assembly Of Polygonal Parts Despite Friction, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

An important issue in the development of force guidance assembly strategies is the specification of an appropriate admittance control law. This paper identifies conditions to be satisfied when selecting the appropriate admittance to achieve force-guided assembly of polygonal parts for multipoint contact with friction. These conditions restrict the admittance behavior for each of the various one-point and two-point contact cases and ensure that the motion that results from contact reduces part misalignment for each case. We show that, for bounded friction and part misalignments, if the identified conditions are satisfied for a finite number of contact configurations and friction coefficients, …

Admittance Selection For Force-Guided Assembly Of Polyhedral Parts In Single-Point Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

The selection of the proper admittance is important in achieving force-guided assembly. This paper identifies procedures for selecting the appropriate spatial admittance to achieve reliable force-guided assembly of polyhedral parts for single-point frictionless contact cases. Sets of conditions that are imposed on the admittance matrix for different types of single-point contact are presented. These conditions ensure that the motion that results from contact reduces part misalignment in the selected contact state. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance also satisfy the conditions at all …

Optimal Design Of Low Order Controllers Satisfying Sensitivity And Robustness Constraint, Mark L. Nagurka, O. Yaniv

Mechanical Engineering Faculty Research and Publications

The set of all stabilizing controllers of a given low order structure that guarantee specifications on the gain margin, phase margin and a bound on the sensitivity corresponds to a region in n-dimensional space defined by the coefficients of the controllers. For several practical criteria defined in the paper it is shown that the optimal controller lies on the surface of that region. Moreover, it is shown how to reduce that region to avoid actuator saturation during operation.

Robust Procedures For Obtaining Assembly Contact State Extremal Configurations, Pan Feng, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Two important components in the selection of an admittance that facilitates force-guided assembly are the identification of: 1) the set of feasible contact states, and 2) the set of configurations that span each contact state, i.e., the extremal configurations. We present a procedure to automatically generate both sets from CAD models of the assembly parts. In the procedure, all possible combinations of principle contacts are considered when generating hypothesized contact states. The feasibility of each is then evaluated in a genetic algorithm based optimization procedure. The maximum and minimum value of each of the 6 configuration variables spanning each contact …

A Vector Quantization Method For Nearest Neighbor Classifier Design, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper proposes a nearest neighbor classifier design method based on vector quantization (VQ). By investigating the error distribution pattern of the training set, the VQ technique is applied to generate prototypes incrementally until the desired classification result is reached. Experimental results demonstrate the effectiveness of the method.

A False Acceptance Error Controlling Method For Hyperspherical Classifiers, Chen-Wen Yen, Chieh-Neng Young, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

Controlling false acceptance errors is of critical importance in many pattern recognition applications, including signature and speaker verification problems. Toward this goal, this paper presents two post-processing methods to improve the performance of hyperspherical classifiers in rejecting patterns from unknown classes. The first method uses a self-organizational approach to design minimum radius hyperspheres, reducing the redundancy of the class region defined by the hyperspherical classifiers. The second method removes additional redundant class regions from the hyperspheres by using a clustering technique to generate a number of smaller hyperspheres. Simulation and experimental results demonstrate that by removing redundant regions these two …

Design Of Pid Controllers Satisfying Gain Margin And Sensitivity Constraints On A Set Of Plants, O. Yaniv, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper presents a method for the design of PID-type controllers, including those augmented by a filter on the D element, satisfying a required gain margin and an upper bound on the (complementary) sensitivity for a finite set of plants. Important properties of the method are: (i) it can be applied to plants of any order including non-minimum phase plants, plants with delay, plants characterized by quasi-polynomials, unstable plants and plants described by measured data, (ii) the sensors associated with the PI terms and the D term can be different (i.e., they can have different transfer function models), (iii) the …

Robust Pi Controller Design Satisfying Sensitivity And Uncertainty Specifications, O. Yaniv, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper presents a control design method for determining proportional-integral-type controllers satisfying specifications on gain margin, phase margin, and an upper bound on the (complementary) sensitivity for a finite set of plants. The approach can be applied to plants that are stable or unstable, plants given by a model or measured data, and plants of any order, including plants with delays. The algorithm is efficient and fast, and as such can be used in near real-time to determine controller parameters (for online modification of the plant model including its uncertainty and/or the specifications). The method gives an optimal controller for …

Sufficient Conditions For Admittance To Ensure Planar Force-Assembly In Multi-Point Frictionless Contact, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

An important issue in the development of force guidance assembly strategies is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for multi-point contact cases. Conditions that restrict the admittance behavior for each of the various types of two-point contact are presented. These conditions ensure that the motion that results from contact reduces part misalignment for each case. We show that, for bounded misalignments, if the conditions are satisfied for a finite number of contact configurations, the conditions ensure that force guidance is achieved for all …

Admittance Selection For Planar Force-Guided Assembly For Single-Point Contact With Friction, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for single-point frictional contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations and a given coefficient of friction /spl mu//sub M/) then the admittance will also ensure that the conditions are satisfied at all intermediate configurations for all coefficients less than /spl mu//sub M/.

Efficient Contact State Graph Generation For Assembly Applications, Feng Pan, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

An important aspect in the design of many automated assembly strategies is the ability to automatically generate the set of contact states that may occur during an assembly task. In this paper, we present an efficient means of constructing the set of all geometrically feasible contact states that may occur within a bounded set of misalignments (bounds determined by robot inaccuracy). This set is stored as a graph, referred to as an Assembly Contact State Graph (ACSG), which indicates neighbor relationships between feasible states. An ACSG is constructed without user intervention in two stages. In the first stage, all hypothetical …

Business Case For Implementing Two Ergonomic Interventions At An Electric Power Utility, Patricia Seeley, Richard W. Marklin

Mechanical Engineering Faculty Research and Publications

Ergonomics analysis of line workers in the electric power industry who work overhead on utility poles revealed some tasks for which less than 1% of the general population had sufficient strength to perform. During a 2-year study, a large Midwestern US electric utility provided a university with a team of represented workers and management. They evaluated, recommended, and monitored interventions for 32 common line worker tasks that were rated at medium to high magnitude of risk factors for musculoskeletal disorders (MSDs). Two of the recommended ergonomic interventions—the battery-operated press and cutter—were selected by the team as having the greatest potential …

Sufficient Conditions Used In Admittance Selection For Force-Guided Assembly Of Polygonal Parts, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Admittance control approaches show significant promise in providing reliable force-guided assembly. An important issue in the development of these approaches is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable force-guided assembly of planar polyhedral parts for single-point contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reduction conditions at a finite number of contact configurations, then the admittance …

Design Of Predictive Controllers By Dynamic Programming And Neural Networks, Chen-Wen Yen, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper proposes a method for the design of predictive controllers for nonlinear systems. The method consists of two phases, a solution phase and a learning phase. In the solution phase, dynamic programming is applied to obtain a closed-loop control law. In the learning phase, neural networks are used to simulate the control law. This phase overcomes the "curse of dimensionality" problem that has often hindered the implementation of control laws generated by dynamic programming. Experimental results demonstrate the effectiveness of the method

Robust Pi Controller Design Satisfying Gain And Phase Margin Constraints, Mark L. Nagurka, O. Yaniv

Mechanical Engineering Faculty Research and Publications

This paper presents a control design algorithm for determining PI-type controllers satisfying specifications on gain margin, phase margin, and an upper bound on the (complementary) sensitivity for a finite set of plants. Important properties of the algorithm are: (i) it can be applied to plants of any order including plants with delay, unstable plants, and plants given by measured data, (ii) it is efficient and fast, and as such can be used in near real-time to determine controller parameters (for on-line modification of the plant model including its uncertainty and/or the specifications), (iii) it can be used to identify the …

A Thermal Time-Constant Experiment, Kyle Ressler, Kyle Brucker, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A simple experiment, well suited for an undergraduate course in mechatronics, is described in which thermal time-constant information is extracted from a heater-blower table-top system. In the experiment, a thermistor measures the temperature of a resistive-heater that is cooled by a blower and a microcontroller is used for data acquisition. The student is asked to determine the thermal time response, and in particular the thermal time-constant of the system, for different blower speeds. The experiment prompts questions about modeling a thermal system, and exposes the student to basic concepts of mechatronics including measurement and data analysis.

Aerodynamic Effects In A Dropped Ping-Pong Ball Experiment, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper addresses aerodynamic modeling issues related to a simple experiment in which a pingpong ball is dropped from rest onto a table surface. From the times between the ball-table impacts, the initial drop height and the coefficient of restitution can be determined using a model that neglects aerodynamic drag. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the importance of accounting for aerodynamic effects. Two nonlinear aerodynamic models are discussed in the context of experimental results.

Sufficient Conditions Used In Admittance Selection For Planar Force-Guided Assembly, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Admittance control approaches show significant promise in providing reliable force-guided assembly. An important issue in the development of these approaches is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for single-point contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that for bounded misalignment, if the conditions are satisfied for a finite number of contact configurations, the system ensures that force guidance is achieved …

A Simple Dynamics Experiment Based On Acoustic Emission, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper describes a simple experiment well suited for an undergraduate course in mechanical measurements and/or dynamics, in which physical information is extracted from an acoustic emission signature. In the experiment, a ping–pong ball is dropped onto a hard table surface and the audio signal resulting from the ball–table impacts is recorded. The times between successive bounces, or “flight times”, are used to determine the height of the initial drop and the coefficient of restitution of the impact. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the use of the coefficient of restitution and …

Multidirectional Compliance And Constraint For Improved Robotic Deburring. Part 2: Improved Bracing, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This two-part paper presents a method for both improving the positioning capability and increasing the effective stiffness (bracing) of a robotic manipulator through multidirectional compliance and constraint. Improved positioning and improved bracing are attained through the effective use of multiple unilateral kinematic constraints in different directions. The companion paper identified how to specify the compliant characteristics of a manipulator so contact forces lead to deflections that eliminate positional misalignments and result in improved relative positioning through force guidance. In this part, we show that the characteristics beneficial to force guidance are the same characteristics that provide improved bracing when partially …

Fostering Strong Interactions Between Industry And Academia, T. R. Kurfess, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper highlights a number of key issues in the development and execution of joint university-industry engineering projects. Government funding reductions have lead to decreased support of university research and economic forces have driven corporations to reduce or eliminate internal R&D centers. These are two driving factors behind the renewed ties between universities and industries. In developing a plan for a joint research project and when working together towards its solution, both sides need to be cognizant of their respective roles to ensure a successful partnership.

Development Of Knowledge-Based Systems For Aluminum Welding, R. J. Napolitano, H. Kulluk, Mark L. Nagurka, R. P. Martukanitz, P. B. Dickerson

Mechanical Engineering Faculty Research and Publications

No abstract provided.