bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing Sustainability for Manufacturing Performance Assessment
Authors: Mani Mahesh , Madan Jatinder , Lee Jae Hyun , Lyons Kevin , Gupta S. K.
Published: September 2013

Manufacturing industries lack the measurement science and the needed information base to measure and effectively compare performance of manufacturing processes, resources and associated services with respect to sustainability. The current use of ad-hoc methods and tools to assess and describe sustainability of manufactured products do not account for manufacturing processes explicitly and hence results in inaccurate and ambiguous comparisons. Further, there are no formal methods for acquiring and exchanging information that help establish a consolidated sustainability information base. Our goal is to develop the needed measurement science and methodology that will enable manufacturers to evaluate sustainability performance of fundamental manufacturing processes ensuring reliable and consistent comparisons. In this paper, we propose and discuss a methodology for sustainability characterization to bridge the measurement science and the needed information base for sustainable manufacturing. This will set the stage for manufacturers to objectively assess and compare different manufacturing processes for sustainability.
Optimal Design of a River Boat Simulator
Authors: Blanco Juan C. , Rodríguez Carlos F.
Published: September 2013

Motion simulation platforms are mechanical devices designed to replicate the dynamics of a given vehicle. They are very attractive for training individuals such as drivers, pilots or passengers. This paper describes the dimensional synthesis of a river boat simulator that consists of a section of the boat (hull) mounted over a 3 DOF parallel robot with a passive weight compensator (3UPS + PU). Given that the dynamic performance of the robot depends strongly on its geometry, an optimization strategy was applied to find its optimal configuration. The optimization objective was to minimize the dynamic requirements of the driving actuators while accomplishing a typical simulation routine. We present the virtual work formulation of the simulator dynamics, which was previously verified with a multi-body software model. This formulation is used in an optimization methodology based on Genetic Algorithms. Different optimal configurations were found related to the set of constraints and sub-spaces of variables considered by the optimization formulation.
Driveline Configuration Effect on Longitudinal Vectoring of Power Flow Between Drive Wheels and Energy Efficiency in Transport Mode of a 6×6 Terrain Truck
Authors: Vantsevich Vladimir V. , Murphy Dennis , Bortolin Gianantonio
Published: September 2013

In this paper, energy efficiency of a 6×6 terrain truck is analyzed with the focus on the driveline system, i.e., a combination of power dividing units, PDUs, which split/vector power between the drive wheels, determine the wheel circumferential forces and tire slippages and thus influence energy efficiency. An analytical method is presented which allows a user to determine the circumferential wheel forces and tire slippages by compiling constraint equations using characteristics of various PDUs employed in the driveline system. A computational algorithm is presented which integrates the above-mentioned equations of the driveline system with the entire model of the truck. An analysis of the effects of wheel power vectoring on energy efficiency of a 6×6 truck is demonstrated for three PDU configurations.
Rotordynamic Analysis Using the Complex Transfer Matrix
Authors: Varney Philip , Green Itzhak
Published: September 2013

The transfer matrix method is an expedient numerical technique for determining the dynamic behavior of a rotordynamic system (e.g., whirl frequencies, steady-state response to forcing). The typical 8 × 8 transfer matrix suffers from several deficiencies. First, for a system incorporating damping, the method generates a characteristic polynomial of degree 8N for a model of N lumped masses (degree 4N for an undamped model). The high degree of the polynomial results in lengthy computation times and decreased accuracy. Second, as discussed herein, the 8 × 8 formulation fails to distinguish between forward and backward whirl. These deficiencies are overcome by a novel complex-valued state variable redefinition resulting in a 4×4 transfer matrix including external support stiffness and damping. The complex transfer matrix is then modified to account for analysis within a rotating reference frame. Analysis in a rotating reference frame is a judicious means to determine unique system fault characteristics, which serve as a starting point for the development of an on-line fault detection system. Insights into using the complex transfer matrix in a rotating reference frame are discussed. Analytical results in both inertial and rotating reference frames for an overhung rotor model are provided.
Design of a Novel Intelligent Controller for Efficient Power Delivery in Hybrid Vehicles
Authors: Lambert Tim , Biglarbegian Mohammad , Mahmud Shohel
Published: September 2013

This paper presents the development of a novel intelligent controller that improves fuel efficiency in parallel hybrid vehicles. The complexity of parallel hybrid vehicle models makes development of classical controllers which optimize energy usage extremely difficult. Therefore, we introduce a fuzzy controller that uses four inputs: battery state-of-charge, fuel tank fill quotient, vehicle distance-to-goal and driver power demand. The outputs of the controller are on/off states of the battery power supply, generator, and engine. The controller uses these outputs in a hierarchical power distribution scheme that prioritizes the delivery of power by the most efficient drive mechanism. Simulation results show that the controller increases battery usage up to 20% while decreasing fuel consumption. To verify the robustness of the proposed system, white noise is injected to the controller. The results prove that the system is robust to perturbations.
An Automated Kinematic Analysis Tool for Computationally Synthesizing Planar Mechanisms
Authors: Radhakrishnan Pradeep , Campbell Matthew I.
Published: September 2013

This paper presents an implementation of kinematic analysis to evaluate planar mechanisms for use in an automated design process. The existing software available for kinematic analysis require the user to manually input the mechanism for analysis. But in order to computationally synthesize planar mechanisms, it is important to automatically define the boundary conditions and adjust the necessary parameters to evaluate the kinematics of the mechanism in consideration. Currently, there are no kinematic analysis tools available that can be integrated with a design generation tool. One of the reasons is the absence of a method which not only solves the kinematics reliably but is also applicable to generalized n-bar mechanisms. The authors have implemented the instant center method for solving velocities, the vector polygon approach for solving accelerations and the dyadic decomposition method for solving positions. This implementation operates on n-bar mechanisms consisting of four-bar loops and one-degree of freedom on revolute (R), prismatic (P) and revolute-prismatic (R-P) joints. The developed method takes advantage of the concepts in object oriented programming as well as a unique representation based on graph-grammar formalism. This paper describes the methodology used for generalizing kinematic analysis for integration with a concept generator along with examples to validate the implementation.
Optimization of Coupling Ratio and Kinematics of an Underactuated Robot Leg for Passive Terrain Adaptability
Authors: Kanner Oren Y. , Dollar Aaron M.
Published: September 2013

This paper investigates how the passive adaptability of an underactuated robot leg to uneven terrain is affected by variations in design parameters. In particular, the ratio between the joint torques, the ratio between the link lengths, and the initial joint rest angles are varied to determine configurations that allow for maximum terrain roughness adaptability while minimizing the transmission of disturbance forces to the body. The results show that a proximal/distal joint torque coupling ratio of 1.58, proximal/distal leg length ratio of 0.5, and an initial proximal joint angle of −49 degrees maximize the terrain variability over which the robot can remain stable by exerting a near-constant vertical reaction force while minimizing lateral force and moment disturbances. In addition, the spring stiffness ratio allows for a tradeoff to be made between the different performance metrics.
Pantograph Mechanism for Increasing the Working Area in a Haptic Guidance Device for Sketching, Hatching and Cutting Tasks
Authors: Covarrubias Mario , Bordegoni Monica , Cugini Umberto , Gatti Elia , Mansutti Alessandro
Published: September 2013

The paper presents the design, construction, validation and testing of a Haptic Guidance Device whose aim is to provide dynamic assistance while performing manual activities such as drawing, hatching and cutting. A commercial phantom haptic device was modified by adding a pantograph mechanism in order to increase the haptic working area. The force feedback workspace provided by the phantom device is quite limited, 160 W × 120 H mm. This workspace sometimes is not enough to reproduce manual tasks in a large-scale area as is often required in several educational activities (e.g. sketching, hatching and cutting tasks). In this paper is evaluated a low cost solution for increasing the haptic working area provided by the phantom device. The pantograph mechanism has been linked with the haptic device in order to increase the working area in a 2:1 scale. The users hand moves a pen linked to the device through 2D predefined shapes in which the pens position have been tracked in 2D coordinates at 25 kHz in order to record all the data for the posterior analysis. The haptic guidance device is also equipped with a cutting system using hot wire for physically producing the drawn shape as a piece of polystyrene foam. The haptic guidance device has been tested by people with specific disorders affecting coordination such as Down syndrome and mental retardation under the supervision of their teachers and care assistants. The results of the study prove that higher performance levels can be achieved while performing manual tasks as sketching, hatching and cutting operation using the haptic guidance device.
Model Reduction of a Parametrically Excited Drivetrain
Authors: Pumhoessel Thomas , Hehenberger Peter , Zeman Klaus
Published: September 2013

The complexity of engineering systems is continuously increasing, resulting in mathematical models that become more and more computationally expensive. Furthermore, in model based design, for example, system parameters are subject of change, and therefore, the system equations have to be evaluated repeatedly. Hence, there is a need for providing reduced models which are as compact as possible, but still reflect the properties of the original model in a satisfactory manner.

In this contribution, the reduction of differential equations with time-periodic coefficients, termed as parametrically excited systems, is investigated using the method of Proper Orthogonal Decomposition (POD). A reduced model is set up based on the solution of the original system for a certain parametric combination resonance of the difference type, resulting in an additional stability margin of the trivial solution. It is shown that the POD reduced model approximates the stability behavior of the original system much better than a modally reduced model even if system parameters are subject of change.
Kinematics Analysis of a New 3-DOF Rotational Parallel Mechanism
Authors: Chen Ziming , Cao Wen-ao , Huang Zhen
Published: September 2013

In this paper a new rotational parallel mechanism which has three rotational freedoms is studied. This mechanism consists of only revolute joints. In this mechanism, no joints intersect with each other. The constraint and motion properties are analyzed. The inverse kinematics is solved and the orientation workspace is studied. In the end, the relationship between the orientation workspace and the link lengths is shown.
Flutter of Rectangular Plates in Three Dimensional Incompressible Flow With Various Boundary Conditions: Theory and Experiment
Authors: Wang Ivan , Gibbs Samuel C. , Dowell Earl H.
Published: September 2013

The aeroelastic stability of rectangular plates are well-documented in literature for certain sets of boundary conditions. Specifically, wing flutter, panel flutter, and divergence of a plate that is clamped on all sides are well-understood. However, the ongoing push for lighter structures and novel designs have led to a need to understand the aeroelastic behavior of elastic plates for other boundary conditions. One example is NASA’s continuous mold-line link project for reducing the noise generated by commercial transport aircraft during landing; in order to reduce the noise generated by vortex shedding from the trailing edge flap during landing, the project proposes to connect the gap between the trailing edge flap and the rest of the wing with a flexible plate. This paper summarizes the aeroelastic theory, numerical results, and experimental results of a study on the flutter and/or divergence mechanisms of a rectangular plate for different sets of structural boundary conditions. The theory combines a three-dimensional vortex lattice aerodynamic model with a plate structural model to create a high-fidelity frequency domain aeroelastic model. A modular experimental test bed is designed for this study in order to test the different boundary conditions. The test bed is also designed to test different plate thicknesses and sizes with only a small number of modifications. The well-understood boundary conditions are used as test cases to validate the analysis results, and then results of additional configurations that have not been extensively explored are presented. The results of this paper can be used to support the design efforts of projects involving plates or plate-membranes. In addition, the paper adds to the fundamental understanding of plate aeroelasticity and provides a wealth of experimental data for comparison and future validation.
Fields of Application of Coupling a Real NC Control Unit With Virtual Reality Technology
Authors: Klimant Philipp , Puerzel Franziska , Neugebauer Reimund , Kuhl Michael , Wittstock Volker
Published: September 2013

This paper presents an approach on how to combine the advantages of both, the integration of a real NC control unit in the NC simulation as well as the visualization using the Virtual Reality (VR) technology. As a first step it will be described how to establish an effective coupling between a real NC control unit and a virtual machine model. Therefore the setup of the VR simulation environment, like the preparation of the virtual machine model with its kinematic structure, will be presented. Based on this coupling, different fields of application such as detection and prevention of collisions between the machine axes as well as the material removal at the work piece will be described. Finally the use of this coupling for training purposes will be presented.
Numerical Simulation of Pulse Wave Propagation in Arteries With Structured-Tree Outflow Conditions
Authors: Yasuda Kazuma , Kaneko Shigehiko
Published: September 2013

When constructing the one-dimensional systemic artery tree, the Windkessel model based on parameters describing the total resistance and compliance is generally applied as outflow boundary conditions. However, the Windkessel model does not include wave propagation effects, and moreover, it is not obvious how the parameters should be estimated. Hence, the main purpose of this study is to develop an outflow boundary condition based on the underlying physiology of the arterioles, enabling the prediction of blood flow and pressure in the systemic arteries including the arterioles. The obtained numerical results show the followings. Firstly, we verified that applying the structured tree model as an outflow boundary condition can reproduce the essential characteristics of the arterial pulse better than applying the Windkessel model. Secondly, by analyzing the pulse wave velocity in aorta, we found a correlation between pulse wave velocity and the degree of arteriosclerosis which correspond to the clinical observation.
Relative Contact Dynamics and its Application on Manipulator’s Contact Stability Problem
Authors: Liang Jianxun , Ma Ou , Liu Caishan
Published: September 2013

Contact stability is a major concern when the tip of a manipulator contacts with a stiff surface in a manipulation task. Better understanding of the contact dynamics problem can help deal with the contact stability problem. This paper studies the frictional contact problem of manipulators from the perspective of the recent development of relative contact dynamics. With the presented approach, the contact stability of a robot’s tip can be characterized by two critical parameters A and B. It is shown that parameter A depends on the robot’s configuration and friction coefficient only and parameter B is a function of the configuration, speed and the control forces/torques. By examination of the signs of the two parameters, one can determine whether the tip contact is in a stable contact, unstable contact, or separation condition. Such a characterization of the tip contact stability of a manipulator by just examining two parameters provides a new perspective or means for dealing with contact tasks of a manipulator. A simulation example using a planar manipulator is presented to demonstrate the conclusive relationship between the two key parameters and the contact stability conditions.
Identifying Culprits When Probabilistic Verification Fails
Authors: Musliner David J. , Woods Timothy , Maraist John
Published: September 2013

Automatic design verification techniques are intended to check that a particular system design meets a set of formal requirements. When the system does not meet the requirements, some verification tools can perform culprit identification to indicate which design components contributed to the failure. With non-probabilistic verification, culprit identification is straightforward: the verifier returns a counterexample trace that shows how the system can evolve to violate the desired property, and any component involved in that trace is a potential culprit. For probabilistic verification, the problem is more complicated, because no single trace constitutes a counterexample. Given a set of execution traces that collectively refute a probabilistic property, how should we interpret those traces to find which design components are primarily responsible? This paper discusses an approach to this problem based on decision-tree learning. Our solution provides rapid, scalable, and accurate diagnosis of culprits from execution traces. It rejects distractions and accurately focuses attention on the components that primarily cause a property verification to fail.
A Copula Based Sampling Method for Residual Life Prediction of Engineering Systems Under Uncertainty
Authors: Xi Zhimin , Wang Pingfeng
Published: September 2013

The success of health prognostics of engineering systems will allow engineers to shift the traditional breakdown and time based maintenance to the state-of-art predictive and condition-based maintenance. Performing the right type of maintenance activity at the right time will minimize maintenance costs and the downtime of engineering systems. However, techniques and methodologies for health prognostics are typically application-specific. This paper aims at developing a generic real time sensor-based prognostic methodology for predicting residual life of engineering systems by modeling explicit relationship between the failure time and the time realizations at different degradation levels. Specifically, a Copula based sampling method is proposed with four technical components for off-line training and on-line life prediction. First of all, degradation signals are pre-processed to have non-decreasing degradation data sets. Next, degradation data sets are dicretized into a certain number of degradation levels with associated time realizations. Then, explicit statistical dependence modeling between the failure time and the time realizations at different degradation levels is conducted using the Bayesian Copula approach and the semi-Copula model. Finally, probability density function of the failure time and the residual life are efficiently predicted using the sampling method provided that we know some true time realizations at a certain number of degradation levels. Residual life predictions of electric cooling fans are employed to demonstrate the proposed method.
Plant-Limited Co-Design of an Energy-Efficient Counterbalanced Robotic Manipulator
Authors: Allison James T.
Published: September 2013

Modifying the design of an existing system to meet the needs of a new task is a common activity in mechatronic system development. Often engineers seek to meet requirements for the new task via control design changes alone, but in many cases new requirements are impossible to meet using control design only; physical system design modifications must be considered. Plant-Limited Co-Design (PLCD) is a design methodology for meeting new requirements at minimum cost through limited physical system (plant) design changes in concert with control system redesign. The most influential plant changes are identified to narrow the set of candidate plant changes. PLCD provides quantitative evidence to support strategic plant design modification decisions, including tradeoff analyses of redesign cost and requirement violation. In this article the design of a counterbalanced robotic manipulator is used to illustrate successful PLCD application. A baseline system design is obtained that exploits synergy between manipulator passive dynamics and control to minimize energy consumption for a specific pick-and-place task. The baseline design cannot meet requirements for a second pick-and-place task through control design changes alone. A limited set of plant design changes is identified using sensitivity analysis, and the PLCD result meets the new requirements at a cost significantly less than complete system redesign.
A Tablet Based Application for Teaching Function and Exploring Concept Alternatives During Early Design
Authors: Bohm Matt R. , Nagel Robert L. , Shirley Melissa L.
Published: September 2013

This paper describes the design, implementation, and usage of a tablet based application as a mechanism for concept exploration and function realization in early stage design. Specifically, this work reports on the transformation of a methodology, known as Form Follows Form, into an interactive, multi-touch iPad application that can be used to explore concept alternatives and as tool to increase student awareness and recognition of functionality. Users are able to specify an initial concept to an engineering problem by dragging, dropping, and connecting basic components that they envision as a potential solution. The application then leverages a database of reverse engineered products and algorithms to abstract the underlying functionality of the user specified solution. Students can use the abstracted functionality as a baseline for generating concept alternatives on their own, and also, explore concept and component alternatives suggested by the application. The goal of the application is to reduce design fixation and to provide multiple approaches for concept exploration activities.
3D Object Representation for Physics Simulation Engines and its Effect on Virtual Assembly Tasks
Authors: Gonzalez Germanico , Medellin Hugo I. , Lim Theodore , Ritchie James M. , Sung Raymond C. W.
Published: September 2013

Physical based modelling (PBM) uses physics simulation engines (PSE) to provide the dynamic behaviour and collision detection of virtual objects in virtual environments emulating the real world. There exists a variety of PSEs, each one with pros and cons according to the application in which they are employed. Each physics engine uses its proprietary collision detection algorithm. Collision detection is a key aspect of assembly tasks and its performance is dependent on the way virtual objects are represented. In general, objects can be divided into two groups: convex and concave, the latter being the most common and challenging for collision detection algorithms. This study reports on three different methods to represent concave objects. GIMPACT, Hierarchical Approximate Convex Decomposition (HACD) and Approximate Convex Decomposition (ACD), which are evaluated and compared based on their collision detection performances. An exact convex decomposition algorithm, named as ConvexFT, is also proposed and analyzed in this paper. Finally the performance of the three existing methods and the ConvexFT proposed approach are compared in order to assess which model representation algorithm is best suited for haptic-virtual assembly tasks.
Efficient Damping Prediction of Bolted Structures Using Harmonic Balance Method
Authors: Reuss Pascal , Becker Jens , Gaul Lothar
Published: September 2013

In this paper damping induced by extensive friction occurring in the interface between bolted structures is considered by simulations and experiments. A friction damper is attached to a beam-like flexible structure by screws such that the normal force in the interface can be varied by the clamping force of the screws. Contact and friction force parameters are identified by the comparison of simulated and experimentally determined FRFs for a particular normal force. Afterward a prediction of damping for different configurations is established. For simulations a finite element model is used where suitable contact and friction models are implemented. A time simulation of the system is expensive due to the large number of DoFs of the discretized substructures and the required small step size due to the high contact stiffness. Therefore model reduction methods are used. A further reduction of the computation time can be achieved by using the Harmonic Balance Method (HBM) for a direct frequency domain computation of FRFs. This enables an efficient procedure to approximate the reachable damping as well as to search the optimal damper position and the optimal normal force. The dependency of the friction to the vibration amplitude is therefore taken into account. A more detailed investigation of the nonlinear effects, e.g. higher harmonic response, is then accomplished by transient simulations for the optimal configured system in the time domain and the results are compared to experimental results.
A Novel Low Cost Robot for Skill Training in Minimally Invasive Surgery
Authors: Zhang Xiaoli , Nelson Carl A. , Li Songpo , Ridley Rodney , Rukstalis Daniel B.
Published: September 2013

In this paper, a novel simple robotic system is developed for surgical training in minimally invasive surgery (MIS). The robot automatically measures motion data of instruments in real time using internal encoders, without additional sensing mechanisms. Kinematics equations are integrated in the control software to map motor motion to the instrument tip motion. These recorded motion data then can be analyzed in the computer system for objective evaluation using well established criteria. A neural network algorithm is employed in real time as the observer of weight and inertia effects which are compensated through motor control. Experiment results show that this compact robot provides good stability and smooth motion while guiding instruments using surgeon input. The tracking resolution is sufficient for objective evaluation purposes. The robot combines the realistic feel of MIS instruments with the capability of the computer to tabulate objective measures of performance and skill. Its flexibility as a training instrument can be of great benefit in both providing surgeons with much-needed practice and assessing the outcomes of that practice.
Dynamics-Based Health Monitoring of Wind Turbine Rotor Blades Using Integrated Inertial Sensors
Authors: Dana Scott R. , Adams Douglas E.
Published: September 2013

By analyzing the rotor structural dynamic response of a wind turbine, this research aims to improve decision making in operation and maintenance. To illustrate the potential of this measurement technique, a horizontal axis wind turbine test-bed is used to experimentally simulate the rotor structural dynamic response to uniform flow as well as horizontal and vertical shear flow across the rotor plane. The structural dynamic characteristics of the wind turbine rotor are described in the context of modal analysis where each mode of vibration occurs at a particular frequency with a particular modal deflection shape. These deflection shapes facilitate the effectiveness with which a given aerodynamic load couples into the rotor to produce mechanical power in addition to vibrations of the rotor. Operational modal analysis is used to explore the effects of changes in the wind state on the sensitivity of condition monitoring data to two types of damages in the turbine rotor, ice accretion and blade root cracking. Additionally, the degree to which various damage mechanisms can be identified in the presence of yaw and pitch set points is analyzed. It is shown that certain frequencies in the measured response using the flap, edgewise, and span directions of the wind turbine are sensitive to a change in condition of the rotor for use in detecting that type of damage. By analyzing the changes in the modal response amplitudes, the type of damage present in the rotor system can also be classified.
An Admittance Glove Mechanism for Controlling a Mobile Robot
Authors: Ma Zhou , Ben-Tzvi Pinhas
Published: September 2013

This paper presents a bidirectional teleoperation admittance haptic glove (RML glove) which can be used to control mobile robots. The glove receives information from the environment and the internal status of the mobile robot, and generates a force feedback to the operator through the wireless module which in return communicates command signals to the robot. This haptic device is a lightweight and portable actuator system that fits on bare hands, and adds a haptic sense of force feedback to all fingers without constraining their natural movement. An embedded lead screw mechanism provides force feedback that ranges from zero up to 35 N for each finger. Based on this force feedback, the operator can feel what the robot feels (e.g., link torque amount and distance to an obstacle) which enables a smoother and safer human-control of the robot. To evaluate the performance of the haptic glove, a master-slave control experiment based on force feedback between the glove and the mobile robot is conducted. The results demonstrate that the proposed admittance glove can augment tele-presence.
Controllable, High Force Amplification Using Elastic Cable Capstans
Authors: Thomas Gray C. , Gimenez Clayton C. , Chin Erica D. , Carmedelle Andrew P. , Hoover Aaron M.
Published: September 2013

This paper presents the design and experimental characterization of a continuously variable linear force amplifier based on the theory of capstans. In contrast to traditional capstan amplifiers, the design presented here uses an elastic cable, enabling a control actuator to not only continuously clutch output to a rotating drum but also passively declutch by releasing tension. Our experimental results demonstrate successful declutching at all force amplification ratios up to the limit of our experimental apparatus, 21 — significantly higher than previously published values. A system of distributed capstan amplifiers driven by a central torque source with cable engagement switched by lightweight, low torque actuators has potential to reduce the mass of distal actuators and enable more dynamic performance in robotic applications.
The Accessible Region of Space and Workspace for Robots With Intermittent Flight Phases
Authors: Kean Michael , Cipra Raymond J.
Published: September 2013

For traditional robotic chassis driven by wheeled contact with the environment, the accessible region of space can be determined by examining the obstacles that obstruct locomotion. For robots capable of leaving contact with intermittent ballistic flights, the accessible space is not readily apparent. In order to plan robotic exploration in unknown environments, the robot must first have an estimate for the region of space accessible through the use of a ballistic trajectory.

This work defines the region of accessible space for a robot capable of intermittent flight phases. This includes hopping robots, swinging robots, and wheeled robots with the capability of jumping away from contact. The accessible space will also be identified for the case where there are limitations on the direction of actuation.

Since hopping can be used for climbing vertical walls in some instances, a climbing subspace is defined within the accessible space. This subspace is derived and several examples are shown.
Mechanism State Matrices for Spatial Reconfigurable Mechanisms
Authors: Korves Brian A. , Slaboch Brian J. , Voglewede Philip A.
Published: September 2013

This paper improves augmented mechanism state matrices by replacing joint code with screw system notation. The proposed substitution allows for a more specific description of the joints in the mechanism and the capability to describe both spatial and planar mechanisms. Examples are provided which elucidate the proposed approach.
DC Motor Energetics in Redundant Manipulators With Application to Walking Robots
Authors: Roberts Dustyn P. , Kim Joo H.
Published: September 2013

Understanding electrical energy consumption in a robotic system leads to the ability to minimize energy consumption for a given task. This is particularly important for mobile robots and redundant manipulators where extended operating times and non-optimized movement patterns lead to increased operating costs. However, current research shows conflicting formulas for predicting energy consumption in robotic joints driven by DC motors, specifically when negative work is involved. A breakdown of energy consumption for DC motors is introduced with respect to different operating states and phases of positive and negative work. Additionally, the energy consumption of a two degree of freedom manipulator is simulated and verified experimentally. The same task — lowering the manipulator from point a to b in a vertical line — is completed in both elbow up and elbow down configurations to illustrate the difference in energy consumption during a task that consists of mostly negative work. Finally, this energy expenditure equation is extended to a multi degree of freedom simulated humanoid robot to demonstrate validity and generality.
Simple Leg Placement Strategy for a One Legged Running Model
Authors: Sullivan Timothy , Seipel Justin
Published: September 2013

The Spring Loaded Inverted Pendulum (SLIP) model was developed to describe center of mass movement patterns observed in animals, using only a springy leg and a point mass. However, SLIP is energy conserving and does not accurately represent any biological or robotic system. Still, this model is often used as a foundation for the investigation of improved legged locomotion models. One such model called Torque Damped SLIP (TD-SLIP) utilizes two additional parameters, a time dependent torque and dampening to drastically increase the stability. Forced Damped SLIP (FD-SLIP), a predecessor of TD-SLIP, has shown that this model can be further simplified by using a constant torque, instead of a time varying torque, while still maintaining stability.

Using FD-SLIP as a base, this paper explores a leg placement strategy using a simple PI controller. The controller takes advantage of the fact that the energy state of FD-SLIP is symmetric entering and leaving the stance phase during steady state conditions. During the flight phase, the touch down leg angle is adjusted so that the energy dissipation due to dampening, during the stance phase, compensates for any imbalance of energy. This controller approximately doubles the region of stability when subjected to velocity perturbations at touchdown, enables the model to operate at considerably lower torque values, and drastically reduces the time required to recover from a perturbation, while using less energy. Finally, the leg placement strategy used effectively imitates the natural human response to velocity perturbations while running.
Self-Adaptive Underactuated Hybrid Rolling/Walking Locomotion
Authors: Nelson Carl A.
Published: September 2013

In planetary exploration and other similar robotic applications, it is possible to encounter obstacles on multiple scales, making it difficult to design wheeled locomotion that works well for all terrain types. Legged locomotion tends to be less efficient and slower, but allows better obstacle clearance. This paper describes a novel method of achieving robotic locomotion over uneven terrain using a passive underactuation technique. Using planetary gear trains with one input degree of freedom and two output degrees of freedom, the natural obstacle-based locking of select outputs can cause the transition of power through the alternate outputs. By designing the primary outputs as wheels and the secondary outputs as legs with more ground clearance, a naturally adaptive hybrid gait incorporating both rolling and walking can be generated without the need for sophisticated sensing and control. Derivation and simulation validation are presented.
Energy Efficiency of Legged Robot Locomotion With Elastically-Suspended Loads Over a Range of Suspension Stiffnesses
Authors: Ackerman Jeffrey , Da Xingye , Seipel Justin
Published: September 2013

Elastically suspending a load from humans and animals can increase the energy efficiency of legged locomotion and load carrying. Similarly, elastically-suspended loads have the potential to increase the energy efficiency of legged robot locomotion. External loads and the inherent mass of a legged robot, such as batteries, electronics, and fuel, can be elastically-suspended from the robot chassis with a passive compliant suspension system, reducing the energetic cost of locomotion. In prior work, we developed a simple model to examine the effect of elastically-suspended loads on the energy cost of locomotion from first principles. In this paper, we present experimental results showing the energy cost of locomotion for a simple hexapod robot over a range of suspension stiffness values. Elastically-suspended loads were shown to reduce the energy cost of locomotion by up to 20% versus a rigidly-attached load. We compare the experimental results to the theoretical results predicted by the simple model.
Evaluating and Comparing Functional and Geometric Complexity of Products
Authors: Peterson Matthew , Mocko Gregory M. , Summers Joshua D.
Published: September 2013

This paper describes a design exercise that was conducted to investigate what, if any, correlation exists between the functional complexity of a given artifact and its associated physical complexity as defined by design for manufacturing principles. Nine electromechanical consumer products were chosen and evaluated based on function and form. The results of the experiment show that the products demonstrate a significant variability in physical complexity according to design for manufacturing principles for similar if not identical functional complexity. These results demonstrate that function alone is not an adequate way to evaluate the difficulty of realizing a given concept. Performance characteristics of the functional concept must also be considered. The paper concludes with suggestions for future work in order to better understand how performance influences the physical complexity of an artifact.
Representation: Formal Development and Computational Recognition of Localized Requirement Change Types
Authors: Morkos Beshoy , Joshi Shraddha , Summers Joshua D.
Published: September 2013

Requirement change propagation, the process in which a change to one requirement results in additional requirement changes when otherwise this change would not have been needed, occurs frequently and must be managed. Multiple approaches exist, and have been readily published, for predicting requirement change propagation, analyzing change how a change to one requirement may propagate forward to other, related requirements (global level). However, the type of change encountered within a single requirement (localized level) has not been thoroughly studied and could be used to assist in the global analysis of requirement change propagation. This paper seeks to begin to fill this gap by identifying types of change requirements may encounter. By surveying research performed in the realm of requirement change, a taxonomy of change types is developed. To computationally analyze the changes, the localized requirement changes are represented through syntactical elements to identify which requirements’ parts of speech is affected. Using part of speech language rules, the identification of requirement change type is automatically identified. Further, the automatic identification of requirement change type is used to assist in predicting change propagation, a process currently automated. This bridges the gap between localized and global requirement change in an automated, systematic manner.
Prototypes of a Field Disruption Energy Harvester
Authors: El-Rayes Karim , Abdel-Aziz Ahmed , Abdel-Rahman Eihab M. , Mansour Raafat , El-Saadany Ehab
Published: September 2013

Energy harvesting from vibrations offers a prevailing non-traditional energy source. We introduce a novel electromagnetic transduction mechanism that can be used to harvest low-frequency vibrations. The mechanism induces a current in a coil by disrupting the electromagnetic field around the coil. The harvester is composed of a coil wound around track and surrounded by a magnetic field. The coil and magnetic field source remain stationary while a ferromagnetic ball material moves freely along the track cutting the field lines, disrupting the magnetic field, and inducing current in the coil.

We present a prototype and experiments validating our energy harvesting mechanism as well as a model for the energy harvester. We find that our harvester can generate as much as 2mV and 21 μW from base vibrations of 0.9g amplitude. Our harvester demonstrates low-frequency harvesting with a center frequency as low as 9.4 Hz and a 3db harvesting bandwidth as wide as 5.8 Hz.
Reconfiguration Mechanism With Interlocking Geometric Constraints From Puzzles
Authors: Zhang Liping , Dai Jian S.
Published: September 2013

This paper proposes a reconfiguration mechanism modelling for puzzles with its interlocking geometric constraints analysis. Wooden puzzles consisting of interlocking assemebly of notched sticks are often referred to as bar-puzzles, sometime known as the Chinese Puzzles or Chinese Cross. The puzzle with multiple reconfigurable pieces as kinematic links leads to topology arrangements. Although its partition or assembly process can be operated as mechanism motions, there does not appear to be any evidence that the idea of its mechanism property and any configuration analysis originated. To this purpose, this paper set up a static and discrete reconfiguration theory of geometric puzzles for modeling the topology changement as Put Together, Take Apart, Sequential Movement and various others. The partition and assembly process analysis aims to extract the kinematic chains as links and joints. The puzzle unlocking leads to configuration constraints rearrangement problems which accompanying pieces of bars self-grouped as defined reconfiguration links and joints. The mathematical recreation of the mechanism structure stems from its interlocking geometric constraints property. This paper reveals its interlocking property as configuration constraints including many passive constraints and further discloses the mechanism constraints modeling in two different partition methods. The puzzle solutions are first described as reconfigurable topology mechanism and the constrained mobility is analyzed based on an ingenious and distinctive reconfiguration property.
Evolution of Velovations: A Bicycle Design Enterprise in Lieu of Capstone Design
Authors: Gershenson John K.
Published: September 2013

In fewer than three years, Velovations, Michigan Tech’s Bicycle Design Enterprise, has already tallied over twenty industry supported research and development projects. Our students (undergraduate and graduate) and faculty have worked with SRAM, Pearl Izumi, Saris, Cane Creek, Rolf Prima, RockyMounts, World Bicycle Relief, and others in the bicycle industry. We have worked closely with engineers, designers, and executives at these companies to co-create products that are actually coming to the market. Students have become well versed in innovating products from need understanding all the way through to tooling, including invention disclosures, costing, and industrial design. Students have used their backgrounds in Mechanical Engineering, Biomedical Engineering, Electrical Engineering, Mechanical and Electrical Technology, Exercise Science, Computer Science, Computer Engineering, Civil Engineering, and Social Sciences in combination with a structured innovation process that borrows heavily from our undergraduate course in capstone design and our graduate course in design thinking to add value to the bicycle industry.

These three years have led us to a very new model for a design experience; one that is both rewarding for students and faculty and challenging to the status quo of research and student projects at universities. The purpose of this paper is to share lessons learned in our program and look towards replication in other industries.
Optimal Design of Compliant Joint and Gripper for Miniature Robotic Devices: Application to Surgery
Authors: Rotinat-Libersa Christine , Solano Belen
Published: September 2013

In this paper, we present the different steps towards the development of miniature compliant bending joint and gripper with high mechanical performances. These low encumbrance structures (5 mm cross-section) should deliver, with few actuation force, a large output displacement (90° bending, and 60° jaws opening respectively) under large output loads.

Firstly, we describe the theoretical studies that have been investigated in order to optimally dimension these structures. For the bending joint, the design has been inspired from the literature and optimized. For the gripper, a non-intuitive design has been generated using a multi-objective optimal synthesis method. Finally, these compliant structures have been prototyped, and characterized.

As an applicative example, they have been integrated into the end-effector of a surgical instrument. Despite the limited output load performances obtained (12.5 mN.m output torque with a 2.1 N actuation force, and 0.2 N gripping force respectively), these new building blocks demonstrate the ability of millimeter-size robotic devices further miniaturization.
A review of the combined effects of thermal and noise conditions on human performance
Authors: Moscoso Richard A. , Wang Lily M. , Musser Amy
Published: September 2013

Human perception and annoyance due to background noise has been the subject of much research. A great deal of work has also been done to identify conditions that produce an acceptable thermal environment for building occupants. The experience of occupants in indoor environments, however, is much more complex than can be represented by thermal comfort or the acoustic environment in isolation. Occupants normally experience a mix of thermal, auditory, visual, and olfactory stimuli that combines to form an impression of the environment. This paper is specifically interested in how building occupants trade off between acoustic and thermal comfort. Heating, ventilation, and air-conditioning systems in buildings are often adjusted by building users to arrive at a more comfortable temperature, but this change may also produce more noise. Previous studies on the interaction effects between temperature and noise on human performance are reviewed in this presentation, followed by a discussion of the authors’ current work in this area.