bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis and Optimal Synthesis of the RSCR Spatial Mechanism
Authors: Ananthasuresh G. K. , Kramer Steven N. 
Published: April 2021

Abstract
The closed form solution of the analysis of the RSCR (Revolute-Spherical-Cylindrical-Revolute) spatial mechanism is presented in this paper. This work is based on the geometric characteristics of the mechanism involving the following three cases: the cone, the cylinder and the one-sheet hyperboloid. These cases derive their names from the nature of the locus of the slider of the linkage as viewed from the output side. Each case is then treated separately to develop a closed form, geometry based analysis technique. These analysis modules are then used to optimally synthesize the mechanism for function, path and motion generation problems satisfying precision conditions within prescribed accuracy limits. The Selective Precision Synthesis technique is employed to formulate the nonlinear inequality constraints. These constraints along with an objective function and other constraints are solved using the Generalized Reduced Gradient method of optimization. In addition, the use of mobility charts is used to aid the designer in making a judicious choice for the initial design point before invoking the optimization method. The determination of the transmission angle for the RSCR mechanism is also described and numerical examples for function, path and motion generation are also included. This new closed form method of analysis based on geometric characteristics is computationally less intensive than other available techniques for spatial mechanism analysis and helps in the visualization of the physical mechanism; something that is not possible with most vector and matrix methods.
Experimental Study of Cardan Joint Dynamics
Authors: Fischer Ian S. , DeWaal Johannes K. 
Published: April 2021

Abstract
An experiment has been conducted indicating invalidity of the assumption of negligible intermediate-joint axial forces in Cardan joint (universal joint) dynamic analysis. It has been observed that increased driveline torque induces the radially-inward deflection of the yoke arms of a Cardan joint, while increased speed will deflect the yoke arms outward. Some suggestions are given to optimize Cardan joints for high torque or high speed.
A Closed-Form Formalism for Controlled and Hybrid Rigid/Elastic Multibody Systems: Part I — Formulation
Authors: Lieh Junghsen , Haque Imtiaz 
Published: April 2021

Abstract
A new formalism leading to closed-form formulation of equations for controlled elastic multibody systems is presented. The method is derived from the virtual work principle and includes the effects of a moving base and rigid body dynamics. The elastic members are treated as Euler-Bernoulli beams and the assumed-mode method is adopted. The equations of motion are expanded in a closed form with a minimum set of variables using the generalized coordinate partitioning and a Jacobian matrix expansion. The inertia matrix, nonlinear coupling vector, generalized force vector and other terms containing the velocity and acceleration effects of a moving base are formulated separately. The formalism facilitates matrix computations and is very suitable for symbolic processing. The method is very systematic and general and can be applied to a multibody system subject to control and constraint conditions. Derivation of the formalism is presented in part I of the article, and symbolic implementation and application of the formalism to various elastic mechanical systems are presented in part II.
A Closed-Form Formalism for Controlled and Hybrid Rigid/Elastic Multibody Systems: Part II — Symbolic Implementation and Applications
Authors: Lieh Junghsen , Haque Imitiaz 
Published: April 2021

Abstract
A program is developed on a DECstation using the symbolic language MAPLE which generates the equations of motion in a closed form and reduces the system order symbolically. A procedure that can make symbolic simplification and linearization is provided. The integration of shape functions is performed symbolically. Both nonlinear and linearized equations of motion with control are established in FORTRAN format. Several models including an elastic vehicle with active suspensions, an elastic robotic manipulator and an elastic slider-crank mechanism with both joint and structural flexibility are generated. Numerical simulation for the active vehicle model using an optimal control strategy is presented. The effect of active suspensions on vehicle and structural vibrations is briefly discussed. A comparison between the nonlinear and linearized robot models is given. Simulation results of the slider-crank mechanism are also presented.
Modeling of Flexible Bodies for Dynamic Analysis of Multi-Body Dynamic Systems Using Ritz Vectors
Authors: Wu Henry T. , Mani Neel K. 
Published: April 2021

Abstract
Vibration normal modes and static correction modes have been previously used to model flexible bodies for dynamic analysis of mechanical systems. The efficiency and accuracy of using these modes to model a system depends on both the flexibility of each body and the applied loads. This paper develops a generalized method for the generation of a set of Ritz vectors to model flexible bodies for dynamic analysis of multi-body mechanical systems. The Ritz vectors are generated using the distribution of dynamic loading on a flexible body. Therefore they form the most efficient vector basis for the spatial distribution of the loadings. The Ritz vectors can be re-generated when the system undergoes significant changes of its configuration and the regeneration procedure is inexpensive. The combinations of vibration normal modes and the proposed Ritz vectors thus form more efficient and accurate vector bases for the modeling of flexible bodies for dynamic analysis.
A Hybrid Integration Scheme for Simulation of Controlled Multibody Mechanical Systems
Authors: Lin Shih-Tin , Lance George M. 
Published: April 2021

Abstract
Simulation of a controlled multibody mechanical system, with a nonstiff mechanical subsystem and a stiff control subsystem, usually suffers from long run time. In this paper, a hybrid integration scheme is proposed to overcome this difficulty. The hybrid integration scheme consists of two parts: a nonstiff integration algorithm for the mechanical subsystem and a stiff integration algorithm for the control subsystem. A double pendulum driven by two AC motors and a backhoe mechanism driven by three hydraulic actuators are used to demonstrate the computational efficiency of the proposed integration scheme.
The Trajectory Analysis of Bevel Planetary Gear Trains
Authors: Lin Chen-Chou , Tsai Lung-Wen 
Published: April 2021

Abstract
In this paper, the trajectory of bevel planetary gear trains has been studied. The parametric equations of trajectory are derived. It is shown that the trajectory generated by a tracer point on the planet of a bevel planetary gear train is analogous to that of a spur planetary gear train. Two cases, gear ratio equal to one and two, are presented in detail including the geometric description, plane of symmetry, extent of trajectory, number of nodes (cusps) and their locations. The criteria for the existence of cusps are verified algebraically, and interpreted from geometrical point of view.
The Design and Analysis of Cam Profiles Using Algebraic Functions
Authors: Blechschmidt James L. , Lee Chung-Hsing 
Published: April 2021

Abstract
A new method for the design and analysis of cam profiles is developed and demonstrated in this paper using algebraic functions in two variables. A technique for the construction of the cam profile directly without using the lift curve is developed. The basis for this analysis is the use of Boolean operators in algebra using a form of algebraic function called the defining function. Using simple quadratic curves such as circles, ellipses, and slabs, more complicated cam profiles are constructed using the Boolean operators of union, intersection, and difference. The resulting closed algebraic curve is converted to the standard implicit form for follower analysis. We show that cam profiles using constraints on the lift at a specific angular rotation can be developed. Examples of all the operations are demonstrated.
Maximum Frequency Design of Prestressed Symmetric, Cross-Ply Laminates of Hybrid Construction
Authors: Duffy K. J. , Adali S. 
Published: April 2021

Abstract
A symmetric, cross-ply laminate of sandwich hybrid construction is optimally designed with the objective of maximizing the fundamental frequency and the separation between two adjacent frequencies. The laminate, which is subject to an in-plane compressive load, is constructed with inner layers made of a low-stiffness material and outer layers made of a high-stiffness material. Optimal hybridization is achieved by determining the optimal ratio of the thickness of the low-stiffness layers to the overall laminate thickness. Moreover, the fibre orientations of high and low stiffness materials (0° or 90°) are determined optimally noting that the orientations of outer and inner layers affect the maximum frequency values in the case of hybrid laminates although they do not have any effect in the case of non-hybrid laminates. Comparative numerical results are given for graphite/glass hybrid and non-hybrid laminates. The optimal value of the hybridization parameter is found to depend on the level of prestress as well as on the aspect ratio. The optimal thicknesses of layers are shown to be non-unique for certain aspect ratios in the case of non-hybrid laminates of a given staking sequence.
Optimal Three Dimensional Robot Path Planning With Collision Avoidance
Authors: Jain Piyush K. , Manoochehri Souran 
Published: April 2021

Abstract
The study reported in this paper deals with path planning in three-dimensional space using network optimization for robotic manipulators working in the presence of obstacles and workspace singularities. To execute the algorithm, the robot design parameters, the geometry and location of the obstacles, and the initial and goal positions of the desired task are required. As a first step, the manipulator workspace is discretized and points inside forbidden regions formed by obstacles and singularities are excluded. An ellipsoidal searchspace is then selected as a part of the workspace to make the network enumeration and path synthesis more efficient. Based on an allowable deviation angle, path segments axe created to form the connectivity network. A path which is optimal with respect to the manipulator kinematic and dynamic properties is generated as a sequence of intermediate points connecting the initial and goal states using Dijkstra’s minimum cost search technique. A computer program has been developed to implement this methodology for three-axis manipulators, and results of the application of this algorithm to some industrial robots are presented.
Analysis to Avoid Interference Between the Links of a Robot With Multiple Arms
Authors: Song Ning , Xu Liju , Sandor George N. , Shieh Ching-Shyong , Weng Tzu-Chen 
Published: April 2021

Abstract
An analytical method to evaluate link interference for a robot with multiple arms is presented with the consideration of shape and volume of links. A simplified geometric model of the links is established. The formulations and criteria to determine link interference are derived accordingly. The algorithm and the flow charts for conducting the analysis of interference between two links are given. The algorithm is applicable to general multiple-arm robots with not only revolute joints, but also prismatic joints. Numerical examples are presented for illustration.
An Algorithm for Real-Time Obstacle Avoidance and Path Planning for Mobile Robots
Authors: Srinivas Y. Lakshmi , Kramer Steven N. 
Published: April 2021

Abstract
This paper presents an extremely fast and reliable sensor-based algorithm that utilizes a combination of optimization techniques and heuristics to accomplish obstacle avoidance and path planning of mobile robots in real-time. This algorithm assumes no previous knowledge of the workspace and is capable of dealing with arbitrarily shaped obstacles with arbitrary motion characteristics. The concept of feasible circle is introduced to determine an obstacle-free subspace around the robot using information which can be obtained from distance sensors. This algorithm employs a unified approach and the modified Lagrange Multiplier method of optimization. A variable penalty, based on the distance of approach is used to keep the robot away from obstacles and the concepts of artificial obstacles and virtual obstacles are introduced to simplify the representation of the known workspace and to control the path of the robot. It is shown that the algorithm is general and can handle concave obstacles, overlapping obstacles, crowded workspaces as well as convex obstacles. The flexibility of the algorithm enables it to be easily integrated with different control strategies. The computational complexity is considerably less than for many existing algorithms, which makes the algorithm attractive for real-time applications. The algorithm is further extended to dynamic obstacles of arbitrary shapes and motion characteristics. Several case studies are presented to illustrate the capabilities of the algorithm.
Modeling of a Two Arm Flexible Robot in Gravity
Authors: Oh Chaeyoun , Vanderploeg Martin J. 
Published: April 2021

Abstract
This paper presents techniques used to model a two arm experimental robot developed at Iowa State University. Both arms are compliant and the robot operates in a vertical plane and is therefore influenced by gravity. The robot is being built to study different control strategies for robots containing compliant members. The system is built with extremely flexible members. This limits the required bandwidth of the control electronics, and mimics the flexible motions that are observed for stiffer faster robots.
The objective of this paper is to develop a reduced order model of the robot system and to experimentally validate the model. Validation requires that the model include gravitational effects. Therefore, an assumed modes model is developed which facilitates modeling of gravitational effects. In order to select the order and mode shapes for the model, an analytical solution is derived for a linearized continuous model. This is compared to the assumed modes model to determine the number of mode shapes needed to model the system. The final model, which includes shortening effects, correlates very well with experimental results.
The Workplace of a General Geometry Planar Three-Degree-of-Freedom Platform-Type Manipulator
Authors: Pennock G. R. , Kassner D. J. 
Published: April 2021

Abstract
This paper focuses on the direct workspace problems of a general geometry fully-parallel-actuated, planar three-degree-of-freedom platform-type manipulator. A set of equations are presented that determine the workspace as a function of the platform orientation. The formulation is governed by the solution to the inverse position problem of the manipulator. The reachable positions of the end-effector point, for a specified platform orientation, are analyzed. To illustrate the concepts, a practical example is included where the end-effector is required to move a cup filled with water. Then the platform orientation, for a specified location of the end-effector point, is studied. If an arbitrary orientation is possible, the specified location of the end-effector point is said to be within the primary workspace. The paper includes a detailed discussion of the total and primary workspaces of the manipulator. The approach adopted here is to regard the manipulator as a combination of three planar, three-revolute open chains. For the sake of completeness, the influence of special manipulator geometry on the workspace is also discussed. Finally, the paper includes the conditions that cause stationary configurations of the manipulator. Insight into these undesirable configurations is provided by a study of the location of the absolute instant center of the platform.
Inverse Kinematic Solutions of Free-Floating Closed-Chain Planar Manipulators
Authors: Agrawal Sunil Kumar , Garimella R. 
Published: April 2021

Abstract
This paper deals with inverse solutions of free-floating closed-chain planar manipulators. The problem, in essence, is to compute the joint angles given the position and orientation of the end-effector. For free-floating planar manipulators, in the absence of external forces and couples, the linear and angular momentum are conserved. This makes the solution procedure and the number of inverse solutions for free-floating manipulators different from those of corresponding fixed-base manipulators.
In order to illustrate this, we present the inverse kinematics of a free-floating planar manipulator whose end-effector is coupled to a base link by two R-R-R series chains. From the analysis, we conclude that for a given position and orientation of the end-effector, the location of the center of mass of the mechanism, and the orientation of the base link, upto 16 solutions of the joint angles are possible. To contrast, a fixed base manipulator of the same structure has a maximum of four solutions.
Modeling and Analysis of Parts Mating in Vibration Assisted Compliant Assembly
Authors: Leu Ming C. , Liu Y. 
Published: April 2021

Abstract
This paper presents the theoretical modeling and parameter analysis of vibration assisted robotic assembly involving peg-in-hole insertion. Transitions among various mating configurations during the vibration assisted insertion are studied. Mating forces and insertion motions are analyzed and numerically simulated. Insertion failure is classified into several types, with the characteristic of each type studied. The types of insertion failure include jamming due to insufficient assembly forces, jamming due to robot deflection, jamming due to assembly geometry restriction, wedging due to compression forces, and peg sliding opposite to the insertion direction. Experiments are performed, where vibration is applied to the hole piece when a SCARA robot is performing peg-in-hole insertion, to verify the analytical results.
On the Automatic Generation of Assembly Sequences for Polyhedral Assemblies
Authors: Beranek John M. , Dutta Debasish 
Published: April 2021

Abstract
We consider the problem of automatically generating all sequences for assembling a product. The individual components of the product are restricted to be polyhedra. Each node of the assembly tree represents a component and every branch from a leaf node to the root of the tree represents a feasible assembly sequence. The capability to generate all feasible assembly sequences, based purely on geometry, is necessary for deriving a good sequence based upon other criteria such as robot motion, fixturing and part stability.
Orientation and Insertion of Randomly Presented Parts Using Vibratory Agitation
Authors: Moncevicz Paul H. , Jakiela Mark J. , Ulrich Karl T. 
Published: April 2021

Abstract
In this article, we propose a new approach to automated assembly. Currently, automated assembly is expensive and difficult because all of the machines required for its implementation impose organization on the parts being assembled. It is this organization that is costly. We investigate an approach that requires less organization and results in assembly as a bulk process. We describe an initial implementation of this approach with a particular parts presentation system. Experiments are performed to determine the part characteristics that promote the success of the implementation. The experimental results are described and future work is suggested.
A Method of Position Sensing for Precision Assembly
Authors: Gurocak H. B. , de Sam Lazaro A. 
Published: April 2021

Abstract
The problem of part mating and assembly with close tolerances or fits has been addressed in the past by active or passive compliance and by force/position control. In this paper a position-sensitive wrist is described. A method is offered to ascertain the position of a peg during an unsuccessful attempt at assembly. The experimental and simulated results of this approach are presented. This work is a part of a research effort in precision assembly using a fuzzy control model.
A Two-Encoder Finger Position Sensing System for a Two-Degree-of-Freedom Robot Hand
Authors: Ng Kim-Gau , Parker Joey K. 
Published: April 2021

Abstract
As part of a robot hand with two independently controlled fingers each having one degree of freedom, a novel two-encoder position sensing system was designed for each of the fingers. In this system, a combination of a linear encoder and a rotary encoder is used to indicate finger position. The linear encoder provides coarse measurements while the rotary encoder provides fine measurements between two adjacent linear encoder counts. This two-encoder system permits more precise measurements than a system with only the linear encoder. The two encoders are connected to an IBM PC through an interface system. This paper presents the complete design and implementation of this two-encoder position sensing system.
An Improved Kinematic Model for Robots and Spatial Mechanisms: Part I — Model Development
Authors: Bodur Ibrahim Niyazi 
Published: April 2021

Abstract
In this paper an improved kinematic modeling method is developed which is applicable to both open and closed kinematic chain topology mechanisms. This methodology is based on relative coordinate frames assigned to the individual links and joints, and the 4 × 4 homogenous transformation matrices between these relative coordinate frames. The homogenous transformation matrices can accommodate the full six degrees-of-freedom necessary in 3-D space. Therefore, this method enables one to develop a kinematic model that corresponds to the actual mechanism. In doing so, the effect of the links and joints are considered separately which will aid one in conceptual and actual development of the model. The method is applied to a Cincinnati-Milacron T3 robot which is a six degree-of-freedom robot with a 3-D spatial serial configuration mechanism made of binary links and one degree-of-freedom joints connecting the links. The results obtained from the methodology developed here are compared to the results of a popular method developed by another researcher.
The methodology developed in this paper is applicable to higher degree-of-freedom joints, up to the full six degrees-of-freedom. It can also be applied to multi-loop mechanisms with the accompanying increase in the complexity of the model. This method helps to reduce the complexity of the problem when one uses the kinematic model of a mechanism in an interference checking, dynamic modeling and simulation, and link flexibility problem. Finally, it is shown that the use of 4 × 4 homogenous transformation matrices do not increase the calculational complexity of the problem appreciably.
An Improved Kinematic Model for Robots and Spatial Mechanisms: Part II — An Exact Kinematic Model of PUMA 560
Authors: Bodur Ibrahim Niyazi 
Published: April 2021

Abstract
In this paper an exact kinematic model of the PUMA 560 is developed. This model is based on the general purpose methodology developed in part one of this paper. Both the forward and inverse kinematic solutions of the PUMA 560 were developed from the model. The values obtained from both of these solutions directly correspond to the values obtained from the controller of the PUMA 560. The complexity of both of these solutions are comparable to the previously published results. This model and solutions demonstrate the applicability of the method developed as well as the availability of both the forward and the inverse solutions from the model.