Spring Damper System Research Articles

Non-periodic motion reduction in globoidal cam with roller follower mechanism

Non periodic motion has been investigated using power spectrum analysis of Fast Fourier Transform (FFT), Lyapunov exponent parameter using Wolf algorithm, and Phase-plane mapping. A multi degrees of freedom (spring-damper system) are added at the end of the follower stem to reduce the nonlinear dynamic behavior of the follower. In the experiment setup, data acquisition technique with signal processing approach is used through an infrared camera device to capture the nonlinear dynamic movement of the follower. A numerical simulation is done using SolidWorks software. An OPTOTRAK/3020 with an infrared camera device is used to track the follower position experimentally. The peak of nonlinear response of the roller follower is reduced by (20.89%, 47.76%, 58.2%, and 67.16%) after using multi degrees of freedom systems.

Surface effect on forced vibration of DNS by viscoelastic layer under a moving load

The surface effect for a forced vibration of a double-nanobeam-system (DNS) coupled by a viscoelastic layer under a moving constant load is studied in this paper. The viscoelastic layer that couples the nanobeams to each other, is modelled as spring-damper system. The Euler- Bernoulli theory and a simply supported boundary condition are considered for both nanobeams. By using the analytical solution, the dynamic displacement is obtained by considering the surface elasticity and residual tension effect on each nanobeams. Furthermore, the several significant parameters such as the velocity of the moving load, spring constant, damping coefficient and also the surface effect have been studied using some plots and examples. Finally, by observing the diagrams it was concluded that as the length of the beams reduces, the surface effect has a considerable effect on each of nanobeams especially at Nano scale, where it was not achieved by classic theories.

Theoretical Analysis and Optimization of a Gloved Hand-Arm System.

Studies have shown that isolators in the form of antivibration (AV) gloves effectively reduce the transmission of unwanted vibration from vibrating equipment to the human hand. However, as most of these studies are based on experimental or modeling techniques, the level of effectiveness and optimum glove properties for better performance remains unclear. To fill this gap, hand-arm system dynamics with and without gloves are studied analytically in this work. In this work, we use a lumped parameter model of the hand-arm system, with hand-tool interaction modeled as a linear spring-damper system. The resulting governing equations of motion are solved analytically using the method of harmonic balance. Parametric analysis is performed on the biomechanical model of the hand-arm system with and without a glove to identify key design parameters. It is observed that the effect of glove parameters on its performance is not repetitive and changes in the studied different frequency ranges. This observation further motivates us to optimize the glove parameters to minimize the overall transmissibility in different frequency ranges.

A Three-Dimensional Mass-Spring Walking Model Could Describe the Ground Reaction Forces

The oscillatory behavior of the center of mass (CoM) and the ground reaction forces (GRFs) of walking people can be successfully explained by a 2D spring-loaded inverted pendulum (SLIP) model. However, the application of the 2D model is just restricted to a two-dimensional plane as the model fails to take the GRFs in the lateral direction into consideration. In this article, we simulated the gait cycle with a nonlinear dynamic model—a three-dimensional bipedal walking model—that compensated for defects in the 2D model. An experiment was conducted to compare the simulation results with the experimental data, which revealed that the experimental data of the ground reaction forces were in good agreement with the results of numerical simulation. A correlation analysis was also conducted between several initial dynamic parameters of the model. Through an examination of the impact of 3D dynamic parameters on the peaks of GRFs in three directions, we found that the 3D parameters had a major effect on the lateral GRFs. These findings demonstrate that the characteristics of human walking can be interpreted from a simple spring-damper system.

Estimating the forcing function in a mechanical system by an inverse calibration method

This article proposes and demonstrates a calibration-based integral formulation for resolving the forcing function in a mass–spring–damper system, given either displacement or acceleration data. The proposed method is novel in the context of vibrations, being thoroughly studied in the field of heat transfer. The approach can be expanded and generalized further to multi-variable systems associated with machine parts, vehicle suspensions, translational and rotational systems, gear systems, etc. when mathematically described by a system of constant property, linear, time-invariant ordinary differential equations. The analytic approach and subsequent numerical reconstruction of the forcing function is based on resolving a parameter-free inverse formulation for the equation(s) of motion. The calibration approach is formulated in the frequency domain and takes advantage of several observations produced by the dimensionality reduction leading to an algebratized system involving an input–output relationship and a transfer function possessing all the system parameters. The transfer function is eliminated in lieu of experimental data, from a calibration effort, thus leading to a reduction of systematic errors. These parameter-free, reduced systematic error aspects are the distinct and novel advantages of the proposed method. A first-kind Volterra integral equation is formed containing only the unknown forcing function and experimental data. As with all ill-posed problems, regularization must be introduced for system stabilization. A future-time technique is instituted for forming a family of predictions based on the chosen regularization parameter. The optimal regularization parameter is estimated using a combination of phase–plane analysis and cross-correlation principles. Finally, a numerical simulation is performed verifying the proposed approach.

Modeling of Visco-Elastic Environments for Humanoid Robot Motion Control

This manuscript presents a model of compliant contacts for time-critical humanoid robot motion control. The proposed model considers the environment as a continuum of spring-damper systems, which allows us to compute the equivalent contact force and torque that the environment exerts on the contact surface. We show that the proposed model extends the linear and rotational springs and dampers - classically used to characterize soft terrains - to the case of large contact surface orientations. The contact model is then used for the real-time whole-body control of humanoid robots walking on visco-elastic environments. The overall approach is validated by simulating walking motions of the iCub humanoid robot. Furthermore, the paper compares the proposed whole-body control strategy and state of the art approaches. In this respect, we investigate the terrain compliance that makes the classical approaches assuming rigid contacts fail. We finally analyze the robustness of the presented control design with respect to non-parametric uncertainty in the contact-model.

Position/force modeling and analysis of a piezo-driven compliant micro-gripper considering the dynamic impacts of gripping objects

The compliant micro-gripper driven by piezo actuator has emerged as a representative end-effector in micro-manipulations. To achieve high performance gripping of tiny and fragile objects, the switched position/force modeling approach has been well explored for such systems. In the present work, we investigate a lever-bridge-lever type piezo-driven compliant micro-gripper and develop a new position/force model to describe both kineto-statics and dynamics of the micro-gripper, where the free motion and gripping motion states in the manipulation process are unified in the modeling approach. In particular, the impacts of gripping objects on the dynamic properties of the gripper (in gripping motion state) are incorporated by considering the gripping object as a spring-damper system with a characteristic length. With this, the dynamic model can better predict the position of the gripping jaw and the contact position of the object, as well as the force applied on the object, which also offers the capability to estimate the stiffness of unknown objects in manipulations. Various gripping experiments with soft and stiff objects of different dimensions are conducted, which demonstrate the effectiveness and accuracy of the proposed modeling approach.

Theoretical and experimental investigations of mechanical vibrations of hot hammer forging

The characterization of mechanical vibrations in a hammer forging process is a tremendously important parameter for machine design and production engineering. The dynamic response of a forging hammer to the reaction forces is affected by material behaviour, time, spring-damper system and foundation. In this research firstly, the effect of mass ratio and coefficient of restitution on the forging efficiency were theoretical characterized. The interesting influence of anvil initial velocity on the forging efficiency is also analytically presented. The mechanical vibrations of a LASCO HO U-315 hammer were experimentally investigated. Two steel grades a S355 and a 42CrMo4 were used to forge trial parts. The velocity of the ram and acceleration of the anvil during a hot die forging process were measured using a laser velocity meter type LSV-2000-45. The influences of forging time, coefficient of restitution, energy loss and time interval (delay) between blows on the efficiency of the forging process were examined. The energy loss before die contact was determined to be approximately 10%. The investigations also showed that a variation of the time interval between blows within the usual range has no effect on the intensity of the vibrations of the anvil nor on the energy loss of the hammer. The dependence of the free damped vibrations of the anvil on machine stiffness, damper coefficient and mass of machine has been confirmed. Additionally, the loss of energy due to hammer movement as well as the free damped mechanical vibrations of the anvil were theoretically analysed in order to verify the experimental findings. Theoretical analysis showed an anvil initial velocity of approximately 0.2 m/s results in a 4% increase of forging efficiency. A good agreement between the experimental and theoretical results was observed.

STRUCTURE DESIGN AND STRENGTH ANALYSIS OF CHILD SEAT FOR MOTORCYCLE

Many people in Indonesia are having a serious safety issue in bringing their children to ride a motorcycle. A proper child seat is needed to guarantee the safety of the child and the rider itself. In this paper, the structural design of a child seat for a motorcycle using a spring-damper system is presented as a reference to build a safe and comfortable seat. Analysis of the static condition, dynamics condition, buckling, and also fatigue is also done calculated and it is resulting in some safety factors. The safety factors are found to be in the range of 1-11. Based on that analysis result, the conclusion that can be highlighted is that the child seat is safe. Due to some concern related to safety, this innovation is recommended to be applied for mass production, furthermore, improvement, and optimization is also possible for this design.

Equivalent Beam Model for Spatial Repetitive Lattice Structures with Hysteretic Nonlinear Joints

This study presented an equivalent modeling method for analysis of the fundamental harmonic response of the spatial repetitive lattice structures with hysteretic nonlinear joints. Firstly, the joint was modelled as a spatial nonlinear spring-damper system with bilinear hysteresis, the equivalent linear stiffness and viscous damping coefficients of the hysteretic joint were derived using the describing function method. Subsequently, high-precision displacement and rotation fields that consider the warping and distortion of the cross section of the lattice structure were presented for the repeating element and the equivalent continuum modeling method based on the principle of energy equivalence was adopted to obtain an 8-DOFs spatial beam element for the repeating element of the lattice structure. Afterwards, the equations of motion of the equivalent beam model for the lattice structure were established in the frequency domain and solved by using the Newton-Raphson method. In the numerical studies, the joints with axial nonlinearity and rotational nonlinearity were considered, and the influences of joint parameters and excitation amplitude on the dynamic response of the lattice structure were investigated. The correctness of the presented modeling method was verified by comparison with the nonlinear finite element model of the original structure.

Study of needle seeding machine vibration system

Make analysis of the vibration system in the needle tray seeder and make plate’s vibration simplified as a single degree of freedom spring damping system under harmonic excitation forced vibration. Get the amplitude frequency characteristics of plate vibration. Make analysis of seed vibrating in the air, get the condition that seeds to be absorbed.

Asymmetry in Three-Dimensional Sprinting with and without Running-Specific Prostheses

As a whole, human sprinting seems to be a completely periodic and symmetrical motion. This view is changed when a person runs with a running-specific prosthesis after a unilateral amputation. The aim of our study is to investigate differences and similarities between unilateral below-knee amputee and non-amputee sprinters—especially with regard to whether asymmetry is a distracting factor for sprint performance. We established three-dimensional rigid multibody models of one unilateral transtibial amputee athlete and for reference purposes of three non-amputee athletes. They consist of 16 bodies (head, ipper, middle and lower trunk, upper and lower arms, hands, thighs, shanks and feet/running specific prosthesis) with 30 or 31 degrees of freedom (DOFs) for the amputee and the non-amputee athletes, respectively. Six DOFs are associated with the floating base, the remaining ones are rotational DOFs. The internal joints are equipped with torque actuators except for the prosthetic ankle joint. To model the spring-like properties of the prosthesis, the actuator is replaced by a linear spring-damper system. We consider a pair of steps which is modeled as a multiphase problem with each step consisting of a flight, touchdown and single-leg contact phase. Each phase is described by its own set of differential equations. By combining motion capture recordings with a least squares optimal control problem formulation including constraints, we reconstructed the dynamics of one sprinting trial for each athlete. The results show that even the non-amputee athletes showed less symmetrical sprinting than expected when examined on an individual level. Nevertheless, the asymmetry is much more pronounced in the amputee athlete. The amputee athlete applies larger torques in the arm and trunk joints to compensate the asymmetry and experiences a destabilizing influence of the trunk movement. Hence, the inter-limb asymmetry of the amputee has a significant effect on the control of the sprint movement and the maintenance of an upright body position.

Structural controllability of networked relative coupling systems

This paper studies the controllability of networked relative coupling systems (NRCSs), in which subsystems are of fixed high-order linear dynamics and coupled through relative variables depending on their neighbors, from a structural perspective. The purpose is to explore conditions for subsystem dynamics and network topologies under which for almost all weights of the subsystem interaction links, the corresponding numerical NRCSs are controllable, which is called structurally controllable. Three types of subsystem interaction fashions are considered: (1) each subsystem is single-input–single-output (SISO), (2) each subsystem is multiple-input–multiple-output (MIMO), and the weights for all channels between two subsystems are identical, and (3) each subsystem is MIMO, but different channels between two subsystems can be weighted differently. We show that all parameter-dependent modes of the NRCSs are generically controllable under some necessary connectivity conditions. We then derive necessary and/or sufficient conditions for structural controllability depending on subsystem dynamics and network topologies’ connectivity in a decoupled form for all the three interaction fashions. We also extend our results to handle certain subsystem heterogeneities and demonstrate their direct applications on some practical systems, including the mass–spring–damper system and the power network.

Fox H-functions as exact solutions for Caputo type mass spring damper system under Sumudu transform

Fox H-functions as exact solutions for Caputo type mass spring damper system under Sumudu transform

Design & Analysis of Dynamic Response in Hydrolic Equipment Working with Heavy Loads

Hydraulic system has benefits over pneumatic or electric systems, especially when heavy loads are involved, or when very smooth and precise position or pressure control is required. Hydraulic actuators have several advantages including the fact that they produce less heat and electrical interference at the machine than do electric actuators. A simulation model of the support was established to determine the dynamic responses of the hydraulic support under dual impacts from its roof and shield beams, and the column and balance jack were replaced using a spring-damper system. Analysis of poses was performed and dynamic support responses were obtained.

Contact Stress Distribution of a Pear Cam Profile with Roller Follower Mechanism

The problem of this paper is the high contact stress at the point of contact between the cam and the follower. A pear cam and roller follower mechanism were studied and analyzed for different position of the follower and different contact compression load. The objective of this paper is to study the effect of contact compression load on the contact stress distribution of the cam profile at the point of contact. Four different positions of the follower with the cam was considered (0°, 90°, 180°, and 270°). The theory of circular plate was applied to derive the analytic solution of the contact stress. The numerical simulation had been done using ANSYS Ver. 19.2 package to determine the contact stress, while SolidWorks software was used to investigate follower displacement, velocity, and acceleration. Four distinct values of the compression contact load, such as 3.121 N, 6.242 N, 9.364 N, and 12.485 N, were used in the numerical simulation. In the experiment setup, a photo-elastic technique was carried out in the field of polarized light to exhibit the stress distribution on the cam specimen. The annealed PSM-4 backalate material was used in the experiment setup. The experimental value of contact stress was checked and verified analytically and numerically at the point of contact. The innovation in this paper the use of spring-damper system which reduce the value of contact stress at the point of contact. The contact stress was maximum 2.136 MPa when the follower located at 270° with the cam, while the contact stress was minimum 1.802 MPa when the follower located at 180° at compression load 12.485 N.

Surface Prediction for Spatial Augmented Reality Applications

In spatial augmented reality applications, incorrect projection mapping may occur when projecting images onto moving non-rigid surfaces. This may detract from the user experience, as the image may not be perceived as originally intended. This is especially apparent when using low-cost projectors and cameras or when surfaces are moving quickly. In this paper, an algorithm is developed which predicts the motion of a non-rigid surface, so that when an image is being projected onto the surface, the projection “matches” the surface shape, while using low-cost equipment. Using an interconnected mass–spring–damper system to model the surface, the surface position is predicted using a Kalman filter-based algorithm, which also compensates for the processing delays and fast-moving surfaces. To accurately model real-world materials, the mass–spring system parameters are found using a system identification approach. When the prediction algorithm is implemented experimentally, in real-time, the results show convergent results in the sense that the surface predictions converge to the measured position of a non-rigid surface. The error results show that the algorithm is both accurate and robust and can currently be applied in spatial augmented reality applications.

Formula omitted] and [formula omitted] optimal sampled-data controller synthesis: A hybrid systems approach with mixed discrete/continuous specifications

In this paper, a tractable sampled-data controller synthesis method is proposed for linear time-invariant plants that gives guarantees for stability and performance of the closed-loop system in terms of the H∞- and H2-norm. This is done by taking a so-called jump/hybrid systems approach, which allows formulating linear matrix inequalities using an explicit solution to the Riccati differential equation. Furthermore, the sampled-data problem is formulated such that continuous-time design techniques like H∞ loop-shaping can be used in a sampled-data context. To do so, it is essential to consider mixed discrete/continuous specifications, in which both discrete and continuous signals are weighted using weighting filters. This leads to a generalised plant that has both continuous-time and discrete-time dynamics. The controller design method is demonstrated on a benchmark example, in which we compare to existing results in the literature, and on a design example of reference tracking of a two-mass–spring–damper system.

Modeling the Quarter-Vehicle: Use of Passive Sensor Data for Road Condition Monitoring

In recent years, automated driving has become one of the most important research fields in the automotive industry. A key component for a successful substitution of human driving by vehicles is a real-time model of the current environment including the traffic situation, the guide-way, and the road itself. We propose a solution for measuring road conditions within the spring-damper system of the vehicle. In this paper, we utilize a Vehicle Level Sensor (VLS) and an Acceleration Sensor (AS), both of which are standard components in modern vehicles, for road condition monitoring. Our model-based approach therefore consists purely of additional software. We present a calculation of the Quarter Vehicle Model (QVM) for road elevation measurements to enable each connected vehicle to provide valid data for a potential crowd-sensing approach, where every vehicle contributes past data and consumes data for upcoming segments. The generated data are capable of providing the environment model with real-time data. Our calculations are first validated in a laboratory setup, representing a down-scaled Quarter-Vehicle. The knowledge gained it then applied to a real vehicle. For this purpose, the measurement setup is explained, the model-based calculation and the parameters are adjusted, and the results are compared.

A Position-Control Based Approach to Haptic Rendering of Stiff Objects.

Conventional force rendering methods in haptic applications often suffer stability issues when simulating interactions with stiff objects such as a virtual wall. This paper argues that the emphasis in such scenarios is to minimize the penetration into the virtual wall instead of modeling the wall as a spring-damper system. Therefore, we propose an approach using a position controller to achieve better haptic rendering of the virtual wall. The proposed approach exploits model-based development tools to obtain the linear control system model without the need for an analytical model of the dynamics of the haptic device. A simulation-based performance comparison of two different controllers has been made for a 6-DOF parallel structure haptic device.