Residual Vibration Criteria Applied to Multiple Degree of Freedom Cam Followers

1981 ◽  
Vol 103 (4) ◽  
pp. 702-705 ◽  
Author(s):  
J. L. Wiederrich
Keyword(s):  
Modal Analysis ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Degree Of Freedom ◽  
Operating Speed ◽  
Residual Vibration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Cam Follower

The vibration characteristics of a cam motion are generally presented by plotting the single degree of freedom residual vibration as a function of normalized operating speed. In this paper it is shown that by applying the methods of modal analysis, these residual vibration characteristics can be extended to the characterization of the vibration response of a multiple degree of freedom cam follower system.

scholarly journals ALGORITMA SIMULASI NUMERIK GETARAN DIRRECT INLINE HARMONICAL CAM FOLLOWER PADA VALVE TRAIN MANIFOLD MOTOR DIESEL

2021 ◽  
Vol 2 ◽  
pp. 45-51
Author(s):  
Abdul Hadi ◽  
B G Tentua
Keyword(s):  
Random Process ◽  
Degree Of Freedom ◽  
Least Square ◽  
Valve Train ◽  
Single Degree Of Freedom ◽  
Ordinary Least Square ◽  
Single Degree ◽  
Level Data ◽  
Data Record ◽  
Cam Follower

Abstrak Penelitian ini dibuat untuk mengetahui getaran vertical direct inline dari suatu mekanisme ekivalen cam follower dengan profil cam harmonik pada suatu manifold -valve train motor diesel. Masalahnya dimulai dengan penentuan koefisien redaman viscous dan koefisien kekakuan pegas ekivalen sistem yang mana sulit ditentukan secara langsung. Oleh karena secara praktis dapat dipandang bahwa sinyal sistem adalah bersifat deterministick random process maka untuk mengatasi kesulitan ini dilakukan suatu analisa gabungan deduksi dan induksi yaitu dalam model estimasi ordinary least square (OLS) dan simulasi numerik Newton-Rhapson dengan mengacu pada data record hasil pengukuran eksperimental respon getaran yang ditunjukkan oleh sensor accelerometer. Sinyal getaran respon sistem dengan model mekanik single degree of freedom (1-dof) ini kenudian diolah baik dalam domain waktu atau domain frekuensi dengan menerapkanLaplace Transform dan Fast Furrior Transform (FFT). Hasilnya menunjukan bahwa komputasi numerik itu dapat dibuat untuk mengetahui harga-harga koefisien redaman viscous ekivalen,  koefisien kekakuan pegas ekivalen dan initial tensiom clearance ekivalen sedemikian hingga selanjutnya respon dinamik sinyal getaran sistem dapat diestimasi dengan menerapkan metode simulasi numerik Runge-Kutta order ke-empat. Algoritma hasil formulasinya dengan demikian dapat menjadi lebih general untuk menjawab berbagai persoalan amplitude getaran pada level data percepatan eksitasi ekivalen multi input multi output (MIMO) dalam berbagai variasi sistem cam-follower yang diberikan sebagaimana dimaksud. 

Single Degree-of-Freedom Modeling of the Nonlinear Vibration Response of a Machining Robot

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Yaser Mohammadi ◽  
Keivan Ahmadi
Keyword(s):  
Control Strategies ◽  
Vibration Response ◽  
Industrial Robots ◽  
Degree Of Freedom ◽  
Restoring Force ◽  
Single Degree Of Freedom ◽  
Machining Forces ◽  
Sdof System ◽  
Single Degree ◽  
Machining Robot

Abstract Highly dynamic machining forces can cause excessive and unstable vibrations when industrial robots are used to perform high-force operations such as milling and drilling. Implementing appropriate optimization and control strategies to suppress vibrations during robotic machining requires accurate models of the robot’s vibration response to the machining forces generated at its tool center point (TCP). The existing models of machining vibrations assume the linearity of the structural dynamics of the robotic arm. This assumption, considering the inherent nonlinearities in the robot’s revolute joints, may cause considerable inaccuracies in predicting the extent and stability of vibrations during the process. In this article, a single degree-of-freedom (SDOF) system with the nonlinear restoring force is used to model the vibration response of a KUKA machining robot at its TCP (i.e., machining tool-tip). The experimental identification of the restoring force shows that its damping and stiffness components can be approximated using cubic models. Subsequently, the higher-order frequency response functions (HFRFs) of the SDOF system are estimated experimentally, and the parameters of the SDOF system are identified by curve fitting the resulting HFRFs. The accuracy of the presented SDOF modeling approach in capturing the nonlinearity of the TCP vibration response is verified experimentally. It is shown that the identified models accurately predict the variation of the receptance of the nonlinear system in the vicinity of well-separated peaks, but nonlinear coupling around closely spaced peaks may cause inaccuracies in the prediction of system dynamics.

The Characterization of Cam Drive System Windup

1980 ◽  
Vol 102 (2) ◽  
pp. 278-285 ◽  
Author(s):  
L. E. Szakallas ◽  
M. Savage
Keyword(s):  
Nonlinear Vibration ◽  
Dimensional Analysis ◽  
Drive System ◽  
Degree Of Freedom ◽  
Follower Force ◽  
Vibration Level ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
High Speeds

The vibration in a cam driven mechanism due to drive system windup can be a serious problem at high speeds. A single degree of freedom model of this source of vibration shows that it is a self-induced nonlinear vibration. By dimensional analysis, two ratios are established to characterize the level of vibration. Maximum drive system windup and maximum radial follower force ratios are presented in chart form to characterize the vibration level. Systems studied are harmonic and cycloidal rises with open and closed track cam surfaces.

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