Fatigue life investigation for cams with translating roller-follower and translating flat-face follower systems

Int Journal of Mech Sys Dyn

2022

The aim of this article is to detect the detachment between the cam and the follower using the largest Lyapunov exponent parameter, the power density function of fast Fourier transform, and Poinaré maps due to the nonlinear dynamics phenomenon of the follower. The detachment between the cam and the follower was investigated for different cam speeds and different internal distances of the follower guide from inside.This study focuses on the use of the cam-follower system with a bionic quadruped robot through a linkage mechanism. Multishock absorber (spring-damper-mass) systems at the very end of the follower were used to improve the dynamic performance and to reduce the detachment between the cam and the follower. The SolidWorks program was used in the numerical solution, while a high-speed camera at the foreground of the OPTOTRAK 30/20 equipment was used to identify the follower position. The friction and impact were considered between the cam and the follower and between the follower and its guide. In general, when the cam and the follower are in permanent contact, there is no loss in potential energy, and no impact or restitution.The detachment between the cam and the follower increases with increasing coefficient of restitution in the presence of the impact.

“…This is the difference between a multi‐DOF system and a single‐DOF system. The contact force between the cam and the follower is defined in the following equation 19 :

{P}_{{C}}=\frac{1}{\cos ({{\rm{\unicode{x000D8}}}}_{1})}[K{\times }({\rm{\Delta }}+X(t))-m\times \ddot{X}],

where

{P}_{{C}}

is the contact force between the cam and the follower; K is the stiffness of the spring between the follower stem and the installation table;

{\rm{\Delta }}

is the preload spring extension; and m is the mass of the follower stem. Further, 20

\tan ({{\rm{\unicode{x000D8}}}}_{1})=\frac{\dot{X}(t)}{X(t)+{R}_{b}^{2}},

where

{{\rm{\unicode{x000D8}}}}_{1}

is the pressure angle,

{R}_{{b}}

is the radius of the base circle of the cam, and

X(t)

is the product of the follower linear displacement.…”

Section: Equations Of Motion Of a Three‐degree‐of‐freedom Systemmentioning

confidence: 99%

“…This is the difference between a multi-DOF system and a single-DOF system. The contact force between the cam and the follower is defined in the following equation 19 :…”

Section: Equations Of Motion Of a Three-degree-of-freedom Systemmentioning

confidence: 99%

Nonlinear dynamics investigation of contact force in a cam–follower system using the Lyapunov exponent parameter, power spectrum analysis, and Poincaré maps

Int Journal of Mech Sys Dyn

2022

“…Below is the list of impact and contact parameters in which it is used in SolidWorks software. The normal force between the cam and the follower is 18 where:…”

Section: Mathematical Model Validation Of the Follower Movementmentioning

confidence: 99%

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

Proceedings of the Institution of Mechanical Engineers, Part C:

2021

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.

“…The impedance matrix can be put into terms of frequency response matrix, [18]. The contact force expression in terms of the pressure angle has been taken from, [19,20]. The equations of motion with the solution can be seen in Appendix A.…”

Section: Equations Of Motion Of Three Degrees Of Freedom Systemmentioning

confidence: 99%

Detachment Detection in Cam Follower System Due to Nonlinear Dynamics Phenomenon

2021

Machines

The detachment between the cam and the follower was investigated for different cam speeds (N) and different internal distance of the follower guide from inside (I.D.). The detachment between the cam and the follower were detected using largest Lyapunov exponent parameter, power density function of Fast Fourier Transform (FFT), and Poincare’ maps due to the nonlinear dynamics phenomenon of the follower. The follower displacement and the contact force between the cam and the follower were used in the detection of the detachment heights. Multi-degrees of freedom (spring-damper-mass) systems at the very end of the follower were used to improve the dynamic performance and to reduce the detachment between the cam and the follower. Nonlinear response of the follower displacement was calculated at different cam speeds, different coefficient of restitution, different contact conditions, and different internal distance of the follower guide from inside. SolidWorks program was used in the numerical solution while high speed camera at the foreground of the OPTOTRAK 30/20 equipment was used to catch the follower position. The friction and impact were considered between the cam and the follower and between the follower and its guide. The peak of nonlinear response of the follower displacement was reduced to (15%, 32%, 45%, and 62%) after using multiple degrees of freedom systems.