A comprehensive survey of the analytical, numerical and experimental methodologies for dynamics of multibody mechanical systems with clearance or imperfect joints

Dynamics analysis of planar rigid-flexible coupling deployable solar array system with multiple revolute clearance joints

Experimental investigation of flexible connection and clearance joint effects on the vibration responses of mechanisms

Virtually all machines and mechanisms use mechanical joints that are not perfect from the kinematic point of view and for which tolerances, in the fitting of their components, are specified. Together with such controlled clearances, mechanical joints may require the use of bushing elements, such as those used in vehicle suspensions. Furthermore, in many situations the joints exhibit limits (stops) in their translational or rotational motion that have to be taken into account when modeling them. The dynamic response of the mechanical systems that use such realistic mechanical joints is largely dependent on their characteristic dimensions and material properties of the compliant elements, implying that correct models of these systems must include realistic models of the bushing/clearance joints and of the joint stops. Several works addressed the modeling of imperfect joints to account for the existence of clearances and bushings, generally independently of the formulation of the perfect kinematic joints. This work proposes a formulation in which both perfect and clearance/bushing joints share the same kinematic information making their modeling data similar and enabling their easy permutation in the context of multibody systems modeling. The proposed methodology is suitable for the most common mechanical joints and easily extended to many other joint types benefiting the exploration of a wide number of modeling applications, including the representation of cut-joints required for some formulations in multibody dynamics. The formulation presented in this work is applied to several demonstrative examples of spatial mechanisms to show the need to consider the type of imperfect joints and/or joints with stops modeling in practical applications.

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A unified formulation for mechanical joints with and without clearances/bushings and/or stops in the framework of multibody systems

Analysis of the joint clearance effects on a compliant spatial mechanism

In the current study, the behavior of a crank–slider mechanism with single and multiple clearance joints is analyzed. For this purpose nonlinear dynamics of the system are discussed, using Poincare maps and bifurcation diagrams. Subsequently, the effects of joint friction on dynamical behavior and nonlinear response of the mechanism are investigated. Afterward, a control scheme providing continuous contact in joints, with the aim of maintaining a more stable behavior, is proposed. The control scheme is easy to apply and, since continuous contact between bodies in joints is established, several undesired effects normally caused because of clearance joints are prevented or reduced. Also the limitation of the proposed control method is investigated.

Modeling and control of crank–slider mechanism with multiple clearance joints

Dynamical behaviors and control of planar crank–slider mechanism considering the effects of joint clearance and link flexibility are studied. A control scheme for maintaining continuous contact is proposed. It was observed that using one actuator for control scheme might cause the actuator to reach its saturation limit, a problem that was bypassed by installing an additional actuator on connecting rod. In one actuator case, only continuous contact can be obtained, while with the aid of two actuators, point contact can be achieved. Great improvements in the performance of mechanism and reduction of vibrations are observed in the case of using an additional actuator.

Nonlinear dynamics and control of crank–slider mechanism with link flexibility and joint clearance:

Control of MIMO mechanical systems interacting with actuators through viscoelastic linkages

FEA based discrete-time sliding mode control of uncertain continuum mechanics MIMO vibrational systems

This paper focuses on proposing a novel method regarding general tracking control of discrete high-order parametrically uncertain systems with unknown arbitrary switching signals and unknowable tim...

Discrete-time sliding-surface based control of parametrically uncertain nonlinear systems with unknown time-delay and inaccessible switching mode detection

Sadeq Yaqubi

Papers

Modeling and control of crank–slider mechanism with multiple clearance joints

Nonlinear dynamics and control of crank–slider mechanism with link flexibility and joint clearance:

Control of MIMO mechanical systems interacting with actuators through viscoelastic linkages

FEA based discrete-time sliding mode control of uncertain continuum mechanics MIMO vibrational systems

Discrete-time sliding-surface based control of parametrically uncertain nonlinear systems with unknown time-delay and inaccessible switching mode detection