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Prototyping of automated systems
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
A four-bar linkage comprises four bar-shaped links and four turning pairs as shown in Figure 8.62. The link opposite the frame is called the coupler link, and the links which are hinged to the frame are called side-links. A link free to rotate through 3,608 with respect to a second link will be said to revolve relative to the second link. Some important concepts in link mechanisms are as follows: Crank: A side-link that revolves relative to the frame is called a crank.Rocker: Any link that does not revolve is called a rocker.Crank–rocker mechanism: In a four-bar linkage, if the shorter side-link revolves and the other one rocks (i.e., oscillates), it is called a crank–rocker mechanism.Double-crank mechanism: In a four-bar linkage, if both of the side-links revolve, it is called a double-crank mechanism.Double-rocker mechanism: In a four-bar linkage, if both of the side-links rock, it is called a double-rocker mechanism.
Motion and Force Transmission in Linkages
Published in Preben W. Jensen, Classical and Modern Mechanisms for Engineers and Inventors, 2018
A common function of a four-bar linkage is to transform rotary into oscillating motion. Frequently in such applications a large force must be transmitted, or force must be converted at high speed. It is then that the transmission angle becomes of paramount importance.
Path synthesis of a four-bar linkage using a teaching-learning-based optimization algorithm
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2023
Gajanan G. Waghmare, R. V. Rao, Prafulla C. Kulkarni
Four-bar linkage is a combination of four kinematic pairs such that the relative motion between the links or elements is completely constrained. Since the last few decades, efforts were made for path synthesis of a four-bar linkage using a variety of methods including analytical [1, 2], continuation [3], nonlinear goal programming [4, 5], exact gradient [6], coupler-angle function curve [7] and curve curvature methods [8]. It is observed from the literature that for more than five target points there is no analytical solution to the problem of four-bar linkage synthesis. Hence there is a need of advanced optimization methods to solve such type of problems. Few researchers had carried out research work to study the effects of various input parameters on the path synthesis of a four-bar linkage and also tried to achieve effective parameter setting. Kunjur and Krishnamurthy [9] used GA for mechanism dimensional synthesis. Cabrera et al. [10] applied genetic algorithm (GA) for the path synthesis of a four-bar linkage. The objective function had two parts. The first part was concerned with the position error and in the second part the constraints were inserted by the penalty function.
An infinite-order integral disturbance observer for improved estimation of periodic disturbances in motion control systems
Published in Journal of the Chinese Institute of Engineers, 2023
The four-bar linkage is a very popular mechanism that is widely used in automobiles and industrial machines (Khan et al. 2020; Tutunji et al. 2015). Consider a four-bar linkage system, shown in Figure 3. This mechanism is actuated by a permanent-magnet brushless motor, whose rotor shaft is rigidly connected to link 2. There are revolute joints between all adjacent links, and link 1 denotes the ground link that contains the motor’s stator. The dynamics of this system are extremely nonlinear (Khan et al. 2020; Tutunji et al. 2015). In this paper, this system is simply modeled as a double integrator: