Introduction Four-bar linkage knee mechanisms for the trans-femoral amputee are widely available, but although they may offer functional advantages to certain amputees, they are fitted in a limited number of cases. It may be assumed that one reason for this is that persons responsible for prescription and fitting may not be familiar with the kinematic characteristics and possible advantages of ...

The optimal design of human lower limb prostheses, in particular of knee devices, is fundamental in order to restore the lost functionality and aesthetic aspect of the amputee’s locomotion. Among all knee devices, the four-bar linkage is still the most widespread mechanism, since, despite its simplicity, it allows the prosthesis to be sufficiently stable and, at the same time, to replicate the ...

At present, multi-bar linkage mechanism is one of the most important directions of mechanical presses’ development. Utilizing the typical multi-linkage drawing mechanism of the plunger slide and compounding its parameters scientifically are a fairly effective way to realize the drawing technology demand. This paper established kinematics mode of the six-bar drawing mechanism by bar-group method...

Four-bar linkage mechanisms are of interest for many specialists in the academia and industry. However, it is one of the mechanisms that is highly nonlinear and exhibits complex behavior. Therefore, it is difficult to model and control their dynamic responses. In this paper, various control schemes are explored and tested on the four-bar mechanism to investigate the dynamical performance under ...

A spherical parallel manipulator (also called an orientational parallel manipulator or rotational parallel manipulator) refers to a threedegree-of-freedom (3-DoF) parallel manipulator in which the moving platform undergoes a 3-DoF spherical motion or rotates about a fixed point. In this paper, we propose a new method for the type synthesis of non-overconstrained (isostatic) spherical parallel m...

 In practice, clearances in the joints are inevitable due to tolerances, and defects arising from design and manufacturing. In the presence of clearance at a joint, a mechanism gains some additional, uncontrollable degrees of freedom which are the source of error. Moreover, joints undergo wear and backlashes and so cannot be used in precision mechanisms. In this study, the dynamic behaviour of ...