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Creative Design of an Elliptical Trainer with Two Degrees of Freedom

The elliptical trainer is a widely used piece of equipment for fitness and rehabilitation. An elliptical trainer with seven links and eight joints, and two degrees of freedom, can have its range of motion adjusted to match the user's stature, and the user can obtain different athletic effects. It allows for more adjustment than an elliptical trainer with one degree of freedom. In this paper, we refer to the present patents that specify the design requirements and constraints for an elliptical trainer. We then use Yan's creative mechanism design methods, which include generalized principles, number synthesis, specialization, and particularization, to obtain a practicable structure for an elliptical trainer with two degrees of freedom. We obtained five alternative kinds of mechanism. We chose one of them for a simulated kinematic analysis, and manufactured the prototype. This paper can serve not only as a reference for the development of fitness equipment but also as a teaching tool for creative mechanism design courses.