Sliding–crawling parallelogram mechanism

•A parallelogram mechanism with sliding and crawling motion is introduced.•A complete kinematic and dynamic analysis of the mechanism is presented.•Experimental results of physical prototypes of the mechanism are presented.

This paper introduces two mobile devices based on variations of a single parallelogram mechanism with one degree of freedom. The mechanisms can execute sliding and crawling motions along the ground. Each design has two opposite links in contact with the ground (called left foot and right foot in this paper) and two other links (called the cranks) that move in the air. With the cranks installed on a horizontal plane, and rotating in the same direction, the mechanism can slide along the ground. With the cranks installed on different heights and rotating in opposite sense relative to each other, the mechanism can slide and crawl along the ground. The former design is referred to as the sliding mechanism, and the latter one as the sliding–crawling mechanism. The sliding–crawling mechanism can switch its locomotion modes between sliding and crawling at its singular position. A detailed kinematic and dynamic analysis is presented for both designs. The results of testing the designs via experiments conducted on physical prototypes are presented.