DESIGN, ANALYSIS AND DEVELOPMENT OF A QUADRUPED ROBOT

Abstract

Mobile robotics comprises a wide variety of locomotion, from drones to wheeled robots and even multi-legged robots that mimic the nature around us. There have been vast amounts of research and development in the drones and wheeled robot domains. However, the relatively unexplored field of legged locomotion has greater such potential. Legged robots represent a class of ground robots that make use of articulated linkages and specific control systems to move about. Compared to wheeled robots, legged robots can exploit discontinuous pathways and isolated footholds with great efficiency, thereby increasing their reach ability. Legged locomotion is fundamentally periodic in nature with well-defined flight and stance phases in each gait cycle; this cyclic nature is exploited to increase energy efficiency in all legged creatures. These gaits can be utilized differently with respect to the terrain that is explored. In this report, a quadruped robot based on the gait of quadruped mammals is presented by utilizing an elastically loaded scissors mechanism. This allows for a relatively smaller diameter pulley to be used, as instead of pulling on the distal joint, a proximal joint is now created, by the addition of a link, that can be used to retract the entire leg with a smaller angular displacement of the pulley. The smaller input angles required provide a greater mechanical advantage relative to the SLP mechanism. The ability of the leg to be retracted through the proximal joint faster allows for a greater stepping frequency, which in turn increases the speed of the quadruped. A robust mechanical assembly is designed and structurally improved for reduced mass and inertia. The system is tested with several motor placements in the design phase and their performance has been evaluated and their merits and demerits are gauged. The actuators are chosen based on torque calculations. After several iterations, the mechanical design is finalized. Further experiments may be conducted to further study the legged mechanism for different gaits on a planar test bed for planar walking and running motion in addition to the effects of the underlying dynamics dictated by leg for static and dynamic stability. In addition, different gaits will be applied using control system.