Using simple running models, researchers have argued that swing-leg retraction can improve running robot performance. In this paper, we investigate whether this holds for a more realistic simulation model validated against a physical running robot. We find that swing-leg retraction can improve stability and disturbance rejection. Alternatively, swing-leg retraction can simultaneously reduce tou...

This paper presents a pronking controller for our six-legged robot RHex. Development of the controller begins with a passive-dynamics approach, ensuring that the robot is naturally suited to running. Running with flight phase is then achieved using only proprioceptive (joint angle sensing only) feedback for touchdown detection and for tracking fixed joint reference trajectories. Body pitch osci...

The fields of control and robotics are contributing to the development of bipedal robots that can realize walking motions with the stability and agility of a human being. Dynamic models for bipeds are hybrid in nature. They contain both continuous and discrete elements, with switching events that are spatially driven by unilateral constraints at ground contact and impulse-like forces that occur...

Abstract Carrying out an approach that is as economical and safe possible remains a challenge for flight crews, with multitude of requirements to meet simultaneously. For aircraft descend from cruise altitude touchdown the lowest fuel consumption noise signature, required both at idle thrust in ideal speed follows vertical profile without using brakes, extending landing gear too early, or flyin...

The evolution of the combined solid–fluid motion when a solid body undergoes a skimming impact with (and rebounds from) a shallow liquid layer is investigated. A model is derived coupling the motion of the body to the fluid dynamics of the liquid layer. This predicts that the lift on the body induced by the pressure in the liquid layer is sufficient to entirely retard its incident downward moti...

Human feet and toes provide a mechanism for changing the gear ratio of the ankle extensor muscles during a running step. A variable gear ratio could enhance muscle performance during constant-speed running by applying a more effective prestretch during landing, while maintaining the muscles near the high-efficiency or high-power portion of the force-velocity curve during takeoff. Furthermore, d...

We introduce a low-dimensional kinematic abstraction—i.e., template—for miniature legged robots that can be used for quasi-static motion planning in the horizontal plane. The template comprises a rigid torso and four rigid legs which engage in an alternating tetrapod gait. As the gait is executed, the torso and the legs form two switching four-bar linkages, parameterized by the leg touchdown an...

The identification of herbicide families that act through the inhibition of amino acid biosynthesis has resulted in revolutionary progress in agricultural practices. This review describes three herbicide classes which act through this mode-of-action; including glufosinate (also called phosphinothricin, Liberty, Ignite, or Finale) which inhibits ammonia assimilation, glyphosate (Roundup, Tou...

Minimalist running footwear has grown increasingly popular. Prior studies that have compared lower extremity biomechanics in minimalist running to traditional running conditions are largely limited to a single running velocity. This study compares the effects of running at various speeds on foot strike pattern, stride length, knee angles and ankle angles in traditional, barefoot, and minimalist...