Certain high speed industrial assembly robots share a peculiar three legged parallel architecture wherein three “hips”, attached to a fixed upper base or “pelvis”, actuate “thighs” connected by “knees” to “shins”. Each shin is a parallelogramic four-bar linkage. “Ankles” are connected to a common end effector “foot” which executes spatial translatory motion. Inverse and direct kinematic analyse...

In this paper we present a new approach for dynamic motion planning for legged robots. We formulate a trajectory optimization problem based on a compact form of the robot dynamics. Such a form is obtained by projecting the rigid body dynamics onto the null space of the Constraint Jacobian. As consequence of the projection, contact forces are removed from the model but their effects are still ta...

This paper studies the motion of a large and highly mobile six-legged lunar vehicle called athlete, developed by the Jet Propulsion Laboratory. This vehicle rolls on wheels when possible, but can use the wheels as feet to walk when necessary. While gaited walking may suffice for most situations, rough and steep terrain requires novel sequences of footsteps and postural adjustments that are spec...

Stabilizing legged robot locomotion on a dynamic rigid surface (DRS) (i.e., that moves in the inertial frame) is complex planning and control problem. The complexity arises due to hybrid nonlinear walking dynamics subject explicitly time-varying holonomic constraints caused by movement. first main contribution of this study extension capture point from static DRS as well use resulting for onlin...

This paper presents an adaptive control scheme for the four legged walking machine BISAM. The task of the adaptive control is to learn sensor based reflexes for posture control. For this purpose, an incremental learning scheme is developed based on reinforcement learning. For the planned trajectory of the CoM the data taken from a goat are chosen as a basis, to investigate the transfer potentia...

We refine and advance a notion of parallel composition to achieve for the first time a stability proof and empirical demonstration of a steady-state gait on a highly coupled 3DOF legged platform controlled by two simple (decoupled) feedback laws that provably stabilize in isolation two simple 1DOF mechanical subsystems. Specifically, we stabilize a limit cycle on a tailed monoped to excite sust...

Eurhytbmy means a state of harmony between body and mind. Reflecting this theme, the animation depicts animals, humans and a flock of birds joining together in a surrealistic spiritual dance in a deserted temple courtyard. Adding a sense of religious mystery to the surroundings, the temple, bearing a resemblance to an Islamic mosque, is decorated with symbols from other religions: Egyptian hier...

In 1709, Berkeley hypothesized of the human that distance is measurable by 'the motion of his body, which is perceivable by touch'. To be sufficiently general and reliable, Berkeley's hypothesis must imply that distance measured by legged locomotion approximates actual distance, with the measure invariant to gait, speed and number of steps. We studied blindfolded human participants in a task in...

As RoboCup continues its march towards the day when robots play soccer against people, the focus of researchers’ efforts is slowly shifting from low-level systems (vision, motion, self-localization, etc) to high-level systems such as strategy and cooperation. In the Four-Legged League (recently renamed to the Standard Platform League), teams are still struggling with this transition. While the ...