Femoral non-unions are difficult to treat even for the experienced orthopaedic trauma surgeon. If the non-union follows failure of modern stable internal fixation, the complexity of the management is further increased. We report two cases of stiff hypertrophic femoral non-unions after failed locking plate fixation that were successfully treated with a new hexapod circular external fixator. In a...

We have designed an architecture that allows a gait planner to effectively control primitive walking behaviors. The behaviors ensure safe and efficient walking, even without planning; the addition of planning improves performance in rough terrain by allowing the robot to anticipate changes in its gait. We have implemented our approach and demonstrated it on a real robot, Dante II, and on a simu...

Physiological studies suggest that the integration of neural circuits and biomechanics (e.g., muscles) is a key for animals to achieve robust and efficient locomotion over challenging surfaces. Inspired by these studies, we present a neuromechanical controller of a hexapod robot for walking on soft elastic and loose surfaces. It consists of a modular neural network (MNN) and virtual agonist-ant...

Purpose Reducing energy consumption in walking robots is an issue of great importance in field applications such as humanitarian demining so as to increase mission time for a given power supply. The purpose of this paper is to address the problem of improving energy efficiency in statically stable walking machines by comparing two leg, insect and mammal, configurations on the hexapod robotic pl...

Gait generation for hexapod robots can be accomplished with a two-phase process, whereby leg cycles that effectively provide thrust are learned and then the proper selection and coordination of these cycles needed to produce a gait are learned. Genetic algorithms can be used to learn both the leg cycles and the coordination. In previous work, this technique was used successfully to generate gai...

We present the first controller that allows our small hexapod robot, RHex, to descend a wide variety of regular sized, “real-world” stairs. After selecting one of two sets of trajectories, depending on the slope of the stairs, our open-loop, clock-driven controllers require no further operator input nor task level feedback. Energetics for stair descent is captured via specific resistance values...

This report describes the kinematic and dynamic modeling of a hexapod robot. The 6-DOF (degrees of freedom) analytical kinematic and dynamic equations of motion are derived following the classical Newtonian mechanics. Under certain task-specific assumption, it is shown that the complex 6-DOF model can be simplified, resulting in an abstract model. Specifically, the motion of the robot on the ho...

The main goal of the proposed research is to develop a team of micro-machines for in-situ repair and maintenance within constrained and hazardous environments. The use of micro-machines removes human workers from having to crawl within highly cluttered and constrained spaces, breathing in stale air mixed with fumes from welding or particulates from repair work, and provides higher reliability a...

This paper presents the design and implementation of a parallel-kinematic hexapod tool driven by pneumatic actuators. It consists of six discrete linear actuators, each of which is assembled as an antagonistic setup of McKibben pneumatic muscles with pressure and position sensors. Thanks to the antagonistic principle of the units together with the inherently nonlinear behaviour of Mc-Kibben act...