Terrain compliance is a critical parameter for the performance of legged locomotion. In this work, a single actuator monopod robot hopping on rough compliant terrain is considered. Based on our controller for flat compliant terrains, this paper introduces the necessary modifications, which allow the robot to tackle the disturbance of small inclinations. Using the developed method, the robot is examined on its performance to traverse rough terrains, while maintaining the goals of reaching a desired height and forward velocity. As the increased compliance and inclination alter the energy requirements from the controller actuator, the Cost of Transport (CoT) index for a number of scenarios is studied. The correlation between terrain parameters and the CoT is presented, and useful conclusions, which can aid the understanding of the behavior of legged robots in realistic terrains are extracted.

Legged locomotion is a rapidly advancing area in robotics, yet still a large number of open questions exist. This work focuses on the foot-terrain interaction and its effect on the motion of a one-legged system. This interaction is usually tackled by disregarding some of the effects of ground deformation like permanent deformation and compaction. Inspired by other areas of engineering, an impact dynamics model is developed, allowing a more thorough study of the behavior during fast dynamic walking. This approach can be regarded as a viscoplastic one. The monopod controller presented in previous work is extended to cope with deformable terrains, based on energy dissipation considerations, without requiring the knowledge of the ground parameters. Simulation results prove the validity of the theory presented.

One of the most demanding tasks for a robotic servicer is capturing a target. During this task, the mechanical systems can be subject to large forces for short duration (impacts). In space servicers, these impacts may render the capturing of a target impossible without the use of undesirable fuel-consuming maneuvers. This paper presents an approach for minimizing impact reactions, using the Center of Percussion (CoP), a characteristic of rigid bodies rotating around an axis. This work generalizes and delineates the exact requirements for its use. Application of CoP in multibody systems is demonstrated using the Newton-Euler Algorithm. Implementation guidelines are discussed. Simulations of a planar space robot system, and a three-dimensional PUMA-like manipulator on a satellite base confirm the benefit of using the CoP during tasks that include impacts.