In this work, we present an approach to planning for humanoid mobility. Humanoid mobility is a challenging problem, as the configuration space for a humanoid robot is intractably large, especially if the robot is capable of performing many types of locomotion. For example, a humanoid robot may be able to perform such tasks as bipedal walking, crawling, and climbing. Our approach is to plan for all these tasks within a single search process. This allows the search to reason about all the capabilities of the robot at any point, and to derive the complete solution such that the plan is guaranteed to be feasible.A key observation is that we often can roughly decompose a mobility task into a sequence of smaller tasks, and focus planning efforts to reason over much smaller search spaces. To this end, we leverage the results of a recently developed framework for planning with adaptive dimensionality, and incorporate the capabilities of available controllers directly into the planning process. The resulting planner can also be run in an interleaved fashion alongside execution so that time spent idle is much reduced.

Fluid invasion during cement hydration is governed by, among other factors, differential pressure between the formation fluids and the annular fluid. The primary phenomena influencing pressure in the annulus are evolution of cement slurry physical and chemical properties with time, filtrate lost to the formation, and changes in cement slurry volume during hydration. A successful procedure to design slurries to mitigate fluid invasion shall model these phenomena and provide viable methods to measure model parameters. At the same time, it should be feasible to formulate cement slurries to obtain the parameters necessary for a successful design. This paper discusses model details with emphasis on parameters, their test procedures, and equipment details. Dynamic filter-cake properties are calculated by applying compressible filtration theory on data from a modified fluid loss test. Shrinkage/expansion is measured under temperature using the API ring mold apparatus. Pressure and displacement response to filtrate loss and shrinkage/expansion is dependent on bulk modulus, shear modulus, and static gel strength (SGS) evolution of the cement slurry during hydration. Properties are measured as a function of time using sonic analysis and a rotational gel strength device. Both material properties and volume changes attributed to fluid loss and hydration showed time dependency. Furthermore, the pressure response of two realistic wells having different permeability and pore pressure profiles is analyzed. The two analyzed wells had different pressure responses, indicating that the slurry design should be customized for each well. This difference is attributed to varying capabilities of the well to compensate for volume loss by movement of cement placed adjacent to the permeable section, showing that the relative locations of the filtrate loss and potential fluid influx zones are important. Such an observation is possible only because of the ability to measure and model dynamic properties and events. The proposed methods are practical and can be realized using existing equipment with few procedural changes. Analysis based on these measurements guides the customization of slurry designs.

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