Walking Stabilization Using Step Timing and Location Adjustment on the Humanoid Robot, Atlas

While humans are highly capable of recovering from external disturbances and uncertainties that result in large tracking errors, humanoid robots have yet to reliably mimic this level of robustness. Essential to this is the ability to combine traditional "ankle strategy" balancing with step timing and location adjustment techniques. In doing so, the robot is able to step quickly to the necessary location to continue walking. In this work, we present both a new swing speed up algorithm to adjust the step timing, allowing the robot to set the foot down more quickly to recover from errors in the direction of the current capture point dynamics, and a new algorithm to adjust the desired footstep, expanding the base of support to utilize the center of pressure (CoP)-based ankle strategy for balance. We then utilize the desired centroidal moment pivot (CMP) to calculate the momentum rate of change for our inverse-dynamics based whole-body controller. We present simulation and experimental results using this work, and discuss performance limitations and potential improvements

Straight-Leg Walking Through Underconstrained Whole-Body Control

We present an approach for achieving a natural, efficient gait on bipedal robots using straightened legs and toe-off. Our algorithm avoids complex height planning by allowing a whole-body controller to determine the straightest possible leg configuration at run-time. The controller solutions are biased towards a straight leg configuration by projecting leg joint angle objectives into the null-space of the other quadratic program motion objectives. To allow the legs to remain straight throughout the gait, toe-off was utilized to increase the kinematic reachability of the legs. The toe-off motion is achieved through underconstraining the foot position, allowing it to emerge naturally. We applied this approach of under-specifying the motion objectives to the Atlas humanoid, allowing it to walk over a variety of terrain. We present both experimental and simulation results and discuss performance limitations and potential improvements.Comment: Submitted to 2018 IEEE International Conference on Robotics and Automatio

ihmcrobotics/ihmc-open-robotics-software: SRC Finals

This release marks the version used in the NASA Space Robotics Challenge Finals

ihmcrobotics/ihmc-open-robotics-software: 0.11 Release Notes

This release features mostly improvements in the planning behaviors. Unit Test Results https://bamboo.ihmc.us/browse/LIBS-IHMCOPENROBOTICSSOFTWAREFAST-400 3,046 tests in total 1 test failed 20 tests were skipped 311 minutes taken in total. Failing test: VisibilityGraphsFrameworkTest.testDatasetsWithoutOcclusion Atlas Hardware Test Log video: https://youtu.be/rq6zIrvAts4 *** NOTE: The user interface referred to is proprietary software. Please contact IHMC for a license. Robot starts correctly and arm, chest, and head move to their default configurations. LIDAR works in the user interface. REA works and planar regions show up in the user interface. Flat ground walking works well consistently without shaking. Turn in place Walk forwards Walk backwards Walk sideways Chest and head motions can be commanded from the user interface. Arm motions can be commanded from the user interface and arm home options in the interface work as expected. Hands not working Pelvis motions can be commanded from the user interfaces and the center of mass height slider works. Foot motions in the air can be commanded from the user interface. ~1.5 Hz oscillation during single support The robot can run through the final tab motions: Running Man, Karate Kid 1, and Karate Kid 2 repeatedly without falling. Falls over when changing too quickly The robot can reach an object on the ground using the whole body IK from the user interface (F9). When the robot executes a step, the footstep reaches the position specified in the user interface without offset. The robot can walk over the sand test bed. The robot can walk over simple cinders using the planar regions module with a rough terrain footstep planner. The robot can walk over slanted conders when operated by a human. Valkyrie Hardware Test The Valkyrie hardware platform is not supported in this release