RoLoMa: Robust Loco-Manipulation for Quadruped Robots with Arms

Abstract

Deployment of robotic systems in the real world requires a certain level of robustness in order to deal with uncertainty factors, such as mismatches in the dynamics model, noise in sensor readings, and communication delays. Some approaches tackle these issues reactively at the control stage. However, regardless of the controller, online motion execution can only be as robust as the system capabilities allow at any given state. This is why it is important to have good motion plans to begin with, where robustness is considered proactively. To this end, we propose a metric (derived from first principles) for representing robustness against external disturbances. We then use this metric within our trajectory optimization framework for solving complex loco-manipulation tasks. Through our experiments, we show that trajectories generated using our approach can resist a greater range of forces originating from any possible direction. By using our method, we can compute trajectories that solve tasks as effectively as before, with the added benefit of being able to counteract stronger disturbances in worst-case scenarios.

Legged robots for object manipulation: A review

“…Therefore, a specialized arm can be used to tackle complex real-world tasks such as rotating a handwheel, handling articulated objects, and unlatching a door. (Sleiman et al, 2021;Ferrolho et al, 2022;Mittal et al, 2022), which would be much harder to approach using locomotive legs. In addition, an onboard arm can reach the legs themselves, which may prove useful if the legs need to be repaired or untangled.…”

“…However, non-grasping (non-prehensile) manipulation is another way of moving objects without the requiring a secure grasp, by instead applying forces to push, impacts to kick, or relying on another (nongrasping) type of attachment mechanism to the object such as hooks/ trays (Ruggiero et al, 2018). Performing manipulation tasks with a legged platform also increases the potential vibrations transmitted to the manipulator, which may need to be corrected/accounted for to maintain continuous and secure contact with the object (Ferrolho et al, 2022).…”

A Mixed-Reality Tele-Operation Method for High-Level Control of a Legged-Manipulator Robot

“…Some of the most recent developments in this field are RoLoMa and ALMA, which use as development base the ANYmal quadruped robot, equipped with a ( ) robot (6 DoF) manipulator. Different analyses have been developed, such as dynamic and stability and stability and application tasks as door opening [ 20 , 21 ]. Other studies focuses on the study of generated forces in pick and place task [ 22 ].…”

Versatile multicontact planning and control for legged loco-manipulation

“…Last, to ensure a robust deployment of complex behaviors on such robotic systems, a common approach has been to decompose the problem into an offline planning phase that handles the heavy computations and a reactive control module that tracks the generated plans at high-update rates (76,77). However, when dealing with long-horizon dynamic maneuvers involving multiple discontinuous switches, the accumulated effects of unmodeled disturbances might render the plan unstabilizable with a purely reactive controller.…”