This work presents the computational design and validation of the Multi-Arm Relocatable Manipulator (MARM), a three-limb robot for space applications, with particular reference to the MIRROR (i.e., the Multi-arm Installation Robot for Readying ORUs and Reflectors) use-case scenario as proposed by the European Space Agency. A holistic computational design and validation pipeline is proposed, with the aim of comparing different limb designs, as well as ensuring that valid limb candidates enable MARM to perform the complex loco-manipulation tasks required. Moti-vated by the task complexity in terms of kinematic reachability, (self)-collision avoidance, contact wrench limits, and motor torque limits affecting Earth experiments, this work leverages on multiple state-of-art planning and control approaches to aid the robot design and validation. These include sampling-based planning on manifolds, non-linear trajectory optimization, and quadratic programs for inverse dynamics computations with constraints. Finally, we present the attained MARM design and conduct preliminary tests for hardware validation through a set of lab experiments.

This paper presents a framework providing a full pipeline to execute a complex physical interaction behaviour of a humanoid bipedal robot, both from a theoretical and a practical standpoint. Building from a multi-contact control architecture that combines contact planning and reactive force distribution capabilities, the main contribution of this work consists in the integration of a sample-based motion planning layer conceived for transitioning movements where obstacle and self-collisions avoidance is involved. To plan these motions we use Rapidly Exploring Random Tree (RRT) projected on the contacts manifold and validated through the Centroidal Statics (CS) model, to ensure static balance on non-coplanar surfaces. Finally, we successfully validate the presented planning and control architecture on the humanoid robot COMAN+ performing a wall-plank task.

In this paper we propose a novel hybrid walking pattern generator which combines results from the virtual constraints and the preview control theories for bipedal locomotion. This choice is motivated by findings in biomechanics that show how the dynamic motion of the human walk is mainly generated by the sagittal component of the stepping. Thus, we choose the conservative preview control to generate the lateral motion while we pick a more dynamical framework such as the virtual constraints for the sagittal motion. We investigate how the time-dependent preview control and the time-independent virtual constraints approach can be integrated together in a humanoid locomotion and finally we show promising results on COMAN+, the new humanoid robot from Istituto Italiano di Tecnologia.

Inspired by the ability of animals to rely on proprioception and vestibular feedback to adapt their gait, we propose a modular framework for autonomous locomotion that relies on force sensing and inertial information. A first controller exploits anti-compliance, a new application of positive force feedback, to quickly react against obstacles upon impact. We hypothesize that, in situations where a robot experiences occasional impacts with the environment, anti-compliance can help negotiate unknown obstacles, similar to biological systems where positive feedback enables fast responses to external stimuli. A novel parallel controller, based on a bi-stable dynamical system, continuously adjusts the robot's direction of locomotion, and reverts it in reaction to major swerves. We present experimental results, demonstrating how our framework allows a snake robot to autonomously locomote through a row of unevenly-spaced obstacles. Finally, we extend our proprioceptive controller to legged locomotion, showing how a hexaprint robot can adapt its motion to climb over obstacles.

This paper proposes the implementation of an impedance controller on the ankle level of COMAN+, a robot with parallel kinematics ankles actuated by a dual four-bar mechanism. The main contribution of the work is a realization of said control scheme that grants a less abrupt and safer robot response in case of system failures, that would cause the local joint torque controllers to lose their torque reference inputs. In particular, we propose a semi-centralized impedance control implementation which eliminates the instability of the pure joint torque control schemes used in the classical fully centralized methods when torque reference interruptions occur. Finally, we present experimental results, proving the effectiveness of our method and demonstrating how it ensures a safer behaviour compared to a fully centralized impedance control implementation when the communication to the ankle joints is interrupted. This paper is a follow-up work of [1], which presented and analyzed the parallel kinematics ankles.