Multi-contact Walking Pattern Generation based on Model Preview Control of 3D COM Accelerations

We present a multi-contact walking pattern generator based on preview-control of the 3D acceleration of the center of mass (COM). A key point in the design of our algorithm is the calculation of contact-stability constraints. Thanks to a mathematical observation on the algebraic nature of the frictional wrench cone, we show that the 3D volume of feasible COM accelerations is a always a downward-pointing cone. We reduce its computation to a convex hull of (dual) 2D points, for which optimal O(n log n) algorithms are readily available. This reformulation brings a significant speedup compared to previous methods, which allows us to compute time-varying contact-stability criteria fast enough for the control loop. Next, we propose a conservative trajectory-wide contact-stability criterion, which can be derived from COM-acceleration volumes at marginal cost and directly applied in a model-predictive controller. We finally implement this pipeline and exemplify it with the HRP-4 humanoid model in multi-contact dynamically walking scenarios

Static Balancing of Wheeled-legged Hexapod Robots

Locomotion over different terrain types, whether flat or uneven, is very important for a wide range of service operations in robotics. Potential applications range from surveillance, rescue, or hospital assistance. Wheeled-legged hexapod robots have been designed to solve these locomotion tasks. Given the wide range of feasible operations, one of the key operation planning issues is related to the robot balancing during motion tasks. Usually this problem is related with the pose of the robot’s center of mass, which can be addressed using different mathematical techniques. This paper proposes a new practical technique for balancing wheeled-legged hexapod robots, where a Biodex Balance System model SD (for static & dynamic) is used to obtain the effective position of the center of mass, thus it can be recalculated to its optimal position. Experimental tests are carried out to evaluate the effectiveness of this technique and modify and improve the position of hexapod robots’ center of mass

Experimental Investigation of the Vibro-impact Capsule System

Dr. Yang Liu would like to acknowledge the financial support for the Small Research Grant (31841) by the Carnegie Trust for the Universities of Scotland. This work is also partially supported by the National Natural Science Foundation of China (Grant Nos. 11672257 and 11402224), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20161314).Peer reviewedPublisher PD

Design of a hexapod robotic system

The main purpose of this work was to design a prototype of an autonomous hexapod robot. This paper reports on an initial phase, where the basic geometry of the system was specified and improved through a kinematics and dynamic study, using a motion analysis software. This also allowed the design of all mechanical components and the definition of motion generation needs. In this paper the importance of legged robots on mobile research is emphasised. The capabilities of the computational programs specially dedicated to the analysis of mechanical systems are demonstrated. The mobility of the geometric model presented in this paper is a trade-off between natural idea and technical feasibility. Some results of the virtual simulation of the movement of this hexapod robotic system are presented

Legged Robots

International audienc

Kinematics and dynamics study of a hexapod robotic system using computational packages’ capabilities

The main purpose of this work was to perform kinematics and dynamics analysis of a prototype of an autonomous hexapod robot. This paper reports on an initial phase, where the basic geometry of the system was specified and improved through a kinematics and dynamic study by using a motion analysis software. This study also allowed the design of all mechanical components and the definition of motion generation needs. In this paper the importance of legged robots on mobile research is emphasised. The capabilities of the computational programs specially dedicated to the analysis of mechanical systems are also discussed. The mobility of the geometric model presented in this paper is a trade-off between natural idea and technical feasibility. Some results of the computational simulations of the movement of the proposed hexapod robotic system are presented and discussed under the premises and assumptions adopted in this work

In silico case studies of compliant robots: AMARSI deliverable 3.3

In the deliverable 3.2 we presented how the morphological computing ap- proach can significantly facilitate the control strategy in several scenarios, e.g. quadruped locomotion, bipedal locomotion and reaching. In particular, the Kitty experimental platform is an example of the use of morphological computation to allow quadruped locomotion. In this deliverable we continue with the simulation studies on the application of the different morphological computation strategies to control a robotic system