Miscellaneous

J. Carius, "Dynamic Maneuvers with a Single Wheel Robot", Bachelor Thesis, ETH Zurich, 2014. Supervised by P. Fankhauser, M. Hutter.

This work documents the development of a single wheel rolling robot prototype with a novel way of actuation. Formerly, such robots typically used two or more actuation methods such as mass displacement, reaction wheels or control moment gyroscopes. Contrary to that, we use only a single form of internal mass shifting. We decide to realize the moving masses in the form of pendulum arms that are suspended on either side of the wheel and can rotate around the wheel’s axis. The goal of this project is to demonstrate that both driving and jumping is possible with this simple form of actuation. The main focus is thereby placed on the jumping ability. We successfully show that our design is capable of jumping approximately 10 cm high and driving forward and backward with the proposed form of actuation. This report presents the conceptual elaboration of the system, shows simulation results and the implementation of the actual prototype. To limit the scope of this work, we restrict ourselves to the planar case and mount the prototype inside a test stand to constrain motion to a smaller number of degrees of freedom. The overall concept appears promising for further developments where a fully 3D approach can be taken.

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Current and previous single-legged hopping robots are energetically tethered and lack portability. Here, we present the design and control of an untethered, energetically autonomous single-legged hopping robot. The thrust-producing mechanism of the robot’s leg is an actuated prismatic joint, called a linear elastic actuator in parallel (LEAP). The LEAP mechanism comprises a voice coil actuator in parallel with two compression springs, which gives our robot passive compliance. An actuated gimbal hip joint is realized by two standard servomotors. To control the robot, we adapt Raibert’s hopping controller, and find we can maintain balance roughly in-place for up to approx. 7 seconds (19 hops) while continuously hopping.

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Roboticists have designed all sorts of jumping robots over the years, and many of them have been inspired by biology. But, as diverse as the natural world is, evolution hasn’t cracked every option.

Now a team of researchers has investigated the differences between biological and mechanical jumpers – and have managed to design a device capable of leaping over 30 metres into the air. This is 3 times the current record for a jumping robot, and they did it with a technique unavailable to the biological world - work multiplication.

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Title: RAMIEL: A Parallel-Wire Driven Monopedal Robot for High and Continuous Jumping
Authors: Temma Suzuki, Yasunori Toshimitsu, Yuya Nagamatsu, Kento Kawaharazuka, Akihiro Miki, Yoshimoto Ribayashi, Masahiro Bando, Kunio Kojima, Yohei Kakiuchi, Kei Okada, Masayuki Inaba
Accepted at IROS2022

website - tenrobo18.github.io/ramiel-iros2022

arxiv - http://arxiv.org/abs/2311.04573

Legged robots with high locomotive performance have been extensively studied, and various leg structures have been proposed. Especially, a leg structure that can achieve both continuous and high jumps is advantageous for moving around in a three-dimensional environment. In this study, we propose a parallel wire-driven leg structure, which has one DoF of linear motion and two DoFs of rotation and is controlled by six wires, as a structure that can achieve both continuous jumping and high jumping. The proposed structure can simultaneously achieve high controllability on each DoF, long acceleration distance and high power required for jumping. In order to verify the jumping performance of the parallel wire-driven leg structure, we have developed a parallel wire-driven monopedal robot, RAMIEL. RAMIEL is equipped with quasi-direct drive, high power wire winding mechanisms and a lightweight leg, and can achieve a maximum jumping height of 1.6 m and a maximum of seven continuous jumps.

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