HyQ is a fully torque-controlled Hydraulically actuated Quadruped robot (pronounced [hai-kju:]) developed in the Department of Advanced Robotics at the IIT. HyQ is designed to move over rough terrain and perform highly dynamic tasks such as jumping and running with different gaits (up to 3-4m/s). To achieve the required high joint speeds and torques, a combination of hydraulic cylinders and electric motors are actuating the robot’s 12 active joints.

Goals of the project are the investigation of various aspects of quadrupedal locomotion, adjustable compliance, energy efficiency, compact hydraulic actuation and onboard power systems.

System Overview

The following table lists the key specifications of the robot platform.

Figure 2 shows the CAD model of the robot and 2 pictures with different views of HyQ’s mechanical skeleton built in aerospace-grade aluminium alloy and stainless steel. The robot’s torso is built with a folded aluminium alloy sheet with internal walls to achieve high torsional robustness.

Figure 2: CAD model of HyQ with onboard hydraulic system (left) and pictures of the mechanical skeleton of HyQ (centre and right).

Leg Design

Each leg features three degrees of freedom (DOF), two in the hip (abduction/adduction and flexion/extension) and one in the knee (flexion/extension). The leg is built of a light-weight aerospace-grade aluminium alloy and stainless steel. High resolution encoders and load cells in each joint allow a smooth control of both position and torque. We are currently designing and testing several foot designs with and without adjustable stiffness to soften the impacts at foot touch-down and to store energy from one step to the next.

Figure 3: Leg Design Evolution: CAD model and picture of HyQ leg prototype (left) and the improved final leg (right)

In the beginning of 2008, we successfully reached the first milestone of the project: The design and construction of a first 2-DOF leg prototype (Fig. 3, left) with an actuated hip and knee joint in the sagittal plane (Semini et al., 2008). Since then, we have extensively used the leg to test its mechanical structure, the hydraulic actuation system and to evaluate various joint level controllers (Semini et al, 2008; Cunha et al, 2009; Focchi et al, 2010). For the experiments the leg was either mounted to a vertical slider or fixed to a work bench. We studied the behavior of the mechanical structure and hydraulics upon leg impact with varying leg weights up to 25kg. Furthermore, we tested the leg during continuous hopping with different frequencies up to 3Hz, since hopping is a simplified form of running (see video).

The experiments proofed that hydraulic actuation is very suitable for highly dynamic legged robots, due to its high power-to-weight ratio, high torque and speed and ability to cope with torque peaks (Semini, 2010).

Coming next

• System testing and first walking/running experiments on a treadmill.
• Study of Locomotion with a focus on rough terrain walking and balancing.
• Study of highly dynamic motions (e.g. jumping and running trot with 3-4m/s)
• Study of energy efficient locomotion (e.g. evaluation of different foot designs with/without adjustable stiffness and/or damping).
• Development and evaluation of compact and energy-efficient hydraulic components (Guglielmino et al, 2009).
• Investigation of water hydraulic actuation systems for robotics
• Power-autonomous version of HyQ.

Involved People

Claudio Semini, Jonas Buchli, Ioannis Havoutis, Nikos Tsagarakis, Emanuele Guglielmino, Ferdinando Cannella, David Branson, Thiago Boaventura, Michele Focchi, Marco Frigerio, Peng Shuang and Prof. Darwin Caldwell

and our team of technicians

Carlo Tacchino, Marco Migliorin, Stefano Cordasco (electronics)

Jake Goldsmith, Gianluca Pane and Giuseppe Sofia (mechanics)

Alessio Margan (software)

Collaborating Groups

Computational Learning and Motor Control Lab (CLMC lab), University of Southern California, USA

Centre for Power Transmission and Motion Control, University of Bath, UK

Department of Intelligent Hydraulics and Automation, Tampere University of Technology, Finland

Institute of Machine Design and Hydraulic Drives, Johannes Kepler University of Linz, Austria

Robotics Lab, Carlos III University of Madrid, Spain

Downloads

HyQ_MechanicalStructure_front.jpg

HyQ_MechanicalStructure_side.jpg

Videos

HyQ Robot - Hopping Leg Prototype

HyQ - IIT's Hydraulic Quadruped Robot - Introduction

List of Publications

Dissertations

C. Semini, "HyQ – Design and Development of a Hydraulically Actuated Quadruped Robot,” Dissertation, Italian Institute of Technology and University of Genoa, Italy, 2010.

Journal, Conference Papers and Posters

C. Semini, N. G. Tsagarakis, E. Guglielmino, M. Focchi, F. Cannella, and D. G. Caldwell, “Design of HyQ - a hydraulically and electrically actuated quadruped robot,” IMechE Part I: J. of Systems and Control Engineering, vol. 225, no. 6, pp. 831–849, 2011.

C. Semini, J. Buchli, M. Frigerio, T. Boaventura, M. Focchi, E. Guglielmino, F. Cannella, N. G. Tsagarakis, and D. G. Caldwell, “HyQ – a dynamic locomotion research platform,” in Int.l Workshop on Bio-Inspired Robots, Nantes (France), 2011.

C. Semini, N. G. Tsagarakis, B. Vanderborght, Y. S. Yang and D. G. Caldwell, "HyQ - Hydraulically Actuated Quadruped Robot: Hopping Leg Prototype," IEEE/RAS-EMBS Int. Conf. on Biomedical Robotics and Biomechatronics (BioRob), pp.593-599, 2008.

C. Semini, N. G. Tsagarakis, D. G. Caldwell, "Dynamic Tasks of a Hydraulically Actuated Quadruped Robot," Poster at Dynamic Walking Conference, Delft (The Netherlands), May 2008.

C. Semini, N. G. Tsagarakis, D. G. Caldwell, "Bio-Inspired Design of a Hydraulically Actuated Quadruped Robot [HyQ]," Poster at Robotics: Science and Systems (RSS) Conference, Zurich (Switzerland), June 2008.

Y. S. Yang, C. Semini, N. G. Tsagarakis, D. G. Caldwell, Y. Zhu, "Water hydraulics - A novel design of spool-type valves for enhanced dynamic performance," IEEE/ASME Int. Conf. on Advanced Intelligent Mechatronics (AIM), pp. 1308-1314, 2008.

Y. S. Yang, C. Semini, E. Guglielmino, N. G. Tsagarakis, D. G. Caldwell, "Water vs. Oil Hydraulic Actuation for a Robot Leg," IEEE Int. Conf. on Mechatronics and Automation (ICMA), pp. 1940-1946, 2009.

Y. S. Yang, C. Semini, N. G. Tsagarakis, E. Guglielmino, D. G. Caldwell, "Leg Mechanisms for Hydraulically Actuated Robots," IEEE/RSJ Int. Conf. on Intelligent RObots and Systems (IROS), pp. 4669-4675, 2009.

E. Guglielmino, C. Semini, Y. S. Yang, D. G. Caldwell, H. Kogler, R. Scheidl, "Energy Efficient Fluid Power in Autonomous Legged Robotics," ASME Dynamic Systems and Control Conference (DSCC), 2009.

T. B. Cunha, C. Semini, E. Guglielmino, V. J. De Negri, Y. S. Yang, D. G. Caldwell, "Gain Scheduling Control for the Hydraulic Actuation of the HyQ Robot Leg," Int. Conf. of Mechanical Engineering (COBEM), 2009.

M. Focchi, E. Guglielmino, C. Semini, T. Boaventura, Y. S. Yang, D. G. Caldwell, "Control of a Hydraulically-Actuated Quadruped Robot Leg," IEEE Int. Conf. on Robotics and Automation (ICRA), 2010.

C. Semini, N. Tsagarakis, E. Guglielmino, D. G. Caldwell, "Design of a Hydraulic Quadruped Robot," Workshop on Human Adaptive Mechatronics (HAM), 2010.

Contact:

Claudio Semini, This e-mail address is being protected from spambots. You need JavaScript enabled to view it , +39 010 71781 912

Jonas Buchli, This e-mail address is being protected from spambots. You need JavaScript enabled to view it , +39 010 71781 925

Darwin Caldwell, This e-mail address is being protected from spambots. You need JavaScript enabled to view it , +39 010 71781 427/407