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.
| Dimensions (fully stretched legs) | 1.0m x 0.5m x 0.98m (Length x Width x Height) |
| Weight | 70kg (external hydraulic power supply), 90kg (onboard hydraulic power supply) |
| Number of active DOF | 12 (8 hydraulic and 4 electric) |
| Actuator Types | Hydraulic cylinders (80mm stroke, 16mm bore) and DC brushless motors with harmonic gear |
| Joint range of motion | 120° |
| Maximum torque (electric) | 152Nm (torque limit of gear) |
| Maximum torque (hydraulic) | 145Nm (peak torque at max. pressure of 16MPa) |
| Onboard sensors | High-resolution position and torque on each joint, cylinder chamber pressure, inertial measurement unit (IMU), hydraulic system |
| Onboard computer | PC104 Pentium, real-time Linux (Xenomai) |
| Control frequency | 1 kHz |
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.
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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.
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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).
Capabilities
- Walk, trot and run up to 2m/s
- Rear and jump up to 0.5m from squat
- Balance under unstable ground even under disturbance
- Torque and position-controlled joints
- Indoor and outdoor operation
- Real-time control system with dynamics simulator
Future Applications
- Search and rescue operations
- Operations in contaminated and dangerous areas
- Forestry, construction and firefighting application
- Inspection and exploration tasks
- Experimental platform for legged robotics research (e.g. legged locomotion, biomechanics, force control, autonomous navigation)
Involved People ...
and
Jake Goldsmith, Nikos Tsagarakis, Emanuele Guglielmino, Ferdinando Cannella, and Prof. Darwin Caldwell
... and our team of technicians
Marco Migliorini, Stefano Cordasco, Phil Hudson, Carlo Tacchino (electronics)
Gianluca Pane and Giuseppe Sofia (mechanics)
Alessio Margan (software)
Collaborating Groups
Agile & Dexterous Robotics Lab, Swiss Federal Institute of Technology (ETH)
Departamento de Automação e Sistemas, Universidade Federal de Santa Catarina, Florianopolis, Brazil
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
Downloads
HyQ_MechanicalStructure_front.jpg
HyQ_MechanicalStructure_side.jpg
Videos
HyQ Robot - Hopping Leg Prototype
HyQ - IIT's Hydraulic Quadruped Robot - Introduction
HyQ - Balancing and First Outdoor Tests NEW! May 2012
Software
We use the SL simulator and motor controller package for our robot (you can find a technical report about it at this page)At this page, you can also download a distribution of the code generator for kinematics and dynamics that we are developing as part of our research.
List of Publications
Dissertations
2010
- C. Semini, "HyQ – Design and Development of a Hydraulically Actuated Quadruped Robot,” Dissertation, Italian Institute of Technology and University of Genoa, Italy, 2010.
[full thesis]
Journal, Conference Papers and Posters
2013
- V. Barasuol, J. Buchli, C. Semini, M. Frigerio, E. R. De Pieri, D. G. Caldwell, "A Reactive Controller Framework for Quadrupedal Locomotion on Challenging Terrain", IEEE International Conference on Robotics and Automation (ICRA), 2013.
[full article] - T. Boaventura, C. Semini, J. Buchli and D. G. Caldwell, "Mechanical and Control Design Issues in Hydraulic Compliance Control", ext. abstract at the workshop on Design and Control of High-Performance Hydraulic Robots: Recent Advances and Perspectives at IEEE ICRA, 2013.
- M. Frigerio, C. Semini, D. G. Caldwell, J. Buchli, "Challenges in the software architecture design for autonomous legged robots", ext. abstract for the 8th workshop on Software Development and Integration in Robotics (SDIR VIII) at IEEE ICRA, 2013.
- M Focchi, V. Barasuol, I. Havoutis, J. Buchli, C. Semini and D. G. Caldwell, "Local Reflex Generation for Obstacle Negotiation in Quadrupedal Locomotion", Int. Conf. on Climbing and Walking Robots (CLAWAR), 2013. (accepted)
- H. Khan, C. Semini, V. Barasuol, D. G. Caldwell, "Actuator sizing for highly-dynamic quadruped robots based on squat jumps and running trots", Int. Conf. on Climbing and Walking Robots (CLAWAR), 2013. (accepted)
- M. A. Arain, I. Havoutis, C. Semini, J. Buchli and D. G. Caldwell, "A comparison of Search-based Planners for a Legged Robot. IEEE International Workshop on Robot Motion and Control (RoMoCo), 2013. (accepted)
- I. Havoutis, C. Semini, D. G. Caldwell, "Virtual model control for quadrupedal trunk stabilization", Dynamic Walking, 2013. (accepted)
- S. Bazeille, V. Barasuol, M. Focchi, I. Havoutis, M. Frigerio, J. Buchli, C. Semini, D. G. Caldwell, "Vision Enhanced Reactive Locomotion Control for Trotting on Rough Terrain", IEEE International Conference on Technologies for Practical Robot Applications (TePRA), 2013.
[full article] - H. Khan, C. Semini, D. G. Caldwell, "Scaling of versatile quadruped robots for running trot", Proceedings 6th International Symposium in Adaptive Motion of Animals and Machines (AMAM), 2013.
[extended abstract] - I. Havoutis, C. Semini, J. Buchli, D. G. Caldwell, "Quadrupedal trotting with active compliance ", IEEE International Conference on Mechatronics (ICM), 2013.
[full article]
2012
- T. Boaventura, M. Focchi, M. Frigerio, J. Buchli, C. Semini, G. A. Medrano-Cerda, D. G. Caldwell, "On the role of load motion compensation in high-performance force control", IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2012.
[full article] - M. Frigerio, J. Buchli and D. G. Caldwell, "Code Generation of Algebraic Quantities for Robot Controllers", IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2012.
[full article] - I. Havoutis, C. Semini, J. Buchli and D.G. Caldwell, "Progress in quadrupedal trotting with active compliance", Dynamic Walking 2012, Pensacola, Florida, USA.
[extended abstract] - C. Semini, H. Khan, M. Frigerio, T. Boaventura, M. Focchi, J. Buchli and D. G. Caldwell, "Design and Scaling of Versatile Quadruped Robots", Int. Conf. on Climbing and Walking Robots (CLAWAR), 2012.
[full article] - T. Boaventura, C. Semini, J. Buchli, M. Frigerio, M. Focchi, D. G. Caldwell, "Dynamic Torque Control of a Hydraulic Quadruped Robot", Proceedings IEEE International Conference on Robotics and Automation (ICRA), 2012, St. Paul, USA.
[full article]
- M. Frigerio, J. Buchli and D. G. Caldwell, "Model based code generation for kinematics and dynamics computations in robot controllers", 7th workshop on Software Development and Integration in Robotics (ICRA SDIR VII), St Paul, Minnesota, USA, May 2012.
[extended abstract] - M. Focchi, T. Boaventura, C. Semini, M. Frigerio, J. Buchli, D. G. Caldwell, "Torque-control Based Compliant Actuation of a Quadruped Robot", Proceedings of the 12th IEEE International Workshop on Advanced Motion Control (AMC), Sarajevo, Bosnia and Herzegovina, 2012.
[full article] - S. Peng, D. T. Branson, E. Guglielmino, T. Boaventura, and D. G. Caldwell, "Performance Assessment of Digital Hydraulics in a Quadruped Robot Leg", Proceedings of the 11th Biennial Conference on Engineering Systems Design and Analysis ESDA11, 2012.
[full article]
2011
- T. Boaventura, C. Semini, J. Buchli, D. G. Caldwell, "Actively-compliant leg for dynamic locomotion", Proceedings 5th International Symposium in Adaptive Motion of Animals and Machines (AMAM), 2011, Hyogo, Japan.
[full article]
- M. Frigerio, J. Buchli and D. G. Caldwell, "A Domain Specific Language for kinematic models and fast implementations of robot dynamics algorithms", 2nd International Workshop on Domain-Specific Languages and models for ROBotic systems (DSLRob’11), San Francisco, September 2011.
[full article]
- 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,” Journal of Systems and Control Engineering, vol. 225, no. 6, pp. 831–849, 2011.
[full article]
- 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.
[full article]
2010
- 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.
[full article] - C. Semini, N. Tsagarakis, E. Guglielmino and D. G. Caldwell, "Design and experimental evaluation of the hydraulically actuated prototype leg of the HyQ robot", International Conference on Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ.
[full article] - C. Semini, N. Tsagarakis, E. Guglielmino, D. G. Caldwell, "Design of a Hydraulic Quadruped Robot," Workshop on Human Adaptive Mechatronics (HAM), 2010.
- T. Boaventura, C. Semini, E. Guglielmino, V. J. De Negri, Y. Yang, D. G. Caldwell, “Gain Scheduling Control for the Hydraulic Actuation of the HyQ Robot Leg”, ABCM Symposium Series in Mechatronics, vol. 4, pp. 673-682, 2010.
[full article] - Y. Yang, E. Guglielmino, J. S. Dai, T. Boaventura, and D. G. Caldwell, "Modeling of a novel 3-way rotary type electro-hydraulic valve," in Proc. IEEE Int. Conf. Information and Automation (ICIA) Conf, 2010, pp. 1463-1468.
[full article]
2009
- 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.
[full article] - 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.
[full article] - 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.
[full article]
2008
- 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.
[full article] - 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.
[poster] - 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.
[full article]
Contact:
Claudio Semini,
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, +39 010 71781 912
Darwin Caldwell,
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, +39 010 71781 427/407
