HyQ - a dynamic locomotion research platform (original) (raw)
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Compliant quadruped locomotion over rough terrain
2009
Abstract Many critical elements for statically stable walking for legged robots have been known for a long time, including stability criteria based on support polygons, good foothold selection, recovery strategies to name a few. All these criteria have to be accounted for in the planning as well as the control phase. Most legged robots usually employ high gain position control, which means that it is crucially important that the planned reference trajectories are a good match for the actual terrain, and that tracking is accurate.
Dynamically stable legged locomotion
1989
Abstract: This report documents our study of active balance in dynamic legged systems. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of animal locomotion. ...
Design of HyQ -A hydraulically and electrically actuated quadruped robot
A new versatile hydraulically powered quadruped robot (HyQ) has been developed to serve as a platform to study not only highly dynamic motions, such as running and jumping, but also careful navigation over very rough terrain. HyQ stands 1m tall, weighs roughly 90 kg, and features 12 torque-controlled joints powered by a combination of hydraulic and electric actuators. The hydraulic actuation permits the robot to perform powerful and dynamic motions that are hard to achieve with more traditional electrically actuated robots. This paper describes design and specifications of the robot and presents details on the hardware of the quadruped platform, such as the mechanical design of the four articulated legs and of the torso frame, and the configuration of the hydraulic power system. Results from the first walking experiments are presented, along with test studies using a previously built prototype leg. © Authors 2011.
Towards dynamic step climbing for a quadruped robot with compliant legs
2000
1 ABSTRACT Animals are capable of breathtaking dynamic rough terrain mobility–far superior to that of any existing wheeled, tracked or legged robot. Our research aims to endow our legged robots with increasingly capable dynamic abilities. In this paper, we are presenting a controller that expands the rough terrain abilities of our four-legged robot, Scout II, to dynamic step climbing.
Controlling Dynamic Stability and Active Compliance to Improve Quadrupedal Walking
Climbing and Walking Robots, 2006
It is widespread the idea that animal legged locomotion improves wheeled locomotion on very rough terrain. However, the use of legs as locomotion system for vehicles and robots is still far away from competing with wheels and trucks even on natural ground. Walking robots feature two main disadvantages. One is the lack of reacting capabilities from external disturbances, and the other is the very slow walking motion. Both obstacles prevent walking mechanisms from being introduced in industrial processes and from being part of service and assistance robotics. This paper is aimed at solving the two above obstacles by combining a dynamic stability margin that quantifies the impact energy that a robot can withstand, and either controlling a dynamic walk by means of active compliance, which helps the robot react to disturbances. Experiments performed on the SILO4 quadruped robot show a relevant improvement on the walking gait.
Comprehensive locomotion performance evaluation of all-terrain robots
2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-12, 2006
Information about the locomotion performance of known rovers is sparse. A comprehensive evaluation of wheeled passive systems is presented in this work. It is based on a static 2D approach that includes optimization of the wheel torques in order to minimize the required friction which is an important performance metric. The evaluation comprises well known rover concepts and new suspension systems. The performance of the systems is compared and interesting effects of some concepts are discussed in more detail including torques and load distribution. The rovers MER (NASA) and CRAB (EPFL) show good performance which is topped only by the eight wheeled Dou-bleSpring system.
2013
We present the design of a novel compliant quadruped robot: Cheetahcub, and a series of locomotion experiments with fast trotting gaits. The robot's leg configuration is based on a spring-loaded, pantograph mechanism with multiple segments. A dedicated open loop locomotion controller was derived and implemented. Experiments were run in simulation and in hardware on flat terrain and with a step-down, demonstrating the robot's self-stabilizing properties. The robot reached a running trot with short flight phases with a maximum Froude number of FR=1.30, or 6.9 body lengths per second. Morphological parameters such as the leg design also played a role. By adding distal in-series elasticity, self-stability and maximum robot speed improved. Our robot has several advantages, especially when compared to larger and stiffer quadruped robot designs. 1) It is, to the best of our knowledge, the fastest of all quadruped robots below 30 kg (in terms of Froude number and body lengths per second). 2) It shows self-stabilizing behavior over a large range of speeds with open loop control. 3) It is lightweight, compact, electrically powered. 4) It is cheap, easy to reproduce, robust, and safe to handle. This makes it an excellent tool for research of multi-segment legs in quadruped robots.
Systematic Method for Kinematics Modeling of Legged Robots on Uneven Terrain
2009
The paper develops a systematic method for kinematics modeling of multi-legged robots for walking on rough terrain. An extended D-H table is proposed for characterizing the robot joints and linkages parameters that capture the motion. The equations of motions are set up using this table for different frames starting from the robot reference frame, going through individual legs and finally reaching feet-terrain contact frames. The composite equation of motion is formed from those of individual legs. The formulation allows determining actuations to various joints for achieving a desired robot motion, while optimizing a performance index such as a stability measure. For illustration, the method is applied to SILO4, an articulated quadruped.