Quadrupedal running at high speed over uneven terrain

2007 ◽  
Author(s):  
Luther R. Palmer ◽  
David E. Orin
Keyword(s):  
High Speed ◽  
Uneven Terrain

Control of ATRIAS in three dimensions: Walking as a forced-oscillation problem

2020 ◽  
Vol 39 (7) ◽  
pp. 774-796
Author(s):  
Siavash Rezazadeh ◽  
Jonathan W Hurst
Keyword(s):  
Feedback Linearization ◽  
High Speed ◽  
Forced Oscillation ◽  
Vertical Motion ◽  
Three Dimensions ◽  
Singular Perturbation Theory ◽  
Foot Placement ◽  
Uneven Terrain ◽  
Walking Control ◽  
The Stability

In this article, we present a new controller for stable and robust walking control of ATRIAS, an underactuated bipedal robot designed based on the spring-loaded inverted pendulum (SLIP) model. We propose a forced-oscillation scheme for control of vertical motion, which we prove to be stable and contractive. Moreover, we prove that, through some mild assumptions, the dynamics of the system can be written in a hierarchical form that decouples the stability analyses of the horizontal and vertical directions. We leverage these properties to find a stabilizing class of functions for foot placement. The torso control is also proved to be decoupled using singular perturbation theory and is stabilized through a feedback linearization controller. We also take advantage of the proposed framework’s flexibility and extend it to include a new reflex-based uneven-terrain walking control scheme. We test the controller for various desired walking speeds (0 to 2.5 m/s), for stepping up and down unexpected obstacles (15 cm), and for high-speed walking on a random uneven terrain (up to 10 cm of step-ups and step-downs and up to 1.8 m/s). The results show successful performance of the controller and its stability and robustness against various perturbations.

Assessment of the Dynamic Behavior of a Single Person ATV in Presence of a Passenger: Outcome on the Rider and Passenger Crash Impact Kinematics Using Computational Model

2012 ◽  
Author(s):  
Chandrashekhar K. Thorbole ◽  
Mary Aitken ◽  
James Graham ◽  
Beverly Miller ◽  
Samantha Hope Mullins
Keyword(s):  
Computational Model ◽  
Injury Prevention ◽  
High Speed ◽  
Tilt Table ◽  
Child Injury ◽  
Uneven Terrain ◽  
Handling Characteristics ◽  
Single Person ◽  
Child Injury Prevention ◽  
Multi Body

An ATV (All-terrain vehicle) is a gasoline powered, fast moving off road vehicle often used for farming and industrial activities as well as recreational activities. The popularity of this type of vehicle has increased over the last decade with more than 10 million in use today. Most ATVs are designed for only single rider even though the seat of the ATV may appear big enough to carry a passenger. The presence of an additional person on a single person ATV greatly affects its dynamic handling characteristics. This change increases the risk of a crash and subsequent injuries to both riders. ATV crashes involving climbing and descending on steep hills are common. Lateral rollover crashes are often the result of riding an ATV at a high speed on uneven terrain. The presence of passenger on a single person ATV during these conditions changes the rider impact kinematics and resulting injury outcome, as the ATV behaves differently in the presence of an additional person. The computational model of a single person, adult-sized ATV, as developed previously for the study of child injury prevention, was used for this study. The multi-body computational model of this ATV was developed using biodynamic code MADYMO. This computational model was validated against the laboratory test for its dynamic and suspension characteristics. The tilt table test and the drop test were employed to compare the computational model result. This computer model was used to simulate the crash mechanism involving climbing and descending steep hills with two people on the ATV. This model was also used to simulate the lateral rollover of ATV with two people. The rider and the additional passenger on this single rider ATV were modeled using a 50th percentile male and a 5th percentile female. The two rider simulation was compared with single rider simulation for similar terrain and ATV speed to gain insight about the influence of this additional passenger weight on the crash kinematics of the ATV and the rider. These simulations will also be used in the future to generate more visually dramatic videos for educational intervention for ATV safety programs and other injury prevention activities.

scholarly journals Dynamic Rocker-Bogie: Kinematical Analysis in a High-Speed Traversal Stability Enhancement

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Sunxin Wang ◽  
Yan Li
Keyword(s):  
High Speed ◽  
Stability Margin ◽  
Suspension System ◽  
Rough Terrain ◽  
Operating Modes ◽  
Uneven Terrain ◽  
Major Shortcoming ◽  
Stability Enhancement ◽  
Travel Rate ◽  
Original Configuration

The rocker-bogie suspension system has robust capabilities to deal with uneven terrain because of its distributing of the payload over its six wheels uniformly, while there is one major shortcoming to high-speed traversal over the planar terrain. This paper proposes a new dynamic rocker-bogie suspension system with two modes of operation: it can expand the span of the rocker-bogie support polygon to increase travel rate when the terrain is planar; and it can switch to its original configuration to move by low speed when it is faced with rough terrain. The analysis on dynamic stability margin and kinematical simulation on the two operating modes of rocker-bogie are employed to analyze and verify the rationality and effectiveness of the modification in the structure.

scholarly journals Small vertebrates running on uneven terrain: a biomechanical study of two differently specialised lacertid lizards

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
François Druelle ◽  
Jana Goyens ◽  
Menelia Vasilopoulou-Kampitsi ◽  
Peter Aerts
Keyword(s):  
High Speed ◽  
Mechanical Energy ◽  
Small Animals ◽  
Podarcis Muralis ◽  
Cost Of Transport ◽  
Running Performance ◽  
Uneven Terrain ◽  
Hind Limbs ◽  
Custom Made ◽  
Lacertid Lizards

AbstractWhile running, small animals frequently encounter large terrain variations relative to their body size, therefore, terrain variations impose important functional demands on small animals. Nonetheless, we have previously observed in lizards that running specialists can maintain a surprisingly good running performance on very uneven terrains. The relatively large terrain variations are offset by their capacity for leg adjustability that ensures a ‘smooth ride’ of the centre of mass (CoM). The question as to how the effect of an uneven terrain on running performance and locomotor costs differs between species exhibiting diverse body build and locomotor specializations remains. We hypothesise that specialized runners with long hind limbs can cross uneven terrain more efficiently than specialized climbers with a dorso-ventrally flattened body and equally short fore and hind limbs. This study reports 3D kinematics using high-speed videos (325 Hz) to investigate leg adjustability and CoM movements in two lacertid lizards (Acanthodactylus boskianus, running specialist; Podarcis muralis, climbing specialist). We investigated these parameters while the animals were running on a level surface and over a custom-made uneven terrain. We analysed the CoM dynamics, we evaluated the fluctuations of the positive and negative mechanical energy, and we estimated the overall cost of transport. Firstly, the results reveal that the climbers ran at lower speeds on flat level terrain but had the same cost of transport as the runners. Secondly, contrary to the running specialists, the speed was lower and the energy expenditure higher in the climbing specialists while running on uneven terrain. While leg movements adjust to the substrates’ variations and enhance the stability of the CoM in the running specialist, this is not the case in the climbing specialist. Although their legs are kept more extended, the amplitude of movement does not change, resulting in an increase of the movement of the CoM and a decrease in locomotor efficiency. These results are discussed in light of the respective (micro-)habitat of these species and suggest that energy economy can also be an important factor for small vertebrates.

Hexapod Locomotion of a Leg-Wheel Hybrid Mobile Robot

2014 ◽  
Vol 658 ◽  
pp. 581-586
Author(s):  
Alina Conduraru Slatineanu ◽  
Ioan Doroftei ◽  
Ionel Conduraru ◽  
Dorin Luca
Keyword(s):  
High Speed ◽  
Real Life ◽  
Control Algorithms ◽  
Wheeled Robots ◽  
Flat Surfaces ◽  
Uneven Terrain ◽  
Difficult Terrain ◽  
Hybrid Locomotion ◽  
And Control ◽  
Wheeled Vehicles

Legged vehicles are more flexible and mobile on difficult terrain, comparing to wheeled robots. Wheels are convenient on flat surfaces or specially prepared surfaces, wheeled vehicles being faster than legged ones. Also, wheeled robots are simpler in terms of mechanical architecture and control algorithms. But they do not perform well on uneven terrain, which is the case in real life, legged robots becoming more interesting to research and explore. This is why hybrid locomotion systems have been developed, in order to exploit the terrain adaptability of legs in rough terrain and simpler control as well as high speed associated with wheels. In this paper some design and kinematic aspects as well as hexapod locomotion of a small hybrid robot are presented.

scholarly journals Design of an active device for controlling lateral stability of fast mobile robot

Robotica ◽  
2015 ◽  
Vol 34 (11) ◽  
pp. 2629-2651 ◽  
Author(s):  
M. Krid ◽  
F. Benamar ◽  
Z. Zamzami
Keyword(s):  
Predictive Control ◽  
High Speed ◽  
Experimental Validation ◽  
Load Transfer ◽  
Modular Design ◽  
Field Tests ◽  
Active Device ◽  
Uneven Terrain ◽  
Roll System ◽  
Virtual Platform

SUMMARYMotivated by the trade-off between speed and stability for off-road navigation, a novel active anti-roll system has been developed in the context of a multidisciplinary project which aims at developing a high-speed and agile autonomous off-road rover. This paper presents the design, simulation and experimental validation of an active anti-roll system and its associated control. The proposed system possess the advantage of having a modular design that can be installed on any off-road chassis with independent suspensions. The proposed system controls directly the roll angle of the rover which is usually uncontrollable in conventional vehicles, hence improving off-road stability while maneuverings at high speed over uneven terrain. Furthermore, the control of the proposed active anti-roll system is based on a model predictive control (MPC) for the roll dynamics, which minimizes the load transfer during cornering and the energy consumed by the actuators. The control model is based on a dynamic model of the rover and on a stability criteria defined by the lateral load transfer (LLT). Moreover, this paper presents, simulation results from the high fidelity virtual platform modeled inMSC.Adams®, as well as, results from recent field tests demonstrating the effectiveness of a hydraulic active anti-roll system mounted on, an especially developed experimental platform, SPIDO ROBOT while cornering at a high speed reaching 8 m/s.

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