scholarly journals Terrestrial force production by the limbs of a semi-aquatic salamander provides insight into the evolution of terrestrial locomotor mechanics

2021 ◽  
Author(s):  
Sandy Momoe Kawano ◽  
Richard W. Blob
Keyword(s):  
Adult Life ◽  
Force Production ◽  
Rear Wheel ◽  
Ambystoma Tigrinum ◽  
Terrestrial Locomotion ◽  
Hind Limbs ◽  
Wheel Drive ◽  
Reaction Forces ◽  
Pleurodeles Waltl ◽  
Insight Into

Amphibious fishes and salamanders are valuable functional analogs for vertebrates that spanned the water-to-land transition. However, investigations of walking mechanics have focused on terrestrial salamanders and, thus, may better reflect the capabilities of stem tetrapods that were already terrestrial. The earliest tetrapods were aquatic, so salamanders that are not primarily terrestrial may yield more appropriate data for modelling the incipient stages of terrestrial locomotion. In the present study, locomotor biomechanics were quantified from semi-aquatic Pleurodeles waltl, a salamander that spends most of its adult life in water, and then compared to a primarily terrestrial salamander (Ambystoma tigrinum) and semi-aquatic fish (Periophthalmus barbarus) to evaluate whether walking mechanics show greater similarity between species with ecological versus phylogenetic similarities. Ground reaction forces (GRFs) from individual limbs or fins indicated that the pectoral appendages of each taxon had distinct patterns of force production, but hind limb forces were comparable between the salamanders. The rate of force development ('yank') was sometimes slower in P. waltl but generally comparable between the three species. Finally, medial inclination of the GRF in P. waltl was intermediate between semi-aquatic fish and terrestrial salamanders, potentially elevating bone stresses among more aquatic taxa as they move on land. These data provide a framework for modelling stem tetrapods using an earlier stage of quadrupedal locomotion that was powered primarily by the hind limbs (i.e., "rear-wheel drive"), and reveal mechanisms for appendages to generate propulsion in three locomotor strategies that are presumed to have occurred across the water-to-land transition in vertebrate evolution.

Equilibrium Analysis of Drifting Vehicles for Control Design

2009 ◽  
Author(s):  
Rami Y. Hindiyeh ◽  
J. Christian Gerdes
Keyword(s):  
Saddle Points ◽  
Operating Regime ◽  
Longitudinal Force ◽  
Rear Wheel ◽  
Equilibrium Analysis ◽  
Bicycle Model ◽  
Wheel Drive ◽  
Force Coupling ◽  
Low Sensitivity ◽  
Insight Into

This paper presents an analysis of the dynamics of a rear wheel drive vehicle during cornering at high sideslip angles (“drifting”) using a three-state bicycle model. This model builds upon previous work with a two-state bicycle model by incorporating longitudinal dynamics and a nonlinear tire model with simplified lateral-longitudinal force coupling. Analysis of this model reveals the existence of unstable “drift equilibria” corresponding to steady state cornering at high sideslip angles with significant longitudinal force applied at the rear tire. These equilibria are saddle points, with characteristics that exhibit low sensitivity to friction and speed variation. The analysis of the equilibria provides insight into vehicle dynamics in an operating regime responsible for major safety concerns in everyday driving. It also sheds light upon aspects of the system dynamics that account for behavior observed in autonomous drift experiments and must be considered in future controller designs.

Development of the Control Strategy for an Innovative 4WD Device

2006 ◽  
Author(s):  
Federico Cheli ◽  
Paolo Dellacha` ◽  
Andrea Zorzutti
Keyword(s):  
Automotive Industry ◽  
Controller Design ◽  
Rear Wheel ◽  
Front Axle ◽  
Torque Distribution ◽  
Actuation System ◽  
Wheel Drive ◽  
Wet Clutch ◽  
The One ◽  
Engine Crankshaft

The potentialities shown by controlled differentials are making the automotive industry to explore this field. While VDC systems can only guarantee a safe behaviour at limit, a controlled differential can also increase the handling performance. The system derives from a rear wheel drive architecture with a semi-active differential, to which has been added a controlled wet clutch that directly connects the front axle and the engine crankshaft. This device allows distributing the drive torque between the two axles, according to the constraints due to kinematics and thermal problems. It can be easily understood that in this device the torque distribution doesn’t depend only from the central clutch action, but also from the engaged gear. Because of that the central clutch controller has to consider the gear position too. The control algorithms development was carried on using a vehicle model which can precisely simulate the handling response, the powertrain dynamic and the actuation system behaviour. A right powertrain response required the development of a customize library in Simulink. The approach chosen to carry on this research was the one used in automotive industry nowadays: an intensive simulation campaign was executed to realize an initial controller design and tuning.

Modeling and Controlling of Anti-Slip Regulation Based on Limited-Slip Differential

2011 ◽  
Vol 86 ◽  
pp. 762-766
Author(s):  
Jian Jun Hu ◽  
Peng Ge ◽  
Zheng Bin He ◽  
Da Tong Qin
Keyword(s):  
Dynamic Models ◽  
Fuzzy Controller ◽  
Rear Wheel ◽  
Pi Controller ◽  
Hydraulic Control ◽  
Electronic Throttle ◽  
Adhesion Coefficient ◽  
The Road ◽  
Wheel Drive ◽  
Hydraulic Control System

The dynamic models of whole rear-wheel drive vehicle, limited-slip differential, hydraulic control system and electronic throttle were established. Simulations of acceleration course on split-µ road, checkerboard-µ road, low-µ road and step-µ road were carried out combining electronic throttle PI controller and limited-slip differential fuzzy controller. The results show that the Anti-slip Regulation quickly works according to the road adhesion coefficient, effectively inhibits the slip of driving wheels on low adhesion coefficient road, the acceleration performance driving on bad roads was improved obviously, and show a good adaptability.

Many-legged maneuverability: dynamics of turning in hexapods

1999 ◽  
Vol 202 (12) ◽  
pp. 1603-1623 ◽  
Author(s):  
D.L. Jindrich ◽  
R.J. Full
Keyword(s):  
Horizontal Plane ◽  
Center Of Mass ◽  
Vertical Plane ◽  
Force Production ◽  
The Body ◽  
Mean Velocity ◽  
Blaberus Discoidalis ◽  
Body Design ◽  
Reaction Forces ◽  
Straight Ahead

Remarkable similarities in the vertical plane of forward motion exist among diverse legged runners. The effect of differences in posture may be reflected instead in maneuverability occurring in the horizontal plane. The maneuver we selected was turning during rapid running by the cockroach Blaberus discoidalis, a sprawled-postured arthropod. Executing a turn successfully involves at least two requirements. The animal's mean heading (the direction of the mean velocity vector of the center of mass) must be deflected, and the animal's body must rotate to keep the body axis aligned with the heading. We used two-dimensional kinematics to estimate net forces and rotational torques, and a photoelastic technique to estimate single-leg ground-reaction forces during turning. Stride frequencies and duty factors did not differ among legs during turning. The inside legs ended their steps closer to the body than during straight-ahead running, suggesting that they contributed to turning the body. However, the inside legs did not contribute forces or torques to turning the body, but actively pushed against the turn. Legs farther from the center of rotation on the outside of the turn contributed the majority of force and torque impulse which caused the body to turn. The dynamics of turning could not be predicted from kinematic measurements alone. To interpret the single-leg forces observed during turning, we have developed a general model that relates leg force production and leg position to turning performance. The model predicts that all legs could turn the body. Front legs can contribute most effectively to turning by producing forces nearly perpendicular to the heading, whereas middle and hind legs must produce additional force parallel to the heading. The force production necessary to turn required only minor alterations in the force hexapods generate during dynamically stable, straight-ahead locomotion. A consideration of maneuverability in the horizontal plane revealed that a sprawled-postured, hexapodal body design may provide exceptional performance with simplified control.

Kinematic and Electromyographic Analysis of the functional role of the body axis during Terrestrial and Aquatic Locomotion in the Salamander Ambystoma Tigrinum

1992 ◽  
Vol 162 (1) ◽  
pp. 107-130 ◽  
Author(s):  
LARRY M. FROLICH ◽  
ANDREW A. BIEWENER
Keyword(s):  
Muscle Activity ◽  
Functional Role ◽  
The Body ◽  
Ambystoma Tigrinum ◽  
Terrestrial Locomotion ◽  
Aquatic Locomotion ◽  
Wave Patterns ◽  
Axial Morphology ◽  
Electromyographic Analysis

Aquatic neotenic and terrestrial metamorphosed salamanders {Ambystoma tigrinum) were videotaped simultaneously with electromyographic (EMG) recording from five epaxial myotomes along the animal's trunk during swimming in a flow tank and trotting on a treadmill to investigate axial function during aquatic and terrestrial locomotion. Neotenic and metamorphosed individuals swim using very similar axial wave patterns, despite significant differences in axial morphology. During swimming, both forms exhibit traveling waves of axial flexion and muscle activity, with an increasing EMG-mechanical delay as these waves travel down the trunk. In contrast to swimming, during trotting metamorphosed individuals exhibit a standing wave of axial flexion produced by synchronous activation of ipsilateral epaxial myotomes along the trunk. Thus, metamorphosed individuals employ two distinct axial motor programs -- one used during swimming and one used during trotting. The transition from a traveling axial wave during swimming to a standing axial wave during trotting in A. tigrinum may be an appropriate analogy for similar transitions in axial locomotor function during theoriginal evolution of terrestriality in early tetrapods.

Twisting and Bending: The Functional Role of Salamander Lateral Hypaxial Musculature During Locomotion

2001 ◽  
Vol 204 (11) ◽  
pp. 1979-1989 ◽  
Author(s):  
Wallace O. Bennett ◽  
Rachel S. Simons ◽  
Elizabeth L. Brainerd
Keyword(s):  
High Intensity ◽  
High Speed ◽  
The Body ◽  
Transversus Abdominis ◽  
Fine Motor ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Terrestrial Locomotion ◽  
Reaction Forces ◽  
Hypaxial Muscle

SUMMARY The function of the lateral hypaxial muscles during locomotion in tetrapods is controversial. Currently, there are two hypotheses of lateral hypaxial muscle function. The first, supported by electromyographic (EMG) data from a lizard (Iguana iguana) and a salamander (Dicamptodon ensatus), suggests that hypaxial muscles function to bend the body during swimming and to resist long-axis torsion during walking. The second, supported by EMG data from lizards during relatively high-speed locomotion, suggests that these muscles function primarily to bend the body during locomotion, not to resist torsional forces. To determine whether the results from D. ensatus hold for another salamander, we recorded lateral hypaxial muscle EMGs synchronized with body and limb kinematics in the tiger salamander Ambystoma tigrinum. In agreement with results from aquatic locomotion in D. ensatus, all four layers of lateral hypaxial musculature were found to show synchronous EMG activity during swimming in A. tigrinum. Our findings for terrestrial locomotion also agree with previous results from D. ensatus and support the torsion resistance hypothesis for terrestrial locomotion. We observed asynchronous EMG bursts of relatively high intensity in the lateral and medial pairs of hypaxial muscles during walking in tiger salamanders (we call these ‘α-bursts’). We infer from this pattern that the more lateral two layers of oblique hypaxial musculature, Mm. obliquus externus superficialis (OES) and obliquus externus profundus (OEP), are active on the side towards which the trunk is bending, while the more medial two layers, Mm. obliquus internus (OI) and transversus abdominis (TA), are active on the opposite side. This result is consistent with the hypothesis proposed for D. ensatus that the OES and OEP generate torsional moments to counteract ground reaction forces generated by forelimb support, while the OI and TA generate torsional moments to counteract ground reaction forces from hindlimb support. However, unlike the EMG pattern reported for D. ensatus, a second, lower-intensity burst of EMG activity (‘β-burst’) was sometimes recorded from the lateral hypaxial muscles in A. tigrinum. As seen in other muscle systems, these β-bursts of hypaxial muscle coactivation may function to provide fine motor control during locomotion. The presence of asynchronous, relatively high-intensity α-bursts indicates that the lateral hypaxial muscles generate torsional moments during terrestrial locomotion, but it is possible that the balance of forces from both α- and β-bursts may allow the lateral hypaxial muscles to contribute to lateral bending of the body as well.

Mechanics of six-legged runners

1990 ◽  
Vol 148 (1) ◽  
pp. 129-146 ◽  
Author(s):  
R. J. Full ◽  
M. S. Tu
Keyword(s):  
Mechanical Energy ◽  
Center Of Mass ◽  
Force Production ◽  
Stride Frequency ◽  
Gravitational Potential Energy ◽  
Vertical Force ◽  
Body Form ◽  
Blaberus Discoidalis ◽  
Ghost Crabs ◽  
Reaction Forces

Six-legged pedestrians, cockroaches, use a running gait during locomotion. The gait was defined by measuring ground reaction forces and mechanical energy fluctuations of the center of mass in Blaberus discoidalis (Serville) as they travelled over a miniature force platform. These six-legged animals produce horizontal and vertical ground-reaction patterns of force similar to those found in two-, four- and eight-legged runners. Lateral forces were less than half the vertical force fluctuations. At speeds between 0.08 and 0.66 ms-1, horizontal kinetic and gravitational potential energy changes were in phase. This pattern of energy fluctuation characterizes the bouncing gaits used by other animals that run. Blaberus discoidalis attained a maximum sustainable stride frequency of 13 Hz at 0.35 ms-1, the same speed and frequency predicted for a mammal of the same mass. Despite differences in body form, the mass-specific energy used to move the center of mass a given distance (0.9 J kg-1m-1) was the same for cockroaches, ghost crabs, mammals, and birds. Similarities in force production, stride frequency and mechanical energy production during locomotion suggest that there may be common design constraints in terrestrial locomotion which scale with body mass and are relatively independent of body form, leg number and skeletal type.

scholarly journals Vehicle Sideslip Angle Estimation Based on Tire Model Adaptation

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 199 ◽  
Author(s):  
Kanwar Bharat Singh
Keyword(s):  
Experimental Tests ◽  
Estimation Algorithm ◽  
Rear Wheel ◽  
Stability Control ◽  
Operating Conditions ◽  
Successful Implementation ◽  
Tire Model ◽  
Sideslip Angle ◽  
Wheel Drive ◽  
Sideslip Estimation

Information about the vehicle sideslip angle is crucial for the successful implementation of advanced stability control systems. In production vehicles, sideslip angle is difficult to measure within the desired accuracy level because of high costs and other associated impracticalities. This paper presents a novel framework for estimation of the vehicle sideslip angle. The proposed algorithm utilizes an adaptive tire model in conjunction with a model-based observer. The proposed adaptive tire model is capable of coping with changes to the tire operating conditions. More specifically, extensions have been made to Pacejka's Magic Formula expressions for the tire cornering stiffness and peak grip level. These model extensions account for variations in the tire inflation pressure, load, tread depth and temperature. The vehicle sideslip estimation algorithm is evaluated through experimental tests done on a rear wheel drive (RWD) vehicle. Detailed experimental results show that the developed system can reliably estimate the vehicle sideslip angle during both steady state and transient maneuvers.

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