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This work deals with the problem of force/position trajectory tracking under uncertainties arising from surface position and orientation. A robotic finger with a soft hemispherical tip of uncertain compliance parameter is considered in contact with a rigid flat surface. A novel adaptive controller is designed using online estimates of the unknown parameters and is proved to achieve force and position...
This paper deals with the problem of autonomous navigation for nonholonomic mobile robots. To avoid obstacles while executing a planned motion, we use a nonholonomic trajectory deformation method. Initially, this method did not take into account the velocity and acceleration bounds of the robot. The contribution of this paper is a significant improvement of the method to take into account these kinematic...
Skid-steered mobile robots have been widely used for terrain exploration and navigation. In this paper, we present an adaptive trajectory control design for a skid-steered wheeled mobile robot. Kinematic and dynamic modeling of the robot is first presented. A pseudo-static friction model is used to capture the interaction between the wheels and the ground. An adaptive control algorithm is designed...
We present a novel motion planning algorithm that efficiently generates physics-based samples in a kinematically and dynamically constrained space of a highly articulated chain. Similar to prior kinodynamic planning methods, the sampled nodes in our roadmaps are generated based on dynamic simulation. Moreover, we bias these samples by using constraint forces designed to avoid collisions while moving...
In this paper, two experimental case studies performed with a multi-robot system made of 6 Khepera II mobile robots are presented. The experiments, performed at the laboratory LAI (Laboratorio di Automazione Industriale) of the Universita degli Studi di Cassino, are aimed at testing the performances and the robustness of a behavior-based technique, namely the null-space-based behavioral control (NSB),...
In this paper, we present an efficient method for finding collision-free trajectory for multiple unmanned aerial vehicles (UAVs) with kinematic constraints and for their rendezvous to form a formation. First, we construct a visibility graph that supports a minimum turning radius constraint when constructing the graph, so that additional smoothing process is not necessary. Second, we modify the standard...
Blimp-type unmanned aerial vehicles (BUAVs) does not consume any energy in keeping their longitudinal position in the air, so their use as a platform for mine searching missions is anticipated. For mine searching missions, a BUAV must fly near the ground. Because there is severe limitation on the weight of equipment, such as sensors and actuators, most BUAVs are so-called under-actuated robots. For...
Path planning for formations of wheeled mobile robots (WMRs) has been an active research topic of robotics in the recent years. The methods of route generation for WMRs usually utilize complex algorithms, which require global information of the workspace or mapping of the nearby environment. Hence they are not very efficient for formation based motion of large collections of small entry-level agents...
In this paper, a vision based tracking controller with adaptation to uncertainty in depth information is presented. Depth uncertainty plays a special role in visual tracking as it appears nonlinearly in the overall Jacobian matrix and hence cannot be adapted together with other uncertain kinematic parameters. We propose a novel parameter update law to update the uncertain parameters of the depth....
This paper presents a method of integrating kinematic mechanism design and hybrid system analysis for the design of a single-degree-of-freedom (DOF) planar biped robot that can achieve dynamic walking gaits that are stable. Reducing the DOF in a biped can result in a reduction of the complexity of the control strategies needed to enable stable walking. Although the biped designed by this procedure...
Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics...
A coverage algorithm is an algorithm that deploys a strategy as to how to cover all points in terms of a given area using some set of sensors. In the past decades a lot of research has gone into development of coverage algorithms. Initially, the focus was coverage of structured and semi-structured indoor areas, but with time and development of better sensors and introduction of GPS, the focus has...
In this paper, we develop a prototype of a new snake-like robot using the screw drive mechanism, and design a control system design for trajectory tracking. First, we explain the outline of the snake-like robot using the screw drive units and joint units, as well as the principle of the screw drive mechanism. Next, in order to achieve the trajectory tracking of the robot, we derive a kinematic model...
Previous isotropy analysis of a caster wheeled omnidirectional mobile robot (COMR) has been made under the assumption that the steering link offset is equal to the caster wheel radius. Nevertheless, many practical COMRs in use take advantage of the steering link offset different from the wheel radius. This paper presents a systematic isotropy analysis of a fully actuated COMR with variable steering...
Passive dynamics plays an important role in legged locomotion of the biological systems. The use of passive dynamics provides a number of advantages in legged locomotion such as energy efficiency, self-stabilization against disturbances, and generating gait patterns and behavioral diversity. Inspired from the theoretical and experimental studies in biomechanics, this paper presents a novel bipedal...
This paper presents an analysis on wheeled mobile robots in the presence of wheel skidding and slipping from the perspective of control design. The analysis is based on the kinematic models that are recently developed from control perspective (Wang and Low 2006). Four generic mobile robots are considered in this analysis. We relate the robot's maneuverability with its controllability which provides...
In this paper, we present the dynamic modeling of a 3D-hybrid underwater eel-like robot using recursive algorithms based on the Newton-Euler equations. The robot is composed of a sequence of parallel modules connected in series. The algorithm gives the head accelerations and the joint torques as a function of the Cartesian positions, velocities and accelerations of the platform of the modules. The...
This paper presents the design and fabrication of a robotic ostraciiform. The robot's design is inspired by the highly stable and fairly maneuverable boxfish. Boxfish with its multiple fins can maneuver in confined spaces with a near zero turning radius and it has been found that its unusual boxy shape is responsible for a self correcting mechanism that makes its trajectories immune to water disturbances...
This paper presents a method for the control of locomotion in a robot hexapod. The approach is based on the WalkNet structure, which in turn is based on the neural control structure of the insect Carausius morosus. Though the WalkNet structure has been shown to function well in kinematic (i.e., non-dynamic) simulations, the authors found that the approach to coordinated control of hexapedal locomotion...
In this paper we present the design of a swallowable (11mm diameter by 25mm long), 12-legged endoscopic capsule for locomotion in the lower gastro intestinal tract (large bowel). A novel slot-follower mechanism driven via lead-screw allows the capsule to be as small as current commercial pill-cameras, while simultaneously generating 2/3 N of force at each leg tip. Kinematic and static analyses of...
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