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The reaction wheel stabilizer (RWS) concept for bipedal stabilization consists of a wheel that can be accelerated in order to impart a reaction torque on the rest of the biped. The beneficial effects of such a device (or emulation of such a device through limb motion) on transient body motions are not well understood. This work quantifies this phenomenon by comparing optimal trajectories for robots...
To enable robust dynamic walking on the Atlas robot, we extend our previous work by adding a receding-horizon component. The new controller consists of three hierarchies: a center of mass (CoM) trajectory planner that follows a sequence of desired foot steps, a receding-horizon controller that optimizes the next foot placement to minimize future CoM tracking errors, and an inverse dynamics based full...
For real-time feedback and cost-efficient analysis from sport videos, it is essential to automatically identify players. In this paper, we propose a method for identifying sport players in videos. Our method uses wearable sensors to obtain their motions. Player identification is achieved by motion feature matching between (unknown) players in videos and wearable sensors whose IDs are already known...
Videos from an Unmanned Aerial Vehicle (UAV) platform have become more available in the surveillance community. As the number of video samples are increasing, automated analysis of these videos have become important. In this paper, we describe the task of vehicle movement event classification in videos taken from UAV. Given object track information from UAV video sequences, we processed the noisy...
This paper concerns on an optimal control problem of a robot movement from an initial point to another target point while avoiding obstacles. Previous study had generated a trajectory that should be taken by the robot to minimized the consumed energy while moving with constant velocity. Here, we find the optimal performance index value which minimizes the trajectory length as well as the energy usage...
We report an automated method for teleoperation of unmanned ground vehicles in complicated environments using multi-channel LiDAR and a video camera. To improve accurate remote control and compensate signal transmission latency, a method for trajectory prediction based on dynamic model is proposed. Unlike earlier 2D trajectory prediction, our method utilizes LiDAR point data to generate 3D trajectory...
Aiming at the trajectory prediction in forecast handover process of early warning detection system, a method of prediction trajectory for unpowered gliding hypersonic vehicle in the gliding phase is proposed. Firstly, the motion characteristic of the unpowered glide hypersonic vehicle in gliding phase is analyzed to verify the feasibility of using a polynomial model to predict the target trajectory...
This report presents the results of the development of method of forming of motion laws for mechatronics objects (MO) along trajectories with the desired speed. Desired trajectories are described by third order parametric splines. Analytical expressions describing the dependence of the rate of change of the parameter from the laws of change of given speed and information about the parametric form...
In many fields of MRI (Magnetic Resonance Imaging), especially in DMRI (Dynamic MRI) domain, long acquisition time often limits its clinical applications. The new online MRI technique can obviously accelerate the imaging time for DMRI based on under-sampling acquisition and sparsity performance between neighbor frames. The data acquisition of previous online MRI schemes was based on the Cartesian...
This paper presents an on-line estimator to evaluate the inertia-related parameters for a class of quasi-linear mechanical systems. The proposed estimator is established on the designed virtual acceleration error signal, and only the measurements for velocity and position are needed, therefore the usage of an accelerometer is avoided. The performance of the proposed estimator is verified on the numerical...
We present a framework for online coordinated obstacle avoidance with formal safety guarantees. Such a formally verified trajectory planner can be used in shared human-robot workspaces to guarantee safety. The obstacle avoidance is based on estimation of the human occupancy on two different time scales. A long-term plan is created based on a probabilistic task representation, learned by demonstration,...
An engagement dynamic model is set up for the miniature missile guidance solution under the constraints of field-of-view angle and terminal impact angle. The impact-angle constraint guidance law design is converted into an optimal control problem subjected to terminal constraints. Then a look angle guidance solution without line-of-sight rate is detailed to satisfy the requirement on field-of-view...
Path tracking, as a subproblem in trajectory planning, is one of the most significant topics in robot researches. In this paper, a time-optimal trajectory planner is proposed, which tracks the specified B-spline path with limit jerk. This planner utilizes the master-slave strategy to plan trajectory for all axes. In the preprocessing stage, switching points are divided into two types: critical points...
Terahertz (THz) streaking at individual sharp metallic tips allows for the control of photoelectron pulses in nanoscale volumes. The time-varying acceleration in the enhanced THz near-field facilitates a reshaping of electron energy spectra, corresponding to a manipulation of the phase space distribution. Here, we discuss our recent experimental and theoretical work on THz near-field streaking, with...
Fast motions of systems with constrained flexible dynamics often lead to residual vibrations. Established methods for compensating those vibrations such as input-shaping, filtering and feed-forward methods are already available. However, those methods do not explicitly consider input-constraints. As a consequence, they cannot effectively reduce residual vibrations if input-constraints are violated...
Interception of target that is performing a three dimensional barrel roll maneuver-helix trajectory is dealt with. The existing approaches are dealing with the guidance in three dimensional coordinates frame as three separated-independent problems. This representation of the trajectory assumes no coupling between the axes. However the equations of motion in the three axes of a barrel roll maneuver-helix...
Much research has been done on the subject of collision avoidance (COLAV). However, few results are presented that consider vehicles with second-order nonholonomic constraints, such as autonomous underwater vehicles (AUVs). This paper considers the dynamic window (DW) algorithm for reactive horizontal COLAV for AUVs, and uses the HUGIN 1000 AUV in a case study. The DW algorithm is originally developed...
In this paper, we propose a central coordination system to compute optimized trajectories of intelligent vehicles in a double lane road with traffic lights. The focus is to decrease travel time when comparing to human drivers traffic. First, we predict the waiting line formation order when vehicles approach traffic lights. Then, we compute a global motion plan in order to force trajectories result...
In this paper a method is presented that allows an operator to hand-guide a robot along a predefined geometric path. This is a common use case in robot assisted surgery, which often has high demands on precision. In order to ensure the path accuracy of the robot, joint velocity and joint acceleration constraints are enforced to prevent undesired saturation effects of the actuators. Furthermore, necessary...
This paper aims to develop a modeling framework for optimizing the timing of a set of traffic signals by considering individual vehicle characteristics (such as fuel consumption and travel time). Through the Vehicle to Infrastructure (V2I) communications, such individual vehicle information is available for the infrastructure center to produce optimal signal timing. The proposed strategy applies the...
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