380 research outputs found
Ground Target Tracking with Multi-Lane Constraint
Knowledge of the lane that a target is located in is of particular interest in on-road surveillance and target tracking systems. We formulate the problem and propose two approaches for on-road target estimation with lane tracking. The first approach for lane tracking is lane identification based ona Hidden Markov Model (HMM) framework. Two identifiers are developed according to different optimality goals of identification, i.e., the optimality for the whole lane sequence and the optimality of the current lane where the target is given the whole observation sequence. The second approach is on-road target tracking with lane estimation. We propose a 2D road representation which additionally allows to model the lateral motion of the target. For fusion of the radar and image sensor based measurement data we develop three, IMM-based, estimators that use different fusion schemes: centralized, distributed, and sequential. Simulation results show that the proposed two methods have new capabilities and achieve improved estimation accuracy for on-road target tracking
Control Software of Robot Compliant Wrist System
The compliant wrist combining passive compliants and sensor has been developed in GRASP laboratory. The device provides the robot system the necessary flexibility which accommodates transitions as the robot makes contact with the environment, corrects positioning error in automatic assembly, avoids high impact forces and protects the surface from damage. The device also supplies the displacement sensing of the passive compliance so that active feedback control is possible.
This report is intended to serve as a reference material to introduce the control software of the robot compliant wrist system developed and implemented in the lab. The detail discussion on system performance and parameters selection can be found in the thesis [3].
The rest of material is organized as follows.
Section 2 introduces the compliance control methods of robot manipulators. The historic development of both passive and active compliance method is discussed. The advantages and disadvantages of the methods are investigated. Based on the unsolved problems in this issue, the six-degree freedom compliant wrist is developed, and the design feature is presented.
Section 3 discusses the hybrid position/force control scheme using the sensing information from the device. The positioning error due to load or external force when robot moves in free space is compensated for, so that the effective stiffness is increased. In force control when robot is constrained by environment, the trajectory is modified by sensed force, so that the effective stiffness is decreased.
Section 4 deals with the implementation of the control scheme. Various programs have been developed to perform the hybrid control operations, such as hybrid control demonstration, surface tracking, edge tracking, insertion and pulling out, and writing operation. The programs have been successfully implemented in the experiments. Definition and selection of the parameters in the programs are discussed.
Section 5. is the source code of control scheme which has been implemented in PUMA 560 with index machine in GRASP Laboratory. The control is executed on a MicroVax I1 using the RCI primitives of RCCL
Wet-processing of low-protein hard winter wheat flour to improve its breadmaking potential
Call number: LD2668 .T4 1985 W8Master of Scienc
Ground Target Tracking with Multi-Lane Constraint
Knowledge of the lane that a target is located in is of particular interest in on-road surveillance and target tracking systems. We formulate the problem and propose two approaches for on-road target estimation with lane tracking. The first approach for lane tracking is lane identification based ona Hidden Markov Model (HMM) framework. Two identifiers are developed according to different optimality goals of identification, i.e., the optimality for the whole lane sequence and the optimality of the current lane where the target is given the whole observation sequence. The second approach is on-road target tracking with lane estimation. We propose a 2D road representation which additionally allows to model the lateral motion of the target. For fusion of the radar and image sensor based measurement data we develop three, IMM-based, estimators that use different fusion schemes: centralized, distributed, and sequential. Simulation results show that the proposed two methods have new capabilities and achieve improved estimation accuracy for on-road target tracking
Analysis and experiments on flow-induced hemolysis.
Hemolysis (red cells lysis) caused by fluid stresses in flows within hypodermic needles, blood pumps, artificial hearts and other cardiovascular devices, is one of the major concerns during the design and use of cardiovascular or blood-processing extracorporeal devices. A non-invasive experimental method which does not interfere directly with red blood cells was designed to investigate the red cells\u27 deformations in response to a range of flow conditions. The designed flow chamber and pump system provided a controlled two-dimensional Poiseuille flow with average velocity of up to 4 m/s and a range of fluid stresses up to 5000 dyn/cm 2 . The dimension of deformed cells and positions was measured to obtain the aspect ratio of red cells under stress from images captured by the microscope-laser-camera system. A strain-based blood damage model from Rand\u27s viscoelastic model was built to predict cell strain. The empirical coefficients in the blood damage model were calibrated by the measurements from the experiments. Flow-induced hemolysis in the blood flow through hypodermic needles was investigated. The flow-induced hemolysis of the needles may be reduced by a modified design of the entrance geometry of the needle. Three groups of 16 gauge needles were compared: one standard group with sharp entrance, another with beveled entrance and a third with rounded entrance. The CFD analysis combined with the strain-based blood damage model, Heuser et al. model and Giersiepen et al. model respectively was used to analyze the flow-induced hemolysis of the three needles. The predicted results were compared to the experimental results, which showed the rounded entrance reduced hemolysis by 34%, but the beveled entrance increased hemolysis by 38%. The strain-based blood damage model predicted the reduced hemolysis by 7.4% in rounded needle and the increased hemolysis by 13% in beveled needle. Both Heuser et al. model and Giersiepen et al. model predicted increased hemolysis in rounded needle
Gyroscopically Stabilized Robot: Balance and Tracking
The single wheel, gyroscopically stabilized robot - Gyrover, is a dynamically
stable but statically unstable, underactuated system. In this paper, based on
the dynamic model of the robot, we investigate two classes of nonholonomic
constraints associated with the system. Then, based on the backstepping
technology, we propose a control law for balance control of Gyrover. Next,
through transferring the systems states from Cartesian coordinate to polar
coordinate, control laws for point-to-point control and line tracking in
Cartesian space are provided
Does Early-Bird Policy Matter for Equity Crowdfunding Performance: The Moderation Roles of Entrepreneur Gender and Project Types
Dynamic Balance Control of Multi-arm Free-Floating Space Robots
This paper investigates the problem of the dynamic balance control of
multi-arm free-floating space robot during capturing an active object in close
proximity. The position and orientation of space base will be affected during
the operation of space manipulator because of the dynamics coupling between the
manipulator and space base. This dynamics coupling is unique characteristics of
space robot system. Such a disturbance will produce a serious impact between
the manipulator hand and the object. To ensure reliable and precise operation,
we propose to develop a space robot system consisting of two arms, with one arm
(mission arm) for accomplishing the capture mission, and the other one (balance
arm) compensating for the disturbance of the base. We present the coordinated
control concept for balance of the attitude of the base using the balance arm.
The mission arm can move along the given trajectory to approach and capture the
target with no considering the disturbance from the coupling of the base. We
establish a relationship between the motion of two arm that can realize the
zeros reaction to the base. The simulation studies verified the validity and
efficiency of the proposed control method
The Status and Progress of Resource Utilization Technology of e-waste Pollution in China
AbstractIn this paper, the current status and the characteristics of e-waste were presented. The hazards of electronic wastes, significance of their recycle, resource utilization technology at home and aboard are summarized in this paper. Several recycling methods were introduced such as recycling of metals, plastics and glass, etc. The way of comprehensive utilization to e-waste in China was pointed out
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