A novel approach to obstacle detection using optical flow without recovering range information has been developed. This method can be used for ground vehicles to navigate through man-made roadways or natural outdoor t...
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A novel approach to obstacle detection using optical flow without recovering range information has been developed. This method can be used for ground vehicles to navigate through man-made roadways or natural outdoor terrain or for air vehicles to land on known or unknown terrain. A linear relationship, plotted as a line and called a reference flow line, has been found. This reference flow line can be used to detect discrete obstacles above or below the reference terrain. Slopes of surface regions are also computed. The approach is simple, fast, and robust because: (1) the only required information is one component of the optical flow, (2) each image line can be processed in parallel, and (3) the error sources involved are reduced to a minimum. An initial experiment using noisy synthetic data is also included to demonstrate the applicability and robustness of the method.< >
A method for the path-control of automated guided vehicles (AGVs) in computer integrated manufacturing (CIM) systems that combines the flexibility and easy installation of optical methods with the simplicity and robus...
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A method for the path-control of automated guided vehicles (AGVs) in computer integrated manufacturing (CIM) systems that combines the flexibility and easy installation of optical methods with the simplicity and robustness of the inductive method is proposed. Using a new computing paradigm, the cellular neural network (CNN), and a related device, the VLSI CNN chip, a very high speed solution that is less expensive than the conventional methods can be achieved. This AGV control complies with the requirements of CIM systems. Further advantages of the proposed system are as follows: fault tolerance and the ability to give instructions along the path, and the use of a simple local control.< >
In this paper, an approach to modelling of a robotic assembly cell is proposed and a method for managing the cell operation is described using a knowledge base. Since the modelling structure is based on the concept of...
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In this paper, an approach to modelling of a robotic assembly cell is proposed and a method for managing the cell operation is described using a knowledge base. Since the modelling structure is based on the concept of the state variable, the relationships between states are described by the state transition map (STM). The knowledge-bases for state transition and assembly job information are obtained from the STM and the assembly job tree (AJT), respectively. Using the knowledge-base, the system structure is discussed in relation to both managing the cell operation and evaluating the performances. Finally, a simulation algorithm is presented with the simulation results to show the significance of the proposed modelling approach.
This survey discusses current approaches to the robust control of the motion of rigid robots and summarizes the available literature on the subject. The five major designs discussed are the “Linear-Multivariable” ap...
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Specification and verification of system integration are the central issues in the design, implementation, and operation of Computer-Integrated Manufacturing systems. This paper shows that both specification and verif...
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Specification and verification of system integration are the central issues in the design, implementation, and operation of Computer-Integrated Manufacturing systems. This paper shows that both specification and verification can be addressed conveniently and effectively by using Petri nets. The primary goals here are to develop a Petri net model for the integration specification of a CIM system for part processing, to conduct process analysis for the system based on its Petri net model for the purpose of verification, and finally, to determine some supervisory control procedures, such as deadlock prevention and avoidance, for the system according to the result of analysis and the other specified requirements.
This work explores a method for path planning for a robot in an environment that consists of stationary and moving obstacles. The technique uses binary partitioning of the environment by the obstacles to establish and...
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This work explores a method for path planning for a robot in an environment that consists of stationary and moving obstacles. The technique uses binary partitioning of the environment by the obstacles to establish and analyze the spatial relationship between robot and obstacles. Hyperplanes are used to obtain recursively a disjoint set of D-dimensional cells, with each cell designated as belonging to either the interior or the exterior of the set. An overt idea of binary space partitioning as a representation of polytopes is given. Thus, the space-time configuration of free space is viewed as disjoint polytopes; each point in space-time is considered a map into a unique polytope. A traversal of the tree is used to obtain a linear order which gives the collision probability with the environment. Adjacent polytopes between the start and goal polytopes are then utilized to obtain a trajectory. Current implementation for a 2D static environment is discussed.< >
Dynamic segmentation is a method for improving the performance of cooperating tasks executed on loosely coupled multiprocessors. Four different data transfer techniques that can be used for intersegment data transfers...
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Dynamic segmentation is a method for improving the performance of cooperating tasks executed on loosely coupled multiprocessors. Four different data transfer techniques that can be used for intersegment data transfers in dynamically segmented buses are analyzed. Preemptive data transfers are considered for uniform message latencies and results are provided for message latency comparisons using various locality factors. These results indicate dynamic segmentation improves performance considerably, at a fraction of the cost of more complex interconnection networks such as multiple buses.< >
A novel method for solving the motion planning problem in the presence of moving obstacles is presented. Compared to previous approaches, the proposed method is more general in that obstacles are allowed to move with ...
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A novel method for solving the motion planning problem in the presence of moving obstacles is presented. Compared to previous approaches, the proposed method is more general in that obstacles are allowed to move with translation and rotation at nonlinear velocity. Using path/velocity decomposition, the method emphasizes the development of an efficient algorithm for collision detection between the robot and moving polygons. This algorithm is devised using transversability vector theory to determine the geometric relationships between any two convex polygons or convex components of concave polygons. The interference between the robot and the moving obstacles is detected and registered on the constraint map to represent time constraints on the robot's motion along the path. The constraint map is then used for velocity planning using a simple algorithm. The problem of a robot crossing the street is used as an example for computational analysis.< >
A parallel-jaw type multiple-d.o.f. robot hand is designed and implemented to manipulate workpieces within the hand by rotation and translation. An efficient manipulator control algorithm and part mating application i...
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A parallel-jaw type multiple-d.o.f. robot hand is designed and implemented to manipulate workpieces within the hand by rotation and translation. An efficient manipulator control algorithm and part mating application is developed. A simulation result is also presented to show the changes of force during part insertion to verify the models developed.< >
A new approach to solving the collision detection problem for mobile robots in the presence of moving obstacles is proposed. Both the robot and obstacles in the two-dimensional space are assumed to be polygonal and ar...
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A new approach to solving the collision detection problem for mobile robots in the presence of moving obstacles is proposed. Both the robot and obstacles in the two-dimensional space are assumed to be polygonal and are composed of a set of convex polygons. The half-plane representation uses an algebraic method to describe the object motion including translation and rotation through time. Compared with previous methods, the proposed representation is more general in that obstacles are now allowed to move at nonconstant velocities. To detect collision between polygonal objects, a traversability vector method was developed. Traversability vectors are a simple mechanism used to analyze geometric constraints imposed by polygons. Using these vectors, a simple algorithm for predicting collision is derived. Computer simulations were conducted to show the feasibility of the proposed method.< >
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