Maki K. Habib

Invited paper. Boolean matrix representation for the conversion of minterms to Reed–Muller coefficients and the minimization of Exclusive-OR switching functions

Two new efficient algorithms are proposed to convert the minterms of a switching function to the coefficients of its Reed-Muller polynomial with fixed polarities. The conversion procedure is based on the use of boolean matrix representation. The first algorithm is applied to generate all the generalized Reed-Muller expansions of the related switching function and select the optimum solution from them. The second algorithm is applied to generate directly the minimal generalized Reed-Muller expansion for a given switching function without undertaking all possible fixed polarity realizations. The two algorithms can also be applied to generate the minimal Exclusive-OR realization in fixed polarity for the incompletely specified functions. Two fast and efficient computer simulations for the proposed algorithms have been developed using BASIC programming language, these computer programs accept the number of the function variables and the minterms of a switching function and return the minimal Reed-Muller expan...

Map representation of a large in-door environment with path planning and navigation abilities for an autonomous mobile robot with its implementation on a real robot

Abstract In this research a complete development and implementation of a navigation system for an in-door autonomous mobile robot is presented. The constitution of the developed navigation system consists of: (1) An efficient hierarchical map representation method to model a large in-door environment. This method describes the significant features of an actual in-door world consisting of either a single building or a network of buildings connected through common bridges (a corridor like pass way), in which the robots environment is divided hierarchically using a tree structure into three levels, Building, Corridor and Room. (2) A prior preparation algorithm to prepare the information necessary for path planning using the robots environment model for the purpose to have fast and efficient path planning algorithms. (3) Fast and computationally efficient automated path planning strategy that generates collision free paths made of straight lines. This strategy includes two algorithms, (a) hierarchical planning for Building and Corridor levels, and (b) free space planning for a Room level. Consequently, geometrical and scene information along a generated path is abstracted to support real time actions while navigating the path. (4) A real time navigation algorithm to ensure real time control of robots behavior, and to monitor the actual execution of the planned path in a real environment. For the purpose of having a reliable navigation system, a new real time language based on the Action Mode concept as a unit of robots motion representation is developed. Using this language the sensor based mobile robots behavior can be described. The developed navigation system is implemented and demonstrated on an actual mobile robot called Yamabico. M in a real in-door environment. The demonstration results show the effectiveness of the implemented navigation system with its proposed constitution.

Structuring free space as prime rectangular areas (PRAs) with on-line path planning and navigation for mobile robots

A method is presented for modeling a robot environment and structuring its free space in terms of a set of overlapped prime rectangular areas (PRAs) which are suited for path planning and navigation tasks. Next, a connectivity table for the overlapped PRAs is constructed to provide the structure necessary for path-finding. Using the generated overlapped PRAs, a simple and computationally effective online path planning algorithm is proposed to generate the optimal collision-free path in terms of intersected PRAs from the PRA containing a start point to a PRA containing a goal point within the robots environment. Since the movements between the PRAs cannot have fixed cost distance attached to them, an efficient technique that dynamically allocates cost to path segments as the path develops is proposed. A real-time execution algorithm is developed to control the robot during the execution of the planned path. Experimental examples based on the proposed algorithms with its results are presented for selected environments executed on the mobile robot Yamabico.M (Level-12).<<ETX>>

Efficient on-line path planning algorithm and navigation for a mobile robot

A simple and efficient method for modelling a robot environment and an efficient on-line path planning algorithm are proposed to generate the optimal path within that environment. The suggested path planning algorithm is based on a good method for structuring the free space of a mobile robot environment into a set of overlapping prime rectangular areas PRAs that are suited to path planning and navigation tasks. The structuring of the free space environment starts by dividing the enlarged world map of that mobile robot environment into rectangular cells. These cells represent free and closed areas. Then, the free space in the specified environment is structured in terms of PRAs, and a connectivity table is constructed to provide the structure necessary for path finding. Using these results, a simple and computationally efficient algorithm is described which solves the pathfinding from a PRA containing the starting point to a PRA containing the goal point. Since movement between the PRAs cannot have fixed c...

Development and implementation of navigation system for an autonomous mobile robot working in a building environment with its real time application

An intelligent navigation system for a autonomous mobile robot using hierarchical world map representation has been developed and implemented. This navigation system can successfully negotiate a robots environment consisting of a network of buildings connected through common bridges. The experimental results and analysis of the implemented navigation system in a real environment are described. The developed navigation system comprises: (1) world model construction with three levels of hierarchy (building, corridor, and room); (2) two efficient techniques to plan a collision-free path to a specified goal within a known environment (in-room planning and corridor and building planning); and (3) control of the robot while executing the chosen path after abstracting the geometrical information along it from the related world model. The proposed navigation system has been demonstrated for application in a real environment that consists of a network of buildings. A real mobile robot, Yamabico.M (Level-12) that has been developed by the authors was used.<<ETX>>

New approach for the generation of minimal Reed-Muller Exclusive-OR expansions with mixed polarity

Abstract A new, simple and computationally effective algorithm attempted to obtain the minimal Reed-Muller Exclusive-OR expansion with mixed polarity of a given switching function, i.e. each product term may contain variables in complemented and uncomplemented forms. The major consideration of this algorithm is to obtain a minimum number of product terms in the Exclusive-OR function. The suggested method is based on the use of boolean matrix representation, and it is suitable for completely and incompletely specified functions, large variable functions and for computer and manual simulation. This paper also describes the computer simulation of the introduced algorithm, which helps in the detection of the final decomposition of the given function. Such realizations are described using both manual and computer simulations.

Brief communication, Digital control loop based on a microprocessor for optimal gain tuning

This paper investigates the hardware implementation of a digital control loop based on a microprocessor for optimal gain tuning. It consists of a digital controller implemented on an 8085 microprocessor and an analogue plant simulation (implemented on an analogue computer). Automatic adjustment of a time-variant gain controller is carried out to improve the dynamic performance of the closed-loop system response. The optimum tuning for the gain contoller is solved analytically using the Phillips integral algorithm in the sense of minimizing the integral-squared error (ISE) criterion formulated in the time domain. An example of a third-order servomechanism control system is considered to show the usefulness and efficiency of this technique in improving the transient response of the closed-loop control system. A comparison is made between the theoretical system response (obtained using an off-line computation procedure) and the real-time implementation of the control problem.