Alexandre Poty

Consideration of obstacle danger level in path planning using A* and fast-marching optimisation: comparative study

Obstacle danger level is taken into consideration in path planning using fractional potential maps. This paper describes the two optimisation methods tested: the A* algorithm and the Fast-Marching technique. The efficiency of the two approaches is illustrated and compared through a vehicle path planning application in a fixed obstacle environment. A* is a heuristically ordered research algorithm and is complete and admissible. Fast-Marching provides a convex map without local minima and permits real-time evaluation of optimal trajectories. A vehicle path planning application is considered in a fixed obstacle environment. A specific danger level is given to each obstacle. The obtained continuous curve trajectories are compared.

Flatness Control of a Fractional Thermal System

This paper concerns the application of flatness principle to fractional systems. In path planning, the flatness concept is used when the trajectory is fixed (in space and in time), to determine the controls inputs to apply without having to integrate any differential equations. A lot of developments have systems), few developments are still to be made. So, the aim of this paper is to apply flatness principle to a fractional system. As soon as the path has been obtained by flatness, a new robust path tracking based on CRONE control is reminded. The fractional systems dynamic inversion is studied. A robust path tracking based on CRONE control is presented. Finally, simulations on a thermal testing bench model, with two different controllers (PID and CRONE), illustrate the path tracking robustness.

Attractive Force Based on Fractional Potential in Dynamic Motion Planning for Mobile Robot

In path planning, potential fields introduce force constraints to ensure curvature continuity of trajectories and thus to facilitate path-tracking design. In previous work, a path planning design by fractional (or generalized) repulsive potential has been developed to avoid fixed obstacles. A fractional road was determined by taking into account danger of each obstacle. Danger level of each obstacle is characterized by the fractional order of differentiation. Then a new attractive force based on fractional potential was introduced, with the aim to extend the method to dynamic obstacles characterized by fractional potential fields. In this paper a comparison between each classical attractive force is presented. Then the new attractive force based on fractional potential is introduced. Finally, this attractive force is applied on an example and compare with the Ge and Cui method which is the classical potential fields for motion planning of mobile robots in a dynamic environment.Copyright

FREQUENCY BAND-LIMITED FRACTIONAL DIFFERENTIATOR IN PATH TRACKING DESIGN

Abstract A new approach to path tracking using fractional differentiation is proposed in this paper. It is an extension of a previous method considering a Davidson-Cole transfer function as I/O transfer function. A methodology for synthesized a prefilter is defined using I/O Frequency Band-Limited Fractional Differentiator (FBLFD) transfer function whose two main properties are having no overshoot on the plant output and by adding numerator to have maximum control value for short time. These properties are available whatever the values of its constitutive parameters. This permits synthesis from only three parameters. The optimum settling time of the I/O transfer function is thus obtained. Transfer function synthesis requires the maximum value of the control signal by taking into account a frequential constraint. The prefilter can be implanted in the same way as a classical digital filter.

PRESHAPING COMMAND INPUTS FOR 2ND GENERATION CRONE CONTROL: APPLICATION ON AN INSTRUMENTED DC MOTOR BENCH

Shaping command input or preshaping is used for reducing system oscillation in motion control. Desired systems inputs are altered so that the system finishes the requested move without residual oscillation. This technique, developed by N.C. Singer and W.P. Seering, is used for example in the aerospace field, in particular in flexible structure control. This paper presents the study of ZV shaper for explicit fractional derivative systems (generalized derivative systems). A robustness study of ZV shaper is then presented and applied to improve second generation CRONE control response time. Results in simulation and on a DC motor bench are given.Copyright