Petr Wagner

Path planning and tracking for robots based on cubic hermite splines in real-time

This paper deals with path planning using cubic Hermite splines in real-time control of wheeled robots. The first part describes the filtering and prediction of the robot position. The discrete form of the extended Kalman filter is introduced on the basis of the robot model. The second part shows a computation of trajectories based on Hermite splines. The details of recomputation of the trajectory in each system cycle are mentioned. The velocity profile of the computed trajectory is then determined in order to achieve smooth movement within given physical constraints. A Feedback and feedforward controller is used to control the motion on the calculated trajectory. The paper concludes with a comparison of the trajectory computed by simulation and the trajectory measured on the real robot.

Constrained optimization of robot trajectory and obstacle avoidance

This paper deals with time-optimization of trajectories of wheeled robots within the speed and other constraints. The cubic Hermite spline curve with the method of speed profile computation is used to determine the trajectory. This method is summarized and extended to allow the optimization with the described constraints. It ensures fulfilment of required initial parameters of motion. The parameters of motion and trajectory are described using a model with stationary obstacles. Then algorithm of optimization is developed and tested by means of a hypothetical example. The results are computed by nonlinear solver in MATLAB. A neural network is then introduced to accelerate the calculation of the numerically computed optimal results. The trained network is compared with numerical solution.

Motion control for robots based on cubic Hermite splines in real-time

Abstract This paper deals with the path planning and path tracking using the cubic Hermite splines in real-time control of wheeled robots. The first part describes problems of motion control in real-time. The second part shows a computation of trajectories based on Hermite splines. The details of recomputation of the trajectory in each system cycle are also covered. The velocity profile of the computed trajectory is then determined in order to achieve smooth movement within given physical constraints and minimum driving time. Feedback and feedforward controllers are used to control the motion on the calculated trajectory. The paper concludes with experimental results of the presented solution of robot control. The results of the proposed method after online trajectory adjustment and recomputation are presented.

Wireless transceiver for control of mobile embedded devices

This article deals with the control of mobile embedded devices via wireless transceiver. The only way how to control the mobile devices such as robots, is to use a wireless data transfer. The possible wireless transceiver solution using the nRF24L01 transceiver by Nordic Semiconductor, which works in license-free worldwide 2.4 GHz ISM frequency band, is presented. Overview of this chip is included at the beginning of this article. The main part of this article deals with the design of a communication protocol. Then some optimizations of this protocol to improve its performance and determinism are discussed. In the last part, the results of measurement of some data transfer characteristics are presented.

Machine vision for robot-soccer application

Abstract This paper presents the computer image processing system for robot-soccer application. It presents and explains the main parts of robot-soccer image processing: image format conversion, pitch filtering, recognition of ball, recognition of color segments, and matching groups of segments with the robots. It also explains the main principles of image processing optimization: image data reduction, code optimization, and multi-core processors utilization.

Dynamic Optimization Case Studies in Matlab&Simulink and Dynopt

The paper deals with the case studies concerning the problems of dynamic optimization. It introduces the following examples: problem with free time and fixed end point, problem with fixed time and free end point, and problem with fixed time and fixed end point. It shows the construction of the models in Matlab&Simulink and Dynopt toolbox, and their solution and verification of the results.

Design and simulation of the embedded system

Abstract This paper is focused on the design, modelling, and simulation of an embedded systems using UML. UML is de facto the standard for modelling of software systems. However, UML should be extended to allow the modelling of real-time and embedded systems. The UML profile MARTE (Modelling and Analysis of Real Time and Embedded systems) was developed by consortium OMG to address the modelling of this kind of systems where time and allocation of both hardware and software resources are very important metrics of the system. The MARTE profile allows the modelling the system using different views on this system. The automatic source code generation and simulations are mentioned in connection with MARTE. There is presented the first proposal of a new simulation and verification tool which is being developed at our university.

Optimization of Robot Trajectory with Motion Constraints

Abstract This paper deals with time-optimization of trajectories of wheeled robots within the speed and other constraints. The cubic Hermite spline curve with method of speed profile computation is used to determine the trajectory. This method is extended to allow the optimization with the constraints described. It ensures fulfillment of required initial parameters of motion. There is analyzed both situation without obstacle and with single stationary obstacle. Neural network is then introduced to accelerate the calculation of numerically computed optimal results.