Application of fusion 2D lidar and binocular vision in robot locating obstacles

If robot uses 2D lidar or binocular camera to locate obstacles, there will be some problems such as missing obstacle information or inaccurate obstacle locating, which will affect the normal work of the robot. In order to obtain accurate 3D obstacle information, this paper proposes an algorithm for fusing 2D lidar and binocular vision to complete the obstacle location. In this paper, the depth value of the 2D lidar point cloud is used as a benchmark. By fitting the error equation of the binocular camera point cloud depth value, the depth value of the camera point cloud is modified to obtain an accurate 3D camera point cloud, thereby obtaining an accurate 3D obstacle information. Many experiments have proved that the fusion algorithm of 2D lidar and binocular vision can obtain accurate 3D obstacle information. The method of fusion 2D lidar and binocular vision can approximately achieve the measurement effect of 3D lidar, and the point cloud of obstacles is relatively dense, so the accurate 3D obstacle information can be obtained. This method can reduce the influence of single sensor on the robot locating obstacles, thus completing the accurate locating of obstacles, which is of certain significance to robot navigation.

Using Microthermostatting to Increase Thermal Stability of On-Board Electronics

The paper considers a promising temperature control method for electronic equipment, that is, microthermostatting, which is characterised by maintaining a stable temperature in specific electric and radio devices. We show that the temperature error equation may be the most universal mathematical model for developing microthermostatted electronics. Statistical analysis methods concerning operation modes of an electronic circuit used in a device make it possible to obtain a regression model that forms the basis for deriving the temperature error equation. We propose to replace a physical factorial experiment with a numerical factorial experiment in order to reduce the time spent performing the statistical analysis. We note that it may be possible to implement this numerical factorial experiment using well-known circuit simulation software packages. The general form of the temperature error equation enables us to conclude that in the process of investigating the thermal stability of an electronic device there arise three subproblems: 1) the problem of synthesising fitting mathematical models for the electric and radio equipment; 2) the circuit modelling problem regarding the circuit used; 3) the topology design problem for computing the temperature field. In the experimental part of our investigation, we propose a simple design for a heater microthermostat in a voltage regulator. A feature of the microthermostat design is a microcontroller to form corrective actions affecting the actuators. In our studies we compared two voltage regulator designs: 1) without thermostatting; 2) using microthermostatting. We show that the thermostatted option displays thermal stability that is 2.68 times higher than that of the basic option

Trajectory tracking sliding mode control for underactuated autonomous underwater vehicles with time delays

Trajectory tracking control of autonomous underwater vehicles in three-dimension always suffers disturbances such as input time delays and model uncertainties. Regarding this problem, an integral time-delay sliding mode control law is proposed in this article with dividing the vehicle’s input time delays model into cascade system consisting of a kinematics subsystem and a dynamics subsystem. Based on the established pose error equation and velocity error equation, a suitable Lyapunov–Krasovskii functional is given to analyze and guarantee the global stability of the whole system under reasonable assumptions. At last, comparative simulations are presented to demonstrate the effectiveness of the proposed method.

An Improved ACKF/KF Initial Alignment Method for Odometer-Aided Strapdown Inertial Navigation System

For a land-vehicle strapdown inertial navigation system (SINS), the problem of initial alignment with large misalignment angle in-motion needs to be solved urgently. This paper proposes an improved ACKF/KF initial alignment method for SINS aided by odometer. The SINS error equation with large misalignment angle is established first in the form of an Euler angle. The odometer/gyroscope dead reckoning (DR) error equation is deduced, which makes the observation equation linear when the position is taken as the observation of the Kalman filter. Then, based on the cubature Kalman filter, the Sage-Husa adaptive filter and the characteristics of the observation equation, an improved ACKF/KF method is proposed, which can accomplish initial alignment well in the case of unknown measurement noise. Computer simulation results show that the performance of the proposed ACKF/KF algorithm is superior to EKF, CKF and AEKF method in accuracy and stability, and the vehicle test validates its advantages.

Corrigendum: In the paper Contribution study of the thermodynamics properties of the ammonia-water mixtures, doi reference: 10.2298/TSCI110206083K

Simeon Oka, Editor-in-Chief of the journal Thermal Science request that it is necessary to correct Equation No. 6 in the paper CONTRIBUTION STUDY OF THE THERMODYNAMICS PROPERTIES OF THE AMMONIA-WATER MIXTURES by Sahraoui KHERRIS a, b*, Mohammed MAKHLOUF b, Djallel ZEBBAR a, and Omar SEBBANE c aInstitute of Sciences and Technology, University of Tissemsilt, Tissemilt, Sidi Bel Abbes, Algeria bReactifs Systems and Materials Laboratory, Djillali LIABES University, Algeria cMaterials and Renewable Energy Laboratory, Abou Bekr Belkaid University, Tlemcen, Algeria Original scientific paper DOI: 10.2298/TSCI110206083K published in the journal THERMAL SCIENCE: Year 2013, Vol. 17, No. 3, pp. 891-902 since due to typing error Equation No. 6, of this paper has not been correctly written.<br><br><font color="red"><b> Link to the corrected article <u><a href="http://dx.doi.org/10.2298/TSCI110206083K">10.2298/TSCI110206083K</a></b></u>

A Sort of New Improved Algorithm For Total Least Square

Aim to blemish of total least square algorithm based on error equation of virtual observation, this paper put forward and deduced a sort of new improved algorithm which selects essential unknown parameters among designing matrix, and then, doesn’t consider condition equation of unknown parameters among designing matrix. So, this paper perfected and enriched algorithm, and sometimes, new method of this paper is better. Finally, the results of examples showed that new mothod is viable and valid.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

Improved Total Least Square Algorithm

Aim to blemish of total least square algorithm based on error equation of virtual observation,this paper proposed a sort of improved algorithm which doesn’t neglect condition equation of virtual observation,and considers both error equation and condition equation of virtual observation.So,the improved algorithm is better.Finally,this paper has fitted a straight line in three-dimensional space based on the improved algorithm.The result showed that the improved algorithm is viable and valid.

Geometric and Motion Error Model and Precision Analysis of Multiaxial EDM

The precision of Multiaxial EDM is improved by a geometric and motion error model of EDM. A lower numbered body array is introduced to describe the EDM with a homogeneous coordinate transformation used to model the geometric and motion errors of a typical body in the multi-body system. Multi-body kinematics are employed to derive the structural and motion relations and the corresponding location error equation。 The motion error chain for the EDM is analyzed to develop a versatile error model. An entire Multiaxial EDM is analyzed as an example to determine its errors. The method provides a reference for Multiaxial EDM precision design.