Jarosław Gośliński

Performance Comparison of EKF-Based Algorithms for Orientation Estimation on Android Platform

Consumer electronics mobile devices, such as smartphones or tablets, are rapidly growing in computing power and are equipped with an increasing number of sensors. This enables to use a present-day mobile device as a viable platform for computation-intensive, real-time applications in navigation and guidance. In this paper, we present a study on the performance of the orientation estimation based on the data acquired by the accelerometer, magnetometer, and gyroscope in a mobile device. Reliable orientation estimation based on the readouts from inertial sensors may be used in more complex systems, e.g., to correct the orientation error of a visual odometry system. We present a rigorous derivation of the mathematical estimation model, and we thoroughly evaluate the performance of the orientation estimation mechanism available in the Android OS, and the proposed alternative solutions on an unique dataset gathered using an actual smartphone. From the experimental results, we draw the conclusions as to the best performing algorithm, and then we evaluate its execution time on Android-based devices to demonstrate the possibility of real-time usage. The Android code for the proposed orientation estimation system is made publicly available for scientific and commercial applications.

Estimation of Altitude and Vertical Velocity for Multirotor Aerial Vehicle Using Kalman Filter

Knowledge about precise robot localization is a key ingredient in controlling it, but the task is not trivial without any visual or GPS feedback. In this paper, authors concentrate on estimation of information about the robot’s altitude. One of the ways to acquire it, is a barometer. This type of sensor returns atmospheric pressure from which the height above the sea level can be computed. These readings have some disadvantages e.i.: vulnerability to pressure jumps and temperature drift as well as delay on the output. These problems can be solved by using Kalman filter algorithm for estimating altitude and vertical velocity, based not only on barometer readings, but also on accelerometer data. In the paper, derivation of the Kalman equations for the process to estimated are shown. Also improvements of the algorithm are described. The results of tests of this algorithm on real flying robot proved that estimates calculated with this method are precise and noise resistant.

Control of an Electro-Hydraulic Manipulator by Vision System Using Central Point of a Marker Estimated via Kalman Filter

In the paper, the vision system for control a electro-hydraulic manipulator is presented. The authors have proposed a Kalman Filter (KF) to estimate a central position of markers. Two different methods of initial estimation of markers position are used. First one is based on central point of marker’s mass. Second refers to a circle fitting method of binary object. These two methods theoretically give the same position of a central point of given marker, however, in case of image distortion results will have different errors. This can occur when operator is holding marker in a hand, and cover some parts of it. Therefore it is important to develop new robust method for marker tracking. Authors proposed Kalman Filter to estimate central point of a marker by making a fusion of information provided by two initial estimation methods. The conducted research proved that KF reduces total manipulator’s control error even in situation where \(30\,\%\) of marker area is invisible.

An Efficient PSO-Based Method for an Identification of a Quadrotor Model Parameters

This paper considers the method of Quadrotor’s model parameters identification. Nowadays, restrictions are being imposed on the drons, forcing their control algorithms to be robust and faultless. This can be partially ensured by Model Reference Adaptive Control (MRAC) as well as dedicated state estimators (e.g. Extended Kalman Filter). Although those methods can be easy implemented and used, in all scenario, the parameterized model is needed. In this work we proposed the identification method for parameters of the quadrotor’s orientation model, based on the PSO (Particle Swarm Optimization). We also add different physical aspects to model, so it can characterize the real Quadrotor more precisely. The conducted experiments shows that the PSO, can provide fast and reliable estimation of the model parameters. It also reveals interesting nature of the proposed models.

The Influence of the End Effector Gyroscopic Torques on a Base of the Manipulator

In this paper, the model of the robotic arm with payload is presented. The payload is configured as a rotating mass, which imitate the tool on a robot’s wrist. While manipulating with working tool the gyroscopic effect can occur. This leads to extra moments in each joint of the manipulator. In order to evaluate the scale of the process and the consequences in the robot’s trajectory, mathematical model of the robot including rotating mass was derived. The system was simulated for different parameters. It was proven that the gyroscopic effect cannot be neglected, especially when the robot’s movement are rapid and conducted simultaneously in more then one joint at once. For the purpose of the work, authors decided to use manipulator with five degrees of freedom, equipped with rotational joints only.

The High-Resolution Camera in Estimation of the Position of the Hydraulic Valve Spool

In the paper, the vision system for position measurement of the slider of proportional valve is presented. The valve spool’s slider was connected with a synchronous motor. The position was detected by industrial camera with a resolution of 1.6x1.2 kpixels. The research focused on the correctness of detection of the slider position. The use of the lens with the control aperture allowed to separate background from the object of research. The study confirms that it is possible to use vision system for measuring position of actuators in any hydraulic device. Future study will be narrowed to a measurement of a hydraulic cylinder pistons displacement in an application of a electro-hydraulic manipulator. This can significantly reduce the cost of mechanical sensors as well as shorten the overall time.