جستجوی مقالات مرتبط با کلیدواژه "ردیابی" در نشریات گروه "مکانیک"

The Kalman filter is a set of mathematical equations that is a computationally efficient tool for estimation. It provides us with the process status, in this way, it minimizes the mean square error. In some applications, this filter is very strong, it supports the past situation as well as the present and future situation. This mode is accurate for when the system model is also uncertain. The Kalman filter guides general problems trying to estimate the state x so that the discrete-time process is linearly controlled by a stochastic differential equation. The purpose of this article is to correctly track the target used in a radar with the help of the Kalman filter technique and MATLAB. The result of the implementation has been analyzed and planned for flight system maneuvers using a simulated target.

Template matching techniques are widely used today in image-based tracking systems to identify and track military targets. Due to their passivity, these systems are resistant to common electronic warfare techniques. One of the problems with using template matching algorithms is that they are slow, especially when rotation and scaling occur in targets relative to a predetermined pattern. In this paper, we perform an optimized algorithm for grayscale template-matching based on correlation coefficients which is invariant to scale and angle. The ‘brute force’ algorithm performs template-matching between the image to analyze and the template query shape rotated by specific angle, translated to specific scale. This takes too long and thus is no practical. The optimized algorithm includes three cascaded filters for scale, angle and template matching which results in probability of scaling, rotated angle for each pixel and point of template-matching, respectively. This algorithm accelerates searching and is 400 times faster than ‘Brute Force’ algorithm. By implementing hardware on the FPGA, it is possible to identify and track military targets at a speed of 10 frames per second.

Nowadays, safety is one of the most important principles in food industry and consumer preference. Regarding this issue, packaging units and transport industry are among the most critical points because food products can be contaminated easily by environmental factors. For this purpose, cutting edge technologies such as IoT (Internet of things) and blockchain are emerged. Smart things equipped with different sensors (temperature, humidity, location and etc.) can be created by using IoT, digital printing technologies and internet connection therefore safety management system can track and trace food products during packaging, transportation, retailing and consumer service. Usually data of transactions are susceptible to alteration so blockchain technology was introduced to record, track, and display accurate information in multiple nodes (computers) for all members' access. Blockchain technology makes a radically transparent environment with different advantages such as minimizing food spoilage and wastage, inhibition of fraud and tampering of packages, certifying organic and fair-trade origins of products, and recalling of contaminated products. This paper introduces the IoT and blockchain based technologies for tracking and tracing of packages in food supply chain.

This paper presents a model predictive control algorithm for path following of an autonomous vehicle in a curvilinear path. To define vehicles’, motion a nonlinear bicycle model of vehicle with 6 degrees of freedom is employed. Some kinematic constraints imposed to the state and control variables, as well as constraints on vehicle acceleration and braking deceleration for desired path following of the vehicle. Then, an appropriate prediction horizon and a quadratic optimization model is formulated and employed for minimizing the path following error and control variable’s variation of the vehicle. In the optimization computation process suitable weight coefficient for all state and control variables are considered. Finally, a simulation study is performed to analyze the capability and efficiency of the presented algorithm for following the desired path. The simulation results show that the presented path following algorithm is acceptably able to follow the desired path with acceptable accuracy and desirable speed.

This manuscript discusses the mathematical modeling of a serial manipulator connetcted byrotary joints and fixed on a non-holonomic wheeled moving base. The equations of motion ofthe system are obtained in a closed form using the Gibbs-Appell formulation. Then, newkinematics and dynamics based multivariable controllers are presented by using the predictivecontrol approach. The control laws are derived by minimizing a quadratic cost function for thepredicted tracking errors of the mentioned system. Finally, the performance of the suggestedcontroller is presented by simulating a mobile manipulator in simultaneous trajectory trackingof the mobile base and end-effector.

Nowadays, scientific and technological advances have created the ability to replace prosthetic legs with amputated limbs, which the design of a suitable controller is still being discussed by researchers. Therefore, according to the importance of the subject, in this paper, a combination of a nonlinear optimal control method based on the state-dependent Riccati equation approach with the integral state control technique is proposed for an active prosthetic leg for transfemoral amputees. The main objective of this paper is to optimize the energy consumption of the robot/prosthesis system and desirable tracking of the vertical displacement in hip and thigh and knee angles. Also, due to the robustness properties of the suggested controller is investigated sensitivity analysis against ±30% parametric uncertainty and compared with robust adaptive impedance control. The performance of the controller is assessed for both point-to-point motion and tracking modes by considering the saturation bounds of control signals. Finally, the simulation results show a decrease in control effort, desirable performance in tracking, and relatively good robustness in the presence of parametric uncertainty and constant disturbance. Numerical results indicate a significant reduction in energy consumption and total cost in this method compared to the robust adaptive impedance control.

In this paper, a continuous stable tracking control algorithm is proposed for spacecraft in the presence of unknown actuator failure, control input saturation and external disturbances. The design method is based on variable structure control and has the following properties: 1) fast and accurate response in the presence of bounded disturbances; 2) robust to the partial loss of actuator effectiveness; 3) explicit consideration of control input saturation. In contrast to traditional fault-tolerant control methods, the proposed controller does not require knowledge of the actuator faults and is implemented without explicit fault detection and isolation processes. In the proposed controller, a single parameter is adjusted dynamically in such a way that it is possible to prove the ultimate boundedness of both attitude and angular velocity errors. The stability proof is based on a Lyapunov direct method and the properties of the singularity free quaternion representation of spacecraft error dynamics. Results of numerical simulations state that the proposed controller is successful in achieving high attitude performance in the presence of external disturbances, actuator multiplicative faults, and control input saturation.