Wind-gust Compensation Algorithm based on High-gain Residual Observer to Control a Quadrotor Aircraft: Real-time Verification Task at Fixed Point

Abstract Aerodynamic lift force can affect automobile handling characteristics and wind gust can affect vehicle directional stability. Experimental measurements of the drag forces are usually made for fuel economy estimation and hence do not cover large wind angles that are important for vehicle stability studies of wind gust or extreme maneuvers. The Virtual Aerodynamic Wind Tunnel (VAWT) which uses PowerFlow is an ideal numerical tool in the early vehicle design stage to provide the aerodynamic forces from a vehicle model. The numerical technique is also advantageous over experimental measurements because it does not need a hardware prototype and the computer model is relatively easier to set up for design iterations. Since the dynamic effects of aerodynamic forces on a vehicle and its driver are best studied with a driving simulator in a real time environment, the VAWT calculated air drag coefficients are reduced to a mathematical function suitable for the real time driving simulations. Available test measurements are used to ensure the practicability of the mathematical function. A vehicle model is then used to test the aerodynamic model and study the effects of the aerodynamics on the vehicle directional stability.

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Real-Time Mode Switching and Beam Scanning of High-Gain OAM Waves Using a 1-Bit Reconfigurable Reflectarray Antenna

Electronics ◽

10.3390/electronics9122181 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2181

Author(s):

Ziyang Wang ◽

Xiaotian Pan ◽

Fan Yang ◽

Shenheng Xu ◽

Maokun Li

Keyword(s):

Real Time ◽

Dimensional Space ◽

Large Angle ◽

High Gain ◽

Mode Switching ◽

Effective Control ◽

Vortex Beam ◽

Beam Scanning ◽

The Future ◽

Reflectarray Antenna

A reconfigurable electromagnetic surface has been studied to realize the adjustable orbital angular momentum (OAM) beams for real-time wireless communication and dynamic target detection in the future. OAM mode switching realized by many previous designs suffers from low gains without OAM beam scanning. In this article, a 1-bit reconfigurable reflectarray antenna is designed, fabricated, and tested for the real-time control of OAM mode switching and large-angle vortex beam scanning in three-dimensional space. The proposed reflectarray surface is composed of 1-bit electronically reconfigurable cells, and the size is 24 λ × 24 λ with 2304 units. The reconfigurable element is designed by using a radiation patch loading a PIN diode with effective control of two states, “ON” and “OFF”, for the demand of 180° phase difference. The reflectarray surface can be assigned to a code sequence of 0 or 1 by the Field-Programmable Gate Array (FPGA) in real time. Henceforth, the coding surface can dynamically control the generation of high-gain OAM beams, where only the optimized phase distributions on the surface need to be changed according to demand. To verify the concept, a large-scale reflectarray surface is fabricated and measured with an oblique feed at 15°. Different OAM-carrying phase distributions for different OAM beam states are calculated and tested. The test results show that the OAM mode switching between l = 1 and l = 2 is realized, and other variable modes such as l = 3 or l = 5 can also be achieved by modifying the phase encoding sequence. Furthermore, the direction of the vortex beams can be accurately controlled with gains over 20 dBi, and the large-angle vortex beam scanning is verified. Therefore, all results demonstrate that the proposed 1-bit reconfigurable reflectarray is efficient for the regulation and control of OAM-carrying beams for the demand of real-time dynamic wireless communications in the future.

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Dynamic Motion Planning for Autonomous Assistive Surgical Robots

Electronics ◽

10.3390/electronics8090957 ◽

2019 ◽

Vol 8 (9) ◽

pp. 957 ◽

Cited By ~ 1

Author(s):

Alessio Sozzi ◽

Marcello Bonfè ◽

Saverio Farsoni ◽

Giacomo De Rossi ◽

Riccardo Muradore

Keyword(s):

Dynamical System ◽

Fixed Point ◽

Motion Planning ◽

Real Time ◽

Surgical Robots ◽

Dynamic Changes ◽

Dynamic Motion ◽

Dynamic Motion Planning ◽

Trajectory Generator ◽

Mechanical Constraint

The paper addresses the problem of the generation of collision-free trajectories for a robotic manipulator, operating in a scenario in which obstacles may be moving at non-negligible velocities. In particular, the paper aims to present a trajectory generation solution that is fully executable in real-time and that can reactively adapt to both dynamic changes of the environment and fast reconfiguration of the robotic task. The proposed motion planner extends the method based on a dynamical system to cope with the peculiar kinematics of surgical robots for laparoscopic operations, the mechanical constraint being enforced by the fixed point of insertion into the abdomen of the patient the most challenging aspect. The paper includes a validation of the trajectory generator in both simulated and experimental scenarios.

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The On-Board Measurement of Diesel Vehicle Smoke Intensity System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.220-223.684 ◽

2012 ◽

Vol 220-223 ◽

pp. 684-688

Author(s):

Hong Yan Chen ◽

Yi Jin Song

Keyword(s):

Fixed Point ◽

Real Time ◽

Exhaust Emission ◽

Vehicle Exhaust ◽

Diesel Vehicle

To real-time monitor vehicle exhaust emission under daily running, this paper proposed a on-board measurement of diesel vehicle smoke intensity system based on GSM/GPRS and GPS, and concentrated on the design of hardware and software of the vehicle mounted terminal. This paper broke the traditional fixed-point way to sample exhaust data and could acquire data of different section, different vehicle types and different time.

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