On-board Tests Research Articles

All-Day Object Tracking for Unmanned Aerial Vehicle

Unmanned aerial vehicle (UAV) has facilitated a wide range of real-world applications and attracted extensive research in the mobile computing field. Specially, developing real-time robust visual onboard trackers for all-day aerial maneuver can remarkably broaden the scope of intelligent deployment of UAV. However, prior tracking methods have merely focused on robust tracking in the well-illuminated scenes, while ignoring trackers capabilities to be deployed in the dark. In darkness, the conditions can be more complex and harsh, easily posing inferior robust tracking or even tracking failure. To this end, this work proposes a novel discriminative correlation filter-based tracker with illumination adaptive and anti-dark capability, namely ADTrack. ADTrack firstly exploits image illuminance information to enable adaptability of the model to the given light condition. Then, by virtue of an efficient enhancer, ADTrack carries out image pretreatment where a target aware mask is generated. Benefiting from the mask, ADTrack aims to solve a novel dual regression problem where dual filters are online trained with mutual constraint. Besides, this work also constructs a UAV nighttime tracking benchmark UAVDark135. Exhaustive experiments on authoritative benchmarks and onboard tests are implemented to validate the superiority and robustness of ADTrack in all-day conditions.

Stereo Orientation Prior for UAV Robust and Accurate Visual Odometry

This article presents a novel outlier rejection approach for feature-based visual odometry. The proposed approach is based on an empirical observation that shows that some 2D–3D correspondences with very low reprojection error can cause a high error in pose estimation. This work exploits such observations for odometry when a stereo camera is available. We argue that an explicit pose error measure is desired over that of implicit reprojection – whenever the former is possible – to classify correspondences into inliers versus outliers for the robust long-term odometry. To explicitly measure the plausible pose error, we derive bounds on the individual pose parameters with the help of the known orientation of stereo cameras. In this process, we formulate our bounds using the sum-of-square polynomials, which allow us to test whether a given correspondence satisfies any solution within the expected bounds. If the correspondence does not satisfy bounds for any parameter, it is considered to be an outlier. We implemented and tested the proposed method for the unmanned aerial vehicle (UAV) indoor navigation. The experiments from both benchmark evaluations (EuRoC and KITTI) and UAV onboard tests indicate that the inlier group refined by the proposed method significantly improves odometry estimation compared to the traditional outlier rejection methods. In fact, the proposed method performs as accurately as inertial measurement unit (IMU) aided methods in the state of the art. ROS project page (open-source code with demo video) is available at: <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">https://github.com/arclab-hku/SOPVO</uri>

Approbation of high-accuracy navigation technology for the benefit of Russia Ministry of Internal Affairs

With a view of implantation of space technology in activities of Ministry of Internal Affairs (MIA) and commercial organizations it is necessary to work through technology of robototechnical complex control in real application conditions. Aim. Investigation of reachable accuracy of coordinate definition of moving objects using global space navigation technology for the benefit of MIA. There are examined problems of coordinate definition accuracy increasing using global space navigation technology that were investigated in pilot project «MIA-Roscosmos». There are given results of onboard equipment tests that were worked in the regime of differential correction data using. There were used navigation apparatus of a geodesic class and the mobile measuring-diagnostic laboratory. There are defined possible field of application of navigation apparatus in an activities of MIA. There are formulated recommendations to using of global space navigation apparatus for the benefit of MIA.

A Cloud-based Quadruped Service Robot with Multi-Scene Adaptability and various forms of Human-Robot Interaction

Abstract With the development of CPS technology, more robots are endowed with intelligence to interact and communicate with humans such as service robot AIBO and AMWELL. These intelligent pets show great human-machine interactive ability by voice and face recognition, storytelling. However, they are limited only in family scenes and fail to provide cross-scene services. Therefore, we design a quadruped service robot called Cloud Sphinx - whose motion, voice, and vision system are driven by artificial intelligent models in the cloud. Our work pushes the interaction between CPS and humans. First, an open-source 12-DoF robotic cat is rapidly prototyped with a 3D printing technique, and its versatile gestures and gaits are coordinated by advanced servo control algorithms. Second, by merging motion control, NLP, image processing deep learning and cloud computing, Cloud Sphinx can provide services as emotion classification, face recognition, and garbage classification through human-robot interaction models. Third, an RaaS (Robot as a service) architecture is developed to fulfill the incrementally learning from the human-robot interaction processes. Sufficient simulations and on-board tests verify the human-robot interaction functionality and cross-scene service performances. Applications that we designed show the A.I. performance of service robots can be effectively enhanced by model training during the human-robot interactions and knowledge accumulation in cloud database.

Optimal Speed and Gear Shift Control of Long-haulage Trucks

Abstract Long haulage trucks consume large amounts of fuel, and fuel savings are desired both from economical and environmental aspects. When the upcoming road topology is known, the speed and gear shifts can be optimized in order to minimize the fuel consumption by e.g. minimizing the braking of the truck. Three different optimal control approaches are evaluated and compared for the speed and gear shift optimization problem. The results are based on simulations, but two of the three evaluated solvers are also implemented on-board a truck using rapid prototyping to investigate the feasibility of such systems. The results indicate that optimal control of the speed reduces the fuel consumption more than finding the optimal gear shift trajectory. The overall optimization problem contains one discrete and one continuous state, which makes the selection of optimization method complex. A sequential optimization scheme where the optimal speed profile is found using linear programming and the optimal gear profile is found using dynamic programming shows similar results as using dynamic programming for the overall problem simultaneously. One drawback with this solution is robustness and several tuning parameters. The driveability of the solutions are found good at the performed on-board tests.

Digital Signal Processing Approach to Identify the Boundary of Vehicle Idle Status during Operation

The MOVES is a tool to estimate on- and off-road emissions, in which 23 operating mode identification bins were defined based on vehicles’ specific power, speed, and acceleration. Bin 1 indicates an idling mode with the speed within 1.0 mph. However, the speed boundary in an earlier model of MOBILE 6.2 was 2.5 mph. Neither the change in the idling definition of the two models nor the speed boundary were investigated and discussed. This study proposed a method to theoretically redefine the idle boundary by characterizing vehicle emission rates. Vehicle speeds close to 0 mph were carefully studied based on 10,000-mile on-board emission tests in the state of Texas. A portable emission measurement system was used to detect real-time emissions from a 12-year-old gasoline light-duty vehicle, while the vehicle’s activity information was collected from an On-Board Diagnostic (OBD) II port. Power spectral density analysis was conducted on the collected emission and fuel consumption rates to identify a cut-off point that separates the frequency period with higher and lower energy. A Chebeshev I filter was designed to remove the high-frequency component to visualize the variables of emissions and fuel consumption on the vehicle’s moving trend lines. Based on observation and analysis results, 2.26 mph was identified as a boundary for an idle mode at an acceptance level of 95% significant change. It is recommended that the proposed method be applied to the emissions of more different types of vehicles with a wide range of mileages to validate the newly defined idle boundary.

Aural Discomfort Evaluation of Barometric Pressure in High-speed Train

Interior pressure of high-speed train varies when it passes through tunnels, which usually caused different levels of aural discomfort. As tympanic membrane (TM) plays a prominent role in pressure energy conversion and transmission, a finite element (FE) model including annular ligament (AL), pars flacidda (PF) and pars tensa (PT), was established in line with its anatomical structure. To quantitatively assess the barometric quality of train cabins, on-board tests were conducted to collect the interior pressure change history. Additionally, TM simulation in LS-DYNA was implemented to investigate the relationship between pressure changes and vibration characteristics. Based on the simulation results, displacement and velocity transfer function (VTF) of umbo were integrated as two indicators to judge aural discomfort and four discomfort levels were divided ranging from ideal, good, bad to worse. The results indicate that the threshold of displacement for each discomfort levels is 1.81μm, 2.10μm, 5.95μm and 11μm

Influence of Noble Metal and Promoter Capacity in CDPF on Particulate Matter Emissions of Diesel Bus

This study investigates the influence of noble metal capacity and promoter capacity in diesel oxidation catalysts (DOC) and catalyzed diesel particulate filters (CDPF) on particulate matter (PM) emissions. Four types of exhaust aftertreatments were applied to a diesel bus engine that meets the national Ⅲ emissions regulations. On-board tests were conducted respectively. PM emissions from the engine were strongly influenced by noble metal capacity in DOC and CDPF, especially at high speeds (the total number of particles increased by 70.8% when the noble metal capacity decreased by 5 g·ft-3 at 60 km·h-1). The higher the noble metal capacity was, the lower the PM emissions became, especially for PM in nuclei mode. The lanthanide material contributed to reducing PM emissions significantly. The content of precious metals could be reduced by 25% with proper lanthanide material, while the treatment effect of exhaust particles was guaranteed. In summary, aftertreatments are not sensitive to accelerating conditions, but the purification efficiency is obviously different under decontamination conditions.

A multi-laser sensor system to measure rolling deformation for truck tyres

The rolling deformation of a tyre is a direct result of tyre-road interactions and therefore contains useful information for tyre design. This study proposes a multi-laser sensor system for rolling tyre deformation measurements and the methodology is illustrated in detail. On-board validation tests were conducted with a truck tyre under service conditions. Tyre inner contour changes due to the inflation and wheel load were measured. In addition, non-uniform tread deformations were observed within the contact patch. In the longitudinal direction, asymmetric tread deformations which have direct links to rolling resistance were observed, while, in the lateral direction, the tread deformation pattern were found related to the inflation pressure and wheel load. The preliminary measurement results demonstrate the feasibility of the proposed system as a tool for investigations on tyre-road interactions and validations of virtual tyre models.

Integrated Navigation System for a Low-Cost Quadrotor Aerial Vehicle in the Presence of Rotor Influences

AbstractThe performance of navigation sensors may be seriously affected by the operating rotors of a drone. To address this kind of disturbance, a low-cost multisensor integrated navigation system was developed for a quadrotor aerial vehicle (QAV). The navigation board integrates a global positioning system (GPS) module, triaxial gyroscope, accelerometer, magnetometer, and a digital barometer. The sensors’ outputs were mathematically modeled and subsequently used in the integration Kalman filter. The data processing consisted of several steps: prefiltering, centralized filtering, and feedback. On the basis of onboard tests, the stochastic models of sensors were established in the presence of vibration, revolution, and ventilation caused by the QAV rotor’s operation, and in particular, its electromagnetic and aerodynamic characteristics. Flight experiments indicate that the proposed integrated navigation system can significantly improve flight accuracy and reliability.

Study of HTS Machine System Cooling With a Closed-Loop Thermosyphon: Stability of Unsteady Heat Load and Transient Conduction

Thermosyphoning (TS) is a heat exchange mechanism that uses a circulating refrigerant based on natural convection with no need for a mechanical pump. This cooling technique has been employed to circulate liquid coolant and gaseous coolant for high-temperature superconductor (HTS) rotating machine systems. These machines operate with an HTS field pole in the temperature range from 25 to 40 K, which are suitable temperatures for the survivability of HTS wires. The cryomechanical components are simple; there are a condenser, an evaporator, and adiabatic tubes located between the condenser and the evaporator. For applications to ship propulsion motors or generators of the radial gap type, the liquid/gas coolant flow along the adiabatic tube inside the rotating shaft may be considerably affected by the ship's rolling and/or pitching motion. In this work, we studied the temperature stability and heat load survivability of cryogenic TS, by constructing a 100 W @ 30 K-grade model. We investigated the temperature, thermal resistance, and heat flux, with a maximum load up to 60 W, of ground and onboard tests. The observed TS behavior indicates that there is sufficient survivability to assemble megawatt-class ship propulsion systems.

月基望远镜反射镜转台的热-结构耦合分析及验证

To improve the work performance of a 2;d mirror gimbal for the lunar;based telescope, the thermal;structural coupled analysis was carried out, and the analysis results were verified by thermal and onboard tests. according to the given input conditions, thermal loads and the thermal boundary, the finite element model was established to calculate the temperature fields of the mirror gimbal and main heating components. through inputting the temperature loads, preloads and the boundary conditions into the finite element model, the thermal deformation and stress of the u;shape structure, precision moving shafting systems and the worm gears were obtained. then, the expressions of friction moment were derived, and analytical data were used to the expressions to achieve the friction moment of shafting systems. on the basis of the friction moment, a proper moment motor was chosen. after calculation, the results show that the left shafting system has a larger friction moment at the low temperature condition of ;25, and the maximal one is up to 14.163 n·mm; while the friction moment is smaller under high temperature condition 55, and the maximal one is 4.796 n·mm. the results also show friction moment of the azimuth shafting systems at a low temperature condition of ;25 is 16.45 n·mm. moreover, the vertical shaft system shows its friction moment to be 16.45 n·mm at the low temperature condition of ;25, while it is zero at the high temperature condition because of shafting system unloading. the results indicate the reflection mirror gimbal works well between ;25 to 55. finally, the thermal and onboard tests were carried out to demonstrate the rationality and validity of the analysis results. © 2016, science press. all right reserved.

Лётные и полевые исследования видеоспектрометра для малого космического аппарата

Лётные и полевые исследования видеоспектрометра для малого космического аппарата

Precise Ionosphere Monitoring via a DSFH Satellite TT&amp;C Link

AbstractA phase-coherent and frequency-hopped PN ranging system was developed, originally for the purpose of anti-jamming TT&amp;C (tracking, telemetry and telecommand) of military satellites of China, including the Beidou-2 navigation satellites. The key innovation in the synchronization of this system is the unambiguous phase recovery of direct sequence and frequency hopping (DSFH) spread spectrum signal and the correction of frequency-dependent phase rotation caused by ionosphere. With synchronization achieved, a TEC monitoring algorithm based on maximum likelihood (ML) principle is proposed and its measuring precision is analyzed through ground simulation, onboard confirmation tests will be performed when transionosphere DSFH links are established in 2014. The measuring precision of TEC exceeds that obtained from GPS receiver data because the measurement is derived from unambiguous carrier phase estimates, not pseudorange estimates. The observation results from TT&amp;C stations can provide real time regional ionosphere TEC estimation.

Autonomous strapdown stellar-inertial navigation systems: Design principles, operating modes and operational experience

The paper considers stellar-inertial navigation systems (Stellar INS) for airborne and ground applications based on strapdown star tracker, strapdown inertial navigation system (SINS) and GNSS receiver. Specifications for optical and electronic components of star tracker are defined. Results from ground and onboard tests of Stellar INS model are provided. Various options of SINS stellar corrections are discussed.

On autonomous mode of GPS compass during long GNSS outages

The paper focuses on vehicle attitude determination by a MEMS-based inertial measurement unit (IMU) comprising magnetometers and one-axis FOG, a multiantenna GNSS receiver, and a log integrated in an integrated orientation and navigation system (IONS) for sea-going ships. IONS algorithms and errors in attitude determination in autonomous mode during long-term GNSS outages are investigated. Results from onboard tests of experimental GPS compass developed by Elektropribor in urban conditions are presented.

Normalized Coupling Method for Speed Synchronization of Multi-Axis Driving Vehicles

A new normalized coupling synchronization (NCS) method is proposed to solve the problem of synchronizing the speeds of all wheels in a multi-axis independent driving system without mechanical transmission connection. The NCS method integrates normalizing and coupling techniques by emulating mechanical line shaft. All wheels' speeds are normalized, and thus can be synchronized whether the wheel's revolution speeds are the same or different. Then, all of the normalized wheel speeds are coupled in order to eliminate speed synchronization errors between any pair of axes. Therefore, the new algorithm is able to achieve global speed synchronization. It is applicable to multi-axis driving vehicles either driving in straight line or making a turn. The conducted computational simulation shows that the proposed method gets better result in reducing speed synchronization errors in both cases of same and different wheel speeds compared to some classic speed sync methods in the literature. To further validate the effectiveness and applicability of the NCS method, it is also applied to a four-wheel-driving and four-wheel-steering vehicle for comparison tests. The onboard tests indicate that the proposed method achieves a fast convergence of speed error.

고속철도 제륜자 결함분석 및 제륜자 개발

고속철도 KTX 차량의 답면제동은 전기제동이 작용하지 않는 저속에서 열차를 정거장의 정위치에 정차시킬 때 주로 사용되는데 그 동안 균열발생, 제륜자 키 탈락 등 잦은 고장이 발생하였다. 본 연구에서는 이러한 고장의 원인을 규명하고 각 고장에 대해 해결책을 제시하고 시험평가를 통하여 개선효과를 검증하였다. 제륜자 키와 캠의 강도향상과 제륜자 마찰재 지지판의 강도향상은 제륜자 마찰재의 균열발생을 약간 줄이는 효과는 있었다. 지지판의 강도향상, 구조개선과 함께 제륜자의 재질을 변경하였을 때 마찰재에는 균열이 거의 발생되지 않았다. The shoe brake of the KTX is used in low speed when the electric brake is not effective. The main purpose of the shoe brake is to stop the train to a desired stop point at the station. Lots of defects have been encountered in the shoe brake unit since the KTX started its operation. To improve the reliability of shoe brake unit of the KTX power car, first of all, failure modes of the KTX shoe brake unit were analyzed. Main failure modes are cracks in the shoe friction material and fracture in the welded joints of the shoe backing steel structure. Several methods to remove the defects of the shoe brake unit were proposed and on-board tests were carried out: Increase of the strength of the shoe key and shoe cam, which decreased a little the occurrence of cracks in the shoe friction material; Redesign of the shoe backing steel structure, which eliminated the occurrence of the cracks in the backing plate but could not solve completely the crack problem in the shoe friction material; Development of a new friction material, which with redesign of the shoe backing steel structure could solve satisfactorily the crack problem in the shoe friction material.

드릴쉽 디젤엔진 발전기의 진동에 관한 연구

To obtain high power, diesel engines continuously increase combustion pressure and mean effective pressure each cylinder, and the excitation sources and noisy sources are increased, too. Moreover, to reduce the costs, shipyards make hull structures weaker than before. As above reasons, it is more difficult to control the vibration phenomenon nowadays.<BR> In this study, it was investigated why diesel generator sets reached the vibration allowable limits during the FAT and heavy vibration phenomenon of diesel generator sets using ODS test during onboard tests. Also, it is found out the stiffness of deck and common bed using the test result of their structural impedance. To find out the vibratory characteristics of diesel generator sets, model tests were carried out. From the sensitivity analysis after above tests, it was selected points to be reinforced and studied troubleshooting to solve heavy vibration phenomenon of diesel generator sets.

Quantitative evaluation of airborne sound insulation in ship’s accommodation using large scale noise test facilities

In recent years, the regulation on the airborne sound insulation index has become much more stringent as the increasing demand on the building of low noise vessels. So, some studies have been performed to improve the sound insulation in accommodation spaces. So far, however, the improvement has not been clearly obtained due to the complicated coupling relation between acoustic elements. In this paper, the onboard sound insulation tests for ship's accommodation spaces were firstly carried out to investigate the acoustic characteristics. Secondly, by using two reverberation rooms and a deckhouse mock-up having the same characteristics as a real ship, the sound transmission loss of cabin structures, such as ceiling, door, floor, and partition wall, were quantitatively evaluated and compared with in-situ test results. Through a series of tests, it was found that the airborne sound insulation in a ship's accommodation was greatly deteriorated by the door and the partition wall. The main acoustical effects dominating the flanking sound transmission in adjacent accommodation spaces were fully identified.