Development of laboratory devices for real-time measurement of object 3D position using stereo cameras

Measuring the 3D position at any time of a given object in real-time automatically and well documented to understand a physical phenomenon is essential. Exploring a stereo camera in developing 3D images is very intriguing since a 3D image perception generated by a stereo image may be reprojected back to generate a 3D object position at a specific time. This research aimed to develop a device and measure the 3D object position in real-time using a stereo camera. The device was constructed from a stereo camera, tripod, and a mini-PC. Calibration was carried out for position measurement in X, Y, and Z directions based on the disparity in the two images. Then, a simple 3D position measurement was carried out based on the calibration results. Also, whether the measurement was in real-time was justified. By applying template matching and triangulation algorithms on those two images, the object position in the 3D coordinate was calculated and recorded automatically. The disparity resolution characteristic of the stereo camera was obtained varied from 132 pixels to 58 pixels for an object distance to the camera from 30 cm to 70 cm. This setup could measure the 3D object position in real-time with an average delay time of less than 50 ms, using a notebook and a mini-PC. The 3D position measurement can be performed in real-time along with automatic documentation. Upon the stereo camera specifications used in this experiment, the maximum accuracy of the measurement in X, Y, and Z directions are ΔX = 0.6 cm, ΔY = 0.2 cm, and ΔZ = 0.8 cm at the measurement range of 30 cm–60 cm. This research is expected to provide new insights in the development of laboratory tools for learning physics, especially mechanics in schools and colleges.

Comparative Analysis of the Indirect Calorimetry and the Metabolic Power Method to Calculate Energy Expenditure in Team Handball

Monitoring physical activity, e.g., training load and energy expenditure (EE), is important to optimize the training process in various sports. Especially in team handball, where there is little information about EE in training and competition. The objective of the study was to compare EE in team handball derived from a respiratory gas exchange analysis (spiroergometry) and a local position measurement (LPM) system. Eleven participants completed a validated, team handball game-based performance test and wore a portable spiroergometry system (K5 Cosmed) and an LPM transponder (Catapult ClearSky T6). EE was determined via indirect calorimetry for spiroergometry data and via the metabolic power model for EE for LPM data. EE estimated via the metabolic power model was −66 to −63 ± 12% lower than via indirect calorimetry (p < 0.001, pη2 = 0.97). No correlation was found for the overall test (r = 0.32, p = 0.34), nor for every single heat (r ≤ 0.44, 0.18 ≤ p ≤ 0.99). Therefore, regression analyses predicting spiroergometry data based on LPM data were not feasible. In line with previous studies, the metabolic power model for EE in team handball (including short-distance movements, great accelerations, and non-locomotive actions) is not suitable.

Output-Feedback Position Tracking Servo System with Feedback Gain Learning Mechanism via Order-Reduction Speed-Error-Stabilization Approach

This paper presents a novel trajectory-tracking technique for servo systems treating only the position measurement as the output subject to practical concerns: system parameter and load uncertainties. There are two main contributions: (a) the use of observers without system parameter information for estimating the position reference derivative and speed and acceleration errors and (b) an order reduction exponential speed error stabilizer via active damping injection to enable the application of a feedback-gain-learning position-tracking action. A hardware configuration using a QUBE-servo2 and myRIO-1900 experimentally validates the closed-loop improvement under various scenarios.

Why do we choose the fastest point as a reference to measure the simple pendulum period by a stopwatch?

Since the vibration of a single pendulum is very periodic, measuring its period is a very interesting topic. When students are asked to measure the period of a single vibration, they start and stop the stopwatch when the pendulum reaches the top point as a reference point. In this paper, we try to show that the error can be reduced more by using the equilibrium point, that is, the bottom position as the reference rather than the top position. We think it would be beneficial for students to measure the period in both cases, compare the errors, and think about the reasons for error differences. Students believe that the moment the pendulum moved slowly and nearly stopped at the top was more likely to measure the time to be more accurate. The reason for this is that they think the pendulum will move so fast when it passes the bottom point that they will not be able to start or stop the stopwatch accurately at the instant passing the lowest point. We are also able to obtain the error of the position measurement by using the recorded video of a simple pendulum.

Lightweight Design of Patch Plate on Car-body B-pillar based on Side Impact Safety

The B-pillar of automobile needs to meet the requirements of vehicle strength and rigidity, and also consider the fuel economy of vehicle. Therefore, the design and development of B-pillar is a difficult point in the field of car body design and manufacturing. Based on the side impact regulations, the safety model ling and simulation analysis of the B-pillar of the vehicle was carried out to obtain the change law of the intrusion amount and the intrusion speed of the five key points in the whole process. According to the analysis results of side impact of B-pillar, a scheme to reduce the material thickness of B-pillar body and increase patch plate for lightweight design was proposed, and a comparative analysis of the safety of side impact was made. In view of the problem that the intrusion of B-pillar of a real vehicle model did not conform to the regulations, the design scheme of adding patch plate was proposed to improve the safety of side impact. According to the actual collision results, the simulation model was modified, and the design scheme was simulated and optimized. The reliability of the design scheme was verified by the real vehicle collision analysis. The results show that: in the side collision of B-pillar, the intrusion of D2 position measurement point is the largest, the intrusion velocity of D3 position measurement point is the largest, and the intrusion amount and intrusion speed of D5 position measurement point are the smallest. Patch plates are added to the inner side of adjacent area of D2 position measurement point. The welding point is welded with B-pillar structure, and other areas of B-pillar keep the same structure, so as to realize lightweight and effective improvement of safety. Under the condition of maintaining the original material and thickness of B-pillar, two patches with thickness of 2 mm and material of B340LA are added in the middle of B-pillar to improve the structural strength. The defect area is set at the wrinkle position of the original B-pillar to guide the deformation mode of the B-pillar. The relative deviation between simulation calculation and test intrusion is less than 20 %, and the car crash simulation model with improved B-pillar structure is more accurate. For this type of car, the optimization and improvement effect of B-pillar structure is ideal, which improves the passenger safety protection ability in side impact.

Development and Experimental Validation of an Intelligent Camera Model for Automated Driving

The virtual testing and validation of advanced driver assistance system and automated driving (ADAS/AD) functions require efficient and realistic perception sensor models. In particular, the limitations and measurement errors of real perception sensors need to be simulated realistically in order to generate useful sensor data for the ADAS/AD function under test. In this paper, a novel sensor modeling approach for automotive perception sensors is introduced. The novel approach combines kernel density estimation with regression modeling and puts the main focus on the position measurement errors. The modeling approach is designed for any automotive perception sensor that provides position estimations at the object level. To demonstrate and evaluate the new approach, a common state-of-the-art automotive camera (Mobileye 630) was considered. Both sensor measurements (Mobileye position estimations) and ground-truth data (DGPS positions of all attending vehicles) were collected during a large measurement campaign on a Hungarian highway to support the development and experimental validation of the new approach. The quality of the model was tested and compared to reference measurements, leading to a pointwise position error of 9.60% in the lateral and 1.57% in the longitudinal direction. Additionally, the modeling of the natural scattering of the sensor model output was satisfying. In particular, the deviations of the position measurements were well modeled with this approach.

On the Quantum Mechanical Description of the Interaction between Particle and Detector

Quantum measurements of physical quantities are often described as ideal measurements. However, only a few measurements fulfil the conditions of ideal measurements. The aim of the present work is to describe real position measurements with detectors that are able to detect single particles. For this purpose, a detector model is developed that can describe the time dependence of the interaction between a non-relativistic particle and a detector. The example of a position measurement shows that this interaction can be described with the methods of quantum mechanics. At the beginning of a position measurement, the detector behaves as a target consisting of a large number of quantum mechanical systems. In the first reaction, the incident particle interacts with a single atom, electron or nucleus, but not with the whole detector. This reaction and all following reactions are quantum mechanical processes. At the end of the measurement, the detector can be considered as a classical apparatus. A detector is neither a quantum mechanical system nor a classical apparatus. The detector model explains why one obtains a well-defined result for each individual position measurement. It further explains that, in general, it is impossible to predict the outcome of an individual measurement.

Implementation of the DCS System for the validation of MM HV Boards and the DCS System of the new BIS78 Chambers for the upgrade of muon system of the ATLAS Experiment

The ATLAS Muon Spectrometer is going through upgrades on the Phase I in order to achieve higher rates for the upcoming LHC runs. The two main projects of this Phase I upgrade are the New Small Wheels (NSW), which are expected to complement the ATLAS muon spectrometer in the end-cap regions and a smaller size project, known as BIS78 (Barrel Inner Small sectors). The NSW is expected to replace the Small Wheel (SW) and it will be installed in the ATLAS underground cavern during the summer by the end of the LHC Long Shutdown 2. This new system will be consisted by two prototype detectors, the sTGC (small Thin Gas Chambers) and the resistive Micromegas (MM). In order to cope with higher LHC luminosities, the installation of NSW will help the reduction of the trigger rate in the forward region. With half of the rate in the barrel-endcap transition region reduced by the existing TGCs, the other half of the fake trigger rate in transition region will be reduced by the new BIS78 stations. The BIS78 subproject foresees the replacement of the existing Monitored Drift Tubes (MDTs), used for the precise position measurement in this area, with muon stations formed by integrated smaller diameter tubes (sMDT) and a new generation of RPCs, capable of withstanding the higher rates and provide a robust standalone muon confirmation. The existing BIS7 and BIS8 MDT Chambers will be replaced by 16 new muon stations of one small (sMDT) chamber and two RPC triplets, and it will be the pilot project for the Phase II BI Upgrade. This work is divided into two parts. First will be presented the development and the implementation of a Detector Control System (DCS) for the HV system for the MM detectors of NSW and specifically the validation of a new type of HV Boards (A7038AP). Second, the development of the DCS for the monitoring and operation of the new sMDT chambers of the MDT Sub-System will be presented.