This paper is concerned with the design of Stability/Control Augmentation System (S/CAS) for small Quad Tilt Wing (QTW) Unmanned Aerial Vehicle (UAV) which has been developed as a test bed for ...guidance and control system demonstrations. We design the basic S/CAS for the aircraft using our previously proposed design method. By comparing the eigenvalues of linearized motions of the newly developed and the previously developed QTWUAVs, the effectiveness of our method for S/CAS design is illustrated. We also show the flight test results using our S/CAS.
Gyroscope is widely spreading in automobile technologies such as Electronic Stability Control (ESC) and crashtesting devices. Traceability for test equipment of gyroscopes is discussed and will soon ...be required in the UnitedStates, Europe, Japan and other countries. To meet the upcoming calibration needs, we are developing an angularvelocitycalibration system based on a self-calibratable rotary encoder (SelfA), which is the same type as nationalprimary angle standard. In this paper, we tested out the developed calibration system by means of three commercialgyroscopes, experimentally ranging up to 300 °/s. The rotating stability and electrical noise is suitable for calibrationof the gyroscopes.
▶ A meta-analysis was conducted of 12 studies of the effects of ESC on crashes. ▶ Results indicate that ESC prevents ca. 40% of all crashes involving loss of control. ▶ Multiple vehicle crashes were ...found to be largely unchanged. ▶ Behavioural adaptation is not likely to offset the positive safety effects.
The present study is an update of the meta-analysis by Erke (Erke, A., 2008. Effects of Electronic Stability Control (ESC) on accidents: a review of empirical evidence. Accident Analysis & Prevention, 40 (1), 167–173). Results from 12 studies of the effects of Electronic Stability Control (ESC) on the number of different types of crashes were summarized by means of meta-analysis. The results indicate that ESC prevents about 40% of all crashes involving loss of control. The greatest reductions were found for rollover crashes (−50%), followed by run-off-road (−40%) and single vehicle crashes (−25%). These results are however likely to be somewhat overestimated, especially for non-fatal crashes. Multiple vehicle crashes were found to be largely unchanged. Reductions were found for some types of multiple vehicle crashes. Rear-end collisions are unchanged or may increase. Fatal crashes involving pedestrians, bicycles or animals were found to increase as well. ESC was found to be more effective in preventing fatal crashes than non-fatal crashes. ESC is often found to be more effective in Sports Utility Vehicles (SUVs) than in passenger cars. This may be due to differences between drivers of SUVs and passenger cars. The results from meta-analysis indicate that drivers of ESC-equipped vehicles are likely to be safer drivers than other drivers. All the same, ESC may lead to behavioural adaptation in some cases, but it is not likely that behavioural adaptation offsets the positive safety effects. This may be due to a lack of knowledge about ESC.
•The controller of GSC and MSC of DFWPG system is designed based on Hamilton realization.•Realizing a rapid response of the dc bus voltage control by output feedback control strategy.•Realizing ...grid-side unit power factor control of doubly-fed wind power generation system.•Comparing with transient response effects of PI control in Matlab/Simulink environment.
With the nonlinear characteristic of doubly-fed wind power generation (DFWPG) system, Hamilton realization based on analytical mechanics plays a significant role in the system problems of stability analysis and controller design. Hamilton system expression of grid-side converter (GSC) and machine-side converter (MSC) is obtained and the stability control is designed with Lagrange theory of analytical mechanics in this paper. Firstly, to obtain the differential equations which satisfy satisfies self-adjoint conditions, coordinate transformations of dynamic equations of GSC and MSC are conducted. The system Hamilton function and Hamilton realization expression are determined based on Euler–Lagrange process and generalized force method. On the basis of feedback control theory the controller is designed, which can make the system tend to be asymptotically stable in the neighborhood of the equilibrium point. With Hessian matrix positive-definite the Hamilton system is determined to be stable. Additionally, within Matlab/Simulink environment, the transient simulation of DFWPG system is carried out and the effectiveness of controller derived in this paper is verified, by comparisons of response effects with PI control and regulation performances under different wind speeds. The rapid response of the dc bus voltage control, grid-side unit power factor control, a maximum capture of wind energy can be realized, using control design process of Hamilton realization. The system analysis and control design process of Hamilton realization have broad prospects of applications and developments.
This paper presents a new approach to semi-autonomous vehicle hazard avoidance and stability control, based on the design and selective enforcement of constraints. This differs from traditional ...approaches that rely on the planning and tracking of paths. This emphasis on constraints facilitates "minimally-invasive" control for human-machine systems; instead of forcing a human operator to follow an automation-determined path, the constraint-based approach identifies safe homotopies, and allows the operator to navigate freely within them, introducing control action only as necessary to ensure that the vehicle does not violate safety constraints. The method evaluates candidate homotopies based on "restrictiveness", rather than traditional measures of path goodness, and designs and enforces requisite constraints on the human's control commands to ensure that the vehicle never leaves the controllable subset of a desired homotopy. Identification of these homotopic classes in off-road environments is performed using geometric constructs. The goodness of competing homotopies and their associated constraints is then characterized using geometric heuristics. Finally, input limits satisfying homotopy and vehicle dynamic constraints are enforced using threat-based feedback mechanisms to ensure that the vehicle avoids collisions and instability while preserving the human operator's situational awareness and mental models. The methods developed in this work are shown in simulation and experimentally demonstrated in safe, high-speed teleoperation of an unmanned ground vehicle.
Our laboratory has recently described a stability control region in the two-stranded α-helical coiled-coil α-tropomyosin that accounts for overall protein stability but is not required for folding ...(Hodges et al., 2009). We have used a synthetic peptide approach to investigate three stability control sites within the stability control region (residues 97–118). Two of the sites, electrostatic cluster 1 (97–104, EELDRAQE) and electrostatic cluster 2 (112–118, KLEEAEK), feature sequences with unusually high charge density and the potential to form multiple intrachain and interchain salt bridges (ionic attractions). A third site (105–111, RLATALQ) features an e position Leu residue, an arrangement known previously to enhance coiled-coil stability modestly. A native peptide and seven peptide analogs of the tropomyosin sequence 85–119 were prepared by Fmoc solid-phase peptide synthesis. Thermal stability measurements by circular dichroism (CD) spectroscopy revealed the following Tm values for the native peptide and three key analogs: 52.9°C (Native), 46.0°C (R101A), 45.3°C (K112A/K118A), and 27.9°C (L110A). The corresponding ΔTm values for the analogs, relative to the native peptide, are −6.9°C, −7.6°C, and −25.0°C, respectively. The dramatic contribution to stability made by L110e is three times greater than the contribution of either electrostatic cluster 1 or 2, likely resulting from a novel hydrophobic interaction not previously observed. These thermal stability results were corroborated by temperature profiling analyses using reversed-phase high-performance liquid chromatography (RP-HPLC). We believe that the combined contributions of the interactions within the three stability control sites are responsible for the effect of the stability control region in tropomyosin, with the Leu110e contribution being most critical.
Electronic stability control (ESC) is a vehicle safety system designed to keep vehicles moving in the direction commanded by the driver and thereby prevent loss-of-control crashes. Previous research ...has shown that ESC has been highly effective at reducing road departures related to loss of control. ESC is mandatory in all U.S. passenger vehicles manufactured from model year 2012 onward; by a 2014 estimate, ESC is in approximately one-third of passenger vehicles on the road. The proliferation of ESC may therefore alter benefit-to-cost ratios for roadside barriers. The objective of this analysis was to determine the effect of ESC on fatal crashes with roadside barriers. This objective was a first step toward determining whether ESC reduced the overall rate of crashes with roadside barriers and whether ESC had any effect on impact conditions or injury outcomes in barrier crashes. For cars, ESC reduced the odds of fatal crashes with roadside barriers by about 50% and reduced the odds of fatal rollovers that occurred in association with roadside barriers by about 45%. For light trucks and vans, ESC reduced barrier fatality odds by about 40% and barrier-associated rollover fatality odds by about 55%. By 2028, when an estimated 75% of passenger vehicles will have electronic stability control, ESC will have the potential to prevent about 410 out of an estimated 1,180 possible barrier-related fatalities per year. In the long term, once installed in every U.S. passenger vehicle, ESC could prevent about 550 of those same 1,180 possible barrier-related fatalities each year.
For a distributed drive electric vehicle (DDEV) which is equipped with redundant actuators, allocation control is a key technique. Three different allocation control algorithms are designated with ...fixed efficiency matrix, dynamic efficiency matrix, and direct yaw moment distribution, respectively. All these algorithms are applied in a vehicle stability control system with hierarchical control structure and evaluated from three aspects, namely, control precision, real-time characteristics, and control energy. Comparison results demonstrate that the algorithm with dynamic efficiency matrix has the best comprehensive performance, which is also validated in field tests based on a DDEV equipped with four motors.
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