Yaw Angular Velocity Research Articles

Computation of Satellite Yaw Angular Velocity for Relative Radiometric Calibration

The purpose of relative radiometric calibration is to eliminate the strip phenomenon on the image. A new method with all detectors viewing the same scene is carried out. This paper provides the modeling and computation of satellite Yaw Angular Velocity(YAV) based on all the CCD detectors imaging the same region. The space coordinate transform process from object point on the earth to image point in the focal plane is found. Furthermore, the calculation method and process of YAV for satellite CCD camera imaging the same scene is given. Computation results indicate that the ground trajectory interval width is less than one pixel near the equator, and about four pixels below 35 degrees during calibration process more than 30 seconds imaging for 30000 detectors imaging the same scene.

Vehicle Speed Estimation in Driving Mode for Hybrid Electric Car Using Unscented Kalman Filter

As for the four-wheel drive hybrid electric car with complex and changeable driving modes, unscented Kalman filter(UKF) is proposed for vehicle speed estimation in consideration of obtainable driving torque and electronic stability program(ESP) senor signals. Simulation platform is established according to the four-wheel drive hybrid electric car, which integrates power-train system model, nonlinear seven degree of freedom vehicle dynamics model and the dynamic union tire model. The estimation result of UKF algorithm is compared with the simulated real car's velocity. After steering wheel angle sensor, yaw angular velocity sensor and acceleration sensors are all mounted in the prototype car and the signals of two front wheel angular speed are acquired as well as the torque information of driving wheel are introduced, UKF algorithm is tested on the real vehicle road experiments, which include 8-shape route driving case on pure electric drive mode, double-lane change driving case and S-shape route driving case on four wheel hybrid drive mode. Simulation and test results show that the proposed algorithm has not only high precision, but also strong adaptability.

Development of Robotic Unicycles

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260005/02.jpg"" width=""300"" />Robotic Unicycle in stable driving</div> This paper introduces the first successful development of a robotic unicycle imitating a human rider. The robot consists of a body supported on a single wheel, a closed linkage on each side of the body to drive the wheel, and a rotor on the top. The effects of the closed link, gyro effect, centrifugal force, and reaction torque of the rotor on the robot’s stability and direction were investigated in simulations and experiments. Stability and drive principles of the robotic unicycle were proposed. The unicycle accelerated or decelerated because of the location of the compound center of gravity. Direction control was proposed based on the proposed acceleration control rule and a specified yaw angular velocity. Using that rule, drive simulations of tracing a circle and a “number 8” were conducted. The computer simulations demonstrated stable driving of the robotic unicycle. The experimental evaluation, velocity, and direction control of the robot were also studied. The principles of postural stability and driving of the robotic unicycle were clarified. </span>

Numerical Simulation of the Kinetic Energy Projectile Deflected by Targets Moving along Transverse Direction

When the kinetic energy projectile into concrete target movement, angle of attack can affect the penetration process of ballistic performance, resulting deflection effect, thus affecting the penetration depth. For the analysis of kinetic energy projectile penetrating the lateral movement of the target deflection model, using the finite element simulation software for lateral movement of the target missile penetrates the process of numerical simulation. The results showed that: rigid lateral movement of the target missile and projectile kinetic energy projectile velocity has some deflection effect. Playing the role of the kinetic energy of the lateral movement of the target, the missile body yaw angular velocity increases and then decreases after the first, but not so obvious kinetic energy projectile yaw.

Research on Effect of Locking Ratio of Limit-Slip Differential on Handling Stability of FSAE Racing Car

A nonlinear four-wheel dynamics vehicle model which includes a limit-slip differential model based on FSAE racecar is established and the typical conditions are designed according to track requirement. The effect of different locking ratio on vehicle handling stability has been researched .The simulation results shows that: with the increase of locking ratio, the steering radius ratio increase, both peak lateral acceleration and yaw angular velocity reduce, and the changing trend of value is flat. But the average acceleration increase with the locking ratio until the latter reach a specific value under the condition of Slaloms.

Interpersonal Coordination of Head Motion in Distressed Couples.

In automatic emotional expression analysis, head motion has been considered mostly a nuisance variable, something to control when extracting features for action unit or expression detection. As an initial step toward understanding the contribution of head motion to emotion communication, we investigated the interpersonal coordination of rigid head motion in intimate couples with a history of interpersonal violence. Episodes of conflict and non-conflict were elicited in dyadic interaction tasks and validated using linguistic criteria. Head motion parameters were analyzed using Student's paired t-tests; actor-partner analyses to model mutual influence within couples; and windowed cross-correlation to reveal dynamics of change in direction of influence over time. Partners' RMS angular displacement for yaw and RMS angular velocity for pitch and yaw each demonstrated strong mutual influence between partners. Partners' RMS angular displacement for pitch was higher during conflict. In both conflict and non-conflict, head angular displacement and angular velocity for pitch and yaw were strongly correlated, with frequent shifts in lead-lag relationships. The overall amount of coordination between partners' head movement was more highly correlated during non-conflict compared with conflict interaction. While conflict increased head motion, it served to attenuate interpersonal coordination.

Integrated Design for Steering System and Suspension

A design method of integrated control for suspension system and steering system is proposed based on vehicle ride comfort and handling stability. A car simulation model is built applying the software of MATLAB and ADAMS. The construction and characteristic of the integrated simulation model of the suspension system and steering system is illustrated in detail which uses fuzzy method and PID method. Using the simulation model, body vertical acceleration, roll angle and yaw angular velocity are measured in three status which include no control condition, the individually control for active suspension, and the integration control respectively. The simulation data show that the integrated control method synchronously ensures the ride comfort and handling stability.

Nonlinear feedback control and trajectory tracking of vehicle

This paper mainly studies nonlinear feedback control applied to the nonlinear vehicle dynamics with varying velocity. The main objective of this study is the stabilisation of longitudinal, lateral and yaw angular vehicle velocities. To this end, a nonlinear vehicle model is developed which takes both the lateral and longitudinal vehicle dynamics into account. Based on this model, a method to build a nonlinear state feedback control is first designed by which the complexity of system structure can be simplified. The obtained system is then synthesised by the combined Lyapunov–LaSalle method. The simulation results show that the proposed control can improve stability and comfort of vehicle driving. Moreover, this paper presents a lemma which ensures the trajectory tracking and path-following problem for vehicle. It can also be exploited simultaneously to solve both the tracking and path-following control problems of the vehicle ride and driving stability. We also show how the results of the lemma can be applied to solve the path-following problem, in which the vehicle converges and follows a designed path. The effectiveness of the proposed lemma for trajectory tracking is clearly demonstrated by simulation results.

A Physical Interpretation of Lead Time Constant of Yaw Angular Velocity in Planar Motion of Automobile

This paper discusses lead time constant of yaw angular velocity based on equations of motion of automobiles in planar motion. However, the equations of motion are too complex to be interpreted because the steering angle input generates two variables, lateral and yaw angular accelerations simultaneously. Under reasonable assumption, I derive an equivalent transformation models that generates only one acceleration value from the equations of motion. To generate only one variable against steering input, rigid body of an automobile is replaced by two particles located at the front and rear axles. The equations of motion of the equivalent transformation models imply a mechanism of automobiles transient behavior as follows. Steering angle input causes a yaw angular acceleration around the rear axle. This acceleration changes into a yaw angular velocity by time integration. The yaw angular velocity causes an attitude angular velocity of the rear axle. The velocity changes into an attitude angle at the rear axle by time integration. This attitude angle generates a yaw angular acceleration as restoring yaw moment. In this equivalent transformation models, lead time constant of the yaw angular velocity implies time difference between the yaw angular velocity and attitude angle at the rear axle. Therefore the lead time constant is suitable for criteria of behavior of the automobile at the rear axle. Furthermore the equations of motion will introduce a control law to improve automobile dynamic behaviors.

Navigation Method for Underwater Vehicles Based on Mutual Acoustical Positioning With a Single Seafloor Station

In this paper, we propose a novel navigation method for underwater vehicles based on a single seafloor station (SS), with which the vehicles can estimate their positions and orientations with respect to the SS without the need of expensive inertial navigation system or time-consuming calibration. This method is suitable for near-seafloor applications requiring real-time and accurate positioning, such as seafloor imaging and sampling. The method is also suitable for autonomous underwater vehicles (AUVs) since no other external aid is necessary other than SS. The key idea is to utilize mutual acoustical measurements between the vehicle and the SS. Simply explained: 1) the vehicle starts by interrogating the SS acoustically and measures the range between the two units as well as the bearing of the SS with respect to the vehicle in the vehicle reference frame; and then, 2) the SS computes the bearing of the vehicle with respect to the SS and transmits this information back to the vehicle using a similar acoustical device. By combining this information and inputting it into a nonlinear filter structure that includes measurements of the vehicle's ground velocity and yaw angular velocity, the vehicle computes its position and heading estimates. A pair of acoustical devices named acoustical localization and communication (ALOC) devices that can communicate and calculate their relative positions have been built. Sea trials were carried out in October 2011 using the AUV Tri-Dog1 (TD) and a trial SS at Kagoshima Bay in Japan. The AUV successfully navigated around the SS based on the measurements of the ALOC device mounted on both the AUV and the SS. The performance of the method was verified through simulations based on the experimental results.

No Steady-State Error Tracking Control of Multi-Axle Steering Vehicle

In order to improve the interference suppression capability for the muti-axle steering vehicle(MASV) and to reduce the design complexity of the controller , no steady-state error tracking control system was designed so that the contol system can meet the requirements of disturbance rejection and robust tracking. Using the no steady-state error tracking control strategy to the MASV, it can track reference signal perfectly. Its yaw angular velocity, sidesip angle and rolling angle are degraded at high vehicle speed. The stability and driving safety of the vehicle are improved. According to actual needs, the Parameter of the controller can be changed through the different characteristic value; The design and adjustment of the controller are simple amd easy.

Modelling Passive Yawing Motion of Horizontal Axis Small Wind Turbine: Derivation of New Simplified Equation for Maximum Yaw Rate

A large number of small wind turbines are installed in an urban area or on a rooftop where they experience sudden changes of wind speed and wind direction. For small wind turbines, the yawing load is one of the important design drivers because of its severity. Typically, a passive yaw system using a tail fin is employed for these small wind turbines. IEC61400-2 ed.2 provides a simplified equation for the maximum yaw angular velocity, or yaw rate, for use in estimating the yawing load. However, it is unclear whether this yaw rate considers the sudden change of wind direction. Furthermore, this simplified equation of yaw rate is only function of a rotor radius. In this paper, in order to consider the sudden change of wind direction, the authors derived the theoretical equation of the yawing motion to calculate yaw rate up to yaw angle of 180 degrees. This equation embraces the design variables including rotor radius, design tip speed ratio, tail fin area, and moment of inertia about the yaw axis. This theoretical equation was verified by comparing with wind tunnel test results. A number of theoretical calculations were undertaken varying all the design variables to find the relationship between the design variables and the yaw rate. Then, a new simplified equation, to calculate the yaw rate for a small wind turbine with a passive yaw system, is derived. This simplified equation is more practical than the existing IEC standard because it includes all design variables. This new equation enables to the yawing load to be estimated even for large change of wind direction.

Research on Active Yaw Mechanism of Small Wind Turbines

This paper presents the development process of an active yaw mechanism for small wind turbine with a power of 5kw or more, which contributes to avoid wind turbines turning frequently. In this mechanism, roller bearings make a revolute joint, a DC-motor provides power for yawing and combines a self-locking worm and a reducer to give system a big transmission ratio, which give this mechanism a low yaw angular velocity and make it yaw steady and accurately. This paper is of guiding significant to improve yaw stability and accuracy, extend the working life and enhance the wind power generation efficiency.

Signal Decomposition for Three-Axis Gyroscope

Study Algorithm of roll, pitch and yaw angular velocity for three-axis gyroscope. the gyro have only one sensitive quality, can sensitize the three axial angular velocity of the rotating carrier at the same time. in the case of gyro’s spin angular velocity presence and pitch or yaw angular velocity worked, gyro output signal contain spin, pitch and yaw angular velocity. Through Uniaxial Gravity Accelerometer’s application, the roll, pitch and yaw angular velocity for three-axis gyroscope can be demodulated.

Simulation Analysis of Wheeled Vehicle Skid-Steer

In this paper, the wheeled vehicle is regard as a multi-rigid-body system and simulation model of the vehicle is established firstly by using dynamics simulation software of mechanical system ADAMS which is used most widely in the world. Secondly, through setting the initial condition and inputting various parameters, simulation analysis of skid-steer during the unilateral braking process and swerving braking process that the vehicle runs roundly in constant speed of 10km/h and 20km/h respectively is performed. In addition, vehicle velocity curves are recorded, vehicle yaw angular velocity curve are showed, Side accelerated speed curve is seen, the turning track curve of centre is drawn and the results are contrasted. Finally, some conclusions are reached that the vehicle minimum turning track radius decrease immensely than the radius which does not adopt unilateral braking and vehicle velocity could be controlled in a small velocity rage when vehicle is steering braking.

Self-tuning Control on Integrated System of EPS and SAS Based on Pole Placement

Entire vehicle multi-degree of freedom dynamic model of Semi-Active Suspension(SAS) and Electric Power Steering(EPS) integrated system including yaw, roll and pitching motion is established. Self-tuning integrated control strategy of SAS and EPS integrated system based on pole placement is designed, and approach of on-line identification which combines the pole placement method with least square parameter estimation method is constructed. To carry out the real-time control on system, based on the simulation calculation, the developed adjustable shock absorber and integrated system controller are installed in a certain mini car. Real vehicle road test is carried on, and the simulation results are in good agreement with the test ones. Moreover, under self-tuning integrated control based on pole placement, the peak value and standard deviation of vertical acceleration of centroid, roll angle of vehicle body, pitching angle, yaw angular velocity, side angle of centroid are then reduced, vehicle ride comfort, handling stability and attitude change of vehicle body are improved, entire vehicle overall performance is enhanced.

A Combination of Silicon Micro-gyroscope that Application Rotary Missile Attitude Control System

For the technical requirements of rotary missile attitude control, there developed a new type of combination of silicon micro-gyroscope, it mainly consists of two perpendicular installation of micro-mechanical pendulum and the circuit. This paper reports this kind of combination of silicon micro-gyroscope, which attitude control system in polar coordinate transformation, the combination can demodulate the horizontal angular velocity, yaw angular velocity, pitch angular velocity and the spin angular velocity of the rotary missile. This combination of silicon microgyroscope have been tested in rotary missile, the results show that it works very well in rotating missile attitude control system.

Estimation of vehicle sideslip, tire force and wheel cornering stiffness

This paper presents a process for the estimation of tire–road forces, vehicle sideslip angle and wheel cornering stiffness. The method uses measurements (yaw rate, longitudinal/lateral accelerations, steering angle and angular wheel velocities) only from sensors which can be integrated or have already been integrated in modern cars. The estimation process is based on two blocks in series: the first block contains a sliding-mode observer whose principal role is to calculate tire–road forces, while in the second block an extended Kalman filter estimates sideslip angle and cornering stiffness. More specifically, this study proposes an adaptive tire-force model that takes variations in road friction into account. The paper also presents a study of convergence for the sliding-mode observer. The estimation process was applied and compared to real experimental data, in particular wheel force measurements. The vehicle mass is assumed to be known. Experimental results show the accuracy and potential of the estimation process.

Yaw Behavior of Horizontal-Axis Small Wind Turbines in an Urban Area

This paper reports the experimental study on passive yaw behavior of a horizontal axis small wind turbines. The yaw angle velocity in a small wind turbine is one of the significant design values and IEC61400-2 Ed.2 prescribes its maximum value should be less than 3 rad/s. However, in practice, in the case of small wind turbines with diameters under 2 m, the yaw angular velocity may exceed the limit of 3 rad/s. The authors conducted a theoretical evaluation as well as a wind tunnel test to examine the possible maximum yaw velocity. The model wind turbine has a diameter of 1 m, blade number of 5, solidity of 0.26 and 2 types of tail fins (large and small). For each tail fin size, the yaw behavior was studied for a range of rotational speeds and wind speeds. The results show that the yaw angular velocity becomes larger with increasing wind velocity and tail fin area. The larger the rotor rotational speed, the smaller the yaw angular velocity. Furthermore, a maximum yaw angular velocity of 3.84 rad/s was observed at a wind speed of 10 m/s, which exceeds the conventional design value of 3 rad/s.

Grey box-based inverse wagon model to predict wheel–rail contact forces from measured wagon body responses

A grey box-based inverse wagon model was developed to estimate wheel–rail contact forces using only measurements of wagon body responses as inputs. The project is based on a similar application using a deterministic inverse wagon model [F. Xia, C. Cole, and P. Wolfs, An inverse railway wagon model and its applications, Veh. Syst. Dyn. 45 (6) (2007), pp. 583–605]. The deterministic (i.e. white box) inverse wagon model has some limitations, one of which is that the high-frequency components of the forces at the wheel–rail interface cannot be predicted from the lower frequencies at the wagon body. They are effectively isolated by the suspension. To overcome this problem, the present research focuses on developing of a grey box-based inverse wagon. The high-frequency forces may be considered as the responses to random track irregularities with high frequency and appear as a random feature. The grey box-based inverse wagon is used to predict wheel–rail contact forces using only lateral and vertical accelerations, roll, pitch and yaw angular velocities measured on the wagon body.