Operation safety evaluation method and system of railway freight vehicle,Photoetching machine worktable with driving device capable of balancing torque,Method of facilitating the approach to a platform,Reticle stage balance block combined centroid anti-drifting movement control method

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In mathematics and physics, the centroid or geometric center of a plane figure is the arithmetic mean position of all the points in the figure. Informally, it is the point at which a cutout of the shape could be perfectly balanced on the tip of a pin.

Operation safety evaluation method and system of railway freight vehicle

ActiveCN109712270AAccurate and effective assessmentRegistering/indicating working of vehiclesSafety indexDynamic models

The invention discloses an operation safety evaluation method and system of a railway freight vehicle. According to the method, a mass, a centroid position and a rotary inertia parameter of a vehiclebody loaded with cargos are calculated based on data collected by a data acquisition device; the mass, the centroid position and the rotary inertia parameter of the vehicle body loaded with cargos areinputted into a vehicle-track coupling dynamics model as dynamic parameters; a required wheel-rail contact force is calculated by combining the running condition of the vehicle; a derailment coefficient, an overturning coefficient and a wheel load shedding rate of the vehicle are respectively calculated; and then whether the derailment coefficient, the overturning coefficient and the wheel load shedding rate meet corresponding safety conditions is determined to determine whether the safety index of the vehicle is qualified. Therefore, because of consideration of the characteristic of the loaddiscrete distribution of the railway freight vehicle, the running safety state of the railway freight vehicle can be evaluated accurately and effectively, so that the risk of overturning and derailment of the railway freight vehicle is reduced.

Owner:SOUTHWEST JIAOTONG UNIV +1

Photoetching machine worktable with driving device capable of balancing torque

ActiveCN102012638ABalance disturbancePhotomechanical exposure apparatusMicrolithography exposure apparatusElectric machineEngineering

The invention provides a photoetching machine worktable with a driving device capable of balancing torque, comprising a coarse motion part and an inching part. The coarse motion part comprises an X-direction part and a Y-direction part which is arranged at the bottom of the X-direction part, the X-direction coarse motion part is provided with an X-direction driving motor and an X-direction comprehension motor, and the Y-direction coarse motion part is provided with a Y-direction driving motor. The photoetching machine worktable with the driving device capable of balancing the torque, which is proposed by the invention, adopts a motor as a main driving motor of the worktable and another motor to be in parallel with the former motor so as to eliminate additional torque, i.e. the two motors are combined to eliminate the additional torque which is generated by the driving force and the centroid mismatching of the motors.

Photoetching machine worktable with driving device capable of balancing torque

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Owner:SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD +1

Method of facilitating the approach to a platform

ActiveUS20150375871A1Convenience to workEasy to prepareAnalogue computers for vehiclesAircraft landing aidsEngineeringDecision taking

A method of facilitating the approach to a platform by an aircraft, the method comprising a step of constructing a database, including for each stored platform at least one identifier of the platform, coordinates of a geometrical center of the platform, a height of the geometrical center, and the radius (OR) of a circle in which the platform lies. During a parameter-setting step, the target platform to be reached, a course to be followed, and a height parameter relative to a minimum decision altitude are determined. During a path construction step, the positions of an initial approach fix (IAF), of a final approach fix (FAF), and of a decision point (MAP) are determined by placing them in a plane that is offset relative to the platform.

Owner:EUROCOPTER

Reticle stage balance block combined centroid anti-drifting movement control method

ActiveCN105676597AEliminate the effects ofDrift does not occurPhotomechanical exposure apparatusMicrolithography exposure apparatusRelative displacementMovement control

The invention relates to a reticle stage balance block combined centroid anti-drifting movement control method. The method comprises the steps that a relative displacement signal of a balance block relative to the y direction of a base station and a relative displacement signal of a coarse moving station relative to the y direction of the balance block are obtained respectively by adopting absolute grating rulers; a balance block and coarse moving station combined centroid displacement signal is obtained by calculating the displacement signals and serves as a feedback signal, nonlinear variable gain anti-drifting control is conducted on the balance block, and therefore the combined centroid position remains unchanged. According to the reticle stage balance block combined centroid anti-drifting movement control method, the influence of reactive force of a coarse moving station linear motor on the base station can be effectively eliminated, the combined centroid anti-drifting movement control method not only can ensure the balance block not to produce drifting exceeding the limit range in the coarse moving station linear motor moving process, but also can prevent larger reactive force from being transferred to the base station.