8results about How to "Control error" patented technology

This invention discloses a three-dimensional assembly method for ultra-large span double-layer steel truss bridges, including: setting two rows of steel piers according to the camber of the jig and preventing settlement; using a gantry crane with special clamps to achieve the horizontal and vertical conversion of the truss segments; assembling the first segment in the order of lower bridge deck, side trusses, and upper bridge deck; subsequently, matching and welding the mother segments in the same order; pre-setting vertical anti-deformation during assembly, and welding from the middle section to both sides; uniformly installing anchor pipes after the completion of the large segment assembly in a single round; setting three quality control points during assembly to check the total length, side curvature, truss width, diagonal difference, camber, and anchor point spacing; after passing the test, disassembling and removing the jig, retaining the mother segment for the next round. This application controls welding deformation and cumulative alignment error through multi-segment continuous matching assembly and anti-deformation pre-setting; the subsequent installation of anchor pipes avoids collisions and ensures anchor point accuracy; setting the jig according to the camber and re-measuring in rounds achieves a reliable transition from stress-free to stress-loaded installation.

The application provides a soil dry-wet cycle device with hydrodynamic pressure regulation function and a test method, wherein the soil dry-wet cycle device comprises a test table, a support, a water pump, a water storage tank and an automatic dry-wet cycle mechanism, the automatic dry-wet cycle mechanism comprises a sealing top cover, a dry-wet cycle chamber, a dryer, a soil sample mounting unit and a controller, the soil sample mounting unit comprises a fixing structure, a microporous diaphragm bottom plate, a soil ring knife positioning sleeve frame and a microporous diaphragm top plate, the microporous diaphragm top plate and the microporous diaphragm bottom plate both have water-permeable and air-permeable structures, a first electromagnetic valve is installed on a water inlet pipe, a second electromagnetic valve is installed on a lower drain pipe, dryers are fixedly arranged at air inlets, and the controller is connected with the water pump, the dryers, the first electromagnetic valve and the second electromagnetic valve; and the application further provides a test method. The application can realize automatic quantitative research on the influence of dry-wet cycles on soil characteristics under different conditions in large quantities, and can also research the influence of different ions on soil characteristics in dry-wet cycles.

The invention particularly relates to a B spline curve offset-selfing elimination method based on Legendre polynomial expansion. The method comprises the following steps of: obtaining a Legendre coefficient auxiliary matrix on the basis of a Legendre polynomial value and a Gauss-Legendre quadrature node weight; the method comprises the following steps: mapping a Gauss-Legendre quadrature node to a non-zero length node interval to obtain a corresponding normal direction; acquiring a corresponding offset point according to the normal direction and the specified distance; based on the Legendre coefficient auxiliary matrix and the offset point, obtaining a Legendre coefficient; compared with a Taylor expansion method, the Legendre orthogonal basis expansion method has the advantages that the approximation convergence rate is better; and the error can be further controlled through calculation of the truncation error of the Legendre coefficient and subsequent judgment and processing. The Legendre coefficient auxiliary matrix and the Legendre-Bezier transformation matrix are pre-calculated static data, so that global repeated calling for multiple times can be realized, and the approximation efficiency is improved. And when the tangent intersection detection triggered by the adjoint matrix eigenvalue method fails, returning is executed, and real intersection and tangent intersection are distinguished based on a GCD decomposition method, so that the selfing detection efficiency is further improved.

The utility model discloses a concrete aggregate automatic metering and batching device, and belongs to the technical field of concrete production, the concrete aggregate automatic metering and batching device comprises a rack, a conveying belt is rotatably connected in the rack, fixing frames are arranged on the two sides of the rack, a transverse frame is arranged between the two fixing frames, and a plurality of aggregate storage hoppers are arranged in the transverse frame; a gate weighing mechanism is arranged at the bottom of the aggregate storage hopper and comprises a fixing plate, the fixing plate is located on one side of the aggregate storage hopper, a gate is rotationally connected to the middle of the fixing plate, a weighing module is arranged above the gate, and the gate abuts against the bottom of the aggregate storage hopper; when the device is used, the aggregate batching error can be effectively controlled, and the concrete strength consistency can be remarkably improved; the production efficiency is further improved, meanwhile, the automation level can be improved, and manual intervention is effectively reduced; the system is low in use cost and suitable for small and medium-sized mixing stations.

The application discloses a cantilever type instrument operation parameter optimization trajectory planning method for a multi-constraint field coupling in a limited space, and relates to the technical field of dental robots. In the tooth preparation process, the instrument is prone to collision with the tooth and oral tissue in the limited space in the oral cavity, and the end force deformation affects the machining precision. The technical points are as follows: the residual volume of the interaction between the bur and the tooth is calculated, and an end force deformation model based on grinding force, friction force and extrusion force is established; a penalty function containing the collision between the bur and the tooth, the collision between the handle of the dental handpiece and the mouth and the tooth is constructed, and the space collision detection is carried out through the enclosing ellipsoid method; in combination with the continuity requirement of the joint angle, an optimization function taking the material residual volume, the comprehensive deviation of the end deformation and the motion smoothness as targets is established, and a multi-objective optimization algorithm is adopted to solve the optimal instrument pose and joint parameters; and the operation parameters of the cantilever type instrument under multiple constraints are optimized under the premise of ensuring the preparation accuracy and safety.

This invention relates to the field of water conservancy engineering technology, specifically to a method for monitoring suspended sediment in the Yellow River Estuary and its adjacent sea areas based on multi-source remote sensing data. The method includes the following steps: selecting complementary multi-source remote sensing data (Landsat 8 OLI, Sentinel-2A / B, GF-1 WFV, GOCI), and performing radiometric calibration, atmospheric correction, and geometric fine correction standardization preprocessing; using an algorithm combining weighted average and principal component analysis to fuse the multi-source data and extract sediment-sensitive characteristic information; constructing an improved semi-empirical radiative transfer model incorporating tidal current, wind speed, and hydrodynamic correction factors to invert suspended sediment concentration, and ensuring the reliability of the results through multi-dimensional verification. This invention significantly improves monitoring accuracy and spatiotemporal coverage, and is adaptable to routine, emergency, and long-term dynamic monitoring of the Yellow River Estuary, providing scientific support for estuary ecological protection and management decisions.

The utility model discloses a pipeline elbow angle measuring tool, which comprises a fixed platform and an angle measuring assembly, a supporting part is vertically arranged on the fixed platform, the angle measuring assembly is positioned above the fixed platform, and the angle measuring assembly comprises a fixed part, a movable part and a measuring part, the fixed part is connected with the supporting part, the two opposite ends of the movable part are rotationally connected with the fixed part and the measuring part respectively, and a protractor and a gradienter are arranged on the measuring part. According to the pipeline elbow angle measuring tool, elbow inspection efficiency and accuracy can be improved, deformation and errors in the elbow welding process can be effectively controlled, production efficiency and product quality are improved, and meanwhile working efficiency is improved.

The invention discloses an external clamping type liquid ultrasonic flowmeter integrated with a scanning imaging detection technology, and relates to the technical field of liquid flow measurement and pipeline safety detection, the external clamping type liquid ultrasonic flowmeter comprises an external clamping type sensing main body and a detection system, and the external clamping type sensing main body is of a detachable clamping structure; the detection system comprises an ultrasonic transmitting and receiving module, a scanning imaging module, a signal processing module, a data storage and analysis module and a wall thickness compensation module. The ultrasonic transmitting and receiving module is used for controlling an ultrasonic transducer array integrated in the outer clamping type sensing main body to periodically transmit ultrasonic signals, synchronously receiving ultrasonic echo signals reflected and transmitted by a pipeline wall and a liquid medium, and sending the ultrasonic echo signals to the scanning imaging module; the ultrasonic flow measurement and the pipeline scanning imaging detection technology are fused, integration of flow measurement and corrosion detection can be achieved, function integration is further achieved, multiple devices do not need to be used independently, the detection cost is reduced, and the detection efficiency is improved.