107results about How to "Eliminate cumulative errors" patented technology

The invention discloses a park sweeper positioning and environment mapping method based on multi-sensor fusion. The method comprises the following steps: S1, preprocessing multi-modal data acquired by a plurality of sensors; s2, extracting and fusing semantic features and geometric features in the multi-modal data preprocessed by the plurality of sensors; s3, performing geometric feature extraction and recognition on the point cloud data by using a VoxelNet point cloud processing algorithm; s4, performing pose estimation and track plotting by fusing multi-sensor data; s5, identifying places where the motor sweeper repeatedly passes through through loopback detection, and correcting accumulated errors; and S6, constructing a three-dimensional environment map by fusing the laser radar, the visual features and the IMU data, performing global optimization by applying a map optimization technology, correcting errors, improving map precision, and updating the map in real time. According to the invention, the autonomous navigation capability of the sweeper is enhanced, the sweeping efficiency and safety are improved, and the sweeper is suitable for various complex and dynamic park environments.

The invention discloses a robot vision inertial navigation method and device and a storage medium, and belongs to the technical field of mobile robot navigation, and the navigation method comprises the following steps: measuring motion information of a mobile robot by using an IMU sensor; collecting image data of the mobile robot by using a camera; inputting the feature points and the descriptors into a LightGlue network model to obtain a local feature point matching relation of the image; calibrating the offset of the gyroscope by optimizing and recovering visual scale information, and estimating the IMU coordinate system speed, the gravitational acceleration and the offset of the IMU; introducing a visual feature re-projection error, an IMU pre-integration error and marginalized residual constraint, and then integrally converting into a target function to obtain a nonlinear optimization result; further repositioning is carried out to obtain a repositioning result; and optimizing the global pose map to obtain a final global pose map optimization result, and carrying out navigation operation according to the global pose map optimization result. The method can improve the positioning precision and operation efficiency under view angle change and illumination change, and is high in practicality.

This invention provides a method for rapid assembly of a modular tubular beam car body. The car body is divided into several independent modules, which are manufactured in parallel at independent workstations or assembly lines. Corresponding connections between different independent modules are fitted with interlocking mortise and tenon structures for coarse positioning and fastening. The manufactured independent modules are then automatically transferred to an assembly station, where a robot grasps and rapidly assembles them. After assembly, bolts and / or structural adhesive are used to fasten the mortise and tenon joints. Compared to traditional assembly line production processes, this method significantly improves efficiency and economy, effectively reduces floor space, and overcomes the limitation of existing "unpacking processes" that are only suitable for single-model production, thus facilitating flexible manufacturing and rapid iteration across multiple models.

The present invention discloses a laser radar positioning method based on ICP and KD tree, and relates to the field of navigation and positioning technology. A mobile terminal equipped with a laser radar is used to scan each fixed target object in a target area, and a point cloud set corresponding to each fixed target object is obtained. The point cloud set includes a continuous point cloud of a reflector and a continuous point cloud of a wall. For each fixed target object in the target area, based on the reflection intensity of each single point cloud in a single point cloud frame, the coordinates of the fixed target object are extracted and the position and posture of the mobile terminal equipped with the laser radar are determined using the ICP algorithm. Through the technical solution of the present invention, initial values ​​are provided for the ICP algorithm and the KD tree search, which improves the real-time performance and robustness, and removes the accumulated error.

The invention discloses a method and device for controlling vehicle driving, a vehicle and a storage medium. The method comprises the steps of obtaining the speed of a vehicle; gradient information is obtained, wherein the gradient information represents the inclination degree of the ground where the vehicle runs currently; based on the speed and gradient information of the vehicle, a control result is determined, the control result indicates whether an integral term in a specified calculation formula is cleared or not, the specified calculation formula is a calculation formula adopted when the PID control algorithm is adopted for carrying out driving control on the vehicle, and the integral term represents an accumulative error generated when the PID control algorithm is adopted for carrying out driving control on the vehicle; and controlling vehicle driving based on the control result. According to the technical scheme provided by the embodiment of the invention, when the gradient information of the current driving ground of the vehicle changes and the acceleration process needs to be ended, the accumulated error can be eliminated, the situation that the acceleration process of the vehicle cannot be ended in time is avoided, excessive overshoot of the vehicle speed is avoided, and thus the riding experience of a user is improved.

The utility model discloses a positioning mechanism which comprises a base, a linkage assembly, a driving assembly and a plurality of positioning assemblies, the base comprises a bottom seat and a top seat which are connected with each other and form a cavity, and a plurality of bearing parts and bearing positions in one-to-one correspondence with the positioning assemblies are distributed on the top seat; the linkage assembly comprises a linkage piece which is contained in the cavity and elastically floats between the base and the top base. The driving assembly comprises an eccentric part which is rotationally arranged on the top seat in a penetrating mode and eccentrically abuts against the linkage part; each positioning assembly comprises a positioning seat which is accommodated in the cavity and is adjacent to the corresponding bearing position, and a first positioning piece and a second positioning piece which are slidably and elastically connected to the positioning seat; and the linkage piece elastically floats so as to drive the first positioning piece and the second positioning piece to be close to the corresponding bearing positions respectively through matching and abutting between the linkage piece and the inclined surfaces of the first positioning piece and the second positioning piece, so that the parts are tightly pressed on the corresponding bearing positions. According to the positioning mechanism, the flexible clamping part is positioned, the collision and scratching conditions of the part are reduced, and the welding yield is increased.

The invention relates to the technical field of anti-deception navigation, and discloses a dynamic anti-deception navigation method and system for an unmanned aerial vehicle, and the method comprises the steps: obtaining a signal of a satellite navigation system in the flight process of the unmanned aerial vehicle, and detecting and identifying a potential interference signal; adjusting filter parameters in real time according to the motion state of the unmanned aerial vehicle, and filtering noise and jump signals; when the signal of the satellite navigation system is seriously interfered, the signal of the satellite navigation system and the data of the inertial measurement unit are subjected to data fusion, short-time navigation of the unmanned aerial vehicle is maintained, and dynamic anti-interference deception of the unmanned aerial vehicle is realized. According to the method, interference and deception signals can be accurately identified and filtered by adopting multi-dimensional signal detection and analysis of multi-frequency multi-antenna receiving, time propagation error, power estimation, pseudo-range consistency and the like. When satellite navigation signals are seriously interfered, short-time navigation is carried out through IMU data, and it is ensured that the unmanned aerial vehicle keeps flight stability and navigation continuity in a complex environment.

The invention discloses a multi-source fusion continuous positioning method in combination with a prior feature map, and aims to solve the problem that an existing vision-inertial odometer easily generates accumulative errors in a GNSS denial environment, the method comprises the following steps: constructing a prior feature map comprising key frame poses, feature point descriptors and 3D coordinates based on an open source algorithm; a track displacement difference alignment strategy is adopted to complete visual-inertial system and GNSS joint initialization, and ESIKF is used to replace EKF to improve fusion precision; robust alignment of a local coordinate system and a map coordinate system is achieved through a single-frame geometric constraint accumulation-batch manifold alignment strategy; based on the reverse PnP, the current 3D point cloud and the historical 2D observation constraint are utilized to resolve the relative pose, the map matching result is used as observation to be fused with the GNSS or replace GNSS observation, the ESIKF loose coupling is utilized to eliminate accumulative errors, and continuous high-precision positioning in the GNSS failure scene is achieved.

The present invention discloses an I frame rate control method suitable for hardware implementation. A plurality of intra-frame coding modes are used for preliminary screening of each image block to be encoded, and intra-frame coding mode candidates and their corresponding intra-frame coding mode prediction costs are screened. The intra-frame coding mode prediction cost corresponding to each intra-frame coding mode candidate of the image block to be encoded is screened, and the minimum intra-frame coding mode prediction cost is selected to characterize the intra-frame coding complexity of the image block to be encoded; then the sum of the intra-frame coding complexities of all image blocks in the video frame is taken as the intra-frame coding complexity of the video frame. According to the actual number of coding bits, frame-level Lagrangian multipliers and intra-frame coding complexity of the previous encoded I frame, combined with the target number of coding bits and intra-frame coding complexity of the I frame to be encoded, the frame-level Lagrangian multipliers of the I frame to be encoded are calculated. The present invention has high calculation accuracy, low hardware overhead and low implementation cost.

The invention relates to the technical field of water conservancy project automation control, and discloses a water conservancy facility operation state monitoring system based on digital twinning, and the system comprises a data collection unit which is used for collecting a basic control instruction and an actual measurement state response of an execution mechanism in real time; the generalized impedance observation unit is used for calculating the state deviation between the actually measured state response and the theoretical reference trajectory and mapping the state deviation into an equivalent disturbance quantity; the track time base modulation unit is used for establishing a load-time base association rule of the equivalent disturbance quantity and the time scaling factor; the nominal model simulation unit is used for generating a theoretical reference trajectory under the constraint of a time scaling factor, the generation rate of the theoretical reference trajectory is actively reduced through a load time base association rule when it is detected that the system resistance is increased, and the safety space of an execution mechanism is replaced by time; and the contradiction between the execution capability decline of the aged water conservancy facility and the rigid control target is solved.

The application discloses a reflection type volume grating uniformity improving device and method, which adopts a double-system cooperative structure of axial exposure dose compensation and double-beam interference exposure. The axial exposure dose compensation system compensates the non-uniform axial exposure dose distribution caused by energy attenuation through laser irradiation of a photosensitive wave band of a recording medium and multi-axis rotation of the recording medium. The double-beam interference exposure system generates two collimated coherent lights with adjustable polarization states and powers by using laser of a high-transmittance wave band of the recording medium and a polarized beam splitter, and accurately controls the interference angle by adjusting the mirror posture, so that the high-contrast grating structure is written in the recording medium subjected to the axial exposure dose compensation. The application can effectively solve the non-uniform exposure dose distribution problem caused by laser energy attenuation in the traditional preparation process, thereby guaranteeing the consistency of the axial performance of the volume grating, and effectively promoting the development of the fields of high-performance laser beam combination, pulse compression and optical communication filter which need high-uniformity volume grating.

This utility model provides a modular tooling fixture mechanism for machining triple eccentric butterfly valve bodies, belonging to the technical field of fixture mechanisms. This modular tooling fixture mechanism for machining triple eccentric butterfly valve bodies includes a floating clamping module and a quick-change flange positioning base plate. The floating clamping module is disposed above the quick-change flange positioning base plate and is used to float and clamp the triple eccentric butterfly valve body placed on the quick-change flange positioning base plate. The quick-change flange positioning base plate is used to position the triple eccentric butterfly valve body and realize overall transfer between multiple processes. The floating clamping module includes a main frame and a pneumatic auxiliary locking assembly. The main frame adopts a three-way eccentric adjustment mechanism, which has a built-in adjustable wedge block, and the adjustable wedge block is connected to a screw. This solves the problems of eccentric deformation, cumulative positioning errors in multiple processes, and poor tooling versatility in the machining of triple eccentric butterfly valve bodies, eliminates repeated clamping errors, and improves accuracy and efficiency.

The invention relates to an arrow optimization modeling method and device, and the method comprises the steps: reconstructing an arrow model according to a constraint relation between objects, carrying out large-scale nonlinear optimization, and adjusting a pose to eliminate an accumulative error in a system, and improving the modeling precision of an arrow under an SLAM system; the object comprises a characteristic line and / or an arrow; the constraint relation comprises plane constraint between the characteristic lines and the arrows, parallel vertical constraint between the characteristic lines or coplanar constraint between the arrows, and the device is used for realizing the method. Compared with the prior art, the method has the advantages of higher mapping accuracy and the like.

The application discloses a kind of coronary angiography three-dimensional reconstruction method and system, it is related to medical image processing technical field, including: obtaining multi-angle coronary DSA angiography projection image and executing pre-processing, extract blood vessel initial center line and both sides initial contour, calculate each section contrast agent relative concentration, combined with blood vessel local curvature, concentration difference sign change and anatomical feature adaptive segmentation blood vessel section, filter reliable reference side and generate mirror virtual contour, calculate three kinds of contour deviation, construct multi-constraint objective function and correct center line section by section, integrate corrected center line and fit lumen parameter, solve blood vessel feature point three-dimensional coordinate and complete three-dimensional reconstruction.The application has the advantages that: effectively suppress the center line deviation caused by contrast agent concentration uneven, consider correction accuracy and blood vessel form continuity, the size of three-dimensional model output is accurate, topological correct, can be directly used for clinical quantitative diagnosis and interventional operation planning.

This invention discloses an automatic cutting, folding, and grouping machine, comprising a longitudinal folding mechanism, a hole-cutting mechanism, an edge-trimming mechanism, a cutting and folding mechanism, and a grouping mechanism through which the mother roll passes in sequence. The longitudinal folding mechanism is used to fold and press the mother roll along its length; the hole-cutting mechanism is used to cut and form eyelets and collect the waste material after cutting; the edge-trimming mechanism is used to cut and form mouth holes; the cutting and folding mechanism is used to cut the mother roll into multiple sheet-like units and fold the sheet-like units along their width; the grouping mechanism is used to group and stack multiple sheet-like units in a fixed number; the hole-cutting process integrates an automatic waste collection system of negative pressure adsorption and positive pressure blowing, which can remove cutting waste material in a timely and effective manner; the integrated cutting and folding design, through the synergistic effect of pre-folding and adsorption transfer, eliminates the cumulative error of multi-process positioning, significantly improving folding accuracy and product neatness; the fully automatic fixed-number grouping and stacking mechanism achieves precise grouping through mechanical timing control.

This invention relates to the field of intelligent warehouse management technology, specifically an intelligent warehouse cargo identification and inventory system. The system synchronously collects multi-dimensional signals caused by cargo removal or replenishment actions through a multi-dimensional sensing unit; extracts signal feature components representing the current cargo removal or replenishment action from each dimension signal, and merges them to form a multi-dimensional joint signal feature vector; pre-establishes an indirect sensing mapping model for deeply obscured storage locations; inputs the multi-dimensional joint signal feature vector into the indirect sensing mapping model, outputs a joint posterior probability distribution of the change in cargo quantity in the target deeply obscured storage location, obtains the cargo quantity change with the highest probability in the joint posterior probability distribution and the corresponding target deeply obscured storage location, and updates the baseline inventory data of the target deeply obscured storage location in real time to form inventory change details; thus achieving real-time identification of cargo quantity changes in deeply obscured storage locations and dynamic and accurate updating of inventory data.

This invention discloses a wide-width defect detection system and operating method for sandpaper preparation, relating to the technical field. The invention includes a base plate, with a mounting frame fixedly connected to the top center of the base plate. A marking mechanism is provided on the right side of the mounting frame, and an air blowing mechanism is provided on the mounting frame. The invention uses a first motor to drive a first lead screw, moving the moving frame to the lateral position of the defect. Subsequently, a second motor drives a second lead screw, precisely moving the first moving seat directly above the defect for secondary confirmation by a secondary camera. During this process, the first and second moving seats are rigidly connected via a connecting rod. Therefore, when the first moving seat is positioned directly above the defect, the second moving seat is naturally and synchronously positioned directly below the defect, without the need for additional coordinate conversion or secondary positioning. This rigid connection structure ensures that the position of the punch assembly and the center of the secondary camera's field of view always maintain a strict vertical correspondence, achieving the goal of marking exactly what is captured.

This utility model discloses a mechanical push-pull digital display clock device, belonging to the field of electronic clock technology. It includes a time acquisition module, a control module, a drive execution unit, and a segmented mechanical display unit. It aims to solve the problems of existing electronic clocks having a single display form, insufficient positioning accuracy, and limited functionality. The core innovations are: 1. Push-pull segmented display: The drive execution unit (stepper motor + crank / electromagnetic component) controls the protrusion / retraction of multiple rigid telescopic segments, dynamically combining them into a digital display; 2. Closed-loop calibration mechanism: The position calibration module establishes a zero-position reference for the telescopic segments during initialization; 3. Universal control architecture: It does not rely on specific hardware models and covers both mechanical transmission and electromagnetic drive schemes. It solves the problems of traditional electronic clocks lacking mechanical interactivity and having low precision, breaking through traditional display forms and combining creative decoration with practical functionality. It is suitable for artistic time display scenarios, smart homes, creative decorations, electronic teaching, public spaces, and barrier-free facilities.

The application discloses a joint control method and system of multiple servo motors, which comprises the following steps: collecting real-time working parameters, load feedback data and target feature information of multiple servo motors, and performing space-time alignment and noise filtering processing, simultaneously extracting dynamic response parameters corresponding to each servo motor, and determining the load coupling coefficients between the servo motors; constructing a collaborative task matrix and generating an initial collaborative control strategy; determining different working process stages corresponding to the multiple servo motors, calculating the corresponding collaborative priority weights, and constructing a phased collaborative control model; obtaining corresponding working state parameters and the current state of the target, dynamically adjusting the collaborative coefficients corresponding to each servo motor, substituting into the phased collaborative control model to generate real-time control instructions corresponding to each servo motor, and performing joint control iterative optimization to generate a closed-loop adaptive joint control mechanism. The application can improve the joint control efficiency of multiple servo motors.

The invention provides a milling assembly for a generator rotor processing machine tool, and relates to the technical field of generator rotor processing equipment, the milling assembly comprises a rotating disc, the middle part of the rotating disc is provided with an axis hole connected with a power shaft of the generator rotor processing machine tool, and the peripheral surface of the rotating disc is provided with a plurality of assembling grooves; the multiple machining cutter sets are sequentially arranged in the circumferential direction of the rotating disc, each machining cutter set comprises a grooving cutter clamp, a fillet cutter clamp and a polishing cutter clamp which are sequentially arranged, and the grooving cutter clamps, the fillet cutter clamps and the polishing cutter clamps are all detachably installed in the assembling grooves; and the machining cutter set is made to sequentially conduct grooving, notch chamfering and grinding on the engine rotor along with rotation of the rotating disc. According to the milling assembly for the generator rotor machining tool, the core problems that the machining process is tedious, the efficiency is low, and the precision is out of control due to multiple times of clamping are solved.

The utility model discloses a kind of multi-axis layered linkage blade lever for small circuit breaker, comprising: lever body, it is the special-shaped plate member of integrated molding;Main pivot hole, the lever body can rotate around the main pivot hole;First lateral transmission column, for cooperating with circuit breaker handle or superior linkage member;Second lateral transmission column, set in the middle pivot area;Third lateral transmission column;Wherein, the first lateral transmission column, the second lateral transmission column and the third lateral transmission column are layered arrangement along the lever body height direction, and form stepped overhanging structure in the lever body thickness direction, so that handle linkage member, blade driving member and spring energy storage member can be respectively located in different movement level.This multi-axis layered linkage blade lever for small circuit breaker integrates multiple components on a special-shaped plate lever body, with the characteristics of high part integration, good assembly precision and small movement interference.

The invention relates to the technical field of vehicle navigation, and discloses an airborne closed cabin vehicle path dynamic navigation planning method, which comprises the following steps: S1, navigation initialization, S2, real-time perception data acquisition and correction, and upward navigation reference based on a target established in the step S1, S3, map-free error correction and fusion, S4, dynamic path planning, and S5, accurate correction before landing. And S6, outputting a navigation control instruction based on the real-time navigation track in the step S4. Complete autonomous navigation of an airborne closed cabin vehicle in the whole process is achieved, dependence on external visual reference, a pre-built map or a ground guide signal is not needed, an absolute direction anchor point is provided through a target upward navigation benchmark, multi-source sensor decoupling correction and adaptive Kalman filtering fusion are combined, airflow disturbance compensation is synchronously brought in, and the navigation precision is improved. The inertial navigation accumulative error is effectively eliminated, the method can be adapted to an extreme airborne environment without reference, map and signal, and the independence and reliability of the navigation process are guaranteed.

The application discloses a long-distance tunnel control through-accuracy measurement and verification system, and relates to the technical field of tunnel construction measurement. The system comprises a measurement control point, an observation traverse, a traverse stake, a traverse measurement network, the observation traverse being arranged on the traverse stake, one end of the observation traverse being connected with the measurement control point, the other end of the observation traverse being connected with the traverse measurement network, a first ground control network; the system further comprises a pilot hole, a verification traverse, a through tunnel, a horizontal drill hole and a second ground control network; the structure of the second ground control network is the same as that of the first ground control network, the verification traverse is arranged in the pilot hole and along the length direction of the pilot hole, the verification traverse is installed on the traverse stake of the second ground control network, one end of the verification traverse is connected with the measurement control point of the second ground control network, and the other end of the verification traverse is connected with the traverse measurement network through the horizontal drill hole. The application has the effect of verifying the through-accuracy measurement result of the first ground control network.

This invention discloses an integrated intelligent grinding device for processing the inner and outer rings of deep groove ball bearings, relating to the field of grinding-related technologies. The device includes a frame fixed to a base, a top plate fixed to the frame, and a support cylinder. A connecting plate is fixed to the top of the support cylinder via a transmission rod. The connecting plate is mounted on the bottom of the top plate via a drive mechanism. Two synchronous rings are slidably mounted on the support cylinder, and two sets of grinding discs are fixed between the two synchronous rings. The two sets of synchronous rings are located on the inner and outer walls of the support cylinder, respectively. An adjustment mechanism is installed on the support cylinder, which drives the two grinding discs to move relative to each other, causing the grinding discs to deform and conform to the rolling tracks of the bearing's outer and inner rings. This allows for simultaneous grinding of five key surfaces—the outer wall of the bearing's outer ring, the inner wall of the bearing's inner ring, the rolling tracks of both rings, the top surface, and the bottom surface—in a single clamping operation, eliminating the cumulative errors caused by multiple clamping operations.

The application discloses a high-precision six-axis motion platform, which comprises a steel frame assembly, a stone material assembly, an XY-axis assembly, an AC-axis rotary table, a Z-axis assembly and a B-axis rotary table, the stone material assembly is installed on the steel frame assembly, the XY-axis assembly is installed on a base of the stone material assembly, the AC-axis rotary table is horizontally installed on a Y-axis load plate of the XY-axis assembly, the Z-axis assembly is vertically installed on a cross beam of the stone material assembly, and the B-axis rotary table is installed on a Z-axis load plate of the Z-axis assembly. The six-degree-of-freedom independent collaborative control is realized through the brand-new modular independent partition structure and the direct drive transmission-free scheme, the transmission gap and coupling error are eliminated from the mechanical root, the platform positioning precision, the dynamic response speed and the structural rigidity are simultaneously improved, the assembly and calibration process is simplified, the production and maintenance costs are reduced, and the high-precision operation of the semiconductor and optical detection fields is adapted to the harsh working conditions.

This utility model provides a three-head aluminum profile dual traction machine, relating to the technical field of aluminum traction equipment. It includes a transmission machine and three traction mechanisms, which are slidably connected to one side of the transmission machine. A roller conveyor belt is installed on the transmission machine. A main shaft box is located at the rear end of one side of the transmission machine, and three drive shafts extend from the main shaft box. Each drive shaft is connected to and installed with a traction mechanism at its end. The machine employs a mechanical linkage drive method using a planetary gear differential and a servo motor, enabling the three traction mechanisms to automatically adjust torque distribution during traction, eliminating accumulated errors caused by response delays or speed deviations in the electronic control system. Simultaneously, the design of the universal joint coupling and spline telescopic drive shaft ensures stable power transmission even when the traction mechanism moves on the slide rail, avoiding profile twisting or surface scratches caused by speed differences.

This utility model provides an oil channel support strip pressing device, which includes a conveyor belt, a winding machine, and a conveying mechanism. A pressure plate is transversely mounted on the conveyor belt, which transports insulating paperboard. The pressure plate is lifted and lowered on the conveyor belt to press the support strips onto the insulating paperboard. Two winding machines are located at opposite ends of the conveyor belt for unwinding and rewinding the insulating paperboard. The conveying mechanism is located at one end of the conveyor belt, on the side of the winding machine that outputs the insulating paperboard, and is used to place the support strips onto the insulating paperboard. This utility model's oil channel support strip pressing device, through its integrated design of continuous unwinding, feeding, and pressing, eliminates the cumulative errors caused by pauses, resulting in good consistency in the bonding position. The rigid system formed by the support frame and hydraulic cylinder ensures stable lifting of the pressure plate, uniform pressing force, and reduces bonding defects. Double-sided auxiliary rods guide and suppress pressure plate sway, preventing support strip displacement during the pressing process.

The invention relates to the technical field of detection of copper-steel composite materials, and discloses a method for detecting the mass ratio of coating metal in a copper-steel composite material. The method comprises the following steps: preparing the copper-steel composite material into a chip-shaped sample or a sheet-shaped sample; putting the sample into a beaker which is weighed in advance, adding a copper dissolving agent solution, and stirring under a water bath heating condition until the coating is completely dissolved; a new copper dissolving agent, deionized water and absolute ethyl alcohol are used for sequentially cleaning the steel base body and drying the steel base body; calculating the mass ratio of the coating metal according to the mass difference before and after the sample is dissolved; according to the method, a direct dissolving-weighing method is adopted, complex step-by-step detection is simplified into a single process, and the method has the advantages of being easy to operate, safe, environmentally friendly, accurate and reliable and is suitable for detection of various copper-based coating materials including pure copper, brass, bronze, cupronickel and the like, and a practical detection scheme is provided for quality control of copper-steel composite materials.

This utility model relates to a molding die for the lower piece of an automotive front axle assembly. At each processing station of the lower die, a positioning groove is formed by the cooperation of a first positioning block and a second positioning block. The first positioning block includes an integrally formed fixed seat and a conical positioning post. A shaped positioning protrusion extends radially outward from the side wall of the fixed seat. The conical positioning post is located above the shaped positioning post, and its central axis is parallel to the central axis of the fixed seat. The upper die has a conical positioning groove for the conical positioning post to enter. The second positioning block has an L-shaped structure, and its other side wall has a positioning plane. This utility model uses first and second positioning blocks of different shapes for dual positioning, achieving high-precision positioning in multiple directions. By utilizing the conical positioning post in cooperation with the conical positioning groove of the upper die, relative positioning between the upper and lower dies is achieved, thus maintaining the balance of the punches within the upper die during multi-angle punching.