32results about How to "Reduce displacement deviation" patented technology

The invention provides a memory and a forming method thereof, and a semiconductor device. A mask support and a sacrificial layer are formed in self-alignment with a first mask layer corresponding to aword line pattern, a cavity is formed in self-alignment with a second mask layer, so as to define a region in which the memory node contact and the bit line contact are formed, so that the memory node contact and the bit line contact can be sequentially formed in the cavity under the action of an isolation barrier of the mask support and the sacrificial layer. That is, in the process of forming the storage node contact and the bit line contact, By using only one photolithography process, the execution times of the photolithography process are reduced, the problem of large displacement deviation due to multiple photolithography processes is avoided, and the contact resistance between the memory node contact and the memory node contact region, and between the bit line contact and the bit line contact region can be reduced.

The invention relates to the technical field of grating ruling and particularly discloses a grating ruling tool initiative adjusting device having an abbe error correcting function. The grating ruling tool initiative adjusting device comprises a tool rest lifting mechanism, a tool rest supporting frame, a micro positioning worktable, a worktable installation seat, flexible hinges, piezoelectric ceramics, tension springs, a small tool rest and a diamond ruling tool. The piezoelectric ceramics and the micro positioning worktable are in contact through friction, and the four symmetrical flexible hinges enable the micro positioning worktable to have large rigidity in direction except the Z-axis direction. The micro positioning worktable conducts micro positioning movement in the Z-axis direction under the stretching movement of the piezoelectric ceramics, and thus the displacement deviation between the actual position and the ideal position of the diamond ruling tool can be minimized. According to the grating ruling tool initiative adjusting device, a double-axis interferometer is used for measuring the position of the diamond ruling tool in real time, the influence of abbe measurement errors caused by using a one-axis interferometer on the positioning precision of the diamond ruling tool is avoided, the positioning error of the diamond ruling tool can be easily reduced, the grating ruling quality can be improved, and the performance index can be increased.

The invention discloses a three-dimensional full-automatic distribution machine. The three-dimensional full-automatic distribution machine comprises an outer frame, wherein a lifting frame is connected to the outer frame in a sliding mode, four hydraulic cylinder assemblies are connected to the lifting frame, and the lifting frame is pushed to slide up and down on the outer frame by the four hydraulic cylinder assemblies; a traverse moving frame is connected to the lifting frame in the sliding mode, the traverse moving frame can slide from left to right on the lifting frame, a longitudinal moving frame is connected to the traverse moving frame in the sliding mode, and the longitudinal moving frame can slide from front to back on the traverse moving frame; and a hopper assembly is arrangedon the longitudinal moving frame, the hopper assembly comprises a hopper main body, a fixed frame is arranged on the upper part of the hopper main body, a plurality of weighing sensors are arranged onthe lower end of the fixed frame, and the lower ends of the weighing sensors are connected with the longitudinal moving frame. According to the three-dimensional full-automatic distribution machine,a three-dimensional movement driving mode is adopted, the distribution machine can be reliably operated in the directions of an X axis, a Y axis and a Z axis, products are identified, and proper procedures are selected to distribute by a controller, so that automatic distribution is realized, and the distribution requirements of users on different member products are met.

The invention relates to a fiber material friction type drainage anchor rod, and belongs to the technical field of anchor rod support. The fiber material friction type drainage anchor rod comprises ananchoring end, a water filtering film, water inlet holes, a fiber material anchor rod body, a burst cone, an elastic rubber dense ring, a circular serrated joint, a steel tube expansion anchor rod, ahollow drainage hole and a rigid protective sleeve; the anchoring end and the fiber material anchor rod body form an integrated structure; the anchoring end is of a solid structure; the water inlet holes are uniformly formed in the fiber material anchor rod body and the water filtering film; the water filtering film surrounds the outer side of the hollow drainage hole; the periphery of the burstcone is surrounded with the elastic rubber dense ring; the circular serrated joint is arranged at the tail of the burst cone; the outer sides of the elastic rubber dense ring and the circular serratedjoint are sleeved with the rigid protective sleeve; the anchor rod proposed by the invention has a prominent drainage function, has a preventive effect on gushing water in a tunnel, has a good filtering effect, can also grout an anchor body, fills in positions of water flowing in surrounding rock, and timely controls the deformation of the surrounding rock.

The invention discloses a device for locating a female die of a fan blade, wherein the device comprises two fixing blocks respectively pre-embedded in a flange edge of an upper die and in a flange edge of a lower die, internal and external studs respectively in threaded connection into the two fixing blocks, a concave block installed on one of the two fixing blocks, and a convex block installed on the other of the two fixing blocks, and when the upper die and the lower die are assembled, the convex block is inserted into the concave block. According to an exemplary embodiment of the invention, as the concave block and the convex block respectively pass through small eccentric thread holes and are connected with the fixing blocks through fasteners, and the small thread holes are designed in an eccentric manner, the relative horizontal position between the concave block and the fixing block, and between the convex block and the fixing block can be freely regulated within a scope, as a result, the displacement of the upper die and the lower die can be within a controllable scope during die assembly.

The invention discloses an anti-floating anti-pulling-damage polyethylene winding structure wall tube and a construction method thereof. The anti-floating anti-pulling-damage polyethylene winding structure wall tube comprises a tube body which comprises a tube wall and a threaded tube, and the threaded tube is evenly wound around the outer side face of the tube wall; and clamping devices are further included, every two adjacent clamping device arranged left and right are fixedly connected through a connecting rod, each clamping device comprises an upper clamping positioning block and a lower clamping positioning block which are matched, and lantern rings are evenly arranged on the tube wall in a sleeving manner and are connected to the side faces of the upper clamping positioning blocks and the lower clamping positioning blocks through chains. The construction method of the anti-floating anti-pulling-damage polyethylene winding structure wall tube comprises the steps of surveying and setting out, tube ditch excavation, wall tube installation and positioning, wall tube connection, closed water testing and tube ditch backfilling. The construction method is simple in step, the wall tube installation efficiency is improved, the stability and reliability of the wall tube in the paving and connecting process are effectively improved, the level height difference is reduced, and the connecting sealing performance of wall tubes is improved.

The invention discloses a strengthening construction process for a comprehensive pipe rack pre-embedded steel edge water-stop belt and a water-stop steel plate, and belongs to the field of architectural engineering. The strengthening construction process is characterized in that a plurality of positioning ribs are horizontally arranged on the bottom of the water-stop steel plate, a plurality of pairs of strengthening steel bars are mounted at the left side and the right side of the water-stop steel plate, and the water-stop steel plate is squeezed, so that the water-stop steel plate is prevented from longitudinally shifting and transversely shifting, and therefore, displacement deviation of the water-stop steel plate is greatly reduced, an accuracy rate and a qualification rate of the water-stop steel plate pre-embedding material are remarkably increased, construction efficiency is improved, construction quality is guaranteed, and specifications are met. According to the strengtheningconstruction process disclosed by the invention, a double-layer positioning box is adopted to integrally oppositely pull and strengthen the steel edge water-stop belt, so that a strengthening area between the positioning box and the water-stop belt is increased, a condition that the steel edge water-stop belt deviates when the concrete is vibrated as a result of strengthening the steel edge water-stop belt in the prior art is avoided, the accuracy rate and the qualification rate of the steel edge water-stop belt pre-embedding material are remarkably increased, construction efficiency is improved, construction quality is guaranteed, and the specifications are met.

The present application provides a method, device and electronic equipment for identity recognition based on electrocardiographic data. The method includes: determining at least one set of target ECG data from the electrocardiogram signal, wherein each set of target ECG data is data between two adjacent R peaks; based on a set of reference ECG data corresponding to the reference heart rate , adjusting each set of target ECG data to obtain at least one set of adjusted target ECG data; based on the adjusted at least one set of target ECG data and a set of reference ECG data of a preset target identity, identify the Identity of the ECG signal. Through this solution, the accuracy of identification based on electrocardiographic data can be improved.

The invention discloses a greenhouse vegetable seedling transplanting machine which comprises a framework, a transverse rod, a support, a U-shaped frame, a transplanting barrel, a connecting structureand a seedling fork. The transverse rod is fixed onto the framework by the aid of the support, the U-shaped frame is positioned below the transverse rod, the transplanting barrel is positioned belowthe U-shaped frame, the connecting structure is positioned on the lower side of the transplanting barrel, the seedling fork is positioned on the lower side of the connecting structure, and the connecting structure is used for connecting the transplanting barrel with the seedling fork. The greenhouse vegetable seedling transplanting machine has the advantages that the greenhouse vegetable seedlingtransplanting machine additionally comprises the connecting structure, and accordingly the seedling fork of the greenhouse vegetable seedling transplanting machine is convenient to replace and use andcan be tightly connected with the transplanting barrel.

The invention provides a vapor deposition thin coating curing tool, which includes a seat plate, a side plate and a loading block; the side plate is fixed on both sides of the seat plate; the center of the seat plate is provided with a The supporting rib has several grooves evenly distributed on the supporting rib; the loading block is in the shape of a stepped shaft, which is symmetrical in pairs relative to the supporting rib and uniformly distributed along the extending direction of the supporting rib; the small loading block The end is located in the groove of the support rib and is limited by the groove, and the large end of the loading block is located on any upper surface of the seat plate on both sides of the support rib and is contacted and positioned by the upper surface; There are also some screw holes matching the fastening screws evenly distributed on the side plates, and the ends of the fastening screws penetrate between the side plates from the screw holes and connect with the central hole of the outer surface of the large end of the loading block. contact, the fastening screw can apply an axial load to the loading block through the central hole. The invention can reliably control the axial pretightening force, and has accurate positioning and high efficiency.

The invention provides a memory, a forming method thereof, and a semiconductor device. The mask support body and the sacrificial layer are formed by self-alignment using the first mask layer corresponding to the word line pattern, and a cavity is formed by self-alignment in combination with the second mask layer to define the storage node contact and the bit line contact. A region is formed, and under the action of the isolation barrier of the mask support body and the sacrificial layer, a storage node contact and a bit line contact can be sequentially formed in the cavity. That is, in the process of forming the storage node contact and the bit line contact, only one photolithography process is used, which reduces the number of execution times of the photolithography process, and avoids the problem of large displacement deviation due to multiple photolithography processes, and then Contact resistance between the storage node contact and the storage node contact region, and between the bit line contact and the bit line contact region can be reduced.

The invention discloses a blocking mechanism for trolley type switch cabinet contact movable baffles, and aims at solving the problem of jamming in an action process of the contact movable baffles inthe prior art. The device comprises an upper movable baffle and a lower movable baffle arranged on a separation board, an electromagnetic lock arranged on a side wall, a controller arranged on the side wall, a trolley position sensor, a first motor, a second motor, a third motor, a fourth motor, a first travel sensor and a second travel sensor which are respectively connected with the controller,and a grounding shrapnel arranged on a baseboard and fitted to the trolley position sensor, wherein the electromagnetic lock is connected with the controller. According to the scheme above, the mechanism has the advantages of being simple in structure, flexible in action, safe and reliable; and the mechanism is of great practical value and promotional value in the technical field of safety protection.

The invention relates to the technical field of welding, in particular to a welding pressing tool which comprises a machining table. A placing plate is arranged in the center of the upper end face of the machining table, three movable plates are annularly arranged on the outer side of the placing plate at equal intervals, and three pressing mechanisms are arranged on the inner side faces of the three movable plates at equal intervals. Each pressing mechanism comprises first-stage hinge seats, sleeves, spring grooves, first-stage springs, movable rods, second-stage hinge seats, a supporting block, a third-stage hinge seat, a rubber pad, a clamping plate and second-stage springs. Rectangular grooves are symmetrically formed in the left side and the right side of the center position of the inner side face of each movable plate, and sliding blocks are arranged in the rectangular grooves correspondingly. The second-stage hinge seats are fixedly connected to the left sides and the right sides of the front side faces of the supporting blocks correspondingly, and the front ends of the movable rods are hinged to the second-stage hinge seats correspondingly. According to the welding pressing tool, the pressing mechanisms are pulled by a pressing driving mechanism to contract inwards, so that a welding workpiece is pressed, manual operation is avoided, time and manpower are saved, and the working efficiency is improved.

The invention discloses a switch cabinet touch movable retaining plate locking device and mainly solves the problem of jamming when existing touch movable retaining plates act in the prior art. The device comprises an upper movable retaining plate, a lower movable retaining plate, an electromagnetic lock arranged on a side wall, a controller arranged on the side wall, a handcart position sensor, afirst motor, a second motor, a third motor, a fourth motor, a first stroke sensor, a second stroke sensor and a grounded elastic piece arranged on the baseplate and fitted to the handcart position sensor, the upper movable retaining plate and the lower movable retaining plate are arranged on a partition, the handcart position sensor, the first motor, the second motor, the third motor, the fourthmotor, the first stroke sensor and the second stroke sensor are connected with the controller, and the electromagnetic lock is connected with the controller. Through the technical scheme, the switch cabinet touch movable retaining plate locking device has the advantages of simple structure, convenience in operation, flexibility in action, safety and reliability and quite high practical value and popularization value in the technical field of safety protection.

The invention discloses a high-speed braiding machine spindle installation track structure, which includes a turntable and a pair of buffer assemblies. The outer ring of the turntable is fixed with several elongated mounting seats at equal intervals, and a pair of buffer assemblies are respectively installed on the On the two side walls of the mounting seat, the buffer assembly includes a bottom plate, a pair of buffer bodies, a top plate and a striking plate, the bottom plate is fixed on the side wall of the mounting seat, and a pair of buffer bodies are slidably arranged on the The front end of the bottom plate, the top plate is slidingly arranged at the front end of a pair of buffer bodies, and the strike plate is connected to the front end of the top plate. Due to the reasonable structure of the present invention, the impact force of the slider can be effectively reduced, making the present invention stable It is better, safer to use, and has a longer service life.

The invention provides a traction wheel with the displacement deviation capable of being reduced. The traction wheel comprises a wheel body, a wiring device and a laser pen. The wiring device is tangent to wheel body. The laser pen is simultaneously tangent to the wiring device and the wheel body and is fixedly provided with a mini level. The wiring device comprises a housing, a chassis, a lockingblock, a winding drum and a toothed disc. The chassis and the locking block are fixedly arranged on the traction wheel. The winding drum is used for winding a lead wire. The toothed disc sleeves thewinding drum. The toothed disc and the drum are coaxial and rotate synchronously. The locking block comprises a knob and a limiting part. The knob is provided with a positioning rod and a locking partpenetrating through the positioning rod. The locking part is provided with a toothed part which meshes with the toothed disc. When the knob is rotated to enable the toothed disc to mesh with the locking part, the locking part is stopped by the limiting part, a guide wheel is precisely positioned, the displacement deviation of the traction wheel is reduced, positions can be simply determined, operation is facilitated, and less equipment is used.

The invention discloses a device for locating a female die of a fan blade, wherein the device comprises two fixing blocks respectively pre-embedded in a flange edge of an upper die and in a flange edge of a lower die, internal and external studs respectively in threaded connection into the two fixing blocks, a concave block installed on one of the two fixing blocks, and a convex block installed on the other of the two fixing blocks, and when the upper die and the lower die are assembled, the convex block is inserted into the concave block. According to an exemplary embodiment of the invention, as the concave block and the convex block respectively pass through small eccentric thread holes and are connected with the fixing blocks through fasteners, and the small thread holes are designed in an eccentric manner, the relative horizontal position between the concave block and the fixing block, and between the convex block and the fixing block can be freely regulated within a scope, as a result, the displacement of the upper die and the lower die can be within a controllable scope during die assembly.

The invention discloses a hoisting device for constructing a long-span wooden lounge bridge and a method. The hoisting device comprises a hoisting mechanism, a supporting mechanism, a horizontal moving device and a second winding mechanism. Two columns are parallelly arranged on the river bank at the same side. The columns are fixedly connected to the river bank via bases. The supporting mechanismis fixedly connected between the columns on the river banks at both sides. The supporting mechanism is movably connected with the horizontal moving device. Two sides of the horizontal moving device are respectively connected to the second winding mechanism by cables over first guiding wheels. The hoisting mechanism is connected to a lower side of the horizontal moving device by a hoisting rope. The method comprises: river bank foundation construction, supporting mechanism installation, horizontal moving device installation, hoisting mechanism installation, second winding mechanism installation and hoisting device trial operation. The installation method has simple steps and strong practicability, and construction of wooden lounge bridges of different lengths can be satisfied, thereby greatly improving the construction efficiency, shortening the construction period and reducing the labor intensity of manual operation.

The invention discloses a construction technology for pre-embedded steel edge waterstops and waterstop steel plates in a comprehensive pipe gallery, belonging to the field of construction engineering. In the present invention, several positioning ribs are arranged horizontally at the bottom of the water-stop steel plate; several pairs of reinforcement bars are also installed on the left and right sides of the water-stop steel plate to squeeze the water-stop steel plate, preventing the vertical and lateral deviation of the water-stop steel plate, thus greatly The displacement deviation of the water-stop steel plate is greatly reduced, the accuracy and pass rate of the pre-embedded material of the water-stop steel plate are significantly improved, the construction efficiency is improved and the construction quality is guaranteed to meet the specification requirements. The present invention adopts the double-layer positioning box to reinforce the steel edge waterstop as a whole, which increases the reinforcement area of ​​the positioning box and the waterstop, and avoids the reinforcement of the steel edge waterstop in the prior art, which will cause the steel edge waterstop to be in the concrete. The deviation occurs during vibration, which significantly improves the accuracy and qualification rate of the pre-embedded materials of the steel edge waterstop, improves the construction efficiency, and ensures the construction quality to meet the specification requirements.

The invention discloses a sorting device and method for a material piece. The material piece is provided with a rod part and an expanding part, wherein the cross section of the expanding part is larger than the cross section of the rod part. A limiting part is formed between the rod part and the expanding part. The sorting device comprises a guiding mechanism, a pushing mechanism and a material falling mechanism. The guiding mechanism comprises a guiding groove. The material falling mechanism comprises a material falling groove. The material falling groove is used for receiving the material piece when the limiting part of the material piece is located between the guiding groove and the material falling groove. The guiding groove abuts against the limiting part when the limiting part of thematerial piece is located on the side, away from the material falling groove, of the material piece. The sorting mechanism comprises an auxiliary material removal mechanism. Stress can be applied tothe material piece by the auxiliary material removal mechanism, so that gaps exists between the guiding mechanism and the material piece when the limiting part of the material piece is located betweenthe guiding groove and the material falling groove. The sorting device and method for the material piece at least have the following advantages that the front and back of the material piece can be recognized accurately and sorted.

The invention provides an electro-hydraulic control system, method and device. The electro-hydraulic control system can comprise a hydraulic cylinder, an electro-hydraulic proportional valve and the control device, wherein the hydraulic cylinder controls moving of the load, the electro-hydraulic proportional valve controls the direction and the flow quantity of hydraulic oil inside an oil box flowing into the hydraulic cylinder according to control signals used for controlling a valve core of the electro-hydraulic proportional valve to move, and the control device calculates a deviation valuebetween a displacement target value and an actual displacement value of the hydraulic cylinder, corrects the deviation value according to the pressure relationship between a first pressure value of arodless cavity of the hydraulic cylinder and a second pressure value of an oil inlet of the electro-hydraulic proportional valve and generates the control signals based on the corrected deviation value. According to the electro-hydraulic control system, method and device, by means of real-time correction on deviation signals, the correction accuracy is improved, displacement deviation caused by load disturbance force is reduced, and the system stiffness is increased.

The invention discloses a clamping mechanism of a glue binding machine. The clamping mechanism comprises a book clamping frame (1), a motor (2), and a clamping and pressing device (3). The clamping and pressing device (3) comprises a fixed plate (31) and a movable plate (32), which are parallel to each other. The fixed plate (31) is fixedly arranged on the book clamping frame (1). The movable plate (32) is connected to the motor (2) through a screw rod (32). A clamping and pressing plate (34) is connected to the movable plate (32) through a pressure spring (35). Through the abovementioned structure, the fixed plate (31) is fixed and is capable of reducing the displacement deviation caused by wear of machine, thus the neatness and appearance of books are both improved after glue binding, the pressure spring is arranged between the clamping and pressing plate (34) and the movable plate (32) so as to reduce the vibration effectively, and the paper is easy to place therefore.

The invention relates to an opening-closing control method for a barrel valve. The opening-closing control method comprises the following steps: S1 in a barrel valve opening process, firstly performing delay flat pressing operation on the barrel valve and then adopting a proportional solenoid valve to perform synchronously regulate in a process of lifting the barrel valve to a full opening state, and finally keeping the barrel valve at the full opening position; S2 in a barrel valve closing process, firstly performing delay flat pressing operation on the barrel valve, then adopting the proportional solenoid valve to perform synchronously regulate in a process of dropping the barrel valve to a full closing state, and finally keeping the barrel valve at the full closing position. In the barrel valve opening and closing processes, the operation is stable, displacement deviation (the maximal deviation within 3mm) of each servomotor is relatively small, the regulating times for the proportional solenoid valve are reduced, the regulating effect is relatively good, and the lower cavity pressure of the servomotor is kept balanced.

The invention relates to the technical field of plate processing, in particular to a stone crystal wallboard production device with a carving groove, which comprises a platform main body and longitudinal displacement mechanisms fixedly connected to two sides of the platform main body, vertical plates are movably connected to the longitudinal displacement mechanisms on the two sides, and a transverse displacement mechanism is fixedly connected between the vertical plates on the two sides. A bearing assembly and an auxiliary assembly are slidably connected to the middle of the upper end face of the platform body, the bearing assembly is matched with the auxiliary assembly to clamp and fix a stone crystal wallboard placed between the bearing assembly and the auxiliary assembly, and displacement deviation in the carving machining process is reduced. Supporting bases are fixedly connected to the two sides of the lower end face of the platform body, driving mechanisms are fixedly connected to the positions, corresponding to the auxiliary assemblies and the bearing assemblies, between the two supporting bases, and the driving mechanisms drive the bearing assemblies to move on the platform body so that the stone crystal wallboard can be stably placed on the platform body.

The invention provides an open-loop control type manipulator aiming to solve the technical problem in the prior art that the conventional open-loop control type manipulator produces large displacement error when resetting. The open-loop control type manipulator comprises a rack and a manipulator body moveably mounted on the rack, wherein a first coil is arranged on the manipulator body; a second coil is arranged on the rack; the first coil and the second coil are connected in parallel to a power supply circuit; the position of the first coil mutually corresponds to that of the second coil; the cross section of the first coil is superposed with or parallel to the cross section of the second coil; during use, when the automatic resetting of the manipulator is completed, in the interval between which the manipulator stops resetting and the next loop begins, the first coil and the second coil are simultaneously fed with currents in opposite directions, and the first coil and the second coil are mutually attracted.

The invention provides a magneto-rheological elastomer and piezoelectric hybrid control type shield hobbing cutter. An annular groove is formed in the circumferential surface of a cutter body, a piezoelectric device is arranged in the annular groove, a cutter ring is arranged on the annular groove and is in contact with the piezoelectric device, and a plurality of pressure sensors are arranged inthe cutter ring; end covers are arranged on the two sides of the cutter body in a sealing mode, a cutter shaft extends out from center holes of the end covers on the two sides, a cutter shaft seat sleeves the two ends of the cutter shaft, and the cutter shaft seat is filled with the magneto-rheological elastomer wound an electromagnetic coil; an electricity storage device is correspondingly connected with the piezoelectric device, the electromagnetic coil and a controller, and the pressure sensors are connected with the controller; and the piezoelectric device generates high-frequency currentsafter being pressed, electric energy is stored in an energy storage device, the pressure sensors detect pressure of the cutter ring and transfer the pressure to the controller, when the pressure reaches a threshold value, the energy storage device is controlled to supply electricity to the electromagnetic coil, a variable magnetic field is applied to the magneto-rheological elastomer, then the mechanical property of the magneto-rheological elastomer is adjusted, the rigidity of the position of the cutter shaft is changed, and greater power is provided for cutting tools.

The invention provides a traction wheel with the displacement deviation capable of being reduced. The traction wheel comprises a wheel body, a wiring device and a laser pen. The wiring device is tangent to wheel body. The laser pen is simultaneously tangent to the wiring device and the wheel body and is fixedly provided with a mini level. The wiring device comprises a housing, a chassis, a lockingblock, a winding drum and a toothed disc. The chassis and the locking block are fixedly arranged on the traction wheel. The winding drum is used for winding a lead wire. The toothed disc sleeves thewinding drum. The toothed disc and the drum are coaxial and rotate synchronously. The locking block comprises a knob and a limiting part. The knob is provided with a positioning rod and a locking partpenetrating through the positioning rod. The locking part is provided with a toothed part which meshes with the toothed disc. When the knob is rotated to enable the toothed disc to mesh with the locking part, the locking part is stopped by the limiting part, a guide wheel is precisely positioned, the displacement deviation of the traction wheel is reduced, positions can be simply determined, operation is facilitated, and less equipment is used.