473 results about "Traction system" patented technology

The invention provides a railway flexible traction system based on multi-source fusion. The system is composed of a central control unit, a V / v traction transformer unit and a multi-port flexible interconnection unit. The V / v traction transformer unit comprises a first power supply arm, a second power supply arm and a third power supply arm, the input ends of the V / v traction transformer unit are connected with a public power grid, the first and second power supply arms are connected to the multi-port flexible interconnection unit, and the third power supply arm provides passive support for a traction network. The multi-port flexible interconnection unit comprises a two-phase rectification module, a photovoltaic power generation module, an energy storage module and a single-phase inversion module which are commonly connected to a DC bus. The central control unit adjusts the output power of the multi-port flexible interconnection system and the control strategy of the single-phase inversion module in real time so as to realize flexible consumption of new energy and improvement of power supply stability. The system has the advantages of compatibility, cost effectiveness, new energy access and consumption, power supply reliability improvement, electric energy quality optimization, high adaptability and the like, and is suitable for upgrading and reconstruction of newly-built railway lines and existing railway lines.

The invention provides a traction power supply system control method based on multi-objective optimization, and the method comprises the following steps: S1, determining an initial control variable of a traction system, the initial control variable comprising converter power of an alpha power supply side and a beta power supply side of the traction power supply system and train braking resistor dissipation power of the alpha power supply side, the initial control variable is used as input to construct a regenerative braking energy MPC prediction model; s2, predicting a state variable of a next moment based on a regenerative braking energy MPC prediction model, wherein the state variable comprises output power of a traction substation, total dissipation power of a brake resistor, output power of an energy storage system and a charge state of the energy storage system; and S3, constructing a multi-objective optimization function based on the state variable at the next moment, converting the multi-objective optimization function into a quadratic programming form for solving to obtain a control variable sequence, and taking a first item of the control variable sequence as control input to control the traction power supply system to work.

The invention relates to the technical field of robots, in particular to a redundancy-driven variable-stiffness ankle joint structure which comprises an ankle assembly connected to a shank main body through a central hinge shaft; the dual-drive unit comprises a first drive unit and a second drive unit which are independently controlled, and the first drive unit and the second drive unit are fixedly mounted in the shank main body; the traction system comprises a first eccentric wheel and a second eccentric wheel which are coaxially connected with the output ends of the first driving unit and the second driving unit respectively; by means of a redundant drive framework and a variable rigidity adjusting mechanism, elastic buffering and dynamic rigidity adjusting can be achieved, the impact adaptability is improved, the dual-drive unit can be prevented from being directly impacted, and the service life of the dual-drive unit is prolonged. Damage to a motor gear is reduced, the rigidity can be quickly reduced for buffering in an impact scene, and the rigidity is improved for maintaining the posture during stable supporting.

The utility model relates to an automatic traction system for strip steel rolling in a hot rolling production line. The automatic traction system comprises a sliding rail arranged on a plate link chain of the hot rolling production line in the strip steel conveying direction; a sliding device; a lifting device; a control unit; a trailer wagon device; the trailer wagon device comprises a suspension platform, a front guide mechanism, a rear guide mechanism and a roller mechanism, and the roller mechanism is installed on the suspension platform and used for driving strip steel to move forwards and backwards; the front guide mechanism and the rear guide mechanism are installed on the front portion and the rear portion of the suspension platform respectively and open a channel for strip steel to penetrate through. The front end opening of the front guide mechanism is over against the finishing roller inlet; the rear end of the rear guide mechanism extends to the snake vibration area and is in butt joint with the snake vibration outlet. The front guide mechanism, the rear guide mechanism and the roller mechanism can be integrally and synchronously opened or retracted in the direction perpendicular to the conveying direction of the plate chain. According to the utility model, continuous and stable strip steel conveying can be realized without waiting or pause, and the operation efficiency is high.

This invention provides a reciprocating traction system, comprising two sets of longitudinal double-line reciprocating traction systems and one set of horizontal double-line reciprocating traction systems mounted on one side of an anchorage; the two longitudinal double-line reciprocating traction systems are respectively mounted on the upstream and downstream sides, and the horizontal double-line reciprocating traction system is connected to one end of the two longitudinal double-line reciprocating traction systems; the horizontal double-line reciprocating traction system includes a first towing track, a second towing track, a first horizontal traction mechanism, a second horizontal traction mechanism, and a horizontal traction machine; the first and second towing tracks are staggered; this invention can achieve the turning of the main cable strands without the need for a tower crane, reducing the construction period and labor costs associated with tower cranes, and the invention has low tonnage requirements for the horizontal traction machine of the main cable strands, which can reduce equipment investment costs; the method of this invention can achieve simultaneous turning and traction of two main cable strands, improving traction efficiency.

The invention provides a tension determination method and device, electronic equipment and a medium. The method comprises the steps that the current friction torque and the current actual torque of a traction roller driving motor of a target tension section are obtained; acquiring the current average torque of the traction system; according to the current friction torque and the current actual torque of a traction roller driving motor of the target tension section and the current average torque of the traction system, the traction tension torque of the target tension section is obtained; and the current material tension of the target tension section is obtained according to the preset unwinding tension and the traction tension torque of the target tension section.

The invention discloses an intelligent cable traction system and a cable traction laying control method. A cable traction machine can electrically pull a traction rope and detect traction force in real time. And when the traction force exceeds a preset traction high threshold value, the cable winding and unwinding mechanism can be controlled to reduce the winding speed, so that the traction rope wound on the traction wheel is properly loosened, and the traction force is gradually recovered to be stable. And meanwhile, the cable winding and unwinding mechanism automatically adjusts the winding speed according to extrusion force data fed back by the pressure detection assembly, and it is ensured that the extrusion force is maintained within the preset parameter range. According to the embodiment of the invention, the extrusion force and the traction force are creatively combined, the winding speed of the cable winding and unwinding mechanism is comprehensively regulated and controlled, and the intelligent cable traction system is always in a reasonable working interval during traction and winding of the traction rope through an intelligent control mode, so that automatic traction and winding of the traction rope such as a steel wire rope are realized; therefore, the automatic traction operation of the cable connected with the traction rope is completed, and the intelligence and safety of cable laying construction are improved.

The invention discloses a main cable rapid traction method and system, and the method comprises the steps: arranging a traction winch and a main cable traction cable on a platform of a tunnel anchor portal of a starting bank, arranging in-tunnel traction systems in tunnel anchors on two banks, and completing the erection of the traction systems: arranging a cable disc beside a catwalk surface of the tunnel anchor portal of the starting bank, and rotating a cable strand into the catwalk surface through a steering wheel, pulling the cable strand by using an intelligent pulling device until a terminal bank tunnel anchor is reached; a main traction system is used for carrying out secondary dragging traction on a main cable passing section in the hole, then a traction system in a terminal bank hole is used for carrying out relay traction in the hole, and a cable strand anchor head is pulled to the front anchor face of a terminal bank anchor plug body and temporarily anchored; a tower crane, a crawler crane and a truck crane are matched to unfold a cable disc, and a cable head of a main cable strand on the cable disc is moved out; a traction system in the initial bank hole is used for pulling a cable strand head to the front anchor face of the anchor plug body, temporary anchoring is conducted, and traction is completed; by optimizing the traction system assembly and layout, the structure of the traction system is simplified, and the traction efficiency of the main cable strand is improved.

The invention relates to the technical field of roller coating hyperbolic aluminum plate machining control, in particular to an edge auxiliary traction system and method for longitudinal large-curvature forming of a roller coating hyperbolic aluminum plate. The edge auxiliary traction system comprises a clamping pre-deformation unit, when a main stretcher is started, a traction clamping jaw pulls down at a basic speed, and a dynamic proportional relation between the edge stretching speed and the central stretching speed is established; during stretching, when the displacement increment reaches a threshold value, the traction force is proportionally distributed according to the distance from the center line, the pull-down force is updated in real time, when the strain deviation exceeds the limit, a deviation area is positioned through a multi-modal array, the traction speed and the pull-down force of the area are increased, and the local curvature radius reaches a critical range, a reinforced traction mode is started; speed and plastic flow phase locking and grain orientation regulation and control are achieved, traction force is maintained till stress is released in the pressure maintaining stage, the longitudinal large-curvature forming precision of the roller-coated hyperbolic aluminum plate is improved, wrinkles and cracks are reduced, and the method is suitable for machining of the high-precision hyperbolic aluminum plate.

The utility model discloses a traction winding and unfolding type greenhouse heat preservation structure which comprises a supporting system, a traction system, a winding system, a power system and a control system. The supporting system is used for supporting, guiding and sealing in the moving process of the sliding heat preservation quilt, the sliding heat preservation quilt comprises a driving edge located at the length end of the sliding heat preservation quilt, and pulleys matched with guide rails of the supporting system are arranged at the two ends of the driving edge respectively. The traction system is used for providing direct traction force in the unfolding process of the sliding heat preservation quilt and providing tension force in the rolling process of the sliding heat preservation quilt. The winding system directly participates in winding in the winding process of the sliding heat preservation quilt and provides tension in the unfolding process of the sliding heat preservation quilt to avoid stall and over-unwinding of the heat preservation quilt. The power system provides a power source and a tension source in the unfolding and rolling process of the sliding heat preservation quilt. The control system controls the sliding heat preservation quilt to be unfolded and wound by controlling electric control components such as a motor, a traction brake and a winding brake.

The utility model provides a facial paralysis rehabilitation training robot which comprises a head-mounted robot body, a power system and a traction system, and the power system and the traction system are both installed on the head-mounted robot body. The head-mounted robot body is provided with a guide panel, the traction system passes through the guide panel from the head-mounted robot body and extends to a face area, and / or the traction system does not pass through the guide panel from the head-mounted robot body and extends to the face area; and the power system drives the traction system to pull or relax target facial muscles of the patient. The traction system is driven by the power system to move, appropriate force and resistance are applied to facial muscles of a patient to promote movement and activity of the muscles, the activity range of the facial muscles can be increased, neuromuscular connection can be improved, recovery of facial expressions can be promoted, and appropriate force and resistance can be provided; therefore, the patient is helped to gradually recover the functions of facial muscles.

The invention relates to a cable hanging construction method for a sling tower of a steel truss arch bridge, which comprises the following steps: mounting a tower top hanging bracket at the top end of the sling tower, and mounting a tower top cable traction system on the tower top hanging bracket; a bridge floor cable traction system is installed on an upper-layer bridge floor of the side-span steel beams, an arching frame beam crane is installed on the steel truss arch rib, and a front-end cable traction system is attached to the arching frame beam crane. A tower top cable traction system and a bridge floor cable traction system are used for respectively pulling the two ends of the side span sling, the tower top cable traction system and a front end cable traction system are used for respectively pulling the two ends of the midspan sling, and the midspan sling is temporarily hung on the steel truss arch rib and the sling tower; and finally, side span slings are anchored on the side span steel beams and the sling towers, and middle span slings are anchored on the steel truss arch ribs and the sling towers. The tower top cable traction system is installed on the tower top hanging bracket, tower end hanging of the side-span sling or the middle-span sling is carried out, and the problem that sling hanging cannot be carried out through a tower crane is effectively solved.

A construction method of steel pipe lining in a linear hydraulic tunnel is provided, including the following steps: S1, symmetrically installing a plurality of pumping pipes and grouting pipes from two ends of a tunnel to a middle of the tunnel respectively; S2, conveying steel pipes into the tunnel from one end of the tunnel through a traction system and a jacking system in turn, and welding all the steel pipes as a steel pipe lining of the tunnel; S3, installing a plurality of supporting structures at a certain distance inside the steel pipe lining, and installing sealing plates between the steel pipes at two ends of the tunnel and the tunnel; S4, pouring fine aggregate concrete from the middle of the tunnel to outside in turn; and S5, sequentially pouring cement slurry from the middle of the tunnel to the outside through the plurality of the grouting pipes.

The invention provides a bumper assembly low-speed collision test system and method, and the system comprises a mobile barrier trolley, a universal rapid installation clamp, a multi-sensor integrated measurement module, and a data collection and processing system, and can adapt to different bumper assemblies to be tested through the universal rapid installation clamp, simulates the real collision process, and improves the test precision. In the process that the traction system drives the movable barrier trolley to move along the track to conduct the collision test, the multi-sensor integrated measurement module can collect collision data and draw a data curve, and the accuracy of the collision test result is improved. And then the data acquisition and processing system scores the maintenance economy, the energy absorption efficiency, the passenger protectiveness and the structural integrity according to the collision data and the data curve, grades the collision test result according to the scoring result, and finally can output a depth test report containing rating and improvement suggestions. The method is used for supporting and improving the design and optimization capability of the bumper assembly.

The invention relates to the technical field of structural test loading, in particular to a loading device suitable for a low-cycle reciprocating pure torsion test. In order to solve the problem that pure torque cannot be applied to a structure in the prior art, the novel loading device suitable for the low-cycle reciprocating pure torque test is provided and comprises an XY sliding rail system, two reaction walls and two traction systems, the XY sliding rail system comprises a first-layer rail set, a second-layer rail set and a third-layer rail set, the XY sliding rail system is located between the two reaction walls, and the two traction systems are located between the first-layer rail set and the second-layer rail set. The second-layer track set is slidably connected to the first-layer track set in the X-axis direction, the third-layer track set is slidably connected to the second-layer track set in the Y-axis direction, one ends of the two traction systems are hinged to the two reaction walls respectively, and the other ends of the two traction systems are hinged to the two ends, in the Y-axis direction, of the third-layer track set respectively. The two traction systems are arranged in parallel, and the included angle between each traction system and the three layers of track sets is an acute angle. According to the invention, the low-cycle reciprocating pure torsion test of the structure can be realized.

The invention relates to the technical field of radio frequency microwave measurement, in particular to a tested piece harmonic test link and an active load traction system and method.The system comprises a control module and a test link. Determining a test signal value of the vector signal source in the test link and a phase adjustable signal value of the first adjustable phase vector signal source according to the target mismatch degree; then, a plurality of impedance points on the Smith chart are simulated by adjusting the amplitude and the phase of the first adjustable phase vector signal source, the vector signal source is controlled to send out a test signal value, and the first adjustable phase vector signal source is controlled to send out a phase adjustable signal value, so that a tested piece is tested; and finally, obtaining a harmonic value corresponding to each impedance point, and obtaining the maximum harmonic of the tested piece under the target mismatch degree according to the harmonic value corresponding to each impedance point. According to the invention, the impedance adjusting range and precision are higher, and the adjusting speed is higher.

Described here are methods, systems, and devices, useful for minimally invasive surgical procedures. The methods may include introducing a grasper through an opening into an abdominal cavity, grasping a portion of a left lobe of a liver with the grasper, rotating the grasper towards a control element located outside the abdominal cavity by applying a magnetic field to the grasper across a body wall, and moving the control element over a set of ribs such that the liver bends into a folded configuration.

The invention provides a traction system with broken wire detection device, and aims to solve the problem of how to realize online detection of broken wire. The traction system comprises a traction wheel, a traction steel belt and a rope head combination, and further comprises a normally open relay and a power supply. Two ends of the coil of the normally open relay are connected to the positive pole of the power supply and the rope head respectively, the negative pole of the power supply is grounded, and the normally open contact of the normally open relay serves as a switch of an alarm circuit. The traction system has the positive effect of realizing online detection of whether the traction system has the phenomenon of broken wire, and eliminating the hidden danger of the traction system.

The invention discloses a pantograph conductive structure without a supporting insulator. The pantograph conductive structure comprises a conductive rod, a sliding rail group, an upper arm plate and two flexible wire groups, the upper end of the conducting rod is hinged with the upper arm plate, and the lower end is connected to the slide rail group; the upper arm plate is connected with the conducting rod through a flexible wire set, the conducting rod is connected with the sliding rail set through another flexible wire set, and movable connection with the pantograph is achieved. The problem that a current fixed connection transmission mode of a traditional pantograph with a supporting insulator cannot meet the movable current transmission requirement of the pantograph without the supporting insulator is solved, the pantograph can be self-adapted to various states of working or falling of the pantograph, effective current transmission of the pantograph without the supporting insulator is achieved, and electric energy is provided for a vehicle traction system.

The invention relates to a folded plate type folding traction system and method for trenchless pipeline repair. The system comprises a traction machine, a feeding mechanism and a folding device used for folding a lining pipe, a pressing roller mechanism and a folding mechanism are arranged on a conveying platform of the folding device, the pressing roller mechanism is located on the feeding side of the conveying platform and provided with a transverse roller pair, and the two sides of an upper roller of the pressing roller mechanism are each provided with an annular protrusion used for pressing an indentation; the folding mechanism is located in front of the pressing roller mechanism and provided with a left folding plate and a right folding plate, the folding plates are rotationally connected with the conveying platform through folding plate rotating shafts, and the folding plate driving device is in driving connection with the corresponding folding plate rotating shafts. According to the method, the traction system is adopted for traction of the lining pipe, and the lining pipe is automatically folded into a folded state when passing through the folding device. Automatic folding of the lining pipe is achieved, the labor intensity can be reduced, and the working efficiency can be improved.

The invention relates to a main cable maintenance platform traction winding device and a winding method. A main cable maintenance platform comprises an outer portal frame and an inner portal frame which are connected in a sleeved mode and can slide relatively. The traction winding device comprises traction connecting assemblies A installed on the left side and the right side of the outer front door frame, traction connecting assemblies B installed on the left side and the right side of the inner front door frame and a traction mechanism connected with the traction connecting assemblies A and the traction connecting assemblies B in a winding mode. Winding steel wire ropes of the winches A and B; a hook pulley and a rolling pulley in the traction winding device are correspondingly mounted on frames on the two sides of the front ends of the inner front door frame and the outer front door frame respectively and are easy to dismount or mount, so that an operator can conveniently inspect the traction device, replace parts and the like in the daily maintenance and repair process; compared with a complex traditional traction system, the traction winding device has the advantages that the maintenance time can be greatly shortened, and the utilization rate of equipment is increased.

The invention discloses an anti-shaking protection device for flexible parts of an elevator. The anti-shaking protection device comprises an auxiliary traction system, a first flexible part limiting device and a second flexible part limiting device. The auxiliary traction system comprises a driving motor, an auxiliary traction wheel, an auxiliary guide wheel and an auxiliary steel wire rope; the auxiliary steel wire rope is hung on an auxiliary traction wheel and an auxiliary guide wheel which are arranged at the upper part of the hoistway in a closed ring shape, and is tensioned through a pair of auxiliary guide wheels which are arranged at the lower part of the hoistway; the auxiliary guide wheel arranged on the upper portion of the hoistway is close to the lift car side guide rail, and the auxiliary guide wheel arranged on the lower portion of the hoistway coincides with the auxiliary guide wheel arranged on the upper portion of the hoistway in the vertical direction, so that the side, close to the lift car side guide rail, of the auxiliary steel wire rope is parallel to the lift car side guide rail. The first flexible part limiting device is arranged on the upper portion of the lift car, fixedly connected with the auxiliary steel wire rope and driven by the auxiliary steel wire rope to move up and down along the lift car side guide rail, and the moving direction is the same as that of the lift car. The first flexible part limiting device is always located at a first fixed proportion position from the car to the top of the shaft in the shaft, and is used for limiting the shaking range of a traction steel wire rope at the upper part of the car; the second flexible part limiting device is arranged on the lower portion of the lift car, fixedly connected with the auxiliary steel wire rope and driven by the auxiliary steel wire rope to move up and down along the lift car side guide rail, and the moving direction is the same as that of the lift car. And the second flexible part limiting device is always located at a second fixed proportion position from the car to the bottom of the shaft in the shaft, and is used for limiting the shaking range of a compensation rope or a traveling cable at the lower part of the car.

The utility model relates to the technical field of airport luggage traction, in particular to a luggage barrow traction system which comprises a tractor, a control center and at least one auxiliary device, the tractor is used for dragging a luggage barrow, and the auxiliary device is used for monitoring the environment conditions of the tractor and the periphery of the luggage barrow. The tractor, the control center and the at least one auxiliary device communicate with one another. The luggage barrow traction system is provided with at least one auxiliary device which is used for monitoring the environment conditions around the tractor and the luggage barrow, the tractor, the control center and the at least one auxiliary device communicate with each other, and the auxiliary device can enable the tractor and the luggage barrow to avoid obstacles. The luggage barrow is prevented from colliding with an obstacle in the traction process of the tractor, the traction and movement efficiency of the tractor on the luggage barrow is higher, in addition, after the auxiliary device is arranged, workers do not need to conduct on-site commanding, on-site accidents are reduced, and manpower is saved.

The invention belongs to the technical field of traction instruments, and particularly relates to orthopedic traction equipment which comprises a matching butt joint mechanism and a flexible lifting traction mechanism. In order to prevent blood vessels from being pressed and blood circulation from being affected during traction, the elastic traction system is arranged, the traction force is adjusted in a worm and gear transmission mode, more labor is saved, additional loads do not need to be prepared during adjustment, and more convenience is achieved; the adjacent vibration air bags can alternately support the legs of a patient, meanwhile, vibration generated by the vibration air bags can massage the patient, blood circulation of the patient is promoted, and discomfort is relieved. The matching docking mechanism can be mounted on different types of sickbeds, and traction treatment can be performed on a patient without moving the patient; the flexible lifting traction mechanism can be adjusted in a lifting mode according to the legs of the patient, the legs of the patient can be better supported, and the discomfort of the patient is relieved.

The invention discloses a comprehensive diagnosis method for clamping, separating and clamping faults of a contactor for a traction converter, is used for solving the technical problem that faults are likely to be misreported in the prior art, and belongs to the technical field of converter fault diagnosis. The detection loop adopts a normally-open auxiliary switch parallel connection mode to feed back the state of the contactor, so that the false alarm rate of the contactor clamping failure can be reduced; the detection loop adopts a normally-open auxiliary switch series connection mode to feed back the contactor state, so that the clamping fault false alarm rate of the contactor can be reduced; the control unit adds a reset condition control strategy to reduce the fault false alarm rate; the control strategy that the control unit detects the state of the auxiliary switch of the contactor and detects whether the voltage and current values in the loop meet the threshold value can reduce the fault false alarm rate. The accuracy of fault diagnosis of the contactor for the traction converter is improved, the fault level is reduced to the maximum extent, meanwhile, the comprehensive diagnosis method is simple in judgment logic, the occupancy rate of computing resources of a control unit is low, and the overall performance of a traction system and the operation efficiency of a locomotive are improved.

The utility model relates to the technical field of wire cutting, and discloses a diamond wire cutting machine traction system which comprises a base, a diamond wire and a placing frame, the top of the base is fixedly connected with a supporting frame, the two sides of the top end of the supporting frame are rotationally connected with a wire inlet wheel and a wire outlet wheel respectively, and an encoder is arranged on one side of the wire outlet wheel. A first tension adjusting assembly and a second tension adjusting assembly are arranged on the two sides of one end of the supporting frame correspondingly, the first tension adjusting assembly and the second tension adjusting assembly each comprise a fixing support, and one side of each fixing support is rotationally connected with a first tension wheel and a fixed wheel. A traditional traction servo motor is omitted, a high-precision encoder is additionally arranged on a wire outlet wheel and serves as a constant-speed wheel to control stable operation of a whole wire net, a traction shaft cannot form a slipping effect in the whole operation process of equipment, and therefore the service life of the traction shaft is greatly prolonged, and the occupied area is reduced.

An autonomous utility vehicle can include a towing component. The vehicle can further include a fastening component attached to the towing component, and configured to fasten to a cable to be pulled by the vehicle. The vehicle can further include processor(s) coupled to a memory having instructions stored therein, which when executed by the processor(s), cause the vehicle to: detect a tension of the cable, determine whether the tension of the cable is detected, in response to determining that the tension of the cable is detected, determine whether the tension of the cable has exceeded a tension threshold, and in response to determining that the tension of the cable has exceeded the tension threshold, adjust at least one of: a speed of the vehicle or a heading of the vehicle.

The invention belongs to the technical field of shockproof devices, and particularly relates to a museum cultural relic shockproof base which comprises tempered glass, a damping mechanism and a main base. Through the dual energy dissipation design of the damping spring and the vibration damper of the traction system, earthquake impact energy is effectively absorbed, the damping spring buffers longitudinal impact through deformation, the vibration damper counteracts transverse vibration through inertia reverse vibration, and the fracture risk of the traction wire is remarkably reduced; the damping pendulum bob, the magnetic pole rod and the damping magnet are combined, horizontal vibration is counteracted through inertia of the pendulum bob, meanwhile, the swing amplitude is actively restrained through magnetic pole repulsive force, and cultural relics are prevented from being damaged by resonance.

The utility model relates to an elevator traction system. The elevator traction system comprises a lift car, a counterweight and a traction machine. The counterweight is arranged on one side of the lift car, and the traction machine is arranged between the lift car and the counterweight. The first car roof wheel and the second car roof wheel are arranged on the top of the car side by side. The first car diversion sheave and the second car diversion sheave are arranged between the first car top sheave and the second car top sheave, and the first car diversion sheave and the second car diversion sheave are staggered up and down. The first counterweight wheel and the second counterweight wheel are arranged on the top of the counterweight, and the counterweight diversion sheave is arranged between the first counterweight wheel and the second counterweight wheel. The traction rope sequentially bypasses the first car top wheel, the first car diversion sheave, the second car diversion sheave, the second car diversion sheave, the traction wheel, the first counterweight wheel, the counterweight diversion sheave and the second counterweight wheel. Due to the fact that the first lift car diversion sheave and the second lift car diversion sheave are staggered up and down, the situation that the first lift car diversion sheave and the second lift car diversion sheave are arranged side by side and cannot be overlapped and arranged can be avoided, and the size requirement of the elevator with the small machine room can be met.

One variation of a method includes, during a first time period: detecting a direction of motion of a trailer; detecting a first force applied to a kingpin; detecting an incline angle of the trailer; calculating a first target preload force opposite the direction of motion and inversely proportional to the incline angle; and in response to the first force falling below the first target preload force, triggering a motor to increase torque output opposite the direction of motion. The method further includes, during a second time period: detecting a second force applied to the kingpin; detecting a decline angle of the trailer; calculating a second target preload force opposite the direction of motion and inversely proportional to the decline angle; and in response to the second force falling below the second target preload force, triggering the motor to increase torque output opposite the direction of motion.