A safe braking method for ship lift with adjustable braking force curve according to external load

Abstract

The present invention provides a safe braking method for a ship lift with a braking force curve adjustable with external load, and the braking process is divided into five stages: the first stage: after the main hoist turns from normal speed to a preset overspeed limit, the braking system issues a brake-on command, and the main hoist speed continues to increase to the brake-on speed, at which time the braking force of the brake is 0; the second stage: after the brake is actually applied, the main hoist force increases from zero to the first-level braking force; the third stage: the main hoist force is maintained at the adjusted braking force to complete the braking of the main hoist, at which time the main hoist speed is reduced to 0 in the middle process, and the main hoist stops; the fourth stage: after the main hoist speed reaches 0 and stops, the braking force quickly increases to 100% braking force; the fifth stage: the brake maintains a full-pressure brake-on state. The present invention can realize precise control of braking acceleration and speed synchronization during the braking process, and complete precise and synchronous braking of the ship lift under different working loads at one time.

Description

Technical Field

[0001] The invention relates to the field of water conservancy, hydropower and navigation facility engineering, and in particular to a safe braking method for a ship lift with a braking force curve adjustable according to an external load. Background Art

[0002] As a navigation facility of a water conservancy hub, the wire rope hoist vertical ship lift is gaining more and more applications due to its advantages of adapting to the navigation of ships at high dams and rapid dam crossing. Its characteristic is that the weight of the structure, equipment and water body of the ship-carrying compartment is equal to the counterweight under the design water depth conditions. Therefore, the main hoist only needs to overcome the weight of the water body misloaded in the ship compartment, the inertia force of the system, the friction resistance of each moving pair, the wind resistance, the rigid resistance of the wire rope, the unbalanced weight of the ship compartment and the counterweight, etc., to drive the ship compartment to rise and fall.

[0003] In the wire rope winch vertical ship lift, the braking system of the main hoist or cabin drive system consists of a safety brake (group) and a working brake. The braking system is an important part to achieve the normal operation of the ship lift and ensure its safety. Under normal operation of the ship lift, the working brake system cooperates with the main electrical transmission control system to achieve normal start and stop of the ship lift; when the main hoist or drive system of the ship lift is powered off or multiple motors fail, the safety brake system realizes emergency braking of the system.

[0004] In traditional wire rope winch vertical ship lifts, the safety brake system generally presets the braking torque according to the design requirements and debugging conditions. The braking method adopts a fixed double-step braking torque curve, which is preset by the hydraulic system electro-hydraulic proportional relief valve and enforced under any load state. The braking system adopts a fixed braking curve to realize the start-stop action in various working conditions, and the ship lift is subjected to a large impact during emergency braking. After the central control station issues a braking command, the working brake implements forced braking according to the preset fixed braking torque curve through a single centralized control pump station. Although the braking system has the advantage of a simple system, it does not take into account the actual water depth height of the ship lift cabin at the moment of braking and the load size and direction of the main hoist. Therefore, the braking acceleration of the system is large at this time, which may cause emergency braking to impact the system. Summary of the invention

[0005] Aiming at the deficiencies of the above ship lift braking methods, the present invention provides a ship lift safety braking method with a braking force curve adjustable according to the external load.

[0006] A safe braking method for a ship lift with a braking force curve adjustable according to an external load, wherein the braking process of the braking force adjustment curve is divided into five stages:

[0007] Phase 1: After the main hoist speed reaches the preset overspeed limit from the normal speed, the brake system issues a brake-on command, and the main hoist speed continues to increase to the brake-on speed. At this time, the brake force is 0;

[0008] The second stage: After the brake is actually applied, the main hoisting machine braking force increases from zero to the first level braking force, and different braking torques are applied to complete the intelligent braking of the vertical ship lift;

[0009] The third stage: the main hoisting machine power is maintained at the adjusted braking force to complete the braking of the main hoist. At this time, the speed of the main hoist is reduced to 0 in the middle process, and the main hoist stops;

[0010] The fourth stage: after the main hoist speed reaches 0 and stops, the braking force increases rapidly to 100% braking force, i.e. the second level braking force, which corresponds to the rated braking force of the brake;

[0011] Stage 5: The brake remains fully pressed.

[0012] Furthermore, in the second stage, brake pressure is applied at a certain ramp rate until the speed encoder measures the desired deceleration. The brake pressure is adjusted in real time according to the closed-loop control principle based on the pressure feedback of the brake pipeline based on the load on the main hoist during each operation, to ensure that the ramp rate meets the set value, thereby achieving accurate first-level braking force.

[0013] Furthermore, the second-level braking force uses the rated torque of the motor as the working load, and the value is selected taking into account the design safety factor of the system.

[0014] In view of the deficiencies of existing ship lift braking methods, the present invention provides a technical method for applying different braking torques according to different load conditions and load sizes to complete intelligent braking of a vertical ship lift, and provides a corresponding braking force adjustment curve and braking process. In conjunction with the above-mentioned braking force adjustment curve and process, precise control of braking acceleration and speed synchronization are achieved during the braking process, and precise and synchronous braking of the ship lift under different load conditions is completed at one time. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the general arrangement diagram of the main hoist and brake;

[0016] Figure 2 It is the schematic diagram of brake cooperative control;

[0017] Figure 3 The present invention is a braking force adjustment curve diagram used in a ship lift safety braking method in which the braking force curve is adjustable with the external load. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The overall equipment layout and coordinated control principle diagram of the main hoist system and brake equipment of the present invention are as follows: Figure 1 , Figure 2 shown.

[0020] The main hoist of the ship lift shown is arranged in the main hoist room, and consists of 4 sets of winch lifting mechanisms and 1 set of mechanical synchronous shaft system. The main hoist is symmetrically arranged in 4 lifting point areas in the plane of the main engine room. The winch lifting mechanisms are connected by a mechanical synchronous shaft system. Each winch lifting mechanism consists of 2 sets of drum groups, 1 reducer, an AC variable frequency motor, 2 sets of safety brake groups, 1 set of working brake and other equipment.

[0021] The braking force adjustment curve of the main hoist braking system in the present invention is as follows: Figure 3 shown.

[0022] The braking force adjustment curve of the main hoist safety brake system shown is a complete braking process, which consists of brake release, lifting operation (brake in the released state), brake application, and shutdown (brake in the applied state).

[0023] according to Figure 1 , Figure 2 The main hoist is symmetrically arranged in four lifting point areas in the plane of the main engine room. The winch hoisting mechanisms are connected by a mechanical synchronous shaft system. Each winch hoisting mechanism consists of two sets of drum groups, one reducer, an AC variable frequency motor, two sets of safety brake groups, one set of working brakes and other equipment. The drum groups are arranged on both sides of the reducer, the working brake is arranged on the coupling with brake disc between the motor and the reducer, and the safety brake is arranged at the outer end of each drum. The safety brake and the working brake share the hydraulic pump station. The main hoist is equipped with two sets of hydraulic pump stations, which are arranged at both ends of the main hoisting room, respectively controlling the eight sets of safety brakes and four sets of working brakes of the four winch hoisting mechanisms; the main hoist of the second-level ship lift is equipped with one set of hydraulic pump stations, which is arranged in the center of the main hoisting room, controlling the eight sets of safety brakes and four sets of working brakes of the four winch hoisting mechanisms.

[0024] The normal stop brake of the main hoist and the rapid stop brake under general fault conditions are implemented through the electrical control system of the motor, and the stopping of the main hoist after stopping is undertaken by the safety brake system. When the electrical control system fails and cannot perform normal braking and rapid stop brake, the main hoist is implemented with emergency stop brake through the safety brake system. Under the condition of normal operation of the main hoist electrical transmission device, the normal stop brake and rapid stop brake of the winch hoisting mechanism are both executed by the motor-inverter. When the electrical transmission device fails and cannot implement normal stop brake and rapid brake, the winch hoisting mechanism is implemented with emergency stop brake by the safety brake system.

[0025] Through the above arrangement, the overall synchronous start-stop braking of the main hoist can be achieved.

[0026] The embodiment of the present invention provides a safe braking method for a ship lift with a braking force curve adjustable according to an external load. Figure 3 The braking force adjustment curve shown in the figure shows that the braking process is divided into five stages:

[0027] The first stage means that after the main hoist speed changes from normal speed to the preset overspeed limit, the brake system issues a brake-on command. At this time, due to the hysteresis effect of the brake, the speed of the main hoist continues to increase to the brake-on speed. At this time, the braking force of the brake is 0;

[0028] The second stage means that after the brake is actually applied, the main hoisting machine force increases from zero to the first level braking force (adjusting braking force) in a short period of time. The braking force is usually the rated lifting force in the traditional ship lift braking system. In order to achieve different braking torques according to different load conditions and load sizes to complete the intelligent braking of the vertical ship lift;

[0029] The present invention applies brake pressure at a certain ramp rate until the speed encoder measures the desired deceleration. Based on the pressure feedback of the brake pipeline from the load of each operation of the main hoist, the brake pressure can be adjusted in real time according to the closed-loop control principle to ensure that the ramp rate meets the set value, thereby achieving an accurate first-level braking force, which can be referred to as "adjusted braking force" here.

[0030] The third stage means that the main hoisting machine power is maintained at the adjusted braking force for a long time, and the braking of the main hoist is completed. At this time, the speed of the main hoist has been reduced to 0 in the middle process, and the main hoist stops;

[0031] The fourth stage means that after the main hoist speed reaches 0 and stops, the braking force quickly increases to 100% braking force, that is, the second-level braking force, which corresponds to the rated braking force of the brake; the second-level braking force takes the rated torque of the motor as the working load, and the value is taken into account the design safety factor of the system;

[0032] The fifth stage means that the brake remains in the fully pressed state.

[0033] The braking force regulation method shown above exists in two braking conditions:

[0034] A) Normal stop brake and quick stop brake

[0035] Under the condition that the main hoist electrical transmission device operates normally, the normal stop brake and quick stop brake of the winch hoisting mechanism are executed by the motor-inverter. When the motor speed is close to zero, the working brake is fully pressed on, and after a delay of several seconds, the safety brake is fully pressed on;

[0036] B) Emergency stop brake

[0037] When the electrical transmission device fails and cannot implement normal stopping and rapid braking, the winch hoisting mechanism implements emergency stopping braking by the safety brake system. First, the working brake is adjusted according to the real-time external load size and direction. After the working brake is applied for several seconds, the safety brake is fully pressed.

[0038] Through the above braking scheme, the power curve of the main hoisting mechanism can be adjusted according to the external load.

[0039] The braking force curve adjustment principle of the present invention:

[0040] In view of the requirement that the main hoist braking force curve can be adjusted with the external load, the system is equipped with the main hoist electrical transmission control system and the brake hydraulic station control system, and a multi-variable composite position, speed, and torque three-closed-loop hybrid control scheme is selected. Its basic principles are as follows:

[0041] A) Steady state

[0042] Torque balancing control method:

[0043] When the system adopts torque balancing control mode, the transmission device works in a master / multiple slave mode, and both the master drive and the slave drive work in the speed closed-loop mode. The torque setting of the master drive is sent to the slave drive through the transmission device control unit network at the same time. The compensation setting of the slave drive will be determined according to the output after the adjustment of the torque error between the master drive and the corresponding slave drive, so that the torque of the corresponding slave drive is compensated and adjusted, thereby maintaining the torque balance of the system.

[0044] Due to possible system errors and inherent errors in the transmission machinery during long-term operation of the system, the control system needs to have an accurate dynamic calibration function to ensure that the internal reference of the control system is consistent with the external actual reference.

[0045] After the precise positioning begins, the system collects the actual position feedback signals of each driving point in real time by setting up the ship carriage travel deviation and point stop detection device, ship carriage dynamic level detection device, etc., and sends them to the main hoist electrical transmission control system together with the target positioning position. The transmission control system controls the acceleration and deceleration and position difference compensation according to the optimal operating trajectory to form precise positioning control.

[0046] Generation of speed reference and position reference:

[0047] A signal given generator is set at the transmission control station to generate the cabin running position and running speed at the current moment according to the cabin current position, running target position and set running speed, and transmit it to the running transmission device in real time as position given and speed given. A complete running process should be an S-shaped speed curve. The work of this generator can change the running operation conditions by position verification signal, normal stop command, emergency stop command, so as to generate corresponding running curve, stop curve or interrupt operation.

[0048] B) Fault adjustment status:

[0049] When a serious fault occurs in the system, such as a motor or transmission failure or a mechanical transmission shaft breakage, the system will enter a fault state. At this time, the system will automatically complete the master-slave switch according to the fault state and form a new control structure.

[0050] C) Fault parking status:

[0051] If more than one motor (or more than one transmission device) of the main hoist fails, or the system speed / position error seriously exceeds the limit, the system will start the emergency stop / safety stop procedure and the system will enter a fault stop.

[0052] In actual operation, the system will determine which of the above operating states to work in based on the operating conditions, mechanical structure characteristics and the settings of each balance threshold. If all conditions are ideal, the system can operate in a stable state for a long time, while other states are only used to provide safety for the system. The above system solution can always maintain the system's requirements for the main lifting brake force curve.

[0053] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A safe braking method for a ship lift with a braking force curve adjustable according to external load, It is characterized in that The braking process of the braking force curve is divided into five stages: Phase 1: After the main hoist speed reaches the preset overspeed limit from the normal speed, the brake system issues a brake-on command, and the main hoist speed continues to increase to the brake-on speed. At this time, the brake force is 0; The second stage: After the brake is actually applied, the main hoisting machine braking force increases from zero to the first level braking force, and different braking torques are applied to complete the intelligent braking of the vertical ship lift; The third stage: the main hoisting machine power is maintained at the adjusted braking force to complete the braking of the main hoist. At this time, the speed of the main hoist is reduced to 0 in the middle process, and the main hoist stops; Stage 4: After the main hoist speed reaches 0 and stops, the braking force quickly increases to 100% braking force, that is, the second-level braking force, which corresponds to the rated braking force of the brake; Stage 5: The brake remains fully pressed; In the second stage, brake pressure is applied at a certain ramp rate until the speed encoder measures the desired deceleration. The brake pressure is adjusted in real time according to the closed-loop control principle based on the pressure feedback of the brake pipeline according to the load on the main hoist during each operation to ensure that the ramp rate meets the set value, thereby achieving accurate first-level braking force.

2. The safe braking method for a ship lift with a braking force curve adjustable according to the external load as claimed in claim 1, Features: The second-level braking force takes the rated torque of the motor as the working load, and the value is selected taking into account the design safety factor of the system.

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