Control method for limited operation of crown block in complex area

Abstract

The invention discloses a control method for limited operation of a crown block in a complex area, which comprises the following steps of: S1, establishing a three-dimensional coordinate system, and selecting an original point, a cart direction as an X axis, a trolley direction as a Y axis and a lifting direction as a Z axis; s2, based on the three-dimensional coordinate system in the step S1, three-dimensional coordinates of a lifting hook are obtained; and S3, automatic stepless speed reduction of the cart and the trolley is achieved, and speed and position limitation is conducted on the multiple complex areas. According to the invention, the speed and position limitation of the complex region is realized, and the region division method can realize the region limitation of unlimited quantity. According to the invention, the functions of automatic stepless speed reduction and stopping can be realized when the robot moves to the regional boundary. In addition, step speed reduction can be achieved, and the speed is reduced by one gear when the distance is smaller than the gear speed reduction distance only by corresponding the distance to each gear. Fixed point position sensors such as a proximity switch are replaced, and the area limiting function is achieved; and limiting areas and limiting conditions can be customized. The method is not limited to manual operation of the crown block, and is more suitable for the unmanned crown block with distance measuring equipment.

Description

Technical Field

[0001] The invention relates to the field of overhead crane control, and in particular to a control method for restricting operation of an overhead crane in a complex area. Background Art

[0002] Overhead crane is an industrial lifting equipment, and most factories use overhead crane to move heavy objects. Generally, it has three major mechanisms: a trolley, a car, and a hoist. Its main functional component, the hook or sling, can move up and down, forward and backward, and left and right in three dimensions with the three mechanisms.

[0003] Carts and trolleys move on tracks with their wheels, and like cars, they usually slow down and stop. Although direct braking at high speed will not cause rollover, it has greater inertia and slides farther. More importantly, the wire rope is flexible, and it will swing and sway during movement and when stopping. Sudden braking is more likely to cause a large swing, and the hanging heavy objects are more likely to lose control and hit machinery, equipment, walls and other avoidable objects. Therefore, overhead crane operators generally need to observe the environment carefully, estimate the swing range and deceleration distance, reduce the gear and gradually stop. In some complex environments with many obstacles, running very slowly can reduce the probability of collision, but the efficiency is very low.

[0004] In the past, in order to restrict operation within a fixed area or prevent collisions during external operation, such as limiting speed and position, proximity switches or non-contact fixed-point switches were used to trigger relays, which were often installed near four points in a rectangular area. However, the proximity switch body or its sensing component is installed on a welded angle steel and is fixed at one point. After the initial debugging is completed, the position cannot be adjusted. If the area changes, its function will fail. And it is not just at the boundary line of the restricted area, but must also include the deceleration distance. However, the deceleration distances of different gear speeds are not the same, and can only be set according to the deceleration distance of the highest gear. In this case, a long space must be reserved. For some narrow restricted areas, the range in which the overhead crane can move will become very small.

[0005] To limit the speed or position of multiple complex areas, a large number of proximity switches are required. However, proximity switches are vulnerable parts and are prone to failure. Once damaged, the PLC will not be able to correctly identify the area, causing system failure. Summary of the invention

[0006] In order to solve the problem in the background technology, the present invention proposes a control method for restricting the operation of an overhead crane in a complex area, which can accurately restrict the operation of the overhead crane in a complex area and improve the safety of the operation of the overhead crane.

[0007] A control method for restricting operation of an overhead crane in a complex area, comprising:

[0008] S1. Establish a three-dimensional coordinate system and select the origin, with the trolley direction as the X-axis, the trolley direction as the Y-axis, and the lifting direction as the Z-axis;

[0009] S2. Based on the three-dimensional coordinate system in step S1, obtain the three-dimensional coordinates of the hook;

[0010] S3. Realize automatic stepless deceleration of large and small vehicles, and set speed and position limits for multiple complex areas.

[0011] In step S2, the three-dimensional coordinates of the hook are obtained, specifically:

[0012] 201) Detecting the hook height: An absolute encoder is installed on the concentric shaft on one side of the reel or on the gear shaft meshing with the shaft to detect the rotation angle and calculate the current height of the hook;

[0013] 202) Detect the position of the trolley and the carriage: Use laser distance measurement, install a laser distance meter at the end of the track, and install a reflective film on the overhead crane to measure the distance.

[0014] Furthermore, the positions of the trolley and the carriage can be detected by using encoders, encoder rulers, and Gray busbars.

[0015] Devices such as the absolute value encoder or laser rangefinder of the present invention can receive the position data of the hook through programmable controller (PLC) communication.

[0016] In step S3, the vehicle automatically and continuously decelerates, specifically:

[0017] Since overhead cranes are usually step-by-step speed regulators, five fixed speeds are set, and the trolley running speeds of gears 1 to 5 are V D1 、V D2 、V D3 、V D4 、V D5 According to the crane parameters, the rated speed V of the crane can be obtained. DA , then according to the linear relationship, we can know that 0~50Hz corresponds to 0~V D5 .

[0018] Furthermore, in order to realize automatic stepless speed regulation of the vehicle, the following are performed:

[0019] 303) Calculate the maximum speed at which it can run:

[0020] The critical situation of running at the highest speed is that the distance = acceleration running distance + deceleration running distance;

[0021] Accelerate from zero speed to maximum speed V DA , and then immediately from V DA decelerate to zero speed, this operation process is at the maximum speed V DAThe critical point of operation, the running distance is D dl =1 / 2(T Da +T Dd )*V DA ; Among them, T Da is the acceleration time; T Dd is the deceleration time;

[0022] If the distance difference D abs ≥D dl No speed limit is required;

[0023] If the distance difference D abs <D dl When the distance calculation formula is still D abd =1 / 2(T Da +T Dd )*V D , inversely infer the speed At this time V D Must be smaller than V DA ;

[0024] Therefore, according to the distance difference D at the start gear abs , calculate the speed limit

[0025] After the startup is completed, this value is no longer calculated, and the speed is directly controlled to V throughout the process Dm ; If V Dm >V DA , then take V Dm =V DA ;

[0026] 304) Calculate the deceleration speed:

[0027] Calculate the maximum deceleration speed based on the real-time distance difference It will gradually decrease as the distance difference decreases, controlling the speed V D =V Dd ;

[0028] The control strategy is obtained:

[0029] 1) If V Dd >V Dm , control speed V D =V Dm ; When V Dd <V Dm After that, V D =V Dd ; If V Dd ≤V Dm , control speed V D =V Dd ;

[0030] 2) If the operator sets the gear speed V DF <V D , then the operator's output V D =V DF , this function is an auxiliary function, subject to the operator.

[0031] In the present invention, the automatic stepless deceleration control of the trolley is the same as the automatic stepless deceleration control of the large vehicle.

[0032] In step S3, when the overhead crane hook is in a certain area, it moves forward, backward, left and right to determine the restrictions of the adjacent area. When it needs to rise to a certain height to pass, the height will be used as a condition first. When it is lower than the specified height, it will automatically slow down and stop when moving towards the boundary without crossing the boundary. When entry is prohibited, the height will no longer be used as a condition. Regardless of the height, it will automatically slow down and stop when moving towards the boundary.

[0033] The present invention has the following advantages:

[0034] 1. The present invention realizes speed and position restrictions in complex areas, and its area division method can realize unlimited number of area restrictions.

[0035] 2. The present invention realizes the function of automatically steplessly decelerating and stopping when moving toward the area boundary. It can also realize step-by-step deceleration, which only requires matching the distance with each gear, and reducing one gear if the distance is less than the gear deceleration distance.

[0036] 3. The present invention replaces fixed point sensors such as proximity switches to achieve area restriction functions; restricted areas and restriction conditions can be customized.

[0037] 4. The present invention is not limited to manually operated overhead cranes, but is more applicable to unmanned overhead cranes equipped with distance measuring equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the schematic diagram and coordinate system of the overhead crane workshop;

[0039] Figure 2 is a graph of the relationship between speed and time;

[0040] Figure 3 This is the flow chart of automatic stepless deceleration for large vehicles;

[0041] Figure 4 It is a schematic diagram of plane area division;

[0042] Figure 5 This is a flow chart of area division and restriction. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0044] Example 1

[0045] A control method for restricting operation of an overhead crane in a complex area comprises the following steps:

[0046] Step 1. Establish a three-dimensional coordinate system with the workshop where the overhead crane is located as the model, and select the origin, where the direction of the crane is the X-axis, the direction of the trolley is the Y-axis, and the lifting direction is the Z-axis;

[0047] Step 2. Based on the three-dimensional coordinate system in step 1, obtain the three-dimensional coordinates of the hook;

[0048] Includes: 1) Detecting the height of the hook, installing an absolute encoder on the concentric shaft on one side of the drum or on the gear shaft meshing with the shaft to detect the rotation angle and convert the current height. 2) Detecting the position of the trolley and the carriage, using laser distance measurement, installing a laser distance meter at the end of the track, and installing a reflective film on the overhead crane, the distance can be measured. Other measurement methods such as encoders, encoder rulers, Gray busbars, etc. can also be used. Devices such as the absolute encoder or laser distance meter in this solution can receive position data through programmable controller (PLC) communication.

[0049] like Figure 1 As shown, the current coordinate of the trolley is D, the current coordinate of the small car is V, and the current coordinate of the hoist is H.

[0050] Step 3. Realize automatic stepless deceleration of large and small vehicles;

[0051] In this solution, firstly, automatic stepless deceleration can be achieved in the process of approaching the target.

[0052] Since overhead cranes are usually step-by-step speed regulators, five fixed speeds are set, and the trolley running speeds of gears 1 to 5 are V D1 、V D2 、V D3 、V D4 、V D5 According to the crane parameters, the rated speed V of the crane can be obtained. DA , then according to the linear relationship, we can know that 0~50Hz corresponds to 0~V D5 .

[0053] However, in this scheme, stepless speed regulation can be achieved, which is specifically the following two steps.

[0054] The first step is to calculate the maximum speed at which it can run.

[0055] The critical situation of being able to run at the highest speed is that the distance = acceleration distance + deceleration distance. Figure 2 As shown, it accelerates from zero speed to the maximum speed V DA , and then immediately from V DA decelerate to zero speed, this operation process is at the maximum speed V DA The critical point of operation, the running distance is D dl =1 / 2(T Da +T Dd )*V DA ; Therefore, the distance difference D abs ≥D dl No speed limit is required.

[0056] Distance difference D abs <D dl When the distance calculation formula is still D abs =1 / 2(T Da +T Dd )*V D , inversely infer the speed At this time V D Must be smaller than V DA .

[0057] Therefore, according to the distance difference D at the start gear abs , calculate the speed limit After the startup is completed, this value is no longer calculated, and the speed is directly controlled to V throughout the process Dm (If V Dm >V DA , then take V Dm =V DA ).

[0058] Step 2: Calculate the deceleration speed

[0059] Calculate the maximum deceleration speed based on the real-time distance difference It will gradually decrease as the distance difference decreases, controlling the speed V D =V Dd .

[0060] The control strategy is obtained:

[0061] (1) If V Dd >V Dm , control speed V D =V Dm , when V Dd <V Dm After that, V D =V Dd ; If V Dd ≤V Dm , control speed V D =V Dd .

[0062] (2) If the operator sets the gear speed V DF <V D , then the operator's output V D =V DF This function is an auxiliary function and is subject to the operator.

[0063] (3) The same is true for the car speed control. The automatic stepless deceleration flow chart is as follows: Figure 3 shown.

[0064] Step 4. Implement speed and location restrictions for multiple complex areas.

[0065] exist Figure 1 The layout shown in the figure is a stamping equipment workshop in a certain automobile factory, where restrictions need to be set in the middle and some areas.

[0066] First, the actual workshop layout is analyzed and a two-dimensional plan is generated. According to the rectangular partition principle, it is divided into the following 9 areas Q1~Q9, see Figure 4 .

[0067] Divide the area according to the boundary line and determine the conditions of which area you are currently in:

[0068] 1) When D4<D, it is in Q1, and the area height is 0;

[0069] 2) When D3<D<D4,

[0070] If V1<V<V4, it is in Q2 and the area height is H2;

[0071] If V4<V, it is in Q3 and the area height is 0;

[0072] If V<V1, it is in Q4 and the area height is 0;

[0073] 3) When D2<D<D3

[0074] If V2<V<V3, it is in Q5 and the area height is H5;

[0075] If V4<V, it is in Q6 and the area height is 0;

[0076] If V<V1, it is in Q7 and the area height is 0;

[0077] 4) When D1<D<D2, it is in Q8 and the area height is H8;

[0078] 5) When D<D1, it is in Q9 and the area height is 0;

[0079] Among them, Q5 is the stamping equipment, Q2 is the stamping equipment control room, Q8 is the isolation wall, H5, H2> overhead crane lifting height, the overhead crane cannot pass through, it can be seen that Q2, Q5 are impossible to reach areas. It should be noted that when hanging the hoist or the object being hoisted, height compensation should be performed.

[0080] The specific restriction methods are as follows:

[0081] When the overhead crane hook is in a certain area, it moves forward, backward, left and right to determine the restrictions of the adjacent area. When it needs to rise to a certain height to pass, the height will be used as a condition first. When it is lower than the specified height, it will automatically slow down and stop when moving towards the boundary without crossing the boundary. When entry is prohibited, the height will no longer be used as a condition. Regardless of the height, it will automatically slow down and stop when moving towards the boundary.

[0082] In the case of the present invention, if in area Q7: 1) the front is Q5, because the hook cannot be higher than H5, it is forbidden to enter Q5, then the boundary is V2, the distance difference V abs = V2-V, according to the automatic stepless deceleration method of the present invention, the speed will be automatically limited until it stops, ensuring that the limit V2 is not crossed; 2) There is a wall behind and it cannot pass, the limit is 0, and the distance difference V avs =V2-0, according to the automatic stepless deceleration method of the present invention, the speed will be automatically limited until it stops to ensure that it does not cross the boundary 0; 3) To the left is Q8, only when the hook rises to H>H8, can it cross the boundary D2 to reach the Q8 area, otherwise according to the automatic stepless deceleration method of the present invention, the speed will be automatically limited until it stops to ensure that it does not cross the boundary D2; 4) To the right are Q2 and Q4, the height H2 of the Q2 area is greater than the maximum lifting height, and this area is prohibited from entering. When V1<V<V2, according to the automatic stepless deceleration method of the present invention, the speed will be automatically limited until it stops to ensure that it does not cross the boundary D3; when V<V1, there is no restriction, and it can cross the boundary D3 to enter the Q4 area. The restriction principles of areas Q1, Q3, Q6, and Q9 are consistent with those of area Q7. See the flow chart Figure 5 .

[0083] In the case of the present invention, if in area Q8: 1) To the right are Q5, Q6, Q7. When V<V2 or when V3<V<V5, you can directly cross boundary D2 to enter Q6 or Q7; when V2<V<V3, it is forbidden to enter area Q5 and is automatically restricted to boundary D2. 2) The ends of the front and rear directions are walls, and it is forbidden to cross boundaries 0 and V5; 3) The end to the left is a wall, and it is forbidden to cross boundary 0.

[0084] In the case of the present invention, it is impossible to enter the areas Q2 and Q5. The above limit values ​​V1, V2, V3, V4, V5, D1, D2, D3, D4, and D5 can be adjusted by the on-site operator according to the actual situation after debugging.

[0085] Features of the present invention: 1. To renovate old grab cranes, only an absolute encoder or other distance measuring sensor needs to be added, and the area restriction function can be realized through software; 2. The restricted area can be customized, and the scope and number are not limited; 3. Anti-collision in complex areas is realized, and manual operation is assisted, which greatly improves efficiency; 4. The boundary of the area can be adjusted according to the site requirements or the change of driving parameters, and the boundary value can be completed by the operator; 5. It is not limited to overhead cranes with stepless speed regulation, but can also be used for overhead cranes that can only run at fixed gear speeds, such as contactor cutting resistance, voltage regulation and speed control, inverter terminal control, etc.

[0086] Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for restricting the operation of an overhead crane in a complex area, characterized in that include: S1. Establish a three-dimensional coordinate system and select the origin, with the trolley direction as the X-axis, the trolley direction as the Y-axis, and the lifting direction as the Z-axis; S2. Based on the three-dimensional coordinate system in step S1, obtain the three-dimensional coordinates of the hook; S3. Realize automatic stepless deceleration of large and small vehicles, and set speed and position limits for multiple complex areas.

2. According to claim 1, a control method for complex area restricted operation of an overhead crane is characterized in that: In step S2, the three-dimensional coordinates of the hook are obtained, specifically: 201) Detecting the hook height: An absolute encoder is installed on the concentric shaft on one side of the reel or on the gear shaft meshing with the shaft to detect the rotation angle and calculate the current height of the hook; 202) Detect the position of the trolley and the carriage: Use laser distance measurement, install a laser distance meter at the end of the track, and install a reflective film on the overhead crane to measure the distance.

3. According to claim 2, a control method for restricting operation of an overhead crane in a complex area is characterized in that: The position of the trolley and carriage is detected by using encoder, encoder ruler and Gray busbar measurement methods.

4. According to claim 1, a control method for restricting operation of an overhead crane in a complex area is characterized in that: In step S3, the vehicle automatically and continuously decelerates, specifically: Since overhead cranes are usually step-by-step speed regulators, five fixed speeds are set, and the trolley running speeds of gears 1 to 5 are V D1 、V D2 、V D3 、V D4 、V D5 According to the crane parameters, the rated speed V of the crane can be obtained. DA , then according to the linear relationship, we can know that 0~50Hz corresponds to 0~V D5 ; In order to realize automatic stepless speed regulation of the truck, the following two steps are specifically required: 301) Calculate the maximum speed at which it can run: The critical situation of running at the highest speed is that the distance = acceleration running distance + deceleration running distance; Accelerate from zero speed to maximum speed V DA , and then immediately from V DA decelerate to zero speed, this operation process is at the maximum speed V DA The critical point of operation, the running distance is D dl =1 / 2(T Da +T Dd )*V DA ; Among them, T Da is the acceleration time; T Dd is the deceleration time; If the distance difference D abs ≥D dl No speed limit is required; If the distance difference D abs <D dl When the distance calculation formula is still D abs =1 / 2(T Da +T Dd )*V D , inversely infer the speed At this time V D Must be smaller than V DA ; Therefore, according to the distance difference D at the start gear abs , calculate the speed limit After the startup is completed, this value is no longer calculated, and the speed is directly controlled to be V throughout the process Dm ; If V Dm >V DA , then take V Dm =V DA ; 302) Calculate the deceleration speed: Calculate the maximum deceleration speed based on the real-time distance difference It will gradually decrease as the distance difference decreases, controlling the speed V D =V Dd ; The control strategy is obtained: 1) If V Dd >V Dm , control speed V D =V Dm ; When V Dd <V Dm After that, V D =V Dd ; If V Dd ≤V Dm , control speed V D =V Dd ; 2) If the operator sets the gear speed V DF <V D , then the operator's output V D =V DF , this function is an auxiliary function, subject to the operator.

5. According to claim 1, a control method for complex area restricted operation of an overhead crane is characterized in that: In step S3, when the overhead crane hook is in a certain area, it moves forward, backward, left and right to determine the restrictions of the adjacent area. When it needs to rise to a certain height to pass, the height will be used as a condition first. When it is lower than the specified height, it will automatically slow down and stop when moving towards the boundary without crossing the boundary. When entry is prohibited, the height will no longer be used as a condition. Regardless of the height, it will automatically slow down and stop when moving towards the boundary.

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