A method for controlling the rotation speed of a servo motor

Abstract

The application relates to the technical field of motor control, and discloses a rotating speed control method based on a servo motor, which comprises the following steps: judging whether the transmission efficiency is normal, judging the cause of the abnormal transmission efficiency when the transmission efficiency is abnormal, using different simulation sets according to the abnormal cause, determining the final adjusted rotating speed and the speed regulation mode, and the rotating speed control method based on the servo motor can judge whether the transmission efficiency reduction is caused by the increased friction between mechanical parts due to the lack of lubrication or improper lubrication of the mechanical parts or the increased load of the goods when passing through the supporting roller, and the rotating speed of the servo motor is adjusted according to the cause of the transmission efficiency reduction, the predetermined production efficiency is maintained, the equipment can be maintained in time after the production cycle is completed as soon as possible, and the production cost increase caused by the maintenance during the production is avoided.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, specifically to a speed control method based on a servo motor. Background Technology

[0002] Servo motor-based speed control methods cover a wide range of fields, including motor technology, control theory, sensor technology, and drive technology. They typically involve precise control of the motor to achieve the required speed. Due to their high precision, high response speed, and high reliability, servo motors are widely used in automation systems and robotics. Commonly used servo motor speed control methods include open-loop control, closed-loop control (feedback control), PWM (pulse width modulation) based control, stepper control, fuzzy control, tuning and optimization, real-time monitoring and fault diagnosis, and the implementation of control algorithms (software implementation). These methods are diverse and flexible, allowing for the selection of appropriate methods based on specific needs and application scenarios, significantly improving the performance of the servo motor and the stability of the system.

[0003] Existing servo motor-based speed control methods cannot determine whether the reduced transmission efficiency of the conveyor line is due to insufficient or improper lubrication of mechanical parts causing increased friction between the parts, or due to increased load caused by the items passing over the rollers. Therefore, they cannot adjust the servo motor speed accordingly to reduce production efficiency based on the cause of the reduced transmission efficiency, thus limiting their practicality. Summary of the Invention

[0004] This invention provides a speed control method based on a servo motor, which helps to solve the problems mentioned in the background art.

[0005] This invention provides the following technical solution: a speed control method based on a servo motor, comprising:

[0006] Determine if the transmission efficiency is normal;

[0007] If the transmission efficiency is normal, the motor is controlled to maintain the initial speed and continuously acquire transmission efficiency.

[0008] If the transmission efficiency is abnormal, the transmission line will be divided into special areas and ordinary areas.

[0009] Obtain the current load torque of the motor, denoted as . ;

[0010] Obtain the rated load torque of the motor, denoted as . ;

[0011] Obtain the theoretical load torque of the motor, denoted as . ;

[0012] Calculate the load torque variation in a specific region:

[0013] ;

[0014] like If so, the transmission efficiency in the special area is determined to be normal;

[0015] like If the transmission efficiency is abnormal in a specific area, the load model is obtained, and the adjustment speed is extracted. ;

[0016] Calculate the load torque variation in the normal region:

[0017] ;

[0018] like If so, the transmission efficiency is determined to be normal within the normal range;

[0019] like If the transmission efficiency is abnormal within the normal range, a friction model is obtained, and the adjustment speed is extracted. ;

[0020] The control motor adjusts its speed from the initial speed to the adjusted speed and continuously obtains transmission efficiency.

[0021] As an optional solution to the servo motor-based speed control method of the present invention, the step of determining whether the transmission efficiency is normal specifically involves:

[0022] The current transmission efficiency of the transmission line is calculated using the efficiency formula, and denoted as . :

[0023] ;

[0024] In the efficiency formula, The current output power of the transmission line is as follows:

[0025] ;

[0026] in, This is the current transmission speed. It is the initial transmission efficiency. It is load-bearing capacity;

[0027] load capacity The specific formula is:

[0028] ;

[0029] in, It is the current load torque of the motor. It is the radius of the mechanical part;

[0030] In the efficiency formula, The current input power of the transmission line is as follows:

[0031] ;

[0032] in, It is the input torque of the servo motor. It is the angular velocity of the servo motor;

[0033] Input torque The specific formula is:

[0034] ;

[0035] in, It is the current load torque of the motor. It is frictional torque;

[0036] Among them, frictional torque The specific formula is:

[0037] ;

[0038] in, It is load-bearing capacity. It is the radius of the mechanical part. It is the coefficient of friction;

[0039] angular velocity The specific formula is:

[0040] ;

[0041] in, This is the current speed of the servo motor;

[0042] The difference in transmission efficiency is calculated and denoted as . :

[0043] ;

[0044] in, It is the initial transmission efficiency;

[0045] Set a threshold for transmission efficiency variation, denoted as . ;

[0046] like If so, the transmission efficiency is considered normal;

[0047] like If so, the transmission efficiency is determined to be abnormal.

[0048] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the load model includes determining the load torque in the normal region, specifically:

[0049] Obtain all the weights of the items and form a weight set;

[0050] Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ;

[0051] Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ;

[0052] Calculate the gravitational torque for the weight of each item in the weight set, denoted as . :

[0053] ;

[0054] in, It is the radius of the mechanical part;

[0055] Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ;

[0056] Obtain angular acceleration, denoted as ;

[0057] Calculate the moment of inertia of each item in the weight set, denoted as . :

[0058] ;

[0059] Calculate the load torque in the general region for each item's weight in the weight set, denoted as . :

[0060] .

[0061] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the load model includes determining the load torque in a specific region, specifically:

[0062] Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ;

[0063] Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ;

[0064] Calculate the gravitational torque for the weight of each item in the weight set, denoted as . :

[0065] ;

[0066] in, It is the radius of the mechanical part;

[0067] Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ;

[0068] Obtain angular acceleration, denoted as ;

[0069] Calculate the moment of inertia of each item in the weight set, denoted as . :

[0070] ;

[0071] Calculate the material gravity component of the weight of each item in the weight set, denoted as . :

[0072] ;

[0073] in, It is the material filling rate. It is the density of the material. It is the cross-sectional area of ​​the circular tube conveyor belt. It is gravitational acceleration;

[0074] Calculate the conveyor belt forming force component for the weight of each item in the weight set, denoted as . :

[0075] ;

[0076] in, It is the bending moment generated by the stress in the conveyor belt cross section. It is the chord length corresponding to the bending moment;

[0077] Calculate the conveyor belt gravity component for the weight of each item in the weight set, denoted as . :

[0078] ;

[0079] in, It is the width of the conveyor belt. It is the spacing between the idler rollers. It refers to the thickness of the conveyor belt. It is the density of the conveyor belt. It is gravitational acceleration;

[0080] Calculate the roller contact torque for the weight of each item in the weight set, denoted as . :

[0081] ;

[0082] Calculate the load torque in the general region for each item's weight in the weight set, denoted as . :

[0083] .

[0084] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the load model includes determining the adjustment speed of the servo motor under different load torques, specifically:

[0085] Obtain the frictional torque for each item in the weight set, denoted as . ;

[0086] Obtain the load torque for each item in the weight set, denoted as . ;

[0087] Calculate the output torque of the servo motor for each item's weight in the weight set, denoted as . :

[0088] ;

[0089] in, This refers to the rated torque of the servo motor.

[0090] Obtain all transmission speeds and form a speed set;

[0091] Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ;

[0092] Calculate the angular velocity of the servo motor when the conveyor line operates at the target conveyor speed, for each item in the weight set, and denote it as . :

[0093] ;

[0094] in, It is the radius of the mechanical part;

[0095] Calculate the transmission efficiency of the conveyor line for each item's weight in the weight set, denoted as . :

[0096] ;

[0097] in, It is the input voltage of the servo motor. It is the input current of the servo motor;

[0098] Calculate the torque required by the servo motor for each item weight in the weight set, denoted as . :

[0099] ;

[0100] Obtain the rated power of the servo motor, denoted as... ;

[0101] Calculate the required adjustment speed of the servo motor when the conveyor line transmits the items at different speeds for each item's weight in the weight set, denoted as . :

[0102] .

[0103] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the friction model includes determining the friction coefficient of each mechanical component under different lubrication levels, specifically:

[0104] Acquire all mechanical components along the transmission line to form a component set;

[0105] Each mechanical component in the component set is identified as the target component;

[0106] Define the set of lubrication states of the target component, denoted as... :

[0107] ;

[0108] All lubrication levels corresponding to each element in the simulated lubrication state set:

[0109] ;

[0110] Determining the coefficient of friction using a relational function. and The relationship between lubrication levels:

[0111] ;

[0112] in, It is the maximum coefficient of friction under unlubricated conditions. It is the coefficient of friction under moderate lubrication. It is a constant, representing the intensity of the effect of lubrication degree on the coefficient of friction;

[0113] Calculate the overall coefficient of friction of the transmission line for each mechanical component under different lubrication levels, denoted as . :

[0114] ;

[0115] in, It is the first The coefficient of friction of a mechanical component It is the first The input torque of each mechanical component It represents the total number of mechanical parts in the transmission line.

[0116] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the friction model includes determining the transmission efficiency under different friction coefficients, specifically:

[0117] Let an initial efficiency formula be defined:

[0118] ;

[0119] in, It is the initial output torque. It is the initial input torque;

[0120] Obtain the overall coefficient of friction of the transmission line for each mechanical component in the component set under different lubrication levels. ;

[0121] Calculate the overall frictional torque, denoted as :

[0122] ;

[0123] in, It is the input torque;

[0124] Calculate the actual output torque, denoted as :

[0125] ;

[0126] It is a constant related to the mechanical structure;

[0127] Calculate the transmission efficiency (considering frictional losses) of each mechanical component in the transmission line under different lubrication levels, denoted as . :

[0128] .

[0129] As an optional solution to the servo motor-based speed control method of the present invention, wherein: obtaining the friction model includes determining the adjustment speed of the servo motor for each mechanical component in the transmission line under different lubrication levels, specifically:

[0130] Obtain all transmission speeds and form a speed set;

[0131] Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ;

[0132] To obtain the transmission efficiency loss of each mechanical component in the transmission line under different lubrication levels. ;

[0133] Calculate the motor's adjustment speed for each mechanical component in the transmission line under different lubrication levels, when the transmission line operates at different target speeds, and denote it as . :

[0134] ;

[0135] in, It is the radius of the mechanical part.

[0136] As an optional solution to the servo motor-based speed control method of the present invention, the division of the transmission line into special areas and ordinary areas specifically includes:

[0137] Obtain the direction in which the item is moving along the teleportation path and set it as the target direction;

[0138] Arbitrarily extract two adjacent idlers on the conveyor line and designate them as the front idler and the rear idler according to the target direction;

[0139] Extract the center points of the front idler roller and the rear idler roller respectively, and designate them as the front center point and the rear center point;

[0140] Connect the front center point and the back center point to form an analysis line;

[0141] Extract the midpoint of the analysis line and set it as the analysis midpoint;

[0142] Replace the rear idler with the front idler, and extract its other adjacent idler, which is then identified as the rear idler.

[0143] The midpoint between the front and rear idlers is extracted again and identified as the second midpoint.

[0144] Collect all the locations of the item as it moves from the midpoint of the analysis to the second midpoint, forming a location set;

[0145] The idler roller between the midpoint of the analysis and the second midpoint is identified as the analysis idler roller;

[0146] Extract all elements in the location set that have contact surfaces with the item, conveyor belt, and analysis roller, forming a contact set;

[0147] Extract and analyze the element corresponding to the center point of the idler roller in the contact set, and define it as the center element;

[0148] Extract the two elements in the contact set that are farthest from the center element, and designate them as the front tangent point and the back tangent point according to the target direction;

[0149] Using the front tangent point and the back tangent point as origins, draw parallel lines to the axis of the analysis roller, and define them as the front tangent line and the back tangent line, respectively.

[0150] The area on the conveyor line between the front tangent and the rear tangent of the analysis roller is defined as a special area;

[0151] The area on the conveyor line between the rear tangent of the front idler roller and the front tangent of the rear idler roller is defined as the normal area.

[0152] The present invention has the following beneficial effects:

[0153] 1. This servo motor-based speed control method analyzes the transmission efficiency of the current transmission line, determines the difference between the current transmission efficiency and the predetermined initial transmission efficiency, and judges whether the difference is within a reasonable threshold range. This helps determine if the transmission efficiency is abnormal. If the transmission efficiency is abnormal, the method determines the cause of the abnormality and adjusts the speed of the servo motor accordingly to maintain the predetermined transmission efficiency and production efficiency. This allows the equipment to complete the production cycle as quickly as possible and perform timely maintenance, avoiding increased production costs due to power outages during maintenance.

[0154] 2. This servo motor-based speed control method, when the transmission efficiency of the conveyor line decreases, divides the conveyor line into zones to determine the area on the conveyor line to which the abnormal transmission efficiency belongs. It then determines whether the decrease in transmission efficiency is due to increased friction between mechanical parts caused by lack of lubrication or improper lubrication, or due to increased load caused by the items passing over the rollers. Based on the cause of the decrease in transmission efficiency, the speed of the servo motor is adjusted accordingly to maintain the predetermined production efficiency. This allows the equipment to complete the production cycle as quickly as possible and perform timely maintenance, avoiding increased production costs caused by power outages during maintenance.

[0155] 3. This servo motor-based speed control method addresses the issue of decreased transmission efficiency in the conveyor line. If the reduced efficiency is due to insufficient or improper lubrication of mechanical components leading to increased friction, a friction model is obtained. This involves simulating different lubrication levels for each mechanical component on the conveyor line to determine its transmission efficiency. This allows for the determination of the required servo motor speed to maintain the predetermined transmission efficiency for each component under varying lubrication levels. Adjusting the servo motor speed ensures the conveyor line maintains the predetermined transmission and production efficiency, enabling timely maintenance after the production cycle is completed, thus avoiding increased production costs due to power outages during maintenance.

[0156] 4. This servo motor-based speed control method addresses the issue of decreased transmission efficiency in the conveyor system. If the increased load caused by the item passing over the rollers leads to a further reduction in transmission efficiency, a corresponding load model is obtained. This involves simulating the movement and transmission of the item on the conveyor system to determine the load torque of the servo motor at different positions on the conveyor system. This allows for the determination of the required speed adjustment of the servo motor under different load torques to maintain the predetermined transmission efficiency of the conveyor system. Adjusting the servo motor speed ensures that the conveyor system maintains the predetermined transmission efficiency and production efficiency. This allows the equipment to complete its production cycle quickly and be repaired promptly, avoiding increased production costs due to power outages during maintenance. Attached Figure Description

[0157] Figure 1 This is a flowchart of the speed control method based on a servo motor according to the present invention;

[0158] Figure 2 This is a schematic diagram of the special and ordinary regions of the present invention. Detailed Implementation

[0159] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0160] Example 1: A speed control method based on a servo motor, see [link / reference] Figure 1 ,include:

[0161] Determine if the transmission efficiency is normal;

[0162] If the transmission efficiency is normal, the motor is controlled to maintain the initial speed and continuously acquire transmission efficiency.

[0163] If the transmission efficiency is abnormal, the transmission line will be divided into special areas and ordinary areas to determine the cause of the abnormal transmission efficiency.

[0164] Obtain the current load torque of the motor, denoted as . ;

[0165] in, ;

[0166] in, It is the output power. It is the rotational angular velocity;

[0167] Obtain the rated load torque of the motor, denoted as . ;

[0168] Obtain the theoretical load torque of the motor, denoted as . ;

[0169] in, ;

[0170] in, It is the coefficient of friction. It is load-bearing capacity. It is the radius of the mechanical part;

[0171] in, ;

[0172] Calculate the load torque variation in a specific region:

[0173] ;

[0174] like If so, the transmission efficiency in the special area is determined to be normal;

[0175] like If the transmission efficiency is abnormal in a specific area, the load model is obtained, and the adjustment speed is extracted. In other words, when an item passes through a special area, the frictional torque will increase. The rotation speed only needs to be dynamically adjusted when the item is in the special area, and the original initial speed can be restored when the item is in the normal area.

[0176] Calculate the load torque variation in the normal region:

[0177] ;

[0178] like If so, the transmission efficiency is determined to be normal within the normal range;

[0179] like If the transmission efficiency is abnormal within the normal range, a friction model is obtained, and the adjustment speed is extracted. In other words, the load torque should remain stable within the normal range. If the transmission efficiency is abnormal within the normal range, it indicates that there is a lack of lubrication or improper lubrication of mechanical parts in the transmission line, which increases the friction between mechanical parts and thus reduces the transmission efficiency. At this time, the whole system needs to be adjusted and a lubrication error warning should be given so that the staff can replenish or adjust the lubrication in time at the end of the production cycle and restore the mechanical parts to normal operation.

[0180] The control motor adjusts its speed from the initial speed to the adjusted speed and continuously obtains transmission efficiency.

[0181] Using the above method, when the transmission efficiency of the conveyor line decreases, it can be determined whether the decrease is due to insufficient or improper lubrication of mechanical parts causing increased friction between mechanical parts, or due to increased load caused by the items passing over the rollers. Based on the cause of the decrease in transmission efficiency, the speed of the servo motor can be adjusted accordingly to maintain the predetermined production efficiency, so that the equipment can complete the production cycle as soon as possible and be repaired in time, avoiding power outages during maintenance that would increase production costs.

[0182] Example 2 is an improvement on Example 1. This servo motor-based speed control method, in which the load model is obtained, includes determining the load torque in a normal region, specifically:

[0183] Obtain all the weights of the items and form a weight set;

[0184] Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ;

[0185] Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ;

[0186] Calculate the gravitational torque for the weight of each item in the weight set, denoted as . :

[0187] ;

[0188] in, It is the radius of the mechanical part;

[0189] Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ;

[0190] in, ;

[0191] in, It is the load quality. It is the radius of the timing belt pulley. It is the transmission ratio;

[0192] Obtain angular acceleration, denoted as ;

[0193] in, ;

[0194] in, It's the transmission speed. It is the radius of the roller;

[0195] Calculate the moment of inertia of each item in the weight set, denoted as . :

[0196] ;

[0197] Calculate the load torque in the general region for each item's weight in the weight set, denoted as . :

[0198] .

[0199] The acquisition of the load model includes determining the load torque in a specific region, specifically:

[0200] Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ;

[0201] Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ;

[0202] Calculate the gravitational torque for the weight of each item in the weight set, denoted as . :

[0203] ;

[0204] in, It is the radius of the mechanical part;

[0205] Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ;

[0206] in, ;

[0207] in, It is the load quality. It is the radius of the timing belt pulley. It is the transmission ratio;

[0208] Obtain angular acceleration, denoted as ;

[0209] in, ;

[0210] in, It's the transmission speed. It is the radius of the roller;

[0211] Calculate the moment of inertia of each item in the weight set, denoted as . :

[0212] ;

[0213] Calculate the material gravity component of the weight of each item in the weight set, denoted as . :

[0214] ;

[0215] in, It is the material filling rate. It is the density of the material. It is the cross-sectional area of ​​the circular tube conveyor belt. It is gravitational acceleration;

[0216] Calculate the conveyor belt forming force component for the weight of each item in the weight set, denoted as . :

[0217] ;

[0218] in, It is the bending moment generated by the stress in the conveyor belt cross section. It is the chord length corresponding to the bending moment;

[0219] Calculate the conveyor belt gravity component for the weight of each item in the weight set, denoted as . :

[0220] ;

[0221] in, It is the width of the conveyor belt. It is the spacing between the idler rollers. It refers to the thickness of the conveyor belt. It is the density of the conveyor belt. It is gravitational acceleration;

[0222] Calculate the roller contact torque for the weight of each item in the weight set, denoted as . :

[0223] ;

[0224] Calculate the load torque in the general region for each item's weight in the weight set, denoted as . :

[0225] .

[0226] This embodiment also provides that obtaining the load model includes determining the adjustment speed of the servo motor under different load torques, specifically:

[0227] Obtain the frictional torque for each item in the weight set, denoted as . The frictional torque inside the motor is obtained by a torque sensor;

[0228] Obtain the load torque for each item in the weight set, denoted as . ;

[0229] Calculate the output torque of the servo motor for each item's weight in the weight set, denoted as . :

[0230] ;

[0231] in, This refers to the rated torque of the servo motor.

[0232] Obtain all transmission speeds and form a speed set;

[0233] Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ;

[0234] Calculate the angular velocity of the servo motor when the conveyor line operates at the target conveyor speed, for each item in the weight set, and denote it as . :

[0235] ;

[0236] in, It is the radius of the mechanical part;

[0237] Calculate the transmission efficiency of the conveyor line for each item's weight in the weight set, denoted as . :

[0238] ;

[0239] in, It is the input voltage of the servo motor. It is the input current of the servo motor;

[0240] Calculate the torque required by the servo motor for each item weight in the weight set, denoted as . :

[0241] ;

[0242] Obtain the rated power of the servo motor, denoted as... ;

[0243] Calculate the required adjustment speed of the servo motor when the conveyor line transmits the items at different speeds for each item's weight in the weight set, denoted as . :

[0244] .

[0245] Example 3 is an improvement on Example 1. In this example, obtaining the friction model includes determining the coefficient of friction for each mechanical component under different levels of lubrication, specifically:

[0246] Acquire all mechanical components along the transmission line to form a component set;

[0247] Each mechanical component in the component set is identified as the target component;

[0248] Define the set of lubrication states of the target component, denoted as... The lubrication state set includes fluid lubrication, boundary lubrication, and mixed lubrication. Fluid lubrication involves a continuous lubricating film formed between the friction surfaces, completely separating the metal surfaces. It typically has a low coefficient of friction and is mainly used in medium- to high-speed surface contact friction pairs, such as sliding bearings. Boundary lubrication involves the friction surfaces being separated by a boundary film adsorbed onto the surfaces. The frictional properties depend on the adsorption properties of the boundary film and the surface, and it is mainly used in high-precision friction pairs under low-speed, heavy-load conditions. Mixed lubrication is a state where both fluid lubrication and boundary lubrication exist simultaneously, and it is mainly used during start-up, stopping, slow operation, and sudden changes in load or speed.

[0249] ;

[0250] in, , , These are fluid lubrication, boundary lubrication, and mixed lubrication;

[0251] All lubrication levels corresponding to each element in the simulated lubrication state set:

[0252] ;

[0253] in, It refers to the degree of lubrication. , This indicates that there is absolutely no lubrication. Indicates full lubrication;

[0254] Determining the coefficient of friction using a relational function. and The relationship between lubrication levels:

[0255] ;

[0256] in, It is the maximum coefficient of friction under unlubricated conditions. It is the coefficient of friction under moderate lubrication. It is a constant, representing the intensity of the effect of lubrication degree on the coefficient of friction;

[0257] Calculate the overall coefficient of friction of the transmission line for each mechanical component under different lubrication levels, denoted as . :

[0258] ;

[0259] in, It is the first The coefficient of friction of a mechanical component It is the first The input torque of each mechanical component It is the total number of mechanical parts in the transmission line, that is, the number of elements in the set of parts.

[0260] The acquisition of the friction model includes determining the transmission efficiency under different friction coefficients, that is, simulating the transmission efficiency of the transmission line under different lubrication levels for each mechanical component on the transmission line. Specifically:

[0261] An initial efficiency formula is defined, and the transmission efficiency calculated by this formula is the transmission efficiency without considering friction losses:

[0262] ;

[0263] in, It is the initial output torque. It is the initial input torque;

[0264] Obtain the overall coefficient of friction of the transmission line for each mechanical component in the component set under different lubrication levels. ;

[0265] Calculate the overall frictional torque, denoted as :

[0266] ;

[0267] in, It is the input torque;

[0268] Calculate the actual output torque, denoted as :

[0269] ;

[0270] It is a constant related to the mechanical structure, such as gear ratio, bearing friction coefficient, etc.

[0271] Calculate the transmission efficiency (considering frictional losses) of each mechanical component in the transmission line under different lubrication levels, denoted as . :

[0272] .

[0273] This embodiment also provides that obtaining the friction model includes determining the adjustment speed of the servo motor for each mechanical component in the transmission line under different lubrication levels, that is, determining the speed adjustment of the servo motor for each mechanical component in the transmission line under different lubrication levels to maintain a predetermined transmission efficiency, specifically:

[0274] Obtain all transmission speeds and form a speed set;

[0275] Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ;

[0276] To obtain the transmission efficiency loss of each mechanical component in the transmission line under different lubrication levels. ;

[0277] Calculate the motor's adjustment speed for each mechanical component in the transmission line under different lubrication levels, when the transmission line operates at different target speeds, and denote it as . :

[0278] .

[0279] Example 4 is an improvement upon Example 1. (See attached document for details.) Figure 2 In this embodiment, determining whether the transmission efficiency is normal specifically involves:

[0280] The current transmission efficiency of the transmission line is calculated using the efficiency formula, and denoted as . :

[0281] ;

[0282] In the efficiency formula, The current output power of the transmission line is as follows:

[0283] ;

[0284] in, This is the current transmission speed. It is the initial transmission efficiency. It is load-bearing capacity;

[0285] load capacity The specific formula is:

[0286] ;

[0287] in, It is the current load torque of the motor. It is the radius of the mechanical part;

[0288] In the efficiency formula, The current input power of the transmission line is as follows:

[0289] ;

[0290] in, It is the input torque of the servo motor. It is the angular velocity of the servo motor;

[0291] Input torque The specific formula is:

[0292] ;

[0293] in, It is the current load torque of the motor. It is frictional torque;

[0294] Among them, frictional torque The specific formula is:

[0295] ;

[0296] in, It is load-bearing capacity. It is the radius of the mechanical part. It is the coefficient of friction;

[0297] angular velocity The specific formula is:

[0298] ;

[0299] in, This is the current speed of the servo motor;

[0300] The difference in transmission efficiency is calculated and denoted as . :

[0301] ;

[0302] in, It is the initial transmission efficiency;

[0303] Set a threshold for transmission efficiency variation, denoted as . The threshold for the change in transmission efficiency is 5%;

[0304] like If so, the transmission efficiency is considered normal;

[0305] like If so, the transmission efficiency is determined to be abnormal.

[0306] This embodiment also provides that dividing the transmission line into special areas and ordinary areas specifically involves:

[0307] Obtain the direction in which the item is moving along the teleportation path and set it as the target direction;

[0308] Arbitrarily extract two adjacent idlers on the conveyor line and designate them as the front idler and the rear idler according to the target direction;

[0309] Extract the center points of the front idler roller and the rear idler roller respectively, and designate them as the front center point and the rear center point;

[0310] Connect the front center point and the back center point to form an analysis line;

[0311] Extract the midpoint of the analysis line and set it as the analysis midpoint;

[0312] Replace the rear idler with the front idler, and extract its other adjacent idler, which is then identified as the rear idler.

[0313] The midpoint between the front and rear idlers is extracted again and identified as the second midpoint.

[0314] Collect all the locations of the item as it moves from the midpoint of the analysis to the second midpoint, forming a location set;

[0315] The idler roller between the midpoint of the analysis and the second midpoint is identified as the analysis idler roller;

[0316] Extract all elements in the location set that have contact surfaces with the item, conveyor belt, and analysis roller, forming a contact set;

[0317] Extract and analyze the element corresponding to the center point of the idler roller in the contact set, and define it as the center element;

[0318] Extract the two elements in the contact set that are farthest from the center element, and designate them as the front tangent point and the back tangent point according to the target direction;

[0319] Using the front tangent point and the back tangent point as origins, draw parallel lines to the axis of the analysis roller, and define them as the front tangent line and the back tangent line, respectively.

[0320] The area on the conveyor line between the front tangent and the rear tangent of the analysis roller is defined as a special area;

[0321] The area on the conveyor line between the rear tangent of the front idler roller and the front tangent of the rear idler roller is defined as the normal area.

[0322] In this embodiment, when the transmission efficiency of the conveyor line decreases, it is determined whether the decrease in transmission efficiency is due to insufficient or improper lubrication of mechanical parts causing increased friction between mechanical parts, or due to increased load caused by the items passing through the rollers. Based on the cause of the decrease in transmission efficiency, the speed of the servo motor is adjusted accordingly to maintain the predetermined production efficiency, so that the equipment can complete the production cycle as soon as possible and perform maintenance in a timely manner, avoiding power outages during maintenance that would increase production costs.

Claims

1. A speed control method based on a servo motor, characterized in that: include: Determine if the transmission efficiency is normal; If the transmission efficiency is normal, the motor is controlled to maintain the initial speed and continuously acquire transmission efficiency. If the transmission efficiency is abnormal, the transmission line will be divided into special areas and ordinary areas. Obtain the current load torque of the motor, denoted as . ; Obtain the rated load torque of the motor, denoted as . ; Obtain the theoretical load torque of the motor, denoted as . ; Calculate the load torque variation in a specific region: ； like If so, the transmission efficiency in the special area is determined to be normal; like If the transmission efficiency is abnormal in a specific area, the load model is obtained, and the adjustment speed is extracted. ; Calculate the load torque variation in the normal region: ； like If so, the transmission efficiency is determined to be normal within the normal range; like If the transmission efficiency is abnormal within the normal range, a friction model is obtained, and the adjustment speed is extracted. ; The control motor adjusts its speed from the initial speed to the adjusted speed and continuously obtains transmission efficiency.

2. The speed control method based on a servo motor according to claim 1, characterized in that: The determination of whether the transmission efficiency is normal is specifically as follows: The current transmission efficiency of the transmission line is calculated using the efficiency formula, and denoted as . : ； In the efficiency formula, The current output power of the transmission line is as follows: ； in, This is the current transmission speed. It is the initial transmission efficiency. It is load-bearing capacity; load capacity The specific formula is: ； in, It is the current load torque of the motor. It is the radius of the mechanical part; In the efficiency formula, The current input power of the transmission line is as follows: ； in, It is the input torque of the servo motor. It is the angular velocity of the servo motor; Input torque The specific formula is: ； in, It is the current load torque of the motor. It is frictional torque; Among them, frictional torque The specific formula is: ； in, It is load-bearing capacity. It is the radius of the mechanical part. It is the coefficient of friction; angular velocity The specific formula is: ； in, This is the current speed of the servo motor; The difference in transmission efficiency is calculated and denoted as . : ； in, It is the initial transmission efficiency; Set a threshold for transmission efficiency variation, denoted as . ; like If so, the transmission efficiency is considered normal; like If so, the transmission efficiency is determined to be abnormal.

3. The speed control method based on a servo motor according to claim 1, characterized in that: The acquisition of the load model includes determining the load torque in the normal region, specifically: Obtain all the weights of the items and form a weight set; Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ; Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ; Calculate the gravitational torque for the weight of each item in the weight set, denoted as . : ； in, It is the radius of the mechanical part; Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ; Obtain angular acceleration, denoted as ; Calculate the moment of inertia of each item in the weight set, denoted as . : ； Calculate the load torque in the general region for each item's weight in the weight set, denoted as . : 。 4. The speed control method based on a servo motor according to claim 3, characterized in that: The acquisition of the load model includes determining the load torque in specific regions, specifically: Obtain the coefficient of friction of the transmission line for each item in the weight set, denoted as . ; Obtain the normal force of the transmission line for each item's weight in the weight set, denoted as . ; Calculate the gravitational torque for the weight of each item in the weight set, denoted as . : ； in, It is the radius of the mechanical part; Obtain the load inertia of the transmission line for each item's weight in the weight set, denoted as . ; Obtain angular acceleration, denoted as ; Calculate the moment of inertia of each item in the weight set, denoted as . : ； Calculate the material gravity component of the weight of each item in the weight set, denoted as . : ； in, It is the material filling rate. It is the density of the material. It is the cross-sectional area of ​​the circular tube conveyor belt. It is gravitational acceleration; Calculate the conveyor belt forming force component for the weight of each item in the weight set, denoted as . : ； in, It is the bending moment generated by the stress in the conveyor belt cross section. It is the chord length corresponding to the bending moment; Calculate the conveyor belt gravity component for the weight of each item in the weight set, denoted as . : ； in, It is the width of the conveyor belt. It is the spacing between the idler rollers. It refers to the thickness of the conveyor belt. It is the density of the conveyor belt. It is gravitational acceleration; Calculate the roller contact torque for the weight of each item in the weight set, denoted as . : ； Calculate the load torque in the general region for each item's weight in the weight set, denoted as . : 。 5. The speed control method based on a servo motor according to claim 4, characterized in that: The acquisition of the load model includes determining the adjustment speed of the servo motor under different load torques, specifically: Obtain the frictional torque for each item in the weight set, denoted as . ; Obtain the load torque for each item in the weight set, denoted as . ; Calculate the output torque of the servo motor for each item's weight in the weight set, denoted as . : ； in, This refers to the rated torque of the servo motor. Obtain all transmission speeds and form a speed set; Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ; Calculate the angular velocity of the servo motor when the conveyor line operates at the target conveyor speed, for each item in the weight set, and denote it as . : ； in, It is the radius of the mechanical part; Calculate the transmission efficiency of the conveyor line for each item's weight in the weight set, denoted as . : ； in, It is the input voltage of the servo motor. It is the input current of the servo motor; Calculate the torque required by the servo motor for each item weight in the weight set, denoted as . : ； Obtain the rated power of the servo motor, denoted as... ; Calculate the required adjustment speed of the servo motor when the conveyor line transmits the items at different speeds for each item's weight in the weight set, denoted as . : 。 6. The speed control method based on a servo motor according to claim 1, characterized in that: The acquisition of the friction model includes determining the coefficient of friction for each mechanical component under different levels of lubrication, specifically: Acquire all mechanical components along the transmission line to form a component set; Each mechanical component in the component set is identified as the target component; Define the set of lubrication states of the target component, denoted as... : ； in, , , These are fluid lubrication, boundary lubrication, and mixed lubrication; All lubrication levels corresponding to each element in the simulated lubrication state set: ； Determining the coefficient of friction using a relational function. With the degree of lubrication The relationship between them: ； in, It is the maximum coefficient of friction under unlubricated conditions. It is the coefficient of friction under moderate lubrication. It is a constant, representing the intensity of the effect of lubrication degree on the coefficient of friction; Calculate the overall coefficient of friction of the transmission line for each mechanical component under different lubrication levels, denoted as . : ； in, It is the first The coefficient of friction of a mechanical component It is the first The input torque of each mechanical component It represents the total number of mechanical parts in the transmission line.

7. The speed control method based on a servo motor according to claim 6, characterized in that: The acquisition of the friction model includes determining the transmission efficiency under different friction coefficients, specifically: Let an initial efficiency formula be defined: ； in, It is the initial output torque. It is the initial input torque; Obtain the overall coefficient of friction of the transmission line for each mechanical component in the component set under different lubrication levels. ; Calculate the overall frictional torque, denoted as : ； in, It is the input torque; Calculate the actual output torque, denoted as : ； It is a constant related to the mechanical structure; Calculate the transmission efficiency (considering frictional losses) of each mechanical component in the transmission line under different lubrication levels, denoted as . : 。 8. The speed control method based on a servo motor according to claim 7, characterized in that: The acquisition of the friction model includes determining the adjustment speed of the servo motor for each mechanical component in the transmission line under different lubrication levels, specifically: Obtain all transmission speeds and form a speed set; Each transmission speed in the speed set is sequentially identified as the target transmission speed, denoted as . ; To obtain the transmission efficiency loss of each mechanical component in the transmission line under different lubrication levels. ; Calculate the motor's adjustment speed for each mechanical component in the transmission line under different lubrication levels, when the transmission line operates at different target speeds, and denote it as . : ； in, It is the radius of the mechanical part.

9. The speed control method based on a servo motor according to claim 1, characterized in that: The division of the transmission line into special areas and ordinary areas is as follows: Obtain the direction in which the item is moving along the teleportation path and set it as the target direction; Arbitrarily extract two adjacent idlers on the conveyor line and designate them as the front idler and the rear idler according to the target direction; Extract the center points of the front idler roller and the rear idler roller respectively, and designate them as the front center point and the rear center point; Connect the front center point and the back center point to form an analysis line; Extract the midpoint of the analysis line and set it as the analysis midpoint; Replace the rear idler with the front idler, and extract its other adjacent idler, which is then identified as the rear idler. The midpoint between the front and rear idlers is extracted again and identified as the second midpoint. Collect all the locations of the item as it moves from the midpoint of the analysis to the second midpoint, forming a location set; The idler roller between the midpoint of the analysis and the second midpoint is identified as the analysis idler roller; Extract all elements in the location set that have contact surfaces with the item, conveyor belt, and analysis roller, forming a contact set; Extract and analyze the element corresponding to the center point of the idler roller in the contact set, and define it as the center element; Extract the two elements in the contact set that are farthest from the center element, and designate them as the front tangent point and the back tangent point according to the target direction; Using the front tangent point and the back tangent point as origins, draw parallel lines to the axis of the analysis roller, and define them as the front tangent line and the back tangent line, respectively. The area on the conveyor line between the front tangent and the rear tangent of the analysis roller is defined as a special area; The area on the conveyor line between the rear tangent of the front idler roller and the front tangent of the rear idler roller is defined as the normal area.

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