This article introduces Baumueller's servo drive system, demonstrating how high-speed, high-precision, fixed-length shearing of steel plates is achieved through functional modules developed for flying shear applications. The article describes the key technologies of Baumueller's flying shear control. 1. Flying Shear Application Introduction Flying shears are used in the steel processing industry to drive the shearing blade during steel plate feeding to achieve fixed-length shearing of steel. Because the flying shear motion does not require stopping the feeding process and the cutting length and feeding speed can be freely modified during processing, the processing efficiency of steel plate shearing is greatly improved. Baumueller offers a full range of high-power synchronous/asynchronous servo motors and high-performance Baumueller maXX series servo drives. The Baumueller maXX series servo drives are controlled by a drive-level PLC, which quickly synchronizes and accesses data with the servo drive via a backplane bus and supports the IEC 61131-3 multi-tasking real-time operating system. Baumueller has developed a series of function blocks specifically for flying shear, rotary shearing, and tracking shearing applications to facilitate the implementation of these three types of applications. 2 System Structure [IMG=Figure 1 Baumürer Flying Shear Application System Mechanism]/uploadpic/THESIS/2007/11/200711161314027219404.jpg[/IMG] Figure 1 Baumürer Flying Shear Application System Mechanism [IMG=Figure 2 Rotary Cutting Motion Curve]/uploadpic/THESIS/2007/11/20071116131539494473.jpg[/IMG] Figure 2 Rotary Cutting Motion Curve Figure 1 shows the system structure of the Baumürer flying shear application. Its feeding unit is controlled by a feeding drive system, responsible for smooth, slip-free feeding; the cutting unit is controlled by a cutting servo system, which drives the shear blade to perform fixed-length cutting of the steel plate according to the set cutting length and feeding speed. Servo system control parameters such as cutting length and feeding speed are input through the human-machine interface; the material speed and position are fed back to the cutting drive system by an encoder. The encoder signal source is divided into passive and active types: (1) Passive type: The encoder installed on the measuring wheel feeds back the material speed and position; The advantage is that the measuring wheel is driven to rotate by the material, and the detected value is the actual speed and position of the material; The disadvantage is that the signal fluctuation is large. (2) Active type: The encoder of the feeding motor feeds back the material speed and position; The advantage is that the signal is stable and the fluctuation is small; The disadvantage is that when the material slips between the material and the feeding wheel, the feedback signal of the feeding motor encoder cannot accurately reflect the actual speed and position of the material. 3 Baumiller rotary cutter and flying shear module The main functional blocks of Baumiller for flying shear are as follows: TM_SyncRot_Init: Initialize the rotary cutter/flying shear function according to the control requirements; TM_SyncCam_Init: Set the curve of the synchronization zone; TM_MasterEncoder: Calculate the speed and position of the material according to the encoder feedback value; TM_SyncRot: Generate the current axis position setting value and speed setting value according to the material speed and position; TM_DriveEncoder: Control the movement of the current axis according to the speed setting value. In addition, based on controlling the flying shear motion of the cutting blade, Baumüller can also achieve some special process requirements, such as a fixed ratio between the cutting speed and the feeding speed in the synchronization zone; setting acceleration and deceleration switching points; and color mark cutting, etc. [IMG=Figure 3 Synchronization Zone Motion Model]/uploadpic/THESIS/2007/11/2007111613195216220M.jpg[/IMG] Figure 3 Synchronization Zone Motion Model [IMG=Figure 4 Synchronization Zone Motion Curve]/uploadpic/THESIS/2007/11/2007111613232639336E.jpg[/IMG] Figure 4 Synchronization Zone Motion Curve 4 Motion Mode The cutting unit adopts an eccentric shaft transmission and a mechanical synchronous positioning shaft to ensure that the upper and lower blade holders are oriented, move at the same speed, and are positioned, so that the fixed blade holder of the cutting blade rotates. The area where the cutting speed and the feeding speed are synchronized is called the synchronization zone. The area where the upper and lower blades mesh within the synchronization zone is the shearing zone. The area outside the synchronization zone is called the compensation zone. In the application of the Baumür flying shear, the shearing blade's motion trajectory is divided into the synchronization zone and the compensation zone, and its motion mode is also divided into synchronous motion and compensation motion. Synchronous motion is when the shearing motor synchronizes with the material speed and position in the synchronization zone. During this time, the upper and lower blades mesh to complete the shearing process of the steel plate. After leaving the synchronization zone, depending on the cutting length, the shearing blade needs to accelerate or decelerate to compensate for different cutting lengths, which is called compensation motion. Depending on the cutting length, there are three different compensation motion modes: (1) When cutting long materials, if the cutting length is greater than twice the blade circumference, the blade decelerates and stops at the set point after the cutting action is completed in the shearing cycle, and then accelerates into the synchronization zone. (2) When cutting medium materials, if the cutting length is greater than the blade circumference but less than twice the blade circumference, the blade decelerates but does not stop at the set point after the cutting action is completed, and then accelerates to enter the next cutting. (3) When the cutting length of short material is less than the circumference of the blade, the cutting action is accelerated to the set point immediately after completion, and then decelerated to enter the next cutting. 5 Application in flying shear project When no additional curve is set for the synchronization zone, the default motion mode of the shear blade is rotary cutting. When the shear blade moves synchronously, the rotation speed of the shear blade and the feeding speed are the same. The actual measured curve during medium material cutting is shown in Figure 2. However, for steel plate shearing, if the rotation speed of the shear blade and the feeding speed are the same during synchronous movement, the component of the shear blade in the feeding direction will not be consistent with the feeding speed during shearing, which will cause the steel plate to be blocked or dragged. Therefore, when cutting steel plates, the component of the shear blade speed in the feeding direction and the feeding speed need to be consistent in the synchronization zone. At this time, a curve needs to be added to the synchronization zone to achieve the above function. The mathematical model of the synchronous zone motion is shown in Figure 3, where r = 60mm (r is the radius of the eccentric shaft), = 80° (0°～80° is the synchronization zone), = 60° (10°～70° is the shearing area), and the area outside the synchronization zone is the compensation zone. The synchronization zone is larger than the shearing zone because a certain distance is needed to smooth out speed changes; otherwise, it would cause a large mechanical impact. Length of material movement during synchronization: (1.1) Length of material movement during shearing: (1.2) Setting the position of the material entering the synchronization zone as the origin, then: Shearing start position: (1.3) Shearing end position: (1.4) The following relationship can be obtained: (8.567≤x≤68.567) (1.5) Where α(x)-angle of the shear blade in the synchronization zone; x-position of the material in the synchronization zone; r-radius of the shear blade; [IMG=Fig.5 Flying Shear Motion Curve]/uploadpic/THESIS/2007/11/2007111613524031315T.jpg[/IMG] Fig.5 Speed ​​relationship of flying shear motion curve: In order to make the shear blade achieve smooth acceleration and deceleration motion, a transition curve is added to 0°～10° and 70°～80° in the synchronization zone to make the speed transition smooth and reduce mechanical impact. The speed curve of the shear blade in the synchronization zone after adding the transition curve is shown in Fig.4. After adding the synchronization zone curve, the complete shearing blade speed curve during medium-weight material shearing is shown in Figure 5. This motion curve fully meets the motion control requirements of the flying shear, with low mechanical impact and high control accuracy. 5. Conclusion After six months of testing and operation, the machine tool operates normally and stably, producing a smooth shear cut. It achieves good accuracy at different shearing lengths and high-speed feeding, significantly improving customer production efficiency. (Proceedings of the 2nd Servo and Motion Control Forum; Proceedings of the 3rd Servo and Motion Control Forum)