1. Introduction The world's first laser was invented in 1960, and China developed its first laser in 1961. Over the past 40 years, laser technology and its applications have developed rapidly, combining with multiple disciplines to form numerous application technology fields. Laser engraving and laser cutting are currently the most widely used applications of lasers. Laser engraving applications include: advertising, signage, arts and crafts, toys, architectural decoration, and printing plate making, using materials such as plexiglass, marble, ceramic tiles, crystal, jade, bamboo slips, wood products, plastics, paper, and non-metallic materials like plastic sheets. Laser cutting applications include: the automotive industry, computer and electrical housings, wood die-cutting, cutting of various metal parts and special materials, circular saw blades, acrylic, spring washers, copper plates for electronic components under 2mm thick, some metal mesh plates, steel pipes, tin-plated iron plates, zinc-plated steel plates, phosphor bronze, bakelite boards, thin aluminum alloys, quartz glass, silicone rubber, alumina ceramic sheets under 1mm thick, and titanium alloys used in the aerospace industry, etc. Currently, there are many domestic manufacturers specializing in laser engraving and cutting equipment. Their competition has shifted from laser technology to the effective control of laser equipment and processing technology. The ability to effectively solve the following problems has become crucial to their success or failure in this competition: vibration caused by high-speed laser scanning and rapid advancement; scanning area and accuracy; synchronous and reciprocating laser scanning misalignment; high-speed and stability of equipment movement on arbitrary complex trajectories; variable-speed cutting process; synchronous changes in laser power; reliability and safety issues in the processing process, etc. 2. Introduction to MPC6515 The MPC6515 controller is an offline control card specifically developed for laser engraving and cutting machine control systems. This control card can operate completely independently of a computer. The computer completes graphic editing, parameter setting, and path optimization, and generates processing data files. These processing data files can be copied to a USB flash drive and downloaded to the controller via the USB interface on the MPC6515. Processing operations can then be performed through the control panel PAD03. The controller's composition is shown in Figure 1. [IMG=Controller Composition Diagram]/uploadpic/THESIS/2007/11/2007111617134924068X.jpg[/IMG] Figure 1 Controller Composition Diagram The main functions of MPC6515 include: (1) Master USB technology, true offline operation and convenient controller upgrade; (2) Slave USB technology, computer data download up to 0.5M/s; (3) Industrial standard MODBUS communication protocol, convenient connection with HMI devices; (4) High-speed engraving position mapping, realizing high-speed and high-precision planar engraving; (5) Micro-segment cross-segment acceleration and deceleration control technology, realizing high-speed and stable cutting process; (6) Flexible laser power control mode, PWM control or analog quantity control. 3. High-Speed ​​Scanning and Engraving Solution To meet the demands of high-speed engraving, the MPC6515, based on its dedicated RAM area, employs bit-based pixel control. This not only solves the processing of large-format graphics but also achieves simultaneous scanning by combining motion commands and laser on/off commands, improving scanning accuracy and ensuring engraving quality. Its control principle is as follows: To store large amounts of scan data and achieve synchronous scanning, the MPC6515 cleverly utilizes the FPGA's built-in 2MBit block RAM resources to store the image data for each line. The MPC6515 controller uses its internal 9 address lines to address the 32-bit data bus interface RAM area, i.e., 16KBit. If each scan pixel is 0.1mm, theoretically, the scanning area can reach 1.6m at the highest scanning accuracy. Scanning proceeds sequentially from low-order address to high-order address, and from low-order to high-order bits within each line. With each scan pulse, the stepper motor drives the laser head forward one step, simultaneously reading one piece of graphic data from the RAM area, and determining whether to switch the laser on or off based on the '1' or '0' state of the read data. Because the DSP writes one line of 512×32-bit graphic data to the FPGA's RAM area each time, the DSP does not need to write data to the FPGA during the processing of these 16K-bit data. This not only greatly improves the working efficiency of the laser equipment but also ensures the synchronization of scanning. It also provides feasibility for reverse compensation in software for overall misalignment that occurs during reciprocating scanning. During synchronous scanning, to improve scanning accuracy and image quality, the MPC6515 internally provides an 8-bit laser control register (LCR). By setting the LCR value (0~255), the scanning accuracy can be improved. 4. High-Speed ​​Cutting Solution In the laser cutting process, to improve efficiency, it is necessary to increase the cutting speed, i.e., the vector velocity of the laser head moving along the curve. Since the curves constituting arbitrary shapes are not necessarily smooth, i.e., there may be mathematical inflection points, and if the laser head moves along the shape trajectory at a constant vector velocity, mechanical impact may occur at the inflection point as the speed increases. This is because the direction of the vector velocity changes at the inflection point, generating acceleration. If this acceleration exceeds the mechanically permissible value, it will cause mechanical impact. Therefore, if we want to increase the processing speed while avoiding impact, there are two solutions: (1) smooth transition at the inflection point; (2) decelerate at the inflection point, i.e., reduce the magnitude of the vector velocity. The first solution requires a lot of smooth transition processing for more complex shapes, which will reduce the overall efficiency. Therefore, the second solution is more feasible, but if the speed is reduced to a set value at each inflection point, the overall efficiency will also be reduced. Therefore, it is necessary to study an algorithm to calculate and handle the deceleration problem at each inflection point, so as to improve the overall processing efficiency while avoiding impact. From the perspective of improving the overall processing efficiency, the deceleration range at the inflection point cannot be too large, and the speed to be reduced is related to the shape of the inflection point. [IMG=Motion Trajectory Curve]/uploadpic/THESIS/2007/11/2007111617171015291D.jpg[/IMG] Figure 2 shows the motion trajectory curve, which is a magnified view of a section of the curve. Points B, C, and D will experience acceleration due to changes in the direction of the vector velocity. If the magnitude of the vector velocity remains constant throughout the motion, the acceleration values ​​at points B, C, and D, from largest to smallest, are: B>C>D. To ensure that the acceleration at the three points is less than or equal to the mechanically permissible acceleration, the magnitude of the vector velocity at these three points needs to be reduced to a suitable value. Obviously, the magnitudes of the vector velocities at these three points should not be equal. Therefore, it is necessary to establish a mathematical relationship between the magnitude of the vector velocity and the acceleration at the inflection point: [IMG=Velocity Vector]/uploadpic/THESIS/2007/11/2007111617193739055W.jpg[/IMG] Figure 3 shows the velocity vector. Points P1, P2, and P3 define two adjacent line segments. Based on the absolute coordinates of these three points, the unit vectors of the two line segments can be calculated. Let the magnitude of the vector velocity at point P2 be vP2. After a time interval Δt, the direction of the vector velocity changes from v to v, resulting in the following acceleration: [align=center][/align] Let be the turning acceleration parameter, then the relationship between the velocity value at the turning point and the acceleration and geometric quantities can be obtained: Based on the above principles, at a given time, the velocities at n-1 connection points of any curve composed of n micro-segments can be calculated. Considering that the speed cannot exceed the set processing speed during the entire curve processing process, if the calculated speed at the connection point exceeds the set processing speed, it is considered that no speed reduction is needed at that point. Based on the set vector acceleration, processing speed, and calculated speed at the connection point, the speed curve shown in Figure 4 can be obtained. 5. Summary The MPC6515 is a dedicated motion control card for laser engraving and cutting applications. It has been optimized for both hardware and software systems in laser engraving and cutting processes and has been selected by many laser equipment manufacturers both domestically and internationally. Proceedings of the 2nd Servo and Motion Control Forum Proceedings of the 3rd Servo and Motion Control Forum