A multi-degree-of-freedom manipulator teaching aid based on PLC

Abstract

The utility model discloses a kind of multi-degree-of-freedom manipulator teaching aid based on PLC, it is related to teaching equipment technical field, the device includes platform, sliding base connected with the platform X direction sliding, gantry support fixed in sliding base, guide rail along the Z direction sliding of gantry support and manipulator along the Y direction sliding of guide rail;X direction drive mechanism moves sliding base by X direction screw rod drive, Y direction drive mechanism moves manipulator by Y direction screw rod drive, Z direction drive mechanism adopts synchronous belt connection Z direction drive motor and two Z direction screw rods, ensure guide rail both ends slider synchronous lifting;PLC controller is integrated in platform, for controlling each drive motor and manipulator action.This teaching aid realizes accurate positioning and grasping operation of manipulator in three-dimensional space by modular design, compact structure and intuitive operation, suitable for the practice training of PLC programming and manipulator collaborative control in industrial automation teaching.

Description

Technical Field

[0001] This utility model relates to the field of teaching equipment technology, and in particular to a PLC-based multi-degree-of-freedom robotic arm teaching aid. Background Technology

[0002] In the field of industrial automation education, robotic arms are an important teaching tool for understanding PLC control principles, and their design must balance structural simplification and functional integrity. However, existing teaching robotic arm devices are mostly simplified improvements based on industrial robotic arms, and still have several limitations. First, the Z-axis lifting mechanism of traditional robotic arms often uses a single motor with a belt-driven double lead screw structure. However, due to the elastic properties of the belt material and the potential risk of slippage during transmission, it is difficult for the two lead screws to achieve strictly synchronous rotation. This asynchrony will cause the lifting speed of the sliders on both sides of the guide rail to deviate, which in turn will cause the guide rail to tilt or jam, affecting the positioning accuracy of the robotic arm in the vertical direction. After long-term use, the accumulation of transmission errors may exacerbate mechanical wear and reduce equipment stability. Second, although the complex structure of industrial robotic arms can meet production needs, their multi-axis linkage design actually increases the difficulty of understanding for students in teaching. For example, the layout of the drive mechanism (such as lead screws and guide rails) is usually hidden in a closed frame, and the motion transmission process lacks intuitive visibility. Students find it difficult to observe the coordination relationship between various components, weakening the teaching effect of the correlation between PLC programming and mechanical motion. Furthermore, the multi-degree-of-freedom motion control of existing teaching aids for robotic arms often relies on distributed drive units, resulting in bulky and expensive equipment that limits its widespread adoption in teaching scenarios. For example, to achieve multi-axis rotation at the end effector of a robotic arm, traditional solutions require stacking multiple independent servo motors or rotating mechanisms, which not only occupies space but also increases the complexity of electrical wiring, making troubleshooting and maintenance difficult. The underlying technical contradiction lies in the fundamental difference between the design goals of industrial robotic arms (high load, high precision) and the requirements of teaching scenarios (lightweight, transparent, low cost). Directly simplifying the structure of industrial robotic arms may sacrifice the reliability of key motion functions; while completely redesigning teaching devices requires balancing structural complexity and functional implementation costs. For example, in the dual-screw synchronous drive scheme, while using a rigid coupling can avoid belt drive errors, it significantly increases machining costs and requires extremely high installation precision, making it difficult to adapt to the frequent disassembly and assembly environment of teaching equipment. Therefore, how to construct a compact, cost-effective, and easily observable robotic arm teaching aid while ensuring multi-degree-of-freedom motion precision has become a pressing technical challenge in this field. Utility Model Content

[0003] Existing robotic arm teaching aids, due to their simplified structure based on industrial robotic arms, suffer from problems such as large size, poor transmission synchronization, and Z-axis lifting mechanisms prone to guide rail tilting due to belt slippage, affecting positioning accuracy. Furthermore, the dispersed layout of multi-axis drive units results in complex structures, hindering teaching observation and cost control. This invention provides a PLC-based multi-degree-of-freedom robotic arm teaching aid.

[0004] To achieve the above-mentioned utility model objectives, this utility model provides a PLC-based multi-degree-of-freedom robotic arm teaching aid, comprising:

[0005] platform;

[0006] A slide block is slidably connected to the platform in the X direction, and the bottom of the slide block is provided with a protrusion that mates with the platform's X-direction sliding groove;

[0007] The gantry support, which is set on the upper side of the slide, includes two columns and a crossbeam. The columns are fixed to both sides of the slide along the Y direction, and the crossbeam is horizontally connected to the upper ends of the two columns.

[0008] The guide rail is slidably mounted between two columns along the Z-axis, and the side wall of the guide rail is provided with a Y-axis side groove for the robot arm to slide.

[0009] The robotic arm is slidably connected to the Y-axis side groove of the guide rail;

[0010] The X-axis drive mechanism is mounted on the platform and includes an X-axis drive motor and an X-axis lead screw, which is threadedly connected to the slide.

[0011] The Y-axis drive mechanism is mounted on the guide rail and includes a Y-axis drive motor and a Y-axis lead screw, which is threadedly connected to the robot arm.

[0012] The Z-axis drive mechanism, mounted on the gantry bracket, includes:

[0013] The Z-axis drive motor is fixed to the crossbeam;

[0014] Two Z-axis lead screws are rotatably and vertically mounted on the inner side of two columns via bearings, and a synchronous pulley is fixed at the top of each Z-axis lead screw;

[0015] The synchronous belt is meshed between the synchronous pulley on the output shaft of the Z-axis drive motor and the synchronous pulleys on the two Z-axis lead screws;

[0016] The slider consists of two blocks, which are slidably connected to the column on the same side along the Z direction and threadedly connected to the corresponding Z-direction lead screw.

[0017] Both ends of the guide rail are fixedly connected to the slider on the same side;

[0018] The PLC controller is fixed on the platform and electrically connected to the robot arm, X-axis drive motor, Y-axis drive motor, and Z-axis drive motor.

[0019] Traditional belt drives suffer from insufficient synchronization of the Z-axis double lead screws due to elastic deformation and slippage, failing to meet the requirements for smooth lifting of the guide rail. Long-term use also leads to accumulated errors and increased mechanical wear. Preferably, the PLC-based multi-degree-of-freedom manipulator teaching aid of this invention uses a toothed synchronous belt and toothed pulleys that match the toothed synchronous belt. The synchronous belt also includes a tension adjustment device, comprising an adjustable idler pulley or tensioning pulley.

[0020] If the X-axis lead screw is not fixed to the bearing seats at both ends, it is prone to bending deformation due to the cantilever structure, resulting in a decrease in the sliding accuracy and affecting the accuracy of three-dimensional coordinate positioning. Preferably, in the PLC-based multi-degree-of-freedom manipulator teaching aid of this utility model, the two ends of the X-axis lead screw are fixed to the X-axis ends of the platform through bearing seats and mate with the threaded holes at the bottom of the slide; the X-axis drive motor is electrically connected to the PLC controller and is used to drive the slide to move along the X-axis of the platform.

[0021] When the Y-axis lead screw is not fixed to both ends of the guide rail, the sliding of the robot arm is easily affected by the vibration of the lead screw, resulting in Y-axis positioning deviation and reducing the reliability of the grasping operation. This utility model presents a PLC-based multi-degree-of-freedom robot arm teaching aid. The two ends of the Y-axis lead screw are fixed to the Y-axis ends of the guide rail via bearing seats, and mate with the threaded holes of the robot arm. The Y-axis drive motor is electrically connected to the PLC controller to drive the robot arm to move along the Y-axis of the guide rail.

[0022] The lack of multi-degree-of-freedom motion capabilities at the end effector of robotic arms makes it difficult to demonstrate rotational and swinging movements, thus limiting students' understanding of complex motion logic controlled by PLCs. Preferably, this utility model provides a PLC-based multi-degree-of-freedom robotic arm teaching aid, in which the robotic arm is connected to a Y-axis lead screw via a swing mechanism, the swing mechanism comprising:

[0023] The electric rotary seat has a fixed end that is threadedly connected to a Y-axis lead screw, and a rotating end that is fixedly connected to a robot arm.

[0024] A rotating shaft passes through a U-shaped opening at the rotating end of the electric rotary seat and is fixed to the robotic arm;

[0025] The first servo motor is fixed to the outside of the electric rotary base, and its output end is coaxially connected to the rotating shaft to drive the robot arm to rotate around the rotating shaft.

[0026] The second servo motor is fixed to the rotating shaft, and its output end is fixed to the robot arm. It is used to drive the robot arm to swing around an axis perpendicular to the rotating shaft.

[0027] Dispersed servo control units lead to complex electrical wiring, increasing the failure rate, and multi-axis collaborative control is difficult, hindering the intuitiveness of teaching demonstrations. Preferably, the PLC-based multi-degree-of-freedom manipulator teaching aid of this invention has an electric rotary base, a first servo motor, and a second servo motor all electrically connected to the PLC controller to achieve multi-degree-of-freedom motion control of the manipulator.

[0028] The lack of an integrated user interface in existing PLC controllers makes it difficult for students to input commands in real time and observe the robot's motion feedback, thus affecting the effectiveness of practical teaching. Preferably, this utility model provides a PLC-based multi-degree-of-freedom robot teaching aid, where the PLC controller has a programming interface and an operation panel for inputting coordinate commands and controlling the robot's positioning and grasping operations in three-dimensional space.

[0029] This utility model has at least the following beneficial effects:

[0030] 1. This utility model eliminates the elastic slippage problem of traditional belt drives by using a synchronous belt to drive a double Z-axis lead screw, ensuring that the sliders at both ends of the guide rail rise and fall synchronously and avoiding guide rail tilting; the modular layout integrates the X / Y / Z-axis drive mechanism and PLC controller, reducing the size and complexity of the equipment and improving the intuitiveness of teaching demonstrations.

[0031] 2. The meshing design of the toothed synchronous belt and pulley in this utility model, combined with the tension adjustment device, enhances transmission rigidity, reduces the risk of slippage, and extends the service life of the equipment; the adjustable tension of the synchronous belt adapts to the stability requirements under different load conditions.

[0032] 3. The X-axis lead screw of this utility model is fixed by bearing seats at both ends, which avoids the deflection of the lead screw caused by the cantilever structure, ensures the linear accuracy of the slide block moving along the X-axis of the platform, and improves the reliability of three-dimensional positioning.

[0033] 4. The Y-axis lead screw of this utility model is fixed at both ends of the guide rail, which reduces the impact of lead screw vibration on the Y-axis movement of the robot, ensures the accuracy of the gripping action, and simplifies the support structure of the guide rail.

[0034] 5. The swing mechanism of this utility model realizes the rotation and swing freedom of the robot arm through the coordinated control of the electric rotating base and the dual servo motors, intuitively demonstrating the multi-axis motion logic and enhancing students' understanding of the correlation between PLC programming and mechanical motion.

[0035] 6. The integrated electrical control of this utility model connects the electric rotary base and the servo motor to the PLC controller, reducing wiring complexity, lowering the failure rate, and facilitating debugging and maintenance during the teaching process.

[0036] 7. The programming interface and operation panel of the PLC controller of this utility model allow students to directly input coordinate commands and observe the real-time response of the robot, which enhances the teaching effect of combining theory and practice and improves the ease of operation.

[0037] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0038] Figure 1 This is a main view of a PLC-based multi-degree-of-freedom robotic arm teaching aid according to one of the technical solutions of this utility model;

[0039] Figure 2 This is a left view of a PLC-based multi-degree-of-freedom robotic arm teaching aid in one of the technical solutions of this utility model;

[0040] Figure 3 This is a top view of a PLC-based multi-degree-of-freedom robotic arm teaching aid according to one of the technical solutions of this utility model;

[0041] Figure 4 This is a three-dimensional structural diagram of a pendulum mechanism in one of the technical solutions of this utility model.

[0042] In the diagram, 1 is the platform; 11 is the slide rail; 2 is the slide block; 3 is the gantry support; 31 is the column; 32 is the crossbeam; 4 is the guide rail; 41 is the side groove; 5 is the robot arm; 6 is the PLC controller; 71 is the X-axis drive motor; 72 is the X-axis lead screw; 81 is the Y-axis drive motor; 82 is the Y-axis lead screw; 91 is the Z-axis drive motor; 92 is the Z-axis lead screw; 93 is the slider; 94 is the synchronous belt; 95 is the tension adjustment device; 1001 is the electric rotary seat; 1002 is the rotating shaft; 1003 is the first servo motor; and 1004 is the second servo motor. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the embodiments, so that those skilled in the art can implement it based on the description.

[0044] It should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Example

[0045] like Figures 1-4 As shown, this utility model provides a PLC-based multi-degree-of-freedom robotic arm teaching aid, comprising:

[0046] Platform 1;

[0047] The slide 2 is slidably connected to the platform 1 in the X direction. Two slide grooves 11 are provided on the platform 1 along the X direction. The bottom of the slide 2 is provided with a protrusion that cooperates with the X-direction slide grooves 11 of the platform 1.

[0048] The gantry support 3 is located on the upper side of the slide block 2 and includes two columns 31 and a crossbeam 32. The columns 31 are respectively located on both sides of the slide block 2 along the Y direction, and the crossbeam 32 is horizontally connected to the upper end of the two columns 31.

[0049] The guide rail 4 is slidably disposed between the two columns 31 of the gantry bracket 3 along the Z direction; the side wall of the guide rail 4 is provided with a Y-direction side groove 41 for the robot arm 5 to slide.

[0050] The robotic arm 5 is slidably connected to the guide rail 4 along the Y direction;

[0051] The X-axis drive mechanism is mounted on the platform 1 and includes an X-axis drive motor 71 and an X-axis lead screw 72. The X-axis lead screw 72 is threadedly connected to the slide 2.

[0052] The Y-axis drive mechanism is mounted on the guide rail 4 and includes a Y-axis drive motor 81 and a Y-axis lead screw 82. The Y-axis lead screw 82 is threadedly connected to the robot arm 5.

[0053] A Z-axis drive mechanism is disposed on the gantry bracket 3, and the Z-axis drive mechanism includes:

[0054] Z-axis drive motor 91 is mounted on the crossbeam 32;

[0055] Two Z-axis lead screws 92 are rotatably and vertically mounted on the inner side of two columns 31 via bearings, and a synchronous pulley is fixed at the top of each Z-axis lead screw 92;

[0056] Synchronous belt 94 is meshed between the synchronous pulley of the output shaft of Z-axis drive motor 91 and the synchronous pulleys of two Z-axis lead screws 92;

[0057] Two sliders 93 are provided, and they are respectively slidably connected to the column 31 on the same side along the Z direction. The sliders 93 are threadedly connected to the corresponding Z-direction lead screw 92.

[0058] The two ends of the guide rail 4 are fixedly connected to the slider 93 on the same side;

[0059] When the Z-axis drive motor 91 is working, it drives the two Z-axis lead screws 92 to rotate through the synchronous belt 94, and drives the slider 93 to drive the guide rail 4 to slide along the Z-axis of the column 31 to the designated position.

[0060] The PLC controller 6 is mounted on the platform 1 and is electrically connected to the robot arm 5, the X-axis drive motor 71, the Y-axis drive motor 81, and the Z-axis drive motor 91.

[0061] Specifically:

[0062] For basic structural modules

[0063] Platform 1 can be made of aluminum alloy profile with a thickness ranging from 10-15mm. Its surface has X-axis grooves 11, with a groove spacing of 20-30mm. The bottom of the slide block 2 has protrusions matching the grooves 11, with a height of 5-8mm and a width of 15-20mm. The column 31 of the gantry support 3 is made of welded square steel with a cross-sectional dimension of 40mm×40mm. The crossbeam 32 is fixed to the column 31 with bolts. The Y-axis side groove 41 of the guide rail 4 has a width of 8-12mm and a depth of 5-8mm. The end effector gripper of the robotic arm 5 can use an open-source model (such as a Robotiq 2F-85 compatible structure), with a gripping force range of 5-10N.

[0064] During assembly, platform 1 is horizontally installed on the teaching stand; slide 2 is embedded into the X-direction slide groove 11 of platform 1 through a protrusion;

[0065] The gantry support 3 is vertically welded to the upper surface of the slide block 2; the guide rail 4 is slidably connected to the column 31 of the gantry support 3 via the slider 93; the robot arm 5 is slidably connected to the guide rail 4 via the side groove 41. Working process: When the slide block 2 moves along the X direction of the platform 1, it drives the gantry support 3 to move as a whole; the guide rail 4 moves up and down along the Z direction of the gantry support 3; the robot arm 5 slides along the Y direction of the guide rail 4 to achieve three-dimensional spatial positioning.

[0066] For the drive mechanism module

[0067] The X-axis lead screw 72 can be a ball screw with a diameter of 8mm and a lead of 2mm. The length of the lead screw is determined according to the dimensions of platform 1 (e.g., 600-800mm). Both ends are fixed to the X-axis ends of platform 1 via flange bearing seats. The Y-axis lead screw 82 is a trapezoidal lead screw with a diameter of 6mm and a lead of 4mm. Its length matches the Y-axis travel of guide rail 4 (e.g., 300-400mm). The Z-axis lead screw 92 is a ball screw with a diameter of 10mm and a lead of 5mm. Each lead screw is 500-600mm long, and the top synchronous pulley has a module of 2 and 20 teeth. The synchronous belt 94 is a polyurethane toothed belt with a width of 6mm and a tooth pitch of 2mm. The tension adjustment device 95 can be installed on the crossbeam 32, and the position of the idler pulley is controlled by adjusting the screw.

[0068] During assembly, the X-axis lead screw 72 is parallel to the X-axis of platform 1, and the bearing seats at both ends are fixed with bolts; the Y-axis lead screw 82 is parallel to the Y-axis side groove 41 of guide rail 4, and the bearing seats at both ends are fixed to the two ends of guide rail 4; the Z-axis lead screw 92 is vertically installed inside the column 31, and the synchronous belt 94 meshes between the pulley of drive motor 91 and lead screw 92; the slider 93 engages with the Z-axis lead screw 92 through a threaded hole and is fixed to the two ends of guide rail 4 with screws. Working process: X-axis drive motor 71 drives slide 2 to move via lead screw 72; Y-axis drive motor 81 drives robot arm 5 to slide along guide rail 4 via lead screw 82, with a speed range of 10-50 mm / s; Z-axis drive motor 91 drives the double lead screws 92 to rotate synchronously via synchronous belt 94, causing guide rail 4 to rise and fall at a speed of 5-20 mm / s.

[0069] For the control module

[0070] The PLC controller 6 can be a Siemens S7-1200 series basic module, integrating digital input / output interfaces. The programming interface supports RS485 or Ethernet communication, and the operation panel uses a 7-inch touchscreen with a resolution of 800×480. Electrical connections use shielded cables with a wire diameter of 0.5mm², and signal lines are routed separately to avoid interference.

[0071] During assembly, the PLC controller 6 is installed in the control box on the side of the platform 1; the X-axis drive motor 71, the Y-axis drive motor 81, and the Z-axis drive motor 91 are connected to the I / O port of the PLC controller 6 via cables; the signal lines of the servo motors (first servo motor 1003 and second servo motor 1004) of the robot arm 5 are connected to the output terminal of the PLC controller 6.

[0072] In one example of the working process: the target coordinates (X, Y, Z) are input via the operation panel. After parsing the instructions, the PLC controller 6 controls the X / Y / Z axis drive motors to move sequentially, ultimately driving the robotic arm 5 to the designated position and perform the grasping action. During the movement, the position data of each axis is fed back to the PLC via encoders, realizing closed-loop control.

[0073] In this implementation, the aluminum alloy platform and modular design reduce overall weight, facilitating transport and teaching demonstrations. The side groove 41 of the robotic arm 5, in conjunction with linear bearings, ensures smooth sliding and positioning accuracy that meets teaching requirements. The rigid transmission scheme of the synchronous belt 94 and double Z-axis lead screws 92 eliminates the risk of slippage associated with traditional belts, and the synchronous lifting error of the guide rail 4 is less than 0.2mm. The lead and diameter of the X / Y-axis lead screws are optimized to balance speed and accuracy. The integrated PLC controller 6 simplifies the operation process; students can program directly via a touchscreen and observe the real-time correspondence between the robotic arm's movements and the PLC logic, enhancing the intuitiveness of teaching.

[0074] Furthermore, in another technical solution, such as Figure 2 As shown, the synchronous belt 94 is a toothed synchronous belt, and the synchronous pulley is a toothed pulley that matches the toothed synchronous belt; the synchronous belt 94 is also provided with a tension adjustment device 95, including a movable and adjustable idler pulley or tension pulley.

[0075] Specifically, the toothed synchronous belt 94 can be made of polyurethane material, with a bandwidth ranging from 5-8 mm, a tooth pitch of 2 mm or 3 mm, and a tooth profile of trapezoidal or arc shape. The synchronous pulley is made of aluminum alloy material that matches the tooth profile, with a module of 2 and 20-30 teeth. For example, a synchronous belt 94 with a bandwidth of 6 mm and a tooth pitch of 2 mm can be matched with a pulley with a module of 2 and 25 teeth, a tooth groove depth of 1.5 mm, and a meshing clearance of less than 0.1 mm. The inner diameter of the pulley matches the top shaft diameter of the Z-axis lead screw 92; for example, when the shaft diameter is 8 mm, the inner diameter of the pulley is machined to an 8H7 tolerance.

[0076] During assembly, the synchronous belt 94 is mounted around the pulley on the output shaft of the Z-axis drive motor 91 and between the pulleys at the top of the two Z-axis lead screws 92. The pulleys are fixed to the top of the Z-axis lead screws 92 via keyways or set screws to ensure synchronous rotation with the lead screws. Working process: When the Z-axis drive motor 91 starts, power is transmitted through the toothed engagement of the synchronous belt 94, driving the two Z-axis lead screws 92 to rotate synchronously. The toothed engagement design avoids slippage common in traditional belt drives, ensuring consistent lifting speeds of the sliders 93 on both sides. The polyurethane synchronous belt 94 has high wear resistance, and the toothed engagement reduces transmission slippage. The synchronization error of the two lead screws 92 is controlled within ±0.2mm, extending the service life of the equipment.

[0077] The tension adjustment device uses a commonly used tensioning mechanism, which may include an idler pulley and a tensioning bracket. The idler pulley has a diameter of 30-50mm and a bearing inner diameter of 8mm. The idler pulley is rotatably mounted on the tensioning bracket, which has an elongated hole. The tension adjustment screw passes through this hole to mount the tensioning bracket onto the crossbeam 32, allowing for position adjustment along the direction of the elongated hole (20-30mm). The tension adjustment screw is an M4 or M5 standard screw. Rotating the screw moves the tensioning bracket, thereby adjusting the preload of the idler pulley on the synchronous belt, and thus adjusting the tension of the synchronous belt 94. For example, during initial installation, the preload of the synchronous belt 94 is set to 50-80N. By adjusting the screw, the idler pulley is moved 5-10mm, ensuring the deflection of the synchronous belt 94 is less than 2mm.

[0078] During assembly, the idler pulley bracket is bolted to the crossbeam 32, located between the Z-axis drive motor 91 and the Z-axis lead screw (92) pulley; the tension adjusting screw is vertically installed on the tensioning bracket and locked in place by a nut. Working process: When the synchronous belt 94 becomes loose due to long-term use, tightening the tension adjusting screw pushes the tensioning bracket and idler pulley away from the pulley, increasing the tension of the synchronous belt 94 and restoring transmission rigidity. After adjustment, the locking screw prevents displacement of the tensioning bracket and idler pulley. The adjustable tensioning device adapts to the deformation of the synchronous belt 94 under different load conditions, maintains transmission stability, reduces vibration and noise caused by loosening, and has low maintenance costs.

[0079] In this embodiment, the precise meshing design of the toothed synchronous belt 94 and the pulley ensures the synchronous rotation of the double Z-axis lead screw 92, preventing the guide rail 4 from tilting. The wear-resistant polyurethane material is suitable for use in teaching equipment with frequent start-stop cycles. The combination design of the idler pulley and adjusting screw simplifies the tensioning operation. Teachers or students can quickly restore transmission accuracy by manual adjustment without the need for professional tools, thus improving the convenience of equipment maintenance.

[0080] Furthermore, in another technical solution, the two ends of the X-axis lead screw 72 are fixed to the two ends of the X-axis of the platform 1 through bearing seats and are engaged with the threaded holes at the bottom of the slide block 2; the X-axis drive motor 71 is electrically connected to the PLC controller 6 and is used to drive the slide block 2 to move along the X-axis of the platform 1.

[0081] Specifically, the bearing housings are symmetrically installed at both ends of the platform 1 in the X direction, 50-80mm from the edge of the platform; the X-direction lead screw 72 passes through the inner hole of the bearing housing. Working process: When the X-direction drive motor 71 drives the X-direction lead screw 72 to rotate, the lead screw maintains stable rotation through the support of the bearing housing, avoiding flexural deformation caused by the cantilever structure and ensuring the linear accuracy of the slide 2 movement.

[0082] The threaded hole at the bottom of the slide 2 matches the external thread of the X-direction lead screw 72, with a pitch of 2mm and a thread depth of 8-10mm. During assembly, the X-direction lead screw 72 passes through the threaded hole, forming a helical pair transmission with the slide 2. Working process: When the X-direction lead screw 72 rotates, it drives the slide 2 to move along the X-direction slide groove 11.

[0083] The X-axis drive motor 71 can be a 57 series two-phase stepper motor, maintaining a torque of 0.8-1.2 N·m and a step angle of 1.8°, and is directly connected to the X-axis lead screw 72 via a coupling. The motor driver microstepping is set to 16 microsteps, with a pulse frequency of 10-50 kHz, and is powered by a 24V DC power supply. Electrical connections use shielded twisted-pair cable, 1-2 m in length. The signal line is connected to the pulse output port (e.g., Y0 / Y1) of the PLC controller 6, and the grounding terminal is separately connected to the metal frame of platform 1.

[0084] During assembly, the X-axis drive motor 71 is fixed to one end of the platform 1 via an L-shaped bracket and is coaxially mounted with the X-axis lead screw 72. In operation, the PLC controller 6 sends pulse signals to the motor driver to control the rotation angle and speed of the X-axis drive motor 71, driving the slide 2 to move to the target position. The encoder feedback signal corrects the position deviation in real time, forming a closed-loop control.

[0085] In this implementation, the bearing seats at both ends support and enhance the rigidity of the lead screw, preventing positioning deviations caused by deflection, making it suitable for environments where teaching equipment is frequently disassembled and reassembled. The simplified integration of the stepper motor and PLC reduces control complexity, allowing students to intuitively understand motion control principles by modifying pulse parameters.

[0086] Furthermore, in another embodiment, the two ends of the Y-axis lead screw 82 are fixed to the two ends of the Y-axis of the guide rail 4 by bearing seats and are engaged with the threaded holes of the robot arm 5; the Y-axis drive motor 81 is electrically connected to the PLC controller 6 and is used to drive the robot arm 5 to move along the Y-axis of the guide rail 4.

[0087] Specifically, the Y-axis lead screw 82 can be a trapezoidal lead screw with a diameter of 6-8mm and a lead of 4-5mm. Its length is determined by the Y-axis travel of the guide rail 4, for example, 300-400mm. The bearing housing is made of cast iron and contains a deep groove ball bearing (6mm inner diameter), fixed to both ends of the guide rail 4 with M5 bolts. During installation, the parallelism between the Y-axis lead screw 82 and the side groove 41 of the guide rail 4 must be calibrated, with a straightness error of less than 0.1mm / m. Both ends of the Y-axis lead screw are machined into smooth shaft sections, 8-10mm in length, with an interference fit to the inner ring of the bearing to prevent axial movement.

[0088] During assembly, the bearing housings are symmetrically installed at both ends of the Y-axis of the guide rail 4, 30-50mm from the edge of the guide rail; the Y-axis lead screw 82 passes through the inner hole of the bearing housing and is fixed at both ends with lock nuts. Working process: When the Y-axis drive motor 81 drives the Y-axis lead screw 82 to rotate, the bearing housing provides stable support, reduces lead screw vibration, and ensures that the robot arm 5 slides smoothly along the guide rail 4.

[0089] The thread specification of the threaded hole of the robotic arm 5 matches that of the Y-axis lead screw 82, with a thread depth of 10-12mm. The clearance between the Y-axis lead screw 82 and the threaded hole is controlled within 0.05mm.

[0090] During assembly, the Y-axis lead screw 82 passes through the threaded hole of the robot arm 5, forming a helical transmission pair with the robot arm 5. Working process: When the Y-axis lead screw 82 rotates, the nut drives the robot arm 5 to move along the Y-axis side groove 41 of the guide rail 4.

[0091] The Y-axis drive motor 81 can be a 42 series stepper motor, maintaining a torque of 0.4-0.6 N·m and a step angle of 1.8°, and is directly connected to the Y-axis lead screw 82 via a flexible coupling. The motor driver microstepping is set to 8 microsteps, with a pulse frequency of 5-20 kHz, and is powered by a 24V DC power supply. Electrical connections use shielded twisted-pair cable; the signal line is connected to the pulse output port (e.g., Y2 / Y3) of the PLC controller 6, and the grounding terminal is connected to the metal frame of the guide rail 4.

[0092] During assembly, the Y-axis drive motor 81 is fixed to one end of the guide rail 4 via a U-shaped bracket and is coaxially mounted with the Y-axis lead screw 82. In operation, the PLC controller 6 sends pulse signals to the motor driver to control the rotation angle and speed of the Y-axis drive motor 81, driving the robotic arm 5 to move to the target position. The encoder provides real-time position data feedback, forming a closed-loop control.

[0093] In this implementation, the fixed bearing seats at both ends reduce the vibration of the lead screw, ensuring smooth Y-axis movement of the robotic arm 5 and preventing gripping deviation. The simplified control scheme of the stepper motor and PLC reduces hardware complexity, allowing students to intuitively learn motion control principles through the programming interface.

[0094] Furthermore, in another implementation scheme, such as Figure 1 and Figure 4 As shown, the robotic arm 5 is connected to the Y-axis lead screw 82 via a swing mechanism, the swing mechanism comprising:

[0095] The electric rotary seat 1001 has its fixed end threadedly connected to the Y-axis lead screw 82, and its rotating end fixedly connected to the robot arm 5; it is used to drive the robot arm 5 to rotate, such as... Figure 4 As shown in the middle M direction.

[0096] The rotating shaft 1002 passes through the U-shaped opening at the rotating end of the electric rotating seat 1001 and is fixed to the robot arm 5;

[0097] The first servo motor 1003 is fixed to the outside of the electric rotary base 1001, and its output end is coaxially connected to the rotating shaft 1002, used to drive the robotic arm 5 to rotate around the rotating shaft 1002; for example Figure 4 As shown in the N direction;

[0098] The second servo motor 1004 is fixed to the rotating shaft 1002, and its output end is fixed to the robotic arm 5. It is used to drive the robotic arm 5 to swing around an axis perpendicular to the rotating shaft 1002, such as... Figure 4 As shown in the P direction.

[0099] Specifically, the gyratory mechanism can adopt a modular assembly design. The fixed end of the electric rotary seat 1001 is provided with an M6 threaded hole, which is connected to the nut of the Y-axis lead screw 82 through thread engagement. The rotating end is fixed to the base of the robot arm 5 via a flange. The flange has a diameter of 40-50mm and a thickness of 5-8mm, and is made of aluminum alloy to reduce weight.

[0100] During assembly, the fixed end of the electric rotary seat 1001 is connected to the Y-axis lead screw 82 via a threaded hole; the flange of the rotating end of the electric rotary seat 1001 is fixed to the base of the robot arm 5 with four M4 bolts; the rotating shaft 1002 horizontally passes through the two side walls of the U-shaped opening of the electric rotary seat 1001. Working process: When the electric rotary seat 1001 is powered on, its rotating end rotates relative to the fixed end around the axis of the Y-axis lead screw 82, driving the robot arm 5 to achieve rotational movement in the horizontal plane. The modular design simplifies the disassembly and assembly of the pendulum mechanism and meets the needs of teaching demonstrations.

[0101] The electric rotary table 1001 can be a rotary platform with an integrated geared stepper motor, a reduction ratio of 10:1, an output torque of 2-3 N·m, and a step angle of 0.9°. The U-shaped opening width is 15-20 mm, and a through hole with a diameter of 8 mm is machined at the end of the opening for mounting the rotating shaft 1002. The electrical interface of the electric rotary table is a 4-pin aviation connector, supporting PWM signal input and a power supply voltage of 12-24V DC.

[0102] During assembly, the fixed end of the electric rotary base 1001 is connected to the Y-axis lead screw 82 via a threaded hole; the rotating shaft 1002 passes through the through hole of the U-shaped opening and is fixed at both ends by snap rings; the first servo motor 1003 is fixed to the outside of the U-shaped opening with screws and is coaxially connected to the rotating shaft 1002. Working process: The PLC controller 6 sends a PWM signal to the electric rotary base 1001, driving its rotating end to rotate around the axis of the Y-axis lead screw 82, thereby driving the robotic arm 5 to adjust the azimuth angle.

[0103] The rotating shaft 1002 can be made of 45# steel with a diameter of 8mm and chrome-plated surface to enhance wear resistance, with a length of 50-60mm. The first servo motor 1003 is a metal gear servo motor with a torque range of 8-12 kg·cm, a rotation angle of 0-180°, and a response speed of 0.1s / 60°. The second servo motor 1004 is fixed to the middle or end of the rotating shaft 1002 via a bracket, with its output shaft perpendicular to the rotating shaft 1002, a torque of 6-8 kg·cm, and is used to drive the swing of the gripper of the robotic arm 5. The servo motor signal cable uses a 3-core shielded cable and is connected to the PWM output port of the PLC controller 6.

[0104] During assembly, the two ends of the rotating shaft 1002 are supported by flange bearings, and the bearing housing is fixed to the outside of the U-shaped opening of the electric rotating seat 1001; the housing of the first servo motor 1003 is fixed to one side of the U-shaped opening by M3 screws, and the output shaft is connected to the rotating shaft 1002 by a keyway; the second servo motor 1004 is installed in the middle or end of the rotating shaft 1002 by a bracket, and the output shaft is connected to the robot arm 5.

[0105] Working process: After receiving the PLC signal, the first servo motor 1003 drives the rotating shaft 1002 to rotate, causing the robot arm 5 to swing around the axis of the rotating shaft (such as adjusting the pitch angle); the second servo motor 1004 controls the swing of the end gripper of the robot arm 5 around the vertical axis, realizing multi-degree-of-freedom movement.

[0106] The dual-servo motor split-axis control in this embodiment enables multi-directional movement of the robot arm 5, enhancing students' understanding of multi-degree-of-freedom collaborative control and improving the intuitiveness of teaching.

[0107] Furthermore, in another embodiment, the electric rotary base 1001, the first servo motor 1003 and the second servo motor 1004 are all electrically connected to the PLC controller 6 to realize multi-degree-of-freedom motion control of the robot arm 5.

[0108] Specifically, the electric rotary base 1001 can use a 4-pin aviation connector as the electrical interface, with a 0.5mm² shielded cable. Two wires are used for power (12-24V DC), and the other two are used for PWM signal transmission. The power lines of the first servo motor 1003 and the second servo motor 1004 can be connected in parallel to the DC output terminal of the PLC controller 6, and the signal lines are respectively connected to the PLC's PWM output channels (such as Y10 / Y11). The grounding terminal of the shielding layer is uniformly connected to the metal frame of the platform 1, with a grounding resistance of less than 1Ω. The cable length is cut to 0.5-1.5m according to the actual layout, and the redundant part is fixed to the side of the guide rail 4 with nylon cable ties.

[0109] In one working process: PLC controller 6 sends rotation angle commands to electric rotary base 1001 through a preset program, and simultaneously sends PWM pulse width signals to servo motors (first servo motor 1003 and second servo motor 1004) to control the rotation and swinging movements of robotic arm 5. Signal transmission delay is less than 10ms, ensuring synchronized multi-axis movements. Integrated wiring reduces cable clutter and the risk of signal interference. Students can directly adjust the timing of each unit's actions through the PLC program, improving the intuitiveness of the control logic.

[0110] The program for PLC controller 6 can be programmed using ladder logic, enabling multi-task parallel processing. The rotation angle of the electric rotary seat 1001 is controlled by closed-loop feedback through pulse counting. The angles of the first servo motor 1003 and the second servo motor 1004 are controlled by PWM duty cycle, ranging from 5-10% (corresponding to 0°) to 10-15% (corresponding to 180°). In the motion synchronization logic, the start delay of the rotary seat 1001 and servo motors 1003 and 1004 is set to 0-50ms to avoid current surges caused by simultaneous start-stop. For example, the gripping motion of the robotic arm 5 is as follows: the rotary seat 1001 rotates to the target angle → the first servo motor 1003 adjusts the pitch angle → the second servo motor 1004 controls the gripper to close.

[0111] During assembly, the program module of PLC controller 6 is connected to the host computer via an Ethernet interface, supporting online debugging; the action logic parameters are stored in the PLC's EEPROM and are not lost when power is off. Working process: After the student inputs the target action sequence through the operation panel, PLC controller 6 sends control signals according to preset logic in a time-division manner, driving the electric rotary base 1001 and the servo motors (first servo motor 1003, second servo motor 1004) to move sequentially, and corrects position deviations in real time through encoder feedback.

[0112] Furthermore, in another embodiment, the PLC controller 6 is equipped with a programming interface and an operation panel for inputting coordinate commands and controlling the positioning and grasping operations of the robot arm 5 in three-dimensional space.

[0113] Specifically, the programming interface of PLC controller 6 can be RS485, Ethernet, or USB 2.0, supporting Modbus RTU and TCP / IP communication protocols. For example, the RS485 interface baud rate can be set to 9600-115200bps, with 8 data bits, 1 stop bit, and no parity. The Ethernet interface supports 10 / 100M auto-sensing, and the IP address can be manually configured via the operation panel. The USB interface is used to connect to a host computer, supporting program download and real-time monitoring.

[0114] Working process: Students connect to the computer via USB interface, use programming software to write control logic and download it to the PLC; during operation, the Ethernet interface is used to communicate with external devices (such as a teach pendant) to transmit the position data of the robot arm 5 in real time.

[0115] The control panel can be a 7-inch resistive touchscreen with a resolution of 800×480, covered with a tempered glass protective layer with a thickness of 1.5-2mm. The interface is divided into a coordinate input area, a motion control area, and a status display area. The coordinate input area supports manual input of X / Y / Z axis target values ​​with an accuracy of 0.1mm; the motion control area has "Start," "Stop," and "Reset" buttons, with a button size of 15×15mm and clear tactile feedback; the status display area displays the position, speed, and alarm information of the robotic arm 5 in real time, with a font size of 14pt and adjustable contrast. The panel is powered by 5V DC, with a power consumption of less than 3W, and is connected to the PLC controller 6 mainboard via a ribbon cable.

[0116] Working process: After inputting the target coordinates via the touchscreen, the student clicks the "Start" button. The PLC controller 6 parses the instructions and drives the robotic arm 5 to move. During the movement, the current position data is updated and displayed in real time, and an alarm is triggered by an abnormal state. The intuitive interactive interface lowers the operating threshold, allowing students to complete basic programming and motion control without professional training, thus improving teaching efficiency.

[0117] The program memory of PLC controller 6 can be an EEPROM chip with a capacity of 32KB, supporting 1 million erase / write cycles. The control logic employs multi-threaded processing; the main thread handles coordinate analysis and motion control, while sub-threads handle status monitoring and alarms. Data interaction is achieved through shared memory with a refresh cycle of 10ms. For example, when new coordinates are input on the operation panel, the PLC immediately interrupts the current task, recalculates the motion trajectory, and adjusts the drive motor speed via pulse signals. Alarm conditions include position deviation (±2mm), motor overcurrent (>1.5A), and communication timeout (>500ms). Upon triggering these conditions, the operation automatically pauses and the panel warning light illuminates.

[0118] During assembly, the EEPROM chip is connected to the main board of PLC controller 6; the buzzer and warning light are installed in the upper right corner of the operation panel and connected to the main board via jumpers. Operation process: After receiving commands from the operation panel, PLC controller 6 calls a preset motion algorithm to generate pulse signals, synchronously controlling the X / Y / Z axis drive motors and servo motors; simultaneously, it monitors the feedback data from each sensor in real time, immediately interrupting and alerting if any abnormality occurs.

[0119] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A PLC-based multi-degree-of-freedom robotic arm teaching aid, characterized in that, include: Platform (1); The slide (2) is slidably connected to the platform (1) in the X direction, and the bottom of the slide (2) is provided with a protrusion that cooperates with the X-direction slide groove (11) of the platform (1); The gantry support (3) is set on the upper side of the slide (2) and includes two columns (31) and a crossbeam (32). The columns (31) are fixed to both sides of the slide (2) along the Y direction, and the crossbeam (32) is horizontally connected to the upper ends of the two columns (31). The guide rail (4) is slidably disposed between two columns (31) along the Z direction. The side wall of the guide rail (4) is provided with a Y-direction side groove (41) for the robot arm (5) to slide. The robotic arm (5) is slidably connected to the Y-direction side groove (41) of the guide rail (4); The X-axis drive mechanism is set on the platform (1) and includes an X-axis drive motor (71) and an X-axis lead screw (72). The X-axis lead screw (72) is threadedly connected to the slide (2). The Y-axis drive mechanism is mounted on the guide rail (4) and includes a Y-axis drive motor (81) and a Y-axis lead screw (82). The Y-axis lead screw (82) is threadedly connected to the robot (5). The Z-axis drive mechanism, which is mounted on the gantry bracket (3), includes: Z-axis drive motor (91), which is fixed to the crossbeam (32); Two Z-axis lead screws (92) are rotatably and vertically mounted on the inner side of two columns (31) via bearings, and a synchronous pulley is fixed at the top of each Z-axis lead screw (92); A synchronous belt (94) is meshed between the synchronous pulley of the output shaft of the Z-axis drive motor (91) and the synchronous pulleys of the two Z-axis lead screws (92); The slider (93) has two parts, which are slidably connected to the column (31) on the same side along the Z direction and threadedly connected to the corresponding Z-direction screw (92); The two ends of the guide rail (4) are fixedly connected to the slider (93) on the same side respectively; The PLC controller (6) is fixed on the platform (1) and electrically connected to the robot (5), the X-axis drive motor (71), the Y-axis drive motor (81), and the Z-axis drive motor (91).

2. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 1, characterized in that, The synchronous belt (94) is a toothed synchronous belt, and the synchronous pulley is a toothed pulley that matches the toothed synchronous belt; the synchronous belt (94) is also provided with a tension adjustment device (95), including a movable adjustable idler pulley or tension pulley.

3. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 1, characterized in that, The two ends of the X-axis lead screw (72) are fixed to the two ends of the X-axis of the platform (1) through bearing seats and are engaged with the threaded holes at the bottom of the slide (2); the X-axis drive motor (71) is electrically connected to the PLC controller (6) and is used to drive the slide (2) to move along the X-axis of the platform (1).

4. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 1, characterized in that, The two ends of the Y-axis lead screw (82) are fixed to the two ends of the Y-axis of the guide rail (4) through bearing seats and are engaged with the threaded holes of the robot (5); the Y-axis drive motor (81) is electrically connected to the PLC controller (6) and is used to drive the robot (5) to move along the Y-axis of the guide rail (4).

5. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 1, characterized in that, The robotic arm (5) is connected to the Y-axis lead screw (82) via a swing mechanism, the swing mechanism comprising: The electric rotary seat (1001) has its fixed end threadedly connected to the Y-axis lead screw (82) and its rotating end fixedly connected to the robot (5); A rotating shaft (1002) passes through the U-shaped opening at the rotating end of the electric rotating seat (1001) and is fixed to the robot arm (5); The first servo motor (1003) is fixed outside the electric rotary base (1001), and its output end is coaxially connected to the rotating shaft (1002) to drive the robot arm (5) to rotate around the rotating shaft (1002); The second servo motor (1004) is fixed on the rotating shaft (1002), and its output end is fixed to the robot arm (5) to drive the robot arm (5) to swing around an axis perpendicular to the rotating shaft (1002).

6. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 5, characterized in that, The electric rotary base (1001), the first servo motor (1003) and the second servo motor (1004) are all electrically connected to the PLC controller (6) to realize the multi-degree-of-freedom motion control of the robot (5).

7. The PLC-based multi-degree-of-freedom robotic arm teaching aid according to claim 1, characterized in that, The PLC controller (6) is equipped with a programming interface and an operation panel for inputting coordinate commands and controlling the positioning and grasping operations of the robot (5) in three-dimensional space.

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