Tendon-type rope-driven robot arm

Abstract

The application discloses a tendon type rope-driven mechanical arm, which comprises an arm rod, a sling, a rotating joint, a driving device and a rope, the rotating joint is fixedly connected with the sling and forms a cross-shaped structure, the driving device is arranged in each of the two arm rods, and the application further comprises a pre-tightening device, the rotating joint comprises two rotating shafts, the two rotating shafts are arranged on the two sides of the middle part of the sling in a direction perpendicular to the sling, and one end of each of the two arm rods is connected with the two rotating shafts respectively. In the application, four steel wires are simultaneously driven by four motors, a complete antagonistic structure is formed, the structural rigidity of the mechanical arm is improved, a guide wheel is arranged on the rotating joint, interference between the rope and the equipment on the rotating joint is avoided, the transmission reliability of the mechanical arm is improved, the tension of the whole rope can be adjusted through the arrangement of the pre-tightening device, and the transmission precision of the whole mechanical arm is improved.

Description

Technical Field

[0001] This invention relates to the field of robotic arm construction technology, and more specifically to a tendon-type cable-driven robotic arm. Background Technology

[0002] Current robotic arms connect their various levers via rotary joints. These joints are driven by motors through gear trains, which apply joint torque relatively close to the joint axis. When higher joint torque is required, high-torque motors and large gear transmission systems are necessary. Therefore, the rotary joints account for a significant portion of the robotic arm's mass. Furthermore, the area around the rotary joint becomes very congested due to the need for electrical wiring harnesses to transmit power, sensor data, control, and video signals between the joint and the end effector, further complicating the design.

[0003] To increase the operating range of traditional robotic arms, one must either increase the number of rotary joints or increase the length of each arm. Because rotary joints are relatively heavy, increasing the number of joints significantly increases the weight of the robotic arm. Increasing the arm length requires increasing the torque of the rotary joints; even using high-torque motors and large gear transmission systems still greatly increases the weight of the robotic arm. Therefore, the operating range of traditional robotic arms is very limited.

[0004] Patent document CN115488871A discloses a lightweight, high-torque tendon-driven single-degree-of-freedom mechanical joint device, including a rotary joint, a boom, two arms, a drive module, and drive ropes. The rotary joint includes two pivots offset on both sides of the middle section of the boom, perpendicular to the boom direction. One end of each arm is connected to one of the pivots. The drive ropes are routed in an antagonistic manner between the other ends of the arms and the ends of the boom. The drive module connects to the drive ropes and controls their extension and retraction lengths. The tension of the drive ropes acts on the ends of the boom, thereby driving the rotary joint and the two arms to rotate synchronously. This joint structure helps reduce modeling complexity, improve control accuracy, weaken or avoid motion coupling between joints, and has a large range of motion. The boom can increase the drive arm, increasing the output torque. Antagonistic rope control can change the joint stiffness characteristics. The ultra-light weight and excellent extension / retraction ratio enable rapid deployment and application.

[0005] The device is driven by two or four motors and consists of a boom, drive unit, spring tensioning structure, swivel joint, lifting device, and wire rope. The drive unit and spring tensioning structure are installed inside the boom; each boom has a drive wire rope, whose route is as follows: pulley at one end of the lifting device, pulley block on the boom, winch of the drive unit, and pulley at the other end of the lifting device.

[0006] The most distinctive feature of tendon-type chord-driven robotic arms is that they move via cables. During operation, the cables must remain taut at all times. (See also...) Figure 1 , Figure 1 The simplified diagram of the tendon-type rope-driven robotic arm is shown below. Let β be the angle between the robotic arm and the lifting device, and let the lengths of the four ropes be L1, L2, L3, and L4. To improve the stress distribution on the lifting device, it is typically designed to withstand only tension or compression along the direction of the lifting arm during operation. Therefore, two conditions must be met: 1) The angle between the lifting device and the ropes on both sides must always be equal;

[0007] 2) The tension on the ropes on both sides of the lifting device is always equal;

[0008] Assuming that the lengths of all boom segments are equal, from 1), we can obtain:

[0009] L1 = L3 1.1

[0010] L2 = L4 1.2

[0011] Let the length of one side of the lifting device be h, and the length of the boom be a. By the law of cosines, we know that:

[0012]

[0013]

[0014] Therefore, the length of the rope on the left is:

[0015]

[0016] As can be seen from the above formula, the length of the rope is related to the included angle β, and the included angle β changes with the rotation of the robotic arm. Therefore, the length of the rope changes constantly with the rotation of the robotic arm, so a rope compensation device needs to be introduced. However, the spring tension used in this scheme will change with the spring elongation. When the spring elongation is small, the tension on the wire rope will decrease, and the wire rope will easily slack off. At the same time, the use of dual motor drive results in low rigidity of the entire robotic arm structure. Summary of the Invention

[0017] The technical problem to be solved by this invention is how to improve the structural rigidity of the entire rope-driven robotic arm.

[0018] This invention solves the above-mentioned technical problems through the following technical means: a tendon-type rope-driven robotic arm, comprising a boom, a lifting device, a rotary joint, a drive device, and a rope. The rotary joint is fixedly connected to the lifting device and forms a cross-shaped structure. Each of the two booms is equipped with a drive device. The invention is characterized by further including a pre-tensioning device. The rotary joint includes two rotating shafts, which are offsetly disposed on both sides of the middle portion of the lifting device in a direction perpendicular to the lifting device. One end of each of the two booms is connected to the two rotating shafts. Each of the two drive devices includes two sets of drive motors. The four sets of drive motors are used to simultaneously drive the rope transmission and cause the rotary joint and the two booms to rotate independently. The rope is laid in a completely antagonistic manner between the ends of the two booms away from the lifting device and the two ends of the lifting device. The rope is also connected to the end of the lifting device through the pre-tensioning device, which includes a fixed plate and a rope clamping plate. The rope clamping plate is movable relative to the fixed plate and is fixedly connected to the rope. The rotary joint is also equipped with a guide wheel adapted to the rope.

[0019] By using four motors to simultaneously drive four steel wire ropes, a completely antagonistic structure is formed, which improves the structural rigidity of the robotic arm. At the same time, guide wheels are set on the rotary joints to prevent interference between the ropes and the equipment on the rotary joints, thereby improving the transmission reliability of the robotic arm.

[0020] As a preferred technical solution, the lifting device includes a side plate, a horizontal plate, a vertical plate, a rotating shaft, and a tension gauge. One of the horizontal plates is fixedly connected to another horizontal plate through a vertical plate. A side plate is fixedly connected to the vertical plate. The free end of the side plate is rotatably connected to the rotating shaft. The tension gauge is connected to the rope through the rotating shaft.

[0021] As a preferred technical solution, the fixing plate includes a pre-tightening rotating plate, one end of which is fixedly connected to a tension gauge, and the other end is threadedly connected to a pre-tightening screw, which is fixedly connected to a rope clamping plate.

[0022] As a preferred technical solution, the rope clamping plate includes a pressure plate and a perforated plate. The perforated plate has at least one perforation adapted to the rope, through which the rope passes. The pressure plate is fixedly connected to the perforated plate by bolts.

[0023] As a preferred technical solution, the end of the pre-tightening rotating plate connected to the tension gauge is also fixedly connected to a fixed optical axis, and the pre-tightening rotating plate is connected and fastened to the tension gauge through the fixed optical axis.

[0024] As a preferred technical solution, the driving device includes a driving bracket, a driving motor, and a drum. The driving bracket is fixedly connected inside the arm, and the top and bottom of the driving bracket are respectively fixedly connected to the driving motor. The output end of the driving motor is connected to the drum, and the drum is connected to the rope.

[0025] As a preferred technical solution, the free end of the vertical plate is fixedly connected to a bearing seat, and the bearing seat is rotatably engaged with the rotating shaft.

[0026] As a preferred technical solution, the boom is formed by splicing together a truss or frame structure.

[0027] As a preferred technical solution, the system also includes a pulley block, which includes two first pulleys and a second pulley. Both the first pulley and the second pulley are rotatably connected inside the boom and are located on both sides of the rope tensioning device.

[0028] As a preferred technical solution, the drum includes a first drum and a second drum. After the rope is wound around the first drum, the fixed end of the rope is connected to the lifting device through a roller, the second drum, and a second pulley.

[0029] The advantages of this invention are:

[0030] (1) In this invention, four steel wire ropes are driven by four motors at the same time, forming a completely antagonistic structure, which improves the structural rigidity of the robotic arm. At the same time, guide wheels are set on the rotating joints to avoid interference between the ropes and the equipment on the rotating joints, thereby improving the transmission reliability of the robotic arm.

[0031] (2) In this invention, the roller is elastically connected to the U-shaped bracket by the spring, and the rope is passed through the roller, so that the roller becomes a movable pulley. Its moving distance is half of the change in the length of the wire rope, which can adapt to a larger change in the length of the wire rope. At the same time, the spring can compensate for the change in the rope.

[0032] (3) In this invention, by setting up a fixed plate and a rope clamping plate, and enabling the rope clamping plate to move relative to the fixed plate, the tension of the entire rope can be adjusted, thereby improving the transmission accuracy of the entire robotic arm. Attached Figure Description

[0033] Figure 1 A schematic diagram of a tendon-type cable-driven robotic arm structure provided for the background art of this invention;

[0034] Figure 2 This is a schematic diagram of the overall structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the internal structure of a tendon-type cable-driven robotic arm provided in an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the cable routing of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0037] Figure 5 This is a top view schematic diagram of the rope structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the axial structure of a lifting device for a tendon-type rope-driven robotic arm, provided in an embodiment of the present invention.

[0039] Figure 7 This is a schematic diagram of the lifting device structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0040] Figure 8 A schematic diagram of a pretensioning device for a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0041] Figure 9 This is an exploded structural diagram of a pretensioning device for a tendon-type rope-driven robotic arm, provided in an embodiment of the present invention.

[0042] Figure 10 A schematic diagram of the rotary joint structure of a tendon-type cable-driven robotic arm provided in an embodiment of the present invention;

[0043] Figure 11 This is a schematic diagram of the rope tensioning device structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0044] Figure 12 A schematic diagram of the drive device structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0045] Figure 13 This is a schematic diagram of a pulley block structure for a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0046] Figure 14 A schematic diagram of force analysis for a tendon-type cable-driven robotic arm provided in an embodiment of the present invention;

[0047] Figure 15 A schematic diagram of the drum structure of a tendon-type rope-driven robotic arm provided in an embodiment of the present invention;

[0048] Icon labels:

[0049] 1. Boom; 2. Lifting Gear; 201. Horizontal Plate; 202. Side Plate; 203. Bearing Seat; 204. Rotating Shaft; 205. Force Gauge; 206. Vertical Plate; 3. Rotary Joint; 301. Joint Rotating Shaft Plate; 302. Joint Frame; 303. First Connecting Plate; 304. Encoder; 305. Guide Wheel Assembly; 4. Rope Tensioning Device; 401. Fixing Plate; 402. Linear Guide Rail; 403. Slider; 404. Second Connecting Plate; 405. Pulley; 406. Spring; 407. First limit stop; 408. Second limit stop; 5. Drive device; 501. Drive bracket; 502. Drive motor; 5021. First motor; 5022. Second motor; 503. Winch; 504. Gear set; 505. Drum; 6. Pulley block; 7. Pre-tightening device; 701. Fixed optical shaft; 702. Pre-tightening rotating plate; 703. Pre-tightening screw; 704. Pressure plate; 705. Perforated plate; 8. Rope. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0051] See Figure 2 , Figure 3 A tendon-type rope-driven robotic arm includes a boom 1, a lifting device 2, a rotary joint 3, a rope tensioning device 4, a drive device 5, a pulley block 6, a pre-tensioning device 7, and a rope 8. A boom 1 is rotatably connected to each end of the rotary joint 3. The lifting device 2 is fixedly connected to the center of the rotary joint 3. The end of the boom 1 facing away from the rotary joint 3 is sequentially equipped with the pulley block 6, the rope tensioning device 4, and the drive device 5. The drive device 5 is the drive unit for the entire robotic arm, used to drive the rope 8. The rope tensioning device 4 compensates for rope variations. The end of the lifting device 2 is connected to the rope 8 via the pre-tensioning device 7. The pulley block 6 is used to prevent the rope 8 from interfering with other equipment during the rotation of the robotic arm. In this embodiment, the rope 8 is a steel wire rope, and one steel wire rope is installed on the boom 1. (See reference...) Figure 4 , Figure 5 The rope 8 is laid in a completely antagonistic manner between the two booms 1 at one end away from the lifting device 2 and the two ends of the lifting device 2. The wire rope route is as follows: the pre-tensioning device 7 at one end of the lifting device 2, the pulley block 6 on the boom 1, the winch of the drive device 5, the pulley of the rope tensioning device 4, the winch of the drive device 5, the pulley block 6 on the boom 1, and the pre-tensioning device 7 at the other end of the lifting device 2. The boom 1 is formed by splicing together a truss or frame structure.

[0052] See Figure 6 , Figure 7 The lifting device 2 includes a horizontal plate 201, a side plate 202, a bearing seat 203, a rotating shaft 204, a tension gauge 205, and a vertical plate 206. One horizontal plate 201 is fixedly connected to another horizontal plate 201 through two vertical plates 206, forming the frame structure of the lifting device 2. The two vertical plates 206 are fixedly connected to the opposite ends of each other by a side plate 202. A bearing seat 203 is fixedly connected to each side plate 202, and a rotating shaft 204 is rotatably connected to the bearing seat 203. A tension gauge 205 is fixedly connected to the wire rope on each side of the rotating shaft 204. The tension gauge 205 can read the preload on the wire rope in real time. The setting of the rotating shaft 204 can ensure that the tension gauge 205 can rotate freely around the lifting device 2. This ensures that when the robotic arm rotates, the axis of the wire rope and the tension gauge 205 are always collinear, ensuring that the reading of the tension gauge 205 is equal to the tension on the wire rope.

[0053] See Figure 8 , Figure 9 The tension gauge 205 is also connected to the wire rope via a pre-tensioning device 7. The pre-tensioning device 7 can adjust the pre-tension force on the wire rope, thereby ensuring the movement accuracy of the robotic arm. One end of the tension gauge 205 is fixed to the pre-tensioning device 7, and the other end is fixed to the rotating shaft 204. The pre-tensioning device 7 includes a fixed optical shaft 701, a pre-tensioning rotating plate 702, a pre-tensioning screw 703, a pressure plate 704, and a perforated plate 705. In this embodiment, the fixed plate is the pre-tensioning rotating plate 702, and the rope clamping plate includes the pressure plate 704 and the perforated plate 705. The pre-tensioning rotating plate 702 can be a rectangular frame structure, but it is not limited to this and can also be a frame of other shapes. The frame has a pre-tightening rotating plate 702 with a fixed optical shaft 701 fixedly connected to one end, and a tension gauge 205 connected to the fixed optical shaft 701. The other end of the pre-tightening rotating plate 702 is threadedly connected to a pre-tightening screw 703, and a perforated plate 705 is fixedly connected to the pre-tightening screw 703. The perforated plate 705 has at least one perforation, which allows the wire rope to pass through. In this embodiment, one perforation is used as an example, but it is not limited to this. The pressure plate 704 is fixed to the perforated plate 705 by bolts to achieve the clamping of the wire rope. When the pre-tightening rotating plate 702 is rotated, the pre-tightening screw 703 will move along the axial direction, thereby tightening the wire rope.

[0054] It should be noted that the pre-tensioning rotating plate 702 and pre-tensioning screw 703 in the pre-tensioning device 7 can also be bolts and nuts, threaded rods and threaded sleeves, or other threaded connection structures. Taking bolts and nuts as an example, the end of the tension gauge 205 connected to the pre-tensioning device 7 is fixedly connected to a bolt, and the end of the rope 8 is connected to a nut. The tension of the rope can also be adjusted by the cooperation of the bolt and nut.

[0055] See Figure 10The rotary joint 3 includes a joint pivot plate 301, a joint frame 302, a first connecting plate 303, an encoder 304, and a guide wheel assembly 305. The rotary joint 3 is used to connect the two arms 1 and provide a degree of freedom for the entire robotic arm. The joint frame 302 is fixedly connected to a joint pivot plate 301 at its top and bottom, forming an I-shaped structure. A first connecting plate 303 is rotatably connected to each end of the structure. The two first connecting plates 303 and the joint pivot plate 301 are rotatably connected to form a rotary shaft A and a rotary shaft B, respectively. The two rotary shafts are offset from the lifting device 2 in a direction perpendicular to the lifting device 2. On both sides of the middle part, two first connecting plates 303 are fixedly connected to two arms 1 respectively. The center distance between the two rotating shafts of the joint frame 302 must be greater than the width of the connecting plate to achieve ±180° rotation. Two sets of guide wheel sets 305 are installed on each first connecting plate 303 to prevent the wire rope from interfering with the first connecting plate 303 during the rotation of the robotic arm. Encoders 304 are installed on both rotating shaft A and rotating shaft B. The encoders 304 are used to read the rotation angle of the two first connecting plates 303. The horizontal plate 201 is fixedly connected to the joint rotating shaft plate 301 at the middle.

[0056] See Figure 11 The rope tensioning device 4 includes a fixed plate 401, a linear guide rail 402, a slider 403, a second connecting plate 404, a pulley 405, a spring 406, a first limiting block 407, and a second limiting block 408. A linear guide rail 402 is fixedly connected to both the top and bottom of the fixed plate 401, forming a U-shaped support. The linear guide rail 402 forms the horizontal section of the U-shaped support, and the fixed plate 401 forms the vertical section. The linear guide rail 402 is fixedly connected to the top and bottom inner walls of the arm 1, respectively. A slider 403 is slidably connected to the linear guide rail 402, and a pulley 405 is provided between the two sliders 403. The two ends of the pulley 405 are connected to a slider 403 via a second connecting plate 404. After the pulley 405 is fixed to the two second connecting plates 404, it forms a movable support. The second connecting plates 404 are also elastically connected to the fixed plate 401 through multiple springs 406. The right end of the linear guide rail 402 is fixedly connected to the second limit block 408, and the left end is fixedly connected to the first limit block 407. The pulley 405 has a groove formed on it. The wire rope is wound in the groove of the pulley 405. When the length of the wire rope changes, the pulley 405 will move along the linear guide rail 402 under the combined action of the springs 406 and the wire rope, so that the wire rope is always in a taut state. It should be noted that the pulley 405 in this article is a movable pulley, and its moving distance is half of the change in the length of the wire rope. Therefore, it can adapt to a larger change in the length of the wire rope.

[0057] The pulley block 6 is rotatably connected inside the boom 1 and is located on both sides of the fixed plate 401. The pulley block 6 includes two first pulleys and two second pulleys, and both the first pulleys and the second pulleys are rotatably engaged with the boom 1.

[0058] See Figure 12 , Figure 13 The drive unit 5 is fixed inside the boom 1. The boom 1 has a through hole for the rope 8 to drive. The drive unit 5 includes a drive bracket 501, two drive motors 502, a winch 503, and two gear sets 504. The drive bracket 501 is fixedly connected inside the boom 1. Two drive motors 502 are fixedly connected to the drive bracket 501, and the two drive motors 502 are symmetrically arranged. Two winches 503 are rotatably connected to the upper middle part of the drive bracket 501. The output ends of the drive motors 502 are connected to the winches 503 through the gear sets 504. The two drive motors 502 are respectively connected to the two gear sets 504. The pulley set 504 is driven by two winches 503. Each winch 503 is a mechanical device that winds but does not store rope under power. Each winch 503 has rope grooves in which the wire rope is wound. The winch 503 drives the wire rope through friction between itself and the wire rope. The friction between the winch 503 and the wire rope is positively correlated with the tension in the wire rope. The two winches 503 can rotate independently. Two motors drive the winches 503 to rotate through gear sets 504. Each winch 503 includes a first winch and a second winch, with the first winch located on top of the second winch. (See reference...) Figure 13 The cable path of the rope 8 between the rope tensioning device 4 and the drive device 5 is b, c, d, e, f, g in sequence; that is, the two first pulleys of the pulley block 6 pass through the first winch, pulley 405, second winch, and two second pulleys in sequence.

[0059] See Figure 15 Alternatively, a drum 505 can be used instead of a winch 503. The drum 505 can drive and store the wire rope, thus eliminating the need for the rope tensioning device 4. Excess wire rope can be directly wound onto the drum 505. The drive device 5 includes a drive bracket 501, a drive motor 502, and a drum 505. The drive bracket 501 serves as a mounting bracket for the drive motor 502. The drive bracket 501 is fixedly connected inside the boom 1. The boom 1 can be a truss or frame structure. The drive bracket 501 is fixedly connected to the middle of the boom 1. A drive motor 502 is fixedly connected to the top and bottom of the drive bracket 501, respectively. The output ends of the drive motor 502 are all connected to the drum 505.

[0060] The use of drum 505 avoids the defect of wire rope slippage. In addition, the rope tensioning device 4 can be removed. This solution simplifies the wire rope winding, thus avoiding the defect of spring tension variation and reducing friction in the wire rope line. The system has high efficiency and strong load capacity. Moreover, removing the rope tensioning device 4 also reduces the weight of the whole machine and lowers the overall cost.

[0061] See Figure 14 Let the length of one side of the lifting device 2 be h, the length of the boom 1 be a, the length of the rope 8 be l, the angle between the lifting device 2 and the rope 8 be α, and the tension in the rope 8 be F. With the left boom 1 fixed, the two lower ropes 8 are simultaneously pulled, causing the robotic arm to rotate clockwise. From the force analysis, the joint torque of the tendon-type rope-driven robotic arm shown in the diagram is:

[0062] M 关 =2Fhsinα

[0063] As can be seen from the above formula, the joint torque of the tendon-type cable-driven robotic arm is positively correlated with the length of the lifting device 2: under the same cable tension, the longer the lifting device 2 is, the greater the joint torque of the tendon-type cable-driven robotic arm, that is, the lifting device 2 plays the role of increasing the lever arm.

[0064] Tendon drives replace the high-torque motor gearboxes of traditional robotic arms with ropes, easily enabling long-distance transmission with reduced mass and higher structural efficiency. Tendon drives also incorporate structures that increase the lever arm, making the lever arm between the rope force and the joint rotation axis longer, thereby generating greater joint torque.

[0065] Operating Method: Four-motor time-sharing drive: Taking two drive motors 502 on one boom 1 as an example, namely the first motor 5021 and the second motor 5022, it can be seen from equations 1.3-1.4 that during the rotation of the lifting device 2, the length changes of the wire ropes L1 and L2 are different and constantly changing. Therefore, the speed ratio of the first motor 5021 and the second motor 5022 is always changing. For ease of control, the two drive motors 502 adopt time-sharing drive. When the first motor 5021 drives the wire rope L2 to rotate the lifting device through the first winch, the second motor 5022 is de-energized. Then the second winch is equivalent to a pulley and can rotate freely. The other end of the lifting device 2 will drive the second winch to rotate through the wire rope L1. At this time, the second motor 5022 is in a passive state. Conversely, when the second motor 5022 is powered on, the first motor 5021 is powered off and put in a passive state, and the lifting device 2 will reverse. This allows the motor speed at the passive end to adapt to the motor speed at the active end, simplifying the control algorithm. Similarly, the two drive motors 502 on the other boom 1 are driven in the same way as described above.

[0066] It should be noted that the rope-driven robotic arm in this embodiment can also be driven by four drive motors 502 simultaneously. The four drive motors 502 simultaneously drive four steel wire ropes, which is a completely antagonistic structure with high structural rigidity. When the four drive motors 502 are driving, a drum 505 is used instead of a winch 503. When the winch 503 is used in the drive device 5, a rope tensioning device 4 must be used in the entire rope-driven robotic arm. At this time, the four drive motors 502 can be driven simultaneously, i.e., four motors drive in real time, or the above-mentioned four motors can be driven in a time-sharing manner.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tendon-type rope-driven robotic arm, comprising a boom, a lifting device, a rotary joint, a drive device, and a rope, wherein the rotary joint is fixedly connected to the lifting device to form a cross-shaped structure, and a drive device is provided in both booms, characterized in that, The system also includes a pre-tensioning device. The rotating joint includes two rotating shafts, which are offset on both sides of the middle portion of the lifting device in a direction perpendicular to the lifting device. One end of each of the two booms is connected to one of the two rotating shafts. Each of the two drive devices includes two sets of drive motors. The four sets of drive motors are used to simultaneously drive the rope transmission and cause the rotating joint and the two booms to rotate independently. The rope is laid in a completely antagonistic manner between the ends of the two booms away from the lifting device and the two ends of the lifting device. The rope is also connected to the end of the lifting device through a pre-tensioning device, which includes a fixing plate and a rope clamp. The system includes a rope clamping plate that can move relative to a fixed plate and is fixedly connected to the rope. The rotating joint is also equipped with a guide wheel adapted to the rope. It also includes a rope tensioning device, which is fixedly installed inside the boom. The rope tensioning device includes a U-shaped bracket, a movable bracket, a pulley, and a spring. The U-shaped bracket is fixedly installed inside the boom, and the horizontal end of the U-shaped bracket is slidably connected to the movable bracket. The movable bracket is also elastically connected to the vertical section of the U-shaped bracket via a spring. The movable bracket is equipped with a pulley. A driving device is used to drive the rope transmission and cause the rotating joint and the two booms to rotate.

2. The tendon-type cable-driven robotic arm according to claim 1, characterized in that, The lifting device includes a side plate, a horizontal plate, a vertical plate, a rotating shaft, and a tension gauge. One of the horizontal plates is fixedly connected to another horizontal plate via a vertical plate. A side plate is fixedly connected to the vertical plate. The free end of the side plate is rotatably connected to the rotating shaft. The tension gauge is connected to the rope via the rotating shaft.

3. The tendon-type cable-driven robotic arm according to claim 2, characterized in that, The fixing plate includes a pre-tightening rotating plate, one end of which is fixedly connected to a tension gauge, and the other end is threadedly connected to a pre-tightening screw, which is fixedly connected to a rope clamping plate.

4. The tendon-type cable-driven robotic arm according to claim 3, characterized in that, The rope clamping plate includes a pressure plate and a perforated plate. The perforated plate has at least one perforation adapted to the rope, through which the rope passes. The pressure plate is fixedly connected to the perforated plate by bolts.

5. A tendon-type cable-driven robotic arm according to claim 3, characterized in that, The end of the pre-tightening rotating plate connected to the tension gauge is also fixedly connected to a fixed optical axis, and the pre-tightening rotating plate is connected and fastened to the tension gauge through the fixed optical axis.

6. A tendon-type cable-driven robotic arm according to claim 1, characterized in that, The driving device includes a driving bracket, a driving motor, and a drum. The driving bracket is fixedly connected inside the arm. The top and bottom of the driving bracket are respectively fixedly connected to the driving motor. The output end of the driving motor is connected to the drum, and the drum is connected to the rope.

7. A tendon-type cable-driven robotic arm according to claim 5, characterized in that, The free end of the vertical plate is fixedly connected to a bearing seat, and the bearing seat is rotatably engaged with the rotating shaft.

8. A tendon-type cable-driven robotic arm according to claim 1, characterized in that, The boom is formed by splicing together a truss or frame structure.

9. A tendon-type cable-driven robotic arm according to claim 6, characterized in that, It also includes a pulley system, which includes two first pulleys and a second pulley. Both the first pulley and the second pulley are rotatably connected inside the boom and are located on both sides of the rope tensioning device.

10. A tendon-type cable-driven robotic arm according to claim 9, characterized in that, The drum includes a first drum and a second drum. After the rope is wound around the first drum, the fixed end of the rope is connected to the lifting device through a pulley, the second drum, and the second pulley.

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