A cable-driven adjustable decoupled redundant robotic arm

Abstract

This invention discloses an adjustable, decoupled, redundant robotic arm driven by flexible cables. The first arm is connected to a base via a first hollow universal joint, and the second to Nth arms are connected to the preceding arm via second to Nth hollow universal joints, respectively. Each of the first to N-1 arms includes a hollow sleeve and two end caps connected to both ends of the hollow sleeve. The Nth arm includes an arm body and a front end cap connected to the front end of the arm body. Each set of flexible driving cables contains several flexible driving cables. The front end of the flexible driving cable in the i-th set is connected to the drive mechanism, and the rear end passes sequentially through the hollow sleeves of the first to i-2 arms, reaches the hollow sleeve of the i-1th arm, and exits through the hollow sleeve of the i-1th arm, connecting to the front end cap of the i-th arm. The drive mechanism independently drives each flexible driving cable, and the drive mechanism drives the first, second, ..., Nth arms through the first, second, ..., Nth sets of flexible driving cable groups. This invention achieves complete decoupling structurally.

Description

Technical Field

[0001] This invention belongs to the field of robotic arm technology, specifically relating to an adjustable decoupled redundant robotic arm driven by a flexible cable. Background Technology

[0002] Cable-driven redundant robotic arms are flexible and capable of obstacle avoidance and multi-objective optimization, and are widely used in aerospace, special processing, nuclear power plant monitoring, medical and disaster relief fields.

[0003] Traditional cable-driven robotic arms suffer from the following main problems: fixed structural dimensions prevent adjustment of the overall position of the robotic arm and the size of the end effector; the lengths of the cables driving the various joints are coupled, failing to achieve complete decoupling. Existing technologies, such as structures that reduce coupling through cable sheaths, only analyze the relationships between various coupling parameters in formula derivations, without achieving structural decoupling. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects and provide an adjustable decoupled redundant robotic arm driven by a flexible cable, which solves the technical problem that traditional flexible cable driven robotic arms cannot achieve decoupling from a structural perspective. This invention achieves complete decoupling from a structural perspective.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A cable-driven, adjustable, decoupled redundant robotic arm, comprising: N One arm, N Hollow universal joint, N Group drive cable assembly and drive mechanism;

[0007] set up N The booms are numbered 1, 2, ... N boom, N The hollow universal joints are numbered 1, 2, ... N Hollow universal joint, N The group-driven flexible cable groups are numbered 1, 2... N Group-driven flexible cable assembly;

[0008] The first boom is connected to the base via a first hollow universal joint, and the second... N The boom passes through the 2nd to 3rd respectively. N The hollow universal joint connects to the front boom;

[0009] No. 1~ N In the -1 boom, each boom includes a hollow sleeve and two end caps respectively connected to both ends of the hollow sleeve, so that from the first boom to the second boom... NThe boom's direction is from front to back; the two end caps are designated as the front end cap and the rear end cap, respectively. N The boom includes a boom body and a front end cap connected to the front end of the boom body;

[0010] Each set of drive cables contains several drive cables. The front end of the drive cable in the first set is connected to the drive mechanism, and the rear end is connected to the front end cap of the first arm. i =2…… N , No. i The front end of the drive cable in the drive cable group is connected to the drive mechanism, and the rear end passes through the first to last drive cable in sequence. i -2 After entering the hollow sleeve of the boom, reach the first i -1 The hollow sleeve inside the boom, and made by the first i -1 The hollow sleeve of the boom extends out and connects to the first... i Front end cap of the boom; N >3;

[0011] The drive mechanism independently drives each drive cable, and the drive mechanism is activated by the 1st, 2nd... N Group-driven flexible cable group drive 1, 2... N Arm movement.

[0012] Furthermore, each set of drive cables contains 3 drive cables;

[0013] The hollow sleeve of the boom has circumferentially distributed oblique holes at its rear end, with the axis of the oblique holes perpendicular to the axis of the hollow sleeve. γ Angle, 0° < γ <90°;

[0014] No. i The three drive cables in the group of drive cables are respectively connected to the first drive cable group at the rear end. i -1 The hollow sleeve of the boom has three oblique holes through which it connects to the first... i The front end cap of the boom; the three oblique holes are evenly distributed at 120° along the axial direction of the hollow sleeve.

[0015] Furthermore, ;

[0016] in, D 孔 It is the diameter of the hollow sleeve. L 孔 It is the distance from the oblique hole to the front end of the hollow sleeve along the axis of the hollow sleeve.

[0017] Furthermore, the first~ N -1 The end cap in the boom is fixedly connected to the hollow sleeve; N The boom body and the front end cap are fixedly connected in the boom, section 1~ N-1 The end cap in the boom and the first N The front end cap structure is the same in the boom;

[0018] The edge of the circular end cap is provided with several positioning grooves evenly distributed around the circumference, and the center of the circular end cap is provided with a through hole;

[0019] No. i The rear ends of the drive cables in the group drive cable assembly pass through the first to last cable in sequence. i -2 The front end cover through holes, the interior of the hollow sleeve, and the rear end cover through holes of each boom are formed by the first... i -1 The front end cap through hole of the boom reaches the first i -1 The hollow sleeve inside the boom is made of the first i -1 The hollow sleeve of the boom passes through the oblique hole and passes through the first... i -1 The rear end cap of the boom is connected to the positioning groove after being set. i The front end cap of the boom has a positioning groove.

[0020] Furthermore, the hollow sleeve of the boom is equipped with an elastic sleeve, and a flexible sleeve is installed in the inclined hole of the hollow sleeve. i -1 The positioning groove of the rear end cover of the boom is consistent with the first i A rigid sleeve is installed between the positioning grooves on the front end cap of the boom; the two ends of the flexible sleeve are respectively connected to the rear end of the elastic sleeve and the front end of the rigid sleeve.

[0021] No. i The rear ends of the drive cables in the group drive cable assembly pass through the first to last cable in sequence. i -2 The elastic sleeve inside the hollow sleeve of the boom, the first i -1 The flexible sleeve and rigid sleeve installed on the hollow sleeve of the boom are then connected to the first... i The front end cap of the boom.

[0022] Furthermore, the end cap includes an annular structure and additional patches;

[0023] The annular structure is fixedly connected to the hollow sleeve, and the positioning groove is located on the edge of the annular structure.

[0024] The additional patch is removably installed on the inner ring of the circular structure via a snap-fit, and a through hole is provided in the center of the additional patch;

[0025] No. 1~ N In the -1 boom, angle sensors for measuring the boom's yaw and pitch angles are installed on the front and rear covers, respectively.

[0026] No. N An angle sensor is installed on the front end cap of the boom. N A robotic arm (actuator) is installed at the rear end of the boom.

[0027] The end cap is connected to the hollow universal joint via a bearing.

[0028] Furthermore, the first N The boom is a telescopic boom;

[0029] No. N The boom body consists of a front boom and an end boom. A front end cap is installed at the front end of the front boom, and the rear end of the front boom is transitionally fitted with the end boom. The rear end of the front boom has a notch, and the end boom has n threaded holes from front to back along the axial direction, where n≥3.

[0030] By using screws to mate the notch with different threaded holes, the first... N Adjustment of boom length.

[0031] Furthermore, the first~ N -1 boom includes n 1 long boom and n Two short booms, n 1+ n 2= N -1, n 2≥1; n 1 ≥ 1; the length of the long boom is greater than that of the short boom;

[0032] n Two short booms are set at n Behind a long boom.

[0033] Furthermore, it also includes the sliding mechanism;

[0034] The slide mechanism includes a guide rail motor and a guide rail;

[0035] The base is mounted on the guide rail;

[0036] The guide rail motor drives the guide rail to move, and the movement of the guide rail drives the base, drive mechanism and... N The entire arm was translated.

[0037] Furthermore, the drive mechanism includes 3 N One unit drive mechanism, 3 N Each unit drive mechanism independently drives 3 N Root-driven flexible cable; base is a ring structure with vertical guide rails, 3 N The individual drive mechanisms are evenly distributed in a circular array on the base;

[0038] Each unit drive mechanism includes a motor, coupling, lead screw, and slider;

[0039] The motor's output shaft is connected to a lead screw via a coupling. A slider is mounted on the lead screw and is fixedly connected to a drive cable. The rotation of the motor's output shaft is converted into the translation of the slider on the lead screw, and the translation of the slider causes the drive cable to be tightened or loosened.

[0040] Compared with the prior art, the present invention has at least one of the following advantages:

[0041] (1) This invention creatively proposes an adjustable, decoupled, redundant robotic arm driven by a flexible cable. By designing a novel arm structure, the driving flexible cable, which does not control the arm, passes through the inside, achieving complete decoupling from a structural perspective. This reduces the complexity of the kinematic model, thereby reducing the complexity of the entire system, decreasing computational load and time, effectively improving control efficiency, ensuring real-time performance, and reducing computational load. The effectiveness and optimization of this invention are proven through theoretical derivation. This robotic arm, driven by a flexible cable, can perform many tasks, such as replacing humans in high-risk work, completing detection and grasping tasks in confined spaces, and capturing debris or performing other tasks in space.

[0042] (2) The present invention is provided with structures such as inclined holes, elastic sleeves, and soft sleeves to effectively guide the drive cable, which helps to reduce the friction of the drive cable and improve the transmission efficiency.

[0043] (3) The present invention improves the end-effector flexibility of the robotic arm by using the feature of unequal arm lengths (long arm at the beginning and short and adjustable arm at the end). This conclusion is proved by both images and calculation results.

[0044] (4) By designing a novel end arm structure, the present invention enables the overall position of the robotic arm and the size of the end arm to be adjustable, thereby increasing the range of motion and end flexibility of the robotic arm. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0046] Figure 2 An exploded view of a boom structure;

[0047] Figure 3 This is a schematic diagram of the structure of the attached patch;

[0048] Figure 4 This is a cross-sectional schematic diagram of the attachment patch and buckle; where (a) shows the attachment patch without pressure; and (b) shows the attachment patch with pressure applied.

[0049] Figure 5The diagram shows the different lengths of the eighth boom; where (a) represents the first length state; (b) represents the second length state; and (c) represents the third length state.

[0050] Figure 6 The diagram shows the principle of the telescopic boom; (a) is the first length state; (b) is the top view of the first length state; (c) is the second length state; (d) is the top view of the second length state; (e) is the third length state; and (f) is the top view of the third length state.

[0051] Figure 7 This is a schematic diagram of the drive mechanism containing a single drive cable.

[0052] Figure 8 This is a schematic diagram of the inaccessible area corresponding to a traditional robotic arm.

[0053] Figure 9 This is a schematic diagram of the inaccessible area corresponding to the robotic arm in this invention.

[0054] Figure 10 A simplified diagram of the drive cable routing in a traditional robotic arm;

[0055] Figure 11 This is a simplified diagram of the drive cable routing in the robotic arm of the present invention;

[0056] Figure 12 A flowchart illustrating the parameter transformations in a traditional robotic arm;

[0057] Figure 13 This is a block diagram showing the parameter conversion in the robotic arm of the present invention;

[0058] Figure 14 This is a schematic diagram showing the connection between the drive cable and the end cap of the present invention;

[0059] In the diagram, 1-robotic arm body structure, 2-drive mechanism, 3-slide table mechanism;

[0060] 1-1-Long boom I, 1-2-Long boom II, 1-3-Long boom III, 1-4-Long boom IV, 1-5-Long boom V, 1-6-Short boom I, 1-7-Short boom II, 1-8-Telescopic boom, 1-9-Hollow universal joint I, 1-10-Hollow universal joint II, 1-11-Hollow universal joint III, 1-12-Hollow universal joint IV, 1-13-Hollow universal joint V, 1-14-Hollow universal joint Section VI, 1-15-Hollow Universal Joint VII, 1-16-Hollow Universal Joint VIII, 1-17-Camera, 1-18-Light Source, 1-19-Robot Arm; 2-27-Elastic Sleeve, 2-2-5-Drive Cable II, 2-10-5-Drive Cable X, 2-18-5-Drive Cable XVIII, 2-18-6-Soft Sleeve XVIII, 2-18-7-Rigid Sleeve XVIII, 2-18-8- Flexible cable end XVIII, 2-2-6-Soft sleeve II, 2-2-7-Rigid sleeve II, 2-2-8-Flexible cable end II, 2-10-5-Drive flexible cable X, 2-10-6-Soft sleeve X, 2-10-7-Rigid sleeve X, 2-10-8-Flexible cable end X, 1-8-1-Front section boom, 1-8-2-Retractable boom end cap, 1-8-3-End boom, 1-8-4-Notch, 1-8- 5-End hole, 1-8-6-Angle sensor I', 1-8-7-Angle sensor II', 2-8-5-Drive flexible cable VIII, 2-16-5-Drive flexible cable XVI, 2-24-5-Drive flexible cable XXIV, 1-8-5-1-First end hole, 1-8-5-2-Second end hole, 1-8-5-3-Third end hole, 1-8-4-Notch, 2-25-Base I, 2-26-Base II;

[0061] 1-6-1-Hollow sleeve of short arm rod I1-6, 1-7-1-Hollow sleeve of short arm rod II1-7, 1-1-1-Hollow sleeve of long arm rod I1-1, 1-1-2-End cap I, 1-1-3-End cap II, 1-1-4-Additional patch I, 1-1-5-Additional patch II, 1-1-6-Angle sensor I, 1-1-7-Angle sensor II, 1-1-8-Angled hole;

[0062] 1-1-4-1-Snap I, 1-1-4-2-Snap II, 1-1-4-3-Snap III, 1-1-4-4-Snap IV, 1-1-4-5-Snap V, 1-1-4-6-Snap VI, 1-1-4-7-Patent Sheet, 1-1-4-8-Patent Hole. Detailed Implementation

[0063] The features and advantages of the present invention will become clearer and more explicit from the following detailed description.

[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0065] This invention proposes a redundant robotic arm with unequal arm lengths driven by flexible cables, allowing for adjustment of the overall position and end-effector dimensions. The novel arm structure enables the non-controlling driving cable to pass internally, achieving complete structural decoupling. The effectiveness of this method is theoretically proven through formula derivation. The robotic arm structure of this invention features excellent motion flexibility, obstacle avoidance capabilities, avoidance of robotic arm peculiarities, diverse motion modes, and the ability to achieve multi-objective optimization. In the aerospace field, this structure can be applied to space debris capture, satellite rescue, and space station maintenance; in nuclear power plant monitoring, nuclear industry work, and tunnel boring machine operations, it can replace humans in hazardous working environments for detection and cutting operations; in the civilian field, it can be applied to assembly in confined and harsh environments, special processing work, medical and disaster relief, performing tasks such as detection, processing, and end-effector grasping.

[0066] The robotic arm of the present invention comprises three main parts: the robotic arm body structure 1, the drive mechanism 2, and the slide mechanism 3.

[0067] The robotic arm body structure 1 includes N Each boom has a yaw capability. α i and up and down θ i These two degrees of freedom, plus the overall translational degree of freedom, give the robotic arm a total of 2 N +1 degree of freedom. i The value range is 1~ N , j The value range is 1~ i -1, i, j Indicates the first i, j Each boom has a total of 3 drive motors and 3 drive cables. N .

[0068] The following text will be based on N Taking 8 as an example, combined with the appendix Figures 1-14 Please provide a detailed explanation.

[0069] like Figure 1 As shown, the robotic arm body structure 1 includes N - One boom of unequal length, one boom of adjustable length, N Hollow universal joint, camera 1-17, light source 1-18, robotic arm 1-19.N - One unequal-length boom, consisting of long boom I1-1, long boom II1-2, long boom III1-3, long boom IV1-4, long boom V1-5, short boom I1-6, and short boom II1-7; and one adjustable boom, a telescopic boom 1-8. Long booms I1-1, II1-2, III1-3, IV1-4, and V1-5 are identical in size and shape. Short booms I1-6 and II1-7 are identical in size and shape. The total length of the hollow sleeve 1-6-1 of short boom I1-6, the hollow sleeve 1-7-1 of short boom II1-7, and the hollow sleeve 1-1-1 of long boom I1-1 are unequal; all other components are identical in size and shape. N The hollow universal joints are named Hollow Universal Joint I1-9, Hollow Universal Joint II1-10, Hollow Universal Joint III1-11, Hollow Universal Joint IV1-12, Hollow Universal Joint V1-13, Hollow Universal Joint VI1-14, Hollow Universal Joint VII1-15, and Hollow Universal Joint VIII1-16. N All hollow universal joints are identical in size and shape. Long boom I1-1 is connected to base I2-25 via hollow universal joint I1-9, and long boom I1-1 is connected to long boom II1-2 via hollow universal joint II1-10. Adjacent booms are also connected via hollow universal joints, providing two rotational degrees of freedom: pitch and yaw.

[0070] like Figure 2 As shown, the long arm I1-1 includes a hollow sleeve 1-1-1, end caps I1-1-2 and II1-1-3, additional patches I1-1-4 and II1-1-5, angle sensors I1-1-6 and II1-1-7, oblique holes 1-1-8, bearings, screws, and other connecting parts. End caps I1-1-2 and II1-1-3 are identical, as are angle sensors I1-1-6 and II1-1-7. Angle sensors I1-1-6 and II1-1-7 measure the yaw and pitch angles of the arm, respectively. The position and attitude of the robotic arm can be analyzed using this angle data. Figure 3As shown, the additional patch I1-1-4 includes clips I1-1-4-1, II1-1-4-2, III1-1-4-3, IV1-1-4-4, V1-1-4-5, VI1-1-4-6, a patch sheet 1-1-4-7, and patch holes 1-1-4-8. Additional patches II1-1-5 and I1-1-4 have the same shape, size, and composition. One end of the hollow sleeve 1-1-1 of the long arm I1-1 is provided with an oblique hole 1-1-8. The oblique hole 1-1-8 consists of holes evenly distributed in a ring around the axis. Each hollow sleeve has at least 3 oblique holes; for ease of manufacturing, it is preferable to set all hollow sleeves to have 3 oblique holes. N For different hollow sleeves, only three corresponding oblique holes need to be selected. This design also facilitates the adjustment of the drive cable position layout. By analyzing the force, different drive cable positions can be set. The axis of oblique hole 1-1-8 forms a certain angle with the axis of hollow sleeve 1-1-1. This angle is neither 0 degrees nor 90 degrees. The specific size of this angle is related to factors such as the boom length, and its size should be equal to... Figure 11 The marked γ The angle is calculated using the following formula:

[0071]

[0072] In the formula, D 孔 It is the diameter of the circle formed by the uniformly distributed oblique holes along the axis, that is, the diameter of the hollow sleeve. L 孔 This refers to the distance from the oblique hole to the other end of the hollow sleeve. The oblique holes through which the three drive cables driving the same boom pass are evenly distributed at 120° angles along the axis of the hollow sleeve. When the lengths of the three drive cables change, the angle of the corresponding drive boom also changes. The oblique holes in this invention facilitate decoupling; the inclination angle of the oblique holes is designed according to the shape and dimensions of the boom. γ This helps reduce friction between the drive cable and the boom.

[0073] The additional patch I1-1-4 is connected to the annular structure of the end cap I1-1-2 via six clips (clips I1-1-4-1, ..., clips VI1-1-4-6). For example... Figure 4As shown, pressing the inner ends of the six clips (taking clips I1-1-4-2 and I1-1-4-5 as examples in the diagram) causes the distal ends of the six clips to bend upwards, allowing the additional patch I1-1-4 to be installed onto the annular structure of the end cap I1-1-2. Releasing the pressing force allows the additional patch I1-1-4 and the annular structure of the end cap I1-1-2 to be fixedly connected. The clips are Z-shaped, and when the additional patch I1-1-4 and the annular structure of the end cap I1-1-2 are fixedly connected, the edge of the clip is engaged with the inner ring of the annular structure. Similarly, applying pressure to the inner ends of the six clips allows the additional patch I1-1-4 to be removed from the end cap I1-1-2. Quick installation and removal are achieved through the clips. The elastic sleeve 2-27 passes through the patch hole 1-1-4-8 (i.e., the through hole) and the hollow sleeve 1-1-1, wrapping the drive cable of the rear arm in the middle. Angle sensor I1-1-6 is fixed to end cap I1-1-2 with screws. The connection method of end cap II1-1-3, patch II1-1-5, and angle sensor II1-1-7 is the same as that of end cap I1-1-2, patch I1-1-4, and angle sensor I1-1-6. End cap I1-1-2 is fixed to hollow sleeve 1-1-1 with screws; end cap II1-1-3 is fixed to hollow sleeve 1-1-1 with screws. End cap I1-1-2 is connected to hollow universal joint I1-9 via two bearings, allowing for one rotational degree of freedom between them; end cap II1-1-3 is connected to hollow universal joint II1-10 via two bearings, also having one rotational degree of freedom. The connection methods for long arm links II1-2, III1-3, IV1-4, V1-5, I1-6, and II1-7 are the same as those described above. Setting the lengths of the last three arms of the robotic arm to two short arms and one adjustable arm increases the flexibility of the robotic arm. This will be discussed later in this invention. Figure 8 and Figure 9 It was explained in detail.

[0074] The three drive cables of the drive boom II1-2 are: drive cable II2-2-5, drive cable X2-10-5, and drive cable XVIII2-18-5. Drive cable XVIII2-18-5 passes through the flexible sleeve XVIII2-18-6, which is fixedly connected to the outside of drive cable XVIII2-18-5 by rubber bands at both ends, reducing wear on drive cable XVIII2-18-5. The flexible sleeve XVIII2-18-6 is inserted into the oblique hole 1-1-8, allowing drive cable XVIII2-18-5 to exit from the hollow sleeve 1-1-1 and the elastic sleeve 2-27. Drive cable XVIII2-18-5 passes through the middle of the rigid sleeve XVIII2-18-7, forming a sliding connection. The rigid sleeve XVIII2-18-7 is fixedly connected to the end cap II1-1-3 via a clamp. The end of the drive cable XVIII2-18-5, namely the cable end XVIII2-18-8, is slidably connected to the end cap I1-2-2. The connection method between the drive cable II2-2-5, the flexible sleeve II2-2-6, the rigid sleeve II2-2-7, the cable end II2-2-8, the end cap II1-1-3, the end cap I1-2-2, and the oblique hole 1-1-8 is the same as the connection method described above. The connection method between the drive cable X2-10-5, the flexible sleeve X2-10-6, the rigid sleeve X2-10-7, the cable end X2-10-8, the end cap II1-1-3, the end cap I1-2-2, and the oblique hole 1-1-8 is the same as the connection method described above. The oblique holes through which the drive cables II2-2-5, X2-10-5, and XVIII2-18-5 pass are evenly distributed at 120° angles along the axis of the hollow sleeve 1-1-1. When the lengths of drive cables II2-2-5, X2-10-5, and XVIII2-18-5 change, the angle of the long boom II1-2 also changes accordingly. The connection method of the ends of the remaining drive cables is the same as that of the three drive cables mentioned above. The use of flexible sleeves, rigid sleeves, and elastic sleeves helps reduce wear on the drive cables and boom, thus improving the service life of the drive cables.

[0075] like Figure 5 As shown, the telescopic boom 1-8 includes a front boom 1-8-1, a telescopic boom end cap 1-8-2, an end boom 1-8-3, a notch 1-8-4, and an end hole 1-8-5 (the end hole 1-8-5 includes three holes: the first end hole 1-8-5-1, the second end hole 1-8-5-2, and the third end hole 1-8-5-3). The telescopic boom 1-8 also includes an angle sensor I'1-8-6, bearings, screws, and other connecting parts. The three figures in the diagram illustrate three different lengths of the telescopic boom 1-8.

[0076] The telescopic boom end cap 1-8-2 (i.e., the front end cap of the telescopic boom) is fixedly connected to the front boom 1-8-1 with screws. The telescopic boom end cap 1-8-2 is connected to the hollow universal joint VIII1-16 via two bearings, having one degree of rotational freedom, allowing the telescopic boom 1-8 to connect with the short boom II1-7. Angle sensors I'1-8-6 and II'1-7-7 are fixedly mounted on the telescopic boom end cap 1-8-2 and the rear end cap of the front boom, respectively. The camera 1-17, light source 1-18, and robotic arm 1-19 are all fixedly mounted on the end boom 1-8-3. The three drive cables used to drive the telescopic boom 1-8 are drive cable VIII2-8-5, drive cable XVI2-16-5, and drive cable XXIV2-24-5. The connection methods of drive cables VIII2-8-5, drive cable XVI2-16-5, and drive cable XXIV2-24-5 with the short boom II1-7 and telescopic boom 1-8 are the same as the connection methods of drive cables II2-2-5, drive cable X2-10-5, and drive cable XVIII2-18-5 with the long boom I1-1 and long boom II1-2.

[0077] like Figure 6 As shown, the outer diameter of the end arm 1-8-3 is equal to the inner diameter of the front arm 1-8-1, and the two are in a transition fit with sliding freedom. The end arm 1-8-3 has three threaded holes of the same size: the first end hole 1-8-5-1, the second end hole 1-8-5-2, and the third end hole 1-8-5-3. The notch 1-8-4 of the front arm 1-8-1 is an incomplete circular hole that exceeds a semicircle. Incomplete circular holes are easier to manufacture than round holes, and by making it slightly larger than a semicircle, the overlapping area between the two cylinders (front arm 1-8-1 and end arm 1-8-3) can be minimized while still achieving the connection, thus maximizing efficiency. Align the notch 1-8-4 with the threaded hole of the first end hole 1-8-5-1 and fix it with screws, so that the end arm is in the first length state; align the notch 1-8-4 with the threaded hole of the second end hole 1-8-5-2 and fix it with screws, so that the end arm is in the second length state; align the notch 1-8-4 with the threaded hole of the third end hole 1-8-5-3 and fix it with screws, so that the end arm is in the third length state.

[0078] Drive mechanism 2 is mounted on bases I2-25 and II2-26, which are slidably mounted on slide mechanism 1. Drive mechanism 2 comprises 24 unit drive mechanisms. w Each unit drive mechanism ( wTaking (e.g., 1, 2, ..., 24, each unit driving mechanism drives one driving cable) as an example, the transmission principle of the structure of this invention is described, such as... Figure 7 As shown, the first w Each unit drive mechanism includes motor I2- w -1. Coupling I2- w -2. Lead Screw I2- w -3. Slider I2- w -4. Drive cable I2- w -5. Soft sheath I2- w -6. Rigid Sleeve I2- w -7. I2 at the end of the flexible cord- w -8. Caliper I2- w -9. Other unit drive mechanisms and the first w Each unit has the same drive mechanism.

[0079] Motor I2- w -1 is fixed to the base I2-25 with screws, motor I2- w -1 rotating shaft and coupling I2- w -2 phases connected, motor I2- w -1 can drive coupling I2- w -2 performs rotational motion. Coupling I2- w -2 and lead screw I2- w -3 phase connection, coupling I2- w -2 can drive the lead screw I2- w -3 performs rotational motion. Lead screw I2- w -3 passes through the hole in base II2-26 via the bearing. Slider I2- w -4 and lead screw I2- w -3 phases are connected, and there is one rotational degree of freedom between them. Caliper I2- w -9 is fixed to the base II2-26, slider I2- w -4 and Caliper I2- w There is a translational degree of freedom between -9 and caliper I2- w -9 is used to fix the slider I2- w -4, adjust lead screw I2- w The rotational motion of -3 is converted into a fixed slider I2- w A translational motion of -4. Slider I2- w -4 bottom end and drive cable I2- w -5 is fixedly connected at one end, when the driving flexible cable I2- w When -5 is in the taut state, slider I2- w A translation of -4 can drive the flexible cable I2- w -5 Perform a tensioning motion. Soft sheath I2-w -6. Rigid Sleeve I2- w -7 nested within the drive cable I2- w -5, such as Figure 14 The end of the flexible cord I2- w -8 is set in the drive cable I2- w -5 at the other end, the flexible cord end I2- w The diameter of the -8 is larger than the diameter of the flexible cable body. A rigid cylindrical sleeve is fitted over the outside of the flexible cable body and prevents it from falling off due to the blocking effect at the end of the flexible cable. The rigid cylindrical sleeve is embedded in the groove on the edge of the end cap. The flexible cable body can slide relative to the cylindrical sleeve, and the end of the flexible cable prevents the drive cable from coming out of the groove on the edge of the end cap. Motor I2- w -1 drives the lead screw I2- w -3 Rotate to control slider I2- w -4 moves back and forth, thereby pulling the drive cable I2- w -5 generates displacement, and each group of unit drive mechanisms controls one drive cable. The connection method of other unit drive mechanisms is the same as that of the unit drive mechanisms mentioned above. The 24 groups of unit drive mechanisms, which are the same number as the number of drive cables, are evenly distributed in a circular array in bases I2-25 and II2-26.

[0080] The slide mechanism 3 includes a guide rail 3-1 and a guide rail motor 3-2. The guide rail motor 3-2 drives the guide rail 3-1 to move by rotating, thereby driving the robotic arm body structure 1 and the drive mechanism 2 to translate as a whole.

[0081] In traditional structures, each arm is of equal length, and the corresponding end effector range of motion is as follows: Figure 8 As shown. This invention proposes a robotic arm body structure with unequal arm lengths, comprising five long arms: long arm I1-1, long arm II1-2, long arm III1-3, long arm IV1-4, and long arm V1-5; two short arms: short arm I1-6 and short arm II1-7; and one telescopic arm 1-8. When the length of the telescopic arm 1-8 is one of the specified lengths, the corresponding end effector range of motion is as follows. Figure 9 As shown. Wherein, the boom length... L i Maximum deflection angle (max) ψ i (and minimum turning diameter) D min The relationship between them is shown in the following formula:

[0082] (1)

[0083] by Figure 8 and Figure 9For example, the total length of a traditional robotic arm is the same as that of the robotic arm in this invention, both being 3128mm, and the maximum deflection angle between adjacent arms is 40°, i.e., the first... i The first boom and the first i +1 Maximum deflection angle between booms (max) ψ i All angles are 40°. The lengths of the eight arms in a traditional robotic arm are... L i The diameters are equal, both being 391 mm. The corresponding minimum turning diameter can be obtained using formula (1). D min The length is 1142mm; the length of the eight arms in the robotic arm of this invention is... L i The diameters are respectively set as: 486mm, 486mm, 486mm, 486mm, 206mm, 206mm, and 286mm. The flexibility of the last three joints of the robotic arm in this invention is greatly improved. The minimum turning diameter is obtained using formula (1). D min It is only 602mm.

[0084] like Figure 8 and Figure 9 As shown in the two figures, when the robotic arm penetrates into a narrow space, due to the limitations of obstacles, there is a certain range where the end effector of the robotic arm cannot reach. The inaccessible range of the robotic arm in this invention is significantly less than that of a traditional robotic arm, which also confirms the flexibility of the end joint of the robotic arm in this invention.

[0085] To control a quasi-continuous robotic arm model using 24 drive cables, it is necessary to analyze the transformation relationships between various parameters and establish a kinematic model. In traditional structures, three drive cables control two rotational degrees of freedom of one arm, while the total length of the remaining drive cables is affected by the deflection angle of the initial arm segment, resulting in coupling phenomena. To address the interference between each drive cable and each joint deflection angle, this invention designs a novel cable-driven adjustable decoupled redundant robotic arm. The following theoretical derivation demonstrates that this structure is superior to other structures.

[0086] A simplified diagram illustrating the use of a flexible cable in a traditional robotic arm is shown below. Figure 10 As shown in the figure, the lengths of the two drive cables A and B in the drive arm III1-3 are related not only to the deflection angle of the hollow universal joint III1-11, but also to the angle of the hollow universal joint II1-10. That is, in traditional robotic arms, the length of the drive cables is coupled with the angles of the various joints passed through. A simplified diagram of the drive cable routing in the robotic arm of this invention is shown below. Figure 11As shown in the figure, the drive cables A and B of the drive arm III1-3, with the help of the additional patch, pass through the center of the hollow universal joint II1-10. Therefore, the lengths of these two drive cables are independent of the deflection angle of the hollow universal joint II1-10. The drive cables A and B of the drive arm III1-3 pass through the center of joint 3, and their lengths are related to the deflection angle of the hollow universal joint III1-11. That is, in the robotic arm of this invention, the length of the drive cables is only related to the angle at the joint in front of the drive arm, and has no coupling effect with the angles of other joints.

[0087] The traditional cascaded structure of a cable-driven redundant robotic arm has relatively complex kinematic analysis and exhibits certain coupling relationships. This coupling phenomenon is particularly pronounced when mapping between joint space and drive space. The following invention uses a... N Taking a robotic arm with 8 levers as an example, let's analyze the flexible cable drive space ( l ja , l jb , l jc ), joint space ( α i , θ i The parameter conversion relationship between () and (). (where) l ja , l jb , l jc To drive the first j The lengths of the three drive cables of each boom, α i , θ i For the first i The angle at each joint, in other words α i It is the first i The yaw angle of each boom relative to the previous boom θ i It is the first i The pitch angle of each boom relative to the previous boom.

[0088] Control the first j The total length of the three drive cables of the boom at and after the first joint is as follows: l ja , l jb , l jc The calculation formula is as follows:

[0089] (2)

[0090] In the formula, l ija , l ijb , l ijc It is the third control j The drive cable of the first boom is in the... i The length at each joint L i It is the first i The length of each boom arm d It is the distance from the center point of the joint to the end face of the arm. L i and d This is known data.

[0091] The length of the drive cable at a joint ( l ija , l ijb , l ijc ) and joint angle ( α i , θ i The mapping relationship between them is as follows:

[0092] (3)

[0093] In the formula, s is sin; c is cos; r It is the distance between the center of the hole through which the driving cable passes and the center of the boom. α i , θ i Given the known circumstances, substitute the control number... j The position and angle of the first drive cable of the boom φ A obtained l That is l ija Similarly, substituting the control... j The position and angle of the second drive cable of the boom φ B It can be obtained l ijb Similarly, substituting the control... j The position and angle of the third drive cable of the boom φ C It can be obtained l ijc .

[0094] Based on formulas (2) and (3), the parameter transformation diagrams in a traditional robotic arm can be derived, where the mapping relationship between the joint deflection angle and the length of the drive cable is as follows: Figure 12 As shown in the figure. It can be seen from the figure that it is necessary to know... α 1. θ 1. α 2. θ 2, ... α 8. θ 8. These 2 × 8 = 16 parameters, calculate... l 18a , l 18b , l 18c , l 28a , l 28b , l 28c ... l 88a , l 88b , l 88c These 3N data points, when summed, are needed to calculate the total length of the three drive cables that power the 8th boom. l 8a , l 8b , l 8c In summary, multiple sets of data need to be calculated at each joint, and then summed together to obtain the real-time data for the overall length of the drive cable. Determining the drive cable length through joint deflection angles requires calculating a certain number of data sets. N 0 as follows:

[0095]

[0096] Even if the length of the driving cable is known, calculating the deflection angles of each joint requires a significant amount of computation. The first step is based on... l 1a , l 1b , l 1c Seeking l 11a , l 11b , l 11c Then through l 11a , l 11b , l 11c Solving the constructed overdetermined equationsα 1. θ 1. The second step is to... α 1. θ 1. Calculate the length of the driving cable at the first joint. l 12a , l 12b , l 12c , l 13a , l 13b , l 13c ... l 18a , l 18b , l 18c Then solve l 22a , l 22b , l 22c The solution formula is as follows:

[0097]

[0098] Then through l 22a , l 22b , l 22c Solving the constructed overdetermined equations α 2. θ 2. By analogy, all of them can be found. α i , θ i Size.

[0099] In summary, in the traditional cable-driven / flexible cable-driven robotic arm structure, the following can be utilized: α i , θ i Derivation l ia , l ib , l ic It can also be used l ia , l ib , l ic Derivation α i , θ iHowever, there is a coupling phenomenon in the calculation of forward and inverse kinematics, resulting in a large amount of computation.

[0100] Next, we analyze the parameter conversion diagram of the robotic arm of this invention. The length of the driving cable at the joint of the arm can be calculated by formula (3). The driving cables of the other arms pass through the center of the arm and the center of the joint. r The length of the flexible cord at this joint is always close to zero, therefore it is always 2. d It is unaffected by the joint angle. Therefore, we can obtain... Figure 13 The diagram illustrates the mapping relationship between the joint deflection angle and the length of the drive cable. (Controlling the...) j The total lengths of the three drive cables of the boom after the first joint are as follows: l ja , l jb , l jc The calculation formula is as follows:

[0101] (4)

[0102] In the formula, l jja , l jjb , l jjc It is the third control j The drive cable of the first boom is in the... j The length at each joint L i It is the first i The length of each boom arm d It is the distance from the center point of the joint to the end face of the arm. L i and d This is known data.

[0103] from Figure 13 As can be seen from formula (4), it is only necessary to know α 8. θ With these two parameters, the total length of the three drive cables driving the eighth boom can be calculated. l 8a , l 8b , l 8c In this invention, only three sets of data need to be calculated at each joint, and then summed together to obtain the real-time data of the total length of the drive cable. The number of data points to be calculated is [not specified]. N 1. As follows:

[0104]

[0105] If the length of the driving cable is known, calculating the deflection angles of each joint does not require extensive computation. l 1a , l 1b , l 1c Seeking l 11a , l 11b , l 11c And then find α 1. θ 1; Similarly, according to l 2a , l 2b , l 2c Seeking l 22a , l 22b , l 22c And then find α 2. θ 2. In summary, through l jja , l jjb , l jjc It can be found α i , θ i Other parameters have no effect on it, meaning there is no coupling phenomenon. The novel cable-driven adjustable decoupled redundant manipulator of this invention optimizes the structure, thereby simplifying the kinematic model, not only decoupling the coupling phenomenon but also reducing the computational load of kinematics.

[0106] In summary, in a traditional robotic arm, the lengths of the 3N drive cables are all related to the first joint angle, the lengths of the 3N-3 drive cables are related to the second joint angle, and so on. The final joint angle only affects the lengths of the 3 drive cables. In other words, in a traditional robotic arm, the lengths of the 3 drive cables control the final joint angle, the lengths of the 6 drive cables control the second-to-last joint angle, and the lengths of the 3N drive cables control the first joint angle.

[0107] In the structure of this invention, only the lengths of three flexible cables are related to each joint angle; adjusting the lengths of these three cables is sufficient to control one joint. This invention presents a completely decoupled structure, facilitating the analysis of the mapping relationships between various parameters and simplifying control. A single joint / arm degree of freedom can be controlled using only three cables.

[0108] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0109] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A cable-driven, adjustable, decoupled redundant robotic arm, characterized in that, include N One arm, N Hollow universal joint, N Group drive cable assembly and drive mechanism; set up N The booms are numbered 1, 2, ... N boom, N The hollow universal joints are numbered 1, 2, ... N Hollow universal joint, N The group-driven flexible cable groups are numbered 1, 2... N Group-driven flexible cable assembly; The first boom is connected to the base via a first hollow universal joint, and the second... N The boom passes through the 2nd to 3rd respectively. N The hollow universal joint connects to the front boom; No. 1~ N In the -1 boom, each boom includes a hollow sleeve and two end caps respectively connected to both ends of the hollow sleeve, so that from the first boom to the second boom... N The boom's direction is from front to back; the two end caps are designated as the front end cap and the rear end cap, respectively. N The boom includes a boom body and a front end cap connected to the front end of the boom body; Each set of drive cables contains several drive cables. The front end of the drive cable in the first set of drive cables is connected to the drive mechanism, and the rear end is connected to the front end cover of the first arm. make i =2…… N , No. i The front end of the drive cable in the drive cable group is connected to the drive mechanism, and the rear end passes through the first to last drive cable in sequence. i -2 After entering the hollow sleeve of the boom, reach the first i -1 The hollow sleeve inside the boom, and made by the first i -1 The hollow sleeve of the boom extends out and connects to the first... i Front end cap of the boom; The drive mechanism independently drives each drive cable, and the drive mechanism is activated by the 1st, 2nd... N Group-driven flexible cable group drive 1, 2... N Arm movement; Each set of drive cables contains 3 drive cables; The hollow sleeve of the boom has circumferentially distributed oblique holes at its rear end, with the axis of the oblique holes perpendicular to the axis of the hollow sleeve. γ Angle, 0° < γ <90°; No. i The three drive cables in the group of drive cables are respectively connected to the first drive cable group at the rear end. i -1 The hollow sleeve of the boom has three oblique holes through which it connects to the first... i The front end cap of the boom; the three oblique holes are evenly distributed at 120° along the axial direction of the hollow sleeve; The hollow sleeve of the boom has an internal elastic sleeve, and a flexible sleeve is installed in the inclined hole of the hollow sleeve. i -1 The positioning groove of the rear end cover of the boom is consistent with the first i A rigid sleeve is installed between the positioning grooves on the front end cap of the boom; the two ends of the flexible sleeve are respectively connected to the rear end of the elastic sleeve and the front end of the rigid sleeve. No. i The rear ends of the drive cables in the group drive cable assembly pass through the first to last cable in sequence. i -2 The elastic sleeve inside the hollow sleeve of the boom, the first i -1 The flexible sleeve and rigid sleeve installed on the hollow sleeve of the boom are then connected to the first... i Front end cap of the boom; No. N The boom is a telescopic boom; No. N The boom body consists of a front boom and an end boom. A front end cap is installed at the front end of the front boom, and the rear end of the front boom is transitionally fitted with the end boom. The rear end of the front boom has a notch, and the end boom has n threaded holes from front to back along the axial direction, where n≥3. By using screws to mate the notch with different threaded holes, the first... N Adjustment of boom length; No. 1~ N -1 boom includes n 1 long boom and n Two short booms, n 1+ n 2= N -1, n 2≥1; The length of the long boom is greater than that of the short boom; n Two short booms are set at n Behind a long boom.

2. The adjustable decoupled redundant robotic arm driven by a flexible cable according to claim 1, characterized in that, ； in, D 孔 It is the diameter of the hollow sleeve. L 孔 It is the distance from the oblique hole to the front end of the hollow sleeve along the axis of the hollow sleeve.

3. The adjustable decoupled redundant robotic arm driven by a flexible cable according to claim 1, characterized in that, No. 1~ N -1 The end cap in the boom is fixedly connected to the hollow sleeve; N The boom body and the front end cap are fixedly connected in the boom, section 1~ N -1 The end cap in the boom and the first N The front end cap structure is the same in the boom; The edge of the circular end cap is provided with several positioning grooves evenly distributed around the circumference, and the center of the circular end cap is provided with a through hole; No. i The rear ends of the drive cables in the group drive cable assembly pass through the first to last cable in sequence. i -2 The front end cover through holes, the interior of the hollow sleeve, and the rear end cover through holes of each boom are formed by the first... i -1 The front end cap through hole of the boom reaches the first i -1 The hollow sleeve inside the boom is made of the first i -1 The hollow sleeve of the boom passes through the oblique hole and passes through the first... i -1 The rear end cap of the boom is connected to the positioning groove after being set. i The front end cap of the boom has a positioning groove.

4. The adjustable decoupled redundant robotic arm driven by a flexible cable according to claim 3, characterized in that, The end cap includes a ring-shaped structure and an additional patch; The annular structure is fixedly connected to the hollow sleeve, and the positioning groove is located on the edge of the annular structure. The additional patch is removably installed on the inner ring of the circular structure via a snap-fit, and a through hole is provided in the center of the additional patch; No. 1~ N In the -1 boom, angle sensors for measuring the boom's yaw and pitch angles are installed on the front and rear covers, respectively. No. N An angle sensor is installed on the front end cap of the boom. N A robotic arm is installed at the rear end of the boom; The end cap is connected to the hollow universal joint via a bearing.

5. The adjustable decoupled redundant robotic arm driven by a flexible cable according to claim 1, characterized in that, It also includes the slide mechanism; The slide mechanism includes a guide rail motor and a guide rail; The base is mounted on the guide rail; The guide rail motor drives the guide rail to move, and the movement of the guide rail drives the base, drive mechanism and... N The entire arm was translated.

6. The adjustable decoupled redundant robotic arm driven by a flexible cable according to claim 5, characterized in that, The drive mechanism includes 3 N One unit drive mechanism, 3 N Each unit drive mechanism independently drives 3 N Root-driven flexible cable; base is a ring structure with vertical guide rails, 3 N The individual drive mechanisms are evenly distributed in a circular array on the base; Each unit drive mechanism includes a motor, coupling, lead screw, and slider; The motor's output shaft is connected to a lead screw via a coupling. A slider is mounted on the lead screw and is fixedly connected to a drive cable. The rotation of the motor's output shaft is converted into the translation of the slider on the lead screw, and the translation of the slider causes the drive cable to be tightened or loosened.

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