A cable-pulling parallel robot multi-modal fusion positioning device and positioning method

Abstract

The application discloses a kind of cable traction parallel robot multimodal fusion positioning device and positioning method, including fixed on cable traction parallel robot system outlet point servo mechanism and traction cable fixed pulley mechanism traction cable left and right swing when servo;Traction cable is passed through the traction cable fixed pulley mechanism of traction cable fixed pulley mechanism pulley;For passing through the axis rotation laser ranging sensor servo measurement mechanism around integral pulley when traction cable swings up and down;Real-time measurement of traction cable movement speed, the included angle of traction cable and vertical shaft, the sensing measurement device of the distance between traction cable and reflection plate from outlet point;And the reflection plate device of receiving laser emitted by laser ranging sensor, indirectly measure the length of traction cable.The application directly measures the position of terminal motion platform anchor point in space, deduces the pose of terminal motion platform in space, realizes high-frequency robot terminal motion platform high-speed high-precision fusion positioning.

Description

Technical Field

[0001] This invention relates to cable-driven parallel robots, specifically to a two-dimensional planar reconfigurable cable-driven parallel robot multimodal fusion positioning device and positioning method. Background Technology

[0002] Cable-driven parallel robots are a unique and advanced robotic system. Their core lies in the use of a cable-driven parallel mechanism, a design that enables complex motion control and manipulation tasks. Compared to traditional rigid-connected robots, cable-driven parallel robots offer greater degrees of freedom, higher maneuverability, and a wider workspace. The robot consists of multiple cables fixed to a frame, and the drive system precisely controls their length and tension, allowing the robot to achieve flexible and varied movements with high flexibility.

[0003] Cable-driven parallel robots, as a special type of robot structure, rely heavily on the accuracy of their sensors for control precision. This accuracy directly impacts the robot's position control. Insufficient sensor accuracy will result in a deviation between the actual and expected positions of the robot's end effector, thus affecting the robot's operational accuracy.

[0004] In high-speed or complex dynamic environments, cable-driven parallel robots need to respond quickly and accurately to external commands and adjust their own state. This requires sensors to have high sampling rates, low latency, and high stability to ensure real-time and accurate capture of changes in the robot's motion. Poor sensor performance can lead to problems such as lag, jitter, or loss of control during dynamic control, severely impacting the robot's operational efficiency and safety.

[0005] The accuracy of sensor measurements is also closely related to the robot's load distribution and balance control. In cable-driven parallel robots, precise load distribution and balance must be maintained between the various cables and pulleys to ensure the stability and rigidity of the overall robot structure. If the sensors cannot accurately measure the tension of the cables or the positional changes of the pulleys, the load distribution and balance control will be affected, potentially leading to robot structural deformation, vibration, or failure.

[0006] Existing methods for locating the end effector platform of cable-driven parallel robots mainly include: 1) Using encoders to measure the rotational motion of motors to indirectly measure the displacement of the traction cable, and solving the pose of the end effector platform through forward kinematics equations. The displacement of the traction cable measured by this method is an approximate displacement, ignoring the cable displacement caused by the change of wrap angle at the exit pulley and interference from the environment. The measured cable length is inaccurate, and the forward kinematics iterative optimization requires a lot of computing power, making it unsuitable for real-time measurement; 2) Using multiple fixed cameras mounted on the frame to measure the relative positions of marker points on the end effector platform, and measuring the pose of the end effector platform through spatial geometric relationships. Since multiple cameras are used and this method also requires a lot of computing power, it cannot meet the requirements of high-frequency closed-loop control; 3) Traditional measurement platforms are located outside the cable-driven parallel robot system, occupying a large space, easily affected by environmental interference, and cannot be flexibly deployed. Summary of the Invention

[0007] To address the aforementioned deficiencies in the existing technology, the present invention aims to provide a multimodal fusion positioning device and method for cable-driven parallel robots. This method uses laser rangefinders, photoelectric encoders, and angle sensors to measure exit point information. It calculates the position of the end effector platform anchor point in space through two-dimensional spatial geometric relationships, thereby calculating the pose of the end effector platform in space and achieving indirect measurement of the pose of the cable-driven parallel robot.

[0008] The present invention is achieved through the following technical solution.

[0009] One aspect of the present invention provides a multimodal fusion positioning device for a cable-driven parallel robot, comprising:

[0010] The exit point follow-up mechanism is fixed on the cable-traction parallel robot system. When the end motion platform moves, it is used to follow the left and right swing of the traction cable with the fixed pulley mechanism of the traction cable, so that the laser emitted by the laser range sensor remains parallel to the traction cable.

[0011] The traction cable fixed pulley mechanism is used to pass the traction cable over the pulley of the traction cable fixed pulley mechanism, and rotate under the action of the change in the length of the traction cable to realize the change of direction of the traction cable;

[0012] The laser rangefinder sensor follow-up measurement mechanism is configured as a laser rangefinder sensor support frame. The laser rangefinder sensor support frame is used to rotate around the axis of an integrated pulley when the traction cable swings up and down. The traction cable and the laser emitted by the laser rangefinder sensor remain parallel.

[0013] The sensing and measuring device is used to measure in real time the speed of the traction cable, the angle between the traction cable and the vertical axis of the laser rangefinder sensor support frame, and the distance from the exit point of the traction cable fixed pulley mechanism to the reflector.

[0014] A reflector device is mounted on the traction cable at a certain distance from the anchor point of the end motion platform. It is used to receive the laser emitted by the laser rangefinder and indirectly measure the length of the traction cable.

[0015] Preferably, the exit point follow-up mechanism includes a main support, a pin bearing support frame, a follow-up pin, and a pin positioning sleeve. The main support is fixed to the frame of the cable-driven parallel robot system, and the pin bearing support frame is installed above the main support. A deep groove ball bearing is provided on the pin bearing support frame. The follow-up pin is sleeved in the pin bearing support frame, and the pin is fitted with a retaining spring. A pin positioning sleeve is sleeved under the pin bearing support frame.

[0016] Preferably, the traction cable fixed pulley mechanism includes a pulley support frame and an integral pulley mounted on the pulley support frame via a pin. The pulley support frame is a frame structure, with its top connected to the pin positioning sleeve.

[0017] Preferably, the laser ranging sensor follow-up measurement mechanism includes an encoder bearing bracket, an angle sensor bearing bracket, a laser ranging sensor support frame, a laser ranging sensor, and a counterweight. The angle sensor bearing bracket and the encoder bearing bracket are connected side by side to the pulley support frame. The laser ranging sensor support frame is connected to the angle sensor bearing bracket and the encoder bearing bracket via a top rotating arm. A counterweight is connected to each of the pair of rotating arms. The laser ranging sensor is installed at the lower part of the laser ranging sensor support frame.

[0018] Preferably, the rotating arm of the laser rangefinder sensor support frame has a through hole for the traction cable, through which the traction cable passes and connects to the counterweight.

[0019] Preferably, the laser rangefinder sensor support frame has a cable routing hole at the center line of the back, through which the traction cable passes after winding out from the integrated pulley.

[0020] Preferably, the sensing and measuring device includes a photoelectric encoder and an angle sensor, which are respectively fixed on the outside of the encoder bearing bracket and the angle sensor bearing bracket.

[0021] Preferably, the reflector device includes a reflector flange and a reflector, with the reflector fixed to the traction cable and kept perpendicular to the traction cable.

[0022] Another aspect of the present invention provides a positioning method for the multimodal fusion positioning device of the cable-driven parallel robot, comprising:

[0023] The positioning device body is installed at the four corners of the two-dimensional plane of the planar four-cable three-degree-of-freedom cable traction parallel robot system. After the traction cable is led out from the drive device, it is wound around the integrated fixed pulley and passes through the cable routing hole of the laser range sensor support frame, and is fixed at the corresponding anchor point of the end motion platform.

[0024] When the end motion platform swings left and right relative to the positioning device body under the action of the drive device, the follower pin rotates under the action of lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction cable to ensure that the laser emitted by the laser range sensor remains parallel to the traction cable.

[0025] When the end-effector swings up and down relative to the positioning device body, the laser rangefinder support frame rotates around the integrated pulley axis under vertical pressure, ensuring that the laser emitted by the laser rangefinder remains parallel to the traction cable; the angle sensor measures the rotation angle of the laser rangefinder support frame.

[0026] When the traction cable is retracted or extended under the action of the traction cable drive device, the integrated pulley is stationary relative to the traction cable. The photoelectric encoder measures the rotational speed of the integrated pulley, and then measures the length of the traction cable.

[0027] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0028] 1. In this invention, the traction cable is wound on a fixed pulley mechanism. When the drive device controls the end motion platform to move in space, causing the device to swing left and right, the exit point follower mechanism in the device moves accordingly to counteract the axial force of the traction cable on the pulley, thereby ensuring that the exit point parameters remain unchanged and improving the stability of the system operation. When swinging up and down, the laser rangefinder support frame rotates around the integrated pulley axis, so that the laser emitted by the laser rangefinder sensor remains parallel to the traction cable; the rotation angle of the laser rangefinder support frame is accurately obtained.

[0029] 2. The device uses laser rangefinders, photoelectric encoders, and angle sensors to collect real-time information on the length and speed of the traction cable, as well as the angle between the traction cable and the y-axis of the coordinate system. By comprehensively utilizing laser rangefinders, angle sensors, and photoelectric encoders, the device achieves a high sampling frequency, with a maximum combined sampling frequency of 100Hz. This supports closed-loop motion control of cable-driven parallel robots at medium to high speeds, avoiding problems such as robot motion instability, response delay, and decreased control accuracy caused by untimely feedback, thus achieving high-speed and high-precision positioning in the end-effector motion platform.

[0030] 3. While directly measuring the length of the traction cable using a photoelectric encoder, the length of the traction cable is indirectly measured using a combination of a laser rangefinder and a reflector. The simultaneous measurement by the two sensors improves the reliability of the traction cable length measurement value, reduces errors caused by environmental interference, and thus improves the accuracy of robot motion control. It also has low computational load and strong real-time performance.

[0031] 4. The sensors are placed near the exit point to reduce the impact of environmental factors on sensor measurements and improve the stability of system operation.

[0032] 5. Compared with dynamic visual measurement and laser tracking measurement systems, this device integrates the exit point follow-up mechanism, the laser rangefinder follow-up measurement mechanism, the traction cable fixed pulley mechanism, the sensing measurement device, and the reflector device into the cable traction parallel robot system. It has a compact structure, is stable and reliable, and can be deployed flexibly.

[0033] 6. By installing counterweights on the laser sensor support frame, the load on the laser rangefinder support frame and the laser rangefinder on the traction cable is balanced. Furthermore, the use of support frame bearings reduces the torque caused by friction when the laser sensor support frame rotates, thereby reducing the impact of the device on the tension of the traction cable and comprehensively improving the stability and reliability of the device operation.

[0034] 7. By directly measuring the position of the anchor point of the end effector platform in space and combining it with the geometric characteristics of the end effector platform, the pose of the end effector platform in space is indirectly derived through geometric relationships. This avoids the need to use numerical optimization and other methods to solve the forward kinematics of the end effector platform pose, simplifies the measurement process of the operating state of the end effector platform of the cable-driven parallel robot, provides a new end effector pose measurement scheme for cable-driven parallel robots, realizes automatic cable routing at the traction cable exit point, increases the frequency of end effector pose measurement of cable-driven parallel robots, and thus improves the dynamic performance of the robot system. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 This is a schematic diagram of a multimodal fusion positioning device for cable-driven parallel robots.

[0037] Figure 2 This is a schematic diagram of the robot's multimodal localization operation.

[0038] Figure 3 This is a schematic diagram of the exit point follower mechanism;

[0039] Figure 4 This is a schematic diagram of the laser rangefinder sensor's servo measurement mechanism;

[0040] Figure 5 This is a schematic diagram of the traction cable fixed pulley mechanism;

[0041] Figure 6 This is a schematic diagram of a sensing and measuring device;

[0042] Figure 7 This is a schematic diagram of the reflector device;

[0043] Figure 8 This is a schematic diagram of a multimodal fusion positioning device measuring the displacement state of a traction cable;

[0044] Figure 9 This is a schematic diagram of the device anchor point location measurement;

[0045] Figure 10 This is a schematic diagram of robot pose measurement.

[0046] In the diagram: 1-Main support frame, 2-Pin bearing support frame, 3-Follower pin, 4-Pin positioning sleeve, 5-Pulley support frame, 6-Integrated pulley, 7-Angle sensor-bearing bracket, 8-Encoder bearing bracket, 9-Laser rangefinder support frame, 10-Laser rangefinder, 11-Photoelectric encoder, 12-Angle sensor, 13-Reflector flange, 14-Reflector, 15-Counterweight, 16-Traction cable, 17-Bearing, 18-Traction cable drive device, 19-End motion platform. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0048] like Figure 1 , Figure 2 As shown in the figure, an embodiment of the present invention provides a multimodal fusion positioning device for a cable-driven parallel robot, comprising a positioning device body consisting of an exit point follower mechanism, a traction cable pulley mechanism, a laser rangefinder sensor follower measurement mechanism, and a sensing measurement device; the exit point follower mechanism is located at the top of the mechanism, the traction cable pulley mechanism is connected below the exit point follower mechanism, the laser rangefinder sensor follower measurement mechanism is connected to the traction cable pulley mechanism, and the sensing measurement device is installed on both sides of the laser rangefinder sensor follower measurement mechanism; it also includes a reflector device on the traction cable at a certain distance from the end motion platform anchor point, used to receive the laser emitted by the laser rangefinder sensor and indirectly measure the length of the traction cable.

[0049] The positioning device body is fixed at the four corners of the planar four-cable three-degree-of-freedom cable-traction parallel robot system. The traction cable 16 passes around the traction cable pulley mechanism, passes through the hole of the laser rangefinder follow-up measurement mechanism, one end passes through the reflector device and is fixed to the end motion platform 19, and the other end is fixed to the drive device 18. Under the action of the drive device 18, the traction cable moves with the end motion platform 19. The sensor measurement device obtains the distance between the exit point follow-up mechanism and the corresponding anchor point of the end motion platform 19, and calculates the attitude of the end motion platform 19 in space.

[0050] Among them, such as Figure 3As shown, the exit point follower mechanism includes: a main support 1, a pin bearing support frame 2, a follower pin 3, and a pin positioning sleeve 4. The main support 1 is fixed to the frame of the cable-driven parallel robot system, and the pin bearing support frame 2 is mounted on the upper surface of the main support 1. A deep groove ball bearing is installed on the pin bearing support frame 2. The follower pin 3 is fitted inside the inner ring of the pin bearing support frame 2. The pin has grooves at both ends, and a retaining ring is installed at one end of the pin. The end face of the retaining ring contacts the bearing on the upper surface of the pin bearing support frame 2, thereby axially positioning the upper surface bearing. The pin positioning sleeve 4 is fitted on the lower surface bearing of the pin bearing support frame 2. One end of the sleeve contacts the inner ring of the lower surface bearing of the pin bearing support frame 2, achieving axial positioning of the lower surface bearing. The other end of the pin positioning sleeve 4 contacts the upper surface of the pulley support frame 5 of the traction cable pulley mechanism, achieving axial positioning of the pin positioning sleeve. When the end effector platform moves, it follows the traction cable as it swings left and right with the traction cable of the traction cable fixed pulley mechanism.

[0051] The traction cable fixed pulley mechanism includes an integrated pulley 6 and a pulley support frame 5. The pulley support frame 5 is a frame structure, with its top connected to the pin positioning sleeve 4. The integrated pulley 6 is fixed to the pulley support frame 5 by a pin. The pulley support frame 5 has a through hole for easy assembly of the follower pin. The pulley support frame 5 is machined using sheet metal technology and is made of 5053 aluminum alloy. A retaining spring is installed at the slot at the other end of the pin, with the end face of the retaining spring contacting the lower surface of the pulley support frame to achieve axial positioning of the pulley support frame 2. Under the preload generated when the retaining springs are installed at both ends, friction exists between the pulley support frame 5 and the follower pin. When the pulley support frame rotates, the follower pin 3 remains stationary relative to the pulley support frame. It rotates under the action of changes in the length of the traction cable to realize the change of direction of the traction cable.

[0052] like Figure 4 , Figure 5 and Figure 6 As shown, the laser rangefinder sensor follow-up measurement mechanism includes: encoder bearing bracket 8, angle sensor bearing bracket 7, laser rangefinder sensor support frame 9, laser rangefinder sensor 10, and counterweight 15. Two frame-shaped brackets are connected side by side to the pulley support frame 5, namely the angle sensor bearing bracket 7 and the encoder bearing bracket 8. Bearings 17 are coaxially mounted on both sides of the angle sensor bearing bracket 7 and the encoder bearing bracket 8 with the integrated pulley 6.

[0053] like Figure 5 As shown, the inner sides of the left and right ends of the laser rangefinder sensor support frame 9 are designed with a solid stepped shaft and a hollow shaft, respectively. The solid stepped shaft is divided into two steps, with a shoulder between the first and second steps. The end face of the shoulder contacts the inner ring of the bearing on the outer side of the angle sensor-bearing bracket 7, achieving axial positioning of the bearing. The hollow shaft is used to assemble the integrated pulley 6. The end face of the hollow shaft contacts the inner ring of the bearing on the outer side of the encoder-bearing bracket 8, achieving axial positioning of the bearing.

[0054] The laser rangefinder support frame 9 is connected to the angle sensor bearing bracket 7 and the encoder bearing bracket 8 via a top rotating arm, and is coaxially mounted with the integrated pulley 6. A counterweight 15 is connected to each of the pair of rotating arms, and the laser rangefinder sensor 10 is installed at the bottom of the laser rangefinder support frame 9.

[0055] The laser rangefinder sensor support frame 9 has a through hole for the traction cable 16, which passes through the through hole and connects to the counterweight 15. The counterweight 15 is used to counteract the friction caused by the weight of the laser rangefinder sensor support frame 9 and the laser rangefinder sensor 10. The counterweight 15 has two threaded holes, and the lever arms at the left and right ends are balanced.

[0056] like Figure 8 As shown, a cable routing hole is provided at the center line of the back of the laser rangefinder support frame 9. The traction cable 16 passes through the cable routing hole after coming out of the integrated pulley 6. When the traction cable swings up and down around the integrated pulley under the action of the end motion platform 19, the traction cable generates positive pressure on the laser rangefinder support frame 9. Under the action of positive pressure, the laser rangefinder support frame swings up and down with the traction cable.

[0057] The laser rangefinder uses the pulse TOF method to measure distance values, with a maximum sampling frequency of 100Hz.

[0058] During operation, the traction cable of the laser rangefinder sensor's follow-up measuring mechanism passes through the cable routing hole on the laser rangefinder sensor's support frame. When the end platform moves and the traction cable swings up and down, the laser rangefinder sensor's support frame swings up and down under the normal pressure of the traction cable, ensuring that the traction cable remains parallel to the laser emitted by the laser rangefinder sensor. Simultaneously, a counterweight is installed at the tail end of the laser rangefinder sensor's support frame to counteract the torque of the laser rangefinder sensor on its axis, preventing the device from interfering with the traction cable and applying additional cable tension.

[0059] In one embodiment, the integrated pulley is machined using a lathe and features an asymmetrical design with the pulley as the center. The pulley has a "V"-shaped cross-section, with the left end shaft being a three-step long shaft and the right end shaft being a two-step short shaft. The shoulder end face between the first and second steps of the long shaft contacts the inner ring of the encoder-bearing bracket inner bearing, and the shoulder end face between the first and second steps of the short shaft contacts the inner ring of the angle sensor-bearing bracket inner bearing, thus achieving axial positioning of the integrated pulley. The traction cable is led out from the drive device 18 and wound around the "V"-shaped groove of the integrated pulley. When the traction cable moves under the action of the drive device 18, the integrated pulley rotates relative to the drive device 18 under the action of friction.

[0060] like Figure 6As shown, the sensing and measurement device includes a photoelectric encoder 11 and an angle sensor 12. The photoelectric encoder 11 and the angle sensor 12 are respectively fixed to the outside of the encoder bearing bracket 8 and the angle sensor bearing bracket 7.

[0061] The photoelectric encoder frame has threaded through holes for fixing to the encoder bearing bracket 8 with screws and nuts. The encoder code disk axis and side have threaded through holes for fixing to the third step of the integrated pulley's long shaft with set screws. When the integrated pulley rotates under the friction of the traction cable, the encoder code disk remains stationary relative to the pulley. The encoder read head is fixed to the encoder bearing bracket with M2 screws. The reading device reads the relative movement of the code disk. The angle sensor has a hollow shaft at its center. During assembly, the "D"-shaped shaft at one end of the laser rangefinder support bracket passes through the hollow shaft of the angle sensor and is fixed to it with set screws. When the laser rangefinder support bracket swings up and down under the action of the traction cable, the laser rangefinder support bracket and the hollow shaft of the angle sensor remain stationary, while the hollow shaft of the angle sensor rotates relative to the angle sensor, thus measuring the motion angle of the laser rangefinder.

[0062] like Figure 7 As shown, the reflector assembly includes a reflector flange 13 and a reflector 14. The reflector flange 13 is fixed to the traction cable 16 by set screws. The reflector 14 is made of black fiberglass and is connected to the reflector flange 13 by screws and nuts, thus fixing the reflector to the traction cable and maintaining a perpendicular relationship with the traction cable.

[0063] The working principle of the device of the present invention is as follows: the traction cable 16 is led out from the drive device 18, passes through the integrated pulley 6 in the positioning device body of the present invention, and is connected to the fixed position of the end motion platform 19. The point where the traction cable 16 contacts the integrated pulley 6 and leaves the integrated pulley is called the cable traction exit point. The fixed position where the traction cable is connected to the end motion platform 19 is called the anchor point.

[0064] The device is mounted on the frame of a planar four-cable, three-degree-of-freedom cable-driven parallel robot system via a main support 1. Under the action of the drive device 18, the end effector platform 19 moves in two-dimensional space, and the traction cable 16 moves with the end effector platform 19. When the end effector platform 19 swings left and right relative to the positioning device body under the action of the drive device 18, the traction cable 16 generates lateral pressure with the laser rangefinder support frame 9. The follower pin 3 of the exit point follower mechanism rotates under the action of the lateral pressure, ensuring that the laser emitted by the laser rangefinder 10 mounted on the laser rangefinder support frame 9 remains parallel to the traction cable 16. The exit point follower mechanism swings left and right under the action of the traction cable to counteract the axial force of the traction cable on the exit point follower mechanism.

[0065] When the end motion platform 19 swings up and down relative to the positioning device body, the traction cable 16 and the laser range sensor support frame 9 generate vertical pressure. Under the action of vertical pressure, the laser range sensor support frame 9 rotates around the axis of the integrated pulley 6, further ensuring that the laser emitted by the laser range sensor 10 installed on the laser range sensor support frame 9 remains parallel to the traction cable 16.

[0066] Simultaneously, the laser rangefinder 10, angle sensor 12, and photoelectric encoder 11 sensors measure the real-time data of the cable-driven parallel robot's operation. The rotation angle of the laser rangefinder support 9 is measured by the angle sensor 12 installed at one end of the laser rangefinder support 9, which approximates the rotational motion of the laser rangefinder 10.

[0067] The laser rangefinder support frame 9 has a through hole at one end for connecting to the counterweight block 15, thereby counteracting the friction on the traction cable caused by the weight of the laser rangefinder support frame 9 and the laser rangefinder 10.

[0068] The traction cable 16 is wound around the integrated pulley 6 from below the installation position of the integrated pulley 6. When the traction cable 16 is wound and unwound under the action of the traction cable drive device 18, the integrated pulley 6 remains relatively stationary with the traction cable under the action of friction. At this time, the rotation speed of the integrated pulley can be measured by the photoelectric encoder 11 installed at one end of the integrated pulley, thereby realizing the indirect measurement of the length of the traction cable.

[0069] By measuring the length of the traction cable and the rotation angle of the laser rangefinder sensor support frame, and combining the geometric relationships, the positions of each end-effector anchor point (marked as 1, 2, 3, 4 in the figure) in two-dimensional space can be calculated. Furthermore, based on the geometric characteristics of the end-effector 19, the attitude of the end-effector in space can be calculated.

[0070] like Figure 2 , 9 As shown in Figure 10, this embodiment of the invention provides a multimodal fusion localization method for a cable-driven parallel robot, comprising the following steps:

[0071] Step 1, during robot system operation, such as Figure 8 As shown, the four positioning device bodies of the present invention are respectively installed at the four corners of the two-dimensional plane of the planar four-cable three-degree-of-freedom cable traction parallel robot system. After the traction cable 16 is led out from the drive device 18, it is wound around the integrated fixed pulley 6 of the positioning device body, and passes through the cable routing hole in the laser range sensor support frame 9, and is finally fixed at the corresponding anchor point of the end motion platform 19.

[0072] Step 2: When the drive device 18 drives the end motion platform 19 to move in two-dimensional space, the traction cable 16 moves with the end motion platform 19, and the integrated pulley 6 rotates under the friction of the traction cable. The photoelectric encoder 11 fixed on the encoder bearing bracket 8 moves relative to the integrated pulley 6, and the photoelectric encoder collects the rotational motion of the integrated pulley.

[0073] Step 3: When the end motion platform 19 swings left and right relative to the positioning device body under the action of the drive device 18, the follower pin 3 rotates under the action of lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction cable 16 to ensure that the laser emitted by the laser range sensor 10 remains parallel to the traction cable 16.

[0074] When the end motion platform 18 swings up and down relative to the positioning device body, the laser range sensor support frame 9 rotates around the axis of the integrated pulley 6 under the action of vertical pressure, ensuring that the laser emitted by the laser range sensor 10 remains parallel to the traction cable 16; the angle sensor 12 measures the rotation angle of the laser range sensor support frame 9.

[0075] When the traction cable 16 is retracted or extended under the action of the traction cable drive device, the integrated pulley 6 is stationary relative to the traction cable. The photoelectric encoder 11 measures the rotational speed of the integrated pulley 6, and then measures the length of the traction cable.

[0076] The photoelectric encoder used as a displacement sensor is a 500-line incremental photoelectric encoder. It indirectly measures the displacement of the traction cable by measuring the rotation of the integrated pulley. The conversion relationship between the number of pulses collected by the photoelectric encoder and the cable displacement at the exit point is as follows:

[0077]

[0078] In the formula, L1 represents the displacement value of the traction cable at the exit point measured by the photoelectric encoder, in mm; n represents the number of pulses of the photoelectric encoder, unitless; D represents the minimum diameter of the pulley groove at the exit point, in mm; r represents the rope radius, in mm; θ represents the groove angle of the pulley at the exit point, in rad; and k represents the pulse-to-angle conversion coefficient, in rad. m represents the frequency multiplication factor of the hardware acquisition system. If frequency multiplication counting is not used, m is 1; when using double frequency multiplication counting, m is 2; and when using quadruple frequency multiplication counting, m is 4.

[0079] In this example, the photoelectric encoder uses the time-domain method for measurement, with a sampling frequency of 100Hz. The encoder will collect all encoder readings within 10ms.

[0080] Real-time displacement data of the traction cable is measured using a laser rangefinder sensor. Combined with the distance information between the reflector and the anchor point of the end motion platform 19 corresponding to the traction cable, this distance is taken as the traction cable length d, without considering external interference and the elastic elongation of the traction cable, and is calculated by the following formula:

[0081] d=βL1+(1-β)L2

[0082] Where β is a constant between 0 and 1, and in this example, it is taken as 0.2. L2 is the data of the displacement of the traction cable measured in real time by the laser rangefinder.

[0083] An angle sensor measures the angle between the traction cable and the y-axis of the positioning device's coordinate system at a certain moment, i.e., the angle measurement value of the positioning device is α. Combining the measured angle α, the real-time displacement data L2 of the traction cable measured by the laser rangefinder, and the calculated displacement value L1 of the traction cable at the exit point measured by the photoelectric encoder, based on the geometric relationship between the traction cable, the laser rangefinder, the reflector, and the anchor point of the end-effector platform, the position of the anchor point 19 of the end-effector platform connected to the device in two-dimensional space can be determined as follows:

[0084]

[0085] In the formula, x i y i Let α represent the x-axis coordinate and y-axis coordinate of the i-th anchor point of the end-effector 19 connected to the device in the two-dimensional coordinate system, respectively. i d represents the angle measurement value of the i-th positioning device body. i h is the fusion traction cable length of the i-th multimodal positioning device. i Let l represent the y-axis coordinate of the i-th integrated pulley axis in the two-dimensional coordinate system. i1 The distance l represents the distance from the laser emission point of the i-th laser rangefinder sensor to the axis of the integrated pulley along the traction cable axis. i2 This represents the distance along the traction cable from the reflecting surface of the i-th reflector to the anchor point of the end motion platform 19.

[0086] Assuming the end effector platform 19 of the cable-driven parallel robot is rectangular, the position of the anchor point of the end effector platform 19 connected to the i-th device in two-dimensional space, measured by the above method, is (x...). i ,y i Then, the position and attitude of the end effector platform 19 in two-dimensional space can be calculated as follows:

[0087]

[0088] In the formula, X and Y represent the x-axis and y-axis coordinates of the end effector platform in two-dimensional space, respectively; ω represents the angle of rotation of the end effector platform about an axis perpendicular to the plane in two-dimensional space; L represents the length of the end effector platform; W represents the width of the end effector platform; and x... 2i This represents the x-axis position of the 2i-th anchor point in space. 2i-1 This represents the x-axis position of the (2i-1)th anchor point in space, and y i This represents the y-axis position of the i-th anchor point in space. i+2 This represents the y-axis position of the (i+2)th anchor point in space.

[0089] This invention simplifies the measurement process of the operating status of the end-effector of a cable-driven parallel robot by directly measuring the position of the anchor point in space and combining the geometric features of the end-effector. It supports high-frequency fusion positioning of the end-effector of the cable-driven parallel robot, improves the reliability of the system, and achieves high-speed and high-precision positioning of the end-effector.

[0090] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A multimodal fusion positioning device for a cable-driven parallel robot, characterized in that, include: The exit point follow-up mechanism is fixed on the cable-traction parallel robot system. When the end motion platform moves, it is used to follow the left and right swing of the traction cable with the fixed pulley mechanism of the traction cable, so that the laser emitted by the laser range sensor remains parallel to the traction cable. The traction cable fixed pulley mechanism is used to pass the traction cable over the pulley of the traction cable fixed pulley mechanism, and rotate under the action of the change in the length of the traction cable to realize the change of direction of the traction cable; The laser rangefinder sensor follow-up measurement mechanism is configured as a laser rangefinder sensor support frame. The laser rangefinder sensor support frame is used to rotate around the axis of an integrated pulley when the traction cable swings up and down. The traction cable and the laser emitted by the laser rangefinder sensor remain parallel. The sensing and measuring device is used to measure in real time the speed of the traction cable, the angle between the traction cable and the vertical axis of the laser rangefinder sensor support frame, and the distance from the exit point of the traction cable fixed pulley mechanism to the reflector. A reflector device is mounted on the traction cable at a certain distance from the anchor point of the end motion platform to receive the laser emitted by the laser rangefinder and indirectly measure the length of the traction cable. The exit point follow-up mechanism includes a main support, a pin bearing support frame, a follow-up pin, and a pin positioning sleeve. The main support is fixed to the frame of the cable-driven parallel robot system, and the pin bearing support frame is installed above the main support. A deep groove ball bearing is provided on the pin bearing support frame. The follow-up pin is sleeved in the pin bearing support frame, and a retaining spring is installed on the pin. A pin positioning sleeve is sleeved under the pin bearing support frame. The laser ranging sensor follow-up measurement mechanism includes an encoder bearing bracket, an angle sensor bearing bracket, a laser ranging sensor support frame, a laser ranging sensor, and a counterweight. The laser ranging sensor support frame is connected to the angle sensor bearing bracket and the encoder bearing bracket via a top rotating arm, and a counterweight is connected to each of the pair of rotating arms. The laser rangefinder sensor support frame has a through hole for the traction cable, through which the traction cable passes and connects to the counterweight. The laser rangefinder sensor support frame has a cable routing hole at the center of its back, through which the traction cable passes after winding around the integrated pulley.

2. The multimodal fusion positioning device for cable-driven parallel robots according to claim 1, characterized in that, The traction cable fixed pulley mechanism includes a pulley support frame and an integral pulley mounted on the pulley support frame via a pin. The pulley support frame is a frame structure, with its top connected to a pin positioning sleeve.

3. The multimodal fusion positioning device for cable-driven parallel robots according to claim 1, characterized in that, The angle sensor bearing bracket and the encoder bearing bracket are connected side by side on both sides of the pulley support frame, and the laser rangefinder sensor is installed at the lower part of the laser rangefinder sensor support frame.

4. The multimodal fusion positioning device for cable-driven parallel robots according to claim 1, characterized in that, The sensing and measurement device includes a photoelectric encoder and an angle sensor, which are respectively fixed on the outside of the encoder bearing bracket and the angle sensor bearing bracket.

5. The multimodal fusion positioning device for cable-driven parallel robots according to claim 1, characterized in that, The reflector assembly includes a reflector flange and a reflector, which is fixed to the traction cable and kept perpendicular to the traction cable.

6. A positioning method for a multimodal fusion positioning device for a cable-driven parallel robot as described in any one of claims 1-5, characterized in that, include: The positioning device body is installed at the four corners of the two-dimensional plane of the planar four-cable three-degree-of-freedom cable traction parallel robot system. After the traction cable is led out from the drive device, it is wound around the integrated fixed pulley and passes through the cable routing hole of the laser range sensor support frame, and is fixed at the corresponding anchor point of the end motion platform. When the end motion platform swings left and right relative to the positioning device body under the action of the drive device, the follower pin rotates under the action of lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction cable to ensure that the laser emitted by the laser range sensor remains parallel to the traction cable. When the end motion platform swings up and down relative to the positioning device body, the laser range sensor support frame rotates around the integrated pulley axis under the action of vertical pressure, ensuring that the laser emitted by the laser range sensor remains parallel to the traction cable; When the traction cable moves in and out under the action of the traction cable drive device, the integrated pulley and the traction cable are relatively stationary. The photoelectric encoder measures the rotation of the integrated pulley to obtain the displacement of the traction cable. The displacement of the traction cable is measured in real time by the laser rangefinder sensor. Combined with the distance between the reflector and the anchor point of the corresponding end motion platform of the traction cable, the length of the traction cable is obtained. By measuring the angle between the traction cable and the positioning device body at a certain moment using an angle sensor, the position of the anchor point of the positioning device body connected to the end motion platform in two-dimensional space is obtained, and the position and attitude of the end motion platform in two-dimensional space are calculated.

7. The multimodal fusion positioning method for cable-driven parallel robots according to claim 6, characterized in that, The photoelectric encoder measures the rotation of the integrated pulley to obtain the displacement of the traction cable as follows: In the formula, This indicates that the photoelectric encoder measures the displacement value of the traction cable at the exit point; n Indicates the number of pulses in the photoelectric encoder; D Indicates the minimum diameter of the pulley groove at the outlet point; r Indicates the radius of the rope; Indicates the groove angle of the pulley at the outlet point; k Indicates the pulse-to-angle conversion coefficient; The length of the traction cable can be obtained by combining the distance between the reflector and the anchor point of the corresponding end motion platform of the traction cable: in β A constant between 0 and 1 Laser rangefinders measure the displacement data of the traction cable in real time. The positions of the anchor points of the end-effector motion platform connected to the positioning device body in two-dimensional space are as follows: In the formula, , These represent the x-coordinate and y-coordinate of the i-th anchor point of the end-effector motion platform connected to the device in the two-dimensional coordinate system, respectively. α i This represents the angle measurement value of the i-th positioning device body. d i It is the fused traction cable length of the i-th multimodal positioning device. ， This represents the y-axis coordinate of the i-th integrated pulley axis in a two-dimensional coordinate system. This represents the distance from the laser emission point of the i-th laser rangefinder sensor to the axis of the integrated pulley along the traction cable axis. This represents the distance along the traction cable from the reflecting surface of the i-th reflector to the anchor point of the end motion platform. The position and orientation of the end effector in two-dimensional space are as follows: In the formula, X , Y These represent the motion of the end effector platform along the two-dimensional space. x Axis coordinates and along y Axis coordinates L represents the angle of rotation of the end effector platform about an axis perpendicular to the plane in two-dimensional space, and L represents the length of the end effector platform. W Indicates the width of the end effector platform. This indicates the x-axis position of the 2i-th anchor point in space. This indicates the x-axis position of the (2i-1)th anchor point in space. This represents the y-axis position of the i-th anchor point in space. This represents the y-axis position of the (i+2)th anchor point in space.

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