Multi-modal fusion positioning device and positioning method for cable traction parallel robot

Abstract

The invention discloses a multi-modal fusion positioning device and method for a cable traction parallel robot. The multi-modal fusion positioning device comprises an outlet point follow-up mechanism fixed to a cable traction parallel robot system and a traction cable fixed pulley mechanism which follow up when a traction cable swings left and right; the traction cable fixed pulley mechanism is used for bypassing the traction cable from a pulley of the traction cable fixed pulley mechanism; the laser distance measuring sensor follow-up measuring mechanism is used for rotating around the axis of the integrated pulley when penetrating through the traction cable to swing up and down; the sensing measurement device is used for measuring the movement speed of the traction cable, the included angle between the traction cable and the vertical shaft and the distance between the traction cable and the reflecting plate from the outlet point in real time; and the reflecting plate device is used for receiving the laser emitted by the laser distance measuring sensor and indirectly measuring the length of the traction cable. By directly measuring the position of the anchor point of the tail end motion platform in the space, the pose of the tail end motion platform in the space is deduced, and high-speed and high-precision fusion positioning of the tail end motion platform of the high-frequency robot is achieved.

Description

Technical Field

[0001] The invention relates to a cable-pulled parallel robot, and in particular to a two-dimensional plane reconfigurable cable-pulled parallel robot multi-modal fusion positioning device and a positioning method. Background Art

[0002] The cable-driven parallel robot is a unique and advanced robot system. Its core is the cable-driven parallel mechanism, which enables it to achieve complex motion control and operation tasks. Compared with traditional rigid-connected robots, the cable-driven parallel robot has greater degrees of freedom, higher mobility and a wider workspace. The robot consists of multiple cables that are fixed to the frame. The drive system precisely controls the length and tension of the cables, allowing the robot to achieve flexible and varied movements with high flexibility.

[0003] As a special robot structure, the control accuracy of the cable-pulled parallel robot depends largely on the sensor measurement accuracy, which directly affects the position control of the robot. If the sensor measurement accuracy is insufficient, there will be a deviation between the actual position of the robot's end effector and the expected position, which will affect the robot's operating accuracy.

[0004] In high-speed or complex dynamic environments, cable-driven parallel robots need to respond to external commands quickly and accurately and adjust their own states. Sensors are required to have high sampling rates, low latency, and high stability to ensure that the robot's motion state changes are captured in real time and accurately. If the sensor performance is poor, it may cause hysteresis, jitter, or loss of control during the dynamic control process, seriously affecting the robot's operating efficiency and safety.

[0005] The sensor measurement accuracy is also closely related to the load distribution and balance control of the robot. In a cable-pulled parallel robot, accurate load distribution and balance relationships need to be maintained between each rope and pulley to ensure the stability and rigidity of the robot's overall structure. If the sensor cannot accurately measure the tension of each rope or the position change of the pulley, the load distribution and balance control will be affected, which may cause the robot structure to deform, vibrate, or fail.

[0006] The existing methods for positioning the terminal motion platform of a cable-driven parallel robot mainly include: 1) using an encoder to measure the rotational motion of the motor to indirectly measure the displacement of the traction cable, and solving the position and posture of the terminal motion platform through the forward kinematics equation. The displacement of the traction cable measured by this method is an approximate displacement, which ignores the cable displacement caused by the change in the wrap angle at the pulley at the exit point and the interference from the environment. The measured cable length is inaccurate, and the forward kinematics iterative optimization requires a lot of computing power, which is not suitable for real-time measurement; 2) using multiple fixed cameras mounted on the frame to measure the relative position of the marker points on the terminal motion platform, and measuring the position and posture of the terminal motion 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 higher-frequency closed-loop control; 3) The traditional measurement platform is located outside the cable-driven parallel robot system, occupies a large space, is easily affected by environmental interference, and cannot be flexibly deployed. Summary of the invention

[0007] In order to solve the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a multimodal fusion positioning device and positioning method for a cable-driven parallel robot, which adopts laser ranging sensors, photoelectric encoders and angle sensor information to measure the exit point information, and calculates the position of the anchor point of the terminal motion platform in space through the two-dimensional spatial geometric relationship, thereby calculating the posture of the terminal motion platform in space to realize the indirect measurement of the posture of the cable-driven parallel robot.

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

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

[0010] The exit point follower mechanism is fixed on the cable traction parallel robot system. When the terminal motion platform moves, it is used to follow the traction cable fixed pulley mechanism when the traction cable swings left and right, so that the laser emitted by the laser ranging sensor remains parallel to the traction cable;

[0011] The traction rope fixed pulley mechanism is used to pass the traction rope around the pulley of the traction rope fixed pulley mechanism, and rotate under the effect of the change of the traction rope length to realize the traction rope change of direction;

[0012] The laser distance sensor follow-up measuring mechanism is configured as a laser distance sensor support frame, and the laser distance sensor support frame is used to rotate around the axis of the integrated pulley when passing through the traction rope and swinging up and down, and the traction rope and the laser emitting from the laser distance sensor are kept parallel;

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

[0014] The reflector device is arranged on the traction cable at a certain distance from the anchor point of the terminal motion platform, and is used to receive the laser emitted by the laser ranging sensor and indirectly measure the length of the traction cable.

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

[0016] Preferably, the traction cable fixed pulley mechanism comprises a pulley support frame and an integrated pulley mounted on the pulley support frame via a pin shaft, and the pulley support frame is a frame structure, and the top is connected to a pin shaft 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 in parallel on both sides of the pulley support frame. The laser ranging sensor support frame is connected to the angle sensor bearing bracket and the encoder bearing bracket through a top rotating arm. Counterweights are respectively connected to a pair of rotating arms. The laser ranging sensor is installed at the bottom of the laser ranging sensor support frame.

[0018] Preferably, a traction rope through hole is opened on the rotating arm of the laser ranging sensor support frame, and the traction rope passes through the through hole to connect to the counterweight block.

[0019] Preferably, a cable arrangement hole is provided at the center line of the back of the laser ranging sensor support frame, and the traction rope passes through the cable arrangement hole after being wound around the integrated pulley.

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

[0021] Preferably, the reflector device comprises a reflector flange and a reflector, and the reflector is fixed on the traction rope and remains perpendicular to the traction rope.

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

[0023] The positioning device body is 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 is led out from the driving device, it is wound on the integrated fixed pulley, passes through the cable arrangement hole of the laser ranging sensor support frame, and is fixed to the corresponding anchor point of the terminal motion platform;

[0024] When the end motion platform swings left and right relative to the positioning device body under the action of the driving device, the follower pin rotates under the action of the lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction rope, ensuring that the laser emitted by the laser ranging sensor remains parallel to the traction rope;

[0025] When the end motion platform swings up and down relative to the positioning device body, the laser distance sensor support frame rotates around the integrated pulley axis under the vertical pressure to ensure that the laser emitted by the laser distance sensor remains parallel to the traction rope; the angle sensor measures the rotation angle of the laser distance sensor support frame;

[0026] When the traction rope is retracted and extended under the action of the traction rope driving device, the integrated pulley and the traction rope are relatively stationary, and the photoelectric encoder measures the rotation speed of the integrated pulley, and then measures the length of the traction rope.

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

[0028] 1. The traction rope of the present invention is wound on the traction rope fixed pulley mechanism. When the driving device controls the terminal motion platform to move in space and causes the device to swing left and right, the exit point following mechanism in the device moves to offset the axial force of the traction rope on the pulley, thereby ensuring that the exit point parameters remain unchanged and improving the stability of system operation; when swinging up and down, the laser ranging sensor support frame rotates around the integrated pulley axis, so that the laser emitted by the laser ranging sensor remains parallel to the traction rope; and the rotation angle of the laser ranging sensor support frame is accurately obtained.

[0029] 2. The laser ranging sensor, photoelectric encoder, angle sensor and other follow-up measuring mechanism sensors in the device are used to collect the length of the traction rope, the speed of the traction rope and the angle between the traction rope and the y-axis of the coordinate system in real time. The laser ranging sensor, angle sensor and photoelectric encoder are used in combination with a high sampling frequency, and the comprehensive sampling frequency can reach up to 100Hz; it supports closed-loop motion control of the cable-traction parallel robot at medium and high speeds, can avoid problems such as unstable robot motion, response delay, and reduced control accuracy caused by untimely feedback, and realizes medium-high speed and high-precision positioning of the terminal motion platform.

[0030] 3. While using the photoelectric encoder to directly measure the length of the traction rope, a combination of a laser ranging sensor and a reflector is used to indirectly measure the length of the traction rope. The two sensors measure simultaneously to improve the reliability of the traction rope length measurement value and reduce the error caused by environmental interference, thereby improving the accuracy of the robot's motion control, with small calculation amount and strong real-time performance.

[0031] 4. The sensor is arranged near the exit point to reduce the impact of environmental factors on sensor measurement and improve the stability of system operation.

[0032] 5. Compared with dynamic vision measurement and laser tracking measurement systems, this device integrates the exit point follow-up mechanism, laser ranging sensor follow-up measurement mechanism, traction cable fixed pulley mechanism, sensor measurement device, and reflector device into the cable traction parallel robot system. It has a compact structure, is stable and reliable, and is flexible to deploy.

[0033] 6. By installing a counterweight on the laser sensor support frame, the load of the laser ranging sensor support frame and the laser ranging sensor on the traction cable is balanced, and the support frame bearing is used to reduce the torque caused by friction when the laser sensor support frame rotates, reduce the impact of the device on the tension of the traction cable, and comprehensively improve the stability and reliability of the device operation.

[0034] 7. By directly measuring the position of the anchor point of the terminal motion platform in space, combined with the geometric characteristics of the terminal motion platform, the position and posture of the terminal motion platform in space are indirectly derived through geometric relationships, avoiding the use of numerical optimization and other methods to solve the positive kinematics of the terminal motion platform posture. This simplifies the measurement process of the operating state of the terminal motion platform of the cable-traction parallel robot, provides a new terminal posture measurement scheme for the cable-traction parallel robot, realizes automatic wiring of the traction cable exit point, and increases the terminal posture measurement frequency of the cable-traction parallel robot, thereby improving the dynamic performance of the robot system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0036] Figure 1 It is a schematic diagram of the structure of a multi-modal fusion positioning device for a cable-pulled parallel robot;

[0037] Figure 2 It is a schematic diagram of the robot's multi-modal positioning operation state;

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

[0039] Figure 4 This is a schematic diagram of the follow-up measurement mechanism of the laser ranging sensor;

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

[0041] Figure 6 is a schematic diagram of the sensor measurement device;

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

[0043] Figure 8 It is a schematic diagram of the displacement state of the traction cable measured by the multi-modal fusion positioning device;

[0044] Fig. 9 It is a schematic diagram of the measurement of the device anchor point position;

[0045] Fig.10 This is a schematic diagram of robot posture measurement.

[0046] In the figure: 1-main bracket, 2-pin bearing support frame, 3-follow-up pin, 4-pin positioning sleeve, 5-pulley support frame, 6-integrated pulley, 7-angle sensor-bearing bracket, 8-encoder bearing bracket, 9-laser ranging sensor support frame, 10-laser ranging sensor, 11-photoelectric encoder, 12-angle sensor, 13-reflector flange, 14-reflector, 15-counterweight, 16-traction rope, 17-bearing, 18-traction rope drive device, 19-end motion platform. DETAILED DESCRIPTION

[0047] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary 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, an embodiment of the present invention provides a cable-traction parallel robot multimodal fusion positioning device, including an exit point following mechanism, a traction cable pulley mechanism, a laser ranging sensor following measurement mechanism and a sensing and measuring device to form a positioning device body; the exit point following mechanism is located at the top of the mechanism, the traction cable pulley mechanism is connected below the exit point following mechanism, the laser ranging sensor following measurement mechanism is connected to the traction cable pulley mechanism, and the sensing and measuring device is installed on both sides of the laser ranging sensor following measurement mechanism; it also includes a reflector device on the traction cable at a certain distance from the anchor point of the terminal motion platform, which is used to receive the laser emitted by the laser ranging sensor to indirectly measure the length of the traction cable.

[0049] The main body of the positioning device is fixed on the four corners of the planar four-cable three-degree-of-freedom cable-traction parallel robot system. The traction cable 16 bypasses the traction cable pulley mechanism, passes through the hole of the laser ranging sensor follow-up measurement mechanism, and one end passes through the reflector device and is fixed on the terminal motion platform 19, and the other end is fixed on the driving device 18. Under the action of the driving device 18, the traction cable moves with the terminal motion platform 19, and the sensing and measuring device obtains the distance between the exit point follow-up mechanism and its corresponding terminal motion platform 19 anchor point, and calculates the posture of the terminal motion platform 19 in space.

[0050] Among them, Figure 3As shown, the exit point follower mechanism includes: a main bracket 1, a pin bearing support frame 2, a follower pin 3 and a pin positioning sleeve 4. The main bracket 1 is fixed to the frame of the cable traction parallel robot system, and the pin bearing support frame 2 is installed on the upper surface of the main bracket 1. A deep groove ball bearing is installed on the pin bearing support frame 2. A follower pin 3 is sleeved in the inner ring of the pin bearing support frame 2, and grooves are opened at both ends of the pin. A retaining spring is installed at the groove at one end of the pin, and the end face of the retaining spring contacts the upper surface bearing of the pin bearing support frame 2, thereby axially positioning the upper surface bearing. A pin positioning sleeve 4 is sleeved on the lower surface bearing of the pin bearing support frame 2, and one end of the sleeve contacts the inner ring of the lower surface bearing of the pin bearing support frame 2 to achieve axial positioning of the lower surface bearing, and 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 to achieve axial positioning of the pin positioning sleeve. When the terminal motion platform moves, it follows the traction cable of the traction cable fixed pulley mechanism when the traction cable swings left and right.

[0051] The traction rope fixed pulley mechanism includes an integrated pulley 6 and a pulley support frame 5. The pulley support frame 5 is a frame structure, and the top is connected to the pin shaft positioning sleeve 4. The integrated pulley 6 is fixed to the pulley support frame 5 through the pin shaft. The pulley support frame 5 is provided with a through hole to facilitate the assembly of the follower pin shaft. The pulley support frame 5 is processed as a whole 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 shaft. The end face of the retaining spring contacts the lower surface of the pulley support frame to achieve axial positioning of the pulley support frame 2. Under the action of the preload force generated when the retaining springs at both ends are installed, there is friction between the pulley support frame 5 and the follower pin shaft. When the pulley support frame rotates, the follower pin shaft 3 is stationary relative to the pulley support frame. It rotates under the action of the change in the length of the traction rope to achieve the change of direction of the traction rope.

[0052] like Figure 4 , Figure 5 and Figure 6 As shown, the laser distance sensor follow-up measurement mechanism includes: encoder bearing bracket 8, angle sensor bearing bracket 7, laser distance sensor support bracket 9, laser distance sensor 10 and counterweight 15. Two frame-type frames are connected in parallel on both sides of the pulley support bracket 5, which are the angle sensor bearing bracket 7 and the encoder bearing bracket 8. Both sides of the angle sensor bearing bracket 7 and the encoder bearing bracket 8 are coaxially installed with bearings 17 with the integrated pulley 6.

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

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

[0055] A traction cable through hole is opened on the rotating arm of the laser ranging sensor support frame 9, and the traction cable 16 passes through the through hole to connect the counterweight block 15. The counterweight block 15 is used to offset the friction caused by the weight of the laser ranging sensor support frame 9 and the laser ranging sensor 10. Two threaded holes are designed on the counterweight block 15, and the force arms at the left and right ends balance each other.

[0056] like Figure 8 As shown, a cable arrangement hole is provided at the midline of the back of the laser ranging sensor support frame 9, and the traction rope 16 passes through the cable arrangement hole after winding around the integrated pulley 6. When the traction rope swings up and down around the integrated pulley under the action of the terminal motion platform 19, the traction rope generates positive pressure on the laser ranging sensor support frame 9, and the laser ranging sensor support frame swings up and down with the traction rope under the action of the positive pressure.

[0057] The laser ranging sensor uses the pulse TOF method to measure the distance value, and the maximum sampling frequency is 100Hz.

[0058] When the laser distance sensor follow-up measurement mechanism is in operation, the traction rope passes through the traction rope arrangement hole on the laser distance sensor support frame. When the end platform moves and the traction rope swings up and down, the laser distance sensor support frame swings up and down under the positive pressure of the traction rope to ensure that the traction rope and the laser distance sensor emitter remain parallel. At the same time, the counterweight block is installed at the tail end of the laser distance sensor support frame to offset the torque of the laser distance sensor on the axis, prevent the device from interfering with the traction rope and applying additional rope tension.

[0059] In one embodiment, the integrated pulley is processed using a lathe, and the left and right ends are asymmetrically designed with the pulley as the center, wherein the pulley cross section is "V" shaped, the left end shaft of the pulley is a three-step long shaft, and the right end shaft of the pulley is a two-step short shaft. The shoulder end face between the first and second steps of the pulley long shaft contacts the inner ring of the bearing of the encoder-bearing bracket inner side bearing, and the shoulder end face between the first and second steps of the pulley short shaft contacts the inner ring of the bearing of the angle sensor-bearing bracket inner side bearing, so as to realize the axial positioning of the integrated pulley. The traction rope is led out from the driving device 18 and wound in the "V" shaped groove of the integrated pulley. When the traction rope moves under the action of the driving device 18, the integrated pulley rotates relatively under the action of friction.

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

[0061] The photoelectric encoder frame is designed with threaded through holes, which are fixed to the encoder bearing bracket 8 by screws and nuts. The photoelectric encoder code disc axis and the side of the code disc are designed with threaded through holes, which are fixed to the third step of the long axis of the integrated pulley by set screws. When the integrated pulley rotates under the friction of the traction rope, the photoelectric encoder code disc is stationary relative to the integrated pulley, and the photoelectric encoder reader is fixed to the encoder bearing bracket by M2 screws. Read the relative movement of the code disc. The center of the angle sensor is a hollow shaft. During assembly, the "D"-shaped shaft at one end of the laser ranging sensor support frame penetrates the hollow shaft of the angle sensor and is fixed to the hollow shaft of the angle sensor by set screws. When the laser ranging sensor support frame swings up and down under the action of the traction rope, the laser ranging sensor support frame and the hollow shaft of the angle sensor remain stationary, and the hollow shaft of the angle sensor rotates relative to the angle sensor, thereby measuring the movement angle of the laser ranging sensor.

[0062] like Figure 7 As shown, the reflector device includes a reflector flange 13 and a reflector 14. The side of the reflector flange 13 is fixed to the traction rope 16 by a set screw. The reflector 14 is processed with black glass fiber and connected to the reflector flange 13 by screws and nuts, so that the reflector is fixed on the traction rope and maintains a vertical relationship with the traction rope.

[0063] The working principle of the device of the present invention is that the traction rope 16 is led out from the driving 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 terminal motion platform 19, wherein the traction rope 16 contacts the integrated pulley 6, and the point where the traction rope leaves the integrated pulley is called the rope traction exit point, and the fixed position where the traction rope is connected to the terminal motion platform 19 is called the anchor point.

[0064] The device is installed on the frame of a planar four-cable three-degree-of-freedom cable-traction parallel robot system through a main bracket 1. Under the action of a driving device 18, a terminal motion platform 19 moves in a two-dimensional space, and a traction cable 16 moves with the terminal motion platform 19; when the terminal motion platform 19 swings left and right relative to the positioning device body under the action of the driving device 18, the traction cable 16 and the laser ranging sensor support frame 9 generate lateral pressure, and 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 ranging sensor 10 installed on the laser ranging sensor support frame 9 maintains a parallel relationship with the traction cable 16; the exit point follower mechanism swings left and right under the action of the traction cable to offset 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 rope 16 and the laser distance sensor support frame 9 generate vertical pressure, and the laser distance sensor support frame 9 rotates around the axis of the integrated pulley 6 under the vertical pressure, further ensuring that the laser emitted by the laser distance sensor 10 installed on the laser distance sensor support frame 9 maintains a parallel relationship with the traction rope 16;

[0066] At the same time, the laser distance sensor 10, the angle sensor 12 and the photoelectric encoder 11 sensors measure the real-time data of the cable-pulled parallel robot in real time. The angle sensor 12 installed at one end of the laser distance sensor support frame 9 measures the rotation angle of the laser distance sensor support frame 9, and the rotation movement of the laser distance sensor 10 is approximately measured.

[0067] One end of the laser distance sensor support frame 9 is designed with a through hole for connecting with the counterweight 15, so as to offset the friction effect on the traction rope caused by the self-weight of the laser distance sensor support frame 9 and the laser distance sensor 10.

[0068] The traction rope 16 is wound around the integrated pulley 6 from below the installation position of the integrated pulley 6. When the traction rope 16 is retracted and released under the action of the traction rope driving device 18, the integrated pulley 6 remains relatively still with the traction rope due to the friction force. 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 indirect measurement of the traction rope length.

[0069] By measuring the length of the traction rope and the rotation angle of the laser ranging sensor support frame, and combining the geometric relationship, the position of each terminal motion platform anchor point (marked 1, 2, 3, 4 in the figure) in the two-dimensional space can be calculated, and the posture of the terminal motion platform in space can be further calculated based on the geometric characteristics of the terminal motion platform 19.

[0070] like Figure 2 , 9 As shown in 10, an embodiment of the present invention provides a multi-modal fusion positioning method for a cable-driven parallel robot, comprising the following steps:

[0071] Step 1: When the robot system is running, Figure 8 As shown, 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 driving device 18, it is wound on the integrated fixed pulley 6 of the positioning device body, and passes through the cable arrangement hole in the laser ranging sensor support frame 9, and is finally fixed to the corresponding anchor point of the terminal motion platform 19;

[0072] Step 2, when the driving device 18 drives the terminal motion platform 19 to move in a two-dimensional space, the traction rope 16 moves with the terminal motion platform 19, the integrated pulley 6 rotates under the friction force of the traction rope, and 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 terminal motion platform 19 swings left and right relative to the positioning device body under the action of the driving device 18, the follower pin 3 rotates under the action of the lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction rope 16, ensuring that the laser emitted by the laser ranging sensor 10 remains parallel to the traction rope 16;

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

[0075] When the traction rope 16 is retracted and extended under the action of the traction rope driving device, the integrated pulley 6 and the traction rope are relatively stationary, and the photoelectric encoder 11 measures the rotation speed of the integrated pulley 6 and further measures the length of the traction rope.

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

[0077]

[0078] Wherein, L1 represents the displacement value of the traction rope at the exit point measured by the photoelectric encoder, in mm; n represents the number of pulses of the photoelectric encoder, without unit; 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 pulley groove angle at the exit point, in rad; k represents the pulse-angle conversion coefficient, in rad, m represents the frequency multiplication factor of the hardware acquisition system. If the frequency multiplication count is not used, m is 1. When the double frequency count is used, m is 2. When the quadruple frequency count is used, m is 4.

[0079] In this example, the photoelectric encoder measurement method is the time domain method, and the sampling frequency is set to 100 Hz. The encoder will collect all encoder readings within 10 ms.

[0080] The data of the traction cable displacement is measured in real time by the laser ranging sensor, combined with the distance information between the reflector and the anchor point of the end motion platform 19 corresponding to the traction cable. Without considering external interference and elastic elongation of the traction cable, this distance is regarded as the traction cable length d, which is calculated by the following formula:

[0081] d = βL1 + (1-β)L2

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

[0083] The angle sensor measures the angle between the traction rope and the y-axis of the coordinate system of the positioning device body at a certain moment, that is, the angle measurement value of the positioning device body is α. Combining the above-mentioned measured angle α and the data L2 of the traction rope displacement measured in real time by the laser ranging sensor, and the calculated value photoelectric encoder measured the traction rope displacement value L1 at the exit point, according to the geometric relationship between the traction rope, the laser ranging sensor, the reflector and the anchor point of the terminal motion platform, the position of the anchor point of the terminal motion platform 19 connected to the device in two-dimensional space can be measured as follows:

[0084]

[0085] In the formula, x i ,y i They respectively represent the x-axis coordinate and the y-axis coordinate of the i-th anchor point of the terminal motion platform 19 connected to the device in the two-dimensional coordinate system, α i represents the angle measurement value of the i-th positioning device body, d i is the length of the fused traction cable of the i-th multimodal positioning device, h i represents the y-axis coordinate of the i-th integrated pulley axis in the two-dimensional coordinate system, l i1 represents the distance from the laser emission point of the i-th laser ranging sensor to the axis of the integrated pulley along the axis of the traction cable, l i2 It represents the distance from the reflection surface of the i-th reflection plate to the anchor point of the terminal motion platform 19 along the direction of the traction cable.

[0086] Assuming that the terminal motion platform 19 of the cable-pulled parallel robot is a rectangle, the position of the anchor point of the terminal motion platform 19 connected to the i-th device in the two-dimensional space is measured by the above method as (x i ,y i ), the position and posture of the terminal motion platform 19 in the two-dimensional space can be calculated as follows:

[0087]

[0088] In the formula, X and Y represent the x-axis coordinates and y-axis coordinates of the terminal motion platform in two-dimensional space, ω represents the angle of rotation of the terminal motion platform around the axis perpendicular to the plane in two-dimensional space, L represents the length of the terminal motion platform, W represents the width of the terminal motion platform, and x 2i represents the x-axis position of the 2i-th anchor point in space, x 2i-1 Indicates the x-axis position of the 2i-1th anchor point in space, y i Indicates the y-axis position of the i-th anchor point in space, y i+2 Indicates the y-axis position of the i+2th anchor point in space.

[0089] The present invention directly measures the position of the terminal motion platform anchor point in space, combines the geometric characteristics of the terminal motion platform, and deduces the position and posture of the terminal motion platform in space, thereby simplifying the measurement process of the operating status of the terminal motion platform of the cable-traction parallel robot, supporting higher-frequency fusion positioning of the terminal motion platform of the cable-traction parallel robot, improving the reliability of the system, and realizing high-speed and high-precision positioning of the terminal motion platform.

[0090] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A multi-modal fusion positioning device for a cable-pulled parallel robot, characterized in that: include: The exit point follower mechanism is fixed on the cable traction parallel robot system. When the terminal motion platform moves, it is used to follow the traction cable fixed pulley mechanism when the traction cable swings left and right, so that the laser emitted by the laser ranging sensor remains parallel to the traction cable; The traction rope fixed pulley mechanism is used to pass the traction rope around the pulley of the traction rope fixed pulley mechanism, and rotate under the effect of the change of the traction rope length to realize the traction rope change of direction; The laser distance sensor follow-up measuring mechanism is configured as a laser distance sensor support frame, and the laser distance sensor support frame is used to rotate around the axis of the integrated pulley when passing through the traction rope and swinging up and down, and the traction rope and the laser emitting from the laser distance sensor are kept parallel; The sensing and measuring device is used to measure in real time the moving speed of the traction rope, the angle between the traction rope and the vertical axis of the laser distance sensor support frame, and the distance between the traction rope and the exit point of the traction rope fixed pulley mechanism to the reflector; The reflector device is arranged on the traction cable at a certain distance from the anchor point of the terminal motion platform, and is used to receive the laser emitted by the laser ranging sensor and indirectly measure the length of the traction cable.

2. The multi-modal fusion positioning device of the cable-driven parallel robot according to claim 1, characterized in that: The exit point follower mechanism includes a main bracket, a pin bearing support frame, a follower pin and a pin positioning sleeve. The main bracket is fixed to the frame of the cable-traction parallel robot system, and the pin bearing support frame is installed above the main bracket; a deep groove ball bearing is provided on the pin bearing support frame; a follower 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.

3. The multi-modal fusion positioning device of the cable-driven parallel robot according to claim 1, characterized in that: The traction rope fixed pulley mechanism comprises a pulley support frame and an integrated pulley installed on the pulley support frame through a pin shaft. The pulley support frame is a frame structure, and the top is connected to a pin shaft positioning sleeve.

4. The multi-modal fusion positioning device of the cable-driven parallel robot according to claim 1, characterized in that: The laser ranging sensor follow-up measurement mechanism includes an encoder bearing bracket, an angle sensor bearing bracket, a laser ranging sensor support bracket, a laser ranging sensor and a counterweight. The angle sensor bearing bracket and the encoder bearing bracket are connected in parallel on both sides of the pulley support bracket. The laser ranging sensor support bracket is connected to the angle sensor bearing bracket and the encoder bearing bracket through a top rotating arm. A pair of rotating arms are respectively connected to counterweights. The laser ranging sensor is installed at the bottom of the laser ranging sensor support bracket.

5. The multi-modal fusion positioning device of the cable-driven parallel robot according to claim 4, characterized in that: A traction rope through hole is provided on the rotating arm of the laser distance measuring sensor support frame, and the traction rope passes through the through hole to be connected to the counterweight block.

6. The multi-modal fusion positioning device of the cable-driven parallel robot according to claim 4, characterized in that: A cable arrangement hole is provided at the center line of the back of the laser ranging sensor support frame, and the traction rope is passed through the cable arrangement hole after being wound around the integrated pulley.

7. The multi-modal fusion positioning device of a cable-driven parallel robot according to claim 1, characterized in that: The sensing and measuring device comprises a photoelectric encoder and an angle sensor, and the photoelectric encoder and the angle sensor are respectively fixed on the outer sides of the encoder bearing bracket and the angle sensor bearing bracket.

8. The multi-modal fusion positioning device of a cable-driven parallel robot according to claim 1, characterized in that: The reflector device comprises a reflector flange and a reflector. The reflector is fixed on the traction rope and is kept perpendicular to the traction rope.

9. A positioning method for a multi-modal fusion positioning device of a cable-driven parallel robot according to any one of claims 1 to 8, characterized in that: include: The positioning device body is 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 is led out from the driving device, it is wound on the integrated fixed pulley, passes through the cable arrangement hole of the laser ranging sensor support frame, and is fixed to the corresponding anchor point of the terminal motion platform; When the end motion platform swings left and right relative to the positioning device body under the action of the driving device, the follower pin rotates under the action of the lateral pressure, and the exit point follower mechanism swings left and right under the action of the traction rope, ensuring that the laser emitted by the laser ranging sensor remains parallel to the traction rope; When the end motion platform swings up and down relative to the positioning device body, the laser distance sensor support frame rotates around the axis of the integrated pulley under the vertical pressure to ensure that the laser emitted by the laser distance sensor remains parallel to the traction cable; When the traction rope is retracted and extended under the action of the traction rope driving device, the integrated pulley and the traction rope are relatively stationary, and the photoelectric encoder measures the rotation of the integrated pulley to obtain the displacement of the traction rope; the displacement of the traction rope is measured in real time by the laser ranging sensor, and the distance between the reflector and the anchor point of the end motion platform corresponding to the traction rope is combined to obtain the length of the traction rope; The angle between the traction rope and the positioning device body at a certain moment is measured by the angle sensor, the position of the anchor point of the positioning device body connected to the terminal motion platform in the two-dimensional space is obtained, and the position and posture of the terminal motion platform in the two-dimensional space are calculated.

10. The multi-modal fusion positioning method of a cable-driven parallel robot according to claim 9, characterized in that: The photoelectric encoder measures the rotation of the integrated pulley and obtains the displacement of the traction rope as follows: Where, L1 represents the displacement value of the traction rope at the exit point measured by the photoelectric encoder; n represents the number of pulses of the photoelectric encoder; D represents the minimum diameter of the pulley groove at the exit point; r represents the rope radius; θ represents the pulley groove angle at the exit point; k represents the pulse-angle conversion coefficient; Combined with the distance between the reflector and the anchor point of the end motion platform corresponding to the traction cable, the length of the traction cable is obtained: d = βL1 + (1-β)L2 Where β is a constant between 0 and 1, and L2 is the displacement data of the traction cable measured in real time by the laser ranging sensor; The position of the anchor point of the terminal motion platform connected to the positioning device body in two-dimensional space is as follows: In the formula, x i ,y i They represent the x-axis coordinate and y-axis coordinate of the i-th anchor point of the terminal motion platform connected to the device in the two-dimensional coordinate system, respectively. i represents the angle measurement value of the i-th positioning device body, d i is the length of the fused traction cable of the i-th multimodal positioning device, h i represents the y-axis coordinate of the i-th integrated pulley axis in the two-dimensional coordinate system, l i1 represents the distance from the laser emission point of the i-th laser ranging sensor to the axis of the integrated pulley along the axis of the traction cable, l i2 It represents the distance from the reflection surface of the i-th reflection plate to the anchor point of the terminal motion platform along the traction cable direction; The position and posture of the terminal motion platform in two-dimensional space are as follows: In the formula, X and Y represent the x-axis coordinates and y-axis coordinates of the terminal motion platform in two-dimensional space, ω represents the angle of rotation of the terminal motion platform around the axis perpendicular to the plane in two-dimensional space, L represents the length of the terminal motion platform, W represents the width of the terminal motion platform, and x 2i represents the x-axis position of the 2i-th anchor point in space, x 2i-1 Indicates the x-axis position of the 2i-1th anchor point in space, y i Indicates the y-axis position of the i-th anchor point in space, y i+2 Indicates the y-axis position of the i+2th anchor point in space.

Images