Multi-degree-of-freedom rope-driven discrete type mechanical arm

Abstract

The invention discloses a multi-degree-of-freedom rope-driven discrete type mechanical arm which is composed of a rope-driven mechanical arm body, a rack and a rear sliding table. The rope-driven mechanical arm is composed of a tail end mechanical hand, a tail end guide rod, a middle guide rod, a stretching reset spring, an angular contact bearing, a bearing cover, a universal joint, a shifting block, a sliding rod, a guide flat key, a compression reset spring and a guide rod base assembly. The machine frame is composed of a frame body, a cradle mechanism, an electric slip ring, a transfer wheel and a worm and gear mechanism. By controlling a stepping motor on the rack, the circumferential rotation freedom degree of the cradle mechanism, the electric slip ring and the rope-driven mechanical arm around the main shaft is achieved through transmission of a worm and gear mechanism; through a stepping motor installed on the cradle mechanism, the tension of the two driving ropes is adjusted through a transfer wheel, and the two shifting blocks are controlled to move on the sliding rods. The reset compression spring and the stretching reset spring act together, and a sliding groove in the shifting block is matched with sliding grooves in the front portion and the rear portion of the middle guide rod to provide second to fifth rotation freedom degrees.

Description

Technical Field

[0001] The present invention relates to the field of robots, and more specifically, to a multi-degree-of-freedom rope-driven discrete robotic arm for complex space exploration and object picking. The present invention provides a solution for achieving multi-degree-of-freedom complex control using fewer motors, and can be combined with different components to achieve light-load grabbing, space exploration and other work tasks. The present invention can be widely used in industries such as pipeline operations and post-disaster rescue equipment. Background Art

[0002] Emergency rescue after accidents and disasters is of great significance to reducing the losses caused by emergencies. [2] , and one of the main reasons for most of the losses is that the complex cavity conditions caused by the earthquake cannot be detected in time, but professional detection equipment is expensive and complicated to operate. It is urgent to develop relatively cheap and easy-to-use detection equipment based on advanced robotics technology. To this end, the present invention proposes a multi-freedom, wire-controlled discrete catheter robot arm controlled by a few motors, which can greatly reduce the high cost and complex control caused by multiple motors, and the wire control system greatly improves the reliability and maintainability of the equipment. The present invention can reduce costs in three aspects: hardware, software, and operator training, thereby facilitating post-disaster rescue and engineering projects carried out in complex spatial backgrounds such as pipeline operations.

[0003] In the field of bionic robot design, according to the actuation principle of wire drive, combined with the slider slot design, the flexibility of the robot arm has been greatly improved, and the number of motors required has been reduced. While meeting the work needs, the manufacturing difficulty and cost are reduced. In the existing Chinese patent CN118061159A, an inflatable flexible manipulator is disclosed, which uses a rotating joint and a flexible joint to improve the flexibility of the manipulator. Some structures use a winch and a thin wire to improve the rigidity of the structure and realize the reset operation. However, the structural design is relatively complex and has limited flexibility, and it cannot work in a small space. In Chinese patent CN117644501A, a foldable rope-pulled parallel robot for dexterous operation in a small space is disclosed, in which the wire-driven manipulator at the end adopts a wire drive with high flexibility and flexibility, but compression springs are used as connections between the joints, and the accuracy is difficult to guarantee, and it is difficult to work under load. Chinese patent CN117415855A discloses a tendon-type rope-driven manipulator, which adopts a cross-shaped structure to improve the structural rigidity of the rope-driven manipulator, but at the same time has low flexibility and high cost of controlling four motors. Summary of the invention

[0004] In order to solve the problems mentioned in the technical background, the purpose of the present invention is to provide a low-cost, highly flexible and rigid robotic arm, which can be widely used in fields such as post-disaster rescue and pipeline operations.

[0005] The technical solution of the present invention is as follows: the robot arm is composed of a front catheter system, a frame system and a rear slide system, and the three are connected by a driving rope and serve as carriers for power transmission.

[0006] The front robotic arm is composed of the end guide rod, the middle guide rod, the shift block, the universal joint, the base guide rod, etc. During movement, the shift block is driven by the rope to move backward and is inserted into the rear slide slot in the guide rod. The universal joint limits the rotation of the shift block, thereby rotating the guide rod, and then the robotic arm is moved through the oblique planes at both ends of the guide rod. Similarly, when the tension of the thin rope decreases, the shift block is reset by the compression spring and enters the front slide slot at the same time, causing the guide rod to rotate further, allowing the robotic arm to work continuously. Such a middle guide rod and the end guide rod can achieve two degrees of rotational freedom around the center point of the universal joint, which can be controlled separately by the transfer wheel.

[0007] Furthermore, the worm gear mechanism drives the base guide rod to rotate, thereby realizing the rotational freedom of the robot arm around the main axis, thereby realizing the five degrees of freedom of the robot arm intermittently controlled by two motors.

[0008] Furthermore, based on the front robotic arm, a rope-driven manipulator is integrated and installed on the end guide rod to realize the grasping operation. At the same time, the matching rear slide system provides power to the manipulator drive rope through the slide to realize the grasping action.

[0009] The advantages of the present invention are: 1. The present invention provides a multi-degree-of-freedom rope-driven discrete manipulator with the advantages of low cost, high flexibility and good rigidity. The whole adopts rope-driven transmission, uses two motors to complete the five-degree-of-freedom control of the manipulator, and a slide table realizes the grasping of the manipulator, with low cost and control cost.

[0010] 2. The present invention has good adaptability and is not limited to a single end effector of the robot arm. It can also be adapted to other modules such as cameras. It only requires replacing the end effector and the rear slide.

[0011] 3. The present invention has excellent flexibility. The five-degree-of-freedom robotic arm can realize an accessible space that is approximately hemispherical, and the middle guide rod can further improve flexibility by increasing the number of units, and can be applied to complex working environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of a multi-degree-of-freedom rope-driven discrete manipulator of the present invention.

[0013] Figure 2 It is a cross-sectional view of a guide rod in the middle part of the front part of a multi-degree-of-freedom rope-driven discrete manipulator of the present invention.

[0014] Figure 3 The present invention is a schematic diagram of the operation of the rear slider of a multi-degree-of-freedom rope-driven discrete manipulator.

[0015] Figure 4 It is a working schematic diagram of the front slider of a multi-degree-of-freedom rope-driven discrete manipulator of the present invention.

[0016] Figure 5 It is a top sectional view of a multi-degree-of-freedom rope-driven discrete manipulator of the present invention.

[0017] Figure 6 It is a schematic diagram of a multi-degree-of-freedom rope-driven discrete manipulator end manipulator of the present invention.

[0018] Figure 7 The invention discloses a kinematic model of a multi-degree-of-freedom rope-driven discrete manipulator.

[0019] Figure 8 Schematic diagram of accessible space in the case of single middle guide rod and three middle guide rods of the present invention.

[0020] Fig. 9 It is a schematic diagram of the motion state of a multi-degree-of-freedom rope-driven discrete manipulator of the present invention. DETAILED DESCRIPTION

[0021] The present invention relates to the field of robots. In order to make the purpose, technical solutions and advantages of the present invention more clear, the specific implementation methods of the present invention are described in detail below with reference to the accompanying drawings. It should be pointed out that for ordinary technicians in this field, several changes and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0022] The technical solution adopted by the present invention is as follows: The multi-degree-of-freedom rope-driven discrete manipulator consists of a front manipulator, a frame and a rear slide (attached Figure 1 ), the three are connected by a driving rope and serve as carriers for power transmission.

[0023] The front robot arm is composed of the end guide rod, the middle guide rod, the shift block, the universal joint, the base guide rod, etc. (Attached Figure 2 ), driven by the driving rope during movement (attached Figure 5 ) drives the shift block to move backward and get stuck in the rear slot of the guide rod. The universal joint limits the rotation of the shift block, thereby driving the guide rod to rotate (attached Figure 3 ), and then the robot arm moves through the oblique planes at both ends of the guide rod. Similarly, when the tension of the drive rope decreases, the compression spring resets the shift block and enters the front slide (attached Figure 4), so that the guide rod rotates further, so that the robot arm can work continuously. In this way, the middle guide rod and the end guide rod can realize two rotational degrees of freedom θ2, θ3 and θ4, θ5 around the center point of the universal joint, which can be controlled separately by the transfer wheel.

[0024] At the same time, the worm gear mechanism on the frame drives the base guide rod to rotate, realizing the rotational freedom θ1 of the robot arm around the main axis, thereby realizing the five degrees of freedom of the robot arm intermittently controlled by two motors (see Appendix Figure 7 Based on the front robot arm, a rope-driven robot (attached Figure 6 ), installed on the end guide rod to achieve the grasping operation. At the same time, the matching rear slide system provides power to the manipulator drive rope through the slide to achieve the grasping action. Example

[0025] The multi-degree-of-freedom rope-driven discrete manipulator consists of a rope-driven manipulator, a frame and a rear slide, which are connected by a driving rope and serve as a carrier for power transmission.

[0026] The specific implementation process of the present invention is as follows: When it is necessary to explore or retrieve objects in a complex pipeline space, operate this system, and determine the first rotational freedom of the front mechanical arm (I) and the cradle structure 2-14 through the stepper motor 1-1 and the worm gear mechanism 2-16. Then control the stepper motor 1-2 on the cradle structure 2-14 to rotate a certain angle, increase the torque through the gear set 5-4, and control the tension of the two driving ropes 5-2 through the transfer wheel 5-5. One end of the driving rope is fixed to the block 2-8 by the clip 5-1, and the other end is fixed to the transfer wheel 5-4. When the tension of the driving rope 5-2 increases, the two shifting blocks 2-8 in the mechanical arm (I) move backward along the slide rod 2-9. When the shift block 2-8 moves backward a certain distance, it will be stuck in the rear slide groove 3-1 of the middle catheter. Under the constraint of the slide groove, it drives the middle guide rod 2-3 to rotate and the mechanical arm (I) to move. In this process, the tension spring 2-4 asymmetrically distributed around the catheter keeps the adjacent joints in contact at all times to maintain the normal operation of the mechanical arm. When the tension of the drive rope 5-2 decreases, under the push of the compression spring 2-11, the shift block 2-8 moves forward along the slide rod 2-9. When the shift block 2-8 moves forward a certain distance, it will be stuck in the front slide groove 4-1 of the middle catheter. Similarly, under the constraint of the slide groove, it drives the middle guide rod 2-3 to rotate and the mechanical arm (I) to move, completing a rotation operation. When the end manipulator 2-1 of the robot arm reaches the designated working position, the stepper motor 1-3 is operated, and the slider 2-18 is driven to move backward through the force-increasing effect of the slide 2-17. Three manipulator drive ropes 5-3 are fixed on the slider 2-18, and the other end thereof is fixed to the finger 6-3 on the end manipulator through the clip 6-2. When the tension of the manipulator drive rope 5-3 increases, the finger 6-3 will be gathered toward the center under the constraint of the wrist 6-4, and the end of the finger 6-3 is provided with a friction pad 6-1, which can increase the friction during grasping, thereby realizing the grasping function. When it is necessary to place the object to be grasped, it is only necessary to operate the stepper motor 1-3 to move the slider 2-18 forward, thereby reducing the tension on the manipulator drive rope 5-3, and the reset torsion spring 6-5 resets the finger 6-3 to realize the release of the grasped object.

[0027] The angle between the oblique planes at both ends of the middle guide rod 2-3 and the axis is 25 degrees, and the two oblique sections of each joint fit closely, which can achieve a 50-degree deflection from the axis. And because the worm gear 2-16, the electric slip ring 2-15 and the cradle structure 2-14 can all support full-circle rotation, therefore: θ1∈[-180°, 180°] θ2∈[-50°, 50°] θ3∈[-50°, 50°] θ4∈[-50°, 50°] θ5∈[-50°, 50°] The connecting rod length of the robot arm is a=67.5mm. Combining the above data and the kinematic model, the reachable space of the robot arm with two joints and five degrees of freedom and four joints and nine degrees of freedom can be calculated (see Appendix Figure 8 ). The reachable space of a two-joint five-degree-of-freedom robot arm is approximately a hemisphere, while the reachable space of a four-joint nine-degree-of-freedom robot arm is approximately a sphere. Both have excellent flexibility. (Appendix Fig. 9 ) The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-degree-of-freedom rope-driven discrete manipulator, characterized in that: It consists of a rope-driven mechanical arm, a frame and a rear slide; the rope-driven mechanical arm is located in the front of the frame, the end of the mechanical arm is fixed on the frame, and the rear slide is fixed above the tail of the frame; The rope-driven manipulator consists of an end manipulator, an end guide rod, a middle guide rod, a tension reset spring, an angular contact bearing, a bearing cover, a universal joint, a shift block, a slide rod, a guide flat key, a compression reset spring and a guide rod seat assembly; the guide rod seat is fixed on the frame, a middle guide rod passes through the middle, and the middle guide rod is connected to the slide rod through a universal joint, and a guide flat key, a shift block and a compression reset spring are installed on the middle guide rod; the slide rod is externally sleeved with the middle guide rod or the end guide rod, and an angular contact bearing and a bearing cover are installed on the outside of the middle guide rod, and a tension reset spring is asymmetrically arranged along the circumference on the bearing cover and connected to other guide rods; the end manipulator is installed on the end guide rod as an actuator to realize the grasping function; The frame consists of a frame body, a cradle mechanism, an electric slip ring, a transfer wheel and a worm gear mechanism; the cradle mechanism is installed on the frame body and is coaxially installed with the electric slip ring to facilitate signal transmission; the cradle mechanism is driven by a stepper motor installed on the frame through a worm gear mechanism to achieve 360-degree rotation relative to the frame body; a stepper motor is also installed on the cradle mechanism, and the motor is equipped with a transfer wheel to independently adjust the tension of the two drive ropes; The rear slide is composed of a slide and a slider; the slider is fixedly mounted on the slide, and under the drive of the slide, the slider moves along the slide relative to the frame; the slider is also installed concentrically with the aforementioned guide rod seat, cradle mechanism and electric slip ring; By controlling the stepper motor on the frame, the circumferential rotational freedom of the cradle mechanism, electric slip ring and rope-driven manipulator around the main axis is realized through the worm gear mechanism transmission, and precise control capability is possessed; by means of the stepper motor installed on the cradle mechanism, the tension of the two driving ropes is adjusted by the transfer wheel, thereby respectively controlling the movement of the two shifting blocks on the slide rod; the reset compression spring and the tension reset spring work together to realize the reset function, and the slide groove on the shifting block cooperates with the slide grooves at the front and rear parts of the middle guide rod to provide the second to fifth rotational freedoms; finally, the tension of the manipulator driving rope fixed on the end guide rod is adjusted by moving the slider on the slide forward and backward to realize the grasping control of the end manipulator.

2. The multi-degree-of-freedom rope-driven discrete manipulator according to claim 1, characterized in that: The robot arm is driven by a driving rope to move the shift block, which is inserted into the sliding grooves in front and behind the middle guide rod to move the robot arm and its terminal structure; a slide rod and a return compression spring are arranged on the axis of the guide rod, and a tension return spring is asymmetrically distributed on the outside of the guide rod, and the driving rope passes through the inside of the slide rod; a guide rod seat is fixedly installed on the frame, and the middle guide rod passes through the center of the guide rod seat, and the middle guide rod is connected to the slide rod through a universal joint; a guide flat key, a shift block and a compression return spring are installed on the middle guide rod; the middle guide rod or the terminal guide rod can be installed on the outside of the slide rod, and an angular contact bearing and a bearing cover are installed on the outside of the middle guide rod, and the tension return spring is asymmetrically arranged circumferentially on the bearing cover and connected to other guide rods; the terminal guide rod is equipped with an end manipulator as an actuator to realize the grasping function.

3. The multi-degree-of-freedom rope-driven discrete manipulator according to claim 1, characterized in that: The frame is coaxially equipped with a guide rod seat, a cradle mechanism, an electric slip ring, a worm gear and a slider to provide positioning and support, and is integrated with a stepper motor controller; the frame is provided with a dovetail groove; the cradle mechanism installed on the frame is coaxially arranged with the electric slip ring to facilitate signal transmission; the cradle mechanism is driven by a stepper motor installed on the frame through a worm gear mechanism to achieve 360-degree rotation relative to the frame; a stepper motor is also installed on the cradle mechanism with a transfer wheel to independently adjust the tension of the two drive ropes.

4. The multi-degree-of-freedom rope-driven discrete manipulator according to claim 1, characterized in that: The slide is powered and controlled by a stepper motor, which amplifies the output of force, allowing the slider to move back and forth along the slide, thereby affecting the tension of the robot drive rope and achieving grasping control of the robot.

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