Flexible cable driven series robot based on flexible joints and tension structure

Abstract

The invention discloses a flexible cable driven series robot based on flexible joints and a tension structure, which is characterized in that: 1, the structure of a mobile platform is optimized, and the mass of the platform is reduced on the premise of ensuring the rigidity; and 2, a novel tension structure is designed, mutual support among the mobile platforms is realized through scientific layout of the flexible cables among different mobile platforms, and the stability of the whole structure is enhanced. And 3, the flexible joint and the tensioning structure are innovatively combined in a modularized mode, and a motion bending structure of the series robot is achieved. And 4, three flexible cables are adopted to connect the mobile platform, so that the spatial three-degree-of-freedom movement of the series robot is realized. And 5, the control precision of the series robot is improved by using three groups of deceleration drivers, and the overall performance is optimized. The invention aims to provide the flexible cable driven series robot based on the flexible joints and the tension structure, and the flexible cable driven series robot has remarkable advantages in the aspects of improving the motion precision and stability, improving the flexibility, reducing the overall mass and the like, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the field of flexible cable driven serial robots, and in particular to the application of flexible cable driven serial robots which combine flexible joints with tensioning structures. Background Art

[0002] As the aging process in many countries intensifies, and the number of people whose physiological functions have deteriorated due to accidents or congenital diseases increases, these people need assistive devices to help them complete basic activities in their daily lives. As an important tool to meet this demand, assistive robots must prioritize safety when interacting with humans. Therefore, drawing on biological structures such as snakes, elephant trunks and octopus feet, assistive robots should adopt flexible structures to avoid causing harm to humans when they lose control. Flexible structures can not only adapt to highly dynamic environments, but also ensure safe interaction with humans, becoming an important technology to effectively help people with physiological function deterioration.

[0003] Considering the current development status of cable-driven serial robots, it has become a trend to use flexible structures instead of rigid connections. Robots with rigid connections are often limited by structural rigidity and are difficult to adapt to complex and dynamic working environments, especially when in contact with irregular objects or complex surfaces, which can easily lead to reduced operating accuracy and poor adaptability to the environment. In addition, robots with rigid connections usually require more complex mechanical designs and larger masses, which limits the flexibility and mobility of the robots.

[0004] Flexible structure robots can provide better flexibility and adaptability through changes in mechanical properties, allowing robots to better absorb external shocks and load changes when performing tasks, reduce environmental impact, and improve operational accuracy and stability. At the same time, they also show obvious advantages in lightweight, modular, simplified design, and reduced energy consumption. Compared with traditional rigid robots, flexible serial robots can reduce damage through elastic deformation during collisions and show stronger adaptability and safety in unstructured environments. Serial robots based on flexible structures have been widely used in human-computer interaction, medical rehabilitation, explosion-proof rescue and other fields, and have become an important tool for achieving safe and efficient operations. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention designs a novel cable-driven serial robot based on flexible joints and a tensioning structure.

[0006] In order to overcome the shortcomings of the prior art, the present invention designs a mobile platform, which serves as the main structure of the serial robot. The components are manufactured using one-piece molding technology and are divided into three parts. The upper layer is a cable fixer for fixing the tensegrity structure, the middle layer is used to fix the flexible joint mechanism, and the lower layer is used to fix the driving flexible cable and the tensegrity structure. The upper, middle and lower layers are connected in series through special-shaped connecting rods to be assembled into a mobile platform. While ensuring the rigidity of the mobile platform, the mass of the mobile platform is reduced and the production cost is reduced.

[0007] In order to overcome the shortcomings of the prior art, the present invention designs a fixed platform, which consists of two parts, namely a cable fixed support rod and an assembly platform. The cable fixed support rod is responsible for bearing all the gravity of the serial robot, and the assembly platform is responsible for assembling the flexible joint mechanism and fixing it to the operating platform.

[0008] In order to overcome the shortcomings of the prior art, the present invention proposes a flexible joint mechanism. The mechanism mainly includes three flexible joints, which are arranged in a uniform circular array at an angle of 120° between the mobile platform and the fixed platform. Each flexible joint consists of two parts, namely a flexible mechanism and a connecting rod, and is fixed to the mobile platform by bolts, so as to realize the bending movement of two degrees of freedom and the up and down movement of one degree of freedom of a single joint of the serial robot.

[0009] In order to overcome the shortcomings of the prior art, the present invention proposes a tensegrity structure. The structure mainly includes three flexible cables, which connect the tail ends of the heterosexual connecting rods of the mobile platform and the cable fixer to achieve support between the platforms of the serial robot, and meet the rigidity and lightweight requirements of the serial robot under the premise of ensuring support.

[0010] As a further improvement of the above scheme, in this scheme, the mobile platform is connected through a tensegrity structure, and is connected in the order of mobile platform-tensegrity structure-mobile platform to form the main frame of the serial robot.

[0011] As a further improvement of the above scheme, the present invention designs a flexible joint mechanism, which is composed of three tetrahedrons of different sizes stacked together to reduce the wear of bending movement and provide torque to connect the flexible bending part with the support rod to form a complete flexible joint.

[0012] As a further improvement of the above scheme, the flexible joint mechanism is fixed to the middle layer of the mobile platform so that the mobile platform and the flexible joint mechanism are rigidly connected to ensure that the distal rotation point of the flexible joint and the cable fixer at the top of the mobile platform are in the same plane. This design aims to ensure the bending movement of the serial robot and assist the serial robot in the bent state to return to its initial state, thereby reducing the power consumption of the motor.

[0013] As a further improvement of the above-mentioned scheme, the lower layer of the mobile platform of the present invention is used to fix the driving cable and the tensioned overall structure, and the driving cable holes are arranged, and the driving cable holes and the special-shaped connecting rods are evenly distributed on the circular ring in a cross manner to ensure the uniformity of force distribution, thereby increasing the force transmission efficiency and improving the control of the serial robot's posture.

[0014] As a further improvement of the above scheme, the present invention combines the mobile platform, the flexible joint mechanism and the tensegrity structure into a single bending joint mechanism of the serial robot. The end effector and the bending joint mechanism of the cable-driven serial robot control the bending motion by driving the cable. Through the forward and reverse rotation of the motor, the spatial motion of the single joint with three degrees of freedom can be achieved.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The innovative mobile platform realizes different functional roles, reduces the mass of the mobile platform while ensuring rigidity, and replaces the role of the traditional serial robot connecting rod. 2. The flexible joint mechanism and the overall tension structure are used to improve the bending compliance of the serial robot. Compared with the spring, on the basis of achieving flexible bending, the stability of the bending is guaranteed, and the mass of the main structure of the serial robot is greatly reduced, and the posture control of the serial robot is enhanced. 3. The driving cable is made of a material that cannot be axially deformed, and three cables are used. Compared with the serial robot controlled by four cables, the structure is simple and the cost is reduced. At the same time, the drive redundancy is reduced, the control strategy is simplified, and the range of the workspace is greatly improved. 4. The overall tension structure and modular design are adopted to improve the load capacity while reducing the weight, and take into account the flexibility and anti-deformation ability of the robot.

[0016] Key points of the present invention:

[0017] 1. This design is a serial robot with the advantages of light weight, modularity, easy control, and safe interaction with the human body.

[0018] 2. The innovatively designed three-dimensional mobile platform can achieve multiple functions while ensuring rigidity.

[0019] 3. The flexible joint mechanism and the overall tension structure are used as the main body of the serial robot to ensure the bending compliance of the serial robot, while having good elastic deformation and not easy to be damaged.

[0020] 4. Driven by flexible cables, three driving flexible cables are used to control a single bending joint mechanism to achieve three-degree-of-freedom spatial motion. The module structure is simplified, redundancy in motion is reduced, and the flexibility of the serial robot is improved.

[0021] 5. The main serial structure of the present invention adopts a sandwich modular structure of a flexible joint mechanism-tensile integral structure-mobile platform to ensure the stability of the serial robot during bending movement. The lightweight tensile integral structure supports the gravity exerted on the bending joint, and the flexible joint mechanism provides bending compliance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an overall structural diagram of a serial robot according to a specific embodiment of the present invention;

[0023] Figure 2 It is a connection diagram of a mobile platform, a tensegrity structure, and a flexible joint mechanism in a specific embodiment of the present invention;

[0024] Figure 3 is a perspective view of a mobile platform in a specific embodiment of the present invention;

[0025] Figure 4 is a perspective view of a flexible joint mechanism in a specific embodiment of the present invention;

[0026] Figure 5 is a perspective view of a fixed platform in a specific embodiment of the present invention;

[0027] Figure 6 is a perspective view of a flexible cable drive device according to a specific embodiment of the present invention;

[0028] Figure 7 is a perspective view of a basic frame platform in a specific embodiment of the present invention; DETAILED DESCRIPTION

[0029] The following is combined with Figure 1 -Attached Figure 7 The present invention is further described in detail with reference to the specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Reference Figure 1A novel flexible cable-driven serial robot based on flexible joints and tension structures, characterized in that it includes a mobile platform (11000), a flexible joint mechanism (12000), a driving flexible cable (13000), a tensioned integral structure (14000), a fixed platform (15000), a driving motor mechanism (16000) and a robot operating platform (17000). At the bottom joint of the serial robot, the tensioned integral structure (14000) is assembled on the cable fixing support rod of the fixed platform (15000) and the lower end of the heterogeneous connecting rod of the mobile platform (11000). The mobile platform (11000) is connected to the fixed platform (15000) by using the tensioned integral structure (14000) and the flexible joint mechanism (12000). The connection between the mobile platforms (11000) above uses the tensioned integral structure (14000) and the flexible joint mechanism (12000) as the connecting part to realize the assembly of the serial robot as a whole.

[0031] Reference Figure 2 The mobile platform (11000) serves as the main frame of the serial robot (10000). The specific connection method is as follows: Figure 2 As shown, the mobile platform (11000) is assembled by bolting four parts, the lower end of the special-shaped connecting rod in the mobile platform (11000) is used to fix one end of the tensegrity structure (14000), and the other end is connected to the cable fixer of the next mobile platform (11000), the middle fixed flexible joint mechanism (12000) of the mobile platform (11000) is responsible for installing the flexible joint, and the support rod of the flexible joint mechanism (12000) is connected to the upper ring of the lower layer of the upper mobile platform (11000). The tensegrity structure (14000) is mainly responsible for supporting the gravity of the mobile platform (11000) and taking into account the flexibility and rigidity of the robot, and the flexible joint mechanism (12000) is responsible for providing the restoring torque of the serial robot (10000) at different deformations, as well as the stability of bending during movement.

[0032] Reference Figure 3The mobile platform (11000) includes four parts, which are divided from top to bottom, namely, a cable fixer (11001), a fixed flexible joint mechanism platform (11002), a fixed driving flexible cable and a ring (11003) for tensegrity structure, and a special-shaped connecting rod (11004). The cable fixer (11001) is connected to the special-shaped connecting rod (11004) by bolts, and the special-shaped connecting rod (11004) has a corresponding bayonet, which is also connected to the fixed flexible joint mechanism platform (11002) and the fixed driving flexible cable and the ring (11003) for tensegrity structure by bolts. The circular ring (11003) for fixing the driving cable and the tensegrity structure has corresponding installation positions for the flexible joint support rods and fixing holes for the driving cable (13000). The ends of the cable fixers (11001) and the special-shaped connecting rods (11004) of the mobile platform (11000) are used to fix the tensegrity structure (14000). The two ends of the tensegrity structure (14000) are responsible for connecting the two mobile platforms (11000) in series.

[0033] Reference Figure 4 The flexible joint mechanism (12000) is a flexible bending structure (12001) of which is composed of three triangular prisms of different sizes stacked together, and is connected to two upper and lower mobile platforms (11000) in series through a tail support rod (12002) and a base. The cross-section of the flexible bending structure (12001) in the flexible joint mechanism (12000) is triangular. Each face of the flexible bending structure (12001) intersects at a point in the extended space and rotates around the point. The tail support rod (12002) is fixed to the flexible bending structure (12001) in a spiral manner, and the end of the tail support rod (12002) is fixed to the ring (11003) at the lower layer of the mobile platform (11000), and the bottom end of the flexible bending structure (12001) is fixed to the platform (11002) at the middle layer of the mobile platform (11000).

[0034] Reference Figure 5 , is a fixed platform (15000) in a specific embodiment of the present invention, which is composed of a cable-fixed support rod (15001) and a bottom disc (15002). As the base of the entire serial robot, it needs to bear the gravity of the entire serial robot (10000). The middle cable-fixed support rod (15001) is installed upward from the bottom disc (15002) and is fixed to the bottom disc (15002) by bolts. The bottom disc (15002) has reserved holes for assembling the flexible joint mechanism (12000) and driving the movement of the flexible cable (13000).

[0035] Reference Figure 6, is a driving motor mechanism (16000) in a specific embodiment of the present invention. The driving motor mechanism (16000) is mainly divided into five parts, namely a driving motor bracket (16001), a driving flexible cable V-shaped wheel (16002), a transmission shaft (16003), an elastic coupling (16004) and a servo driving motor (16005). The servo driving motor (16005) is installed on the driving motor bracket (16001), and the two sides of the driving motor bracket (16001) are fastened with bolts. The transmission shaft (1600 3) passing through the driving motor bracket (16001), and connecting the rotating shaft of the servo driving motor (16005) with the transmission shaft (16003) by means of an elastic coupling (16004), and installing a driving flexible cable V-shaped wheel (16002) on the transmission shaft (16003), and fastening the driving flexible cable V-shaped wheel (16002) to the transmission shaft (16003) by means of bolts, and applying lubricating oil on the contact surface between the transmission shaft (16003) and the driving motor bracket (16001) to reduce the friction when the transmission shaft (16003) rotates.

[0036] Reference Figure 7 , which is a robot operating platform (17000) in a specific embodiment of the present invention, all the components of the serial robot and the driving motor mechanism (16000) are assembled on the robot operating platform (17000), and the fixing platform (15000) and the driving motor mechanism (16000) are connected to the robot operating platform (17000) with bolts to prevent relative displacement during movement, and at the same time, the positions are evenly distributed in a certain order to ensure the stability of the serial robot movement.

Claims

1. A cable-driven serial robot based on flexible joints and tensioning structures, characterized in that: It includes a mobile platform, a fixed platform, a flexible joint mechanism, a tensegrity structure and a flexible cable driving device. The flexible joint mechanism includes a flexible joint arranged between the mobile platform and the fixed platform, and a flexible joint arranged between the mobile platform and the mobile platform. The tensegrity structure includes a flexible cable arranged between the mobile platform and the fixed platform, and a flexible cable arranged between the mobile platform and the mobile platform. The flexible cable driving device is driven by a reduction drive, and the flexible cables are arranged in the order of mobile platform-mobile platform-mobile platform-fixed platform-motor.

2. According to claim 1, a cable-driven serial robot based on a flexible joint and a tensioning structure is characterized in that: The fixed platform is manufactured in one piece and consists of two layers of platforms, the upper layer is used to fix the flexible joint, and the lower layer is used to fix the tension structure.

3. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: The flexible joint mechanism is composed of three flexible joints forming a group, and the three flexible joints are arranged in a circle with an angle of 120° between each other.

4. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: The flexible joint in the flexible joint mechanism is manufactured in one piece and is a modular spherical flexible joint composed of three triangular prism units.

5. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: Each group of tensegrity in the tensegrity structure is connected by three groups of flexible cables.

6. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: In the tensegrity structure, the bottom of the mobile platform and the top of the fixed platform form a tensegrity, and the bottom of the mobile platform and the top of the mobile platform form a tensegrity.

7. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: The three groups of flexible cables in the flexible cable driving device are connected in series with the movable platform and the fixed platform.

8. The cable-driven serial robot based on flexible joints and tensioning structure according to claim 1, characterized in that: The flexible cable driving device drives three groups of flexible cables respectively through three groups of drivers.

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