Cooperative logistics transfer robot based on cable driving unit and two-connecting-rod passive rigid arm

Abstract

The invention discloses a cooperative logistics transfer robot based on a cable driving unit and a two-connecting-rod passive rigid arm. The cooperative logistics transfer robot comprises a three-dimensional frame supporting unit, a multi-degree-of-freedom cable driving system, the two-connecting-rod passive rigid constraint arm, a tail end execution complex and a central control and sensing system. A plurality of active cable driving modules of the multi-degree-of-freedom cable driving system are fixed to a three-dimensional frame supporting unit and connected with a tail end execution complex through high-strength flexible ropes, and main driving force and a large-range operation space are provided; one end of the two-connecting-rod passive rigid constraint arm is hinged to the base, the other end of the two-connecting-rod passive rigid constraint arm is connected with the tail end execution complex, a driving motor is not arranged in the arm, and only the angle sensing unit and the variable damping vibration suppression unit are integrated. Through the cooperative operation mode of cable driving active output and rigid arm passive guiding and vibration suppression, the robot not only has the large working space and the high load dead weight ratio of cable driving, but also solves the problems that cable driving is prone to vibration and low in precision through the passive rigid arm, and high-dynamic and high-precision carrying operation under the logistics scene is achieved.

Description

Technical Field

[0001] This invention belongs to the field of industrial automation equipment and intelligent logistics robot technology, specifically relating to a collaborative logistics handling robot based on a cable-driven unit and a two-bar passive rigid arm. Background Technology

[0002] In the modern warehousing and logistics industry, handling robots are key equipment for achieving automation. Current handling robots are mainly traditional rigid serial robotic arms. These robots offer high precision and rigidity, but are heavy and have a low load-to-weight ratio. Cable-driven parallel robots can achieve large-space movement using cable traction. These robots have advantages such as simple structure, large workspace, and high load capacity. However, due to the unidirectional force characteristics and flexibility of the cables, the end effector is prone to residual vibrations that are difficult to eliminate during movement, resulting in poor rigidity and motion accuracy. To overcome the problems of existing technologies, there is an urgent need for an innovative configuration that can retain the advantages of the high dynamic characteristics of cable-driven systems while solving the rigidity and precision issues. Summary of the Invention

[0003] In order to overcome the problems existing in the prior art, the purpose of this invention is to provide a collaborative logistics handling robot based on a cable-driven unit and a two-bar passive rigid arm. It adopts a parallel hybrid configuration of active force output by cable drive and passive guidance by rigid arm. Under the premise of ensuring high dynamic characteristics, the passive rigid arm provides good stiffness and motion accuracy.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A collaborative logistics handling robot based on a cable-driven unit and a two-bar passive rigid arm includes a three-dimensional frame support unit, a multi-degree-of-freedom cable-driven system, a two-bar passive rigid constraint arm, an end effector complex, and a central control and sensing system. The multi-degree-of-freedom cable-driven system comprises several active cable-driven modules and corresponding high-strength flexible cables spatially distributed and installed on the three-dimensional frame support unit. The two-bar passive rigid constraint arm includes a first rigid link and a second rigid link, which are connected in series through a passive joint. The proximal end is hinged to the base or the ground, and the distal end extends into the workspace and connects to the end effector complex. The passive joint integrates an angle sensing unit and a variable damping vibration suppression unit, but does not include an active drive motor. The end effector complex is simultaneously connected to the end of the high-strength flexible cable and the distal end of the two-bar passive rigid constraint arm. The multi-degree-of-freedom cable-driven system retracts and extends the high-strength flexible cable to drive the end effector complex to move, and the two-bar passive rigid constraint arm follows to provide kinematic constraints, real-time posture feedback, and radial stiffness support.

[0005] The multi-degree-of-freedom cable-driven system includes at least three sets of active cable-driven modules, each set of modules being evenly distributed on the top beam or column of the three-dimensional frame support unit, forming a parallel drive topology. This multi-degree-of-freedom cable-driven system is the sole power source, responsible for driving the translation and rotation of the end effector complex in space.

[0006] The joint configuration of the two-link passive rigid constraint arm is as follows: a three-degree-of-freedom ball-and-socket joint or orthogonal rotary joint group is provided between the first rigid link and the base; a single-degree-of-freedom or double-degree-of-freedom elbow joint, i.e., a passive joint, is provided between the first rigid link and the second rigid link; a three-degree-of-freedom wrist joint is provided between the second rigid link and the end effector complex; this configuration is used to ensure the accessibility of the end effector complex in the workspace and limit its uncontrolled spin around the axis of the high-strength flexible rope.

[0007] Preferably, the joint configuration of the two-link passive rigid constraint arm is as follows: a three-degree-of-freedom ball-and-socket joint or orthogonal rotary joint group is provided between the first rigid link and the base; a single-degree-of-freedom or two-degree-of-freedom elbow joint, i.e., a passive joint, is provided between the first rigid link and the second rigid link; a three-degree-of-freedom wrist joint is provided between the second rigid link and the end effector complex. This configuration is used to ensure the accessibility of the end effector complex in the workspace and limit its uncontrolled spin around the axis of the high-strength flexible rope, ensuring the overall rigidity of the robot system while providing good dynamic characteristics.

[0008] The central control and sensing system adjusts the torque and speed of the servo motors in each active cable drive module, and coordinates the length and internal tension of each high-strength flexible rope, so that the end effector complex can obtain controlled motion capability of at least three translational degrees of freedom out of the six spatial degrees of freedom.

[0009] Preferably, the central control and sensing system collects data from the angle sensing unit in real time, calculates the actual pose of the end effector complex through forward kinematics, compares it with the target trajectory, and then uses the Jacobian matrix to inversely solve for the tension correction commands of each high-strength flexible rope, thereby achieving closed-loop control.

[0010] Preferably, the variable damping vibration suppression unit is a magnetorheological damper or a rotational viscous damper, used to provide variable damping torque when the end-effector stops or positions the complex at high speed, thereby suppressing residual vibration.

[0011] Preferably, the high-strength flexible rope is made of multi-strand twisted tungsten wire rope or ultra-high molecular weight polyethylene fiber rope to improve the service life of the rope.

[0012] The aforementioned logistics handling robot is powered by a multi-degree-of-freedom cable drive system that provides the force and torque required for motion. A two-link passive rigid constraint arm follows the motion, and the rigid link restricts the degree of freedom of the end effector complex, increasing the radial stiffness of the system. The end effector pose is directly calculated by the joint encoder, providing more accurate position feedback. At the same time, the vibration energy of the cable system is absorbed by the variable damping vibration suppression unit.

[0013] Compared with the prior art, the present invention has the following advantages: Because the rigid arm has no motor, its moment of inertia is extremely low, significantly superior to traditional heavy-duty robotic arms. Furthermore, compared to purely cable-driven robots, the passive rigid arm provides additional geometric constraints and radial stiffness, effectively suppressing load sway. It also directly measures pose through link angles, eliminating positioning errors caused by cable elasticity. The variable damping vibration suppression unit integrated within the joint can quickly attenuate residual vibrations generated during high-speed handling. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a collaborative logistics handling robot based on a cable-driven unit and a passive rigid arm according to the present invention.

[0015] Figure 2 This is a schematic diagram of the active cable drive module of the collaborative logistics handling robot based on the cable drive unit and passive rigid arm of the present invention.

[0016] Figure 3 This is a schematic diagram of the two-link passive rigid arm of the collaborative logistics handling robot based on the cable-driven unit and the passive rigid arm of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, this embodiment proposes a collaborative logistics handling robot based on a cable-driven unit and a two-bar passive rigid arm. Its main structure includes: a three-dimensional frame support unit 100, a multi-degree-of-freedom cable-driven system 200, a two-bar passive rigid constraint arm 300, an end effector complex 400, and a central control and sensing system 500.

[0019] In this embodiment, the three-dimensional frame support unit 100 is installed on the ground in the logistics warehousing environment. It is a gantry structure that spans the conveyor belt and shelves, and is responsible for providing support for the entire robot system and defining the robot's workspace. The multi-degree-of-freedom cable drive system 200 is installed on the three-dimensional frame support unit 100. The proximal end of the two-link passive rigid constraint arm 300 is installed at the center of the ground, and the distal end extends into the interior of the three-dimensional frame support unit 100. The end effector complex 400 is connected to both the end of the primary drive rope 220 of the multi-degree-of-freedom cable drive system 200 and the distal end of the two-link passive rigid constraint arm 300.

[0020] like Figure 1 and Figure 2 As shown, the multi-degree-of-freedom cable drive system 200 consists of an active cable drive module 210 and a high-strength flexible rope 220 driven by the active cable drive module 210. In this embodiment, three sets of active cable drive modules 210 are arranged and spatially distributed on the top of the three-dimensional frame support unit 100, forming an equilateral triangle distribution and a parallel drive topology.

[0021] like Figure 2 As shown, the active cable drive module 210 includes a servo drive motor, a reducer, and a drum, which is responsible for controlling the winding and unwinding of the high-strength flexible rope 220, thereby driving the movement of the end effector 400. The high-strength flexible rope 220 is controlled by the active cable drive module 210 for winding and unwinding. After being led out from the drum, it is finally connected to the end effector 400. In this embodiment, the high-strength flexible rope 220 is made of multi-strand twisted tungsten wire rope to improve the service life of the rope and reduce elastic deformation.

[0022] like Figure 3 As shown, the two-link passive rigid constraint arm 300 includes a first rigid link 310, a second rigid link 320, a passive joint 350, an angle sensing unit 330, and a variable damping vibration suppression unit 340. The two-link passive rigid constraint arm 300 has no internal motor, reducer, or drive shaft. The first rigid link 310 and the second rigid link 320 are manufactured using lightweight carbon fiber material to minimize follow-up inertia.

[0023] The joint configuration of the two-link passive rigid constraint arm 300 is as follows: a three-degree-of-freedom ball-and-socket joint or orthogonal rotary joint group is provided between the first rigid link 310 and the base; a single-degree-of-freedom elbow joint, i.e., a passive joint 350, is provided between the first rigid link 310 and the second rigid link 320; and a three-degree-of-freedom wrist joint is provided between the second rigid link 320 and the end effector 400. This configuration is used to ensure the accessibility of the end effector 400 within the workspace and to limit its uncontrolled spin around the cable axis. The passive joint 350 integrates an angle sensing unit 330 and a variable damping vibration suppression unit 340, but does not include an active drive motor. The angle sensing unit 330 is responsible for collecting the angle data of each joint in real time; in this embodiment, the variable damping vibration suppression unit 340 uses a rotary magnetorheological damper, which is responsible for providing variable damping torque under specific working conditions.

[0024] When performing logistics handling operations, the robot's motion consists of two parts: the active driving motion of the multi-degree-of-freedom cable drive system 200 and the passive follow-up motion of the two-link passive rigid constraint arm 300.

[0025] First, the central control and sensing system 500 adjusts the torque and speed of the servo drive motors in each active cable drive module 210, coordinating the length and internal tension of the four high-strength flexible ropes 220, and drives the end effector complex 400 to move towards the target cargo position. At this time, the two-link passive rigid constraint arm 300 is passively deployed or folded under the traction of the end effector, following the movement to provide kinematic constraints and radial stiffness support, preventing load swaying.

[0026] During the movement, the central control and sensing system 500 collects data in real time from the angle sensing unit 330 on the two-link passive rigid constraint arm 300, calculates the actual pose of the end effector complex 400 through forward kinematics, and compares it with the target trajectory. If there are errors caused by the elasticity of the high-strength flexible ropes, the robot system uses the Jacobian matrix inverse solution to obtain the tension correction commands for each high-strength flexible rope, dynamically adjusts the output of the active cable drive module 210, realizes closed-loop control, and ensures grasping accuracy.

[0027] When the end-effector 400 reaches the designated position for high-speed stopping or positioning and grabbing, residual vibration is prone to occur due to the under-constraint characteristics of the high-strength flexible rope. At this time, the central control and sensing system 500 controls the variable damping vibration suppression unit 340 to work, adjusting the current of the variable damping vibration suppression unit 340 to increase joint damping and provide a reverse torque to quickly suppress the residual vibration of the end-effector 400, achieving stable placement of goods. Through the linkage of the high-torque drive of the multi-degree-of-freedom cable drive system 200 and the geometric constraints and vibration suppression characteristics of the two-link passive rigid constraint arm 300, a balance between high efficiency and precision is ultimately achieved in large-space logistics handling operations.

[0028] It is worth noting that although the technical solutions and preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the specific embodiments described above. The embodiments described above are merely illustrative. Those skilled in the art can make many other forms based on the inspiration of the present invention without departing from the spirit and scope of the claims, and these all fall within the scope of protection of the present invention.

Claims

1. A collaborative logistics handling robot based on a combination of a cable-driven unit and a two-link passive rigid arm, characterized in that: The application relates to a multi-freedom cable-driven robot, which comprises a three-dimensional frame support unit, a multi-freedom cable-driven system, a two-link passive rigid constraint arm, an end execution complex and a central control and sensing system; the multi-freedom cable-driven system comprises a plurality of active cable-driven modules and corresponding high-strength flexible ropes which are installed on the three-dimensional frame support unit in a spatial distribution; the two-link passive rigid constraint arm comprises a first rigid link and a second rigid link which are connected in series through a passive joint, the proximal end of the two-link passive rigid constraint arm is hinged to a base or the ground, and the distal end of the two-link passive rigid constraint arm extends to the inside of a working space and is connected with the end execution complex; the passive joint is internally integrated with an angle sensing unit and a variable-damping vibration suppression unit, and does not contain an active driving motor; the end execution complex is connected with the distal end of the high-strength flexible rope and the distal end of the two-link passive rigid constraint arm; the high-strength flexible rope is retracted and released through the multi-freedom cable-driven system to drive the end execution complex to move, and the two-link passive rigid constraint arm follows to provide kinematic constraint, real-time pose feedback and radial rigidity support.

2. The logistics handling robot according to claim 1, characterized in that, The multi-freedom cable-driven system comprises at least three groups of active cable-driven modules, each group of modules is arranged on the top beam or the upper end of a stand of the three-dimensional frame support unit, and constitutes a parallel driving topological structure.

3. The logistics handling robot according to claim 1, characterized in that, The joint configuration of the two-link passive rigid constraint arm is as follows: a three-freedom ball-and-socket joint or an orthogonal rotary joint group is arranged between the first rigid link and the base; a single-freedom or double-freedom elbow joint, i.e. a passive joint, is arranged between the first rigid link and the second rigid link; and a three-freedom wrist joint is arranged between the second rigid link and the end execution complex; the configuration is used for ensuring the accessibility of the end execution complex in the working space and limiting the uncontrollable self-rotation of the end execution complex around the axis of the high-strength flexible rope.

4. The logistics handling robot according to claim 3, characterized in that, The two-link passive rigid constraint arm is internally free of motors, reducers and transmission shafts, and is made of light-weight materials to minimize the following inertia.

5. The logistics handling robot according to claim 1, characterized in that, The central control and sensing system adjusts the torque and rotating speed of the servo motor in each active cable-driven module, coordinates the length and internal tension of each high-strength flexible rope, and enables the end execution complex to have a controlled motion ability of at least three translational degrees of freedom in six spatial degrees of freedom.

6. The logistics handling robot according to claim 1, characterized in that, The central control and sensing system collects the data of the angle sensing unit in real time, calculates the actual pose of the end execution complex through forward kinematics, compares the actual pose with a target trajectory, and then inversely solves the tension correction instructions of each high-strength flexible rope through a Jacobian matrix to realize closed-loop control.

7. The logistics handling robot according to claim 1, characterized in that, The variable-damping vibration suppression unit is a magneto-rheological damper or a rotary viscous damper, which is used for providing a variable damping torque to suppress residual vibration when the end execution complex is high-speed stopped or positioned.

8. The logistics handling robot according to claim 1, characterized in that, The high-strength flexible rope adopts a multi-strand twisted tungsten wire rope or an ultra-high molecular weight polyethylene fiber rope to improve the service life of the rope.

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