Disclosure of Invention
In order to solve the technical problems in the background art, the invention provides a flexible anti-driving parallel robot and a working method, which can ensure the safety of machines and workers in a working state, and have the characteristics of high rigidity, excellent precision, strong bearing capacity, excellent operation performance and the like, and are mainly used in various places with small industrial production and complex working environment, including the fields of actual carrying, stacking and metal processing of various projects.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a first aspect of the present invention provides a compliant counter-drive parallel robot comprising:
The static platform comprises a base, wherein the base is connected with the middle platform through a straight cylinder, a plurality of driving motors are arranged on the outer side of the circumference of the straight cylinder, and the driving motors are connected with a stepped shaft positioned on the middle platform through a belt transmission mechanism;
The middle platform comprises a bearing seat connected to the upper surface of the support plate, the stepped shaft is movably connected in the bearing seat, the input end of the stepped shaft is connected with the driving motor through the belt transmission mechanism, the output end of the stepped shaft is connected with the proximal end of the driving rod, the distal end of the driving rod is sequentially connected with a Hooke hinge, a driven rod and a spherical hinge which are vertically arranged, the spherical hinge is connected with the edge of the lower bottom surface of the movable platform, and a spring damping mechanism is arranged in the driven rod;
and the movable platform is used for connecting with the actuator.
Further, the stationary platform, the intermediate platform and the movable platform are located on the same axis.
Further, every two driving motors are in a group, a plurality of groups of driving motors are uniformly distributed on the upper surface of the base around the circumference of the straight cylinder, and each driving motor is provided with a corresponding stepped shaft, a driving rod, a hook hinge, a driven rod and a spherical hinge.
Further, the belt transmission mechanism comprises a driving wheel and a driven wheel which are connected through a belt, the driving wheel is connected with the output end of the driving motor, and the driven wheel is connected with the input end of the stepped shaft.
Further, the driving rod comprises a proximal end and a distal end, the proximal end of the driving rod is connected with the output end of the stepped shaft, and the input end of the stepped shaft is connected with the driven wheel.
Further, the Hooke's joint comprises hinge bodies respectively connected with the driving rod and the driven rod, the two groups of hinge bodies are movably connected through universal joints, and universal joint shaft sleeves are arranged on the outer sides of the universal joints.
Further, the driven rod comprises a connecting rod, one end of the connecting rod is sleeved with a spring and positioned in the shell to form a spring damping mechanism, two ends of the spring are provided with baffle plates, the other end of the connecting rod is connected with the spherical hinge, and the shell is connected with the Hooke hinge.
Further, the ball hinge comprises a ball head seat connected with the driven rod, the ball head seat is movably connected with the ball head rod, the ball head rod is connected with the movable platform through a connecting piece, and the ball head rod is provided with a ball head cover plate and a dust cover.
Further, the movable platform comprises an actuator mounting seat and an actuator, and the edge of the lower bottom surface of the actuator mounting seat is connected with a corresponding spherical hinge through a connecting piece.
The second aspect of the invention provides a working method of a compliant counter-drive parallel robot, comprising the following steps:
when the movable platform bears impact, the spring damping mechanism in the driven rod acts to absorb the impact;
When the impact force exceeds the maximum damping effect of the spring damping mechanism in the driven rod, the impact force is sequentially transmitted to the hook joint and the driving rod in a pressure mode, the driving rod drives the stepped shaft to reversely rotate, and the driving motor is driven to reversely rotate through the driving belt pulley, so that reverse driving is realized.
Compared with the prior art, the above technical scheme has the following beneficial effects:
1. The anti-driving structure is formed between the middle platform and the movable platform, so that the robot has better flexibility and can adapt to different physical conditions when interacting with an external environment or human beings. When the impact force exceeds the maximum damping effect of the spring damping mechanism in the driven rod, the impact force is sequentially transmitted to the Hooke hinge and the driving rod in a pressure mode, the driving rod drives the stepped shaft to reversely rotate, and the driving motor is driven to reversely rotate through the driving belt pulley to realize reverse driving. The counter-drive arrangement may reduce or stop the application of force when the robot encounters an obstacle or comes into contact with a person, thereby reducing the risk of injury to the person or equipment. The spring damping mechanism mounted in the driven rod can also reduce the damage to the machine structure and operators when the robot faces the impact.
2. The robot is provided with moment by the driving motor, a traditional speed reducer is abandoned, the transmission and torque increase of the torque are completed by the belt pulley with a certain transmission ratio, the belt pulley has good shock resistance and buffering capacity, mechanical vibration is effectively reduced in the movement process, the movement is more stable, and in addition, the transmission efficiency of the belt pulley transmission system is high, the structure is simple, and the installation and the maintenance are convenient. And the belt has small friction and small relative energy loss in the transmission process.
Detailed Description
The invention will be further described with reference to the drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It should be noted that the terminology herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments in accordance with the invention. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
Term interpretation:
Hooke Joint, also known as a universal hinge or ball hinge, is a mechanical connection component capable of achieving multiple degrees of freedom rotation.
Back-drive robots refer to some kind of inverse characteristic or capability of the robot drive system. In a motor drive system, reverse drivability describes whether the motion can be reversed easily, depending on the efficiency of the drive motion and the overall actuator mechanical resistance. When the robot has reverse driving capability, it may be able to more easily achieve reversal of the motion, or in some cases, drive it by an external force or signal.
For example, when the back driving mode is adopted, the robot is allowed to back drive a mechanical arm or a tool carried by the robot through external operation (such as operation of a doctor), so that finer and more flexible operation is realized.
As described in the background art, under the existing production and manufacturing conditions, the large unsafe interaction force generated by the contact between the robot and the environment is generally reduced by adding a moment sensor or reducing the mechanical impedance of the robot by direct driving, and the moment sensor has relatively high cost.
Therefore, the following embodiment provides a flexible anti-driving parallel robot and a working method, which can ensure the safety of machines and workers in a working state, and has the characteristics of high rigidity, excellent precision, strong bearing capacity, excellent operation performance and the like, and is mainly used in various places with small industrial production and complex working environment, including the fields of actual carrying, stacking and metal processing of various projects.
Embodiment one:
As shown in fig. 1-2, a compliant counter-drive parallel robot includes a stationary platform (lower platform), a middle platform (support platform), and a movable platform (upper platform).
The static platform comprises a base 1, a straight cylinder 2 is arranged in the center of the upper surface of the base 1, a plurality of driving motors 3 are arranged on the outer side of the circumference of the straight cylinder 2, and the driving motors 3 transmit power to a stepped shaft 13 positioned on the middle platform through a transmission belt pulley 4.
The middle platform comprises a bearing seat 6 connected to the upper surface of a support plate 14, a stepped shaft 13 is movably connected to the bearing seat 6 through a bearing 5, the input end of the stepped shaft 13 receives power transmitted by a driving motor 3, the output end of the stepped shaft is connected with the proximal end of a driving rod 12, the distal end of the driving rod 12 is sequentially connected with a Hooke joint 7, a driven rod 8 and a spherical hinge 9, and the spherical hinge 9 is connected with the lower bottom surface of the movable platform through a connecting piece 10.
The movable platform is used for connecting corresponding end execution structures and comprises an actuator 11, and the lower surface of a mounting seat of the actuator 11 is movably connected with the spherical hinge 9 through a connecting piece 10.
As shown in fig. 3, the main structure of the static platform (lower platform) is a base 1, the base 1 is connected with the main structure (support plate 14) of the middle platform (support platform) through a straight cylinder 2, and the moving platform (upper platform) is an actuator 11 and a corresponding mounting seat.
The middle platform (supporting platform) and the movable platform (upper platform) are movably connected through RUS mechanisms formed by the bearing seat 6, the driving rod 12, the hook hinge 7, the driven rod 8 and the spherical hinge 9, and the number of the RUS mechanisms corresponds to that of the driving motor 3. In this embodiment, the straight cylinders 2 are fixedly connected with the center of the base 1, the driving motors 3 are grouped around the straight cylinders 2, 6 driving motors 3 form three groups, are uniformly distributed on the upper surface of the base 1 at 120 degrees, are grouped around the straight cylinders 2 as well as the corresponding bearing seats 6, stepped shafts 13, driving rods 12, hooke hinges 7, driven rods 8 and spherical hinges 9 of the driving motors 3, and are uniformly distributed on the upper surfaces of the respective mounting seats at 120 degrees to form a parallel robot of a 6-RUS mechanism, so that the moving platform and the actuator 11 can bear impacts from various directions.
The RUS mechanism in this embodiment is a mechanism formed by sequentially connecting a revolute pair (Revolute joint) -a hook joint (or referred to as a Universal joint) -a ball joint (SPHERICAL JOINT). The specific structure is shown in fig. 4, the input end of the stepped shaft 13 receives the rotation motion from the driving motor 3 through the driving belt pulley 4, the stepped shaft 13 realizes the rotation motion in the bearing seat 6 through the bearing 5, and the output end of the stepped shaft 13 is connected with the proximal end of the driving rod 12. The far end of the driving rod 12 is connected with the driven rod 8 through the hook joint 7, and the other end of the driven rod 8 is connected with the movable platform through the spherical joint 9. The number of the moving mechanisms between the middle platform (supporting platform) and the movable platform (upper platform) corresponds to that of the driving motor 3, when the movable platform receives impact, a spring in the driven rod 8 can absorb part of the impact, when the impact exceeds the damping capacity of the spring, the driven rod 8 is pressed, the generated linear displacement is transmitted to the far end of the driving rod 12 through the Hooke hinge 7, the far end of the driving rod 12 swings around the near end of the driving rod 12, the near end of the driving rod 12 drives the stepped shaft 13 to rotate, and the stepped shaft 13 drives the driving motor 3 to rotate reversely through the transmission belt pulley 4, so that reverse driving is realized. The process is used for counteracting various impacts, so that the safety of the robot in environment interaction is improved, and the impact direction is uncertain, so that 6 groups of RUS mechanisms are connected in parallel as much as possible to cope with more comprehensive impacts.
In this embodiment, the driving motor 3 is a servo motor, and the driving pulley 4 is a V-shaped pulley with a transmission ratio of 3.
As shown in fig. 5, the output end of the driving motor 3 is connected to a driving pulley 41 of the transmission pulley 4, and the driving pulley 41 is connected to a driven pulley 43 via a belt 42.
As shown in fig. 6, the driven wheel 43 is connected to the input end of the stepped shaft 13, and the output end of the stepped shaft 13 is connected to the proximal end of the driving rod 12.
In this embodiment, the driving motor 3 is connected to the driving wheel 41 by a key, the driven wheel 42 is connected to the stepped shaft 13 by a key, and the stepped shaft 13 is connected to the driving lever 12 by a key.
In this embodiment, the bearing 5 is a NU10000 cylindrical roller bearing.
In this embodiment, the bearing housing 6 is a split bearing housing, and includes a bearing base 61 and a bearing end cover 62.
In this embodiment, the outer side of the stepped shaft 13 is sleeved with a shaft sleeve 131, and the shaft sleeve 131 is connected with the bearing 5.
Every two bearing seats 6 are in one group, and are in one-to-one correspondence with the driving pulleys 4 of the static platform, and the bearings 5 are arranged in the bearing seats 6 and are connected with the stepped shafts 13.
As shown in fig. 7, the hook joint 7 is connected with the driving rod 12 and the driven rod 8, the hook joint 7 comprises hinge bodies 71 respectively connected with the driving rod 12 and the driven rod 8, the two groups of hinge bodies 71 are movably connected through universal joints 73, and universal joint shaft sleeves 72 are arranged outside the universal joints 73.
The driven lever 8 is internally provided with a spring damper mechanism for reducing the impact force. As shown in fig. 8, the driven rod 8 includes a connecting rod 81, one end of the connecting rod 81 is sleeved with a spring 82 and is located in a housing 84, two ends of the spring 82 are provided with baffles 83, the other end of the connecting rod 81 is connected with the spherical hinge 9, and the housing 84 is connected with the hook hinge 7. The spring 82 and the baffle 83 are used for reducing impact on mechanical structure and injury to operators when the actuator 11 is impacted by external load.
The driven rod 8 is connected with the movable platform through the spherical hinge 9, the structure of the spherical hinge 9 is shown in fig. 9, the structure comprises a ball seat 91 connected with the driven rod 8, the ball seat 91 is movably connected with a ball rod 92, the ball rod 92 is connected with the movable platform through a connecting piece 10, and a ball cover plate 93 and a dust cover 94 are arranged on the ball rod 92.
The robot is provided with moment by the driving motor, a traditional speed reducer is abandoned, the transmission and torque increase of the torque are completed by the belt pulley with a certain transmission ratio, the belt pulley has good shock resistance and buffering capacity, mechanical vibration is effectively reduced in the movement process, the movement is more stable, and in addition, the transmission efficiency of the belt pulley transmission system is high, the structure is simple, and the installation and the maintenance are convenient. And the belt has small friction and small relative energy loss in the transmission process. When the belt pulley is impacted, the characteristic that the speed reducer cannot reversely move is changed, the external impact force can be changed into the rotation of the motor, the unloading effect is achieved, and the safety of equipment can be protected.
The robot has better flexibility and can adapt to different physical conditions when interacting with an external environment or human beings. If the robot encounters an obstacle or comes into contact with a person, the application of force may be reduced or stopped with its unique counter-drive configuration, thereby reducing the risk of injury to the person or equipment. The spring damping mechanism mounted in the driven rod can also reduce the damage to the machine structure and operators when the robot faces the impact.
Embodiment two:
A working method of a flexible reverse-drive parallel robot comprises the following steps:
In the normal working process, the driving motor 3 provides power to drive the belt pulley 4 to move, the stepped shaft 13 transmits the power from the belt pulley 4 to the driving rod 12, the driving rod 12 and the hook joint 7 further transmit the power to the driven rod 8, and finally 6 supporting legs cooperate to enable the actuator 11 to complete the preset action.
When the movable platform bears impact, firstly, the force is transferred to the spherical hinge 9, and as the spherical hinge 9 has a multi-degree-of-freedom motion state, the position relation between the spherical head rod 92 and the spherical head seat 91 can be changed when the spherical head rod is pressed, so that the force can be transferred to an internal spring without the requirement that the driven rod 8 keeps a certain position state, and at the moment, a spring damping mechanism in the driven rod 8 plays a role to absorb the impact;
When the impact force exceeds the maximum damping effect of the spring damping mechanism in the driven rod 8, the impact force is sequentially transmitted to the hook joint 7 and the driving rod 12 in a pressure mode, the driving rod 12 drives the stepped shaft 13 to reversely rotate, the driving motor 3 is driven to reversely rotate through the driving belt pulley 4, reverse driving is realized, and finally, the impact received by the outside is reduced and eliminated in a motor rotation mode, so that various impacts are counteracted in the process, and the safety of equipment in abnormal collision is maintained.
The action process of the spring damping mechanism of the driven rod 8 comprises the following steps:
a. The actuator 11 receives load of external environment or accidental collision of operators, so that the movable platform bears pressure;
b. The movable platform drives the connecting rod 81 to move, the connecting rod 81 simultaneously compresses the spring 82, and the baffle 83 limits the displacement of the spring 82, so that damping failure is avoided;
In the compression process of the spring 82, a certain pretightening force is applied to the spring, so that the phenomenon of insufficient shock absorption caused by the weight of an upper mechanism and the weight of the spring is avoided in the working state;
c. the spring 82 is now in compression and returns to its original position when the external impact is removed.
The specific implementation method of the back drive comprises the following steps:
a. the driven rod 8 is again subjected to pressure, the impact force at this time having exceeded the maximum damping effect of the spring;
b. The Hooke's joint 7 receives pressure, and this pressure further transmits driving lever 12, and driving lever 12 drives step shaft 13 reverse rotation, and then drives driving motor 3 through driving pulley 4 and reverses to this process offsets various impact that receive.
The driving motor in the embodiment has two functions, namely, the first function is to provide initial power for the mechanism under normal working conditions, and the second function is to transmit impact force to the driving motor to enable the driving motor to reversely rotate when the driving motor is impacted, so that the impact force is counteracted, and safety is guaranteed.
During the process that the impact force is transmitted to the Hooke's joint and the driving rod in a pressure mode through the driven rod, since the spherical hinge 9 has a multi-degree-of-freedom motion state, the spherical head rod 92 can change the position relation with the spherical head seat 91 when the spherical head rod is stressed, so that the force can be transmitted to the internal spring without the requirement that the driven rod 8 keeps a certain position state, and the impact is absorbed. This embodiment shows the motion state of the mechanism at a certain stage.
The back driving is mainly to convert external impact into reverse rotation of the motor, so that the impact on the whole mechanism is reduced, and the back driving has important significance for maintaining the safety and stability of the mechanism. Meanwhile, for operators, the impact on the actuator is prevented from being transmitted to the operators by the mechanism due to the design of back driving, and the injury to the operators can be effectively reduced. On the other hand, if operators bump into the mechanism carelessly, the whole parallel robot is similar to a large spring through the designed spring damping and back driving mode, so that the damage to human bodies can be effectively reduced.
In summary, the robot has better flexibility and can adapt to different physical conditions when interacting with external environment or human beings. If the robot encounters an obstacle or comes into contact with a person, the application of force may be reduced or stopped with its unique counter-drive configuration, thereby reducing the risk of injury to the person or equipment. The spring damping mechanism mounted in the driven rod can also reduce the damage to the machine structure and operators when the robot faces the impact.
The robot is provided with moment by the driving motor, a traditional speed reducer is abandoned, the transmission and torque increase of the torque are completed by the belt pulley with a certain transmission ratio, the belt pulley has good shock resistance and buffering capacity, mechanical vibration is effectively reduced in the movement process, the movement is more stable, and in addition, the transmission efficiency of the belt pulley transmission system is high, the structure is simple, and the installation and the maintenance are convenient. And the belt has small friction and small relative energy loss in the transmission process. When the belt pulley is impacted, the characteristic that the speed reducer cannot reversely move is changed, the external impact force can be changed into the rotation of the motor, the unloading effect is achieved, and the safety of equipment can be protected.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.