Disclosure of Invention
The invention aims to solve the technical problems:
(1) The intermediate value of the load applied to the mechanical joint is not 0, so that the driving mechanism is large in shape selection, and the load capacity of the joint is reduced;
(2) To solve the above problem (1), the elastic element is added to counteract part of the load moment, but the introduction of the elastic element brings an additional moment, which cannot be collected in the conventional feedback system, and thus cannot be controlled by the control system.
The invention provides an integrated joint mechanism meeting the requirements, which comprises the following specific technical scheme:
An integrated joint with elastic moment compensation element, comprising:
the motor comprises a motor stator, a motor rotor and a motor output shaft;
The reduction gearbox comprises a reduction gearbox shell, a reduction gearbox input shaft and a reduction gearbox output shaft; the motor comprises a motor stator, a motor rotor, a motor shell, a motor rotor, a motor input shaft and a motor input shaft, wherein the motor shell is fixedly connected with the motor stator; an output shaft of the reduction gearbox is connected with a load through a torque sensor, and macroscopic relative movement does not exist between the load and the output shaft;
The angle encoder consists of a fixed disc and a movable disc; wherein, the fixed disk is connected with the motor stator, and the movable disk is connected with the motor rotor;
the first end of the elastic element is connected with the shell of the reduction gearbox, and the second end of the elastic element is connected with the output shaft of the reduction gearbox;
the torque sensor is arranged between the output shaft of the reduction gearbox and the load and is connected with the output shaft of the reduction gearbox and the load, so that macroscopic relative movement does not exist between the output shaft of the reduction gearbox and the load;
And the control system is used for receiving the measurement data of the angle encoder and the moment sensor and controlling the joint.
Further, the control system comprises a moment estimation module for the elastic element; the moment estimating module takes the measured data of the angle encoder as input, calculates the influence on the joint system after the elastic element is introduced according to the mechanical characteristics of the joint, and outputs the influence to the moment control module of the control system.
Further, the elastic element generates a predicted moment and partially or completely counteracts the load moment of the joint during the movement of the joint. The elastic element outputs the estimated moment by utilizing the self-recoverable elastic deformation. Elastic deformation refers to stretching, compression, torsion or bending.
Further, the elastic element is selected from one or more of spiral spring, spiral spring and rubber band.
Further, the elastic element is a spiral spring. The scroll spring controls the pre-tightening degree by a locking assembly, and the locking assembly consists of a fixed locking block and a sliding locking block; the sliding locking block is slidably arranged on the reduction gearbox shell and limits the relative movement of the first end of the scroll spring and the reduction gearbox shell; the sliding locking block and the reduction gearbox shell slide relatively, so that the scroll spring is driven to be pre-tensioned; the fixed locking block is fixedly arranged on the output shaft of the reduction gearbox and limits the relative movement of the second end of the scroll spring and the output shaft of the reduction gearbox.
Further, a mounting groove for accommodating the spiral spring is provided on a side edge of the reduction gearbox output shaft.
Further, the reduction gearbox housing simultaneously serves as a means for securing the stator of the motor.
The invention has the beneficial effects that:
(1) The torque intermediate value output by the motor and the reduction gearbox is 0, so that the utilization rate of transmission mechanisms such as the motor, the reduction gearbox and the like is improved, and a larger effective working torque can be output by using a smaller motor and the reduction gearbox;
(2) The elastic element is used for compensation, the closing capacity is improved, and meanwhile, the elastic element is additionally arranged between the output shaft of the reduction gearbox and the shell, so that the joint structure is compact, and an integrated joint is formed;
(3) Because of the compact structure, the torque sensor can be arranged behind the joint output end compensated by the elastic element, so that the actual output torque of the joint can be fed back, and the torque, the position and the speed of the integrated joint, the force position and the force position speed can be controlled;
(4) The combination is flexible, and the mechanical legs are combined by connecting rods and integrated joints, so that the mechanical legs and a traveling system are simpler and more convenient to construct and control.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the drawings of the present invention are in simplified form and are not to scale precisely, but rather are merely intended to facilitate a clear and concise description of embodiments of the present invention.
In the description of the present invention, it should be understood that the terms "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
The joint refers to a driving device for driving mechanical legs to move, and a motor and a transmission mechanism are arranged on the joint.
As shown in fig. 8, in the structure of the force control joint in the prior art, the motor is a power input device, after the output torque of the motor is amplified by the reduction gearbox, the motor acts on a load, the magnitude of the output torque of the reduction gearbox is fed back to the control system through the torque sensor, the rotation angle of the motor is fed back to the control system through the angle encoder, and the control amount of the motor is given by the system by calculating the difference between the torque and the position of the target and the feedback reading value, so that the motor moves with proper output torque and rotation speed, and the rotation angle of the motor is as close to the target value as possible; as previously mentioned, such systems do not make efficient use of their motor and reduction gearbox capabilities.
As shown in fig. 9, in order to improve the system to which the elastic compensation element is added, an elastic element is added in addition to the torque sensor. The torque generated by the elastic element cannot be fed back through the torque sensor, so that an effective closed loop cannot be formed, and although the mechanism can realize more efficient utilization of the motor and the reduction gearbox, the mechanism cannot be controlled accurately.
The system of the invention is shown in fig. 10, and is characterized in that an elastic element is arranged between the output shaft of the reduction gearbox and the shell of the reduction gearbox, and a moment sensor is positioned outside the compensated joint, so that the mechanism is packaged into a whole. Therefore, the torque sensor can effectively collect the torque of the output end of the feedback joint and feed back an accurate torque value to the control system, so that the whole system is controllable.
As shown in fig. 1, is a model of a single degree of freedom joint. The integrated joint comprises a motor, a reduction gearbox, an elastic element, a moment sensor and an angle encoder, and is used for driving a load to move, and the structural details of the integrated joint are shown in fig. 2 and 3. The motor mainly comprises a motor stator 9, a motor rotor 10 and a motor output shaft. The reduction gearbox mainly comprises a reduction gearbox shell 1, a reduction gearbox input shaft 2 and a reduction gearbox output shaft 5.
The elastic element 3 may be selected from various elastic elements including, but not limited to, a spiral spring, a torsion spring, a coil spring, a rubber ring, a rubber band, etc. Preferably, the elastic element 3 is a spiral spring. The scroll spring is controlled by a locking assembly which consists of a fixed locking block and a sliding locking block. The slide lock block is slidably mounted to the reduction gearbox housing 1 and limits the relative movement of the first end of the spiral spring and the reduction gearbox housing 1. The slide lock block can be operated in advance, and slides relatively with the reduction gearbox housing 1, thereby driving the preload of the spiral spring. The fixed locking block is fixedly arranged on the output shaft 5 of the reduction gearbox and limits the relative movement of the second end of the spiral spring and the output shaft 5 of the reduction gearbox. For the stability and safety of the operation of the spiral spring, mounting grooves for receiving the elastic elements are provided on the side edges of the reduction gearbox output shaft 5.
The elastic member may employ a torsion spring as shown in fig. 4. Two ends of the torsion spring 11 are respectively provided with two mounting holes, one end of the torsion spring 11 is fixed on the output shaft 5 of the reduction gearbox through a screw, and the other end is fixed on the spring fixing piece 12, so that the degree of freedom of rotation around the cylinder is released. The spring fixing member 12 is provided with a kidney-shaped hole, and its fixing position is adjusted so as to adjust the pre-tightening amount of the torsion spring 11 within a certain range.
The elastic member may also be a rubber band as shown in fig. 5. The number of the rubber bands is two, namely the rubber band 13 and the rubber band 14, and one end of each rubber band is fixedly connected with the output shaft of the reduction gearbox, as shown in fig. 6. The other ends of the rubber band 13 and the rubber band 14 are respectively connected with the reduction gearbox shell 1 through the same rubber band fixing piece 15. When the gearbox is installed, the rubber band is connected to the gearbox shell 1, the rubber band fixing piece 15 is fixed through screws, the rubber band is pre-tightened according to requirements, the rubber band is stretched, and the stretched rubber band is fixed to the gearbox output shaft 5 through screws, as shown in fig. 7. The moment balance position of the joint output can be adjusted by adjusting the stretching amounts of the rubber band 13 and the rubber band 14.
The motor stator 9 is connected with the reduction gearbox shell 1, does not move relative to each other, and serves as a motion relative fixed reference. The angle encoder consists of a fixed disc and a movable disc, wherein the fixed disc 8 of the angle encoder is connected with the motor stator 9, and the movable disc 7 of the angle encoder is connected with the motor rotor 10 and can rotate along with the motor rotor 10. The motor rotor 10 is integrated with the motor output shaft, connected with the reduction gearbox input shaft 2, and inputs torque for the reduction gearbox. The gearbox input shaft 2, gearbox housing 1 and gearbox output shaft 5 together form a gearbox drive train, which serves to reduce the high rotational speed of the motor to a relatively low rotational speed and to increase the final output torque. The elastic element 3 is respectively connected with the reduction gearbox output shaft 5 and the reduction gearbox shell 1, and along with the articulation, the elastic element 3 is lengthened or shortened, so that a compensation moment is provided, and the middle value of the output moment of the motor end is 0. The connecting rod load 6 is indirectly connected with the reduction gearbox output shaft 5, and a moment sensor 4 is arranged between the reduction gearbox output shaft 5 and the connecting rod load 6, and the moment sensor collects the moment output from the connecting rod load 6 to a joint containing the compensation moment of the elastic element and is used for feeding back the moment actually output by the joint.
The implementation principle and means of the specific construction are as follows:
(1) In order to solve the problem that the moment intermediate value is not 0, an elastic element 3 for compensating moment is arranged between the gearbox shell 1 and the gearbox output shaft 5, the moment generated by the elastic element 3 after being pre-tensioned is offset with the inherent moment of the joint, the moment intermediate value of the gearbox is adjusted to 0, and therefore the moment output intermediate value of the motor is also adjusted to 0, which means that the capacities of the motor and the gearbox can be fully exerted, and the output capacity of the joint is improved;
(2) The moment sensor 4 is additionally arranged at the tail end after moment compensation, so that the moment output by the joint is directly collected, and the moment output by the reduction gearbox is not simply collected by current or other modes. The feedback moment of the spring element 3 is then installed, which takes in the influence of the spring element 3 into the feedback system, making it possible to operate such a mechanism.
In addition to the above principle improvements, the following improvements are also seen in the specific structure:
(1) The joint is structurally integrated to form an integrated joint, the reduction gearbox shell 1 is a fixing device of a motor, and the motor rotating shaft and the reduction gearbox input shaft 2 are integrated, so that the space is saved, and the weight is reduced.
(2) The elastic element 3 is mounted between the gearbox housing 1 and the gearbox output shaft 5, whereas some constructions arrange the elastic element between the machine frame and the load. The joint structure of the invention is more compact, and the structure is not greatly enlarged due to the addition of the elastic element, thereby avoiding the influence on practical use.
(3) The output shaft 5 of the reduction gearbox is provided with a groove, the elastic element 3 is blocked in the groove, adverse axial movement is avoided, and the joint works more reliably.
(4) The integrated joint comprises an angle encoder for collecting the absolute position of the motor, and can be used for indicating the accurate position of the joint and improving the control performance of the joint after calculation.
(5) The joints provide moment feedback, so that the output moment can be controlled.
(6) Alternatively, a control system as shown in fig. 7 is added, and position control, speed control, torque control, position control and speed control of shutdown can be realized. Specifically, the control system comprises a moment estimation module of the elastic element, wherein the moment estimation module takes measured data of the angle encoder as a variable.
The joints have multiple application scenes:
(1) A single joint configuration can be achieved with a single joint.
(2) Mechanical legs constructed entirely from the integrated joints of the present invention. For example, a three-degree-of-freedom mechanical leg built by 3 of the integrated joints disclosed by the invention can realize in-plane motion.
(3) The mechanical leg may be implemented in part by the integrated joint of the present invention and in part by a conventional joint. For example, a 6-degree-of-freedom mechanical leg built from 3 of the disclosed integrated joints and another 3 of the common joints may enable spatial movement.
(4) The robot formed by the constructed mechanical legs can walk independently. For example, a bipedal walking robot using 2 mechanical legs with 6 degrees of freedom as a walking mechanism can walk on various floors.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.