A kind of joint of mechanical arm with rigidity controllableTechnical field
The present invention relates to robot fields, more particularly, to a kind of joint of mechanical arm with rigidity controllable.
Background technique
Mechanical arm is a kind of bionical electromechanical equipment, can simulate manpower movement and be made by changing the pose of target object to realizeIndustry.Large scale equipment, robot, sensor and microoperation field is widely applied.Robot keep in space specified position andPosture, it is necessary to enable its joint to lock under given pose, therefore the joint locking of robot becomes robot mechanism and designsIndispensable part.However, joint of mechanical arm is mostly by shaft come the movement of implementation mechanism, when it stops working, byThe micro relative rotation between two components may be can still result in reasons such as inertia, therefore design one kind that its can be achieved is self-lockingMechanical joint, improve kinematic accuracy be known as challenging project.
Document " medical machine person joint's locking mechanism experimental study based on external friction " proposes a kind of based on external frictionThe locking mechanism of joint of mechanical arm, but due to rubbing for a long time between friction plate and joint, cause coefficient of friction smaller and smaller, locksAbility decline.Chinese patent CN109421040A discloses a kind of six degree of freedom intelligence cooperation robot, including pedestal, severalNode and several connecting rods, the pedestal are fixedly connected with node, are fixedly connected between the node or by the connecting rodConnection, the motor, brake, encoder and retarder are successively set on transmission shaft, one side surface of encoder mounting shellIt is provided with a mounting groove being embedded in for driver, the encoder mounting shell side opposite with mounting groove, which is provided with outside one, connects portion,Furthermore the portion of company with external structure for connecting, and motor mounting shell center has a motor cavity, this motor cavity is close to brake peaceOne end of capping has an inward flange, this support sleeve is set on transmission shaft, this support sleeve is by outer ring portion, ball portion and inner ring portionComposition, the inner ring portion are closely connect with transmission shaft outer surface, and the outer ring portion is contacted with encoder mounting shell inner surfaceConnection.But the patent is still without solving the problems, such as kinematic accuracy.
Summary of the invention
It is an object of the invention to provide a kind of joint of mechanical arm with rigidity controllable, overcome in the prior art structure it is multipleDefect miscellaneous, control is inconvenient, kinematic accuracy is low.
The purpose of the present invention can be achieved through the following technical solutions:
A kind of joint of mechanical arm with rigidity controllable, including upper mounting plate, lower platform and it is connected to upper mounting plate and lower flatThe first movement branched chain and the second movement branched chain between platform,
First movement branched chain include the first revolute pair, the second revolute pair, third revolute pair, the 4th revolute pair,
5th revolute pair and the 6th revolute pair,
Second movement branched chain includes the 7th revolute pair,
6th revolute pair is connected with the upper mounting plate, and first revolute pair is connected with the lower platform, and describedSeven revolute pairs are connected with upper mounting plate and lower platform respectively,
5th revolute pair is connected with the 4th revolute pair and the 6th revolute pair respectively by two connecting rods,
The third revolute pair is connected with the 4th revolute pair and the second revolute pair respectively by even root connecting rod,
Second revolute pair is connected by connecting rod with the first revolute pair.
The axis of first revolute pair, third revolute pair and the 6th revolute pair intersects at a bit, which is located at the 7th turnIt moves on secondary axis extended line.Second revolute pair, the 4th revolute pair, the axis of the 5th revolute pair and the 7th revolute pairAxial space it is parallel.Only when the axis coaxle of two revolute pairs, mechanism can be rotated, when two revolute pair axis notIt can not be rotated when coaxial.
The axis of the third revolute pair and other revolute pair axis are not in same plane.Specifically, the first revolute pair,Third revolute pair, the 6th revolute pair axis not in same plane, space junction is a bit；Second revolute pair, the 4th revolute pair,The axial space of five revolute pairs is parallel.Only when the axis coaxle of two revolute pairs, mechanism can be rotated, and be rotated when twoSecondary axis can not rotate when not coaxial.First revolute pair, third revolute pair, the 6th revolute pair axis intersect at a bit, quiteThe axis of spherical hinge then meets rotation condition with the axis coaxle of the 7th revolute pair of right side under a spherical hinge, original state.Wherein, the second revolute pair, third revolute pair, the 4th revolute pair and the 5th revolute pair constitute a four-bar mechanism, when entire mechanismWhen turning to certain angle, by the drive force added in the second revolute pair, promote the change of third revolute pair axis,To make the axis no longer junction of the first revolute pair, third revolute pair, the 6th revolute pair, it is unsatisfactory for coaxial condition at this time, thisWhen mechanism rigidity become larger, realize the controllable of rigidity, while mechanism is locked.Second joint passes through its angle of rotation of Serve Motor ControlDegree, to improve kinematic accuracy.
Above-mentioned revolute pair can may be flexible hinge for rigid hinge, to guarantee that two connected rod pieces can be aroundHinge axes relatively rotate, two hinges for constituting revolute pair are separately connected a connecting rod.
7th revolute pair is connect with upper mounting plate and lower platform respectively through connecting rod.
Compared with prior art, the present invention passes through the position for changing third revolute pair axis in the first branch, to destroyRotation condition has the advantage that
1, it is controllable to can be realized rigidity: only when the axis coaxle of two revolute pairs, mechanism can be rotated, when twoIt can not be rotated when revolute pair axis difference axis.First revolute pair, third revolute pair, the 6th revolute pair axis intersect at a bit,It is equivalent to a spherical hinge, the pivot center of spherical hinge then meets with the axis coaxle of the 7th revolute pair of right side under original stateRotation condition.Second revolute pair, third revolute pair, the 4th revolute pair and the 5th revolute pair constitute a four-bar mechanism, when entireWhen mechanism turns to certain angle, by the drive force added in the second revolute pair, promote third revolute pair axisChange, to make the axis no longer junction of the first revolute pair, third revolute pair, the 6th revolute pair, is unsatisfactory for coaxial item at this timePart, mechanism rigidity becomes larger at this time, realizes the controllable of rigidity, while mechanism is locked.
2, the purpose that the mechanism under any bending angle no longer rotates may be implemented: only when the axis of two revolute pairsWhen coaxial, mechanism can be rotated, and can not be rotated when two revolute pair axis difference axis.First revolute pair, third revolute pair,The axis of 6th revolute pair intersects at a bit, is equivalent to a spherical hinge, the axis of spherical hinge is with right side the 7th under original stateThe axis coaxle of revolute pair, then meet rotation condition.Second revolute pair, third revolute pair, the 4th revolute pair and the 5th revolute pairA four-bar mechanism is constituted, when entire mechanism turns to certain angle, is driven by the driving force added in the second revolute pairIt is dynamic, promote the change of third revolute pair axis, thus make the first revolute pair, third revolute pair, the 6th revolute pair axis no longerJunction is unsatisfactory for coaxial condition at this time, while mechanism is locked.
3, easy for installation, rotary inertia is small, motor imagination is fast: the present invention in joint structure, be lesser by sizeConnection between rod piece, so the overall dimensions in joint also very little, and be motion control is carried out to it by servo motor, soWith lesser rotary inertia.
Detailed description of the invention
Fig. 1 is the structural diagram of the present invention；
Fig. 2 is the principle of the present invention figure.
In figure, 1- upper mounting plate, 2- lower platform, the 7th revolute pair of 12-, the first revolute pair of 13-, the 6th revolute pair of 14-, 15-Third revolute pair, the second revolute pair of 16-, the 4th revolute pair of 17-, the 5th revolute pair of 18-, 19- first connecting rod, 20- second connecting rod,21- third connecting rod, 22- fourth link, the 5th connecting rod of 23-.
Specific embodiment
The present invention is described in detail combined with specific embodiments below.Following embodiment will be helpful to the technology of this fieldPersonnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that the ordinary skill of this fieldFor personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made.These belong to the present inventionProtection scope.
Embodiment
A kind of joint of mechanical arm with rigidity controllable, structure as shown in Figure 1, include upper mounting plate 1, lower platform 2 andThe first movement branched chain and the second movement branched chain being connected between upper mounting plate and lower platform.
First movement branched chain include the first revolute pair 13, the second revolute pair 16, third revolute pair 15, the 4th revolute pair 17,5th revolute pair 18 and the 6th revolute pair 14；6th revolute pair 14, the 7th revolute pair 12 are connected with upper mounting plate 1, the first revolute pair13, the 7th revolute pair 12 is connected with lower platform 2.Second movement branched chain includes the 5th the 7th revolute pair 16；5th revolute pair 18 is logicalIt crosses first connecting rod 19 to be connected with the first revolute pair 14, the 5th revolute pair 18 is connected by second connecting rod 20 with the 6th revolute pair 17.6th revolute pair 17 is connected by third connecting rod 21 with third revolute pair 15, and third revolute pair 15 passes through fourth link 22 and the 7thRevolute pair 16 is connected, and the 7th revolute pair 16 is connected by the 5th connecting rod 23 with the second revolute pair 13；First revolute pair 13 passes through theFive connecting rods 23 are connected with the second revolute pair 16, and the second revolute pair 16 is connected by fourth link 22 with third revolute pair 15, thirdRevolute pair 15 is connected by third connecting rod 21 with the 4th revolute pair 17, and the 4th revolute pair 17 passes through second connecting rod 20 and the 5th rotationPair 18 is connected, and the 5th revolute pair 18 is connected by first connecting rod with the 6th revolute pair 14；Second movement branched chain includes the 7th rotationIt is secondary；7th revolute pair 12 is separately connected upper mounting plate 1 and lower platform 2 by connecting rod.
The axis of the axis of above-mentioned first revolute pair 13, the axis of third revolute pair 15 and the 6th revolute pair 14 intersects at onePoint, the point are located on the axis extended line of the 7th revolute pair 12.Second revolute pair 16, the 4th revolute pair 17 and the 5th revolute pair118 axis is parallel with the axis of the 7th revolute pair 12, and the axis of third revolute pair 15 is with other revolute pair axis not samePlane.
The working principle of the invention is described as follows in combination with Fig. 2:
When the axis of the first revolute pair 13 in the first movement branched chain, the axis of third revolute pair 15, the 6th revolute pair 14Axis intersect at the revolute pair for being a little equivalent to junction, or be equivalent to a spherical hinge, junction point is again in the 7th revolute pairOn 12 axis extended line, i.e., the axis of the first revolute pair 13, the axis of third revolute pair 15, the 6th revolute pair 14 axis andThe axial space of 7th revolute pair 18, which intersects at, a little meets coaxial condition, so when the rotation of the 7th revolute pair 18, mechanismIt can be rotated around the axis of the 7th revolute pair 18.First revolute pair, third revolute pair, the 6th revolute pair axis intersect at a bit.The pivot center of spherical hinge then meets rotation condition with the axis coaxle of the 7th revolute pair of right side under original state.Second rotationPair 16, third revolute pair 15, the 4th revolute pair 17 and the 5th revolute pair 18 constitute a four-bar mechanism, when entire mechanism turns toWhen certain angle, by the drive force added in the second revolute pair 16, promote the change of 15 axis of third revolute pair, fromAnd make the axis no longer junction of the first revolute pair 13, third revolute pair 15, the 6th revolute pair 14, it is unsatisfactory for coaxial item at this timePart, mechanism rigidity becomes larger at this time, realizes the controllable of rigidity, while mechanism is locked.
After rotating when the second revolute pair 16 in the first movement branched chain passes through motor driven, change third revolute pair 15Axial location, so that the axis of the axis of the axis of the first revolute pair 13, third revolute pair 15, the 6th revolute pair 14 and the 7th turnThe axial space no longer junction of dynamic pair 12, then be unsatisfactory for coaxial condition, so mechanism is no longer able to turn, rigidity increases, and realizesRigidity is controllable.
The above description of the embodiments is intended to facilitate ordinary skill in the art to understand and use the invention.Person skilled in the art obviously easily can make various modifications to these embodiments, and described herein generalPrinciple is applied in other embodiments without having to go through creative labor.Therefore, the present invention is not limited to the above embodiments, abilityField technique personnel announcement according to the present invention, improvement and modification made without departing from the scope of the present invention all should be of the inventionWithin protection scope.