A kind of flexible joint that mixes control
Technical field
The present invention relates to Robotics field, be specifically related to a kind of flexible joint that mixes control.
Background technology
Through the development of nearly 60 years, comparative maturity of the technology of industrial robot, and be widely used in various fields.But the intelligent degree of industrial robot is on the low side at present, in actual industrial production, the necessary physical isolation of industrial robot and operating personnel, can guarantee like this personal safety of operating personnel in production process, but cannot improve operating efficiency by man-machine collaboration, hinder industrial robot applying in medium-sized and small enterprises and high-end assembling.In recent years, take KUKA, ABB and BAXTER as the company of robot of representative, based oneself upon the research and development of brand-new generation industrial robot interactive mode, man-machine collaboration has become the intelligentized target of industrial robot of new generation and representative.Therefore, improve the intelligent level of robot, realize the security that machine person to person assists, the development of China's Robot industry is had to important strategic importance.
Design a kind of flexible joint with biddability and be hoisting machine people intelligent level and realize the mutual physical basis of man-machine safety.Nineteen ninety-five, the people such as Gill Pratt publish thesis " Series Elastic Actuator " (series connection elastic driving joint) afterwards, the spring of connecting between actuator output and load has been proposed, by detecting both rotational angles poor (or alternate position spike), be multiplied by the coefficient of elasticity of spring, just can obtain being applied to the moment in load, this mode has realized the Torque Control in joint preferably.Wherein, the spring of series connection can also be served as the wave filter of resisting external impact, therefore in the time resisting external impact, has certain advantage.This series connection elastic joint has obtained application in the biped robot in MIT laboratory and six degree of freedom mechanical arm.
After 20 years, in the time that people start again sight to focus on flexible joint, need to face two problems: the first, need to detect the differential seat angle at two positions due to series elastic driver, conventionally can adopt two angular transducers, make structural design more complicated, cost is higher; The second, the location track that realizes joint by control or moment is followed the tracks of, and this control when thering is no serial spring is much more difficult.
The patent documentation that is CN102632509A as application publication number discloses a kind of flexible drive modularized joint with force feedback control, it comprises joint transmission means and force signal checkout gear two parts, and wherein force signal checkout gear is made up of elasticity torsion spring, the first absolute type angular transducer and the second absolute type angular transducer; The first absolute type angular transducer is made up of the first rotor and the first stator, the first rotor is fixed on output shaft by wave washer and jump ring, the first stator is fixed on the shell of joint through installing tache, the second absolute type angular transducer is made up of the second rotor and the second stator, the second rotor is fixed on output by end cap flange and covers, and the second stator is fixed on the flange of joint through sleeve.Can measure the differential seat angle of elasticity torsion spring by two absolute type angular transducers, but this can make structural design more complicated, cost is higher; And elasticity torsion spring does not have stopping means, if moment of torsion exceeds limited range, can cause torsion spring excessively to reverse, affect greatly the precision of measuring.
Summary of the invention
For the problems referred to above, the invention provides a kind of flexible joint that mixes control.This flexible joint combines the demand of practical application, has solved that the design of existing flexible joint is complicated, cost is high and there is no the problem of stopping means.
The technical scheme that the present invention takes is as follows:
A flexible joint that mixes control, comprising:
With the motor of harmonic wave drive speed reducer;
The torsion spring being connected with the output shaft of described harmonic wave drive speed reducer;
The rotating mechanism that driven by described torsion spring;
For testing the measuring mechanism of rotating mechanism moment of torsion;
Described measuring mechanism is by the motor encoder for measuring machine shaft corner, and forms for the absolute type angular transducer of measuring rotating mechanism corner.
Described harmonic wave drive speed reducer comprises wave producer, firm wheel, flexbile gear, and described flexbile gear is connected with output shaft.
Described absolute type angular transducer comprises the rotor sensor and the sensor stator that cooperatively interact, and sensor stator is fixed on electric machine casing, and rotor sensor is fixed on rotating mechanism.
As preferably, described torsion spring comprises:
Outer shroud, is rotatably assorted with the inwall of electric machine casing;
Interior ring, fixes with the output shaft of described harmonic wave drive speed reducer;
Some elastomers, are fixed between outer shroud and interior ring, and described elastomer is uniformly distributed along inner circumference edge, the band shape that elastomer is reciprocal bending.Torsion spring can improve submissive and mechanism stored energy for joint, and the back and forth banded elastomer processing of bending, easy for installation, and in the time that torsion spring inner and outer ring rotates mutually, good reliability, precision are high.
Described rotating mechanism comprises drive plate, and described drive plate and described outer shroud are fixed.Torsion spring drives rotating mechanism by rolling disc.
As preferably, between described outer shroud and interior ring, be provided with the tie-down cable for limiting ultimate angle.Tie-down cable has certain length, and in the time that outer shroud and interior ring turn to certain position, thereby tie-down cable is straightened, restriction outer shroud and interior ring further relatively rotate, and prevents when moment of torsion is excessive torsion spring to produce and destroy, thereby plays the effect of position limitation protection.
As preferably, described inner walls is provided with the limited block extending between outer shroud and interior ring.In the time that outer shroud and interior ring turn to certain position, elastomer contacts with limited block, thereby restriction outer shroud and interior ring further relatively rotate.
As preferably, on described limited block, be arranged with cushion collar.Play cushioning effect, protection elastomer and limited block.
As preferably, machine shaft is the extension that passes electric machine casing away from one end of rotating mechanism;
Described motor encoder comprises:
The first pedestal, interfixes with electric machine casing, and is in the periphery of extension;
The first stator, is fixed on the first pedestal;
The first rotor, is fixed on machine shaft, matches with described the first stator.
As preferably, Hall element is installed on motor stator.This Hall element is for the electric current commutation of motor internal.
The invention has the beneficial effects as follows: by the motor encoder by for measuring machine shaft corner, and obtain the windup-degree of torsion spring for measuring the absolute type angular transducer of rotating mechanism corner, the coefficient of elasticity that windup-degree is multiplied by torsion spring can obtain moment, and this measuring mechanism is simple in structure and cost is lower; Limit the relative rotation angle of outer shroud and interior ring by tie-down cable or limited block, thereby protected torsion spring, improve the reliability in joint.
Accompanying drawing explanation
Fig. 1 is the cutaway view of the flexible joint of the present invention's mixing control;
Fig. 2 is the structural representation of the flexible joint of the present invention's mixing control;
Fig. 3 is the structural representation with the plane torsion spring of tie-down cable;
Fig. 4 is the structural representation with the plane torsion spring of limited block.
1. sensor stator, 2. rotor sensor, 3. drive plate, 4. clutch shaft bearing, 5. torsion spring, 6. location bearing, 7. output shaft, 8. cross roller bearing, 9. output flange, 10. flexbile gear, 11. have just taken turns, 12. wave producers, 13. motor stators, 14. rotors, 15. Hall elements, 16. second bearings, 17. first stators, 18. machine shafts, 19. the first rotors, 20. first pedestals, 21. end caps, 22. elastomers, 23. tie-down cables, 24. interior rings, 25. outer shrouds, 26. cushion collars, 27. limited blocks, 28. absolute type angular transducers, 29. motor encoders, 30. electric machine casings.
The specific embodiment
As shown in Figure 1, 2, a kind of flexible joint that mixes control, comprising:
With the motor of harmonic wave drive speed reducer;
The torsion spring 5 being connected with the output shaft 7 of harmonic wave drive speed reducer;
The rotating mechanism that driven by torsion spring 5;
By the motor encoder 29 for measuring machine shaft 18 corners, and the measuring mechanism forming for measuring the absolute type angular transducer 28 of rotating mechanism corner.
The motor stator 13 that motor comprises machine shaft 18, electric machine casing 30, is arranged on the rotor 14 on machine shaft and cooperatively interacts with rotor, and Hall element 15 is installed on motor stator 13.Machine shaft 18 is by the alignment of the second bearing 16 in end cap 21 and 4 assurances of the clutch shaft bearing in drive plate 3 and motor housing 30.
Harmonic wave drive speed reducer comprise wave producer 12, with fixing firm wheel 11, the flexbile gear 10 of electric machine casing 30, flexbile gear 10 is connected with output shaft 7 by output flange 9.When machine shaft 18 rotates, by wave producer 12 and flexbile gear 10, rotation is delivered on output shaft 7 through output flange 9, output flange 9 and output shaft 7 are rotatably assorted by cross roller bearing 8 and electric machine casing 30.
Torsion spring 5 comprises:
The outer shroud 25 being rotatably assorted with the inwall of electric machine casing 30;
With the fixing interior ring 24 of the output shaft 7 of harmonic wave drive speed reducer;
Be fixed on three elastomers 22 between outer shroud and interior ring, and elastomer is along inner circumference along being uniformly distributed, the band shape that elastomer is reciprocal bending.Torsion spring can improve submissive and mechanism stored energy for joint, and the back and forth banded elastomer processing of bending, easy for installation, and when torsion spring inner and outer rings is rotated mutually, good reliability, precision are high.As shown in Figure 3, between outer shroud 25 and interior ring 24, be provided with the tie-down cable 23 for limiting ultimate angle.Tie-down cable has certain length, and in the time that outer shroud and interior ring turn to certain position, thereby tie-down cable is straightened, restriction outer shroud and interior ring further relatively rotate, and prevents when moment of torsion is excessive torsion spring to produce and destroy, thereby plays the effect of position limitation protection.Except tie-down cable can also extend to the limited block 27 between outer shroud and interior ring in inner walls setting, and on limited block, be arranged with cushion collar 26, see Fig. 4.In the time that outer shroud and interior ring turn to certain position, elastomer contacts with limited block, thereby restriction outer shroud and interior ring further relatively rotate, and cushion collar plays cushioning effect, protection elastomer and limited block.
Rotating mechanism comprises drive plate 3, and drive plate 3 is fixing with outer shroud 25, and drive plate and outer shroud are rotatably assorted by location bearing and electric machine casing 30.Absolute type angular transducer 28 comprises the rotor sensor 2 and the sensor stator 1 that cooperatively interact, and sensor stator 1 is fixed on electric machine casing 30, and rotor sensor 2 is fixed on the drive plate 3 of rotating mechanism.In the time that rotating mechanism rotates, there is relative motion in rotor sensor 2 and the sensor stator 1 of absolute type angular transducer, thereby record the angle of rotating mechanism rotation.
Machine shaft 18 is the extension that passes electric machine casing away from one end of rotating mechanism, and motor encoder 29 comprises:
The first pedestal 20, interfixes with electric machine casing 30, and is in the periphery of extension;
The first stator 17, is fixed on the first pedestal;
The first rotor 19, is fixed on machine shaft, matches with the first stator.
In the time that machine shaft 18 rotates, there is relative motion in the first stator 17 and the first rotor 19 of motor encoder, thereby records the anglec of rotation of machine shaft.
When real work, can detect the angle of rotating mechanism actual rotation by being arranged on the absolute type angular transducer 28 of rotating mechanism end, by the feedback using its signal as whole joint output angle, can realize high-precision position closed loop control, than realizing Position Control by insertion force or Torque Control, this control method is simpler, and precision is higher, responds faster.Can record by motor encoder 29 and absolute type angular transducer 28 angle that torsion spring reverses, this angle is multiplied by the coefficient of elasticity of torsion spring, can obtain the actual moment applying of rotating mechanism.Flexible joint in the present invention has been realized the mixing control of power and position, not only makes structural design and maintenance become and is more prone to, but also reduced cost, has improved the stability of a system.