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CN-122016109-A - Built-in torque measurement method of harmonic reducer based on independent gain adjustment and torque sensor system

CN122016109ACN 122016109 ACN122016109 ACN 122016109ACN-122016109-A

Abstract

The invention belongs to the technical field of robot sensing, and discloses a method for measuring built-in torque of a harmonic reducer based on independent gain adjustment, wherein M strain gauges are arranged on the surface of a diaphragm part of a flexible gear of the harmonic reducer; the number M of the strain gauges meets M more than or equal to 2N+1, wherein N is the highest order of the ripple interference signal frequency components to be compensated. In order to eliminate the ripple of N frequency components, the invention needs a minimum of 2N+1 strain gauges. Therefore, by arranging 3 or more strain gages (e.g., M≥3) on the flexspline diaphragm portion, an information redundant sensing array is formed, so that the system has enough degrees of freedom to simultaneously characterize the ripple interference of the true torque signal with multiple frequency components.

Inventors

  • CHEN JUNJIE
  • WU RUOJUN
  • LI JIAXIN
  • CHU GUOFU
  • LIANG ZIJIAN

Assignees

  • 深圳安培龙科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The method for measuring the built-in torque of the harmonic reducer based on independent gain adjustment is characterized by comprising the following steps of; Step 1, arranging M strain gauges on the surface of a diaphragm part of a flexible gear of a harmonic reducer; Step 2, configuring independent signal amplification channels for each strain gauge, wherein each signal amplification channel has a corresponding adjustable gain coefficient ; Step 3, synchronously collecting original output signals of each strain gauge in the operation process of the harmonic reducer; step 4, adjusting gain coefficients corresponding to the signal amplification channels based on the original output signals The periodic ripple components related to the rotation of the harmonic speed reducer in the output signal of each strain gauge after gain adjustment are mutually counteracted after weighted summation, so that the output of the total ripple signal is minimized; And step 5, taking the sum of the output signals of all the signal amplifying channels after gain adjustment as a final torque measurement value.
  2. 2. The method for measuring built-in torque of a harmonic reducer according to claim 1, wherein, The number M of the strain gauges meets M more than or equal to 2N+1, wherein N is the highest order of the ripple interference signal frequency components to be compensated.
  3. 3. The method for measuring built-in torque of a harmonic reducer according to claim 2, wherein, The number M of the strain gauges is an odd number.
  4. 4. A method for measuring built-in torque of a harmonic speed reducer according to claim 2 or 3, The number M of strain gauges is at least 3 for compensating the fundamental frequency component of the ripple signal.
  5. 5. The method for measuring built-in torque of a harmonic reducer according to claim 4, wherein, When (when) When the flexible gear diaphragm part is used, three strain gauges are arranged on the surface of the flexible gear diaphragm part along the circumferential direction, the position interval of the strain gauges corresponds to one third of the fundamental frequency period of a ripple signal, or the strain gauges are arranged on the opposite sides of the flexible gear by using symmetry.
  6. 6. The method for measuring built-in torque of a harmonic reducer according to claim 2, wherein, The gain factor is determined in the step 4 Adopts a deterministic method, and the step 4 comprises the following steps: establishing a signal amplitude comprising ripple And phase of Is a homogeneous linear system of equations: ; Wherein, the M is the design coefficient of the gear, Is the rotation angle of the input shaft; And obtaining the amplitude and the phase of each strain gauge signal through Fourier transformation, presetting one gain value, solving the equation set to obtain the relative values of the rest gains, and finally adjusting all the gains through a scale factor to match the required torque sensitivity.
  7. 7. The method for measuring built-in torque of a harmonic reducer according to claim 1, wherein, The gain factor is determined in the step 4 Adopts a heuristic method, and the step 4 comprises the following steps: The output signals of all the strain gauges after gain adjustment are weighted and summed to obtain a composite signal; monitoring the peak value of the synthesized signal in the operation process of the harmonic reducer; By fine tuning the gain of each channel until the ripple amplitude in the composite signal is minimized.
  8. 8. The method for measuring built-in torque of a harmonic reducer according to claim 1, wherein, The strain gauge is adhered to the inner side or the outer side of the flexible gear diaphragm part.
  9. 9. The method for measuring built-in torque of a harmonic speed reducer according to claim 8, wherein, The strain gauge is adhered to the inner side of the flexible gear diaphragm part near the hub, and the lead wire is fixed on the stationary hub, so that the durability of the sensor under long-term operation is improved.
  10. 10. A harmonic reducer torque sensor system applying the harmonic reducer built-in torque measurement method according to any one of claims 1 to 7, characterized by comprising: A harmonic reducer body; A plurality of strain gauges attached to the flexible gear diaphragm portion; the multichannel analog amplifying circuit corresponds to each strain gauge, and each channel has independent adjustable gain; a summing circuit for weighted summing all signal amplification channel output signals; the output end of the summing circuit provides a ripple compensated torque measurement signal.

Description

Built-in torque measurement method of harmonic reducer based on independent gain adjustment and torque sensor system Technical Field The invention belongs to the technical field of robot sensing, and particularly relates to a method for measuring built-in torque of a harmonic reducer based on independent gain adjustment and a torque sensor system. Background Among a plurality of transmission mechanisms, the harmonic reducer is widely applied to high-dynamic performance scenes such as industrial robots, cooperative robots, spaceflight mechanical arms, medical operation robots and the like due to the advantages of compact structure, large transmission ratio, small back clearance, high precision and the like. In order to meet the requirement of closed-loop force control, the traditional scheme is to arrange a torque sensor outside the output end of the harmonic reducer, however, the main current internal torque measurement method is to paste a resistance strain gauge on the surface of a flexible gear of the harmonic reducer, convert a strain signal into voltage output through a Wheatstone bridge circuit, and further invert the output torque. The method has the advantages of simple structure, quick response and the like, but is limited by a unique working mechanism of the harmonic reducer, namely, the flexible gear is forced to generate periodical elliptical deformation under the action of the wave generator, so that the strain gauge responds to the stress caused by real torque, and a periodical interference signal which is caused by elliptical deformation and is strongly related to the position and the rotating speed of the rotor is superimposed, and is commonly called as 'ripple' in the industry. To suppress this ripple, the prior art has mostly employed a symmetrical arrangement of two or four strain gages to form a full-bridge or half-bridge circuit, in an attempt to cancel common-mode interference on the circuit by physical symmetry. However, due to the unavoidable factors of micron-level position deviation, material anisotropy, non-ideal elliptical deformation of the flexspline, etc. in the manufacturing and assembling processes, the actual strain field distribution is difficult to be completely symmetrical, and in particular, the higher-order harmonic components cannot be effectively counteracted (the residual error is about 4% of the maximum torque). Another class of solutions attempts to introduce digital signal processing techniques, such as post-processing the original signal with a kalman filter, a low pass filter, or an adaptive filtering algorithm to suppress the ripple. However, such methods typically introduce a computational delay of about 1 millisecond, significantly reducing the system control bandwidth, affecting dynamic response performance, and particularly presenting a potential safety hazard in high-speed trajectory tracking or sudden collision detection scenarios. Disclosure of Invention In view of the above, the present invention is directed to a method for measuring built-in torque of a harmonic reducer and a torque sensor system based on independent gain adjustment, so as to solve the above-mentioned problems in the prior art. In order to solve the technical problems, the first technical scheme of the invention is a built-in torque measuring method of a harmonic reducer based on independent gain adjustment, which comprises the following steps of; Step 1, arranging M strain gauges on the surface of a diaphragm part of a flexible gear of a harmonic reducer; Step 2, configuring independent signal amplification channels for each strain gauge, wherein each signal amplification channel has a corresponding adjustable gain coefficient ; Step 3, synchronously collecting original output signals of each strain gauge in the operation process of the harmonic reducer; step 4, adjusting gain coefficients corresponding to the signal amplification channels based on the original output signals The periodic ripple components related to the rotation of the harmonic speed reducer in the output signal of each strain gauge after gain adjustment are mutually counteracted after weighted summation, so that the output of the total ripple signal is minimized; And step 5, taking the sum of the output signals of all the signal amplifying channels after gain adjustment as a final torque measurement value. Preferably, the number M of the strain gauges satisfies M more than or equal to 2N+1, wherein N is the highest order of the ripple interference signal frequency component to be compensated. Further, the number M of the strain gauges is an odd number. Further, the number M of strain gages is at least 3 for compensating the fundamental frequency component of the ripple signal. Further, when m=3, three strain gages are arranged in the circumferential direction on the surface of the diaphragm portion of the flexspline, the position intervals of the strain gages corresponding to one third of the fundamental frequency