The unfriendly-for-humans environment of space causes automatic or remotely controlled vehicles and devices to be used for its research. In robot and manipulator control systems, and also in mechanisms adjusting antennas and photovoltaic panels, the hermetic harmonic drive can be used. A special advantage of this type of gear is the ability to transfer power to an isolated space separated by physical barriers from external influences. Therefore, the purpose was to design gears that will allow achieving the highest kinematic precision for control systems by simultaneously maintaining their hermetics. The article presented an analysis of the kinematic accuracy of harmonic hermetic drives powered by four different types of wave generators. The generators used differed in construction but also caused other deformations of the flexspline. The calculation of angular displacement was prepared in the computer program Abaqus. The simulations were performed on virtual models of a complete harmonic hermetic drive using the finite element method (FEM). The results from the analysis allow the most favorable solution to be applied to the Mars rover drive or spacecraft control system. It was determined for which of the wave generators the kinematic accuracy is the highest and how high the backlash exists for the reversing rotation. Finally, the proposed design will allow one to increase the accuracy of the working movements and control of space vehicles while ensuring a minimal influence of the external ambient.
1 December 2016 in Advances in Science and Technology Research Journal
The article presents the numerical analysis of the impact of geometry errors on the motion transmission of dual path gearing. The strength calculations of the elements of the drive were made by means of the Finite Elements Method (FEM). The calculations were made for the two-dimensional models of...
1 January 2020 in Journal of Theoretical and Applied Mechanics
This paper presents a comparative analysis with different models of the flexspline for a harmonic hermetic drive. The flexspline is a thin-walled construction, deforming during work, so its design is a very complicated process. The paper contains a strength analysis for some selected models of this gear. Calculations were performed using the finite element method (FEM) in ADINA. The work presents stress diagrams in longitudinal intersections for susceptible wheels of different shapes for direct comparison. Suggested changes in construction of the flexspline will increase durability of a welded hermetic gear.
This article includes an analysis of the possibility of using polymer materials for the production of harmonic drive. The use of additive methods greatly eases and accelerates the manufacturing of the flexspline. In the case of gears made of polymeric materials using rapid prototyping (RP) methods, the problem is often with their mechanical strength. In a harmonic drive, the wheel is uniquely exposed to damage, because during work, it deforms and is additionally loaded with torque. Therefore, numerical calculations were conducted using the finite element method (FEM) in the Abaqus program. As a result, information was obtained on the distribution of stresses in the flexspline and their maximum values. On this basis, it was possible to determine whether a flexspline made of specific polymers could be used in commercial harmonic drives or whether they were only adequate for the production of prototypes.
In the study, measurements of 3D deformations of the flexspline in harmonic drive were performed by applying a digital image correlation (DIC) method. The tests were carried out with the use of physical 3D printed models made of ABS copolymer (acrylonitrile-butadiene-styrene), which ensured sufficient capacity andrigidity of the structures. The findings related to deformations in flexspline, obtained through bench testing, were compared to the results of calculations conducted using the finite element method (FEM). Significant convergence in the findings obtained using the two methods was shown, yet deformations measured in the real-life model were characterized by greater irregularity compared to the corresponding solutions obtained with the numerical method. The results obtained through optical measurement confirm that physical models made of plastics, built using rapid prototyping technology, can justifiably be appliedin bench testing of prototype gear transmissions.