• Journal of the Korean Society for Precision Engineering
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• v.19 no.4
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• pp.124-131
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• 2002

In this paper, an extended volumetric error model considering backlash in a three-axis machine tool was proposed and utilized for calculating the volumetric error of the machine tool at any position in three-dimensional workspace. Backlashes are interrelated; i.e. the angular backlash affects the straightness errors which then affect talc calculated squareness errors. Therefore, a new concept was introduced to define the backlash of squareness errors to incorporate the backlash of squareness error into the volumetric error, and the characteristics of the backlash of squareness error were investigated. The effects of backlash errors were assessed, by experiments. for 21 geometric errors of a machine tool. The backlash error was shown to be one of the systematic errors of a machine tool. And a generalized volumetric error model formulator for three-axis machine tools was developed, which allowed us to formulate machine tool synthesis error models far all possible machine tool configurations only with machine tool topology information. Based on these volumetric error model and model formulator, a computer-aided volumetric error analysis system was developed for a three-axis machine tool in this paper. Then the volumetric error at an arbitrary position can be obtained, and displayed in a three-dimensional graphic form.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.676-680
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• 2000

In this paper, an extended volumetric error model considering backlash in a three-axis machine tool was proposed and utilized for calculating the volumetric error of the machine tool at any position in three-dimensional workspace. Backlashes are interrelated; i.e. the angular backlash affects the straightness errors which then affect the calculated squareness errors. Therefore, a new concept was introduced to define the backlash of squareness errors to incorporate the backlash of squareness error into the volumetric error, and the characteristics of the backlash of squareness error were investigated. The effects of backlash errors were assessed, by experiments, fur 21 geometric errors of a machine tool. The backlash error was shown to be one of the systematic errors of a machine tool. Based on this volumetric error model, a computer-aided volumetric error analysis system was developed for a three-axis machine tool in this paper. Then the volumetric error at an arbitrary position can be obtained, and displayed in a three-dimensional graphic form.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.1
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• pp.69-78
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• 1997

Main sources of the vibration in gear driving system are transmission error and backlash. Transmission error is the difference of the rotation between driving and driven gear due to tooth deformation and profile error. Vibro-impacts induced by backlash between meshing gears lead to excessive vibration and noise in many geared rotation systems. Nonlinear dynamic characteristics of the gear driving system due to transmi- ssion error and backlash are investigated. Transmission error is calculated for spur gear. Nonlinear equation of motion for the gear driving system is developed with the calculated transmission error and backlash. Numerical analysis of the equation and the experimental results show the existence of meshing frequency, superharmonic compon- ents. Instability of the gear driving motion is found on the basis of Mathieu equation. Rattle vibration due to backlash is also discussed on the basis if nonlinear jump phenomenon.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.7
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• pp.34-42
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• 2022

Minimizing the backlash of gears and reducers is important for their proper and precise functioning. In this study, an automatic backlash measuring system was developed for the mass production and quality control of a military-grade reducer. The developed automatic backlash measurement system eliminates human error during the backlash measurement process. It also reduces the manufacturing time and digitizes the backlash number. The system was tested for an aircraft machine gun control reducer that required low-torque and high-precision conditions. The test results show that the torque range was 0.820-4.788 Nm. The maximum torque error is less than 0.231 N·m at 2.943 N·m, and 1.2 arcmin of the maximum backlash error with ± 0.3 arcmin of repeatability. The developed system satisfies all required conditions: torque of 1-3 Nm, torque accuracy within ± 0.5 N·m, and backlash accuracy of ± 3 arcmin.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.192-194
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• 2006

Backlash between meshing gear teeth causes impact, tracking error and undesired vibrations. It is usually minimized by precision gear, spring-loaded anti-backlash gears and precise mechanical adjustment. Although these techniques can help to reduce the backlash gap, its cost is relatively high and performance is limited. And the classic controller is insufficient to control the dynamic system with nonlinearity. For these reason, a fuzzy controller is proposed to compensate the backlash effect at a robot system. The input variables are position error and change in error. The output variable can be defined by input voltage of motor. The performance of a fuzzy controller is verified by comparing with a PID controller. The results show that the undesired vibration is suppressed. And then diminishing the position error is observed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.73-78
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• 2001

Main sources of the vibration of a gear-pair system are backlash and transmission error. This paper investigates the dynamics of a gear-pair system involving backlash and transmission error. This paper presented 4 types of gear motions due to the existence of a backlash. The solutions are calculated using a multiple-time scale method and numerically. The results shows the existence of 4 type motions, jump phenomenon, and chaotic motion consequently the design of gear driving system with low vibration and noise requires the study on the effects of transmission error and backlash, i.e. nonlinearities in gear driving system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.921-928
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• 2002

Main sources of the nitration of a gear-pair system are backlash and transmission error, the difference between required and actual rotation during gear meshing. This paper presents the nonlinear dynamic characteristics of gear motions due to the existence of backlash and periodic variation of meshing stiffness, which is assumed as a one-term harmonic component. Gear motions are classified as three types with the consideration of backlash. Each response is calculated using the harmonic balance method and confirmed by numerical integration. The responses with the increase of the rotating speed show abrupt changes in its magnitude for the variation of the preload, exciting force, and damping coefficient. The result also shows that there is a chaotic motion with some specific design parameters and operating conditions In gear diving system. Consequently the design of gear driving system with low nitration and noise requires the study on the effects of nonlinear dynamic characteristics due to stiffness variation and backlash.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2461-2463
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• 2000

This paper presents a scheme for designing a fuzzy observer for servo control system with nonlinear element, i.e., backlash. It is found that backlash occurs when the feed direction is reversed. Due to the imperfect transient response of the driving mechanism, not only the static backlash error but also the dynamic backlash error is generated on the contouring profile. And also, we utilized two inertia modeling in order to deals with coupled system accurately. The overall control system consists of two parts - a servo controller and an Fuzzy obsever. It is a Takagi-sugeno type fuzzy model whose consequent part is of the state space form is obtained. A simulation is carried out to demonstrate the effectiveness of the proposed scheme.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.187-189
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• 2006

In mechanical system, gear trains have backlash innately. With the presence of inherent backlash, the overall system performance is limited in many practical control systems. It has been reported that a disturbance observer has the property of effective removing disturbance and cutting measurement noise off. The plant is remodeled with modified disturbance observer to observe and compensate backlash characteristics. And this paper describes a method to design Q filter and to analyze the effects of disturbance and measurement noise to the output. It is shown that the vibration and tracking error caused by backlash were decreased and the time constant and relative degree are important factor to design Q filter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.632-635
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• 2002

In this paper, a general procedure to determine machine tool errors from the on-machine measurement (OMM) data is described. First, a parameterized error model of a machine tool is illustrated by approximating error components as linear function of axis positions, and a modified error model is proposed which includes backlash effects. To determine the unknown model coefficient vectors of the forward and backward error model, an artifact with 8 cutes is made and calibrated on CMM. Then, lower-left and upper-right cube corners are measured with a touch-trigger probe mounted on the machine tool spindle. Measured error data are used to determine the coefficient vectors. The positioning errors in the XY plane at the fixed z position are simulated for the forward and backward error model.