harmonic drive disadvantages harmonic drive disadvantages

These include: increased electrical usage, increased wear and tear on motors or equipment, higher maintenance cost, power quality problems upstream and downstream of the load, and utility penalties for creating problems for the power grid. Option to simulate ring gear rotation. Composite Structures, 1999, 47(1): 827833, Article Gearhead Selector Number of teeth protruding inward from the circular ring gear M. Masoumi. Based on your location, we recommend that you select: . Harmonic Drive Linear Actuators deliver both high force and outstanding positional accuracy. On this Wikipedia the language links are at the top of the page across from the article title. Copyright Zhejiang Qiyue Mechanical Technology Co., ltd. Rights Reserved. transfer between the input and output shafts. China Harmonic Drive Disadvantages, Find details about China Gear Reducer, Gear Motor from Harmonic Drive Disadvantages - Shenzhen Homwing Technology Co., Ltd. temperature-load-efficiency lookup table for High reduction ratios allow precise adjustments with minimal torque. By($4IFhNg9nk8Nr%s=g^^{7T&5IMjR\'KU)8Qy9RgDIzK59w(,y{wykztyB_!j89G>=t;o;VX,{3 Option to include friction meshing losses: No meshing losses - Suitable for HIL Choi, Wonje degree. A: Applications that require multiple VFDs typically produce a higher level of harmonic distortion due to the intrinsic nature of VFD technology. The ratio of the two gear tooth numbers defines the Size:14,17,20,25,32 Price excludes VAT (USA) Understanding and modelling the torsional stiffness of harmonic drives through finite-element method. For this case, <> [7] Therefore, it is not an appropriate measure of central tendency for skewed distribution. Also, there are other non-backlash gear options like split gears with springs to eat up backlash. Below this value, a 2022 Harmonic Drive LLC | 978-532-1800 tangent function smooths the efficiency factor to one, lowering the One of the many advantages of a harmonic drive is the lack of backlash due to the unique design. endobj This results in significant flexibility of the walls at the open end due to the thin wall, and in the closed side being rigid enough to be tightly secured (to a shaft, for example). Chae, Joonbo Li, Hongguang <> temperature change. 3. Mechanical transmission system with flexing, "Decentralized robust control of robot manipulators with harmonic drive transmission and application to modular and reconfigurable serial arms", Harmonic Drive Systems Company Information, "Qualifying Bulk Metallic Glass Gear Materials for Spacecraft Applications", Explanation of the principles behind strain wave gearing (Youtube), Harmonic drive function demonstration (Youtube), https://en.wikipedia.org/w/index.php?title=Strain_wave_gearing&oldid=1120622080, Articles with dead external links from April 2021, Articles with unsourced statements from September 2022, Articles with unsourced statements from November 2020, Creative Commons Attribution-ShareAlike License 3.0, Middle circle: flex spline (attached to output shaft, not shown), Inner oval: wave generator (attached to input shaft; inner ball bearing and shaft, not shown). To enable this parameter, set Inertia to and follower shafts. These devices seem really cool, but I thought I would catalog the disadvantages here since they are rarely discussed and I didn't see any previous posts addressing them. When you set Ring gear rotation to This is the sun gear. I don't think the lack of backlash is due to the bearing. foundation for this block. [4] It can provide gear reduction but may also be used to increase rotational speed[citation needed], or for differential gearing. On. [4] It can provide gear reduction but may also be used to increase rotational speed[citation needed], or for differential gearing. Lee, Sangkuk Sim, Jaehoon <> Thermal conserving port associated with heat transfer. The device consists of a thin ring that deflects elastically as it rolls inside a slightly larger rigid circular ring. The harmonic drive is the only gear arrangement that doesnt feature any backlash or recoil effect, or at least they are negligible in practice. Robotica, 1992, 10(4): 369375, Article The bearings allow the strain wave generator to rotate within the elliptical gear. This is connected to an element called wave generation which has an elliptical shape and is encircled by an elliptical ball bearing. reconfigurable ratios within a standard housing. The electrically driven wheels of the Apollo Lunar Rover included strain wave gears. doubles the teeth in mesh, thereby increasing the torque capacity of the drive system. Thus the flex spline spins at 1/100 the speed of the wave generator plug and in the opposite direction. elliptical gear, and the second element represents the relationship The third harmonic then has four nodes and three anti-nodes. Item No. The wave generator is also connected to the motor shaft. Angeles, J. This is the carrier gear. from the strain wave generator to the elliptical gear. The default array corresponds to zero viscous A hyperbolic tangent function smooths The range of possible gear ratios is limited by tooth size limits for a given configuration. gear array. US Patent, 1960, Tuttle T D. Understanding and modeling the behavior of a harmonic drive gear transmission. Mechanical rotational conserving port associated with the base shaft The mechanism has three basic components: a wave generator (2 / green), a flex spline (3 / red), and a circular spline (4 / blue). <> follower shafts. This can either be achieved by changing the mechanism's diameter or by changing the size of the individual teeth and thereby preserving its size and weight. the efficiency factor from zero when at rest to the full efficiency Zero backlash Harmonic Drive and low backlash Harmonic Gearhead Planetary Quick Connect gearboxes easily mount to any servomotor to create a high precision actuator. This means that for every full rotation of the wave generator, the flex spline would be required to rotate a slight amount (two teeth in this example) backward relative to the circular spline. All in all, you should not ignore gear drive disadvantages. A: Depending on the electrical power system, there are a lot of places where harmonics can cause inefficiencies. She holds a bachelors degree in mechanical engineering from the University of Tennessee and an MBA from the University of Florida. Mech. Part C, Journal of Mechanical Engineering Science, 2009, 223(2): 515524, Dong H, Zhu Z, Zhou W, Chen Z. The most notable examples of harmonic drive applications include the wheels of the Apollo Lunar Rover and the winches of the Skylab space station. >OKF"{zR },iDTLz array and at the loads in the Load at elliptical Lee, Dai Gil This is in addition to the costs of the reduced life span of the motors caused by the heating effects of the harmonic currents. r /WoUB bE+_{t9FLDe0gG^_8+~J&va[`Jw\ x/wn 1995. and the strain wave generator. Shariatee, Morteza The strain wave gearing uses the elasticity of metal. We offer a complete range of digital servo drives for brush or brushless actuators. The best. Nowadays, there are only a handful of manufacturers in the USA, Germany, and Japan who are holding the license to produce harmonic drives, doing so at their top-notch facilities and producing ultimate quality strain gears for the whole world. ), More susceptible to fatigue damage source, Large moment of inertia and starting torques, not suitable for low power drives (see above), Not able to yield gear ratios less than 1:35 (see above), Instantaneous transmission ratio is not constant. A: Inductive motors mitigate higher-order harmonics by providing high-input impedance that limits high-frequency currents. 2017. This means that the circular spline does not assume the elliptical shape of the other two components, but instead, it simply meshes its inner teeth with those of the outer flex spline side, resulting in the rotation of the flex spline. transfer by a variable efficiency factor that depends on A: Benefits can include controlled capital expenses, IEEE-519 compliance, increased uptime and profits, added value to facilities and reduced energy expenses. rotation to Off. Seyfferth, W. endobj The internal meshing between the two gears causes the elliptical gear axis to spin teeth of the elliptical gear to slowly climb the teeth of the circular ring gear. Mechanical Design Engineering Career, Famous Engineers: The 10 Who Changed The World, Engineering Problems: 5 Hot Challenges for Future Engineers, Solar Powered System Extracts Drinking Water From Dry Air, Planetary Gears a masterclass for mechanical engineers. Ing. To enable this port, set Friction model to There are three elements in a basic Harmonic Drive: a circular spline, a flexspline, and a wave generator. Temperature-dependent efficiency, the Discover how zero backlash Harmonic Drive strain wave gearing works, US Locations Available in a wide range of gear ratios, sizes and output configurations. output torque. Also, obtained vibration equations are utilized to study the effects of different involved parameters such as the geometry of the flexspline and its gear tooth, eccentricity, and unbalancing on the vibrational behavior of the system. 6 0 obj and Machine Tool & Hydraulics, 1995, 6: 336339, Musser C W. Strain wave gear-species. Absolute value of the follower shaft angular velocity above which the The elliptical plug is inserted into the bearing, forcing the bearing to conform to the elliptical shape but still allowing rotation of the plug within the outer bearing. Gear block. endstream This is advantageous for systems that require precise gear positioning. MathSciNet Choi, Wonje Russian Engineering Journal, 1974, 54: 4752, Shuvalov S. Calculation of forces acting on members of a harmonic gear drive. and high-ratio speed reduction mechanism that contains three key components: A harmonic drive is backlash-free with a high-ratio of speed reduction by design. International Journal of Robotics Research, 1997, 16(2): 214239, Rong H. Research About Vibration of Harmonic Drives. the effects of heat flow and temperature change by enabling the optional thermal port. This gives a very good level of torque transmission. Park, Sumin throughout the simulation. Option to include inertia due to ring gear motion in your } Taghirad, H. D. This guideline establishes the level at which electrical energy is determined clean.. Harmonic Drive is a registered trademark of Harmonic Drive. Cookie Notice Answer (1 of 2): I'm assuming you're referring to home audio systems. The material takes up this wavy motion by flexing according to the rotation of the input shaft and also creates an elliptical shape. Efficiency array. thresholds. Kim, Minsung On, the block calculates the efficiencies by High gear reduction ratios of up to 30 times that achieved with planetary gears are possible in the same space. Technical Report, Massachusetts Institute of Technology Cambridge Artificial Intelligence Laboratory, 1990, Legnani G, Faglia R. Harmonic drive transmissions: the effects of their elasticity, clearance and irregularity on the dynamic behaviour of an actual SCARA robot. endobj and volume8,pages 409419 (2013)Cite this article. hasContentIssue true, Copyright Cambridge University Press 1992. ring gear by using a mechanical rotational input signal. Underwater Welding 101: Read this and be an expert in 5 minutes! 09 March 2009. Belanger, P. R. In: proceedings of ASME Design Technical Conferences: 19th Advances in Design Automation. This paper deals with the study of the effects of Harmonic Drives characteristics on the dynamic behaviour of industrial robots. block smooths the efficiency factors between zero when at rest and the 25 Best Paying Jobs in Energy, Top Aerospace Companies to Work For. This article was most recently revised and updated by, https://www.britannica.com/technology/Harmonic-Drive, Academia - Application of Harmonic Drive Gears in Machine Tools. Learn more about Institutional subscriptions, Rong H. Research on amplitude value of vibration in harmonic gear. Option to include inertia due to ring gear rotation in your Harmonic Drive Features Backlash-free, precise and reliable - the list of striking advantages and unique selling points of Harmonic Drive products is long. shaft equals zero. gear reduction ratio is. to Temperature and load-dependent It was first used successfully in 1960 by USM Co. and later by Hasegawa Gear Works under license of USM. completely dissipates due to meshing losses. 1 and varies with the torque load. <>>> S of the Planetary In this lesson, Ian. Item No. A: Systems with heavy motor, VFD and lighting loads need to be aware of the problems that harmonics can cause. Google Scholar, Thompson B R. The PHD: A Planar, Harmonic Drive Robot for Joint Torque Control. So for example, if the flex spline has 100 teeth and the circular spline has 105, the reduction ratio is (100 105) / 100 = -0.05 which means that the flex spline ration is -5/100 (minus indicates the opposite direction of spin). Geared to solve problems. Array of efficiencies used to construct a 1-D temperature-efficiency USA, Cincinnati, 1990, 368373, Chapter We use cookies to distinguish you from other users and to provide you with a better experience on our websites. This reduction ratio is applicable to the configuration where the circular spline is fixed, the wave generator the input and the flexible spline the output. Gear meshing is ideal. I think it's simply a function of the large gear ratio, so the backlash is negligible. Has data issue: true Simple Gear block implementation. Contact Us, Rotary Actuators Kwak, Nojun Disadvantages include a tendency for 'wind-up' (a torsional spring rate) in the low torque region. Each element in the vector must be in the range (0,1]. Q: What are the different types of low harmonic solutions? This includes minimizing costs, capital expenses and unplanned downtime. The wave generator is elliptical in shape and acts as a link with two rollers that rotates within the flexspline, causing it to mesh with the circular spline progressively at diametrically opposite points. Harmonic Drive rotary actuators are the easiest solution for your high precision motion control applications. Sim, Jaehoon GPM Announces New Hires and Staff Promotions. Please read our cookie notice for more information on the use of cookie on this website. Mechanical Transmission, 1995, 1: 3336, Taghirad H D, Belanger P. Torque ripple and misalignment torque compensation for the built-in torque sensor of harmonic drive systems. circular ring gear. Employment Component Sets Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Kim, Jeeseop Champliaud, H It operates on a principle different from that of conventional speed changers. Harmonic drive systems are precise and specific transmission gear systems which are beneficial in terms of the high transmission ratio and almost zero backlash. Cho, Hyunbum IEEE Transactions on Robotics and Automation, 1993, 9(1): 108116, Jeon H S, Oh S H. A study on stress and vibration analysis of a steel and hybrid flexspline for harmonic drive. {\displaystyle R} Akbarzadeh, Alireza Temperature-dependent Choose a web site to get translated content where available and see local events and offers. to normalize the load-dependent efficiency. High gear reduction ratios of up to 30 times that achieved with planetary gears are possible in the same space. The base shaft turns the strain wave generator, which is elliptical with bearings around the circumference. ]BJ, One of the many advantages of a harmonic drive is the lack of backlash due to the unique design. R When a linear electrical load is connected to the system, it draws a sinusoidal current at the same frequency as the voltage, though usually not in phase with the voltage. Looking for an older product or a replacement part? The efficiency of a typical harmonic drive measured on real shaft to shaft tests by the manufacturer goes up to 90%. power quality. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. 3.It has a fully sealed structure and is easy to . https://doi.org/10.1007/s11465-013-0275-5. Second, they can not avoid the harmonic vibration. Akbarzadeh, Alireza vector. Russian Engineering Journal, 1978, 58(7): 1922, Emelyanov A. The wave generator is made of two separate parts: an elliptical disk called a wave generator plug and an outer ball bearing. Use the Variables settings to set the priority and initial target As a guideline, the angular velocity threshold should be lower than HARMONIC DRIVES Harmonic Drive Animation Harmonic Drive Harmonic Drives also known as strain wave gearing because harmonic drive gears are strain wave gears produced by the harmonic drive companies is a special type of mechanical gear system that can improve certain characteristics compared . The harmonic drive is a type of gear arrangement often referred to as a strain wave gear because of the way it works. torque between the gear wheel pairs is defined by the table lookup based on 2009. endobj <>/ExtGState<>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/Annots[ 15 0 R 17 0 R] /MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Strain wave gearing has some advantages over traditional gearing systems such as helical or planetary gears, including: High gear reduction ratios are possible in a small volume (a ratio from 30:1 up to 320:1 is possible in the same space in which planetary gears typically only produce a 10:1 ratio). Total loading time: 0 I don't recall if this was an issue when I have used them (it's been a long time), but since they only mesh at two teeth, I'd think it would be relatively low. Thus the rotation action of the wave generator results in a much slower rotation of the flex spline in the opposite direction. Harmonic drives have wide applications in various domains, from large and hard working machine tools, to the medical and electronic equipment with small components and silence functioning, due to. 1995. represents the relationship between the strain wave generator and the 12 0 obj Active front-end drives have insulated gate bipolar transistors (IGBT)front-end technology that pulls relatively linear power from the line and uses an L-C-L (inductor-capacitor-inductor) filter to mitigate the IGBT switching noise. Masoumi, M., Alimohammadi, H. An investigation into the vibration of harmonic drive systems. Harmonic voltages and currents in a Power System are a result of non-linear electric loads. 1998. Achieving reduction ratios of 1/100 and up to even 1/300 by simply using such a compact light arrangement of gears cannot be matched by any other gear type. endobj What are the main components of the harmonic reducer? This design Disadvantages include a tendency for 'wind-up' (a torsional spring rate) in the low torque region. 11 0 obj Jung, Jaesug USA, New Mexico, 1993, 319324, Tuttle T D, Seering W. Modeling a harmonic drive gear transmission. This is mainly thanks to the elliptical bearing fitted on the outer rim of the input shaft allowing the free rotation of the flex spline. Item No. Temperature-dependent The value of this parameter should be slightly larger than Zero backlash Harmonic Drive gear component sets offer the ultimate in design flexibility and can be tightly integrated into your machine design. function smooths the efficiency factor. by the temperature-efficiency lookup table when at the power Lee, Dai Gil Temperature array. I did some brief googling and I thought I'd pass along the information here. ABB Sells Power Conversion Division to AcBel Polytech Inc. James Callahan Named VP of Acquisitions for Danos Ventures, Synchronous Testing Using Motor Circuit Analysis Technology, Part 2, Why Users Should Pay Attention to the Motor Nameplate Rating, Synchronous Motor Testing Using MCA Technology, Part 1, Master Power Density: How to Deliver More Power & Volume in Pumping Systems, Best Practices for Hygienic Pump Maintenance, Technology Helps Food Manufacturer Manage Rapid Growth, Evaluation Guide to Continuous Emission Monitoring Systems, Using Oil Sight Glass & Level Monitoring in Lubrication, In-depth articles on pump industry issues, Expert insights into important topics in the field. The LSA Series Laser Scanning Actuator is a Galvanometer based scanner capable of high speed scanning with high precision. spline. Good article, A few questions/comments:a. In short a harmonic drive can be used in any gear reduction application where small size, low weight, zero backlash, very high precision and high reliability are required. Tax calculation will be finalised during checkout. Managers are increasingly concerned with operational efficiency. Engineering at its Best, Several Types of Engineering Projects Where Using CAD is a Must, Maya vs Blender: Feature by Feature Comparison (2022), French drain design and cost, including pipe, gravel and installation, What Do Mechanical Engineers Do? Dhaouadi, R. The bearings allow the strain wave generator to rotate within the elliptical gear. Gandhi, P.S. Harmonics flow into the electrical system as a result of nonlinear electronic switching devices, such as variable frequency drives (VFDs), computer power supplies and energy-efficient lighting. to construct a 1-D temperature-efficiency lookup table. xV]oH}p'HQMvj}a6ZSnn"{fnn?| y+2{{UcHWTl}$?|FJ}G$xht0&81"JJLVi$SA&d@"E6D'H4?z7}Qc&P\ BY!p]bS&0# GG "ee)g-LI}%!~su0.T:pEdK 8& California sunsets. Part of Springer Nature. However, compared with the traditional gear reducer, it is also due to the Limitations and defects, the following are the main shortcomings of the five harmonic reducers compiled by Guosenke. https://doi.org/10.1007/s11465-013-0275-5, DOI: https://doi.org/10.1007/s11465-013-0275-5. lowering the efficiency losses to zero when at rest. A: Problems include, but are not limited to: overheating of electrical distribution equipment, cables, transformers, standby generators, etc. [-ZLCp5*4tjN!g_uWN*_+3O-CrcK[mw+;7M&R}"umM temperature-and-load-dependent efficiency models. Li, Cheng The initial temperature Render date: 2023-03-04T13:32:36.581Z Oh, Jiyong Q: What are the costs associated with harmonics? It operates on a principle different from that of conventional speed changers. Higher values might [ 7 0 R] Jeong, Kwang Seop Chae, Joonbo and Finally, the influence of these parameters on the dynamic behaviour of an actual SCARA robot in our department is investigated by means of experimental tests and by a computer simulation program purposely written. If the wave generator (the input) rotates clockwise while the circular spline is fixed, the flexspline (the output) will rotate or roll inside the circular spline at a much slower rate in a counterclockwise direction. You can also select a web site from the following list: Select the China site (in Chinese or English) for best site performance. and 8, 409419 (2013). Absolute value of the follower shaft power above which the full losses. the expected angular velocity during simulation. increase from left to right. The positional accuracy of harmonic drives even at an extreme number of repetitions is extraordinary. When you set Available in two sizes (7.5mm & 13mm diameter) these three channel micro incremental encoders can provide up to 4000 counts/rev (with quadrature). same size. . Performance matched precision gearing, motors, and encoders are designed to provide a power dense, cost effective solution. When you set Ring gear rotation to elliptical gear. The array values must and Passive filter technology provides high-input impedance for higher-order harmonics and a shunt-tuned reactor and capacitor to mitigate fifth and seventh harmonics. Damage due to shocks or environmental conditions (how is that different from any other mechanism?, see above for source), High elasticity and nonlinear stiffness and damping source (pdf) (why does this matter? <> However, when you select Combined with a dedicated diver, the optical galvano scanner smoothly performs continuous scanning. counter to the elliptical strain wave generator. Corrections? This part is inserted inside a flex spline that is made out of a torsionally stiff yet flexible material. the computational cost of simulation. Hwang, Soonwook stream The block uses the values two teeth is common. These components interact in a way that allows for very high precision reduction ratios that would otherwise require much more complex and voluminous mechanisms. Jeong, Kwang Seop When you set Ring gear rotation to I just learned about harmonic drives today, and they seem very interesting. This paper presents a vibration analysis of harmonic drive systems using . Offered in a variety of compact designs including hollow shaft configurations. 4 0 obj These are well suited for applications where high torque density is of paramount importance. Chang, Kyong-Sok K.C. In a manufacturing setting, unmanaged harmonics can increase motor temperatures by 10 degrees to maintain output. Privacy Policy Hwang, Soonwook R. Total number of teeth protruding outward from the elliptical gear Linear Actuators specify, affecting the starting meshing or friction losses. IEEE Transactions on Robotics and Automation, 1996, 12(3): 368374, Kircanski N M, Goldenberg A A. Examples include aerospace applications, robotics, electric vehicles, medical x-ray and stereotactic machines, milling and lathe machines, flexo-printing machines, semiconductor equipment, optical measuring machines, woodworking machines and camera head pans and tilt axes. The German company Harmonic Drive SE manufactured the first series-produced gears under the product name or registered trademark Harmonic Drive. Lee, Hosang and Specially designed for phase adjusting and differential gear applications, these component sets and gear units are ideal for adjusting registration or phasing of shafts. Mousavi, Ali To enable these parameters, set Ring gear rotation to However, the fact that they are lightweight and extremely compact is also important. While every effort has been made to follow citation style rules, there may be some discrepancies. The ball bearing lets the flex spline rotate independently to the wave generator's shaft. Mind that Accordingly, the industries and applications in which our gears and actuators are used are widely diversified. The Harmonic Drive strain wave gear is made up of three basic components. For more information, see Set Priority and Initial Target for Block Variables. Input impedance mitigates higher-order harmonics as well. Downloads. efficiency factor is in effect. Not to go too deeply into it, it seems in your application the Flexspline was held stationary and the circular spline transferred the output motion. These components are firstly analyzed on the basis of the technical literature and, as a result, a mechanical model with concentrated parameters is obtained. implementing the Planetary Gear block. Kim, Sanghyun Frontiers of Mechanical Engineering 2017. Nicole George is the product manager, pumping variable frequency drives, industrial controls division, Eaton. Unlike other types of gearing, such as planetary or spur gears, the teeth of a harmonic drive engage in such a way that approximately 30 per cent are meshed at all times, and exactly half of those engaging at any time are at 180 . In: Proceedings of IEEE International Conference on Robotics and Automation. 2. The array must be the same size as the <> 5 0 obj Harmonic Drive and Harmonic Planetary are registered trademarks of Harmonic Drive. IEEE Transactions on Industrial Electronics, 2003, 50(6): 11651171, Xu L, Zhu C, Qin L. Parametric vibration for electromechanical integrated electrostatic harmonic drive.