Change in Backlash of Humanoid Robot Joints under High Load

In this work, wear of reinforced poly-ether-ether-ketone (PEEK) polymer bushes in friction against 7075 aluminium alloy cam plates or titanium crankshafts is investigated in order to establish the application possibilities in transmission parts in humanoid robot joints under high load torque. The PEEK bush wear requires close examination as well as the input axis-output axis transmission error (backlash). Sliding wear tests were performed on bushes under 4000 kgfcm (392 Nm) load torque, while the cam plate oscillated in the humanoid robot leg joint evaluation system. The robot joint using PEEK bush achieved quite small backlash after the fatigue wear test.

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Measurement of Backlash and Fatigue Wear of PEEK Bush in Robot Joint under Middle Load

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.418.38 ◽

2013 ◽

Vol 418 ◽

pp. 38-43

Author(s):

Hitonobu Koike ◽

Kiyoto Itakura ◽

Shota Okazaki ◽

Masahiro Takamiya ◽

Kenji Kanemasu ◽

...

Keyword(s):

Evaluation System ◽

Humanoid Robot ◽

Transmission Error ◽

Fatigue Wear ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Ether Ketone ◽

Robot Leg ◽

Wear Tests ◽

Joint Evaluation

In order to establish the application possibilities in transmission parts in humanoid robot joints, wear of reinforced poly-ether-ether-ketone (PEEK) polymer bushes in friction against 7075 aluminium alloy cam plates is investigated. Additionally the transmission error (backlash) in robot joint was measured. The PEEK bush wear requires close examination as well as the input axis-output axis transmission error. Fatigue wear tests were performed on bushes under middle load at 3000 rpm motor speeds, while the cam plate oscillated in the humanoid robot leg joint evaluation system under 1300 kgfcm (132 Nm) load torque. The robot joint using PEEK bush achieved stable small backlash due to good friction perforance.

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Influence of Wear and Backlash on Machined PEEK Polymer Bushes and 7075 Aluminium Alloy Cam Plates Used in Robot Joints

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.157-158.1178 ◽

2012 ◽

Vol 157-158 ◽

pp. 1178-1185 ◽

Cited By ~ 3

Author(s):

Hitonobu Koike ◽

Katsuyuki Kida ◽

Kenji Kanemasu ◽

K. Itakura ◽

Kenichi Saruwatari ◽

...

Keyword(s):

Aluminium Alloy ◽

Humanoid Robot ◽

Transmission Error ◽

Load Range ◽

Joint System ◽

System A ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Movement Ability ◽

Number Of Cycles

Due to constant exposure to high torque and loads toughness, compressive durability and light weight of joint parts are crucial factors for biped walking humanoid robot parts. When polymer transmission parts are used for the manufacture of humanoid robot joint, wear becomes an important factor in terms of transmission error (backlash) between the input and output axes, ex. between the motor and the robot’s leg joint. In such joint system, a polymer bushes is directly connected to a cam plate, playing an important role in the robot's movement ability. In this work, the influence of wear of reinforced poly-ether-ether-ketone (PEEK) polymer bushes in friction against 7075 aluminium alloy cam plates is investigated in order to establish the application possibilities in transmission parts in humanoid robot’s joint. The PEEK bush surface conditions as well as the input axis-output axis backlash require close examination, so that efficient systems can be built. Sliding wear tests were performed on bushes under 0-50kgfcm loaded torque while the cam plate oscillated. Based on the wear observation, it was found that in a high load range the backlash increased along with number of cycles due to PEEK bush wear. The bush surface roughness also increased during testing. Roughness of PEEK bush surface and the loaded torque for output axis were significantly related to backlash of output axis in robot joint.

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Wear and Transmission Error between PEEK Bush and 7075 Aluminium Alloy Cam Plate Components in Robot Joints

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.307.3 ◽

2013 ◽

Vol 307 ◽

pp. 3-8 ◽

Cited By ~ 3

Author(s):

Hitonobu Koike ◽

Kenji Kanemasu ◽

K. Itakura ◽

Kenichi Saruwatari ◽

Justyna Rozwadowska ◽

...

Keyword(s):

Aluminium Alloy ◽

Sliding Wear ◽

Humanoid Robot ◽

Transmission Error ◽

Carbon Fibres ◽

Surface Conditions ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Ether Ketone ◽

Wear Tests

In this work, wear of reinforced poly-ether-ether-ketone (PEEK containing PTFE, graphite and carbon fibres) polymer bushes in friction against 7075 aluminium alloy cam plates is investigated in order to establish the application possibilities in transmission parts in humanoid robot joints. The PEEK bush surface conditions as well as the input axis-output axis transmission error (backlash) require close examination. Sliding wear tests were performed on bushes under 900 kgfcm loaded torque, while the cam plate oscillated. Based on the wear observation, it was found that PEEK wear fragments in the interface between PEEK bush and aluminium alloy cam plate formed a PEEK film.

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Preparation and Tribological Behaviors of Lubrication-Enhanced PEEK Composites

Applied Sciences ◽

10.3390/app10217536 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7536

Author(s):

Yutao Yan ◽

Cheng Jiang ◽

Yuqiu Huo ◽

Chaofeng Li

Keyword(s):

Tensile Strength ◽

Graphene Oxide ◽

Adhesive Wear ◽

Hot Isostatic Pressing ◽

Fatigue Wear ◽

Pressing Method ◽

Tribological Behaviors ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Ether Ketone

Poly-ether-ether ketone (PEEK) is a great potential thermoplastic in industry and medical treatment and health. In this work, PEEK/graphene oxide (GO) and PEEK/MoS2 composites were prepared by a novel hot isostatic pressing method. The addition of GO alters the tribological behaviors mechanism; fatigue wear mechanism is predominant to PEEK/GO composites. However, the combination of abrasive and adhesive wear mechanisms is observed for PEEK/MoS2 composites and PEEK. The reason for this is that the hardness and tensile strength of composites are increased with the appropriate addition of GO. The response time to stable friction state of PEEK/GO and PEEK/MoS2 composites is reduced in comparison with PEEK, which is conducive to shorten running-in time, reduce the energy consumption, and improve the tribological performances of composites. The addition of GO and MoS2 can effectively decrease the friction coefficient and wear rate, and the optimal content of GO and MoS2 was 0.7 wt.% and 15 wt.%, respectively. The results indicate that PEEK/GO and PEEK/MoS2 are impressive composites that possess super tribological properties.

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Measurement of Joint Element Transmission Error in a Humanoid Walking Robot

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.566.348 ◽

2012 ◽

Vol 566 ◽

pp. 348-352 ◽

Cited By ~ 4

Author(s):

Kiyoto Itakura ◽

Hitonobu Koike ◽

Katsuyuki Kida ◽

Kenji Kanemasu

Keyword(s):

Humanoid Robots ◽

Power Input ◽

Transmission Error ◽

Error Measurement ◽

Harmonic Drive ◽

Walking Robot ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Joint Element ◽

Ether Ketone

In the present work, a prototype of a joint element to be used in lightweight and compact joints for tall humanoid robots is investigated. The newly developed element consists of a harmonic drive gearing device, a multi axis mechanism and a resin bush. Bushes produced from two kinds of bush materials: poly-ether-ether-ketone (PEEK) and polyacetal (POM) were tested. Furthermore, two testing machines to evaluate the joints were constructed: for the power input-output transmission error measurement and for the investigation of the influence of walking-load on bush wear.

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Effects of sequential He+ and Ar+ implantation on surface properties of polymers

Journal of Materials Research ◽

10.1557/jmr.1996.0335 ◽

1996 ◽

Vol 11 (10) ◽

pp. 2661-2667 ◽

Cited By ~ 28

Author(s):

Gopal R. Rao ◽

Eal H. Lee

Keyword(s):

Wear Resistance ◽

Surface Properties ◽

Ion Irradiation ◽

Surface Hardness ◽

Wear Test ◽

Surface Region ◽

Near Surface ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Hardness Increase

Three important polymers: polystyrene (PS), poly ether ether ketone (PEEK), and polyimide Kapton, were irradiated separately with 1 MeV He+, 1 MeV Ar+, and 1 MeV He+ followed by 1 MeV Ar+ sequentially, to a fluence of 3 × 1019 ions/m2 for each ion. The specimens were characterized for changes in surface hardness using a nanoindentation technique, and wear resistance using a reciprocating sliding wear apparatus with a steel ball counterface. Results indicated that while all polymers showed higher hardness values after ion irradiation, the dual irradiation resulted in the largest hardness increase, greater than for the single ion-irradiated specimens. Wear test results also indicated that the dual He+ + Ar+ irradiation resulted in the best improvement in wear resistance of the polymers. These improvements in properties are a consequence of cross-linking of the polymer material caused by the ion irradiation. Linear energy transfer considerations showed that the dual He+ + Ar+ implantation was better because it combined a deeper implant, in the form of He, along with Ar irradiation which resulted in a shallower but more highly cross-linked layer at the near surface. Thus a deeper and graded cross-linked surface region was formed. The study shows that there is greater flexibility for tailoring surface properties of polymers by using a judicious combination of ion species, ion energies, and fluences.

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Preparation and Tribological Behaviours of Lubrication Enhanced PEEK Composites

10.20944/preprints202009.0438.v1 ◽

2020 ◽

Author(s):

Yutao Yan ◽

Cheng Jiang ◽

Yuqiu Huo ◽

Chaofeng Li

Keyword(s):

Tensile Strength ◽

Energy Consumption ◽

Adhesive Wear ◽

Hot Isostatic Pressing ◽

Fatigue Wear ◽

Pressing Method ◽

Ether Ether Ketone ◽

Poly Ether Ether Ketone ◽

Ether Ketone ◽

Reduce Energy Consumption

Poly-ether-ether ketone (PEEK) is a great potential thermoplastic in industry and medical treatment and health. In this work, the PEEK/GO and PEEK/MoS2 composites were prepared by a novel hot isostatic pressing method. The addition of GO alters the tribological behaviours mechanism, fatigue wear mechanism is predominant to PEEK/GO composites. However, the combination of abrasive and adhesive wear mechanisms is observed for PEEK/MoS2 composites and PEEK. The reason is the hardness and tensile strength of composites are increased with the appropriate addition of GO. The response time to stable friction state of PEEK/GO and PEEK/MoS2 composites reduces in compared with PEEK, which conduce to shorten running-in time, reduce energy consumption and improve the tribological performances of composites. The addition of GO and MoS2 can effectively decrease the friction coefficient and wear rate, and the optimal content of GO and MoS2 was 0.7 wt.% and 15 wt.%, respectively. The results indicate that PEEK/GO and PEEK/MoS2 are impressive composites that possess super tribological properties.

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