Low-cost variable stiffness joint design using translational variable radius pulleys

Yiğit, Cihat Bora; Bayraktar, Ertuğrul; Boyraz, Pınar

doi:10.1016/j.mechmachtheory.2018.08.006

Cited by 21 publications

(6 citation statements)

References 28 publications

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“…Therefore, the application of low-cost sensor-based HAR methods has become more prominent in this field. Yigit et al [8]. proposed three comprehensive algorithms for low-cost variable stiffness robotics mechanisms.…”

Section: Related Workmentioning

confidence: 99%

“…The attitude angle calculation procedure begins with the initialization process and unit conversion of acceleration data (lines 1-2). Subsequently, Euler angles are computed based on the sampled frequency-processing sequence data, with compensation provided through gyroscope and accelerometer data (lines [3][4][5][6][7][8][9][10][11][12]. Following this, the Euler angle vector is transformed into a rotation matrix, and from there into a quaternion and Rodrigues parameters (lines [13][14][15].…”

Section: Attitude Angle Calculation Algorithm Designmentioning

confidence: 99%

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A Hybrid Human Activity Recognition Method Using an MLP Neural Network and Euler Angle Extraction Based on IMU Sensors

Mao,

Yan,

Guo

et al. 2023

Applied Sciences

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Inertial measurement unit (IMU) technology has gained popularity in human activity recognition (HAR) due to its ability to identify human activity by measuring acceleration, angular velocity, and magnetic flux in key body areas like the wrist and knee. It has propelled the extensive application of HAR across various domains. In the healthcare sector, HAR finds utility in monitoring and assessing movements during rehabilitation processes, while in the sports science field, it contributes to enhancing training outcomes and preventing exercise-related injuries. However, traditional sensor fusion algorithms often require intricate mathematical and statistical processing, resulting in higher algorithmic complexity. Additionally, in dynamic environments, sensor states may undergo changes, posing challenges for real-time adjustments within conventional fusion algorithms to cater to the requirements of prolonged observations. To address these limitations, we propose a novel hybrid human pose recognition method based on IMU sensors. The proposed method initially calculates Euler angles and subsequently refines them using magnetometer and gyroscope data to obtain the accurate attitude angle. Furthermore, the application of FFT (Fast Fourier Transform) feature extraction facilitates the transition of the signal from its time-based representation to its frequency-based representation, enhancing the practical significance of the data. To optimize feature fusion and information exchange, a group attention module is introduced, leveraging the capabilities of a Multi-Layer Perceptron which is called the Feature Fusion Enrichment Multi-Layer Perceptron (GAM-MLP) to effectively combine features and generate precise classification results. Experimental results demonstrated the superior performance of the proposed method, achieving an impressive accuracy rate of 96.13% across 19 different human pose recognition tasks. The proposed hybrid human pose recognition method is capable of meeting the demands of real-world motion monitoring and health assessment.

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Section: Related Workmentioning

confidence: 99%

Section: Attitude Angle Calculation Algorithm Designmentioning

confidence: 99%

A Hybrid Human Activity Recognition Method Using an MLP Neural Network and Euler Angle Extraction Based on IMU Sensors

Mao,

Yan,

Guo

et al. 2023

Applied Sciences

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“…Spring-based static balancing mechanisms offer the advantage of lower overall mass and inertia compared to counterbalancing, making them an attractive option for safety, but come at the cost of higher design and modeling complexity. Spring-based static balancing methods have mostly fallen into three categories: 1) springloaded linkages [8][9][10][11][12][13][14], 3) cams with spring-loaded followers [15][16][17][18][19], and 3) and wire-wrapped cams [20][21][22][23][24][25][26][27][28][29][30][31]. Additionally, many simple balancing mechanisms are presented in [32].…”

Section: Relevant Work and Summary Of Limitationsmentioning

confidence: 99%

Design Considerations and Robustness to Parameter Uncertainty in Wire-Wrapped Cam Mechanisms

Johnston

Orekhov

Simaan

2023

Journal of Mechanisms and Robotics

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Collaborative robots must simultaneously be safe enough to operate in close proximity to human operators and powerful enough to assist users in industrial tasks such as lifting heavy equipment. The requirement for safety necessitates that collaborative robots are designed with low-powered actuators. However, some industrial tasks may require the robot to have high payload capacity and/or long reach. For collaborative robot designs to be successful, they must find ways of addressing these conflicting design requirements. One promising strategy for navigating this tradeoff is through the use of static balancing mechanisms to offset the robot's self weight, thus enabling the selection of lower-powered actuators. In this paper, we introduce a novel, 2 degree of freedom static balancing mechanism based on spring-loaded, wire-wrapped cams. We also present an optimization-based cam design method that guarantees the cams stay convex, ensures the springs stay below their extensions limits, and minimizes sensitivity to unmodeled deviations from the nominal spring constant. Additionally, we present a model of the effect of friction between the wire and the cam. Lastly, we show experimentally that the torque generated by the cam mechanism matches the torque predicted in our modeling approach. Our results also suggest that the effects of wire-cam friction are significant for non-circular cams.

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“…The profile curves of the variable radius of pulleys were optimized and synthesized. 17 Most variable-stiffness mechanisms use springs or spring plates that are easy to manufacture and inexpensive. For the variable stiffness mechanism with a special surface, it is necessary to design the surface contour according to the stiffness requirements of specific application scenarios in practical application, which limits the rapid stiffness reconstruction capability of the joint actuator.…”

Section: Introductionmentioning

confidence: 99%

Mechanical design and analysis of a reconfigurable variable stiffness mechanism based on permanent magnetic springs and swing guide mechanism

Sun

Zhao

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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Stiffness control of an actuator is important to ensure stable contact motion and collision safety for human-robot integration tasks. The variable stiffness mechanism (VSM) is an important part of the variable stiffness actuator. We propose a novel reconfigurable rotational VSM that uses magnet springs and swing guide mechanisms in this paper. Magnet springs are used as elastic elements that are driven by the cable, and the initial stiffness of the mechanism can be regulated by adjusting the air gap distance between the magnets. The mathematical stiffness model of the VSM is developed, and the numerical calculation simulation and experiments are conducted to verify the feasibility of the proposed VSM.

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Low-cost variable stiffness joint design using translational variable radius pulleys

Cited by 21 publications

References 28 publications

A Hybrid Human Activity Recognition Method Using an MLP Neural Network and Euler Angle Extraction Based on IMU Sensors

A Hybrid Human Activity Recognition Method Using an MLP Neural Network and Euler Angle Extraction Based on IMU Sensors

Design Considerations and Robustness to Parameter Uncertainty in Wire-Wrapped Cam Mechanisms

Mechanical design and analysis of a reconfigurable variable stiffness mechanism based on permanent magnetic springs and swing guide mechanism

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