scholarly journals Rugged and Compact Three-Axis Force/Torque Sensor for Wearable Robots

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2770
Author(s):  
Heeyeon Jeong ◽  
Kyungjun Choi ◽  
Seong Jun Park ◽  
Cheol Hoon Park ◽  
Hyouk Ryeol Choi ◽  
...  
Keyword(s):  
Simple Structure ◽  
Load Capacity ◽  
Artificial Muscle ◽  
High Load ◽  
Torque Sensor ◽  
Wearable Robot ◽  
Wearable Robots ◽  
Negative Electrodes ◽  
The Difference ◽  
High Load Capacity

In the field of robotics, sensors are crucial in enabling the interaction between robots and their users. To ensure this interaction, sensors mainly measure the user’s strength, and based on this, wearable robots are controlled. In this paper, we propose a novel three-axis force/torque sensor for wearable robots that is compact and has a high load capacity. The bolt and nut combination of the proposed sensor is designed to measure high-load weights, and the simple structure of this combination allows the sensor to be compact and light. Additionally, to measure the three-axis force/torque, we design three capacitance-sensing cells. These cells are arranged in parallel to measure the difference in capacitance between the positive and negative electrodes. From the capacitance change measured by these sensing cells, force/torque information is converted through deep neural network calibration. The sensing point can also be confirmed using the geometric and kinematic relation of the sensor. The proposed sensor is manufactured through a simple and inexpensive process using cheap and simply structured components. The performance of the sensor, such as its repeatability and capacity, is evaluated using several experimental setups. In addition, the sensor is applied to a wearable robot to measure the force of an artificial muscle.

scholarly journals Design and Performance of Nonlinear Control for an Electro-Hydraulic Actuator Considering a Wearable Robot

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 389 ◽  
Author(s):  
Song ◽  
Lee ◽  
Park ◽  
Baek
Keyword(s):  
Sliding Mode ◽  
Load Capacity ◽  
High Energy ◽  
Adaptive Sliding Mode Control ◽  
Hydraulic Systems ◽  
Hydraulic Actuator ◽  
Wearable Robot ◽  
Wearable Robots ◽  
And Performance ◽  
High Load Capacity

In the development of a wearable robot, compact volume size, high energy efficiency, and a high load capacity linear actuator system are necessary. However, conventional hydraulic actuator systems are difficult to apply to wearable robots. Also, they have nonlinearities because of the presence of hydraulic fluid in a single rod cylinder. Electric linear actuators resolve the problems of hydraulic systems. However, due to their low load capacity, they are not easy to apply to wearable robots. In this paper, a pump-controlled electro-hydraulic actuator (EHA) system that considers the disadvantages of the hydraulic actuator and electric actuator is proposed for a wearable robot. Initially, a locking circuit design is considered for the EHA to give the system load holding capacity. Based on the developed model, the adaptive sliding mode control (ASMC) scheme is designed to resolve the nonlinearity problem of changes in the dynamic system. The ASMC scheme is then modeled and verified with Simulink. In order to verify the performance of the proposed adaptive control with the model, experiments are conducted. The proposed EHA verifies that the ASMC reaches the target value well despite the existence of many model uncertainties.

An Air Layer Modeling Approach for Air and Air/Vacuum Bearings

1997 ◽  
Vol 119 (3) ◽  
pp. 388-392
Author(s):  
J. M. Pitarresi ◽  
K. A. Haller
Keyword(s):  
Load Capacity ◽  
Load Resistance ◽  
High Load ◽  
Air Bearing ◽  
Air Bearings ◽  
Bearing Surface ◽  
Know How ◽  
Modeling Approach ◽  
Vibrational Characteristics ◽  
High Load Capacity

Air layer supported bearing pads, or “air bearings” as they are commonly called, are popular because of their high load capacity and low in-plane coefficient of friction, making them well suited for supporting moving, high accuracy manufacturing stages. Air/vacuum bearings enhance these capabilities by giving the bearing pad load resistance capacity in both the upward and downward directions. Consequently, it is desirable to know how to model the air layer between the bearing pad and the bearing surface. In this paper, a simple finite element modeling approach is presented for investigating the vibrational characteristics of an air layer supported bearing. It was found that by modeling the air layer as a bed of uniform springs who’s stiffness is determined by load-displacement tests of the bearing, a reasonable representation of the response can be obtained. For a bearing supported by air without vacuum, the dynamic response was very similar to that of a freely supported bearing. The addition of vacuum to an air bearing was found to significantly lower its fundamental frequency which could lead to unwanted resonance problems.

A one-stage, high-load capacity separation actuator using anti-friction rollers and redundant shape memory alloy wires

2015 ◽  
Vol 86 (12) ◽  
pp. 125005 ◽  
Author(s):  
Yan Xiaojun ◽  
Huang Dawei ◽  
Zhang Xiaoyong ◽  
Liu Ying ◽  
Yang Qiaolong
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Load Capacity ◽  
High Load ◽  
One Stage ◽  
High Load Capacity

scholarly journals Analysis of the geometry and contact density of globoid gearing

2020 ◽  
Vol 329 ◽  
pp. 03008
Author(s):  
Aleksandr Vyatkin
Keyword(s):  
Numerical Methods ◽  
Load Capacity ◽  
High Load ◽  
Design Stage ◽  
Energy Losses ◽  
Technological Parameters ◽  
Contact Density ◽  
Small Energy ◽  
Worm Gears ◽  
High Load Capacity

Globoid worm gears have been widely applied in a range of technological branches in which other types of worm gears are less effective. The main functional indicators which facilitated their popularity include high load capacity and durability, low vibroactivity and small energy losses. As the experience of application and the results of the study of globoid worm gears showed, the level of operational properties of globoid gears is higher than that of the others only if the gearing and technological parameters of their manufacturing are optimally chosen during the design stage. This paper describes a method for estimating the gearing parameters of a globoid gear with an account of the geometry of the elements (the geometry of the teeth of the wheel and the worm thread), namely the calculation of the gap fields in the globoid gearing by means of numerical methods.

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