Development of 3-DOF Soft Manipulator with ER Fluid Clutches

Recently, as robots and humans have increasingly come to share common space, especially in the fields of medical and home automation, it has become necessary to consider the frequent physical collision of robots and environments (e.g. humans). However, many robot joints employ actuators with high-ratio gear trains, and therefore, when this type of robot comes into contact with a human, physical pain may be caused. This study deals with the development of a manipulator using a smart flexible joint employing ER fluid and a pneumatic cushion that has a sensor function. In addition, position control and collision experiments were performed with the developed manipulator. The experimental results demonstrate the effectiveness of the manipulator.

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Preliminary Analysis of a Lightweight and Deployable Soft Robot for Space Applications

Applied Sciences ◽

10.3390/app11062558 ◽

2021 ◽

Vol 11 (6) ◽

pp. 2558

Author(s):

Mario Troise ◽

Matteo Gaidano ◽

Pierpaolo Palmieri ◽

Stefano Mauro

Keyword(s):

Preliminary Analysis ◽

Inverse Kinematics ◽

Control Algorithm ◽

Dynamic Models ◽

Robotic Systems ◽

Inflation Pressure ◽

Space Applications ◽

Space Industry ◽

Rigid Body Model ◽

Soft Manipulator

The rising interest in soft robotics, combined to the increasing applications in the space industry, leads to the development of novel lightweight and deployable robotic systems, that could be easily contained in a relatively small package to be deployed when required. The main challenges for soft robotic systems are the low force exertion and the control complexity. In this manuscript, a soft manipulator concept, having inflatable links, is introduced to face these issues. A prototype of the inflatable link is manufactured and statically characterized using a pseudo-rigid body model on varying inflation pressure. Moreover, the full robot model and algorithms for the load and pose estimation are presented. Finally, a control strategy, using inverse kinematics and an elastostatic approach, is developed. Experimental results provide input data for the control algorithm, and its validity domain is discussed on the basis of a simulation model. This preliminary analysis puts the basis of future advancements in building the robot prototype and developing dynamic models and robust control.

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Coating of Polyaniline with an Insulating Polymer to Improve the Power Efficiency of Electrorheological Fluids

International Journal of Modern Physics B ◽

10.1142/s0217979299001983 ◽

1999 ◽

Vol 13 (14n16) ◽

pp. 1931-1939 ◽

Cited By ~ 9

Author(s):

J. Akhavan ◽

K. Slack ◽

V. Wise ◽

H. Block

Keyword(s):

Power Efficiency ◽

Electrorheological Fluids ◽

Emeraldine Base ◽

Heavy Duty ◽

Base Form ◽

Static Yield ◽

High Fields ◽

Er Fluids ◽

Er Fluid ◽

A Current

Currents drawn under high fields often present practical limitations to electrorheological (ER) fluids usefulness. For heavy-duty applications where large torques have to be transmitted, the power consumption of a ER fluid can be considerable, and for such uses a current density of ~100μ A cm -2 is often taken as a practical upper limit. This investigation was conducted into designing a fluid which has little extraneous conductance and therefore would demand less current. Selected semi-conducting polymers provide effective substrates for ER fluids. Such polymers are soft insoluble powdery materials with densities similar to dispersing agents used in ER formulations. Polyaniline is a semi-conducting polymer and can be used as an effective ER substrate in its emeraldine base form. In order to provide an effective ER fluid which requires less current polyaniline was coated with an insulating polymer. The conditions for coating was established for lauryl and methyl methacrylate. Results from static yield measurements indicate that ER fluids containing coated polyaniline required less current than uncoated polyaniline i.e. 0.5μ A cm -2. The generic type of coating was also found to be important.

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