scholarly journals Analysis and optimization of the wall-climbing robot with an adsorption system and adhesive belts

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092640
Author(s):  
Jinfu Liu ◽  
Linsen Xu ◽  
Jiajun Xu ◽  
Lei Liu ◽  
Gaoxin Cheng ◽  
...  
Keyword(s):  
High Stability ◽  
Operating Conditions ◽  
Brick Wall ◽  
Adsorption System ◽  
Exterior Wall ◽  
Climbing Robot ◽  
Ceramic Brick ◽  
Attachment Mechanism ◽  
Safe Operating ◽  
Moving Speed

This article presents an innovative wall-climbing robot for detection on smooth wall surfaces, which consists of a vacuum adsorption system and adhesion belts, making the robot flexible and effectively steerable. Moreover, the detailed attachment mechanism is further analyzed for the climbing tasks. Safe operating conditions, kinematics, and dynamic model are derived, respectively, indicating that at least the adsorption force of 30 N and the motor torque of 2 N·m are required for stable climbing of the robot. Furthermore, the prototype of the wall-climbing robot is manufactured and the climbing abilities are tested on various wall surfaces showing that the maximum moving speed and corresponding load are 7.11 cm/s and 0.8 kg on the concrete exterior wall, 5.9 cm/s and 0.75 kg on the ceramic brick wall, 6.09 cm/s and 0.85 kg on the lime wall, and 5.9 cm/s and 1 kg on the acrylic surface, respectively, which demonstrates that the robot has high stability and adaptability.

Recent Advances in Lower Bound Shakedown Analysis

2009 ◽  
Author(s):  
Dieter Weichert ◽  
Abdelkader Hachemi
Keyword(s):  
Finite Element ◽  
Lower Bound ◽  
Process Engineering ◽  
Operating Conditions ◽  
Structural Elements ◽  
Shakedown Analysis ◽  
Material Models ◽  
Practical Engineering ◽  
Safe Operating ◽  
New Algorithms

The special interest in lower bound shakedown analysis is that it provides, at least in principle, safe operating conditions for sensitive structures or structural elements under fluctuating thermo-mechanical loading as to be found in power- and process engineering. In this paper achievements obtained over the last years to introduce more sophisticated material models into the framework of shakedown analysis are developed. Also new algorithms will be presented that allow using the addressed numerical methods as post-processor for commercial finite element codes. Examples from practical engineering will illustrate the potential of the methodology.

Morphological Adaptation for Speed Control of Pipeline Inspection Gauges MC-PIG

2021 ◽  
Author(s):  
Sujet Phodapol ◽  
Tachadol Suthisomboon ◽  
Pong Kosanunt ◽  
Ravipas Vongasemjit ◽  
Petch Janbanjong ◽  
...  
Keyword(s):  
Fluid Velocity ◽  
Operating Conditions ◽  
Pi Control ◽  
Operating Pressure ◽  
Acceptable Error ◽  
Valve Unit ◽  
Pipeline Inspection ◽  
Flow Adjustment ◽  
Valve Angle ◽  
Moving Speed

Abstract Passive and active hybrid pipeline inspection gauges (PIGs) have been used for in-pipe inspection. While a passive PIG cannot control its speed, the hybrid version can achieve this by using an integrated valve specifically designed and embedded in the PIG. This study proposes a generic new method for speed adaptation in PIGs (called MC-PIG) by introducing a generic, modular, controllable, external valve unit add-on for attaching to existing conventional (passive) PIGs with minimal change. The MC-PIG method is based on the principle of morphological computation with closed-loop control. It is achieved by regulating/computing the PIG's morphology (i.e., a modular rotary valve unit add-on) to control bypass flow. Adjustment of the valve angle can affect the flow rate passing through the PIG, resulting in speed regulation ability. We use numerical simulation with computational fluid dynamics (CFD) to investigate and analyze the speed of a simulated PIG with the valve unit adjusted by proportional-integral (PI) control under various in-pipe pressure conditions. Our simulation experiments are performed under different operating conditions in three pipe sizes (16″, 18″, and 22″ in diameter) to manifest the speed adaptation of the PIG with the modular valve unit add-on and PI control. Our results show that the PIG can effectively perform real-time adaptation (i.e., adjusting its valve angle) to maintain the desired speed. The valve design can be adjusted from 5 degrees (closed valve, resulting in high moving speed) to a maximum of 45 degrees (fully open valve, resulting in low moving speed). The speed of the PIG can be regulated from 0.59 m/s to 3.88 m/s in a 16″ pipe at 4.38 m/s (in-pipe fluid velocity), 2500 kPa (operating pressure), and 62 °C (operating temperature). Finally, the MC-PIG method is validated using a 3D-printed prototype in a 6″ pipe. Through the investigation, we observed that two factors influence speed adaptation; the pressure drop coefficient and friction of the PIG and pipeline. In conclusion, the results from the simulation and prototype show close characteristics with an acceptable error.

scholarly journals Enhanced dynamic voltage clamping capability of Clustered IGBT at turn-off period

2016 ◽  
Vol 29 (1) ◽  
pp. 1-10
Author(s):  
Hong Long ◽  
Mark Sweet ◽  
Sankara Narayanan
Keyword(s):  
Numerical Evaluation ◽  
Load Condition ◽  
Operating Conditions ◽  
Current Gain ◽  
Power Devices ◽  
Inductive Load ◽  
Dynamic Voltage ◽  
Voltage Clamping ◽  
Safe Operating ◽  
Off Time

One of the critical requirements for high power devices is to have rugged and reliable capability against hash operating conditions. In this paper, we present the dynamic voltage clamping capability of 3.3kV Field Stop Clustered IGBT devices under extreme inductive load condition. It shows that PMOS trench gate CIGBT structure with outstanding performance of fast turn-off time and low over-shoot voltage. Further optimization of current gain of CIGBT structure is analyzed through numerical evaluation. A step further in the safe operating area has been achieved for high voltage devices by CIGBT technology.

scholarly journals Safe operating conditions for NSLS-II Storage Ring Frontends commissioning

2015 ◽  
Author(s):  
S. Seletskiy ◽  
C. Amundsen ◽  
K. Ha ◽  
A. Hussein
Keyword(s):  
Storage Ring ◽  
Operating Conditions ◽  
Safe Operating

Safe Operating Conditions to Prevent Damage in Ni-YSZ Anode Supported SOFC

2019 ◽  
Vol 35 (1) ◽  
pp. 1571-1579 ◽  
Author(s):  
Virginie Roche ◽  
Claude Roux ◽  
Marlu Cesar Steil
Keyword(s):  
Operating Conditions ◽  
Safe Operating

Contacting Surface-Transfer Control for Reconfigurable Wall-Climbing Robot Gunryu III

2013 ◽  
Vol 25 (3) ◽  
pp. 439-448 ◽  
Author(s):  
Woosub Lee ◽  
◽  
Shigeo Hirose ◽  
Keyword(s):  
High Stability ◽  
Control Strategies ◽  
High Mobility ◽  
Climbing Robot ◽  
Climbing Robots ◽  
Simulation Experiments ◽  
Contact Mode ◽  
Magnetic Device ◽  
New Type ◽  
Motion Strategy

For the wall-climbing robots, high mobility as well as stability on the surface of the walls are the most important features. To achieve these features, this paper proposes a new type of reconfigurable arm equipped multi module wall-climbing robot named Gunryu III. Gunryu III has the potential ability to generate high stability and high mobility by using its arm to connect multiple mobile modules together and a magneticforce-changeable adsorption device. One of the important motions of the reconfigurable wall-climbing robot Gunryu III is surface-transfer motion, which is to change from one moving surface to another, such as from floor to wall and wall to ceiling. In this paper, we propose a new surface-transfer motion strategy named Contact Mode. It is to make surface-transfer motion by contacting some part of the moving module to one of the surfaces. As for the Contact Mode surfacetransfer motion, we first conduct several fundamental discussions, such as the five basic types of motion, conditions for making contact between the mobile module and the wall, effective way of using the magnetic device and two criteria of the evaluation. We then quantitatively evaluate the effectiveness of the proposed Contact Mode surface-transfer motion using simulation experiments, and clarify basic optimized control strategies.

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