Control of Low-Cost Customizable Robot Arm Actuated by Elastic Tendons

2016 ◽  
Vol 28 (4) ◽  
pp. 509-522 ◽  
Author(s):  
Junki Togashi ◽  
◽  
Kazuhisa Mitobe ◽  
Genci Capi ◽  
Keyword(s):  
Force Control ◽  
Control Method ◽  
Low Cost ◽  
String Tension ◽  
Machining Accuracy ◽  
Robot Arm ◽  
Compliant Joints ◽  
Low Stiffness ◽  
Static Conditions ◽  
The Cost

[abstFig src='/00280004/09.jpg' width='300' text='Elastic tendon driven robot arm' ] This paper presents a low-cost, lightweight robot arm with very low stiffness actuated by elastic tendons. To simplify the string tension control, a new winding device was developed. Small pulleys were incorporated into the winding drum to reduce friction between the tendon and the drum. A marionette-style two-link robot arm with compliant joints was prototyped. Because the arm and winding devices were separate from each other, the cost and weight of the robot were reduced. The links are made with lightweight wood connected by simple shaft joints. The robot design can be easily modified by the user because the mechanical parts do not require high machining accuracy. This robot is intended for implementation in tasks that do not require high positioning accuracy using a simple force control under environmental constraints. Because of its low stiffness, simple and sensor-less force control can be easily implemented based on the relationship between forces under static conditions. The proposed simple control method was evaluated experimentally by conducting position, static force, and hybrid position/force control tasks and was shown to perform well. The results also demonstrate that employing additional sensors, such as a camera, improves the accuracy of the controller.

scholarly journals DEVELOPMENT OF DEVICE FOR RESTORATION OF PLACES FOR BEARINGS

2021 ◽  
pp. 133-138
Author(s):  
Ludmila Shvets
Keyword(s):  
Contact Area ◽  
Low Cost ◽  
Cost Effective ◽  
Metal Corrosion ◽  
Machining Accuracy ◽  
Electrospark Coating ◽  
High Productivity ◽  
Technical Requirements ◽  
Coating Method ◽  
The Cost

Defects of case details include operation of openings under bearings within 0,2 - 0,4 mm on the party, operation of landing belts under sleeves. When restoring them, traditional methods are used: installation of repair bushings, application of polymer and electrolytic coatings, micron smelting, electrospark treatment, etc. Restored parts must have hardness and wear resistance with the parameters of the material of the reducing part (deviation 10 - 15%), have sufficient adhesion to the base metal, corrosion resistance in a humid environment, provide maximum contact area with the conjugate part, no pores, slag, foreign inclusions . The method of restoration must eliminate the thermal impact on the part and be cost-effective. Polymer compositions are usually brittle, subject to breakage and leaching. Surfacing causes warping of the part, bleaching of cast iron, the formation of slag and pores in the deposited layer. The electrospark coating method does not provide sufficient contact area with the conjugate part. The use of electrolytes for iron seats in some enterprises is aggressive, unstable, requires heating or the use of expensive thyristor power supplies, followed by machining, as the microhardness of precipitation reaches a large value depending on the composition of the electrolyte and process modes, have high internal voltage. The proposed device for restoring the bearings simplifies the existing method and meets the technical requirements of manufacturers in terms of machining accuracy (ovality, taper, coaxiality and surface roughness), provides high productivity (2 times higher than the productivity of specialized machines horizontally). and low cost (60 times lower than the cost of specialized machines).

Robot Manipulator Vibration Resistance Control Based on Physical Model

2020 ◽  
Author(s):  
Ting-Sheng Chen ◽  
Jen-Yuan (James) Chang
Keyword(s):  
Control Method ◽  
Robot Manipulator ◽  
Path Following ◽  
Position Error ◽  
Machining Accuracy ◽  
Robot Arm ◽  
End Effector ◽  
Vibration Resistance ◽  
Mass Spring ◽  
Accuracy And Repeatability

Abstract The overwhelming manufacturing process with robotic arm has replaced human labors in handling and manufacturing work-pieces in factories. In these years, higher accuracy and repeatability are required for robotic manipulators to perform processes such as welding, deburring and grinding in factories. In these path-following processes, the manipulator’s end-effector often encounter position error caused by its vibrating structures. Therefore, the quality of machining accuracy and surface roughness becomes unstable and unsatisfied. For the purpose of avoiding the vibrations to occur in the robotic manipulator, this study aims to design a control method to reduce vibrations which is divided into two parts, namely (1) dynamic modeling the robot arm by applying modified mass-spring-damper model to each joints and links of the robot arm, and (2) realizing the control of the robot arm’s vibration resistance with predicated dynamics to compensate for the undesired dynamics, respectively. Through the proposed model, the response of each joints in different postures and different payloads applied at the end effector can be fully analyzed and the vibrations can be predicted and compensated. Results with the proposed vibration resistance control method indicate improvement of the model robot arm’s dynamic position error.

Study of the control process and fabrication of microstructures using a tip-based force control system

2016 ◽  
Vol 232 (11) ◽  
pp. 1928-1942 ◽  
Author(s):  
Jingran Zhang ◽  
Yongda Yan ◽  
Zhenjiang Hu ◽  
Xuesen Zhao
Keyword(s):  
Atomic Force Microscopy ◽  
Force Control ◽  
Normal Force ◽  
Control Method ◽  
Low Cost ◽  
Three Dimensional ◽  
Control Process ◽  
Loop Control ◽  
Force Microscopy ◽  
Atomic Force

The atomic force microscopy tip-based nanomechanical machining method has already been employed to machine different kinds of nanostructures with the control of the normal force of the tip. The previous studies verified the feasibility of the nanomachining approach with the force control. However, there are still some shortcomings of small normal force, small machining scale, high cost and low machining efficiency. Therefore, in this study, a tip-based micromachining system with normal force closed-loop control is established based on the principle of atomic force microscopy. The control parameters are optimized based on an analysis of the control process to enable the production of a constant normal force during machining when using a tip tool. The maximum machining velocity that can be attained using this system while maintaining a constant normal force is obtained based on an analysis of the normal force variations during machining. By controlling nanoscale accuracy and high-precision stage, more complex microstructures, including microsquares, millimeter-scale microchannels and three-dimensional step microchannels, are successfully fabricated using the proposed force control method. Experimental results show that the tip-based normal force control method is a simple, low-cost and versatile micromachining method with the potential ability to machine more complex structures and is likely to find wider applications in the micromachining field.

FORCE CONTROL OF A REHABILITATION WALKER FOR STANDING ASSISTANCE WITH STABILITY

2009 ◽  
Vol 06 (01) ◽  
pp. 47-60 ◽  
Author(s):  
DAISUKE CHUGO ◽  
KUNIKATSU TAKASE
Keyword(s):  
Control System ◽  
Force Control ◽  
Position Control ◽  
Control Method ◽  
Daily Life ◽  
Low Cost ◽  
Assistance System ◽  
Aged People ◽  
Standing Up ◽  
Power Assistance

This paper proposes a walker system with power assistance device for standing-up motion. Our system focuses on family use for aged people who need nursing in their daily life. Our key ideas are based on two topics. The first topic is new assistance manipulator mechanism with four parallel linkages. Our proposed manipulator mechanism requires only smaller actuators and realizes rigid structure with lighter linkages compared with general manipulator. Thus, we can design our assistance system compactly with low-cost using our mechanism. The second topic is the combination of force and position control. According to the patient's posture during standing-up, our control system selects more appropriate control method from them. Furthermore, the walker coordinates its assistance position and maintains the stable posture of the patient during standing assistance. We use the reference of standing-up motion which is based on the typical standing-up motion by a nursing specialist for realizing the natural assistance. The performance of our proposed assistance system is verified by experiments using our prototype.

scholarly journals Robot arm control method using forearm EMG signals

2020 ◽  
Vol 309 ◽  
pp. 04007
Author(s):  
Minjie Chen ◽  
Honghai Liu
Keyword(s):  
Continuous Improvement ◽  
Control Method ◽  
Recognition Rate ◽  
Robotic Arm ◽  
Support Vector ◽  
Robot Arm ◽  
Svm Algorithm ◽  
Input Signals ◽  
Robot Arm Control ◽  
The Cost

With the continuous improvement of control technology and the continuous improvement of people’s living standards, the needs of disabled people for high-quality prosthetics have become increasingly strong. A control method of robotic arm based on surface electromyography signal (sEMG) of forearm is proposed. Firstly, the 16-channel EMG data of the forearm is obtained via the multi-channel EMG acquisition instrument and the electrode cuff as input signals, the features are extracted, then the gestures are classified and identified by the support-vector machine (SVM) algorithm, and the signals are finally transmitted to the robotic arm, so that people can teleoperate the robotic arm via sEMG signals in real time. Reduce the number of channels to lower the cost while ensuring a high and usable recognition rate. Experiments were performed by collecting EMG signals from the forearm surface of eight healthy volunteers. The experimental results show that the system’s overall gesture recognition accuracy rate can reach up to 90%, and the system responds fast, laying a good foundation for manipulating artificial limbs in the future.

scholarly journals Development of a Virtual Force Sensor for a Low-Cost Collaborative Robot and Applications to Safety Control

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2603 ◽  
Author(s):  
Shih-Hsiang Yen ◽  
Pei-Chong Tang ◽  
Yuan-Chiu Lin ◽  
Chyi-Yeu Lin
Keyword(s):  
Contact Force ◽  
External Force ◽  
Force Control ◽  
Low Cost ◽  
Force Sensor ◽  
Production Costs ◽  
Robot Arm ◽  
Robot Arms ◽  
Virtual Force ◽  
Collaborative Robot

To protect operators and conform to safety standards for human–machine interactions, the design of collaborative robot arms often incorporates flexible mechanisms and force sensors to detect and absorb external impact forces. However, this approach increases production costs, making the introduction of such robot arms into low-cost service applications difficult. This study proposes a low-cost, sensorless rigid robot arm design that employs a virtual force sensor and stiffness control to enable the safety collision detection and low-precision force control of robot arms. In this design, when a robot arm is subjected to an external force while in motion, the contact force observer estimates the external torques on each joint according to the motor electric current and calculation errors of the system model, which are then used to estimate the external contact force exerted on the robot arm’s end-effector. Additionally, a torque saturation limiter is added to the servo drive for each axis to enable the real-time adjustment of joint torque output according to the estimated external force, regulation of system stiffness, and achievement of impedance control that can be applied in safety measures and force control. The design this study developed is a departure from the conventional multisensor flexible mechanism approach. Moreover, it is a low-cost and sensorless design that relies on model-based control for stiffness regulation, thereby improving the safety and force control in robot arm applications.

Advance Protection for Three Phase Induction Motor using Microcontroller Atmega32

2018 ◽  
Vol 8 (1) ◽  
pp. 172
Author(s):  
Karan S Belsare ◽  
Gajanan D Patil
Keyword(s):  
Induction Motor ◽  
Low Cost ◽  
Short Circuit ◽  
Cost Factor ◽  
Protection Scheme ◽  
Three Phase ◽  
The Cost

A low cost and reliable protection scheme has been designed for a three phase induction motor against unbalance voltages, under voltage, over voltage, short circuit and overheating protection. Taking the cost factor into consideration the design has been proposed using microcontroller Atmega32, MOSFETs, relays, small CTs and PTs. However the sensitivity of the protection scheme has been not compromised. The design has been tested online in the laboratory for small motors and the same can be implemented for larger motors by replacing the i-v converters and relays of suitable ratings.

Janus – A New Approach to Air Combat Pilot Training

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Georges Bridel ◽  
Zdobyslaw Goraj ◽  
Lukasz Kiszkowiak ◽  
Jean-Georges Brévot ◽  
Jean-Pierre Devaux ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Training System ◽  
Embedded Sensors ◽  
Pilot Training ◽  
New Approach ◽  
Combat Aircraft ◽  
Air Combat ◽  
The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

scholarly journals A low-cost wireless endoscope camera: a preliminary report

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
J. M. Lazarus ◽  
M. Ncube
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Video Transmission ◽  
Low Cost ◽  
Battery Life ◽  
Resource Constrained ◽  
High Definition ◽  
Industry Standard ◽  
Constrained Environments ◽  
The Cost

Abstract Background Technology currently used for surgical endoscopy was developed and is manufactured in high-income economies. The cost of this equipment makes technology transfer to resource constrained environments difficult. We aimed to design an affordable wireless endoscope to aid visualisation during rigid endoscopy and minimally invasive surgery (MIS). The initial prototype aimed to replicate a 4-mm lens used in rigid cystoscopy. Methods Focus was placed on using open-source resources to develop the wireless endoscope to significantly lower the cost and make the device accessible for resource-constrained settings. An off the shelf miniature single-board computer module was used because of its low cost (US$10) and its ability to handle high-definition (720p) video. Open-source Linux software made monitor mode (“hotspot”) wireless video transmission possible. A 1280 × 720 pixel high-definition tube camera was used to generate the video signal. Video is transmitted to a standard laptop computer for display. Bench testing included latency of wireless digital video transmission. Comparison to industry standard wired cameras was made including weight and cost. The battery life was also assessed. Results In comparison with industry standard cystoscope lens, wired camera, video processing unit and light source, the prototype costs substantially less. (US$ 230 vs 28 000). The prototype is light weight (184 g), has no cables tethering and has acceptable battery life (of over 2 h, using a 1200 mAh battery). The camera transmits video wirelessly in near real time with only imperceptible latency of < 200 ms. Image quality is high definition at 30 frames per second. Colour rendering is good, and white balancing is possible. Limitations include the lack of a zoom. Conclusion The novel wireless endoscope camera described here offers equivalent high-definition video at a markedly reduced cost to contemporary industry wired units and could contribute to making minimally invasive surgery possible in resource-constrained environments.

scholarly journals Multi-Blockchain-Based IoT Data Processing Techniques to Ensure the Integrity of IoT Data in AIoT Edge Computing Environments

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3515
Author(s):  
Sung-Ho Sim ◽  
Yoon-Su Jeong
Keyword(s):  
Low Cost ◽  
Third Party ◽  
Monitoring And Control ◽  
Constant Size ◽  
Computing Environments ◽  
Iot Devices ◽  
Cloud Servers ◽  
The Cost ◽  
Processing Techniques ◽  
And Control

As the development of IoT technologies has progressed rapidly recently, most IoT data are focused on monitoring and control to process IoT data, but the cost of collecting and linking various IoT data increases, requiring the ability to proactively integrate and analyze collected IoT data so that cloud servers (data centers) can process smartly. In this paper, we propose a blockchain-based IoT big data integrity verification technique to ensure the safety of the Third Party Auditor (TPA), which has a role in auditing the integrity of AIoT data. The proposed technique aims to minimize IoT information loss by multiple blockchain groupings of information and signature keys from IoT devices. The proposed technique allows IoT information to be effectively guaranteed the integrity of AIoT data by linking hash values designated as arbitrary, constant-size blocks with previous blocks in hierarchical chains. The proposed technique performs synchronization using location information between the central server and IoT devices to manage the cost of the integrity of IoT information at low cost. In order to easily control a large number of locations of IoT devices, we perform cross-distributed and blockchain linkage processing under constant rules to improve the load and throughput generated by IoT devices.

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