Bhivraj Suthar - Academia.edu (original) (raw)
Papers by Bhivraj Suthar
2018 IEEE Haptics Symposium (HAPTICS)
Numerous studies have been conducted to develop a tactile device for providing convincing tactile... more Numerous studies have been conducted to develop a tactile device for providing convincing tactile feedback. However, most of the devices are limited in portability, and restricted to delivering either texture information with vibration cues or contact orientation with force feedback. To the best of our knowledge, there has been no wearable tactile display, which can display texture information together with contact orientation. In this paper, we propose a ferro-fluid based tactile display, which is lightweight and wearable and can replicate convincing contact orientation together with texture information. New design principle of introducing ferro-fluid and minimizing moving actuator components and replacing them with permanent magnet, allows the device to be compact and increases its portability. This also enables it to provide both contact orientation and texture cues. Preliminary experimental evaluation for force profile on fingernail and fingertip has been carried out. In addition, experiments for curvature discrimination and cuing simultaneous orientation and vibrational information by using an experimental prototype have also been conducted.
IEEE Access
Tremor is an involuntary action and a common problem for elderly people and other age groups to p... more Tremor is an involuntary action and a common problem for elderly people and other age groups to perform daily activities. To assist those people in conducting daily activities, suppressing hand tremors is necessary. A flexure mechanism system can be placed as a tabletop device on which the elbow can be positioned to compensate for the tremor. Using this methodology, in this paper, flexure-based mechanisms for the hand tremor are proposed to help people perform eating activities easily. Flexure mechanisms with three different connection arrangements are designed, modeled (as pseudo-rigid bodies), analyzed, and developed. Finite element analysis is conducted to verify the results of the pseudo-rigid models for passive conditions. An experimental setup is accessed for both passive and active schemes, consisting of two link mechanisms, having a precise one-DOF tremor generated at the end-effector of the experimental setup arm. Gyroscope sensors are used to monitor the tremor present. A series of experiments are conducted for two cases: when flexure mechanisms are connected passively and when flexure mechanism is connected actively. It was found that the flexure mechanism can compensate for the tremor in passive and active mode by approximately 75% to 90%, respectively. INDEX TERMS Curved flexure, hand tremor, pseudo-rigid model, passive and active tremor compensation.
Journal of Mechanisms and Robotics, 2021
The conventional scissor mechanism is used in modern engineering and robotic applications due to ... more The conventional scissor mechanism is used in modern engineering and robotic applications due to its metamorphic ability. The folding configuration provides space-saving and unfolding provides longer linear expansion capability. However, a conventional scissor suffers unexpected and uncontrolled large bending deformation due to low bending stiffness while unfolding configuration, which may damage its structure. It also has a sudden bending singularity during unfolding, which may also damage the actuator. These limitations impose a significant constraint on real-life applications such as foldable robot arms, space robot arms, and reconfigurable robots. In this paper, we proposed a multi-strands parallel twisted-scissor mechanism (PTSM) to enhance its usability. The PTSM is inspired by a rope structure and designed by introducing a metamorphic segment (MS) using the S-shaped linkage design approach to improve its bending stiffness without affecting conventional scissors’ fundamentals....
2017 International Conference on Innovations in Control, Communication and Information Systems (ICICCI), 2017
Filtering is most important and critical task to immaculate information like edge detection, obje... more Filtering is most important and critical task to immaculate information like edge detection, object identification, brightness, contrast etc. from the noisy image. Various types of noises are due to faulty instrument, temperate rise of camera and some time added intentionally to preserve other useful information of the image and also depends on its transmission over various media like space to earth through vacuum media and Sea to earth station through water media etc. In this paper we presented essential used noises and filtering techniques and simulated in matlab. We discussed the noise effects and its corresponding filters. We also simulated and discussed best suitable filter to various type of noise and its results on standard image in matlab.
Robotica, 2021
The design and development of an upper limb exoskeleton are being discussed for the tele-operatio... more The design and development of an upper limb exoskeleton are being discussed for the tele-operation in order to control the KUKA KR5 industrial robot. When sufficient resolution is not provided by the visual feedback, feedback of haptic provides a qualitative understanding of changes in the remote conditions. This also provides tactile feedback from the virtual and real environment. Peg in a hole operation using exoskeleton works as the master for tele-operation in order to control the robot using immersive environment as visual feedback for the operator. The application of this work can be implemented as a nuclear power generation plant.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
Flexure mechanism has micro and macro application over conventional mechanism. There are no frict... more Flexure mechanism has micro and macro application over conventional mechanism. There are no frictional losses, compactness, no lubrication and no maintenance required. With advances in simulation technology designing of flexure mechanism is quite easy and can be tested in simulation before it can be deployed in the system. Although the force analysis of flexure mechanism can be easily studied using the simulation environment, its realistic performance is very much required before it can be deployed to a real system. This paper presents an experimental setup to conduct the experiment on the flexure mechanism. A test-bed is built consisting of an actuator, a 6-axes load sensor, an accelerometer and a customized closure. A flexure mechanism is designed to suppress the vibration developed at a joint of a robot due to the presence of an actuator. The designed system is simulated in ANSYS environment to study the flexibility of the system to the applied load. A flexure mechanism is fabricated using 3D printer technology. A series of experiment was conducted to verify the simulation results and found it suitable for its deployment.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
This paper deals with the bird's nest cleaning equipment, particularly a new type of bird'... more This paper deals with the bird's nest cleaning equipment, particularly a new type of bird's nest-removing Hawk claw gripper for power transmission towers. Bird's nests are often built on the transmission and distribution network towers. The wooden branches, grass stems, wires and other materials that birds use to make the nest can easily cause the short connection of the power line, causing fire or even burning out the equipment. Causing a power line failure makes a great impact on the economy and human lives. This paper proposed a Hawk-inspired bird's nest cleaning gripper design for a drone arm with three fingers with a long curved talon. The gripper finger talon can penetrate deeper into the nest structure to grip firmly and a drone moves it. The hawk gripper can be easily connected to a foldable drone arm and operated remotely on the electrical tower. We developed a prototype of a hawk gripper and demonstrated its feasibility.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
Humans hand has a complex functionality to achieve stable and reliable gripping of irregular-shap... more Humans hand has a complex functionality to achieve stable and reliable gripping of irregular-shaped objects. This paper aims to design a three-finger anthropomorphic gripper and endow the designed hand with natural grasping functions. We introduce a passively adjustable flexion finger mechanism that can change a flexion finger angle according to the irregular-shaped objects. Each finger of the gripper has a torsional spring and has placed co-axially, connected in series on an equilateral triangular palm. The required stiffness of the flexion angle and object safety condition is analyzed. The variation of the flexion joint stiffness for the minimum to maximum flexion angle is evaluated. Practical experiments using a wide range of obj ects under different grasping scenarios are performed to demonstrate the grasping capability of the integrated gripper.
2016 International Conference on Robotics and Automation for Humanitarian Applications (RAHA), 2016
In this paper design of Exoskeleton robot depending on human anthropometry has been discussed. Sh... more In this paper design of Exoskeleton robot depending on human anthropometry has been discussed. Shoulder joint contributes most of the work space, kinematic model of shoulder joint has been discussed. Further the challenge lies with mapping this 7 DOF arm exoskeleton to a 6 DOF industrial robot. This has been addressed using the virtual KUKA model. Validation is done and same has been shown using C# and Autodesk plugin module.
2016 International Conference on Robotics and Automation for Humanitarian Applications (RAHA), 2016
Robot hands with lower degree of freedom are used to reproduce the gesture of our hand, there are... more Robot hands with lower degree of freedom are used to reproduce the gesture of our hand, there are many gestures of our hand which cannot be reproduced in these hands. In this paper, we propose a design of anthropomorphic robot hand using twenty servo motor for twenty degree of freedoms which we can reproduce the exact and every gesture of our hand so that it is suitable for dexterous task like surgery. The accuracy of the proposed design to reproduce gestures and motion of our hand by simulating in Leap Motion Diagnostic Visualizer using Leap Motion Controller as a sensor are measured in this paper. The angle measurement method between fingers and bones of the same finger in Leap Motion Controller is also presented. Accuracy test and control system is also described.
2021 18th International Conference on Ubiquitous Robots (UR), 2021
This paper presents a novel design of a foldable scissor structure introducing twisting of scisso... more This paper presents a novel design of a foldable scissor structure introducing twisting of scissor structure on each other to enhance bending strength of traditional scissor structure. The twisted-scissor structure (TSS) was built on designing S-shape links using a linkage design approach. TSS consists of a series of S-shape metamorphic segments (MSs). Each segment is composed of S-shape links and a revolute joint node as a key segment in a foldable twisted-scissor mechanism for mobility bifurcation, which changes its shape from compact to fully extended. A series of simulations in the vertical and horizontal working situation is performed. The simulation results of TSS with the parallel-scissor structure (PSS) were analyzed and compared. TSS shows double bending strength than the PSS. At last, based on design and simulation results, a prototype of TSS was developed and successfully demonstrated its feasibility.
2021 18th International Conference on Ubiquitous Robots (UR), 2021
Flexure mechanism in a robotic system can improve the accuracy to perform work and reduce the dam... more Flexure mechanism in a robotic system can improve the accuracy to perform work and reduce the damage that may have encountered due to the sudden motion. In this paper a flexure mechanism is proposed for the end-effector of a foldable robot arm for a drone, designed and operated for a solar panel cleaning task. The proposed flexure mechanism provides decoupled motions along the two rotational axes (θX and θY) and high stiffness about one rotational axis (θZ). The stiffness axis of the flexure mechanism is aligned about the cleaning motor torque axis such that the maximum torque can be transmitted to perform the task and undesirable motion about the other axes can be minimized. The simulation was conducted to determine the stiffness of the different axis using FE package. The performance of the foldable robot arm for a drone operated on a solar panel cleaning task has been tested to demonstrate the vibration suppression by the flexure mechanism.
IEEE Robotics and Automation Letters, 2021
This paper presents a feasible analysis of a foldable robot arm for drones (FRAD) for payload lif... more This paper presents a feasible analysis of a foldable robot arm for drones (FRAD) for payload lifting without drone landing. The arm design is aimed to be light, foldable and energy-efficient. FRAD is designed with a scissor mechanism in a parallel arrangement actuated by a twisted string actuator (TSA) with a guide. The robot arm can fold, unfold, and easily deploy on drones by having benefit from inherent TSA advantages. We propose a linkage design approach to provide a solution to mechanical singularity and to improve a space-saving capability. The nonlinear pulling force of twisted strings’ transmission ratio (decreasing with twisting) closely matched the typical force profile requirement for folding the arm. This fact was used in the foldable robot arm for its optimal actuation design. The required string torque and twist angle were calculated to generate a pulling force to fold the arm with a 0.3kg payload from the unfolded to the fully folded situation. Preliminary experimental trials demonstrated that the proposed FRAD could generate the required lifting force and fold the arm without a high torque motor.
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018
Twisted string actuators (TSAs) are gaining popularity in modern engineering and robotic applicat... more Twisted string actuators (TSAs) are gaining popularity in modern engineering and robotic applications. However, in conventional actuators of this type, the twisted part of the string should not be in contact with any surfaces or objects because this may interfere with the propagation of twisting. This imposes significant constraint on potential applications of TSAs. In this paper, we investigated the feasibility of using TSAs inside conduit and demonstrated that the twists of the string can be fully propagated through the sheath and that consistent periodic behavior of the twisted string can be achieved. In addition, we investigated input-output position and force characteristics of TSAs for various deflection angles of the conduit, effect of lubrication on transmission efficiency, and compared it with conventional cable sliding transmission. We found that TSA has higher transmission efficiency than sliding due to decreased friction between the string and conduit, which is further improved by lubrication. We have managed to achieve 85 % of force transmission efficiency for the case of lubricated twisting, as opposed to the 71.74% for lubricated sliding.
2021 IEEE 17th International Conference on Automation Science and Engineering (CASE), 2021
A new type of wearable robot is introduced to provide supplementary arms for assisting the worker... more A new type of wearable robot is introduced to provide supplementary arms for assisting the worker's tasks. The supplementary arm is metamorphic called Foldable Robotic Arms for Collaboration (FRAC) to extend the operational degrees-of-freedom. FRAC provides additional two arms for a worker to augment the tasks with the environment where the additional arms are necessary. Initially, the FRAC is folded for saving the workspace to allow more space for human arms to interact with the environment. It is unfolded when the worker needs extra arms to hold the object. The strategy for assisting the worker is described, and kinematics and simulation analysis of the folding and unfolding are performed. FRAC is developed for its feasible functionality by performing the conceptual drilling and screwing operation for construction work with the FRAC.
2017 IEEE International Conference on Robotics and Automation (ICRA), 2017
The twisted string actuator is an actuator that is gaining popularity in various engineering and ... more The twisted string actuator is an actuator that is gaining popularity in various engineering and robotics and applications. However, the fundamental limitation of actuators of this type is the uni-directional action, meaning that the actuator can contract but requires external power to return to its initial state. This paper proposes 2 novel passive extension mechanisms based on buckling effect to solve the uni-directional issue of the twisted string actuator. The proposed mechanisms are mechanically simple and compact and provide a nearly-constant extension force throughout the operation range. The constant force can fully extend the twisted string actuator with minimal loss of force during contraction. The designed mechanisms are evaluated in a series of practical tests, and their performances are compared and discussed.
Applied Sciences, 2020
Health-related limitations prohibit a human from working in hazardous environments, due to which ... more Health-related limitations prohibit a human from working in hazardous environments, due to which cognitive robots are needed to work there. A robot cannot learn the spatial semantics of the environment or object, which hinders the robot from interacting with the working environment. To overcome this problem, in this work, an agent is computationally devised that mimics the grid and place neuron functionality to learn cognitive maps from the input spatial data of an environment or an object. A novel quadrant-based approach is proposed to model the behavior of the grid neuron, which, like the real grid neuron, is capable of generating periodic hexagonal grid-like output patterns from the input body movement. Furthermore, a cognitive map formation and their learning mechanism are proposed using the place–grid neuron interaction system, which is meant for making predictions of environmental sensations from the body movement. A place sequence learning system is also introduced, which is ...
IEEE Robotics and Automation Letters, 2019
In this paper is proposed a variable-radius pulley (VRP) to linearize input-output behavior of tw... more In this paper is proposed a variable-radius pulley (VRP) to linearize input-output behavior of twisted string actuators (TSA). With the help of a VRP, it is possible to make the inherently nonlinear transmission ratio of twisted string constant. This enables design of bidirectional transmission systems driven by a single motor, much like is done in conventional belt transmissions. Herein, we analyze the limitations on employing constant-radius pulleys in bidirectional twisted string transmission systems and propose a VRP design methodology based on TSA kinematics. We manufactured the pulley and evaluated its performance experimentally in a series of unidirectional and bidirectional actuations. The experiments demonstrated that the resultant transmission ratio from motor to load remained nearly constant as expected from the simulation results. Different statistical measures for error between the experimental and simulated results were also calculated.
The Proceedings of the Asian Conference on Multibody Dynamics, 2016
2018 IEEE Haptics Symposium (HAPTICS)
Numerous studies have been conducted to develop a tactile device for providing convincing tactile... more Numerous studies have been conducted to develop a tactile device for providing convincing tactile feedback. However, most of the devices are limited in portability, and restricted to delivering either texture information with vibration cues or contact orientation with force feedback. To the best of our knowledge, there has been no wearable tactile display, which can display texture information together with contact orientation. In this paper, we propose a ferro-fluid based tactile display, which is lightweight and wearable and can replicate convincing contact orientation together with texture information. New design principle of introducing ferro-fluid and minimizing moving actuator components and replacing them with permanent magnet, allows the device to be compact and increases its portability. This also enables it to provide both contact orientation and texture cues. Preliminary experimental evaluation for force profile on fingernail and fingertip has been carried out. In addition, experiments for curvature discrimination and cuing simultaneous orientation and vibrational information by using an experimental prototype have also been conducted.
IEEE Access
Tremor is an involuntary action and a common problem for elderly people and other age groups to p... more Tremor is an involuntary action and a common problem for elderly people and other age groups to perform daily activities. To assist those people in conducting daily activities, suppressing hand tremors is necessary. A flexure mechanism system can be placed as a tabletop device on which the elbow can be positioned to compensate for the tremor. Using this methodology, in this paper, flexure-based mechanisms for the hand tremor are proposed to help people perform eating activities easily. Flexure mechanisms with three different connection arrangements are designed, modeled (as pseudo-rigid bodies), analyzed, and developed. Finite element analysis is conducted to verify the results of the pseudo-rigid models for passive conditions. An experimental setup is accessed for both passive and active schemes, consisting of two link mechanisms, having a precise one-DOF tremor generated at the end-effector of the experimental setup arm. Gyroscope sensors are used to monitor the tremor present. A series of experiments are conducted for two cases: when flexure mechanisms are connected passively and when flexure mechanism is connected actively. It was found that the flexure mechanism can compensate for the tremor in passive and active mode by approximately 75% to 90%, respectively. INDEX TERMS Curved flexure, hand tremor, pseudo-rigid model, passive and active tremor compensation.
Journal of Mechanisms and Robotics, 2021
The conventional scissor mechanism is used in modern engineering and robotic applications due to ... more The conventional scissor mechanism is used in modern engineering and robotic applications due to its metamorphic ability. The folding configuration provides space-saving and unfolding provides longer linear expansion capability. However, a conventional scissor suffers unexpected and uncontrolled large bending deformation due to low bending stiffness while unfolding configuration, which may damage its structure. It also has a sudden bending singularity during unfolding, which may also damage the actuator. These limitations impose a significant constraint on real-life applications such as foldable robot arms, space robot arms, and reconfigurable robots. In this paper, we proposed a multi-strands parallel twisted-scissor mechanism (PTSM) to enhance its usability. The PTSM is inspired by a rope structure and designed by introducing a metamorphic segment (MS) using the S-shaped linkage design approach to improve its bending stiffness without affecting conventional scissors’ fundamentals....
2017 International Conference on Innovations in Control, Communication and Information Systems (ICICCI), 2017
Filtering is most important and critical task to immaculate information like edge detection, obje... more Filtering is most important and critical task to immaculate information like edge detection, object identification, brightness, contrast etc. from the noisy image. Various types of noises are due to faulty instrument, temperate rise of camera and some time added intentionally to preserve other useful information of the image and also depends on its transmission over various media like space to earth through vacuum media and Sea to earth station through water media etc. In this paper we presented essential used noises and filtering techniques and simulated in matlab. We discussed the noise effects and its corresponding filters. We also simulated and discussed best suitable filter to various type of noise and its results on standard image in matlab.
Robotica, 2021
The design and development of an upper limb exoskeleton are being discussed for the tele-operatio... more The design and development of an upper limb exoskeleton are being discussed for the tele-operation in order to control the KUKA KR5 industrial robot. When sufficient resolution is not provided by the visual feedback, feedback of haptic provides a qualitative understanding of changes in the remote conditions. This also provides tactile feedback from the virtual and real environment. Peg in a hole operation using exoskeleton works as the master for tele-operation in order to control the robot using immersive environment as visual feedback for the operator. The application of this work can be implemented as a nuclear power generation plant.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
Flexure mechanism has micro and macro application over conventional mechanism. There are no frict... more Flexure mechanism has micro and macro application over conventional mechanism. There are no frictional losses, compactness, no lubrication and no maintenance required. With advances in simulation technology designing of flexure mechanism is quite easy and can be tested in simulation before it can be deployed in the system. Although the force analysis of flexure mechanism can be easily studied using the simulation environment, its realistic performance is very much required before it can be deployed to a real system. This paper presents an experimental setup to conduct the experiment on the flexure mechanism. A test-bed is built consisting of an actuator, a 6-axes load sensor, an accelerometer and a customized closure. A flexure mechanism is designed to suppress the vibration developed at a joint of a robot due to the presence of an actuator. The designed system is simulated in ANSYS environment to study the flexibility of the system to the applied load. A flexure mechanism is fabricated using 3D printer technology. A series of experiment was conducted to verify the simulation results and found it suitable for its deployment.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
This paper deals with the bird's nest cleaning equipment, particularly a new type of bird'... more This paper deals with the bird's nest cleaning equipment, particularly a new type of bird's nest-removing Hawk claw gripper for power transmission towers. Bird's nests are often built on the transmission and distribution network towers. The wooden branches, grass stems, wires and other materials that birds use to make the nest can easily cause the short connection of the power line, causing fire or even burning out the equipment. Causing a power line failure makes a great impact on the economy and human lives. This paper proposed a Hawk-inspired bird's nest cleaning gripper design for a drone arm with three fingers with a long curved talon. The gripper finger talon can penetrate deeper into the nest structure to grip firmly and a drone moves it. The hawk gripper can be easily connected to a foldable drone arm and operated remotely on the electrical tower. We developed a prototype of a hawk gripper and demonstrated its feasibility.
2021 21st International Conference on Control, Automation and Systems (ICCAS), 2021
Humans hand has a complex functionality to achieve stable and reliable gripping of irregular-shap... more Humans hand has a complex functionality to achieve stable and reliable gripping of irregular-shaped objects. This paper aims to design a three-finger anthropomorphic gripper and endow the designed hand with natural grasping functions. We introduce a passively adjustable flexion finger mechanism that can change a flexion finger angle according to the irregular-shaped objects. Each finger of the gripper has a torsional spring and has placed co-axially, connected in series on an equilateral triangular palm. The required stiffness of the flexion angle and object safety condition is analyzed. The variation of the flexion joint stiffness for the minimum to maximum flexion angle is evaluated. Practical experiments using a wide range of obj ects under different grasping scenarios are performed to demonstrate the grasping capability of the integrated gripper.
2016 International Conference on Robotics and Automation for Humanitarian Applications (RAHA), 2016
In this paper design of Exoskeleton robot depending on human anthropometry has been discussed. Sh... more In this paper design of Exoskeleton robot depending on human anthropometry has been discussed. Shoulder joint contributes most of the work space, kinematic model of shoulder joint has been discussed. Further the challenge lies with mapping this 7 DOF arm exoskeleton to a 6 DOF industrial robot. This has been addressed using the virtual KUKA model. Validation is done and same has been shown using C# and Autodesk plugin module.
2016 International Conference on Robotics and Automation for Humanitarian Applications (RAHA), 2016
Robot hands with lower degree of freedom are used to reproduce the gesture of our hand, there are... more Robot hands with lower degree of freedom are used to reproduce the gesture of our hand, there are many gestures of our hand which cannot be reproduced in these hands. In this paper, we propose a design of anthropomorphic robot hand using twenty servo motor for twenty degree of freedoms which we can reproduce the exact and every gesture of our hand so that it is suitable for dexterous task like surgery. The accuracy of the proposed design to reproduce gestures and motion of our hand by simulating in Leap Motion Diagnostic Visualizer using Leap Motion Controller as a sensor are measured in this paper. The angle measurement method between fingers and bones of the same finger in Leap Motion Controller is also presented. Accuracy test and control system is also described.
2021 18th International Conference on Ubiquitous Robots (UR), 2021
This paper presents a novel design of a foldable scissor structure introducing twisting of scisso... more This paper presents a novel design of a foldable scissor structure introducing twisting of scissor structure on each other to enhance bending strength of traditional scissor structure. The twisted-scissor structure (TSS) was built on designing S-shape links using a linkage design approach. TSS consists of a series of S-shape metamorphic segments (MSs). Each segment is composed of S-shape links and a revolute joint node as a key segment in a foldable twisted-scissor mechanism for mobility bifurcation, which changes its shape from compact to fully extended. A series of simulations in the vertical and horizontal working situation is performed. The simulation results of TSS with the parallel-scissor structure (PSS) were analyzed and compared. TSS shows double bending strength than the PSS. At last, based on design and simulation results, a prototype of TSS was developed and successfully demonstrated its feasibility.
2021 18th International Conference on Ubiquitous Robots (UR), 2021
Flexure mechanism in a robotic system can improve the accuracy to perform work and reduce the dam... more Flexure mechanism in a robotic system can improve the accuracy to perform work and reduce the damage that may have encountered due to the sudden motion. In this paper a flexure mechanism is proposed for the end-effector of a foldable robot arm for a drone, designed and operated for a solar panel cleaning task. The proposed flexure mechanism provides decoupled motions along the two rotational axes (θX and θY) and high stiffness about one rotational axis (θZ). The stiffness axis of the flexure mechanism is aligned about the cleaning motor torque axis such that the maximum torque can be transmitted to perform the task and undesirable motion about the other axes can be minimized. The simulation was conducted to determine the stiffness of the different axis using FE package. The performance of the foldable robot arm for a drone operated on a solar panel cleaning task has been tested to demonstrate the vibration suppression by the flexure mechanism.
IEEE Robotics and Automation Letters, 2021
This paper presents a feasible analysis of a foldable robot arm for drones (FRAD) for payload lif... more This paper presents a feasible analysis of a foldable robot arm for drones (FRAD) for payload lifting without drone landing. The arm design is aimed to be light, foldable and energy-efficient. FRAD is designed with a scissor mechanism in a parallel arrangement actuated by a twisted string actuator (TSA) with a guide. The robot arm can fold, unfold, and easily deploy on drones by having benefit from inherent TSA advantages. We propose a linkage design approach to provide a solution to mechanical singularity and to improve a space-saving capability. The nonlinear pulling force of twisted strings’ transmission ratio (decreasing with twisting) closely matched the typical force profile requirement for folding the arm. This fact was used in the foldable robot arm for its optimal actuation design. The required string torque and twist angle were calculated to generate a pulling force to fold the arm with a 0.3kg payload from the unfolded to the fully folded situation. Preliminary experimental trials demonstrated that the proposed FRAD could generate the required lifting force and fold the arm without a high torque motor.
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018
Twisted string actuators (TSAs) are gaining popularity in modern engineering and robotic applicat... more Twisted string actuators (TSAs) are gaining popularity in modern engineering and robotic applications. However, in conventional actuators of this type, the twisted part of the string should not be in contact with any surfaces or objects because this may interfere with the propagation of twisting. This imposes significant constraint on potential applications of TSAs. In this paper, we investigated the feasibility of using TSAs inside conduit and demonstrated that the twists of the string can be fully propagated through the sheath and that consistent periodic behavior of the twisted string can be achieved. In addition, we investigated input-output position and force characteristics of TSAs for various deflection angles of the conduit, effect of lubrication on transmission efficiency, and compared it with conventional cable sliding transmission. We found that TSA has higher transmission efficiency than sliding due to decreased friction between the string and conduit, which is further improved by lubrication. We have managed to achieve 85 % of force transmission efficiency for the case of lubricated twisting, as opposed to the 71.74% for lubricated sliding.
2021 IEEE 17th International Conference on Automation Science and Engineering (CASE), 2021
A new type of wearable robot is introduced to provide supplementary arms for assisting the worker... more A new type of wearable robot is introduced to provide supplementary arms for assisting the worker's tasks. The supplementary arm is metamorphic called Foldable Robotic Arms for Collaboration (FRAC) to extend the operational degrees-of-freedom. FRAC provides additional two arms for a worker to augment the tasks with the environment where the additional arms are necessary. Initially, the FRAC is folded for saving the workspace to allow more space for human arms to interact with the environment. It is unfolded when the worker needs extra arms to hold the object. The strategy for assisting the worker is described, and kinematics and simulation analysis of the folding and unfolding are performed. FRAC is developed for its feasible functionality by performing the conceptual drilling and screwing operation for construction work with the FRAC.
2017 IEEE International Conference on Robotics and Automation (ICRA), 2017
The twisted string actuator is an actuator that is gaining popularity in various engineering and ... more The twisted string actuator is an actuator that is gaining popularity in various engineering and robotics and applications. However, the fundamental limitation of actuators of this type is the uni-directional action, meaning that the actuator can contract but requires external power to return to its initial state. This paper proposes 2 novel passive extension mechanisms based on buckling effect to solve the uni-directional issue of the twisted string actuator. The proposed mechanisms are mechanically simple and compact and provide a nearly-constant extension force throughout the operation range. The constant force can fully extend the twisted string actuator with minimal loss of force during contraction. The designed mechanisms are evaluated in a series of practical tests, and their performances are compared and discussed.
Applied Sciences, 2020
Health-related limitations prohibit a human from working in hazardous environments, due to which ... more Health-related limitations prohibit a human from working in hazardous environments, due to which cognitive robots are needed to work there. A robot cannot learn the spatial semantics of the environment or object, which hinders the robot from interacting with the working environment. To overcome this problem, in this work, an agent is computationally devised that mimics the grid and place neuron functionality to learn cognitive maps from the input spatial data of an environment or an object. A novel quadrant-based approach is proposed to model the behavior of the grid neuron, which, like the real grid neuron, is capable of generating periodic hexagonal grid-like output patterns from the input body movement. Furthermore, a cognitive map formation and their learning mechanism are proposed using the place–grid neuron interaction system, which is meant for making predictions of environmental sensations from the body movement. A place sequence learning system is also introduced, which is ...
IEEE Robotics and Automation Letters, 2019
In this paper is proposed a variable-radius pulley (VRP) to linearize input-output behavior of tw... more In this paper is proposed a variable-radius pulley (VRP) to linearize input-output behavior of twisted string actuators (TSA). With the help of a VRP, it is possible to make the inherently nonlinear transmission ratio of twisted string constant. This enables design of bidirectional transmission systems driven by a single motor, much like is done in conventional belt transmissions. Herein, we analyze the limitations on employing constant-radius pulleys in bidirectional twisted string transmission systems and propose a VRP design methodology based on TSA kinematics. We manufactured the pulley and evaluated its performance experimentally in a series of unidirectional and bidirectional actuations. The experiments demonstrated that the resultant transmission ratio from motor to load remained nearly constant as expected from the simulation results. Different statistical measures for error between the experimental and simulated results were also calculated.
The Proceedings of the Asian Conference on Multibody Dynamics, 2016