A Method of Swing Leg Control for a Minimally Actuated Medical Exoskeleton for Individuals With Paralysis

2013 ◽  
Author(s):  
Jason I. Reid ◽  
Michael McKinley ◽  
Wayne Tung ◽  
Minerva Pillai ◽  
H. Kazerooni
Keyword(s):  
Energy Efficient ◽  
Degrees Of Freedom ◽  
Legged Locomotion ◽  
Swing Phase ◽  
Current Medical ◽  
Robotic Systems ◽  
State Dependent ◽  
Early Results ◽  
Natural Energy ◽  
Flexion And Extension

This paper discusses the control of a medical exoskeleton swing leg that has a “passive” (unactuated) knee. Previous work in legged locomotion has demonstrated the feasibility of achieving natural, energy efficient walking with minimally actuated robotic systems. This work will present early results for a medical exoskeleton that only has actuation that powers the flexion and extension of the biological hip. In this work, a hybrid model of the state dependent kinematics and dynamics of the swing leg will be developed and parameterized to yield swing hip dynamics as a function of desired knee flexion dynamics. This model is used to design swing hip motions that control the flexion behavior of the passive swing knee in a human-like manner. This concept was tested by a paraplegic user wearing a new minimally actuated exoskeleton. The presented results show that a human-like swing phase can be achieved with an exoskeleton that has fewer actuated degrees of freedom than current medical exoskeletons.

scholarly journals Development of Hexapod Robot with Computer Vision

2021 ◽  
Vol 9 (8) ◽  
pp. 1796-1805
Author(s):  
Abhishek C
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Digital Image Processing ◽  
Digital Image ◽  
Degrees Of Freedom ◽  
Legged Locomotion ◽  
Robotic Systems ◽  
Raspberry Pi ◽  
Hexapod Robot ◽  
Irregular Surfaces

Abstract: Nowadays many robotic systems are developed with lot of innovation, seeking to get flexibility and efficiency of biological systems. Hexapod Robot is the best example for such robots, it is a six-legged robot whose walking movements try to imitate the movements of the insects, it has two sets of three legs alternatively which is used to walk, this will provide stability, flexibility and mobility to travel on irregular surfaces. With these attributes the hexapod robots can be used to explore irregular surfaces, inhospitable places, or places which are difficult for humans to access. This paper involves the development of hexapod robot with digital image processing implemented on Raspberry Pi, to study in the areas of robotic systems with legged locomotion and robotic vision. This paper is an integration of a robotic system and an embedded system of digital image processing, programmed in high level language using Python. It is equipped with a camera to capture real time video and uses a distance sensor that allow the robot to detect obstacles. The Robot is Self-Stabilizing and can detect corners. The robot has 3 degrees of freedom in each six legs thus making a 18 DOF robotic movement. The use of multiple degrees of freedom at the joints of the legs allows the legged robots to change their movement direction without slippage. Additionally, it is possible to change the height from the ground, introducing a damping and a decoupling between the terrain irregularities and the body of the robot servo motors. Keywords: Hexapod, Raspberry Pi, Computer vision, Object detection, Yolo, Servo Motor, OpevCV.

scholarly journals Getting grip in changing environments: the effect of friction anisotropy inversion on robot locomotion

2021 ◽  
Vol 127 (5) ◽  
Author(s):  
Halvor T. Tramsen ◽  
Lars Heepe ◽  
Jettanan Homchanthanakul ◽  
Florentin Wörgötter ◽  
Stanislav N. Gorb ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Legged Locomotion ◽  
Hexapod Robot ◽  
Friction Anisotropy ◽  
Anisotropic Friction ◽  
Walking Behavior ◽  
Robot Locomotion ◽  
Computational Morphology ◽  
Anisotropic Structures ◽  
Walking Environment

AbstractLegged locomotion of robots can be greatly improved by bioinspired tribological structures and by applying the principles of computational morphology to achieve fast and energy-efficient walking. In a previous research, we mounted shark skin on the belly of a hexapod robot to show that the passive anisotropic friction properties of this structure enhance locomotion efficiency, resulting in a stronger grip on varying walking surfaces. This study builds upon these results by using a previously investigated sawtooth structure as a model surface on a legged robot to systematically examine the influences of different material and surface properties on the resulting friction coefficients and the walking behavior of the robot. By employing different surfaces and by varying the stiffness and orientation of the anisotropic structures, we conclude that with having prior knowledge about the walking environment in combination with the tribological properties of these structures, we can greatly improve the robot’s locomotion efficiency.

Kinematic Analysis and Optimization of a Novel Robot for Surgical Tool Manipulation

2008 ◽  
Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Robotic Systems ◽  
Small Space ◽  
Surgical Robots ◽  
Tool Positioning ◽  
Rotation Axes ◽  
Surgical Tool ◽  
Linear Nature

The size and limited dexterity of current surgical robotic systems are factors which limit their usefulness. To improve the level of assimilation of surgical robots in minimally invasive surgery (MIS), a compact, lightweight surgical robotic positioning mechanism with four degrees of freedom (DOF) (three rotational DOF and one translation DOF) is proposed in this paper. This spatial mechanism based on a bevel-gear wrist is remotely driven with three rotation axes intersecting at a remote rotation center (the MIS entry port). Forward and inverse kinematics are derived, and these are used for optimizing the mechanism structure given workspace requirements. By evaluating different spherical geared configurations with various link angles and pitch angles, an optimal design is achieved which performs surgical tool positioning throughout the desired kinematic workspace while occupying a small space bounded by a hemisphere of radius 13.7 cm. This optimized workspace conservatively accounts for collision avoidance between patient and robot or internally between the robot links. This resultant mechanism is highly compact and yet has the dexterity to cover the extended workspace typically required in telesurgery. It can also be used for tool tracking and skills assessment. Due to the linear nature of the gearing relationships, it may also be well suited for implementing force feedback for telesurgery.

Controlling Modular Reconfigurable Robots With Handheld Smart Devices

2011 ◽  
Author(s):  
David Ko ◽  
Nalaka Kahawatte ◽  
Harry H. Cheng
Keyword(s):  
Graphical User Interface ◽  
Degrees Of Freedom ◽  
Robotic Systems ◽  
Effective Control ◽  
Smart Devices ◽  
Modular Robots ◽  
Reconfigurable Robots ◽  
Processing Power ◽  
Static Data ◽  
Remote Controller

Highly reconfigurable modular robots face unique teleoperation challenges due to their geometry, configurability, high number of degrees of freedom and complexity. Current methodology for controlling reconfigurable modular robots typically use gait tables to control the modules. Gait tables are static data structures and do not readily support realtime teleoperation. Teleoperation techniques for traditional wheeled, flying, or submerged robots typically use a set of joysticks to control the robots. However, these traditional methods of robot teleoperation are not suitable for reconfigurable modular robotic systems which may have dozens of controllable degrees of freedom. This research shows that modern cell phones serve as highly effective control platforms for modular robots because of their programmability, flexibility, wireless communication capabilities, and increased processing power. As a result of this research, a versatile Graphical User Interface, a set of libraries and tools have been developed which even a novice robotics enthusiast can use to easily program their mobile phones to control their hobby project. These libraries will be beneficial in any situation where it is effective for the operator to use an off-the-shelf, relatively inexpensive, hand-held mobile phone as a remote controller rather than a considerably heavy and bulky remote controllers which are popular today. Several usage examples and experiments are presented which demonstrate the controller’s ability to effectively control a modular robot to perform a series of complex gaits and poses, as well as navigating a module through an obstacle course.

Mechanical Manipulator for Intuitive Control of Endoscopic Instruments With Seven Degrees of Freedom

2004 ◽  
Author(s):  
J. E. N. Jaspers ◽  
M. Shehata ◽  
F. Wijkhuizen ◽  
J. L. Herder ◽  
C. A. Grimbergen
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Robotic Systems ◽  
Complex Tasks ◽  
Steel Wires

Performing complex tasks in Minimally Invasive Surgery (MIS) is demanding due to a disturbed hand-eye co-ordination, the use of non-ergonomic instruments with limited degrees of freedom (DOFs) and a lack of force feedback. Robotic telemanipulatory systems enhance surgical dexterity by providing up to 7 DOFs. They allow the surgeon to operate in an ergonomically favorable position with more intuitive manipulation of the instruments. Commercially available robotic systems, however, are very bulky, expensive and do not provide any force feedback. The aim of our study was to develop a simple mechanical manipulator for MIS. When manipulating the handle of the device, the surgeon’s wrist and grasping movements are directly transmitted to the deflectable instrument tip in 7 DOFs. The manipulator consists of a parallelogram mechanism with steel wires. First phantom experience indicated that the system functions properly. The MIM provides some force feedback improving safety. A set of MIMs seems to be an economical and compact alternative for robotic systems.

scholarly journals Recent Design Optimization Methods for Energy-Efficient Electric Motors and Derived Requirements for a New Improved Method—Part 1

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1400
Author(s):  
Johannes Schmelcher ◽  
Max Kleine Büning ◽  
Kai Kreisköther ◽  
Dieter Gerling ◽  
Achim Kampker
Keyword(s):  
Rare Earth ◽  
Design Optimization ◽  
Energy Efficient ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Optimization Problems ◽  
Computing Time ◽  
Optimization Methods ◽  
Electric Motors ◽  
Electric Cars

Energy-efficient electric motors are gathering an increased attention since they are used in electric cars or to reduce operational costs, for instance. Due to their high efficiency, permanent-magnet synchronous motors are used progressively more. However, the need to use rare-earth magnets for such high-efficiency motors is problematic not only in regard to the cost but also in socio-political and environmental aspects. Therefore, an increasing effort has to be put in finding the best design possible. The goals to achieve are, among others, to reduce the amount of rare-earth magnet material but also to increase the efficiency. In the first part of this multipart paper, characteristics of optimization problems in engineering and general methods to solve them are presented. In part two, different approaches to the design optimization problem of electric motors are highlighted. The last part will evaluate the different categories of optimization methods with respect to the criteria: degrees of freedom, computing time and the required user experience. As will be seen, there is a conflict of objectives regarding the criteria mentioned above. Requirements, which a new optimization method has to fulfil in order to solve the conflict of objectives will be presented in this last paper.

scholarly journals Kinetic electronics: Monolithic processing of a layered flexible robotic actuator film for simple film microrobot fabrication

2021 ◽  
Author(s):  
Shiyi Zhang ◽  
Joseph Wang ◽  
Kenshi Hayashi ◽  
Fumihiro Sassa
Keyword(s):  
Mass Production ◽  
Degrees Of Freedom ◽  
Complex Structure ◽  
Robotic Systems ◽  
Durability Test ◽  
Electrical Circuits ◽  
Multiple Degrees Of Freedom ◽  
The Past ◽  
Cmos Compatible ◽  
Simple Film

Abstract Low-invasive soft robotic techniques can potentially be used for developing next-generation body–machine interfaces. Most soft robots require complicated fabrication processes involving 3D printing and bonding/assembling. In this letter, we describe a monolithic soft microrobot fabrication process for the mass production of soft film robots with a complex structure by simple 2D processing of a robotic actuator film. The 45 μg/mm^2 lightweight film robot can be driven at a voltage of CMOS compatible 5 V with 0.15 mm^-1 large curvature changes; it can generate a force 5.7 times greater than its self-weight. In a durability test, actuation could be carried out over 8000 times without degradation. To further demonstrate this technique, three types of film robots with multiple degrees of freedom and moving illuminator robot were fabricated. This technique can easily integrate various electrical circuits developed in the past to robotic systems and can be used for developing advanced wearable sensing devices; It can be called “Kinetic electronics.”

An approach towards decentralized control of cooperating non-autonomous multiple robots

Robotica ◽  
2000 ◽  
Vol 18 (5) ◽  
pp. 495-504 ◽  
Author(s):  
Khalid Munawar ◽  
Masayoshi Esashi ◽  
Masaru Uchiyama
Keyword(s):  
Decentralized Control ◽  
Degrees Of Freedom ◽  
Real Life ◽  
Robotic Systems ◽  
Present System ◽  
Multiple Robots ◽  
Experimental Implementation ◽  
Control Scheme ◽  
The Common ◽  
Event Based

This paper introduces an event-based decentralized control scheme for the cooperation between multiple manipulators. This is in contrast to the common practice of using only centralized controls for such cooperation which, consequently, greatly limit the flexibility of robotic systems. The manipulators used in the present system are very simple with only two degrees of freedom, while even one of them is passive. Moreover these manipulators use very few and commonly available sensors only. Computer simulations indicated the applicability of the event-based decentralized control scheme for multi-manipulator cooperation, while real-life experimental implementation has proved that the proposed decentralized control scheme is fairly applicable for very simple and even under-actuated systems too. Hence, this work has opened new doors towards further research in this area. The proposed control scheme is expected to be equally applicable for any mobile or immobile multi-robotic system.

scholarly journals Lower Extremity Motor Impairments in Ambulatory Chronic Hemiparetic Stroke: Evidence for Lower Extremity Weakness and Abnormal Muscle and Joint Torque Coupling Patterns

2017 ◽  
Vol 31 (9) ◽  
pp. 814-826 ◽  
Author(s):  
Natalia Sánchez ◽  
Ana Maria Acosta ◽  
Roberto Lopez-Rosado ◽  
Arno H. A. Stienen ◽  
Julius P. A. Dewald
Keyword(s):  
Lower Extremity ◽  
Degrees Of Freedom ◽  
Joint Torque ◽  
Motor Impairments ◽  
Lower Extremity Weakness ◽  
Joint Torques ◽  
Hemiparetic Stroke ◽  
Chronic Hemiparetic Stroke ◽  
Hip Extension ◽  
Flexion And Extension

Although global movement abnormalities in the lower extremity poststroke have been studied, the expression of specific motor impairments such as weakness and abnormal muscle and joint torque coupling patterns have received less attention. We characterized changes in strength, muscle coactivation and associated joint torque couples in the paretic and nonparetic extremity of 15 participants with chronic poststroke hemiparesis (age 59.6 ± 15.2 years) compared with 8 age-matched controls. Participants performed isometric maximum torques in hip abduction, adduction, flexion and extension, knee flexion and extension, ankle dorsi- and plantarflexion and submaximal torques in hip extension and ankle plantarflexion. Surface electromyograms (EMGs) of 10 lower extremity muscles were measured. Relative weakness (paretic extremity compared with the nonparetic extremity) was measured in poststroke participants. Differences in EMGs and joint torques associated with maximum voluntary torques were tested using linear mixed effects models. Results indicate significant poststroke torque weakness in all degrees of freedom except hip extension and adduction, adductor coactivation during extensor tasks, in addition to synergistic muscle coactivation patterns. This was more pronounced in the paretic extremity compared with the nonparetic extremity and with controls. Results also indicated significant interjoint torque couples during maximum and submaximal hip extension in both extremities of poststroke participants and in controls only during maximal hip extension. Additionally, significant interjoint torque couples were identified only in the paretic extremity during ankle plantarflexion. A better understanding of these motor impairments is expected to lead to more effective interventions for poststroke gait and posture.

A bio-inspired robotic climbing robot to understand kinematic and morphological determinants for an optimal climbing gait

2021 ◽  
Author(s):  
Hendrik Beck ◽  
Johanna J Schultz ◽  
Christofer J Clemente
Keyword(s):  
Optimal Parameter ◽  
Legged Locomotion ◽  
Robotic Systems ◽  
Climbing Robot ◽  
Kinematic Parameters ◽  
Phase Dynamics ◽  
Complex Interactions ◽  
Optimal Dynamic ◽  
Speed Stability ◽  
Robotic Applications

Abstract Robotic systems for complex tasks, such as search and rescue or exploration, are limited for wheeled designs, thus the study of legged locomotion for robotic applications has become increasingly important. To successfully navigate in regions with rough terrain, a robot must not only be able to negotiate obstacles, but also climb steep inclines. Following the principles of biomimetics, we developed a modular bio-inspired climbing robot, named X4, which mimics the lizard’s bauplan including an actuated spine, shoulders, and feet which interlock with the surface via claws. We included the ability to modify gait and hardware parameters and simultaneously collect data with the robot’s sensors on climbed distance, slip occurrence and efficiency. We first explored the speed-stability trade-off and its interaction with limb swing phase dynamics, finding a sigmoidal pattern of limb movement resulted in the greatest distance travelled. By modifying foot orientation, we found two optima for both speed and stability, suggesting multiple stable configurations. We varied spine and limb range of motion, again showing two possible optimum configurations, and finally varied the centre of pro- and retraction on climbing performance, showing an advantage for protracted limbs during the stride. We then stacked optimal regions of performance and show that combining optimal dynamic patterns with either foot angles or ROM configurations have the greatest performance, but further optima stacking resulted in a decrease in performance, suggesting complex interactions between kinematic parameters. The search of optimal parameter configurations might not only be beneficial to improve robotic in-field operations but may also further the study of the locomotive evolution of climbing of animals, like lizards or insects.

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