Open Kinematic Chain Research Articles

THE DESIGN OF MOVEMENT OF THE ROBOT MODEL IN STRUCTURED ENVIRONMENT USING MSC ADAMS

In this work, the issue of kinematic analysis of the open kinematic chain of an industrial robot is discussed. The aim of the work lies in the kinematic analysis of the robot and the display of kinematic quantities in the work process. Transformation matrices of coordinate systems of individual members are determined for the solution by the matrix method. The direct method of kinematics using the MSC Adams View program is solved. The result is a graphical representation of the kinematic variables of the mechanical system of the end point of the effector and trajectory when moving in its working space.

Modeling of Inverse Kinematic of 3-DoF Robot, Using Unit Quaternions and Artificial Neural Network

SUMMARYThis paper presents a novel method for modeling a 3-degree of freedom open kinematic chain using quaternions algebra and neural network to solve the inverse kinematic problem. The structure of the network was composed of 3 hidden layers with 25 neurons per layer and 1 output layer. The network was trained using the Bayesian regularization backpropagation. The inverse kinematic problem was modeled as a system of six nonlinear equations and six unknowns. Finally, both models were tested using a straight path to compare the results between the Newton–Raphson method and the network training.

COMPUTER MODELING IN MSC ADAMS/VIEW AS PART OF A MODERN APPROACH TO THE DESIGN OF MECHANICAL SYSTEMS OF ROBOTS

The presented paper deals with the use of computer simulation in the design of a robot model with 4 degrees of freedom of movement. The MSC Adams program is used in the computer simulation, and the use of the Matlab program is also shown. The robot's mechanism is an open kinematic chain. During kinematic analysis, attention is paid to solving the direct problem of kinematics in MSC Adams and in Matlab. The result of the solution is the calculated trajectory of the movement of the selected point of the end effector. The trajectory is shown in graphical form. In Matlab, the magnitude of the position vector of the effector point is calculated as a function of time at the selected course of angular deflection in individual kinematic pairs at constant angular velocities in individual joints of the robot.

Function of the Upper Member in Stroke

Modern physical therapy is based on the idea that function governs the organ. This aspect can explain why the main activity of the hand is gripping and grasping and the main function of the foot is walking. The upper limbs use the movement in an open kinematic chain and have a very large representation at the central level, while the lower limbs work in a closed kinematic chain. We continue to face limitations in the recovery and interdisciplinary recovery of upper limb function in stroke, even though we currently have sufficient scientific evidence and therapeutic ways to stimulate healing. The research aims to identify whether a person suffering from an ischemic stroke can change the function of the affected upper limb three months after the accident by starting or continuing the recovery program until the patient leaves the acute phase.

Tek Mıknatıs aracığılı ile bir Manyetotaktik Bakterinin Adaptif Manevra Kontrolü için Bağımsız Eklem Kontrol Simulasyonları

The use of micro-robotic systems in non-invasive medicine has been heavily promoted in the literature for the last decade. The studies usually focus on artificial or biohybrid microswimmers of various origins subject to the effect of an external electromagnetic field controlled by a computer. Although there exist several motion control studies shared to date, control of a bio-hybrid microswimmer has rarely been demonstrated employing an open kinematic chain, in detail. In this work, motion control of an isolated magnetotactic bacterium cell (Magnetospirillum Gryphiswaldens) is presented via a magnetic field actively positioned by an open kinematic chain. The cell is modeled with its complete environment to make it as realistic as possible along with the magnetic torque, which is induced by a single magnet attached at the end effector of a robotic arm, exerted on it for maneuvering control. The control is based on a proportional – integral – derivative (PID) gain scheme with adaptive integral gain to focus on a particular steady-state error with discontinuous reference signals. The control signal is transformed into pulse width modulation (PWM) signals to drive the motors articulating the joints of the open kinematic chain, the inverse kinematics of which is designed to be simple enough to achieve independent joint control. A numerical analysis of the coupled system is carried out in the time domain. The performance of the said motion control approach is investigated for each degree of freedom for the planar motion of the microswimmer. Simulations demonstrate a planar open kinematic chain is capable of control the gait of the microswimmer while following its trajectory near a planar boundary via independent joint control. Furthermore, simulations demonstrate that the effective magnetic inertia and the shear stress results in a small but certain lag in the motion control performance of the overall system.

Bilateral control simulations for a pair of magnetically-coupled robotic arm and bacterium for in vivo applications

There are several in vivo and in vitro control performances with artificial micro-swimmers; however, control of a biohybrid micro-swimmer using an open kinematic chain remains fairly untouched to this date. In this work, non-contact maneuvering control of a single magnetotactic bacterium cell is simulated under in vivo conditions of a synovial joint with associated physical properties of the respective synovial cavity. A very detailed mathematical model representing in vivo swimming conditions of an actual bacterium cell is built followed by a PID control scheme with adaptive integral gains. The performance of the control law is presented with the help of time-dependent errors to different yaw-angle references accompanied by the time-dependent states of the coupled system. The results show that the proposed control law is capable of adjusting the heading, i.e., yaw-angle, of the simulated magnetotactic bacterium species, i.e., Magnetospirillum Gryphiswaldense, moving at proximity to a curved surface, i.e., the inner surface of the synovial joint in a Homo sapiens. The results further demonstrate that it is possible to achieve set-point tracking against both constant and time-dependent references.

Backstepping Control of Open-Chain Linkages Actuated by Antagonistic Hill Muscles

Abstract For human–machine interaction, the forward progression of technology, particularly controls, regularly brings about new possibilities. Indeed, healthcare applications have flourished in recent years, including robotic rehabilitation, exercise, and prosthetic devices. Testing these devices with human subjects is inherently risky and frequently inconsistent. This work offers a novel simulation framework toward overcoming many of these difficulties. Specifically, generating a closed-loop dynamic model of a human or a human subsystem that can connect to device simulations allows simulated human–machine interaction. In this work, a muscle-actuated open kinematic chain linkage is generated to simulate the human, and a backstepping controller based on inverse dynamics is derived. The control architecture directly addresses muscle redundancy, and two options to resolve this redundancy are evaluated. The specific case of a muscle-actuated arm linkage is developed to illustrate the framework. Trajectory tracking is achieved in simulation. The muscles recruited to meet the tracking goal are in agreement with the method used to solve the redundancy problem. In the future coupling such simulations to any relevant simulation of a machine will provide safe, insightful preprototype test results.

Effectiveness of Open Kinematic Chain Exercises and Closed Kinematic Chain Exercises in Adductor Groin Pain in Recreational Football Players

Background: Football has been growing considerably for the past decade in India. Many young adults have taken up football as their passion. However, the grounds are underdeveloped with limited number of facilities required for a safe game. Coaching facilities are inadequate and thus fail to provide basic information about the precautions to be taken during play or the necessary steps to be taken post injury. This leads to increased risk of injuries. Groin injuries comprise of 10-18% of all football injuries. Objective: The objective of the study was to compare the effects of open and CKC exercises on groin injuries in young adults who play football for recreation. Pain Assessment, Tenderness assessment and MMT were used for assessing the individuals. Method: There were total 40 subjects who were willing participants of this study of which 3 dropped out. This was a study conducted to find the effects of open and CKC exercises on groin injuries in young adults who play football for recreation. Here we evaluated the pain using VAS and tenderness grading. Muscle strength was assessed using MMT. Result: There was a significant effect of open and CKC exercises on groin injuries. There was a reduction of pain; both on activity as well as on resistance(p=0.0065 and 0.0235) respectively. Tenderness was also less (p= 0.0130). Muscle strength did not show any significant change (p= 0.1775) Conclusion: There is a significant effect of OKC and CKC exercises being administered together rather than giving only CKC exercises on reducing pain and reducing the risk of injuries in recreational football players.

Моделирование упругих древовидных динамических систем при наличии внешних голономных связей

Modern scientific literature pays close attention to the problems of optimal modeling of elastic dynamic systems. The symbolic-recursive model of Newton --- Euler method with the provision of computational algorithms with a degree of complexity proportional to the dimension of these systems, i.e., O(n), has been adapted for dynamic systems with open kinematic chains, in particular, for elastic manipulators. If dynamic systems have closed kinematic chains, it is extremely difficult to propagate the strategy of numerical analysis without the mass matrix inversion. Consequently, the task of optimal modeling of tree-like dynamic systems is reduced to the search for combined strategies that use the procedures of strategies with and without inversion of mass matrices simultaneously. The paper introduces a method of numerical dynamic analysis of elastic tree-like multilink systems, the method combining the procedure of inverting the mass matrix with the procedure of effective kinematic calculation, borrowed from the generalized Newton --- Euler method. An approximate dynamic analysis technique is proposed that fully reproduces the recursive procedures of the generalized Newton --- Euler method. The technique is confirmed to the extent that the period of inversion of these systems is less than the time of their full functioning, and the range of displacements during one cycle is less than the complete revolution of the mechanism. The use of the approximate method for the dynamic analysis of elastic mechanisms is considered using the example of a numerical dynamic calculation of a slider-crank mechanism with an elastic connecting rod

Influence of closed Kinematic chain exercise versus open Kinematic Chain Exercise on Q-Angle in subjects with Osteoarthritis Knee

Influence of closed Kinematic chain exercise versus open Kinematic Chain Exercise on Q-Angle in subjects with Osteoarthritis Knee

A recursive algorithm for dynamics of multiple frictionless impact-contacts in open-loop robotic mechanisms

In this paper, the phenomenon of multiple impact-contacts has been dynamically modeled for an open kinematic chain with rigid links and revolute joints. The dynamic equations of the mentioned system have been extracted based on the recursive Gibbs–Appell formulation. The impact-contact phenomenon has been formulated by the regularized method in which the force of impact is a continuous function of the relative penetration and relative velocity of two colliding surfaces with respect to each other. The geometrical specifications and the mechanical properties of colliding surfaces are the two main parameters used in the modeling of viscoelastic contact force models. In this work, a recursive algorithm, which has been developed based on 3 × 3 rotation matrices to reduce the computational load, symbolically derives the motion equations of a multibody system that collides with surrounding surfaces at several points. The system under study includes the non-impact (flight) phase and the impact phase. Going from the flight phase to the impact phase and back, detecting the exact moment of impact, and also solving the differential equations of motion during a very short impact time have their particular challenges and complexities, which are dealt with in this work. In the next step, nine famous contact force models have been compared in order to select the most suitable model for simulation work. Finally, to show the accuracy and the capability of the presented algorithm, the dynamic behavior of an open-chain robotic mechanism consisting of 4 rigid links connected by revolute joints has been simulated and analyzed.

Designing Statically Determinable Mechanisms of Technological Mechatronic Machines with Parallel Kinematics

The work is devoted to improving the reliability and manufacturability of mechatronic machine designs with parallel kinematics by replacing statically indeterminable manipulators with statically determinable mechanisms. A technique is proposed in which the design of statically determinable manipulators of technological mechatronic machines with parallel kinematics is performed by modifying the structure of prototypes and includes three steps: identifying and analyzing redundant links, eliminating redundant links, checking the correctness of eliminating redundant links. To determine the number of degrees of freedom of the mechanism, identify redundant links, and verify the solution, the authors use the proposed methodology for structural analysis of parallel structure mechanisms. In structural analysis, a manipulator is represented by a hierarchical structure and is considered as a parallel connection of elementary mechanisms with an open kinematic chain; as a kinematic chain consisting of leading and driven parts; as a set of links and kinematic pairs; as a kinematic connection of the output link and the rack. The article implements the following techniques for eliminating redundant links: mobility increase in kinematic pairs; introduction of unloading links and passive kinematic pairs to the kinematic chain; exclusion of extra links and pairs from the kinematic chain; increase in mobility in some kinematic pairs simultaneously with the exclusion of other kinematic pairs that have become superfluous. The authors developed several variants of structural schemes of self-aligning manipulators based on the Orthoglide mechanism, which retain the basic functional proper ties of the prototype. To increase the number of self-aligning mechanism diagrams, the redistribution of mobilities and links within the connecting kinematic chain and between connecting kinematic chains is used. The proposed methodics allow to determine the number of degrees of freedom of the mechanism, the number and type of redundant links, eliminate redundant links and, on an alternative basis, build structural diagrams of statically determinable mechanisms of technological mechatronic machines with parallel kinematics.

Learning bioinspired joint geometry from motion capture data of bat flight

Bioinspired robotic systems are often designed by assuming that the kinematics of the biological system of interest are well approximated by an open kinematic chain subject to box constraints. These box-constrains are typically generated by designer interpretation of biomotion and anatomical studies or pragmatic fabrication constraints. In contrast to this standard design paradigm, this paper presents a methodology for learning joint geometry which restricts the range of motion of generic ball joints to only the reachable set observed during biomotion experiments. This reachable set is identified by constructing an analytical-empirical potential energy function over the experimental observations. The energy function effectively ‘pushes’ configurations close to the set of observations. This energy function is then thresholded to identify the zero-potential (ZP) configuration set, and joint geometry is constructed using the resulting contour. We construct an entire bat wing using this method, and demonstrate through motion capture experiments that the learned geometry successfully restricts motions to the ZP set.

Effect of 6-week retro or forward walking program on pain, functional disability, quadriceps muscle strength, and performance in individuals with knee osteoarthritis: a randomized controlled trial (retro-walking trial)

BackgroundPrevious studies reported the beneficial effects of walking in individual with mild to moderate knee osteoarthritis (OA). The current study aimed to compare the effect of 6-week retro versus forward walking program versus control group on pain, functional disability, quadriceps muscle strength and physical performance in individuals with knee OA.MethodsA three-arm single-blinded, randomized, controlled trial and intention-to-treat analysis was conducted in outpatient physiotherapy department, King Saud University, Saudi Arabia. Sixty-eight individuals (mean age, 55.6 years; 38 female) with knee OA participated. The participants in the retro or forward walking group completed 10 min of supervised retro or forward walking training in addition to usual care, 3 days/week for 6 weeks. The control group received a routine physiotherapy program. This program comprises a combination of closed and open kinematic chain exercises, including straight leg raising, isometric quadriceps, isometric hip adduction, terminal knee extension, semi-squat, and leg press. The primary outcomes were mean pain and knee function score measured by the numerical rating scale and the Western Ontario and McMaster Universities Osteoarthritis Index, respectively. The secondary outcomes were mean score of quadriceps muscle strength and timed up and go test scores. All the outcomes were analyzed at baseline and week 6.ResultsIn total, 68 subjects participated in this 6-week randomized, controlled trial. The completion rates of the primary and secondary outcome measures at week 6 were 91, 87, and 82% in the retro walking, forward walking, and control groups, respectively. In the intention-to-treat analysis, the retro walking group had a greater reduction in pain intensity (mean changes, 1.8 versus 1; p = 0.01) and functional disability (mean changes, 4.8 versus 2.2; p = 0.008) than the control group. Similarly, the retro walking group had a greater improvement in the quadriceps muscle strength (mean changes, 1.7 kg versus 0.7 kg; p = 0.008) and the timed up and go test (mean changes, 0.6 s versus 0.1 s; p = 0.003) than the control group.ConclusionsThe 6-week retro walking program compared with forward walking or control groups resulted in greater reduction in pain and functional disability and improved quadriceps muscle strength and performance in individuals with knee OA.Trial registrationControlled Trials ISRCTN12850845, Registered 26 January 2015.

Assembly tolerance analysis based on the Jacobian model and skin model shapes

Purpose The purpose of this paper is to carry out an assembly tolerance analysis by means of a combined Jacobian model and skin model shape. The former is based on small displacements modeling of points using 6 × 6 transformation matrices of open kinematic chains in robotics. The latter easily models toleranced features with all kinds of geometric deviations. Design/methodology/approach This paper presents the procedure of performing tolerance analysis by means of the Jacobian model and skin model shape for assemblies. The point cloud-based discrete representative is able to model the actual toleranced surfaces instead of the ideal or associated ones in an assembly, which brings the simulation tools closer to reality. Findings The proposed method has the advantage of skin model shape which is suitable for geometric tolerances management along the product life cycle and contact analysis of kinematic small variations, as well as, with the Jacobian, enabling transformation of locally expressed parts deviations to globally expressed functional requirements. The result of the case study shows the accuracy of the method. Research limitations/implications The proposed approach has not been developed fully; other functional features such as the pyramid are still ongoing challenges. Practical implications It is an effective method for supporting design, manufacturing and inspection by providing a quantitative analysis of the effects of multi-tolerances on the final functional key characteristics and for predicting the quality level. Originality/value The paper is original in taking advantages of both Jacobian model and skin model shape to consider all geometric tolerances in assembly.

Comparisons of Accuracy of Knee Joint Motion During Closed verse Open Kinetic Chain Tasks in Subjects with Flexible Flatfeet

Purpose: This study examined the effects of flexible flatfeet on the accuracy of knee joint motions in closed and open kinetic chain tasks. Methods: Twenty-four healthy participants were recruited for this study. The subjects were divided into two groups using a navicular drop (ND) test: flexible flatfoot group (n=12, male: 6, aged 22.00±2.22 years) and age-matched control group (n=12, males: 6, aged 22.17±1.53 years). The accuracy of knee motion was measured quantitatively by tracing through the flexion and extension motion of the knee joints in the closed kinetic chain and the open kinetic chain. Results: There was a significant difference in the accuracy index between the groups in closed kinetic chain task, but there was no significant difference in the open kinetic chain task. In addition, there was a significant difference in the accuracy index between the closed kinetic chain and the open kinetic chain task in the flexible flatfoot group. In addition, a significant negative correlation was observed between the ND and accuracy index in the closed kinematic chain task, but there was no significant relationship between the ND and accuracy index in the open kinematic chain task. Conclusion: Flexible flatfeet can affect the accuracy of the adjacent joints, such as the knee joint in the closed kinematic chain.

Transfer of lightweight design principles from the musculoskeletal system to an engineering context

An important source for technical lightweight design is the human musculoskeletal system. The musculoskeletal lightweight design mainly results from the coordinated interplay of different principles. Prevailing solutions that use musculoskeletal lightweight design principles neglect the coordinated interplay of these principles. Moreover, transfer is limited to isolated principles. Therefore, further potential for lightweight design can be expected. Due to the kinematic similarities of the human extremities to technical systems that can be described as open kinematic chains, in this paper the lightweight design potential is examined by applying the interaction of the aforementioned lightweight design principles to technical systems. A new bioinspired approach is developed, which implements the control and optimization running synchronously in nature in a sequential approach for technology. The bioinspired approach is implemented by coupling multibody simulation and topology optimization in an iterative process. The results of the bioinspired approach show that, compared to a classical approach, mass can be saved and deformations can be minimized. The synthesized geometry is mainly optimized for compressive stresses and therefore easier to manufacture than a bending stiff structure in the classical case. The examinations in this paper do not take application-specific requirements into account. Therefore the application to special technical systems, and furthermore advantages and disadvantages of the new approach are discussed.

To compare the effectiveness of proprioceptive circuit exercises versus open kinematics chain exercises on pain and improve muscle strength and physical function in osteoarthritis knee patients

Osteoarthritis (OA) is the most common musculoskeletal condition affecting the quality of life of older adults. Aim of this experimental comparative study is to compare the effectiveness of proprioceptive circuit exercises versus open kinematics chain exercises on pain & improve muscle strength and physical function in Osteoarthritis knee patients. The data of 60 OA knee patients were collected from the Parul Sevashram Hospital, Vadodara. The patients were divided into two groups, group A was given proprioceptive circuit exercises and group B was given open kinematic chain exercises. A pretest outcome measures i.e., NPRS, MMT and WOMAC were given. Interventions were carried out for 3 weeks. The results were derived by using statistical methods with the help of statistics software Mad Calc, within group comparison “paired t test” and between group comparisons “unpaired t test” was used. There was significant differences in pretest and post values within two outcome variables of each group but there was significant differences seen when two outcome measures of each group were compared. The study showed that both groups are effective in reducing pain and improved muscle strength & physical function in knee osteoarthritis. After exercises between both groups proprioceptive circuit exercise group A was extremely statistically significant than open kinematic chain group B. So group A indicating more reducing pain and beneficial Effect on reducing pain, improved muscle strength, physical function in OA knee patients.

Manipulator for scanning of the pipes external surface

The paper presents a very simple manipulator, which can describe a circular trajectory, in order to position a scanning device for inspecting the external surface of a pipe. The open kinematic chain has only three active joints, and for equally spaced scanning positions around the pipe, its inverse kinematics is derived by help of elementary geometry. The manipulator was built as a part of a mobile robot, serving for inspection and monitoring of the pipelines in the oil and gas industry. Being a demonstrator, its joints actuators are micro RC servos, so a calibration operation of each one was also performed.

Spatially recursive estimation and Gaussian process dynamic models of bat flapping flight

Bats exhibit exceptional agility, maneuverability, and efficiency during flight due to the complex articulated multibody structure of their wings and to the nonlinear and unsteady dynamics that govern their motion. While excellent progress has been made in the study of the kinematics of bat flapping flight, there still does not exist a dynamic model which is suitable for use in state estimation. This issue is typically overcome by using a few high-frame-rate cameras to capture motion; however, such systems are expensive and prone to measurement occlusion. This paper establishes a methodology that is designed to exploit an emerging class of experimental hardware which employs low-resolution, low-cost, and highly redundant imaging networks. The redundant camera network ameliorates the issue of self-occlusion, but the large-baseline, nonlinear motion of points in image space makes tracking difficult without a suitable motion prior. To remedy this issue, this paper exploits the tree topology of the bat skeleton and introduces a conditionally independent Bayes’ filter implemented with inboard state correction. Our results show that at low frame rates, this estimator performs better than both the standard and conditionally independent without inboard correction approaches for state estimation of an open kinematic chain. In addition to the estimation strategy, we construct a Gaussian process dynamic model (GPDM) of flight dynamics which we will use in future work as a suitable motion prior for state estimation. The GPDM presented in this paper is the first nonlinear dimensionality reduction of bat flight.