scholarly journals Single Task Optimization-Based Planar Box Delivery Motion Simulation and Experimental Validation

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Yujiang Xiang ◽  
Shadman Tahmid ◽  
Paul Owens ◽  
James Yang
Keyword(s):  
Joint Angle ◽  
Inverse Dynamics ◽  
Optimization Method ◽  
Joint Torque ◽  
Motion Simulation ◽  
Single Task ◽  
Joint Torques ◽  
Time Integral ◽  
Design Variables ◽  
Complicated Task

Abstract Box delivery is a complicated task and it is challenging to predict the box delivery motion associated with the box weight, delivering speed, and location. This paper presents a single task-based inverse dynamics optimization method for determining the planar symmetric optimal box delivery motion (multi-task jobs). The design variables are cubic B-spline control points of joint angle profiles. The objective function is dynamic effort, i.e., the time integral of the square of all normalized joint torques. The optimization problem includes various constraints. Joint angle profiles are validated through experimental results using root-mean-square-error (RMSE) and Pearson’s correlation coefficient. This research provides a practical guidance to prevent injury risks in joint torque space for workers who lift and deliver heavy objects in their daily jobs.

Two-Dimensional Team Lifting Prediction With Different Box Weights

2020 ◽  
Author(s):  
Asif Arefeen ◽  
Yujiang Xiang
Keyword(s):  
Joint Angle ◽  
Inverse Dynamics ◽  
Reaction Force ◽  
Optimization Method ◽  
Two Dimensional ◽  
Dynamics Modeling ◽  
Floating Base ◽  
Grasping Forces ◽  
Design Variables ◽  
Grasping Force

Abstract A novel multibody dynamics modeling method is proposed for two-dimensional (2D) team lifting prediction. The box itself is modeled as a floating-base rigid body in Denavit-Hartenberg representation. The interactions between humans and box are modeled as a set of grasping forces which are treated as unknowns (design variables) in the optimization formulation. An inverse-dynamics-based optimization method is used to simulate the team lifting motion where the dynamic effort of two humans is minimized subjected to physical and task-based constraints. The design variables are control points of cubic B-splines of joint angle profiles of two humans and the box, and the grasping forces between humans and the box. Two numerical examples are successfully simulated with different box weights (20 Kg and 30 Kg, respectively). The humans’ joint angle, torque, ground reaction force, and grasping force profiles are reported. The joint angle profiles are validated with the experimental data.

Three-dimensional asymmetric maximum weight lifting prediction considering dynamic joint strength

2021 ◽  
pp. 095441192098703
Author(s):  
Rahid Zaman ◽  
Yujiang Xiang ◽  
Jazmin Cruz ◽  
James Yang
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Three Dimensional ◽  
Optimization Method ◽  
Weight Lifting ◽  
Joint Torque ◽  
Maximum Weight ◽  
Angular Velocities ◽  
Asymmetric Lifting

In this study, the three-dimensional (3D) asymmetric maximum weight lifting is predicted using an inverse-dynamics-based optimization method considering dynamic joint torque limits. The dynamic joint torque limits are functions of joint angles and angular velocities, and imposed on the hip, knee, ankle, wrist, elbow, shoulder, and lumbar spine joints. The 3D model has 40 degrees of freedom (DOFs) including 34 physical revolute joints and 6 global joints. A multi-objective optimization (MOO) problem is solved by simultaneously maximizing box weight and minimizing the sum of joint torque squares. A total of 12 male subjects were recruited to conduct maximum weight box lifting using squat-lifting strategy. Finally, the predicted lifting motion, ground reaction forces, and maximum lifting weight are validated with the experimental data. The prediction results agree well with the experimental data and the model’s predictive capability is demonstrated. This is the first study that uses MOO to predict maximum lifting weight and 3D asymmetric lifting motion while considering dynamic joint torque limits. The proposed method has the potential to prevent individuals’ risk of injury for lifting.

Physics-Based Seated Posture Prediction for Pregnant Women and Validation Considering Ground and Seat Pan Contacts

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Bradley Howard ◽  
Aimee Cloutier ◽  
Jingzhou (James) Yang
Keyword(s):  
Pregnant Women ◽  
Objective Function ◽  
Linear Regression Analysis ◽  
Joint Torque ◽  
Joint Torques ◽  
Design Variables ◽  
Optimization Formulation ◽  
Posture Prediction ◽  
Seated Posture ◽  
End Effectors

An understanding of human seated posture is important across many fields of scientific research. Certain demographics, such as pregnant women, have special postural limitations that need to be considered. Physics-based posture prediction is a tool in which seated postures can be quickly and thoroughly analyzed, as long the predicted postures are realistic. This paper proposes and validates an optimization formulation to predict seated posture for pregnant women considering ground and seat pan contacts. For the optimization formulation, the design variables are joint angles (posture); the cost function is dependent on joint torques. Constraints include joint limits, joint torque limits, the distances from the end-effectors to target points, and self-collision avoidance constraints. Three different joint torque cost functions have been investigated to account for the special postural characteristics of pregnant women and consider the support reaction forces (SRFs) associated with seated posture. Postures are predicted for three different reaching tasks in common reaching directions using each of the objective function formulations. The predicted postures are validated against experimental postures obtained using motion capture. A linear regression analysis was used to evaluate the validity of the predicted postures and was the criteria for comparison between the different objective functions. A 56 degree of freedom model was used for the posture prediction. Use of the objective function minimizing the maximum normalized joint torque provided an R2 value of 0.828, proving superior to either of two alternative functions.

Design Human-Robot Collaborative Lifting Task Using Optimization

2021 ◽  
Author(s):  
Asif Arefeen ◽  
Yujiang Xiang
Keyword(s):  
Degrees Of Freedom ◽  
Joint Angle ◽  
Joint Torque ◽  
Robotic Arm ◽  
Inverse Dynamic ◽  
Floating Base ◽  
Grasping Forces ◽  
Design Variables ◽  
Human Arm ◽  
Lifting Task

Abstract In this paper, an optimization-based dynamic modeling method is used for human-robot lifting motion prediction. The three-dimensional (3D) human arm model has 13 degrees of freedom (DOFs) and the 3D robotic arm (Sawyer robotic arm) has 10 DOFs. The human arm and robotic arm are built in Denavit-Hartenberg (DH) representation. In addition, the 3D box is modeled as a floating-base rigid body with 6 global DOFs. The interactions between human arm and box, and robot and box are modeled as a set of grasping forces which are treated as unknowns (design variables) in the optimization formulation. The inverse dynamic optimization is used to simulate the lifting motion where the summation of joint torque squares of human arm is minimized subjected to physical and task constraints. The design variables are control points of cubic B-splines of joint angle profiles of the human arm, robotic arm, and box, and the box grasping forces at each time point. A numerical example is simulated for huma-robot lifting with a 10 Kg box. The human and robotic arms’ joint angle, joint torque, and grasping force profiles are reported. These optimal outputs can be used as references to control the human-robot collaborative lifting task.

Biomechanical Model of the Press Handstand in Gymnastics

1988 ◽  
Vol 4 (4) ◽  
pp. 326-341 ◽  
Author(s):  
Spiros G. Prassas
Keyword(s):  
Shoulder Joint ◽  
Joint Angle ◽  
Wrist Joint ◽  
Center Of Mass ◽  
Biomechanical Model ◽  
Joint Torque ◽  
Joint Torques ◽  
Skilled Performance ◽  
The Press ◽  
Line Passing

A biomechanical model of the press handstand was developed to evaluate and predict the shoulder joint torque requirements as well as the motion of a gymnast’s center of mass (CM) from an initial to a final (handstand) position. Five press handstands executed by gymnasts of differing abilities were filmed and analyzed. The results were compared to the predicted parameters of simulated presses. It was found that execution of the skill with fewer fluctuations in trunk and lower extremities angular velocity—a characteristic of skilled performance—required smoother and at times larger shoulder joint torques. Reduction of the hip joint angle by only 5 or 10° did not substantially reduce the shoulder joint torque requirements. Regarding CM motion, it was found that during performance the CM continuously elevated and remained close to a vertical line passing through the center of the wrist joint. All gymnasts, however, were found to be leaning slightly backward during the first part of the movement and slightly forward during the later phases. Modifications in wrist joint angle required to maintain each gymnast’s CM precisely above the center of the wrist joint were investigated.

Women Ankle Joint Torques Comparison between Bare Foot and High Heel

2013 ◽  
Vol 378 ◽  
pp. 382-386
Author(s):  
Hai Bin Liu ◽  
Zhi Qiang He ◽  
Wen Xue Yuan ◽  
Zhao Li Meng
Keyword(s):  
Ankle Joint ◽  
Muscle Force ◽  
Inverse Dynamics ◽  
Frontal Plane ◽  
Joint Torque ◽  
Force System ◽  
Joint Torques ◽  
High Heel ◽  
Internal Phase ◽  
The Stability

Objective: Research on ankle joint torques of healthy women with high heel compared with bare foot based on Inverse Dynamics. Methods: 12 women were recruited and tested by motion and force system. Kinematical, kinetic and personal segment parameter data were used to compute ankle joint torques and compare the differences between bare foot and high heel.Conclusion: compared with bare foot, It can infer that Soleus and Gastrocnemius access the contraction in advance and keep higher muscle force. Tibia Anterior and Posterior must have to make powerful contraction that could keep the ankle joint with higher torque. Compared with sagital and frontal plane, high heel doesnt change the joint torque in horizontal plane during the whole internal phase, but the fluctuations of torque value may influence the stability during normal level walking.

Improving Net Joint Torque Calculations Through a Two-Step Optimization Method for Estimating Body Segment Parameters

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Raziel Riemer ◽  
Elizabeth T. Hsiao-Wecksler
Keyword(s):  
Inverse Dynamics ◽  
Optimization Problems ◽  
Joint Torque ◽  
Optimization Approach ◽  
Regression Equations ◽  
Random Errors ◽  
Body Segment ◽  
Joint Torques ◽  
Body Segment Parameters ◽  
True Values

Two main sources of error in inverse dynamics based calculations of net joint torques are inaccuracies in segmental motions and estimates of anthropometric body segment parameters (BSPs). Methods for estimating BSP (i.e., segmental moment of inertia, mass, and center of mass location) have been previously proposed; however, these methods are limited due to low accuracies, cumbersome use, need for expensive medical equipment, and∕or sensitivity of performance. This paper proposes a method for improving the accuracy of calculated net joint torques by optimizing for subject-specific BSP in the presence of characteristic and random errors in motion data measurements. A two-step optimization approach based on solving constrained nonlinear optimization problems was used. This approach minimized the differences between known ground reaction forces (GRFs), such as those measured by a force plate, and the GRF calculated via a top-down inverse dynamics approach. In step 1, a series of short calibration motions was used to compute first approximations of optimized segment motions and BSP for each motion. In step 2, refined optimal BSPs were derived from a combination of these motion profiles. We assessed the efficacy of this approach using a set of reference motions in which the true values for the BSP, segment motion, GRF, and net joint torques were known. To imitate real-world data, we introduced various noise conditions on the true motion and BSP data. We compared the root mean squared errors in calculated net joint torques relative to the true values due to the optimal BSP versus traditionally-derived BSP (from anthropometric tables derived from regression equations) and found that the optimized BSP reduced the error by 77%. These results suggest that errors in calculated net joint torques due to traditionally-derived BSP estimates could be reduced substantially using this optimization approach.

scholarly journals On the Organizing Role of Nonmuscular Forces During Performance of a Giant Circle in Gymnastics

2012 ◽  
Vol 28 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Violaine Sevrez ◽  
Guillaume Rao ◽  
Eric Berton ◽  
Reinoud J. Bootsma
Keyword(s):  
Muscle Force ◽  
Inverse Dynamics ◽  
Joint Torque ◽  
Hip Joints ◽  
Joint Torques ◽  
Kinematic Pattern ◽  
Triple Pendulum ◽  
Inverse Dynamics Analysis ◽  
Induced Changes

Five elite gymnasts performed giant circles on the high bar under different conditions of loading (without and with 6-kg loads attached to the shoulders, waist or ankles). Comparing the gymnasts’ kinematic pattern of movement with that of a triple-pendulum moving under the sole influence of nonmuscular forces revealed qualitative similarities, including the adoption of an arched position during the downswing and a piked position during the upswing. The structuring role of nonmuscular forces in the organization of movement was further reinforced by the results of an inverse dynamics analysis, assessing the contributions of gravitational, inertial and muscular components to the net joint torques. Adding loads at the level of the shoulders, waist or ankles systematically influenced movement kinematics and net joint torques. However, with the loads attached at the level of the shoulders or waist, the load-induced changes in gravitational and inertial torques provided the required increase in net joint torque, thereby allowing the muscular torques to remain unchanged. With the loads attached at the level of the ankles, this was no longer the case and the gymnasts increased the muscular torques at the shoulder and hip joints. Together, these results demonstrate that expert gymnasts skillfully exploit the operative nonmuscular forces, employing muscle force only in the capacity of complementary forces needed to perform the task.

Predictive Simulation of Human Ladder Climbing

2013 ◽  
Author(s):  
Hyun-Joon Chung ◽  
Yujiang Xiang ◽  
Mahdiar Hariri ◽  
Rajan Bhatt ◽  
Jasbir S. Arora ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Mechanical Energy ◽  
Joint Torque ◽  
Human Model ◽  
Joint Torques ◽  
Contact Points ◽  
Design Variables ◽  
Reaction Forces ◽  
Hands And Feet

An optimization formulation for human ladder climbing simulation is presented. The human model has 55 degrees of freedom — 49 revolute joints and 6 global translation & rotation joints. It is assumed that the ladder climbing motion is symmetric and periodic. The formulation starts with four contact points with both hands and feet. Then, hand and foot moves up and it ends with four contact points again. Design variables are the joint angle profiles and contact reaction forces. The objective function is combined with dynamic efforts and motion tracking. The dynamic efforts are joint torque square which is proportional to the mechanical energy. The motion tracking is the motion capture data tracking so that the motion follows the natural ladder climb motion as well. The dynamics results with joint torques and reaction forces are recovered and analyzed from the simulation.

Design a Four-Bar Linkage for Upper Limb Muscle Rehabilitation Exercise: A Simulation Study

2020 ◽  
Author(s):  
Joel Quarnstrom ◽  
Yujiang Xiang
Keyword(s):  
Inverse Dynamics ◽  
Optimization Method ◽  
Joint Torque ◽  
Motion Exercise ◽  
Arm Muscles ◽  
Specific Muscle ◽  
Different Shapes ◽  
Arm Motion ◽  
Four Bar Linkage ◽  
Rehabilitation Exercise

Abstract In this study, a four-bar linkage with coupler point is designed to guide the arm motion exercise for muscle strength rehabilitation. The hand grasps the coupler point during rotation. The coupler point can generate different shape of trajectories by changing the coupler point’s relative location and the linkage’s dimensions. The rotating coupler point is used to guide the user’s hand to exercise arm muscles for rehabilitation. A two-dimensional (2D) musculoskeletal arm model is used to simulate the arm motion. The inverse-dynamics-based optimization method is used for trajectory reconstruction to determine the joint torque and muscle forces. The effect of different shapes of coupler point trajectory on specific muscle force excise is investigated, such as kidney shape, heart shape, and woven shape trajectories.

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