scholarly journals Joint Torque Prediction via Hybrid Neuromusculoskeletal Modelling during Gait Using Statistical Ground Reaction Estimates: An Exploratory Study

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6597
Author(s):  
Shui Kan Lam ◽  
Ivan Vujaklija
Keyword(s):  
Real World ◽  
Inverse Dynamics ◽  
Joint Torque ◽  
Force Measurements ◽  
Estimation Errors ◽  
Clinical Indicators ◽  
Musculoskeletal Modelling ◽  
Joint Torques ◽  
Biomechanical Models ◽  
Reaction Forces

Joint torques of lower extremity are important clinical indicators of gait capability. This parameter can be quantified via hybrid neuromusculoskeletal modelling that combines electromyography-driven modelling and static optimisation. The simulations rely on kinematics and external force measurements, for example, ground reaction forces (GRF) and the corresponding centres of pressure (COP), which are conventionally acquired using force plates. This bulky equipment, however, hinders gait analysis in real-world environments. While this portability issue could potentially be solved by estimating the parameters through machine learning, the effect of the estimation errors on joint torque prediction with biomechanical models remains to be investigated. This study first estimated GRF and COP through feedforward artificial neural networks, and then leveraged them to predict lower-limb sagittal joint torques via (i) inverse dynamics and (ii) hybrid modelling. The approach was evaluated on five healthy subjects, individually. The predicted torques were validated with the measured torques, showing that hip was the most sensitive whereas ankle was the most resistive to the GRF/COP estimates for both models, with average metrics values being 0.70 < R2 < 0.97 and 0.069 < RMSE < 0.15 (Nm/kg). This study demonstrated the feasibility of torque prediction based on personalised (neuro)musculoskeletal modelling using statistical ground reaction estimates, thus providing insights into potential real-world mobile joint torque quantification.

A Least-Squares Estimation Approach to Improving the Precision of Inverse Dynamics Computations

1998 ◽  
Vol 120 (1) ◽  
pp. 148-159 ◽  
Author(s):  
A. D. Kuo
Keyword(s):  
Least Squares ◽  
Inverse Dynamics ◽  
Weighted Least Squares ◽  
Euler Method ◽  
Measured Data ◽  
Joint Torque ◽  
Ground Reaction Forces ◽  
Joint Torques ◽  
Wide Range ◽  
Reaction Forces

A least-squares approach to computing inverse dynamics is proposed. The method utilizes equations of motion for a multi-segment body, incorporating terms for ground reaction forces and torques. The resulting system is overdetermined at each point in time, because kinematic and force measurements outnumber unknown torques, and may be solved using weighted least squares to yield estimates of the joint torques and joint angular accelerations that best match measured data. An error analysis makes it possible to predict error magnitudes for both conventional and least-squares methods. A modification of the method also makes it possible to reject constant biases such as those arising from misalignment of force plate and kinematic measurement reference frames. A benchmark case is presented, which demonstrates reductions in joint torque errors on the order of 30 percent compared to the conventional Newton–Euler method, for a wide range of noise levels on measured data. The advantages over the Newton–Euler method include making best use of all available measurements, ability to function when less than a full complement of ground reaction forces is measured, suppression of residual torques acting on the top-most body segment, and the rejection of constant biases in data.

scholarly journals Inverse and forward dynamics: models of multi–body systems

2003 ◽  
Vol 358 (1437) ◽  
pp. 1493-1500 ◽  
Author(s):  
E. Otten
Keyword(s):  
Inverse Dynamics ◽  
Temporal Patterns ◽  
Forward Dynamics ◽  
Muscle Forces ◽  
Complex Behaviour ◽  
Joint Torques ◽  
Advantages And Disadvantages ◽  
Reaction Forces ◽  
Internal Forces ◽  
Multi Body

Connected multi–body systems exhibit notoriously complex behaviour when driven by external and internal forces and torques. The problem of reconstructing the internal forces and/or torques from the movements and known external forces is called the ‘inverse dynamics problem’, whereas calculating motion from known internal forces and/or torques and resulting reaction forces is called the ‘forward dynamics problem’. When stepping forward to cross the street, people use muscle forces that generate angular accelerations of their body segments and, by virtue of reaction forces from the street, a forward acceleration of the centre of mass of their body. Inverse dynamics calculations applied to a set of motion data from such an event can teach us how temporal patterns of joint torques were responsible for the observed motion. In forward dynamics calculations we may attempt to create motion from such temporal patterns, which is extremely difficult, because of the complex mechanical linkage along the chains forming the multi–body system. To understand, predict and sometimes control multi–body systems, we may want to have mathematical expressions for them. The Newton–Euler, Lagrangian and Featherstone approaches have their advantages and disadvantages. The simulation of collisions and the inclusion of muscle forces or other internal forces are discussed. Also, the possibility to perform a mixed inverse and forward dynamics calculation are dealt with. The use and limitations of these approaches form the conclusion.

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.

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.

Study on kinematics and inverse dynamics of legged mobile manipulator for determining feet-terrain reaction forces and joint torques

2018 ◽  
Vol 233 (9) ◽  
pp. 3117-3136
Author(s):  
Kondalarao Bhavanibhatla ◽  
Dilip Kumar Pratihar
Keyword(s):  
Power Consumption ◽  
Inverse Dynamics ◽  
Kinematic Model ◽  
High Mobility ◽  
General Purpose ◽  
Robotic System ◽  
Mobile Manipulator ◽  
Space Applications ◽  
Joint Torques ◽  
Reaction Forces

Legged mobile manipulator is a robotic system that consists of a serial manipulator rigidly mounted on a multi-legged platform. Its high mobility and dexterity makes this robotic system more suitable to be used in disaster management and space applications, where there will be an uneven and unstructured terrain. However, its high power consumption and low stability under external disturbances are the challenges to be solved. In this paper, an attempt is made to determine the feet-terrain reaction forces and joint actuating torques, which ensures the minimum power consumption. Initially, the kinematic model of the robotic system is developed using general-purpose rigid body analysis. Newton–Euler approach is then utilized to formulate the coupled dynamics of this multi-body system. The developed inverse dynamics model considers the inertial effects of the manipulator and moving legs on the trunk body and stationary legs. However, it has no unique solution due to its high redundancy. Therefore, it has been formulated as an optimization problem in order to minimize the power consumption after satisfying some functional constraints. The performance of the developed approach has been tested on computer simulations. The results show that the developed model can efficiently study the kinematics and dynamics of the legged mobile manipulator and also explain the nature of shifting of center of gravity of the combined robotic system due to the movement of the manipulator links. The developed model is a generalized one and it can be used for carrying out stability analysis and designing suitable controller for the combined robotic system.

Pelvic Rotation Torque During Fast-Pitch Softball Hitting Under Three Ball Height Conditions

2014 ◽  
Vol 30 (4) ◽  
pp. 563-573 ◽  
Author(s):  
Yoichi Iino ◽  
Atsushi Fukushima ◽  
Takeji Kojima
Keyword(s):  
Hip Joint ◽  
Inverse Dynamics ◽  
External Rotation ◽  
Force Plate ◽  
Joint Torque ◽  
Upper Body ◽  
Hip Joints ◽  
Joint Torques ◽  
Pelvic Rotation ◽  
Hip Flexion

The purpose of this study was to investigate the relevance of hip joint angles to the production of the pelvic rotation torque in fast-pitch softball hitting and to examine the effect of ball height on this production. Thirteen advanced female softball players hit stationary balls at three different heights: high, middle, and low. The pelvic rotation torque, defined as the torque acting on the pelvis through the hip joints about the pelvic superior–inferior axis, was determined from the kinematic and force plate data using inverse dynamics. Irrespective of the ball heights, the rear hip extension, rear hip external rotation, front hip adduction, and front hip flexion torques contributed to the production of pelvic rotation torque. Although the contributions of the adduction and external rotation torques at each hip joint were significantly different among the ball heights, the contributions of the front and rear hip joint torques were similar among the three ball heights owing to cancelation of the two torque components. The timings of the peaks of the hip joint torque components were significantly different, suggesting that softball hitters may need to adjust the timings of the torque exertions fairly precisely to rotate the upper body effectively.

scholarly journals Quadrupedal Robots Whole-Body Motion Control Based on Centroidal Momentum Dynamics

2019 ◽  
Vol 9 (7) ◽  
pp. 1335 ◽  
Author(s):  
Mingmin Liu ◽  
Daokui Qu ◽  
Fang Xu ◽  
Fengshan Zou ◽  
Pei Di ◽  
...  
Keyword(s):  
Inverse Dynamics ◽  
Rate Of Change ◽  
Body Motion ◽  
Whole Body ◽  
Quadratic Program ◽  
Control Task ◽  
Joint Torques ◽  
Reaction Forces ◽  
Real Hardware ◽  
Capture Point

In this paper, we demonstrate a method for quadruped dynamic locomotion based oncentroidal momentum control. Our method relies on a quadratic program that solves an optimalcontrol problem to track the reference rate of change of centroidal momentum as closely as possiblewhile satisfying the dynamic, input, and contact constraints of the full quadruped robot dynamics.Given the desired footstep positions, the according reference rate of change of the centroidalmomentum is formulated as a feedback control task derived from the CoM motions of a simplifiedmodel (linear inverted pendulum) based on Capture Point dynamics. The joint accelerations and theGround Reaction Forces(GRFs) outputted from the quadratic program solver are used to calculatethe desired joint torques using an inverse dynamics algorithm. The performance of the proposedmethod is tested in simulation and on real hardware.

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