Optimal Posture and Supporting Hand Force Prediction for Common Automotive Assembly One-Handed Tasks

Abstract

People often complete tasks using one hand for the task and one hand for support. These one-handed support tasks can be found in many different types of jobs, such as automotive assembly jobs. Optimization-based posture prediction has proven to be a valid tool in predicting the postures necessary to complete the tasks, but the related external support forces have been prescribed and not predicted. This paper presents a method in which the optimal posture and related supporting hand forces can be predicted simultaneously using optimization and stability analysis techniques. Postures are evaluated using a physics-based human performance measure (HPM) while external forces are assessed using stability analysis. The physics-based performance measures are based on joint torque. Stability is analyzed using criteria based on a 3D zero moment point (ZMP). The human model used in the prediction contains 56 degrees of freedom and is based on a 50th percentile female in stature. Tasks based on common automotive assembly one-handed tasks found in literature are considered as examples to test the proposed method. Overall, the predicted supporting hand forces have good correlation with experimentally measured forces.

Modeling Robot Geometries Like Molecules, Application to Fast Multicontact Posture Planning for Humanoids

“…It becomes interesting to test them separately, since many similar posture optimization methods in literature rely on minimizing joint torques [7], [15]. Enabling contact force terms produce less optimal solutions ( Figure.7), since they are in conflict with joint torques.…”

“…In these tasks, the inherent redundancy in the system is solved by optimizing the overall joint torques while in normal IK methods, a desired position and orientation is considered for the pelvis, torso or the Center of Mass (CoM). The task of optimizing postures is well addressed in the literature, for example in matching a model with recorded human data in OpenSim [6] or analyzing multicontact human postures in car assembly lines [7]. In static optimal postures, the equations of motion ensure stability of the humanoid while in normal IK methods, the Zero Moment Point (ZMP) or CoM is forced to lie within the support polygon [5].…”

All’s not Fair in CAD: An Investigation of Equity of Contributions to Collaborative Cloud-based Design Projects

“…guring out when is support taken and when not; which surface and where on it meaningful supports can be obtained and estimating the support reaction force (SRF) and their eect on the posture. The problem of estimating the supportedpostures and the reaction forces using DHMs has been studied by [4], [10], [9]. The work by [4] is based on choosing a supported posture and then trying out dierent SRFs at support-contact to arrive at an acceptable force.…”

Computing Similarities of Images: A Point Cloud-based Approach

“…The work by [4] is based on choosing a supported posture and then trying out dierent SRFs at support-contact to arrive at an acceptable force. The works by [10] and [9] describe the technique of computing supported-posture along with SRFs by considering the SRF as an optimisation variable when the location of support-contact is given. [2], [6] and [16] performed empirical studies and developed regression models to predict when and how the human will take support for a given task and anthropometry.…”