Extending FABRIK with Obstacle Avoidance for Solving the Inverse Kinematics Problem

Abstract

Inverse kinematics (IK) has been extensively applied in the areas of robotics, computer animation, ergonomics, and gaming. Typically, IK determines the joint configurations of a robot model and achieves a desired end-effector position in robotics. Since forward and backward teaching inverse kinematics (FABRIK) is a forward and backward iterative method that finds updated joint positions by locating a point on a line instead of using angle rotations or matrices, it has the advantages of fast convergence, low computational cost, and visualizing realistic poses. However, the manipulators usually work in a complex environment. So, the kinematic chains are easy to produce the interference with their surrounding scenarios. To resolve the above mentioned problem, a two-step obstacle avoidance technology is proposed to extend the basic FABRIK in this study. The first step is a heuristic method that locates the updated linkage bar, the root joint, and the target position in a line, so that the interference can be eliminated in most cases. In the second step, multiple random rotation strategies are adopted to eliminate the interference that has not been eliminated in the first step. Experimental results have shown that the extending FABRIK has the obstacle avoidance ability.

Forward and Backward Reaching Inverse Kinematics (FABRIK) solver for DHM: A pilot study

“…Recently, FABRIK has been extended for application in robotics for both fixed position and mobile multi-joint robots (M. Santos et al, 2021;P. C. Santos et al, 2020;Tao et al, 2021;Tenneti & Sarkar, 2019).…”

“…While FABRIK is correspondingly not guaranteed to provide a feasible or plausible solution, current applications of the solver in design and game development contexts suggest that it can provide good solutions in the vast majority of human motion prediction problems (Aristidou et al, 2016;Aristidou & Lasenby, 2011;M. Santos et al, 2021;Tao et al, 2021).…”

“…Several modifications and variations of the FABRIK solver have been developed that allow for multi-chain/branching systems, non-fixed root nodes, whole system repositioning, handling unsolvable targets, and obstacles (Aristidou et al, 2016;P. C. Santos et al, 2020;Tao et al, 2021). In the current project we used only the original algorithm along with a hinge constraint applied to the elbow as discussed in Aristidou and Lasenby (2011).…”

Proceedings of the 7th International Digital Human Modeling Symposium, Aug. 29-31, 2022, Iowa City, Iowa, USA

“…While FABRIK is correspondingly not guaranteed to provide a feasible or plausible solution, current applications of the solver in design and game development contexts suggest that it can provide good solutions in the vast majority of human motion prediction problems (Aristidou et al, 2016;M. Santos et al, 2021;Tao et al, 2021). The FABRIK solver works in joint position space and is applied hierarchically to each joint and iteratively until a solution is identified.…”

“…Several modifications and variations of the FABRIK solver have been developed that allow for multi-chain/branching systems, non-fixed root nodes, whole system repositioning, handling unsolvable targets, and obstacles (Aristidou et al, 2016;P. C. Santos et al, 2020;Tao et al, 2021). In the current project we used only the original algorithm along with a hinge constraint applied to the elbow as discussed in .…”