Method and apparatus for controlling robot arms using elastic distortion simulations

An apparatus of solving the inverse kinematics problem of a kinematic chain with multiple links and joints, comprising a computer running a computer program that:

• receives as inputs a set of constraints on configurations of the links and joints of the kinematic chain;
• simulates that the links and joints of the kinematic chain can be distorted so that the configurations of the links and joints can deviate from the constraints;
• defines a distortion measurement function which quantifies distortions as a function of deviations of the configurations of the links and joints from the constraints;
• executes an algorithm that comprises of distorting the simulated kinematic chain to put an end of the kinematic chain in a target position and/or orientation, calculating distortions using the distortion measurement function, and iteratively adjusting the configurations of the links and joints to reduce the distortions while keeping the end of the kinematic chain in the target position and/or orientation until the total distortion of the kinematic chain is zero or smaller than a predetermined threshold, or a maximum number of iterations is reached;
• and
• returns the configurations of the links and joints with total distortion being zero or smaller than the predetermined threshold, if found, as an inverse kinematics solution for the kinematic chain.