Practical implementation of time-efficient trajectory planning for two cooperative industrial robot arms

A practical approach to time-efficient trajectory planning for two cooperative industrial robots with free final configurations is presented. A time-efficient trajectory planning problem is then formulated which uses time-efficient joint acceleration profiles and is subject to limits on joint positions, velocities, accelerations and jerks. The formula is further simplified by suitably choosing the time intervals of the profile. The optimization problem is solved using a nonlinear optimization method, Sequential Quadratic Programming (SQP). The computation problem arising thereby is successfully dealt with. The proposed method is applied to an environment containing two RTX SCARA type robot arms where their final configurations are relatively given with respect to each other, e.g., in a tool/workpiece operation, and are free with respect to the world frame. The problem is solved in almost real-time. For each robot arm, at least one of the resulting joint trajectories reaches its limit velocity. These joint trajectories are used as reference inputs to a robot control system for the two RTX arms realised on a transputer network. Experiments demonstrating feasibility of this method are conducted.