Minimum ratio-locked profile times for robot trajectories

A graphical representation of admissible profile times for robot trajectories is presented from a kinematic perspective. Profile times are defined to be the acceleration time, slew time, and deceleration time for robot end effector motions. Given initial and final robot end effector locations, identical profile times are computed for all the joints in the manipulator, where each joint has different acceleration and velocity limits. Ratio-locked profile times occur when the robot motion is joint-coordinated, with all of the joints moving in a proportional manner relative to each other. A closed-form solution to compute the minimum ratio-locked profile times for robot trajectories is presented for the case when the acceleration limit for each joint is equal to its deceleration limit. The algorithm is implemented in the HAL robot control system at HP Labs. for controlling robots in a manufacturing environment