Method of controlling manipulator of industrial robot, control system and industrial robot

A control system for controlling a manipulator of an industrial robot having a plurality of joints, the control system comprising at least one data processing device and at least one memory having a computer program stored thereon, the computer program including program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform the steps of:

• providing a candidate trajectory for the manipulator;
• determining at least one position dependent load value representative of at least one position dependent load acting on the manipulator for the candidate trajectory;
• modifying the candidate trajectory based on the at least one position dependent load value to provide a modified trajectory;
• and
• commanding the manipulator to execute the modified trajectory,
• wherein the computer program, when executed by the at least one data processing device, causes the at least one data processing device to further perform the steps of:
• providing a model describing static and dynamic properties of the manipulator, the model having a position dependent load term;
• determining the at least one position dependent load value for the candidate trajectory based on the position dependent load term;
• determining a load constraint of a load parameter for a mechanical component of the manipulator based on the at least one position dependent load value;
• and
• determining the modified trajectory for the manipulator by solving an optimization problem having an objective function and the load constraint;
• and
• wherein the load constraint is determined as a relatively low load constraint value when a position dependent load value of the position dependent load term is below a position dependent load threshold, and determined as a relatively high load constraint value when the position dependent load value is above the position dependent load threshold.

An industrial robot comprising a manipulator and a control system for controlling the manipulator of the industrial robot having a plurality of joints, the control system comprising at least one data processing device and at least one memory having a computer program stored thereon, the computer program including program code which, when executed by the at least one data processing device, causes the at least one data processing device to perform the steps of:

• providing a candidate trajectory for the manipulator;
• determining at least one position dependent load value representative of at least one position dependent load acting on the manipulator for the candidate trajectory;
• modifying the candidate trajectory based on the at least one position dependent load value to provide a modified trajectory;
• and
• commanding the manipulator to execute the modified trajectory,
• wherein the computer program, when executed by the at least one data processing device, causes the at least one data processing device to further perform the steps of:
• providing a model describing static and dynamic properties of the manipulator, the model having a position dependent load term;
• determining the at least one position dependent load value for the candidate trajectory based on the position dependent load term;
• determining a load constraint of a load parameter for a mechanical component of the manipulator based on the at least one position dependent load value;
• and
• determining the modified trajectory for the manipulator by solving an optimization problem having an objective function and the load constraint;
• and
• wherein the load constraint is determined as a relatively low load constraint value when a position dependent load value of the position dependent load term is below a position dependent load threshold, and determined as a relatively high load constraint value when the position dependent load value is above the position dependent load threshold.