Method of controlling a robot through a singularity

A method of controlling a robot (32) having a plurality of arms rotatable about a plurality of axes defining a plurality of angles therebetween and supporting a tool (49) having a tool point (TCP) for relative movement of the tool (49) along a path (33) having a starting point (44) and an ending point (46) defined in Cartesian coordinates, wherein the robot (32) has at least one of a first configuration set having an up configuration and a down configuration, a second configuration set having a flip configuration and a no-flip configuration, and a third configuration set having a front configuration and a back configuration, and wherein the robot (32) approaches a singularity associated with the configuration set along the path (33) while moving about the plurality of axes, said method comprising the steps of:

• selecting the up configuration, the no-flip configuration, and the front configuration from the first, second, and third sets to position the TCP at the starting point (44) with the angles of the arms in an initial configuration;
• selecting the up configuration, the no-flip configuration, and the back configuration from the sets to position the TCP at the ending point (46) with the angles of the arms in a final configuration;
• rotating the arms about the axes by changing the angles therebetween to move the TCP from the starting point (44) along the path (33) while maintaining the initial configuration;
• approaching the singularity which occurs between a first point (48) and a second point (50) along the path (33);
• selecting one of the axes in the initial configuration in response to reaching the first point (48);
• interpolating the angle for the selected axis from the first point (48) to the second point (50) in a predetermined number of steps (52) between the first point (48) and the second point (50);
• determining the angles about the remaining axes in relationship to the aforesaid interpolation at each of the steps (52) to position the arms in the final configuration when the TCP reaches the second point (50) in response to determining the angles;
• and
• rotating the arms about the axes by changing the angles therebetween to move the TCP along the path (33) to the ending point (46) while maintaining the final configuration.

A method of controlling a robot (32) having a plurality of arms rotatable about a plurality of axes defining a plurality of angles therebetween and supporting a tool (49) having a tool point (TCP) for relative movement of the tool (49) along a path (33) having a starting point (44) and an ending point (46) defined in Cartesian coordinates, wherein the robot (32) has at least one of a first configuration set having an up configuration and a down configuration, a second configuration set having a flip configuration and a no-flip configuration, and a third configuration set having a front configuration and a back configuration, and wherein the robot (32) approaches a singularity associated with the configuration set along the path (33) while moving about the plurality of axes, said method comprising the steps of:

• selecting the up configuration, the no-flip configuration, and the front configuration from the first, second, and third sets to position the TCP at the starting point (44) with the angles of the arms in an initial configuration;
• selecting the down configuration, the no-flip configuration, and the front configuration from the sets to position the TCP at the ending point (46) with the angles of the arms in a final configuration;
• rotating the arms about the axes by changing the angles therebetween to move the TCP from the starting point (44) along the path (33) while maintaining the initial configuration;
• approaching the singularity which occurs between a first point (48) and a second point (50) along the path (33);
• selecting one of the axes in the initial configuration in response to reaching the first point (48);
• interpolating the angle for the selected axis from the first point (48) to the second point (50) in a predetermined number of steps (52) between the first point (48) and the second point (50);
• determining the angles about the remaining axes in relationship to the aforesaid interpolation at each of the steps (52) to position the arms in the final configuration when the TCP reaches the second point (50) in response to determining the angles;
• and
• rotating the arms about the axes by changing the angles therebetween to move the TCP along the path (33) to the ending point (46) while maintaining the final configuration.

A method of controlling a robot (32) having a plurality of arms rotatable about a plurality of axes defining a plurality of angles therebetween and supporting a tool (49) having a tool point (TCP) for relative movement of the tool (49) along a path (33) having a starting point (44) and an ending point (46) defined in Cartesian coordinates, wherein the robot (32) has at least one of a first configuration set having an up configuration and a down configuration, a second configuration set having a flip configuration and a no-flip configuration, and a third configuration set having a front configuration and a back configuration, and wherein the robot (32) approaches a singularity associated with the configuration set along the path (33) while moving about the plurality of axes, said method comprising the steps of:

• selecting the configuration of at least one of the first, second, and third sets to position the TCP at the starting point (44) with the angles of the arms in an initial configuration;
• selecting the other configuration of at least one of the sets to position the TCP at the ending point (46) with the angles of the arms in a final configuration;
• rotating the arms about the axes by changing the angles therebetween to move the TCP from the starting point (44) along the path (33) while maintaining the initial configuration;
• approaching the singularity which occurs between a first point (48) and a second point (50) along the path (33);
• selecting one of the axes in the initial configuration in response to reaching the first point (48);
• interpolating the angle for the selected axis from the first point (48) to the second point (50) in a predetermined number of steps (52) between the first point (48) and the second point (50);
• determining the angles about the remaining axes in relationship to the aforesaid interpolation at each of the steps (52) to position the arms in the final configuration when the TCP reaches the second point (50) in response to determining the angles;
• and
• rotating the arms about the axes by changing the angles therebetween to move the TCP along the path (33) to the ending point (46) while maintaining the final configuration.

A method of controlling a robot (32) having a plurality of arms rotatable about a plurality of axes defining a plurality of angles therebetween and supporting a tool (49) having a tool point (TCP) for relative movement of the tool (49) along a path (33) having a starting point (44) and an ending point (46) defined in Cartesian coordinates, wherein the robot (32) has at least one of a first configuration set having an up configuration and a down configuration, a second configuration set having a flip configuration and a no-flip configuration, and a third configuration set having a front configuration and a back configuration, and wherein the robot (32) approaches a singularity associated with the configuration set along the path (33) while moving about the plurality of axes, said method comprising the steps of:

• selecting the configuration of at least one of the first, second, and third sets to position the TCP at the starting point (44) with the angles of the arms in an initial configuration;
• selecting the other configuration of at least one of the sets to position the TCP at the ending point (46) with the angles of the arms in a final configuration;
• rotating the arms about the axes by changing the angles therebetween to move the TCP from the starting point (44) along the path (33) while maintaining the initial configuration;
• approaching the singularity which occurs between a first point (48) and a second point (50) along the path (33);
• determining the angles about the axes to move the TCP between the first point (48) and the second point (50) and through the singularity;
• and
• rotating the arms about the axes by changing the angles therebetween to move the TCP along the path (33) while maintaining the final configuration to the ending point (46).