Control of a tool mounted on a robotic arm

A robotic arm comprising:

• a tool mounted on the robotic arm;
• a plurality of motors configured to manipulate the robotic arm and/or the tool;
• a projector mounted on the tool or on the robotic arm;
• a camera mounted on the tool or on the robotic arm;
• and
• a controller configured to perform an operation of controlling the position of the tool relative to a workpiece, the operation comprising:
• projecting an image onto the workpiece from the projector, wherein the projected image comprises a line;
• detecting the projected image using the camera;
• using the detected image to determine a relative position of the tool with respect to the workpiece;
• and
• providing the determined relative position as an input to a relative position controller, wherein the relative position controller is configured to:
• compare the determined relative position of the tool to a predetermined value, or to a range of predetermined values;
• and
• if the determined relative position of the tool is not equal to the predetermined value, or is not within the range of predetermined values, issue a relative position control signal to a tool position controller, wherein the relative position control signal comprises an instruction to move the tool to a new position in which the relative position of the tool is closer to the predetermined value, or closer to the range of predetermined values;
• or
• if the determined relative position of the tool is equal to the predetermined value, or is within the range of predetermined values, issue a relative position control signal to the tool position controller, wherein the relative position control signal comprises an instruction to maintain the tool in its current relative position,
• wherein the tool position controller is configured to use the relative position control signal to determine a motor control signal, and wherein the tool position controller is configured to issue the motor control signal to the one or more motor controllers.

A computer program comprising instructions which, when executed, cause a robotic arm to execute an operation controlling a position of a tool relative to a workpiece, wherein the tool is mounted on the robotic arm, and wherein the tool position is manipulable by a plurality of motors controlled by one or more motor controllers, the operation, comprising:

• projecting an image onto the workpiece from a projector mounted on the tool or on the robotic arm, wherein the projected image comprises a line;
• detecting the projected image using a camera mounted on the tool or on the robotic arm;
• using the detected image to determine a relative position of the tool with respect to the workpiece;
• and
• providing the determined relative position as an input to a relative position controller, wherein the relative position controller is configured to:
• compare the determined relative position of the tool to a predetermined value, or to a range of predetermined values;
• and
• if the determined relative position of the tool is not equal to the predetermined value, or is not within the range of predetermined values, issue a relative position control signal to a tool position controller, wherein the relative position control signal comprises an instruction to move the tool to a new position in which the relative position of the tool is closer to the predetermined value, or closer to the range of predetermined values;
• or
• if the determined relative position of the tool is equal to the predetermined value, or is within the range of predetermined values, issue a relative position control signal to the tool position controller, wherein the relative position control signal comprises an instruction to maintain the tool in its current relative position,
• wherein the tool position controller is configured to use the relative position control signal to determine a motor control signal, and wherein the tool position controller is configured to issue the motor control signal to the one or more motor controllers.

A method of controlling the position of a tool relative to a workpiece, wherein the tool is mounted on a robotic arm, and wherein the tool position is manipulable by a plurality of motors controlled by one or more motor controllers, the method comprising:

• projecting a image onto the workpiece from a projector, wherein the image comprises a line;
• detecting the image using a camera;
• using the image to determine a first relative position of the tool with respect to the workpiece;
• and
• providing the first relative position as an input to a relative position controller, wherein the relative position controller is configured to:
• compare the first relative position of the tool to a predetermined value or a range of predetermined values;
• and
• upon determining that the first relative position of the tool is not equal to the predetermined value, or is not within the range of predetermined values, issue a first relative position control signal to a tool position controller, wherein the first position control signal comprises an instruction to move the tool to a new position in which the relative position of the tool is closer to the predetermined value, or closer to the range of predetermined values;
• wherein the tool position controller is configured to use the first relative position control signal to determine a first motor control signal, and wherein the tool position controller is configured to issue the first motor control signal to the one or more motor controllers.