Robot arm safety system with runtime adaptable safety limits

1 . A robot system comprising:

a robotic arm connecting a base and a tool flange;

a process controller comprising a processing device configured to control operation of the robotic arm using basic control software and process control software; and

a safety controller comprising a processing device configured to monitor and to control operation of the robotic arm;

wherein the basic control software is associated with safety limits, the safety limits having normal values, the normal values of the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software;

wherein the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the process control software, the process value being different from a normal value for the at least one safety limit;

wherein the process controller is configured to determine whether to change a mode of operation of the robotic arm when an evaluation of one or more values of one or more operational parameters of the robotic arm estimates a violation of a more restrictive one of the process value or the normal value for the at least one safety limit; and

wherein the safety controller is configured to cause the robotic arm to stop operation of the robotic arm when the process controller fails to observe the violation and when the evaluation of the one or more values of the one or more operational parameters results in determining the violation.

2 . The robot system of claim 1 , wherein the safety controller is configured to compare the normal value to the process value to determine the more restrictive one of the process value or the normal value.

3 . The robot system of claim 1 , wherein, when the process controller changes the mode of operation of the robotic arm by stopping operation of the robotic arm, the process controller is configured to leave the robotic arm powered on; and wherein, when the safety controller stops operation of the robotic arm, the safety controller is configured to power-off the robotic arm.

4 . The robot system of claim 1 , wherein the process value comprises a first value minus a first offset and the normal value comprises a second value minus a second offset.

5 . The robot system of claim 4 , wherein the evaluation comprises determining the process value by subtracting the first offset from the first value and determining the normal value by subtracting the second offset from the second value.

6 . The robot system of claim 1 , wherein the process controller is configured to compare the normal value and the process value to determine the more restrictive one of the process value or the normal value.

7 . The robot system of claim 1 , wherein when the process controller changes the mode of operation of the robotic arm, the process controller is configured to put the robotic arm in a reduced operation mode that is based on a reduced normal value among the normal values.

8 . The robot system of claim 1 , wherein the at least one safety limit is associated with the process value when the process control software is uploaded to a memory from which the process controller can execute the basic control software and the process control software.

9 . The robot system of claim 1 , further comprising:

memory to store values for the safety limits.

10 . The robot system of claim 1 , wherein the safety limits comprise one or more of the following: tool center point speed, tool center point force, elbow speed, elbow force, joint speed, joint position, stopping distance, stopping time, power limit, torque limit, or tool direction.

11 . The robot system of claim 1 wherein at least one of the following controllers is configured to perform the evaluation of the one or more operational parameters: the process controller, the safety controller, or a robot joint controller.

12 . The robot system of claim 1 , wherein the evaluation of the one or more values of the one or more operational parameter comprises obtaining the one or more values for the one or more operational parameters, respectively, and comparing the one or more values to at least one of the process value or the normal value for the at least one safety limit.

13 . The robot system of claim 1 , wherein a safety rating of the safety controller is higher than a safety rating of the process controller.

14 . The robot system of claim 1 , wherein the safety controller is configured to provide a confirmation to the process controller, where the confirmation indicates that the safety controller has received the process value for the at least one safety limit.

15 . The robot system of claim 1 , wherein the safety controller is one of at least two independent safety controllers implemented using different hardware in the robot system, where each independent safety controller is configured to cause the robotic arm to stop operation of the robotic arm when the process controller fails to observe the violation and when evaluation of the one or more values of the one or more operational parameters results in determining the violation.

16 . The robot system of claim 1 , further comprising:

a user interface for enabling a user to communicate with the robot system, wherein the user interface comprises means for changing the process value while the robotic arm is in operation.

17 . The robot system of claim 1 , where the one or more values of the one or more operational parameters are based on sensor input.

18 . A method of monitoring a robot system, where the robot system comprises:

(i) a robotic arm comprising joints connecting a base and a tool flange;

(ii) a process controller comprising a processing device configured to operate the robotic arm using at least one of basic control software and process control software, wherein:

(a) the basic control software is associated with safety limits, the safety limits having normal values, the normal values of the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software, and

(b) the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the process control software, the process value being different from a normal value for the at least one safety limit; and

(iii) a safety controller comprising a processing device configured to monitor and to control operation of the robotic arm, wherein the process controller and the safety controller are different hardware; and

wherein the method comprises:

during operation of the robotic robot arm, obtaining one or more values of one or more operational parameters of the robotic arm;

using the process controller, determining whether to change a mode of operation of the robotic arm when an evaluation of the one or more operational parameters estimates a violation of a more restrictive one of the process value or the normal value for the at least one safety limit; and

using the safety controller, causing the robotic arm to stop operation of the robotic arm when the process controller fails to observe the violation and when the evaluation of the one or more operational parameters results in determining the violation.

19 . The method of claim 18 , further comprising:

comparing the normal value and the process value to determine the more restrictive one.

20 . The method of claim 18 , the wherein at least part of the evaluation is performed on at least one of the process controller or the safety controller.

21 . The method of claim 20 , wherein the evaluation comprises comparing the one or more operational parameters with the more restrictive one of the process value or the normal value.

22 . The method of claim 18 , further comprising:

obtaining the one or more values of the one or more operational parameters using one or more joint controllers.

23 . The method of claim 18 , further comprising:

obtaining the one or more values of the one or more operational parameters based on sensor input.

24 . The method of claim 18 , wherein at least part of the evaluation is performed using one or more joint controllers.

25 . The method of claim 18 , further comprising: receiving a signal at at least one of the process controller or the safety controller, the signal comprising a result of the evaluation, and based on the signal, at least one of the process controller or the safety controller determines if a change of the mode of operation of the robotic arm is necessary.

26 . The method of claim 18 , further comprising:

adjusting the process value for at least one safety limit while the robotic arm is operational.

27 . The method of claim 18 , wherein the process control software is obtained from an external data processing unit.

28 . The method of claim 18 , wherein, when the process controller changes the mode of operation of the robotic arm by stopping operation of the robotic arm, the process controller leaves the robotic arm powered on; and

wherein, when the safety controller stops operation of the robotic arm, the safety controller powers-off the robotic arm.

29 . The method of claim 18 , wherein the process value comprises a first value minus a first offset and the normal value comprises a second value minus a second offset.

30 . The method of claim 29 , wherein the evaluation comprises determining the process value by subtracting the first offset from the first value and determining the normal value by subtracting the second offset from the second value.

31 . A robot system comprising:

a robotic arm connecting a base and a tool flange;

a process controller comprising a processing device configured to control operation of the robotic arm using basic control software and process control software; and

a safety controller comprising a processing device configured to monitor and to evaluate operation of the robotic arm;

wherein the basic control software is associated with safety limits, the safety limits having normal values, the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software;

wherein the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value that is different from a normal value for the at least one safety limit;

wherein the process value is changeable while the robot system is in run-time mode;

wherein the process controller is configured to cause the robotic arm to enter a violation stop mode when an evaluation of the one or more operational parameters results in determining a violation of a more restrictive one of the process value minus an offset or the normal value minus an offset for the at least one safety limit; and

wherein the safety controller is configured to cause the robotic arm to enter the violation stop mode when an evaluation of the one or more operational parameters results in determining a violation of a more restrictive one of the process value or the normal value for the at least one safety limit.

32 . A robot system comprising:

a robotic arm connecting a base and a tool flange;

a process controller comprising a processing device configured to control operation of the robotic arm using basic control software and process control software; and

a safety controller comprising a processing device configured to monitor and to evaluate operation of the robotic arm;

wherein the basic control software is associated with safety limits, the safety limits having normal values, the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software;

wherein the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value that is different from a normal value for the at least one safety limit;

wherein the process value is changeable while the robot system is in run-time mode;

wherein the safety controller is configured to cause the robotic arm to enter a violation stop mode when an evaluation of the one or more operational parameters determines a violation of a more restrictive one of the process value or the normal value for the at least one safety limit; and

wherein the evaluation comprises subtracting an offset from the process value and subtracting an offset from the normal value before determining the violation of the more restrictive one of the process value or the normal value.

33 . A robot system comprising:

a robotic arm connecting a base and a tool flange;

a process controller comprising a processing device configured to control operation of the robotic arm using basic control software and process control software; and

a safety controller comprising a processing device configured to monitor and to control operation of the robotic arm;

wherein the basic control software is associated with safety limits, the safety limits having normal values, the normal values of the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software;

wherein the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the process control software, the process value being different from a normal value for the at least one safety limit;

wherein the process controller is configured to determine whether to change to a mode of operation of the robotic arm that does not include power off when an evaluation of one or more values of one or more operational parameters of the robotic arm estimates a violation of a more restrictive one of the process value or the normal value for the at least one safety limit; and

wherein the safety controller is configured to cause the robotic arm to stop operation of the robotic arm when the evaluation of the one or more values of the one or more operational parameters results in determining the violation.

34 . A robot system comprising:

a robotic arm connecting a base and a tool flange;

a process controller comprising a processing device configured to control operation of the robotic arm using basic control software and process control software; and

a safety controller comprising a processing device configured to monitor and to control operation of the robotic arm;

wherein the basic control software is associated with safety limits, the safety limits having normal values, the normal values of the safety limits for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the basic control software;

wherein the process control software is associated with at least one safety limit among the safety limits, the at least one safety limit having a process value for limiting operation of the robotic arm when the robotic arm is controlled by the process controller using the process control software, the process value being different from a normal value for the at least one safety limit;

wherein the process controller is configured to determine whether to change operation of the robotic arm to a protective stop mode when an evaluation of one or more values of one or more operational parameters of the robotic arm estimates a violation of a more restrictive one of the process value or the normal value for the at least one safety limit; and

wherein the safety controller is configured to cause the robotic arm to stop operation of the robotic arm when the evaluation of the one or more values of the one or more operational parameters results in determining the violation.