Dynamic mass estimation methods for an integrated mobile manipulator robot
A method of estimating one or more mass characteristics of a payload manipulated by a robot includes moving the payload using the robot, determining one or more accelerations of the payload while the payload is in motion, sensing, using one or more sensors of the robot, a wrench applied to the payload while the payload is in motion, and estimating the one or more mass characteristics of the payload based, at least in part, on the determined accelerations and the sensed wrench.
1. A method of estimating one or more mass characteristics of a payload manipulated by a robot, the method comprising:
moving the payload using the robot, wherein the payload is grasped by an end effector of the robot;
determining one or more accelerations of the payload while the payload is in motion;
sensing, using one or more sensors of the robot, a wrench applied to the payload while the payload is in motion;
estimating the one or more mass characteristics of the payload based, at least in part, on the determined accelerations and the sensed wrench; and
planning, while the payload remains grasped by the end effector of the robot, a trajectory based, at least in part, on the estimated one or more mass characteristics of the payload.
2. The method of claim 1 , wherein:
determining the one or more accelerations of the payload while the payload is in motion comprises determining the one or more accelerations of the payload while the payload is moved through an excitation routine; and
sensing the wrench applied to the payload while the payload is in motion comprises sensing the wrench applied to the payload while the payload is moved through the excitation routine.
3. The method of claim 1 , wherein determining the one or more accelerations of the payload comprises determining the one or more accelerations of the payload based, at least in part, on one or more motions of the robot.
4. The method of claim 3 , wherein determining the one or more accelerations of the payload based, at least in part, on the one or more motions of the robot comprises:
determining one or more joint motions of a robotic arm of the robot; and
determining one or more accelerations of the robotic arm based, at least in part, on the one or more joint motions and a kinematic model of the robotic arm.
5. The method of claim 3 , wherein determining the one or more accelerations of the payload based, at least in part, on the one or more motions of the robot comprises determining the one or more accelerations of the payload based, at least in part, on the one or more motions of a robotic arm of the robot and motion of a mobile base of the robot, wherein the robotic arm is operatively coupled to the mobile base.
6. The method of claim 1 , wherein sensing the wrench comprises sensing the wrench applied to the payload by an end effector of a robotic arm of the robot.
7. The method of claim 1 , wherein sensing the wrench comprises sensing a wrench associated with a wrist of a robotic arm of the robot.
8. The method of claim 7 , wherein sensing the wrench associated with the wrist of the robotic arm comprises sensing the wrench using a 6-axis force/torque sensor.
9. The method of claim 1 , wherein estimating the one or more mass characteristics of the payload comprises estimating one or more of a mass of the payload, a center of mass of the payload, and one or more moments of inertia of the payload.
10. The method of claim 1 , wherein estimating the one or more mass characteristics of the payload comprises estimating at least ten mass characteristics, wherein the at least ten mass characteristics comprise one mass parameter, three center of mass parameters, and six moment of inertia parameters.
11. The method of claim 1 , wherein estimating the one or more mass characteristics of the payload comprises estimating the one or more mass characteristics of the payload within a time period of less than 0.5 seconds.
12. The method of claim 1 , wherein estimating the one or more mass characteristics of the payload comprises estimating the one or more mass characteristics of the payload based, at least in part, on one or more priors.
13. The method of claim 12 , wherein estimating the one or more mass characteristics of the payload based, at least in part, on the one or more priors comprises estimating the one or more mass characteristics of the payload based, at least in part, on one or more physical dimensions of the payload.
14. A method of planning a trajectory, the method comprising:
estimating one or more mass characteristics of a payload according to the method of claim 1 ;
computing inverse dynamics of the payload based, at least in part, on the estimated one or more mass characteristics of the payload; and
planning the trajectory based, at least in part, on the computed inverse dynamics.
15. The method of claim 14 , wherein computing the inverse dynamics comprises computing one or more torques to be applied at one or more joints of a robotic arm of the robot.
16. The method of claim 14 , wherein planning the trajectory comprises optimizing the trajectory based, at least in part, on the estimated one or more mass characteristics of the payload.
17. The method of claim 16 , wherein optimizing the trajectory comprises optimizing one or more of a speed of the payload and an acceleration of the payload.
18. The method of claim 16 , wherein optimizing the trajectory includes minimizing the wrench required to displace the payload.
19. The method of claim 1 , further comprising controlling an operation of the robot based, at least in part, on the trajectory.
20. A robot comprising:
a robotic arm;
an end effector operatively coupled to a distal portion of the robotic arm;
one or more sensors; and
a controller configured to:
determine one or more accelerations of a payload grasped by the end effector of the robot while the payload is in motion;
determine a wrench applied to the payload while the payload is in motion based on signals from the one or more sensors;
estimate one or more mass characteristics of the payload based, at least in part, on the determined accelerations and the determined wrench; and
plan, while the payload remains grasped by the end effector, a trajectory based, at least in part, on the estimated one or more mass characteristics of the payload.
21. The robot of claim 20 , wherein:
the controller is configured to determine the one or more accelerations of the payload while the payload is moved through an excitation routine; and
the controller is configured to determine the wrench applied to the payload while the payload is moved through the excitation routine.
22. The robot of claim 20 , further comprising a mobile base, wherein the robotic arm is operatively coupled to the mobile base.
23. The robot of claim 20 , wherein the controller is further configured to:
determine one or more joint motions of the robotic arm; and
determine one or more accelerations of the robotic arm based, at least in part, on the one or more joint motions and a kinematic model of the robotic arm.
24. The robot of claim 20 , wherein the controller is configured to determine a wrench applied to the payload by the end effector.
25. The robot of claim 20 , wherein the one or more sensors are configured to sense a wrench associated with a wrist of the robotic arm.
26. The robot of claim 20 , wherein the one or more sensors comprise a 6-axis force/torque sensor.
27. The robot of claim 20 , wherein the controller is configured to estimate one or more of a mass of the payload, a center of mass of the payload, and one or more moments of inertia of the payload.
28. The robot of claim 20 , wherein the controller is configured to estimate at least ten mass characteristics, wherein the at least ten mass characteristics comprise one mass parameter, three center of mass parameters, and six moment of inertia parameters.
29. The robot of claim 20 , wherein the controller is further configured to control an operation of the robot based, at least in part, on the trajectory.