Estimation or control of contact force in actuators using pressure
Methods, systems, and apparatuses for combining pressure measurement with a dynamic system model to estimate the air mass within an actuator, and then estimate the applied contact force which may be based on a quasi-static deformation model.
1. A system comprising:
an actuator fluidically coupled with a pressure-changing device, the pressure-changing device being configured to control a pressure of fluid in the actuator; and
a computer readable storage medium storing computer executable instructions that when executed by a device cause the device to:
receive a pressure measurement of a fluid in the actuator;
determine, based on the pressure measurement, a mass of the fluid in the actuator, wherein the determine of the mass comprises using a model associated with one or more components of a haptic assembly;
determine, based on the mass of the fluid, a height of the actuator;
determine a contact force based on the height of the actuator and the pressure measurement of the fluid;
transmit the contact force;
determine, based on the contact force, a modified pressure to create a second contact force associated with the one or more components of the haptic assembly; and
adjust the pressure of the actuator to the modified pressure.
2. The system of claim 1 , wherein the contact force is transmitted to an artificial reality device.
3. The system of claim 1 , wherein the contact force is transmitted to a display.
4. The system of claim 1 , wherein the determine of the contact force is further based on a piston area of the actuator.
5. A system comprising:
an actuator fluidically coupled with a pressure-changing device, the pressure-changing device being configured to control a pressure of fluid in the actuator; and
an apparatus comprising:
one or more first processors; and
at least one first non-transitory memory coupled with the one or more first processors, the at least one first non-transitory memory storing executable instructions that when executed by the one or more first processors cause the apparatus to:
determine a contact force to apply using the actuator;
determine, based on the contact force, modified pressure to create the contact force associated with the one or more components of a haptic assembly, wherein the determine the modified pressure is based on using a mass flow rate model associated with the one or more components of the haptic assembly; and
send a message to the one or more components of the haptic assembly, wherein the message comprises instructions to change an actuator pressure to the modified pressure; and
the haptic assembly comprising:
one or more second processors; and
at least one second non-transitory memory coupled with the one or more second processors, the at least one second non-transitory memory storing executable instructions that when executed by the one or more second processors cause the haptic assembly to:
receive the message to change the actuator pressure to the modified pressure; and
adjust the actuator pressure to the modified pressure.
6. The system of claim 5 , wherein the apparatus is a component of an artificial reality device.
7. The system of claim 5 , wherein the determined contact force is transmitted to a display or an artificial reality device.
8. The system of claim 5 , wherein the fluid comprises air.
9. The system of claim 5 , wherein the determine the contact force is based on a height of the actuator or an actuator stiffness.
10. A method comprising:
receiving a pressure measurement of a fluid in an actuator;
determining, based on the pressure measurement, a mass of the fluid in the actuator;
determining a height of the actuator based on the mass of the fluid and the pressure measurement of the fluid;
determining a contact force based on the height of the actuator and the pressure measurement of the fluid; and
transmitting the contact force;
determining, based on the contact force, a modified pressure to create a second contact force associated with one or more components of a haptic assembly; and
adjusting a pressure of the actuator to the modified pressure.
11. The method of claim 10 , wherein the determining the mass comprises using a mass flow rate model associated with the one or more components of the haptic assembly.
12. The method of claim 10 , wherein the determining the contact force comprises using a deformation model.
13. The method of claim 10 , wherein the contact force is transmitted to a display.
14. The method of claim 10 , wherein the contact force is transmitted to an artificial reality device.
15. The method of claim 10 , wherein the actuator comprises a pneumatic actuator.
16. The method of claim 10 , wherein the actuator is part of the haptic assembly.
17. The method of claim 10 , wherein:
the determining the contact force is further based on an actuator stiffness that is based on a change of pressure.
18. The method of claim 10 , wherein the determining the contact force is further based on a piston area of the actuator.
19. The method of claim 10 , wherein the pressure measurement is based on a comparison of a first pressure from a first pressure sensor and a second pressure of a second pressure sensor.
20. A device comprising:
one or more processors; and
at least one non-transitory memory coupled with the one or more processors, the at least one non-transitory memory storing executable instructions that when executed by the one or more processors cause the device to:
determine a contact force to apply using an actuator;
determine, based on the contact force, modified pressure to create a second contact force associated with one or more components of a haptic assembly, wherein the determine the modified pressure is based on using a mass flow rate model associated with the one or more components of the haptic assembly;
generate a message that comprises instructions to change actuator pressure to the modified pressure; and
adjust, by the haptic assembly, the actuator pressure to the modified pressure.