Mitigating sensor noise in legged robots
An example implementation involves receiving measurements from an inertial sensor coupled to the robot and detecting an occurrence of a foot of the legged robot making contact with a surface. The implementation also involves reducing a gain value of an amplifier from a nominal value to a reduced value upon detecting the occurrence. The amplifier receives the measurements from the inertial sensor and provides a modulated output based on the gain value. The implementation further involves increasing the gain value from the reduced value to the nominal value over a predetermined duration of time after detecting the occurrence. The gain value is increased according to a profile indicative of a manner in which to increase the gain value of the predetermined duration of time. The implementation also involves controlling at least one actuator of the legged robot based on the modulated output during the predetermined duration of time.
1 . A method comprising:
receiving, as an input to an analog electronic amplifier of a legged robot, a sensor output signal from a sensor of the legged robot;
determining, by a control system of the legged robot, that the sensor output signal comprises a signal fluctuation indicative of a vibration arising from a foot of the legged robot contacting a surface;
determining, by the control system, a gain signal profile for the analog electronic amplifier based on the sensor output signal and one or more characteristics of a set of sensor measurement data;
controlling, by the control system, a gain value of the analog electronic amplifier according to the gain signal profile to suppress the signal fluctuation in the sensor output signal; and
controlling, by the control system, an actuator of the legged robot based on an output of the analog electronic amplifier.
2 . The method of claim 1 , further comprising reducing, by the control system, the gain value of the analog electronic amplifier from a nominal gain value to a reduced gain value over a period of time indicated by the gain signal profile.
3 . The method of claim 2 , further comprising increasing, by the control system, the gain value of the analog electronic amplifier from the reduced gain value to the nominal gain value based on detecting an attenuation of the signal fluctuation.
4 . The method of claim 1 , further comprising determining, by the control system, the gain signal profile further based on a gait of the legged robot.
5 . The method of claim 1 , further comprising determining, by the control system, the gain signal profile based on selecting the gain signal profile from two or more gain signal profiles, wherein a first gain signal profile of the two or more gain signal profiles is associated with an exponential change in the gain value over time, and wherein a second gain signal profile of the two or more gain signal profiles is associated with a linear change in the gain value over time.
6 . The method of claim 1 , further comprising determining, by the control system, the gain signal profile further based on detecting an attenuation of the signal fluctuation.
7 . The method of claim 1 , wherein the sensor is an inertial sensor.
8 . The method of claim 1 , further comprising controlling, by the actuator, the foot of the legged robot.
9 . The method of claim 1 , wherein the analog electronic amplifier is configured to adjust a power of the sensor output signal, wherein an amount of adjustment of the power is based on one or more parameters including the gain value of the analog electronic amplifier.
10 . The method of claim 1 , wherein the control system determines the gain signal profile using machine learning.
11 . The method of claim 1 , wherein the set of sensor measurement data comprises a set of previously-recorded measurements from one or more sensors.
12 . A legged robot comprising:
a sensor configured to generate a sensor output signal;
an analog electronic amplifier having an input configured to receive the sensor output signal;
an actuator; and
a control system configured to determine that the sensor output signal comprises a signal fluctuation indicative of a vibration arising from a foot of the legged robot contacting a surface, and to determine a gain signal profile for the analog electronic amplifier based on the sensor output signal and one or more characteristics of a set of sensor measurement data, wherein the control system is further configured to control a gain value of the analog electronic amplifier according to the gain signal profile to suppress the signal fluctuation in the sensor output signal and to control the actuator based on an output of the analog electronic amplifier.
13 . The legged robot of claim 12 , wherein the control system is further configured to reduce the gain value of the analog electronic amplifier from a nominal gain value to a reduced gain value over a period of time indicated by the gain signal profile.
14 . The legged robot of claim 13 , wherein the control system is further configured to increase the gain value of the analog electronic amplifier from the reduced gain value to the nominal gain value based on detecting an attenuation of the signal fluctuation.
15 . The legged robot of claim 12 , wherein the control system is further configured to determine the gain signal profile based on a gait of the legged robot.
16 . The legged robot of claim 12 , wherein the control system is further configured to select the gain signal profile from two or more gain signal profiles, wherein a first gain signal profile of the two or more gain signal profiles is associated with an exponential change in the gain value over time, and wherein a second gain signal profile of the two or more gain signal profiles is associated with a linear change in the gain value over time.
17 . The legged robot of claim 12 , wherein the control system is further configured to determine the gain signal profile based on detecting an attenuation of the signal fluctuation.
18 . The legged robot of claim 12 , wherein the sensor is an inertial sensor.
19 . The legged robot of claim 12 , wherein the actuator is configured to control the foot.
20 . The legged robot of claim 12 , wherein the analog electronic amplifier is configured to adjust a power of the sensor output signal, wherein an amount of adjustment of the power is based on one or more parameters including the gain value of the analog electronic amplifier.
21 . The legged robot of claim 12 , wherein the control system is configured to determine the gain signal profile using machine learning.
22 . The legged robot of claim 12 , wherein the set of sensor measurement data comprises a set of previously-recorded measurements from one or more sensors.