I've seen in the past a different trick that is adding an IMU[1] to the robot arm. When combining two different types of sensors, it's called Sensor Fusion[2],

I've seen in the past a different trick that is adding an IMU[1] to the robot arm. When combining two different types of sensors, it's called Sensor Fusion[2], and it's really common to put together a IMU with GPS and slap a Kalman Filter[3] for very accurate position reading. The particularly cool thing of this video though is that they could mount the new sensor within the motor itself, making it all a lot more compact. [1] https://en.wikipedia.org/wiki/Inertial_measurement_unit https://en.wikipedia.org/wiki/Inertial_measurement_unit [2] https://en.wikipedia.org/wiki/Sensor_fusion https://en.wikipedia.org/wiki/Sensor_fusion [3] https://en.wikipedia.org/wiki/Kalman_filter https://en.wikipedia.org/wiki/Kalman_filter