This technology is a control system and method for remotely operated excavators. It equips the excavator's body, boom, arm, and attachment with inertial sensors, compares the expected posture estimated from remote control signals with the actual posture measured by the sensors, and automatically stops the excavator if the difference exceeds a permissible threshold.
While remote operation allows excavators to work in hazardous areas inaccessible to humans, the process—from operator input and signal transmission to machine movement and status feedback—involves significant latency. Due to this delay, operators often fail to detect overloads in time, such as when a bucket hits an unexpected obstacle, leading to malfunctions or equipment damage.
This technology calculates the expected posture by adding the commanded posture change to the current posture stored in memory. An overload detection unit monitors the difference from the actual posture and immediately cuts off drive signals if the threshold is exceeded, updating the current posture to the actual one for subsequent commands. The system adjusts the threshold based on reaction forces measured by attachment pressure sensors or increases it based on the frequency of overloads to reduce unnecessary stops during work on hard ground. It also transmits overload signals and actual posture data back to the control unit. Applicable to disaster debris removal, demolition of unstable structures, and unmanned excavation in hazardous environments like nuclear plants or mines, it enables equipment to detect and stop at abnormal loads locally despite communication delays, preventing damage to hydraulic systems and work tools.
This invention was developed with support from the Ministry of Trade, Industry and Energy through a joint Korea-US research project on next-generation core robot technologies for disaster rescue and humanitarian aid.
US11459728B2, WO2020-138708A1
