Development of Wi-Fi-Based Teleoperation System for Forest Harvester

Purpose: To develop a teleoperation system for forest harvesters using images from the work area. Methods: In a CPE (customer premises equipment) environment, both the control command to operate a forest harvester and images to monitor the work area are transmitted using 5.8 GHz Wi-Fi. The control command is sent to the harvester by wirelessly connecting CAN (controller area network) buses in the harvester and remote control station. The images are sent to the operator through video streaming over Wi-Fi. To evaluate the feasibility of the proposed teleoperation system, the delays for transmitting control commands and images are measured in various environments such as open space, a space with obstacles, and a forest. Results: The total delay comprised the wireless communication delay and the time required to properly format the data for transmission over Wi-Fi. The delay of CAN-to-Ethernet and Ethernet-to-CAN conversion for transmitting CAN bus data and the delay due to the encoding/decoding of transmitted images were 0.213 and 119.457 ms, respectively. The wireless communication delay was maximum 3.506 ms. Provided that the reception sensitivity did not exceed the capability of the receiving antenna, the data loss did not occur. A field test conducted over 350 m on a relatively flat surface showed that the operator could suitably teleoperate all the harvester actuators and functions by using joysticks and switches under video guidance. Conclusion: A teleoperation system was developed for a forest harvester. The system consists of control command transmission and image transmission over Wi-Fi CPE. The delay between the environment recognition by the operator and actuator control was acceptable according to the operator’s assessment and various studies. © 2021, The Korean Society for Agricultural Machinery.