The development of heave compensation systems in marine engineering and deep-sea mining applications is analyzed, and their functional requirements and key features are summarized. Based on this analysis, a system is proposed that uses flexible joints to compensate for pitch and roll motion, along with a single-chamber valve-controlled compensation cylinder with a high-pressure accumulator to compensate for heave motion. An active heave compensation system based on this design is studied using a fuzzy PID control method. A dynamic model of the system is then established for this control system. Numerical simulations are carried out to evaluate the control process and performance under different sea conditions. The results show that the proposed heave compensation system offers distinct advantages such as a simple and compact structure, minimal deck space requirements on the mining vessel, and large compensation angles for both pitch and roll. Furthermore, the use of a fuzzy PID control method for heave compensation achieves a relatively good compensation effect, and can be adapted to varying sea conditions.

In view of the requirements and characteristics of a deep-sea polymetallic nodule collector’s movements according to a planned path and speed during operation, a collector trajectory tracking system scheme based on virtual target vehicle reference is proposed. In this system, the virtual target vehicle moves according to the planned path and speed, thereby generating a dynamic target path and speed. A fuzzy controller calculates the collector’s angular-velocity command based on the lateral position deviation and the heading-angle deviation between the collector and the target vehicle, and a proportional controller calculates the collector’s body linear velocity control command based on the longitudinal position deviation between the collector and the target vehicle. By integrating these two commands, the collector tracks the target vehicle and thereby realizes trajectory tracking of the planned path and speed. A control system is designed, and simulation studies are carried out. The results show that the designed system enables the collector to track the planned path and speed well under operational conditions. The trajectory tracking method based on virtual target vehicle reference can also form an organic integration of path planning and trajectory tracking, generate dynamic planned paths and speeds for the entire mining area, and realize movement of the collector along the planned path and speed throughout the whole operation.

In view of the requirements and characteristics that a deep-sea polymetallic nodule collector must travel according to a planned path and speed during operation, a collector trajectory tracking system scheme based on virtual target vehicle following is proposed. In this system, the virtual target vehicle travels according to the planned path and speed, thereby generating a dynamic target path and speed. A fuzzy controller calculates the collector’s angular-velocity command based on the lateral position deviation and the heading-angle deviation between the collector and the target vehicle, and a proportional controller calculates the collector’s body linear velocity control command based on the longitudinal position deviation between the collector and the target vehicle. By integrating these two commands, the collector follows the target vehicle and thereby realizes trajectory tracking of the planned path and speed. A tracking system is designed and simulation studies are carried out. The results show that the designed system enables the collector to follow the planned path and speed well under operational conditions. The trajectory tracking method based on virtual target vehicle following can also form an organic integration of path planning and trajectory tracking, generate dynamic planned paths and speeds for the entire mining area, and realize tracking travel of the collector along the planned path and speed throughout the whole operation.