Abstract: A drive system with both fixed-displacement hydraulic motors and variable-displacement hydraulic motors for a cutter head of a boring machine and a control method thereof are provided. The drive system includes a variable-displacement hydraulic motor group, a fixed-displacement hydraulic motor group and a variable-displacement hydraulic pump group. The variable-displacement hydraulic motor group, the fixed-displacement hydraulic motor group, and the variable-displacement hydraulic pump group are all connected to a main oil circuit of a cutter head system of the boring machine. The variable-displacement hydraulic pump group inputs flow to the main oil circuit; and, the variable-displacement hydraulic motor group and the fixed-displacement hydraulic motor group acquire flow from the main oil circuit. Displacements of the fixed-displacement hydraulic motor group and the variable-displacement hydraulic motor group are set in a way of specific displacement combination.

Abstract: Provided is an offshore crane heave compensation control system and method using video rangefinding to achieve heave compensation in a directly driven pump-controlled electro-hydraulic heave compensator. The heave compensation and the heave compensator are applicable for special operation and control requirements on a fixed offshore platform and allow the crane to achieve steady lifting of a load away from or lowering of a load on to a supply vessel without being influenced by the motion of the supply vessel caused by ocean currents, ocean winds, or ocean waves. Also provided is a test platform for the offshore crane heave compensation control system using video rangefinding. The test platform provides a realistic simulation for all lifting and lowering processes of an offshore platform crane in offshore environments to study the motion control of the provided system.

Abstract: A drive system with both fixed-displacement hydraulic motors and variable-displacement hydraulic motors for a cutter head of a boring machine and a control method thereof are provided. The drive system includes a variable-displacement hydraulic motor group, a fixed-displacement hydraulic motor group and a variable-displacement hydraulic pump group. The variable-displacement hydraulic motor group, the fixed-displacement hydraulic motor group, and the variable-displacement hydraulic pump group are all connected to a main oil circuit of a cutter head system of the boring machine. The variable-displacement hydraulic pump group inputs flow to the main oil circuit; and, the variable-displacement hydraulic motor group and the fixed-displacement hydraulic motor group acquire flow from the main oil circuit. Displacements of the fixed-displacement hydraulic motor group and the variable-displacement hydraulic motor group are set in a way of specific displacement combination.

Abstract: Provided is an offshore crane heave compensation control system and method using video rangefinding to achieve heave compensation in a directly driven pump-controlled electro-hydraulic heave compensator. The heave compensation and the heave compensator are applicable for special operation and control requirements on a fixed offshore platform and allow the crane to achieve steady lifting of a load away from or lowering of a load on to a supply vessel without being influenced by the motion of the supply vessel caused by ocean currents, ocean winds, or ocean waves. Also provided is a test platform for the offshore crane heave compensation control system using video rangefinding. The test platform provides a realistic simulation for all lifting and lowering processes of an offshore platform crane in offshore environments to study the motion control of the provided system.