The present application discloses a steering control system, a method and a crane. The steering control system includes: one or more first angle sensors, one or more second angle sensors, and a steering controller; each of the first angle sensors collects an actual steering angle of a wheel corresponding to a mechanical steering axle as a first steering angle; each of the second angle sensors an actual steering angle of a wheel corresponding to an electrically controlled steering axle as a second steering angle; the steering controller obtains a theoretical steering angle of the wheel corresponding to the electrically controlled steering axle in a corresponding travel mode according to the first steering angle, and compares the second steering angle with the theoretical steering angle, to control the wheel corresponding to the electrically controlled steering axle to steer according to a difference therebetween.

The present application discloses a steering control system, a method and a crane. The steering control system includes: one or more first angle sensors, one or more second angle sensors, and a steering controller; each of the first angle sensors collects an actual steering angle of a wheel corresponding to a mechanical steering axle as a first steering angle; each of the second angle sensors an actual steering angle of a wheel corresponding to an electrically controlled steering axle as a second steering angle; the steering controller obtains a theoretical steering angle of the wheel corresponding to the electrically controlled steering axle in a corresponding travel mode according to the first steering angle, and compares the second steering angle with the theoretical steering angle, to control the wheel corresponding to the electrically controlled steering axle to steer according to a difference therebetween.

A trailer assembly includes first and second axles supporting first and second wheels which are coupled to first and second actuators of a steering system. The steering system includes a control circuit connected to the actuators and the control circuit includes a driving device configurable in a low speed maneuvering mode with: a synchronized sub-mode in which the actuators can be actuated in a synchronized manner to steer the wheels in a synchronized manner, and a desynchronized sub-mode in which the first and second actuators can be actuated individually and independently to steer only the first wheels or only the second wheels. A control device is connected to the driving device to: select one of the sub-modes in the low speed maneuvering mode, and select an actuation either of the first actuator or of the second actuator, in the desynchronized sub-mode.

A trailer assembly includes first and second axles supporting first and second wheels which are coupled to first and second actuators of a steering system. The steering system includes a control circuit connected to the actuators and the control circuit includes a driving device configurable in a low speed maneuvering mode with: a synchronized sub-mode in which the actuators can be actuated in a synchronized manner to steer the wheels in a synchronized manner, and a desynchronized sub-mode in which the first and second actuators can be actuated individually and independently to steer only the first wheels or only the second wheels. A control device is connected to the driving device to: select one of the sub-modes in the low speed maneuvering mode, and select an actuation either of the first actuator or of the second actuator, in the desynchronized sub-mode.

A hydraulic system for controlling a pair of steerable caster wheels includes a left side actuator and a right side actuator. A rear steering control valve is moveable between a first state for disabling direct control of the left and side actuators and a second state for enabling direct control the left and right side actuators to provide a steer response. A fluid connection continuously connects the pressure source and the fluidic tie rod fluid circuit in fluid communication when the rear steering control valve is disposed in one of the first state and the second state to continuously supply the pressurized fluid to the fluidic tie rod fluid circuit.

A hydraulic system for controlling a pair of steerable caster wheels includes a left side actuator and a right side actuator. A rear steering control valve is moveable between a first state for disabling direct control of the left and side actuators and a second state for enabling direct control the left and right side actuators to provide a steer response. A fluid connection continuously connects the pressure source and the fluidic tie rod fluid circuit in fluid communication when the rear steering control valve is disposed in one of the first state and the second state to continuously supply the pressurized fluid to the fluidic tie rod fluid circuit.

A hydrostatic drive includes a transmission having a pump and motor disposed on a center section, and a charge pump to provide fluid to a charge gallery. A power take off (PTO) driven by a prime mover includes a clutch assembly, solenoid valve, and PTO drive member driven by a prime mover input. When the solenoid valve is in a first position, fluid flows from the charge gallery to the clutch to connect the input with the PTO drive member, and when the solenoid valve is in a second position, fluid flows from the PTO mechanism to the sump to disengage the PTO drive member from the input. A filter may be disposed on a land on the center section and seated in a filter pocket in the housing. The filter engages with a bottom surface of the filter pocket to maintain a seal against the land.

A hydrostatic drive includes a transmission having a pump and motor disposed on a center section, and a charge pump to provide fluid to a charge gallery. A power take off (PTO) driven by a prime mover includes a clutch assembly, solenoid valve, and PTO drive member driven by a prime mover input. When the solenoid valve is in a first position, fluid flows from the charge gallery to the clutch to connect the input with the PTO drive member, and when the solenoid valve is in a second position, fluid flows from the PTO mechanism to the sump to disengage the PTO drive member from the input. A filter may be disposed on a land on the center section and seated in a filter pocket in the housing. The filter engages with a bottom surface of the filter pocket to maintain a seal against the land.

A trailer assembly includes first and second axles supporting first and second wheels which are coupled to first and second actuators of a steering system. The steering system includes a control circuit connected to the actuators and the control circuit includes a driving device configurable in a low speed maneuvering mode with: a synchronized sub-mode in which the actuators can be actuated in a synchronized manner to steer the wheels in a synchronized manner, and a desynchronized sub-mode in which the first and second actuators can be actuated individually and independently to steer only the first wheels or only the second wheels. A control device is connected to the driving device to: select one of the sub-modes in the low speed maneuvering mode, and select an actuation either of the first actuator or of the second actuator, in the desynchronized sub-mode.

A trailer assembly includes first and second axles supporting first and second wheels which are coupled to first and second actuators of a steering system. The steering system includes a control circuit connected to the actuators and the control circuit includes a driving device configurable in a low speed maneuvering mode with: a synchronized sub-mode in which the actuators can be actuated in a synchronized manner to steer the wheels in a synchronized manner, and a desynchronized sub-mode in which the first and second actuators can be actuated individually and independently to steer only the first wheels or only the second wheels. A control device is connected to the driving device to: select one of the sub-modes in the low speed maneuvering mode, and select an actuation either of the first actuator or of the second actuator, in the desynchronized sub-mode.