A remote controlled demolition robot (10) comprising a controller (17) and at least one actuator (12) controlled through a hydraulic system (400) comprising at least one valve (13a) connected to a corresponding actuator for a tool (11b) and a pump (410). The controller (17) is configured to operate in a first mode wherein the fluid flow is controlled through the at least one valve (13a), wherein said valve (13a) is a proportional valve, receive a pressure indication indicating a pressure in the hydraulic system (400) and determine if the pressure in the hydraulic system (400) is above a first mode threshold and/or if a pressure change fulfills a first mode condition, and if so operate in a second mode wherein the at least one valve (13a) is in an opened state and the fluid flow is controlled through the pump (410).

A shovel includes a swing hydraulic motor configured to swing a rotating structure, a swing drive hydraulic circuit configured to drive the swing hydraulic motor, an assist hydraulic motor connected to an engine and configured to be supplied with hydraulic oil discharged from the swing drive hydraulic circuit, and a controller configured to control the driving of the shovel. The controller is configured to detect the load condition of the engine, and control the supply of the hydraulic oil to the assist hydraulic motor at the time of deceleration of the swing hydraulic motor, based on the detected load condition.

A method is provided for controlling a hydraulic cylinder in a work machine, which hydraulic cylinder is arranged to move an implement that is subjected to a load, with the hydraulic cylinder being controlled by a hydraulic machine. The method includes detecting that a lifting movement of the implement is to be initiated, and attaining a basic speed of the hydraulic machine before lifting takes place.

A method of controlling a hydraulic system, the hydraulic system including a ram cylinder unit having a cylinder and a ram, and a hydraulic pump and a reservoir used to supply hydraulic fluid to the cylinder, and hydraulically driving the ram using the hydraulic fluid so as to move against a specific load, the method includes determining what a present state is one of an initial state, a proportional steady state, and a later state, controlling the pumping rate, which is obtained by adding the flow rate corresponding to the volume loss due to the compression of the hydraulic fluid thereto, to control the ram in the initial state, and controlling the pumping rate, which is obtained by subtracting the flow rate corresponding to volume recovery of the hydraulic fluid due to the relief of compression of the hydraulic fluid therefrom, to control the ram in the later state.

A two-stage speed controller includes a main body including a first port and a second port in communication with each other, and a primary channel and a secondary channel for fluid to flow therethrough. The secondary channel allows flowing in a single direction to a pressure accumulation chamber. A sliding-axle seat is arranged in the second port. An end of a sliding axle assembly forms, together with the sliding-axle seat, a valve. The pressure accumulation chamber is connected with a primary throttle channel. The sliding axle assembly is formed, in a transverse direction, with a secondary throttle channel. During ingress and discharging of the fluid, all the channels and movement of the valve together allow for control of the pressure of the fluid according to a magnitude of a spring force of a regulation assembly in order to control a moving speed of a cylinder connected to the main body.

A two-stage speed controller includes a main body including a first port and a second port in communication with each other, and a primary channel and a secondary channel for fluid to flow therethrough. The secondary channel allows flowing in a single direction to a pressure accumulation chamber. A sliding-axle seat is arranged in the second port. An end of a sliding axle assembly forms, together with the sliding-axle seat, a valve. The pressure accumulation chamber is connected with a primary throttle channel. The sliding axle assembly is formed, in a transverse direction, with a secondary throttle channel. During ingress and discharging of the fluid, all the channels and movement of the valve together allow for control of the pressure of the fluid according to a magnitude of a spring force of a regulation assembly in order to control a moving speed of a cylinder connected to the main body.

The disclosed invention relates to a swing control system for construction machines and is useful in a construction equipment in which the shaking or jerking movement of the upper swing structure due to the moment of inertia thereof is controlled by a simple electrical hydraulic control system so that although the swing manipulation is abruptly and repeatedly performed during the excavation or dumping operation, an operator can control the soft swing start/stop of the upper swing structure in the swing operation of construction machine, thereby improving manipulability and work efficiency of the work apparatus.

A crane, in particular a mobile crane, having a closed hydraulic circuit in which a hydraulic pump is hydraulically connected to at least one hydraulic motor via a feed and a discharge, and in which the feed is hydraulically connected to the discharge via at least one bypass which bypasses the at least one hydraulic motor, wherein the at least one bypass includes a continuously adjustable valve for variably controlling the fluid flow bypassing the at least one hydraulic motor. In addition, a corresponding control device and a corresponding crane control program for actuating a closed hydraulic circuit of a crane are provided.