Provided is a work machine that, within the limit of not harming dynamic stability, can perform work utilizing the impact generated when a cylinder driving a front work implement collides with a stroke end. A drive control system 34 includes: a stroke end distance calculation and evaluation section 34c that determines whether or not it is possible for cylinders 20A and 21A to collide with a stroke end; a dynamic center of gravity position prediction section 34d that, when the stroke end distance calculation and evaluation section determines that it is possible for the cylinders to collided on the stroke end, predicts a trajectory of the dynamic center of gravity position of a hydraulic excavator 1 from a time when a decelerating operation of the cylinder starts to a time when the cylinder stops; and an allowable velocity changing section 34f that changes the allowable velocity of the cylinder according to a minimum distance from the trajectory of the dynamic center of gravity position predicted by the dynamic center of gravity position prediction section to a tipping line of the hydraulic excavator.

An electrohydraulic poppet valve device control system includes a main body, an extend poppet valve, a retract valve body, a retract poppet valve, and an actuator. The actuator is movable to an extend position, a retract position, and a null position, and moves to, or remains in, the null position when electrical power is not supplied to the actuator. In the extend position, the extend poppet valve is in its open position and the retract poppet valve is in its closed position. In the retract position, the extend poppet valve is in its closed position and the retract poppet valve is in its open position. In the null position, the extend poppet valve is in its closed position and the retract poppet valve is in its closed position.

A method of controlling wash equipment in an automated vehicle wash system having a conveyor includes, measuring one or more contours of a vehicle as the vehicle moves thorough an entry area of the automated vehicle wash system on the conveyor; tracking the distance a fixed point relative to the conveyor moves; associating the one or more contours of the vehicle with the position of the fixed point; determining, based on the one or more contours of the vehicle and the position of the fixed point, commands for operating the wash equipment; delivering the commands to the wash equipment; and operating the wash equipment in accordance with the commands.

A method of controlling wash equipment in an automated vehicle wash system having a conveyor includes, measuring one or more contours of a vehicle as the vehicle moves thorough an entry area of the automated vehicle wash system on the conveyor; tracking the distance a fixed point relative to the conveyor moves; associating the one or more contours of the vehicle with the position of the fixed point; determining, based on the one or more contours of the vehicle and the position of the fixed point, commands for operating the wash equipment; delivering the commands to the wash equipment; and operating the wash equipment in accordance with the commands.

A hydraulic drive system of construction machine including: turning motor; turning operation device that outputs turning operation signal corresponding to inclination angle of operating lever; turning direction switching valve including spool and driver, driver receiving command current and driving spool, turning direction switching valve increasing amount of hydraulic liquid supplied to turning motor and amount of hydraulic liquid discharged from turning motor with increase in command current; controller that feeds command current to turning direction switching valve, wherein command current increases in accordance with increase in turning operation signal; and pressure sensor that detects outflow pressure of turning motor. Where turning operation signal decreases, when outflow pressure of turning motor, which is detected by pressure sensor, is higher than threshold and is increasing, controller feeds command current to turning direction switching valve, wherein a moving speed of spool is kept to be less than or equal to limiting value.

A compressed air provision device (2) for aerating a first pressure chamber (10) of a pneumatic actuator in order to actuate an actuator element (11) of the pneumatic actuator (3) in accordance with an actuation specification, in particular a position, movement, pressure and/or force specification. The compressed air provision device (2) is configured to calculate an aeration period (bd) and to aerate the first pressure chamber (10) in accordance with the calculated aeration period (bd) in order to bring about actuation of the actuator element (11) in accordance with the actuation specification.

A power unit with manual override control for a hydraulic system having an initial state and at least one operational state is provided, comprising: a tank for storing hydraulic fluid that moves between a first chamber and a second chamber of a hydraulic cylinder; a pump that routes the hydraulic fluid in and out of the tank; a first relief valve; a first solenoid valve configured to shift between a plurality of positions based on the at least one operational state of the hydraulic system; a first check valve connected to the first solenoid valve; a manual override control unit comprising: a second check valve; and a second solenoid valve configured to shift between a plurality of positions based on activation of a manual override control, wherein the activation of the manual override control returns the hydraulic system from the at least one operational state to the initial state.

The self-contained energy efficient hydraulic actuator system of the present invention includes a hydraulic cylinder, a servo motor that is configured to produce rated torque from zero RPM to maximum rated RPM with rotor speed/position feedback to a servo motor, a pump, and a solenoid valve that enables the hydraulic cylinder to maintain its position without the motor running. The system has the ability to hold a load in place without motor operation via the use of the solenoid valve, and therefore saves energy and extends the motor lifetime by minimizing the motor running time.

A hydraulic drive apparatus includes: an electric motor; a variable displacement pump driven by the electric motor, the pump including a pair of pump ports whose delivery side and suction side are switched with each other in accordance with a rotation direction of the electric motor; a hydraulic actuator connected to the pair of pump ports by a first supply/discharge line and a second supply/discharge line; and a control device that controls the electric motor based on an actuator position command value for the hydraulic actuator. The pump is configured such that a volume of the pump decreases in accordance with increase in a pressure difference between the first supply/discharge line and the second supply/discharge line.

A hydraulic drive apparatus includes: an electric motor; a variable displacement pump driven by the electric motor, the pump including a pair of pump ports whose delivery side and suction side are switched with each other in accordance with a rotation direction of the electric motor; a hydraulic actuator connected to the pair of pump ports by a first supply/discharge line and a second supply/discharge line; and a control device that controls the electric motor based on an actuator position command value for the hydraulic actuator. The pump is configured such that a volume of the pump decreases in accordance with increase in a pressure difference between the first supply/discharge line and the second supply/discharge line.