摘要:
A drive control system of a hydraulic excavator includes a control device. When accelerating a turning body to a target turning speed, the drive control device controls an operation of the electric motor driving device such that the electric motor outputs high efficiency torque by which a highest electric power efficiency is obtained at the target turning speed. The control device controls an operation of an oil pressure supply device such that residual torque obtained by subtracting the high efficiency torque from target torque is output from an oil-pressure motor.
摘要:
The hybrid excavator includes: a first detection sensor for detecting an RCV-manipulated quantity; a second detection sensor for detecting the rotational speed of an electric motor; a hydraulic pump-motor connected to the electric motor; a hydraulic cylinder connected to the hydraulic pump-motor; first and second hydraulic valves installed in first and second passages, respectively, between the hydraulic pump-motor and the hydraulic cylinder; a third hydraulic valve for compensating for or bypassing a flow rate and a controller for receiving an RCV-manipulation signal from the first detection sensor and the rotational speed of the electric motor from the second detection sensor to compare the received values to data of previously stored working conditions, to output a control signal for switching the first and second hydraulic valves, and to block a working fluid from returning into the hydraulic cylinder, so as to thereby quickly stop the working device.
摘要:
A method is provided for controlling movement of a first vehicle component relative to a second vehicle component, including the steps of determining a deceleration rate of the first vehicle component in order to achieve a predetermined final speed at a final position, determining a starting position for initiating the deceleration on the basis of the predetermined final speed, the final position and the determined deceleration rate and controlling deceleration of the component from the starting position to the final position according to the determined acceleration rate.
摘要:
A fluid power control system for load handling mobile equipment includes a pair of hydraulic actuators for moving respective cooperating load-engaging members selectively toward or away from each other, or in a common direction, at respective asynchronous speeds to selectively attain either synchronous or asynchronous respective positions of the actuators. The actuators have sensors enabling a controller to monitor their respective movements and correct unintended differences in the actuators' respective movements, such as unintended differences in relative intended positions, speeds, or rates of change of speeds. Respective hydraulic valves responsive to the controller separately and nonsimultaneously decrease respective flows through the respective actuators to more accurately and rapidly correct differences from the intended relative movements of the actuators.
摘要:
A method is provided for controlling movement of a first vehicle component relative to a second vehicle component, including the steps of determining a deceleration rate of the first vehicle component in order to achieve a predetermined final speed at a final position, determining a starting position for initiating the deceleration on the predetermined final speed, the final position and the determined deceleration rate and controlling deceleration of the component from the starting position to the final position according to the determined acceleration rate.
摘要:
A control device for a work machine on a construction vehicle is provided so that a bucket cylinder is stopped at a target position, with high accuracy achieved in a bucket cylinder length, and with chock held down to a low level. A bucket cylinder length detection section refereces a cylinder length detection table on the basis of a boom angle and a bell crank angle, thereby detecting a bucket cylinder length. A bucket attitude control section controls the bucket cylinder length so that a target position will be reached. Feedback control is performed until a set value which is set short of a target value is reached. After the bucket cylinder length reaches the set value, open loop control is performed until the target value is reached.
摘要:
A control valve device comprises two direction control valves. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. When a hoist cylinder is telescopically operated to raise or lower a vessel, as the hoist cylinder (10) approaches a stop position, a controller determines that the hoist cylinder gets close to the stop position. Based upon this determination, the controller variably adjusts a flow passage area of the direction control valve using the variable throttle portions or variably adjusts a flow passage area of the direction control valve using the variable throttle portions in such a manner as to slow down or speed up the telescopic speed of the hoist cylinder corresponding to the weight in the side of vessel.
摘要:
A hydraulic system is provided, having a pump, operably connected to a motor. It also comprises a controller-driven hydraulic actuator, operably connected to the pump and a hydraulic valve, operable to direct hydraulic fluid to and from either a rod side or a cylinder side of the hydraulic actuator. Rod and cylinder side pressures are pre-defined based on the instantaneous acceleration or deceleration required. Decelerating the hydraulic actuator could involve maintaining the current pressure in the meter-out side of the hydraulic actuator and decreasing the current pressure in the meter-in side by varying the speed of the pump. Deceleration of the hydraulic actuator could also include decreasing pressure on the meter-in side of the hydraulic actuator at a higher rate than on the meter-out side. Acceleration is achieved using a similar approach.
摘要:
A method of actuating a piston having a first side and a second side includes the steps of generating a counter-ventilation pulse having a duration and amplitude defined to achieve a predetermined operating speed of the piston and a predetermined damping of a final position of a piston, applying an actuating pressure to the first side of the piston, and venting a second side of the piston in a defined manner using the counter-ventilation pulse so as to prevent a buildup of a maximum possible ventilation pressure.
摘要:
A pneumatic unlocking and closing apparatus for doors has a soft braking phase at each end position. The apparatus includes a pneumatic piston-cylinder unit having a working chamber acting on a large piston area and a return chamber acting on a piston area which is reduced by the piston rod. The apparatus is operated by a substantially closed pressure actuation system having a compressed air pump creating both a working pressure in the working chamber and a less high counter pressure in the return chamber. The pressure system includes a first or plus tank having a certain predetermined high pressure to act as the working pressure in the working chamber for expelling the piston during the ordinary working stroke thereof; and a second or minus tank into which the air of the working chamber is evacuated when the piston is to be returned to its fully retracted position.