Work machine

A work machine comprising:

• a fluid pressure actuator that operates a driven body by being driven by supply and discharge of working fluid;
• a pump that supplies the working fluid to the fluid pressure actuator;
• a meter-in control valve capable of controlling a flow rate of the working fluid supplied from the pump to the fluid pressure actuator;
• a meter-out control valve capable of controlling a flow rate of the working fluid discharged from the fluid pressure actuator;
• an operation device that outputs an operation signal giving an instruction for driving of the fluid pressure actuator;
• and
• a controller that controls the pump, the meter-in control valve, and the meter-out control valve,
• the controller being configured to
• compute a target velocity of the fluid pressure actuator according to the operation signal from the operation device,
• compute target thrust or target torque of the fluid pressure actuator on a basis of a driven state of the fluid pressure actuator, and
• control a velocity of the fluid pressure actuator by the meter-out control valve on a basis of the operation signal from the operation device and control at least one of the pump and the meter-in control valve such that a pressure on a meter-in side of the fluid pressure actuator is equal to or higher than a predetermined value, in a case a positive or negative sign of the target velocity as a computation result is different from a positive or negative sign of the target thrust or the target torque as a computation result,
• the work machine comprising:
• a first pressure sensor that senses a delivery pressure of the pump;
• and
• a second pressure sensor that senses the pressure on the meter-in side of the fluid pressure actuator, wherein
• the controller is configured to compute the target thrust or the target torque on a basis of the target velocity as a computation result, and
• the controller is configured to, in a case the positive or negative sign of the target velocity as a computation result is different from the positive or negative sign of the target thrust or the target torque as a computation result,
• set a meter-in target pressure as a target value of the pressure on the meter-in side of the fluid pressure actuator to the predetermined value or higher,
• compute a meter-out target pressure as a target value of a pressure on a meter-out side of the fluid pressure actuator on a basis of the target thrust or the target torque as a computation result and the set meter-in target pressure,
• control the meter-out control valve by using the meter-out target pressure as a computation result,
• control the pump on a basis of the set meter-in target pressure and a sensed value obtained by the first pressure sensor, and
• control the meter-in control valve on a basis of the set meter-in target pressure and a sensed value obtained by the second pressure sensor.