Intelligent load-sensing electro-hydrostatic actuator

A smart load-sensing EHA, comprising a variable displacement hydraulic pump, a symmetrical hydraulic cylinder, a feedback module, a pressure-following valve and an execution mechanism;

• the symmetrical hydraulic cylinder includes a symmetrical plunger, a first cylinder and a second cylinder separated by the plunger;
• the variable displacement hydraulic pump includes an oil inlet and an oil outlet connected with the first cylinder and the second cylinder, respectively;
• the feedback module includes a first input, a second input and an output, the first input and the second input being connected with the first cylinder and the second cylinder, respectively, the output being used to output a greater one of the pressures at the first input and the second input to the execution mechanism;
• the pressure-following valve is connected between the output of the feedback module and an input end of the execution mechanism to reduce an instantaneous flow input to the input end of the execution mechanism;
• the input end of the execution mechanism is connected to the output of the pressure-following valve, and the output end of the execution mechanism is connected to the variable displacement hydraulic pump;
• the execution mechanism is used to receive an output of the feedback module and generate a signal for changing a displacement of the variable displacement hydraulic pump,
• wherein the execution mechanism is a single-acting hydraulic cylinder, the single-acting hydraulic cylinder includes a cylinder body, an asymmetrical plunger and a spring inside the cylinder body;
• the asymmetrical plunger includes a first shaft and a first plug perpendicular to each other;
• the first plug fits with an inner wall of the cylinder body to form a cavity having an opening connected to an output of a damping orifice;
• the spring is arranged inside a cavity with the first shaft of the single-acting hydraulic cylinder and has an elastic direction overlapping with an axis of the first shaft, and works in a non-tensile state;
• one end of the first shaft is fixedly connected with the first plug and the other end is connected with the variable displacement hydraulic pump to change a displacement of the variable displacement hydraulic pump according to a joint force of a pressure applied to the first plug by liquid into the cavity and a pressure applied to the first plug by the spring.