Linear speed of the lead screw rotation x Torque amplified through the reducer T addĪdditional torque of the distributed linear drive system T lĮquivalent load torque of the servo motor u d Pressures of the EMHA rodless and rod chamber, respectively P hĭriving power of the hydraulic cylinder R Moment of inertia driven by the electrical unit J lĮquivalent moment of inertia of the load J s Moments of inertia of the servo motor rotor and reducer, respectively Je: Radial force of the driving rod of SHA F l Hydraulic transmission mechanism force F h Interference force including friction F h Radial force of the driving rod of EMA F f Wheelbase between the driving gear and the driven gear Fe:Įlectromechanical transmission mechanism force F e Wheelbase between the servo motor and the lead screw Dz2: Outer diameter of the cylinder barrel ds:ĭiameters of the piston and piston rod, respectively De: Rotational viscous friction coefficient c Compared with the valve-controlled hydraulic cylinder system, EMHA exhibits a velocity tracking error and energy consumption reduced by 49.7% and 54%, respectively, under the same working conditions.Įlectromechanical-hydraulic hybrid actuator SHA:Įffective action areas of the EMHA rodless and rod chamber pressure, respectively B The test results prove that the EMHA has good working characteristics and high energy efficiency. Finally, the EMHA prototype and test platform are manufactured. Then, the mathematical model, structure, and parameter design of the new EMHA are studied. The control scheme of the electromechanical transmission mechanism is used for motion control, and the hydraulic transmission mechanism is used for power assistance. The piston of the hydraulic transmission mechanism and the ball screw pair of the electromechanical transmission mechanism are mechanically fixed together through screw bolts, realizing the integration of two types of transmission mechanisms. EMHA mainly features two transmission mechanisms. This study proposes and designs a novel electromechanical-hydraulic hybrid actuator (EMHA) that integrates the advantages of EMA and SHA. However, they cannot easily drive heavy-duty mechanisms because of weak bearing capacity. Electromechanical actuators (EMAs) possess superior energy efficiency and motion characteristics. However, their energy efficiency is low, and their motion characteristics are inevitably affected by uncertain nonlinearities.
Servo-hydraulic actuators (SHAs) are widely used in mechanical equipment to drive heavy-duty mechanisms.
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