Four-degree-of-freedom series-parallel combined heavy-load mechanical arm

The invention discloses a four-degree-of-freedom series-parallel combined heavy-load mechanical arm, wherein a rack is connected with an upper frame, the upper frame can rotate for a complete cycle relative to the rack, and is hinged with the lower end of a large arm, the upper end of the large arm is hinged with one end of a small arm, the other end of the small arm is hinged with one fulcrum ofan end effector, the middle part of the small arm is respectively hinged with the end parts of piston rods of a pair of small arm cylinders, and cylinder sleeves of the small arm cylinders are respectively hinged with the through holes of the other end of the upper frame; the middle part of the large arm is respectively hinged with the end parts of cylinder sleeves of a pair of large arm cylinders, and the end parts of piston rods of the large arm cylinders are respectively connected with the upper frame; the lower ends of support rods are hinged with the upper frame, and the upper ends of the pair of support rods are respectively hinged with a pair of rockers; the rockers are also respectively connected with the end parts of piston rods of a pair of end effector cylinders through anotherpair of hinges, and the end parts of cylinder sleeves of the end effector cylinders are connected with the other fulcrum of the end effector; and the pair of symmetrical rockers are hinged with the middle part of the large arm, and three hinges on the rockers are in triangle distribution. The invention has the advantages of high bearing capability, large work space, correct movement, easiness in inverse solution and realized real-time control.