Three-freedom-degree parallel robot adjustable in arm length

The invention discloses a three-freedom-degree parallel robot adjustable in arm length. The three-freedom-degree parallel robot is characterized by comprising a static platform provided with a motor supporting seat, three groups of identical branch structures, a movable platform, and a plurality of joint bearings, each branch structure is provided with a reducer connected with a motor, an arm-length-adjustable drive arm assembly, and a length-adjustable driven arm, the reducers are fixed on the static platform through the motor supporting seat, the drive arm assemblies are connected with the reducers and are fixed on the static platform through the joint bearings, one end of each driven arm is connected with each drive arm assembly through one joint bearing, and the other end of each driven arm is connected with the movable platform through one bearing joint so as to drive the movable platform to move in three directions. The three-freedom-degree parallel robot is concise in structure, reasonable in transmission, capable of ensuring good rigidity and strength, high in motion precision, wide in working space, good in flexibility, convenient to install and debug, and suitable for application and popularization.