US Patent 10317304 Screwdriver test bench

A test bench for screwdrivers comprises a hydraulic brake unit (11) provided with a coupling (12) for a screwdriver to be tested and angle and torque measurement transducers (15). The brake unit (11) is supplied by a proportional electrovalve (16) under the control of a PID controller (19) which receives an electrovalve control signal (22) from a control unit (26) so as to follow braking curves depending on the angle of rotation and/or torque measured. The bench comprises a memory (21) for storing different sets of parameters for the PID controller (19), which can be selected by the control unit (26) so as to have different control characteristics. A method for controlling the bench is also described.