Dual-coder angle detecting system for torsion test of torsion shaft

The invention relates to a dual-coder angle detecting system for the torsion test of a torsion shaft. The system can be used for precisely measuring and displaying the torsion angle and eliminating the rotation angle clearance of the torsion shaft. By adopting the system, the torsion shaft can rotate precisely by a certain angle according to numerical control instructions, thus ensuring that the torsion shaft is at a free state after the releasing of the torsion shaft is finished. A clearance sliding block combination mechanism is adopted; during the rotating of the torsion shaft and the torque releasing of the torsion shaft, the starting and stopping of a servo motor can be controlled by the difference of the collected readings of the two coders; therefore, an appropriate pre-torsion strain angle can be determined more exactly, the material performance can be played to a maximum degree, and the requirement on production technology of the torsion shaft can be met.