A new torque-loading method based on the direct torque control strategy for double motorized spindles is developed to achieve simulating the actual static and dynamic torque conditions and reduce the error of centration for back-toback drive reliability bench test of double motorized spindles. First, the direct torque control theory and dynamometer control strategy of two motorized spindles are discussed, and then the control model of the motorized spindle is developed in the d-q coordinate system based on the direct torque control theory. In order to verify the proposed control model, the direct torque control strategy simulation model of double motorized spindles is constructed, and the virtual simulation tests are conducted. Finally, the torque-loading experiments controlled by the direct torque control theory with 10 and 7.3 kW motorized spindles are performed. Experimental results show that the profile of the desired torque can be accurately followed and the proposed dynamometer system has a good response ability of speed and torque.

Passenger seats of Electric multiple-unit (EMU) influence environmental performance. Formaldehyde and other volatile organic compounds in the nonmetallic material of the seat is volatized. Toxic gas is produced by seat material combustion. This study chooses a typical passenger seat and proposes optimization strategies based on the experiment. First, the source of seat formaldehyde and volatile organic compounds is determined through a test. Four optimization strategies, including foaming pretreatment, foaming formula improvement, binder optimization, and bioenzyme spraying, are proposed. Second, the source of toxic gases in the seat is determined through a combustion test on the seat and its nonmetallic materials. Moreover, the optimization strategy for controlling the material of seat fabric is formulated.