Vehicle speed control method and system under deceleration condition based on chassis dynamometer

The invention discloses a vehicle speed control method and a vehicle speed control system based on a chassis dynamometer under a deceleration condition, wherein the method comprises the following steps: step S1, determining the control condition of entering a deceleration stage; Step S2, judging whether the remaining electric quantity of the test vehicle reaches the energy recovery electric quantity threshold value; If not, executing; step S3 performing deceleration control according to the hub auxiliary braking strategy; If yes, executing step S4 to perform deceleration control according to the energy recovery braking strategy; 5, judging whether that actual deceleration is great than or equal to the target deceleration, and the actual vehicle speed is less than or equal to the target vehicle speed; If so, step S6 putting an end to the deceleration phase control condition. The invention realizes the active deceleration braking operation under the deceleration condition, and provides stable and reliable contr