Aiming at the requirements of high-speed data transmission and low energy consumption in energy constrained Wireless Sensor Networks (WSNs), a mobile robot-based virtual V-BLAST cooperative MIMO transmission scheme and an efficient approximate maximum likelihood (ML) detection algorithm are proposed in this paper. Mobility of robot can reduce the communication distance between the sensor nodes, MIMO-based WSNs can use its diversity gain to overcome fading effects and can also use its multiplexing gain to increase the data transmission rate. As for the detection algorithm in mobile robot based virtual V-BLAST transmission scheme, combined with traditional decoding OSIC algorithm, the vectors needed to be detected in approximate ML algorithm are reduced. Mobile robot can receive with its own multi-antenna or using collaborative nodes around, and the energy efficiency analysis of the two cases are all discussed. Simulation results show that the proposed scheme effectively reduces network energy consumption, and the efficient approximate ML detection algorithm further improves energy-efficiency.