We investigate a collaborative-relay beamforming design for simultaneous wireless information and power transfer.A non-robust beamforming design that assumes availability of perfect channel state information (CSI) in the relay nodes is addressed.In practical scenarios,CSI errors are usually inevitable;therefore,a robust collaborativerelay beamforming design is proposed.By applying the bisection method and the semidefinite relaxation (SDR) technique,the non-convex optimization problems of both non-robust and robust beamforming designs can be solved.Moreover,the solution retued by the SDR technique may not always be rank-one;thus,an iterative sub-gradient method is presented to acquire the rank-one solution.Simulation results show that under an imperfect CSI case,the proposed robust beamforming design can obtain a better performance than the non-robust one.