A method, system, and non-transitory, computer-readable medium are provided for estimating a direction of gravity with respect to a robot. The method includes rotating a first joint. A first torque information of the first joint is recorded during rotation of the first joint. A second joint is then rotated. A second torque information of the second joint is recorded during rotation of the second joint. The direction of gravity is then estimated with respect to the robot based on the first torque information and the second torque information. The method provides an efficient way for determining the direction of gravity with respect to the robot.