This paper proposes a low-cost and lightweight wearable somatosensory controller for a robotic arm. The controller uses IMU sensors to capture the movements of the human arm and maps those movements to a remote robotic arm.On the wearable end, three IMUs are used to capture the seven degrees of freedom of the arm and send them to the remote end via a wireless network. The controller uses the space vector method to calculate the joint angles of the human arm and then performs mapping. This method effectively avoids the problems of large amount of calculation and singular points in inverse kinematics solution. It can be deployed on low-cost edge platforms. The simulation and experimental results prove the effectiveness of the controller in general scenarios.