## 1 Introduction  
With significant advances in the last decades, robotic teleoperation has gained widespread acceptance and has become one of the most attractive topics due to its potential in dealing with those human-unfriendly, harmful, and unreachable scenarios [1]. Many promising results have been achieved in many challenging telemanipulation tasks, such as robot-assisted surgery [2], space exploration [3], disaster response [4; 5], underwater occasions [6], and micromanipulation [7]. Generally, a robotic teleoperation system is composed of the human operator, master devices, communication channels, slave robots, and the environment [8]. During the teleoperation, the human operator directly controls the movement of the master device, which is physically connected with the human operator. The control command is generated from the master device and then sent to the slave robot to perform specific tasks. The interaction force between the slave robot and the environment is sent back to the master device while the position and orientation of the slave robot would be acquired via visual perception or directly observed by human eyes. Thus, the bimanual telemanipulation can be seen as such a framework where each human system interface is controlled by one human hand under teleoperation environments [9]. Corresponding to the robotic manipulation system, the robotic teleoperation is divided into two categories: the teleoperation of the robotic arm and the teleoperation of the robotic gripper. Various haptic devices and sensors have been introduced for the robotic teleoperation. Based on a Leap Motion Controller and a sensorized glove, [PERSON] and [PERSON] proposed a sensor fusion technique for human finger tracking and applied it in the teleoperation of a three-fingered soft robotic gripper [10]. [PERSON] et al. developed a hybrid telemanipulation system via a 3D printed soft robotic gripper and a soft fabric-based haptic glove [11]. Four sensors were used to match with the four-fingered soft robotic gripper in the telemanipulation system. [PERSON] et al. presented a multilateral teleoperation system with two haptic devices on the master side and a four-fingered robotic gripper on the slave side [12]. The type-2 fuzzy model was used to investigate the system dynamics. Furthermore, [PERSON] and [PERSON] suggested an integrated vision system by using a Three Gears and a Leap Motion Controller [13]. Hand gestures were used to control a three-fingered dexterous gripper. Besides the robotic gripper, [PERSON] et al. put forward a wearable arm exoskeleton-based bilateral robot teleoperation system [14]. A modified sensoric arm exoskeleton was used as a haptic master device to control a 7 DoFs (degrees of freedom) Kuka robot. [PERSON] et al. studied the human-robot interaction in robot teleoperation [15]. Human body motion and hand state were captured by a Kinect v2 to control two robotic arms. [PERSON] et al. proposed a neural network enhanced robotic teleoperation system with guaranteed performance [16]. A Kinect sensor was used to detect the obstacles around the robotic arm while a Geomagic Touch was adopted as the master device to control the Baxter arm. Rather than the single teleoperation of the robotic arm or robotic gripper, some efforts have been made into the hybrid teleoperation with both the arm and gripper. [PERSON] et al. developed the teleoperation of a concentric tube robot via hand gesture visual tracking [17]. [PERSON] et al. investigated the grasping of rigid objects with a unilateral robot-assisted minimally invasive surgery system [18]. A haptic device of Novint Falcon was used in the teleoperation of the surgical robots. [PERSON] et al. proposed a wearable haptic enhanced robotic teleoperation system for telemanipulation tasks in cluttered environments [19]. A Pisa/IIT SoftHand and a robotic arm were equipped as the slave system. Two wearable vibrotactile armbands were worn on the upper arm and forearm to perceive feedback about collisions on the robotic arm and hand.