Preserving Operator Intent Under Actuation Constraints: Teleoperation of Manipulators with Coupled Transmissions
Authors: Xuhan Miao, Zijin Han, Yutong Shen, Haidong Huang, Shanliushui Gao, Lei Zhang, Xiaocong Li, Chenguang Yang
Organizations: Beijing University of Technology, Beijing, China. · The Hong Kong Polytechnic University, Hong Kong, China. · Eastern Institute of Technology, Ningbo, China. · SynnoverAI. · Technical University of Munich, Munich, Germany. · University of Hamburg, Hamburg, Germany.
Teleoperation enables intuitive control of remote engineering robots for precision tasks. Existing direct joint-mapping methods have two limitations: independent motor saturation disrupts pitch-roll coordination in differential wrists, while fixed mappings struggle with abrupt tracking changes caused by gravitational loads and actuation constraints. We propose an actuator-constraint-aware leader-follower teleoperation method that jointly models leader gravity compensation, leader-follower joint mapping, and follower differential-wrist control. Specifically, we perform coordinated saturation in motor space according to the available gravity margin and integrate continuous angle unwrapping, feedback-state monitoring, and feasible-reference updates. This preserves the operator's motion direction, reduces coordination distortion, and suppresses recovery transients during saturation or brief communication failures. Real-robot experiments demonstrate smoother wrist trajectories and more continuous recovery than direct mapping.
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Fig. 2: The robotic arm is a serial multi-DOF biomimetic manipulator that adopts an anthropomorphic joint layout with multi-stage transmission integration. Its kinematic chain consists of an end-effector gripping mechanism, a wrist rotary joint, an elbow pitch joint, and a shoulder pitch joint connected in series. All actuation units are DM (Damiao) series servo motors, and independent or coupled motion of each degree of freedom is realized through gear transmission, synchronous timing-belt transmission, and differential coupling mechanisms. Specifically, the end-effector gripping mechanism is driven by a single DM4310 motor through a gear-meshing opposed transmission, enabling symmetric synchronous opening and closing of the two jaws with a compact form factor and low distal inertia. The wrist rotary joint employs a dual-DM4310 differential coupling drive, in which power is transmitted via two synchronous timing-belt stages to the lateral drive gears, and differential synthesis produces large-angle wrist rotation while reducing the radial dimension and optimizing the overall mass distribution. The elbow and shoulder joints serve as the primary motion and load-bearing joints, each equipped with a high-torque DM8009 servo motor. These joints adopt an electromechanically integrated mounting design, and the arm body uses a hollow truss structure, thereby reducing self-weight and improving dynamic performance while maintaining bending and torsional stiffness.
Fig. 3: To verify the effectiveness and robustness of our method, we evaluate it on four tasks: Insertion, Place, Follow, and Steer. The figure illustrates the successful execution procedure for each task.
Fig. 4: To validate the overall performance of our method, we recorded and compared in real time the indicators of the controller and the on-vehicle arm.
Fig. 5: Ablation study of gravity compensation. Joint position (top) and velocity (bottom) responses are shown for no compensation, Pitch 1 compensation, and Pitch 2 compensation. The shared legend identifies the six joint channels.
Robot teleoperation studies how people remotely control robots through interfaces, sensing, feedback, and autonomy, despite distance, delay, and embodiment gaps.
Department of Computer Science, New Jersey Institute of Technology, Newark, NJ, USA. · Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA. · Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA.
Department of Computer Science, New Jersey Institute of Technology, Newark, NJ, USA. · Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA.