Mandibular reconstruction is an extremely complex and high-risk surgery. The aim of the study was to integrate robotics technology into mandibular reconstruction surgery as it can reduce surgeons' workload and improve the accuracy and quality of the surgery. In this study, we first introduced a mandibular reconstruction surgery robotic system, which includes integrated surgery planning, an optical navigation system, and a robot-assisted operation. Second, we addressed novel mandibular reconstruction surgery that is aided by a multi-arm robot with an optical navigation system. Finally, we conducted an accuracy test, a skull model experiment, and an animal experiment to evaluate the robotic system. Experiments showed that the robot's mean placement error was 1.0205 mm, which was acceptable for clinical application. We will continue to study this point, however, and plan to reduce the error eventually to 1.00 mm. The robot ran smoothly and accurately. It was also able to perform fibular segment implantation, positioning, and auxiliary fixation during mandibular reconstruction surgery.

Operation in the area of Maxillofacial section is very difficult and risky due to its complicated and random anatomical structure. Therefore, to resolve these types of surgical issues, a multi-arm medical robot is designed. This paper presents a system able to perform complex maxillofacial surgeries using 6-DOF surgical manipulator and haptic device with force feedback capability. Force sensor is placed on manipulator end-effector and force feedback responses are felt on Haptic device. This proposed system improves surgical accuracy and removes surgeon's tension during tele-operation. The prototype of the whole system is designed and tests are conceded out under the surveillance of optical tracking system. The results demonstrate the system accuracy and reliability with force feedback competency.

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Aiming at the problem of how to store/release gait energy with high efficiency for the conventional unpowered lower extremity exoskeletons, an unpowered lower-limb exoskeleton is proposed. In the current study, the human motion model is established, and the change rule and recovery/utilization mechanism of gait energy are illustrated. The stiffness and metabolic cost of relevant muscles in lower extremity joints are obtained based on OpenSim software. The results show that stiffness of muscle is increased when muscle concentric contraction generates positive work, but it is reverse when muscle eccentric contraction generates negative work. Besides, metabolic cost of the soleus, gastrocnemius, and tibialis anterior decreased about 31.5%, 34.7%, and 40%, respectively. Metabolic cost of the rectus femoris, tensor fascia lata, and sartorius decreased about 36.3%, 7%, and 5%, respectively, and the total metabolic cost of body decreased about 15.5%, under the exoskeleton conditions. The results of this study can provide a theoretical basis for the optimal design of unpowered lower extremity exoskeleton.

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