Our research interest is focused the interactive mechanisms and robotics, by which the motion and force of the devices are jointly synthesised based on their interaction with the user and the environment in order to meet clinical needs.

Some of our current and past research activities are listed below and in our Lab Youtube channel.

Recent Projects

A Fully-Decoupled Dexterous Robotic Instrument for Minimally Invasive Surgery

A novel robotic laparoscopic Instrument research video

This research developed a master-and-slave mechatronic system for a robotic laparoscopic instrument that has dual-side rotatable wrist and two-movable-jaw gripper. This new type of instruments in its kind has three degrees-of-freedom (DoF) including the pan rotation of the wrist, the grasping/dissecting of the gripper, and the roll rotation of the tool axis. Especially, the proposed instrument has a fully decoupled kinematics, i.e., the three DoFs are independently controlled by three actuations, respectively. Furthermore, the modularization of the proposed instrument was developed for quick docking on actuator module. A series of experiments have been performed for the built mechatronic system including the decoupled kinematics test and measurement, repeatability measurement, reproducibility measurement, force transmission ability test, and surgical manipulation test.

Kinematic Design of a Novel Dual-Orthogonal Remote Center-of-Motion Mechanism for Craniotomy

Craniotomy robotic manipulator research video

Craniotomy is an essential neurosurgical procedure to remove a section of patient’s skull. In order to do this, the surgical tools need to execute a one-DoF skull drilling motion along the tool axis followed by a two-DoF skull cutting motion. Particularly, this two-DoF skull cutting motion can be treated as a pivot rotation ideally. Therefore, the craniotomy tool motion is equivalent to a remote center-of-motion (RCM), which is renowned in surgical robotics. In this study, we proposed a novel hybrid RCM mechanism for robotic craniotomy. The mechanism is made of two orthogonal parallelogram-based linkages, which makes the two rotational DoFs decoupled. We also studied the position and differential kinematics of this new architecture and analyzed its potential singular configurations. We then set the local and global kinematic performance indices for obtaining the optimal mechanism dimensions. Finally, according to the optimization result, we created a mechanical prototype to verify the motion of the designed mechanism.

Innovative Design of an Automatic Acupoint Catgut-Embedding Instrument

Automatic acupoint catgut-embedding instrument research video

Acupoint catgut-embedding (ACE) therapy is a type of acupuncture surgery that combines concepts of traditional Chinese medicine with modern medical instruments. The therapy involves using a hypodermic needle and an acupuncture needle to embed 1-cm-long catgut segments in an acupoint, enabling the catgut to perform long-term stimulation of the acupoint and achieve the effects of acupuncture treatment. Each therapy process requires numerous repetitions of the same steps, and each needle set can only be used to embed one catgut segment. Additionally, doctors must perform this surgical procedure by hand; no automatic auxiliary instrument has been developed to date. To address these problems, we have developed an innovative first automatic ACE auxiliary instrument in the world. The instrument could assist doctors to complete the ACE steps. And it neither requires a battery or external electric power nor changes needles during therapy. The study first involved designing the mechanism and embodiment for the instrument, enabling it to perform one catgut-embedding procedure in only two steps with the repeated use of one needle set.

Reconfigurable Lower-Limb Rehabilitation Device with Switchable Hip/Knee-Only Exercise

Reconfigurable lower-limb rehabilitation device reseach video

In lower-limb rehabilitation, there is a specific group of patients that can perform voluntary muscle contraction and visible limb movement provided that the weight of his/her leg is fully supported by a physical therapist. In addition, this therapist is necessary in guiding the patient to switch between hip-only and knee-only motions for training specific muscles effectively. These clinic needs have motivated us to devise a novel reconfigurable gravity-balanced mechanism for tackling with these clinical demands without the help from therapists. The reconfigurable mechanism has two working modes, each leading the patient to do either hip-only or knee-only exercise. Based on the principle of static balancing, the gravitational effect of the mechanism and its payload (i.e., the weight of the patient’s leg) are completely eliminated in both configurations. A mechanical prototype of the design was built up and was tested on a healthy subject. By using electromyography (EMG), the myoelectric signals of two major muscles for the subject with/without wearing the device were measured and analyzed. This design for the first time demonstrates the design philosophy and applications by integrating the reconfigurability and static balancing into mechanisms.

A Novel Laparoscope Holder with Decoupled Positioning and Orientating Manipulation

Laparoscope holder with decoupled positioning and orientating motion research video

This research presents a novel mechanism concept of laparoscope holders used by minimally invasive surgery (MIS). Due to its special geometry, the laparoscope, which is held by the end-effector, can illustrate a remote center-of-motion (RCM) kinematics at the surgical incision point. The position of the RCM point is solely defined by a positioning arm of the holder, whereas the orientation and insertion length of the laparoscope are governed by a wrist mechanism as the end-effector of the positioning arm. Such an arrangement suggests a decoupled positioning and orientating manipulation for the holder, which is clinically helpful in laparoscopic MIS. We further make the overall mechanism statically balanced by using common linear springs. In other words, no electrical actuation or mechanical locks are required for making the laparoscope rest at any position and orientation. The design was anaylsed in commercial software MSC Adams and a prototype was built up for verification.

Multi-Backbone Continuum Robots: Kinematics, Design, and Experimental Measurement

Continuum dual-backbone robot research video

Continuum robots is a rapidly developed research topic in the field of robotics; however, the research activities in this field are still rare in Taiwan. Continuum robots are made of continuous materials such as fluid and wires whereby the motion of the robot end-effector is achieved via the deformation of the continuous materials. Thereby, the kinematics of the continuum robots is inherently coupled with the formation, geometries, and materials of the robot itself. It thus leads to a fact that the forward and inverse kinematics of general continuum robots are very difficult to deal with. This research to develop an efficient and reliable method, namely pseudo-rigid-body method, for solving the position kinematics of continuum robots, particularly of the multi-backbone continuum robots. Based on the success of the developed method, we are trying to employ 3-D printing technology to design and fabricate a multi-backbone continuum robot for making the robot being fully “continuous.” On the other hand, in order to validate the accuracy of our proposed kinematics method, we will use an optical inspection system to detect the geometry of the curved robot structure and compare measured data with the theoretical solutions. In summary, this project is an integration of multidisciplinary research fields including compliant mechanisms, continuum robots, optical inspection, and additive manufacturing.

Gravity Balancer Mechanisms with Variable Payload

Variable-payload gravity balancer research video

A gravity balancer can maintain its payload at any position without energy consumption ideally. This charming property has been successfully applied to several fields, e.g., industrial robots, rehabilitation devices, surgical instrumentation, aerospace, and electronic consumers. We are currently working on the innovation of new gravity balancer mechanisms that can automatically self-regulate for carrying different payload. We have come up with a single-degree-of-freedom gravity balancer that can deal with variable payload without requesting manual or other auxiliary adjustment. The proposed design is an integration of a spring-based statically-balanced mechanism and a spring adjusting mechanism. When different payloads are applied, the spring adjusting mechanism will act to regulate the spring installation points to suitable places such that mechanism and the (variable) payload remains constant balanced. A prototype was built up and successfully tested for the proposed concept.

Reconfigurable Cube Mechanisms

Reconfigurable cube mechanism research video

Reconfigurable cube mechanism (RCM) is a brainstorming puzzle made by eight connecting cubes. Owing to its special configuration characteristics, the mechanism can change its topological configuration during operation. Though there are lots of mechanism theories arisen from such a mechanism, the study on the RCM is extremely rare. Based on the theory of screw algebra, we studied the configuration characteristics and reconfiguration theory of the RCM. A matrix representation for representing the topological configuration of the RCM was proposed. By following screw theory, the configuration of the RCM is represented as a screw system matrix, whereby the mobility of the mechanism is investigated and the relative orientations and positions between the joints are recognized. Based on this, two new indices namely “structural isomorphism” and “configuration isomorphism” were devised. A computational approach for determining all possible configurations of the RCM from a given initial configuration was further put forward.