Medical collaborative robot

Medical robots play central role in computer integrated surgery. The robots are a hub where all the information about the patient is integrated to plan a personalized treatment plan for the patient and also a tool for precisely executing the planned treatment in a minimally invasive way. 

Up to now, the ole of the robots was passive, executing the commands from the operating surgeon.  In the era of Surgery 4.0, powered by artificial intelligence, the robots will serve more active role in the surgery, collaborating with the operating surgeon. For example, the robots can actively guide the surgeon to optimal surgical plane during dissection, or autonomously perform routine assistant task such as suction, retraction and simple suturing. Furthermore, the instruments of the robots will be slimmer to reduce invasiveness and be equipped with variable stiffness to simultaneously achieve high steerability and sufficient stiffness for tissue manipulation inside body. 

In CMR, we are currently performing researches on fundamental technologies for the medical collaborative robots for Surgery 4.0. Example projects are safe modular collaborative robot manipulator, learning and planning robot path using artificial intelligence, wrist mechanism for micro surgical instruments and continuum robots for follow the leader motion.

ESBS microsurgical robot

ESBS microsurgical robot

In endoscopic endonasal transsphenoidal surgery, for the treatment of deep brain tumors, such as craniopharyngiomas, an endoscope and surgical instruments are inserted through a nasal cavity into the lesion to remove the tumor. This has recently become the preferred technique because there is less likelihood of neural damage and a low complication rate. Manually controlled rigid surgical instruments are available for this procedure, but they provide limited dexterity and field of view.


Therefore, some areas remain inaccessible when these surgical instruments are used. To solve these problems, we propose a surgical robot system for endoscopic endonasal transsphenoidal surgery. We defined a target surgical space based on an analysis by a surgeon and designed surgical instruments to reach this target space. The system consists of two robot arms, end-effectors, surgical instruments, a master device, a control device, and a robot base.


The robot arm has an end-effector exhibiting two degrees of freedom (DOFs) and an inner channel, into which flexible surgical instruments are inserted. The flexible surgical instrument can reach the target space by steering the robot arm and end-effector. The outer diameter of the end-effector is 4 mm, and the diameter of the instrument channel, into which commercial surgical instruments can be integrated, is 2 mm.


We motorized the motion of the robot arms, end-effectors, and instruments and included motion capability with the necessary precision and developed a master device and control device to operate them. The surgical robot base is used to place the surgical robot before the operation and allow for manual operation. In a cadaver experiment, it was confirmed that the robot system can reach a larger area than is accessible with current surgical instruments, and it can support or remove tissues in the target surgical space.


Dr. Hujoon robot 

Epidural neuroplasty is a minimally invasive procedure of treating the herniated disc, in which a steerable catheter is inserted through the epidural space between the spine and the spinal cords and the drug injection or laser ablation is applied through the catheter to treat herniated discs. During the procedure, the physician must manually steer the catheter under X-ray guidance, leading to the problem of irradiation. 

In this project, Dr. Hujoon, a teleoperated robotic system for manipulating the endoscopic catheter for epidural neuroplasty is developed. The main technological outcome from the project are 

Dr. Hujoon robot 
  1. A teleoperated robotic endoscopic catheter mounted on a industrial robot arm for positioning. 

  2. Chip on the tip camera with optimized depth of field for endoscopic catheter 

  3. 6 degrees of freedom haptic master device 

  4. Navigation system for tracking 3D position of the catheter from 2D X-ray and 

  5. Virtual Reality simulator for the epidural neuroplasty training.

The feasibility of the system was verified in animal and cadaever experiments 


Modular robot (ModMan)

Nowadays, we are using several commercialized manipulator systems for manufacturing tasks or service tasks. In this existing industrial and service robot market, we are taking many kinds of advantages of robotics technology. But still, we have some limitations. The robot system commercialized by existing robot companies like DENSO, Yaskawa, has difficulty for task setting by usual line engineer. Also, at the same time, it means the task flexibility is low. And the price is still too high to be used in small and middle-size businesses. To overcome this limitation, in our project, the task adaptation was suggested as the primary strategy and goal. And, to achieve our goal, we choose modularization of robot HW and Self-reconfigurable SW as critical methods. Based on this approaching method, we hope to make a new modular robot market, And, the strategy of the modularity to solve existing limitations.

For the purpose, we have developed modular manipulator HW. This modular robot system is composed of a joint module, link module, gripper module, and 3D vision module. Also, we have developed a self-reconfigurable motion control engine, and the object recognition system is also be designed with a function of self-reconfigurable.


Wire-driven end effector device for frozen shoulder treatment

The cadaveric study using the wire-driven end effector device

The cadaveric study using the wire-driven end effector device

Several different flexible end effectors have been developed to solve the problem of approaching the lesion in a minimally invasive surgery. We developed a wire-driven end effector device to treat frozen shoulder. Since the device is for capsular release surgery, it has a suitable bend radius for the surgery.


It is a cylindrical cannula that can fit various surgical tools and can be sterilized after use. The end effector is made of an elastic material called PAI (polyamide-imide) with its outer diameter and total length being 4 and 19 mm. It is controlled by wires that are connected to a motor.

Through quantitative evaluation, we confirmed that the end effector can bend up to 90° in an upward or downward direction.

Through qualitative evaluation, we confirmed that the device can easier access all regions of the glenoid in a shoulder model than conventional electrocautery. An experiment on a cadaver followed, which allowed us to discuss the real-life performance, operation, and areas of improvement of the device with surgeons. From the experiments, we confirmed that our target region, the IGHL (inferior glenohumeral ligament), is within the reach of our device. The surgeon also evaluated that the control of the device caused no inconvenience.

The end effector inside of the cadaveric shoulder on the arthroscope view

The end effector inside of the cadaveric shoulder on the arthroscope view


Hyper-redundant manipulators for minimally invasive surgery

We are developing hyper-redundant manipulators with higher bending performance to use in minimally invasive surgery. Hyper-redundant manipulators are widely used in minimally invasive surgery because they offer the benefits of miniaturization and flexibility. However, when an external load acts on the hyper-redundant manipulator, their bending motion is disturbed, and their workspace decreases. We are developing a new bending mechanism to overcome these issues. The designed manipulator has a larger workspace and higher position accuracy. Simulation and experiments verified the performance of the new bending mechanism, and further in-vivo trials are underway. The new mechanism can be adapted to various medical fields such as transoral surgery and endoscopic interventions.