Six-Axis F/T Fingertip Sensor (IEEE RAL 2020)

• To manipulate objects using a robot hand, it is important to measure the information of the various forces on the fingertips. In this research, a six-axis force/torque (F/T) fingertip sensor for a robot hand is introduced. The sensor was developed to provide the ability to measure six-axis F/T while remaining feasible for robot fingertip integration because of its miniaturization, light weight, and low cost (thanks to its simple manufacturing process). In particular, a novel highly sensitive shear force measurement method is proposed that uses the eccentricity of two cylinders. The designed six-axis F/T sensor was also fabricated. The developed sensor can be easily installed into the humansized fingertip of a robot.

Intrinsic Force Sensing Method for Human–Robot Interaction (IEEE T-RO 2021)

• Robotic manipulators require contact force sensing capabilities to sense the contact force between the manipulator and an object. Specifically, for humans and robots to coexist in the work environment, the robot must be able to detect an external force applied by a human. This study presents a new intrinsic force sensing method for robot manipulators that can obtain accurate information of the external force applied by a human during human–robot interaction. The method employs a robot cover, which is typically utilized in robot manipulators. Unlike conventional force sensing methods, a six-axis force/torque sensor is placed between the cover and the link of the robot manipulator. As a result, the proposed method provides information of the three-axis contact force applied to the cover surface and its contact location. Finally, an experiment is performed in which the robot successfully recognizes letters written on the cover, indicating a high level of contact force sensing performance. 

Sensorized Surgical Forceps for Robotic-Assisted Minimally Invasive Surgery (IEEE TIE 2018, previously in Robotory lab.)

• A novel force-sensing mechanism for surgical robotic systems is required for further innovation of roboticassisted minimally invasive surgery (RMIS). In this paper, novel sensorized surgical forceps are presented with fivedegree-of-freedom (5-DOF) force/torque (F/T) sensing capability: a grasping force, a 3-DOF manipulating force, and a rotational torque acting at the forceps. Two compact 3-DOF force sensors are integrated into the proximal region on two jaws of the forceps to measure 5-DOF F/T. The forceps also present important advantages for actual use in RMIS, such as miniaturization, compatible configuration to various shapes of surgical forceps, and packaged sensor electronics. In this study, the forceps are designed and manufactured at a low cost and are even disposable. To evaluate the forceps in a surgical robotic environment, the instrument is installed in a surgical robot, named S-Surge. In the environment, the 5-DOF F/T sensing capability is evaluated through comparison with reference sensors. 

A Surgical Palpation Probe With 6-Axis Force/Torque Sensing Capability for Minimally Invasive Surgery (previously in Robotory lab.)

• A novel surgical palpation probe installing a miniature 6-axis force/torque (F/T) sensor is presented for robot-assisted minimally invasive surgery. The 6-axis F/T sensor is developed by using the capacitive transduction principle and a novel capacitance sensing method. The sensor consists of only three parts, namely a sensing printed circuit board, a deformable part, and a base part. The simple configuration leads to simpler manufacturing and assembly processes in conjunction with high durability and low weight. In this study, a surgical instrument installed with a surgical palpation probe is implemented. The 6-axis F/T sensing capability of the probe has been experimentally validated by comparing it with a reference 6-axis F/T sensor. Finally, a vivo tissue palpation task is performed in a simulated surgical environment with an animal organ and a relatively hard simulated cancer buried under the surface of the organ. 

Six-Axis Force/Torque Sensor Calibration (current)

• Automatic Sensor Calibration System for a Six-Axis Force/Torque Sensor

Interactive portable surgical robotic system (previously in Robotory lab.)

• To achieve a compact and lightweight surgical robot with force-sensing capability, we propose a surgical robot called “S-surge,” which is developed for robot-assisted minimally invasive surgery, focusing mainly on itsmechanical design and force-sensing system. The robot consists of a 4-degree-of-freedom (DOF) surgical instrument and a 3-DOF remote center-of-motion manipulator. The manipulator is designed by adopting a double-parallelogram mechanism and spherical parallel mechanism to provide advantages such as compactness, simplicity, improved accuracy, and high stiffness. Kinematic analysis was performed in order to optimize workspace. The surgical instrument enables multiaxis force sensing including a three-axis pulling force and single-axis grasping force. In this study, it will be verified that it is feasible to carry the entire robot around thanks to its light weight (4.7 kg); therefore, allowing the robot to be applicable for telesurgery in remote areas. Finally, it will be explained how we experimented with the performance of the robot and conducted tissue manipulating task using the motion and force sensing capability of the robot in a simulated surgical setting.