Inhyuk Moon

Design of robotic hand with tendon-driven three fingers

This paper proposes a robotic hand with tendon-driven three fingers that consist of a thumb, an index, and a middle finger. Each finger is composed of a distal-middle phalange, a proximal phalange, and a metacarpal bone, which are jointed by one link between the distal-middle phalange and the metacarpal bone. The flexion of finger is actuated by a wire to serve as a tendon of finger. By pulling the wire using DC motor, the proximal phalange is actuated, and then the distal-middle phalange is actuated synchronously by the link mechanism. The finger extension is performed by a restoring spring. The designed hand with the tendon-driven fingers is executable various hand motions such as direction, grasping, scissors and rock postures. Experimental results show the designed robotic hand is applicable to hand prosthesis for amputees.

Grip force modeling of a tendon-driven prosthetic hand

This paper describes a grip force analysis of a tendon-driven prosthetic hand. The grip force is equivalent to tensile force transmitted by a link mechanism. Assuming that the tensile force to pull tendon is constant, the grip force according to the angle of MCP joint is analyzed by the statics. From experimental results, we show the maximum grip force of tendon-driven finger is 6N when the constant tensile force is 14N.

Biomechanical assessment of electric lifting chair for persons with disability

Electric lifting chair is a typical assistive product to aid for standing up and sitting down for persons with disability, and it is particularly useful for the elderly persons whose muscular system is weakened by degenerative joint disease. This paper describes a biomechanical assessment of electric lifting chair with hip-up function. In experiments we measured 3D motion data and electromyogram (EMG) on the femoral muscle when subject performs the standing motion on the predetermined seat height. The experimental results show that 15 degree of the hip-up angle is adequate for the hip-up function, and that the higher seat position is more effective to assist for standing up motion.

Design of biomimetic hand prosthesis with tendon-driven five fingers

This paper proposes a biomimetic hand prosthesis with tendon-driven five fingers. Each finger is composed of a distal-middle phalange, a proximal phalange and a metacarpal bone, which are connected to a link mechanism. The finger flexion is a resultant motion by pulling a wire to serve as a tendon, but the finger extension is performed by an elastic mechanism composed of a restoration spring. The designed hand prosthesis with tendon-driven five fingers has six degrees of freedom. But its total weight is merely 400.72g. The hand performs various hand functions such as the grasping and the hand postures. From experimental results, we show that the proposed hand prosthesis is applicable to amputees as a prosthetic hand.

Design of electric assist-standing chair for persons with disability design of electric chair to assist person with disability in stand up and sitting down

In this paper, we propose the assist chair for standing and sitting that composes the lifting mechanism for low seat. And We developed the entrapment sensing mechanism to consider the safety of lifting mechanism. And We designed the arm-rest to be controllable the 90[deg]. Lifting function and entrapment sensing mechanism are controlled assistive-control system. In experimental result show that the proposed lifting chair can sense the obstruction and adjustable the height of seat.

Design of seat mechanism for multi-posture-controllable wheelchair

This paper proposes a design of seat mechanism for a wheelchair to be controllable multi-postures such as standing, reclining, tilting and elevation. The seat is designed based on a link mechanism including linear actuator, and its kinematics analysis is also presented. To control the multi-postures, we design a PID-based position and speed controller, and a motion planner to generate an available next posture from the present status. Simulation results show that the designed seat mechanism and its planner are applicable to develop the multi-postures-controllable wheelchair.

Development of Surface Myoelectric Sensor for Myoelectric Hand Prosthesis

This paper proposes a compact-sized surface myoelectric sensor for myoelectric hand prosthesis. To fit the surface myoelectric sensor in the socket of the myoelectric hand prosthesis, the sensor should be a compact size. The surface myoelectric sensor is composed of a skin interface and a single processing circuit that are mounted on a single package. Since the skin interface has one reference and two input electrodes, and the reference electrode is located in middle of two input electrodes, we propose two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material used for the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering conduction velocity and median frequency of the myoelectric signal, we select the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22 mm. The signal processing circuit consists of a differential amplifier with band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value circuit. We evaluate the proposed sensor from the output characteristics according to the IED and the shape of the reference electrode. From the experimental results we show the surface myoelectric sensor with the 18mm IED and the bar-shaped reference electrode is suitable for the myoelectric hand prosthesis.

Modeling of Body Weight Support System for Person with Gait Disoder

This study designed a body weight support system controlling load on a patient during gait training. The designed system consisted of a tow device, elevation and rotation device, and load control device. The tow device tows a patient using an electric winch, and the elevation and rotation device elevates and rotates the body weight control system using a motor and bearings. And, the load control device controls load on a patient during gait training using elasticity force of two motors and spring. Load on a patient during gait training is measured by a load measurement sensor equipped in the load control system. The load control system controls load on a patient during gait training using the value measured by the load measurement sensor. This study modeled a body weight system to obtain design variables for motors and springs of the load control device by using a dynamics interpretation package, and made a control system to perform a control simulation of the body weight control system. Based on the simulation result, this study intended to design the proposed system as a system controlling load on a patient during gait training.

WEARABLE EXERCISE ROBOT WITH POWER ASSIST FUNCTION FOR WRIST REHABILITATION

In this paper a wearable exercise robot with power assist function for wrist rehabilitation is proposed. A force model for the wrist mechanism is presented, and its control system for active exercise and power assist function is designed based on the force model. In experiments the performances of active exercise and power assist function are verified. From the experimental results we show a possibility of the wearable exoskeleton robot in wrist rehabilitation and wrist motion.