Hee-Don Lee

Mechanical Design of the Hanyang Exoskeleton Assistive Robot(HEXAR)

This study developed a lower extremity exoskeleton system to enhance lower body strength. In this paper, selected the degrees of freedom (DOF) which actuated based on analyzed human motion, and analyzed the human joint function to design the joint modules of the exoskeletal robot. To improve the efficiency of the exoskeleton robot, a mechanical structure was designed on the basis of a semi-anthropomorphic architecture. The Hanyang EXskeleton Assistive Robot (HEXAR) has seven degrees of freedom per leg, two of which are powered by an electrical motor. Appropriately sized motors and gearing are selected, and put through a thorough power analysis. quasi-passive mechanisms were designed with compliance material for supporting the weight of external loads in the stance phase and absorbing/releasing the energy. This paper discusses design criteria considered in mechanical design for HEXAR.

Design of an Under-Actuated Exoskeleton System for Walking Assist While Load Carrying

This study proposes an under-actuated wearable exoskeleton system to carry a heavy load. To synchronize that system with a user, a feasible modular-type wearable system and its corresponding sensor systems are proposed. The design process of the modular-type exoskeleton for lower extremities is presented based on the considered requirements. To operate the system with the user, human walking analysis and intention signal acquisition methods for actuating the proposed system are developed. In particular, a sensing data estimation strategy is applied to synchronize the exoskeleton system with a user correctly. Finally, several experiments were performed to evaluate the performance of the proposed exoskeleton system by measuring the electromyography signal of the wearers muscles while walking on level ground and climbing up stairs with 20- to 40-kg loads, respectively.

Development of human-robot interfacing method for assistive wearable robot of the human upper extremities

We suggest a human-robot interfacing method of a wearable robot for assistive human upper extremities. It connects the human and the robot with the multi-axis load-cell, and it measures the relative force between the human and the robot. The control system calculates the trajectory of end-effector using this force signal. In this paper, we verify the performance of proposed system through the motion of elbow E/F (extension/flexion), the shoulder E/F, and the shoulder Ab/Ad(abduction/adduction). We generated the command signal using the human-robot interfacing method so that a user would be able to operate the wearable robot of 6-DOF. And, we performed subsequent capability and force assistance experiments for performance verification of the proposed this method.

Development of an underactuated exoskeleton for effective walking and load-carrying assist

Abstract This study proposed and developed an underactuated exoskeleton to support external load-carrying and partial assist for leg motion with level walking and ascending of slopes and stairs, which require positive energy generation. A strategy for active and passive joint combination are implemented on the underactuated exoskeleton, along with a quasi-passive mechanism to assist with vertical weight support and gait propulsion while minimizing hindrance to the wearer’s free motion. Further, muscle circumference sensors are directly matched with the active joint system, and insole sensors are applied to efficiently detect the wearer’s motion intension. Through experiments with the developed exoskeleton system, the considered performances were verified by analyzing the electromyography data from the rectus fremoris and gastrocnemius muscles while walking and ascending stairs. The developed underactuated exoskeleton can assist healthy people’s load-carrying and facilitate efficient ascension by utilizing the structural body weight support, leg swing, and lifting motion assist through motorized knee joints only. This kind of active joint minimization approach could be particularly helpful in field applications that require independent power sources such as batteries.

Development of Command Signal Generating Method for Assistive Wearable Robot of the Human Upper Extremity

This paper proposes command signal generating method for a wearable robot using the force as the input signal. The basic concept of this system pursues the combination of the natural and sophisticated intelligence of human with the powerful motion capability of the robot. We define a task for the command signal generation to operate with the human body simultaneously, paying attention to comfort and ease of wear. In this study, we suggest a basic exoskeleton experimental system to evaluate a HRI(Human Robot Interface), selecting interfaces of arm braces on both wrists and a weight harness on the torso to connect the robot and human. We develop the HRI to provide a command for the robot motion. It connects between the human and the robot with the multi-axis load-cell, and it measures the relative force between the human and the robot. The control system calculates the trajectory of end-effector using this force signal. In this paper, we verify the performance of proposed system through the motion of elbow E/F(Extension/Flexion), the shoulder E/F and the shoulder Ab/Ad (Abduction/Adduction).This paper proposes command signal generating method for a wearable robot using the force as the input signal. The basic concept of this system pursues the combination of the natural and sophisticated intelligence of human with the powerful motion capability of the robot. We define a task for the command signal generation to operate with the human body simultaneously, paying attention to comfort and ease of wear. In this study, we suggest a basic exoskeleton experimental system to evaluate a HRI(Human Robot Interface), selecting interfaces of arm braces on both wrists and a weight harness on the torso to connect the robot and human. We develop the HRI to provide a command for the robot motion. It connects between the human and the robot with the multi-axis load-cell, and it measures the relative force between the human and the robot. The control system calculates the trajectory of end-effector using this force signal. In this paper, we verify the performance of proposed system through the motion of elbow E/F(Extension/Flexion), the shoulder ElF and the shoulder Ab/Ad (Abduction! Adduction).

Development of a lower extremity Exoskeleton Robot with a quasi-anthropomorphic design approach for load carriage

This study developed the Hanyang Exoskeleton Assistive Robot (HEXAR)-CR50 aimed at improving muscle strength of the wearer while transporting a load. The developed exoskeleton robot HEXAR-CR50 has 7 degrees of freedom (DOF) for one foot, 3-DOF for the hip joints, 1-DOF for the knee joints, and 3-DOF for the ankle joints. Through functional analysis of each human joint, two DOFs were composed of active joints using an electric motor developed in an under-actuated form with heightened efficiency. The rest of the DOFs were composed of passive or quasi-passive joints to imitate human joints. The control of the exoskeleton robot was based on the physical human-robot interaction. In order to verify the performance of the developed HEXAR-CR50, muscle activity was measured using electromyography, vGRF was measured using F-Scan sensor. The experimental results showed that %MVIC was reduced against the external load applied, while GRF had a decrement rate, compared with the external load when the exoskeleton was worn, which verified the performance in accordance with the development objective of load carrying. A muscle strength augment effect from the developed wearable robot was verified.

Design and Feasibility Verification of a Knee Assistive Exoskeleton System for Construction Workers

Robotic-powered exoskeletons and body joint-adapted assistive units are currently under development for the enhancement of human locomotor performance in the military, in industries, and in patients and the elderly with mobility impairments [1]. They free people from much labor and the burdens of many kinds of manual work. For example, when it comes to automation in the industrial field, factory automation has made good progress. Operators (humans) can be included in a conventional manufacturing process with respect to a formal production line and uniform working conditions. Automation outside the production line, however, especially in common manufacturing stages, has several limitations and difficulties in adapting to actual conditions because the industrial field has but a small part in the process due to its operating characteristics. There have been many approaches to the reduction of labor that do not only fully assist but also partly aid workers, such as in the use of extremely heavy payload-oriented construction equipment, which are manipulated by humans. Manual or semi-automatic machine tools are mostly used in contemporary industries. In particular, without manpower, especially without the manipulability and mobility of the upper and lower human limbs, full automation will be incompatible with today’s technologies [2]. Exoskeletons have strong advantages given their unique features such as their outstanding physical performance, exceeding that of humans, and their agility, which is utilized by operators’ nerve systems. As a result, attempts to adopt exoskeletons in the industrial field, especially at construction sites, indicate the use of feasible approaches to factory automation. The strategy and support method for exoskeletons that amplify human muscle power can be divided into four main categories: (1) exoskeletons that totally alternate with both the upper and lower parts of the muscle power system, (2) assist the all extremities not alternate (here, assist means the human share the load with the exoskeleton and alternate means the human just input operation command using his own motion into exoskeleton system and it totally handles the load), (3) alternate with the part of all extremities (4) assist the part of all extremities of muscle power system. The first type of exoskeleton which alternates with the entire muscle power still has many limitations, as with its size and electric power supply. Due to these constraints, exoskeletons are usually bulky and cannot freely move out of the range of the power source line. One of the representative studies of the second type which assists the whole body is the HAL series.