• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.12
• /
• pp.1067-1076
• /
• 2016

This paper describes the development of a hybrid-powered wheelchair (HPW) for the elderly. The proposed HPW has novel mechanical and control features compared with conventional powered wheelchairs. An ergonomic back-braking mechanism was designed in order to stop the wheels easily. In terms of control features, the HPW remarkably reduces the muscle power required by combining various assistive functions, such as wheel torque assistance, friction/inertia compensation, gravity compensation, and the one-hand driving algorithm. For wheel torque assistance, strain gauges were attached to the hand-rim in order to measure the wheel torque applied by a human. Gyroscopes and an accelerometer were attached to the wheel and chair respectively for friction and inertia compensation. An inclinometer was attached for gravity compensation and the one-hand driving algorithm was included for patients who can only use one hand. The one-hand driving algorithm controls the angular velocity of the uncontrolled wheel by using a gyroscope and pressure sensors attached to the bottom of the seat. Finally, the performance of the proposed motion assisted algorithm was verified through various experiments.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.5
• /
• pp.527-534
• /
• 2015

This paper presents an integrated chassis control with electronic stability control (ESC) and active front steering (AFS) under lateral force constraint on AFS. The control yaw moment is calculated using a sliding mode control. The tire forces generated by ESC and AFS are determined using weighted pseudo-inverse based control allocation (WPCA) in order to generate the control yaw moment. On a low friction road, AFS is not effective when the lateral tire forces of front wheels are easily saturated. To solve problem, the lateral force of AFS is limited to its maximum and the braking of ESC is applied with WPCA. To evaluate the effectiveness of the proposed method, a simulation was performed on the vehicle simulation package, $CarSim^{(R)}$. From the simulation, it was verified that the proposed method could enhance the maneuverability and lateral stability if the lateral force of AFS exceeds its maximum.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.4
• /
• pp.165-174
• /
• 2004

This study is about a horizontal load test of buoyance anchor installed in the section where underground water level happens in the depth of 5m under the ground when the ground is excavated, because the section as a excavation section of high speed railway ${\bigcirc}{\bigcirc}$ station is near a rivers and because the section always has a reservoir of full water level on the left. Therefore, in this study we will appraise the long-term stability of the structure permanently being taken buoyance by the underground water level, through the spot test of the buoyance anchor installed in the section where underground water level happens. For that, Bar Type anchor is used, which can get enough pulling-out force by a method to resist buoyance by using friction force against the ground by high strength steel rod or steel wire. Anti-buoyance anchor is installed on the bottom slab of underground structure being taken horizontal force by the braking and accelerating of high speed train. And, It is aimed to analyze and grasp the review result of stability for the horizontal force that happens at the parking and stopping of high speed train, by executing horizontal load test for the grasping of the movements characteristic of buoyance anchor.