• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1523-1531
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• 2011

Multi-axle driving vehicle are favored for military use in off road operations because of their high mobility on extreme terrains and obstacles. Especially, Military Vehicle needs an ability to driving on hills of 60% angle slope. This paper presents the improvement of the ability of hill climbing for 6WD/6WS vehicle through the optimal tire force distribution method. From the driver's commands, the desired longitudinal force, the desired lateral force, and the desired yaw moment were obtained for the hill climbing of vehicle using optimal tire force distribution method. These three values were distributed to each wheel as the torque based on optimal tire force distribution method using friction circle and cost function. To verify the performance of the proposed algorithm, the simulation is executed using TruckSim software. Two vehicles, the one the proposed algorithm is implemented and the another the tire's forces are equivalently distributed, are compared. At the hill slop, the ability to driving on hills is improved by using the optimum tire force distribution method.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.457-463
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• 2009

In this paper, a novel foot force distribution algorithm for hexapod walking robots is presented. The considered hexapod robot has fault-tolerant tripod gaits with a failed leg in locked-joint failure. The principle of the proposed algorithm is to minimize the slippage of the leg that determines the stability margin of the fault-tolerant gaits. The fault-tolerant tripod gait has a drawback that it has less stability margin than normal gaits. Considering this drawback, we use the feature that there are always three supporting legs, and by incorporating the theory of Zero-Interaction Force, we calculate the foot forces analytically without resort to any optimization technique. In a case study, the proposed algorithm is compared with a conventional foot force distribution method and its applicability is demonstrated.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.414-416
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• 1992

Stability analysis and load distribution problem of two coordinating robots using full dynamic model is studied in this paper. Dynamic models of two robots are combined with the position force control strategy and the Liapunov 2nd method is used for the proof of the stability. This analysis shows that the position and force control of two coordinating robot is always stable. Also, load distribution problem is mentioned with respect to the end-effector forces minimizing joint torques.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.57-58
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• 2007

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.72-79
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• 2008

In the redundant actuation system which has more actuators than a system's mobility, there are various method to determine actuated torques because those are not determined uniquely. This paper presents a torque distribution method using weighted-pseudoinverse to optimize the maximum torque of various actuated inputs of the redundant system. The various weighting factor of weighted-pseudoinverse is studied to reduce maximum actuated torque. This method is experimentally applied to 3RRR parallel robot, which shows that presented method can efficiently reduce the maximum actuated torque.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.731-738
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• 2013

This paper describes a fault-tolerant driving control strategy for an independent steer-by-wire system in sixwheel-drive/six-wheel-steering vehicles. An algorithm has been designed to realize vehicle maneuverability that is as close as possible to that of non-faulty vehicles by inducing high slip ratio of the wheel through a faulty steer-by-wire system in order to reduce the lateral tire force, which is resistant to the yaw motion. Considering the transition of the longitudinal tire force of a wheel with a faulty steer-by-wire component, the longitudinal tire forces are optimally distributed to the other wheels. Fault-tolerant driving performance has been investigated via computer simulations. Simulation studies show that the proposed algorithm can significantly improve the maneuverability of a vehicle with a faulty steer-by-wire system as compared to the optimal traction distribution method.

• Journal of Distribution Research
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• v.13 no.2
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• pp.1-27
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• 2008

In a power-asymmetry relationship like franchise system, a high dependent franchisee must often rely on its powerful partner. Therefore, in order to build up 'win-win' systems, therefore channel members should increase trust and commitment each other to enhance the relationship quality to sustain long-term cooperative relationships. First of all, to increase the relationship quality in franchise system, franchisor should increase franchisee's perception of the powerful franchisor's justice. The point of this research, I established basic hypotheses and comparative hypotheses to examine franchisor's behavior what franchisee expected which influences on franchisee's attitude and behavior in power - asymmetry relationship in franchise system. For the purpose of the empirical testing, managers of franchisee in the food service industry of Korea had been selected and analyzed, and major findings in this study as follow: First, the relational norm between franchisor and franchisee increased both distributive justice and procedural justice, especially relational norm had more effect on procedural justice than distributive justice. Second, distributive justice increased both economic commitment and social commitment while procedural justice just increased social commitment only but economic commitment. So, on the relational commitment, distributive justice was more important element than procedural justice. On the other hand, procedural justice had indirect effect on economic commitment through distributive and social commitment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.846-855
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• 1994

An effective stiffness, analogous to that of a wound spring, can be created by antagonistic redundant actuation of general closed-chain mechanisms. The qualitative and quantitative characteristics of the effective stiffness are investigated through a Four-bar mechanism, and a load distribution method is introduced which simultaneously guarantees the required system motion and the effective stiffness of the Four-bar mechanism. Furthermore, a simulation is performed to understand the inter-relationship among the effective stiffness, the Four-bar geometry, and the actuation effort. Based on this analysis, the Four-bar synthesis problem for effective stiffness generation is discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.162-167
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• 1991

The manipulability ellipsoid and the force ellipsoid for a single robot are extended to the case of a multi-robot system. The force ellipsoid is applied to solve the optimal load distribution for the multi-robot system. Two cases are considered in solving the optimal load distribution. In one case, there are no constraints on the joint torques, and the analytic solution ;a given. In the other case, the torque constraints are given in terms of the maximum power consumption, and the algorithm for the solution is proposed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.315-321
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• 2014

This paper presents an integrated chassis control system with fail safety using optimum yaw moment distribution for a vehicle with steer-by-wire and brake-by-wire devices. The proposed system has two-level structure: upper- and lower-level controllers. In the upper-level controller, the control yaw moment is computed with sliding mode control theory. In the lower-level controller, the control yaw moment is distributed into the tire forces of active front steering(AFS) and electronic stability control(ESC) with the weighted pseudo-inverse based control allocation(WPCA) method. By setting the variable weights in WPCA, it is possible to take the sensor/actuator failure into account. In this framework, it is necessary to optimize the variables weights in order to enhance the yaw moment distribution. For this purpose, simulation-based tuning is proposed. To show the effectiveness of the proposed method, simulations are conducted on a vehicle simulation package, CarSim.