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This study generates the ranking of ten motivational factors of Vietnamese public sector employees and evaluates how the outside forces including economy, national culture and sectors effect the ranking as well as employees’ preference of motivation by using survey which asked the respondents to rank the factors and additional qualitative questions which provide respondents reasons for their ranking. The survey was conducted with 32 respondents from various public sector organizations. Our study shows the three context factors do influence the motivation of employees. It is concluded that economic situation makes more significant impact than other factors

A Cable-Driven Locomotion Interface provides a low inertia haptic interface and is used as a way of enabling the user to walk and interact with virtual surfaces. These surfaces generate Cartesian wrenches which must be optimized for each motorized reel in order to reproduce a haptic ensation in both feet. However, the use of wrench control requires a measure of the cable tensions applied to the moving platform. The latter measure may be inaccurate if it is based on sensors located near the reel. Moreover, friction hysteresis from the reel moving parts needs to be compensated for with an evaluation of low angular velocity of the motor shaft. Also, the pose of the platform is not known precisely due to cable sagging and mechanical deformation. This paper presents a non-ideal motorized reel design with its corresponding control strategy that aims at overcoming the aforementioned issues. A transfert function of the reel based on frequency responses in function of cable tension and cable length is presented with an optimal adaptative PIDF controller. Dynamic and static reel transparencies are evaluated experimentally with a cost function to optimize and with an analysis of friction respectively. Finally, a hybrid position/tension control is discussed with an analysis of the stability for achieving a complete functionality of the haptic platform.

Optimal tension control in parallel mechanisms for balancing wrench at the end‐effector introduces a complex model of the overall system. Moreover, actuator saturations such as motor current and angular velocity limits impose that a non‐linear system be controlled. Such a system is usually controlled sub‐optimally due to the complexity of its model. In haptic applications where transparency and stability are both critical parameters, optimal performance should be achieved. This paper introduces an enhanced FPID auto‐tuning based on Extremum Seeking‐Tuning (ES‐Tuning) which uses a different cost function to find the local optimal solution for haptic rendering and a correction on noise measurement for a high order complex system. The solution of this optimization gives a direct measure of the reel dynamic transparency evaluated by the proposed cost function.

A Cable-Driven Locomotion Interface employs two independent cable-driven haptic foot platforms constrained in six degrees of freedom (6-DOF). Its control system and its geometry are designed for performing a wide range of trajectories that could generate cable interferences. This paper presents and analyzes computational methods for determining which cable can be released from an active actuation state while allowing control in a minimal tension state, thereby ensuring that both platforms stay in a controllable workspace. One challaging task is to develop light and fast computational algorithms for hard real time processes included in haptic display applications. Seeing that releasing a cable from an active actuation state might generate discontinuities in tension values in the other cables, this paper proposes collision prediction schemes named Interference Estimated Time of Arrival in order to reduce or completely eliminate such discontinuities.