We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device...We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.展开更多
This paper presents the design and implementation of the embedded microcontrollers within a telescope control system. The design objectives of the overall system are to automatically find light emitting objects at nig...This paper presents the design and implementation of the embedded microcontrollers within a telescope control system. The design objectives of the overall system are to automatically find light emitting objects at night within a user specified area, to track a light emitting object for a user specified time given the initial position of the object, and to allow the user access to these functions through a graphical user interface. The embedded system is used to provide a communication link between the graphical user interface and system hardware, to provide angle data processing for a dual axis accelerometer, to provide data processing for an electronic compass, and to provide pulse outputs for the step and direction inputs of three stepper motor drives. This paper will describe the design, implementation, and results of each of these objectives.展开更多
Step motors, compared to other drive systems, are low-cost and easy to use devices. However, despite these undeniable advantages, they are characterized by some critical running conditions, due to the loss of synchron...Step motors, compared to other drive systems, are low-cost and easy to use devices. However, despite these undeniable advantages, they are characterized by some critical running conditions, due to the loss of synchronization between the stator＇s magnetic field and the rotor. In order to theoretically investigate such a behavior, several complex mathematical models have been developed, which require several parameters to be defined. For most step motors, such parameters cannot be easily drawn from their data-sheets; on the contrary, in this paper the authors refer to a simplified electro-mechanical model where the most of the parameters are known from data-sheets. The dependence between electrical and mechanical quantities can be investigated by an experimental point of view. At this aim, a specific novel test rig has been designed and developed for either static or dynamic characteristics measurement of small size step motors. In particular, the test rig allow to measure rotor＇s angular position, motor＇s torque, currents flowing in the motor＇s phases. The paper ends with the report of the results of several experimental tests, carried-out on a small-size motor in different running conditions, and with some preliminary remarks on the basis of the measures analysis.展开更多
基金Supported by t he National Natural Science Foundation of China （ No. 50435040） and the High Technology Research and Development Programme of China（ No. 2003AA420010）.
文摘We present the development of a novel prosthetic hand based on the underactuated mechanism. The aim is focused on increasing its dexterity while keeping the same dimension and weight of a traditional prosthetic device. The hybrid step motor is used as the actuator, which enables the finger to keep enough high contact torque on the grasped object with less energy consumption provided by the holding torque. The grasping force of the finger is estimated from the base joint torque, and the adoption of impedance control has provided compliance in the grasping. Also a parallel observer is used to switch over between the impedance control and the torque holding mode. The experimental results show the effectiveness of the design and control strategy.
文摘This paper presents the design and implementation of the embedded microcontrollers within a telescope control system. The design objectives of the overall system are to automatically find light emitting objects at night within a user specified area, to track a light emitting object for a user specified time given the initial position of the object, and to allow the user access to these functions through a graphical user interface. The embedded system is used to provide a communication link between the graphical user interface and system hardware, to provide angle data processing for a dual axis accelerometer, to provide data processing for an electronic compass, and to provide pulse outputs for the step and direction inputs of three stepper motor drives. This paper will describe the design, implementation, and results of each of these objectives.
文摘Step motors, compared to other drive systems, are low-cost and easy to use devices. However, despite these undeniable advantages, they are characterized by some critical running conditions, due to the loss of synchronization between the stator＇s magnetic field and the rotor. In order to theoretically investigate such a behavior, several complex mathematical models have been developed, which require several parameters to be defined. For most step motors, such parameters cannot be easily drawn from their data-sheets; on the contrary, in this paper the authors refer to a simplified electro-mechanical model where the most of the parameters are known from data-sheets. The dependence between electrical and mechanical quantities can be investigated by an experimental point of view. At this aim, a specific novel test rig has been designed and developed for either static or dynamic characteristics measurement of small size step motors. In particular, the test rig allow to measure rotor＇s angular position, motor＇s torque, currents flowing in the motor＇s phases. The paper ends with the report of the results of several experimental tests, carried-out on a small-size motor in different running conditions, and with some preliminary remarks on the basis of the measures analysis.
