Zhongcheng Wu

Characterization of fine motor development: Dynamic analysis of children’s drawing movements

In this study, we investigated childrens fine motor development by analyzing drawing trajectories, kinematics and kinetics. Straight lines drawing task and circles drawing task were performed by using a force sensitive tablet. Forty right-handed and Chinese mother-tongue students aged 6-12, attending classes from grade 1 to 5, were engaged in the experiment. Three spatial parameters, namely cumulative trace length, vector length of straight line and vertical diameter of circle were determined. Drawing duration, mean drawing velocity, and number of peaks in stroke velocity profile (NPV) were derived as kinematic parameters. Besides mean normal force, two kinetic indices were proposed: normalized force angle regulation (NFR) and variation of fine motor control (VFC) for circles drawing task. The maturation and automation of fine motor ability were reflected by increased drawing velocity, reduced drawing duration, NPV and NFR, with decreased VFC in circles drawing task. Grade and task main effects as well as significant correlations between age and parameters suggest that factors such as schooling, age and task should be considered in the assessment of fine motor skills. Compared with kinematic parameters, findings of NFR and VFC revealed that kinetics is another important perspective in the analysis of fine motor movement.

Research on calibration system error of 6-axis force/torque sensor integrated in humanoid robot foot

With the fast development of humanoid robot with high intelligence and accuracy, the improvement of comprehensive performance of 6-axis force/toque sensor(F/T sensor) has been constantly emphasized and further put forward to a higher demand. Except that a good proper mechanical design to guarantee the precision of the F/T sensor, the calibration quality is one of the most important factors of influencing the precision of F/T sensor too. The influencing factor of the precision of F/T sensor and system error source have been analysed from the view point of the calibration in this correspondence for the improvement of optimization design of sensor structure and calibration system in order to reduce or eliminate the error effects, which offers the theoretical foundation for improving the comprehensive performance and measurement accuracy of the F/T sensor.

Signal Processing and Application of Six-axis Force/Torque Sensor Integrated in Humanoid Robot Foot

Six-axis force/torque sensor (F/T sensor) that can detect three orthogonal forces and torques has been extensively adopted in humanoid robot foot for stable control. Due to the F/T sensors being seriously influenced by the electromagnetic interference from ankle generator, signal stability of F/T sensor is still one of the main influencing factors for accurately dynamical and stable control. Though the problem with influencing electromagnetic noise can be solved generally and partially by shielding of the sensor and wires, this traditional method will to some extend face implementation difficulty induced by special mounting space and application environment especially in humanoid robot ankle. Therefore, the research on the output signal stability and precision of the F/T sensors has still been one of the most essential subjects for humanoid robot dynamic equilibrium control. In this paper, some various signal processing methods have been adopted and analyzed comparatively with the aim at the output signal anti-interference processing of F/T sensors. And the filtering effect and its feasibility were verified experimentally in the dynamic walking motion of humanoid robot platform BHR-2.

DEVELOPMENT OF AN INTEGRATED PERCEPTUAL FOOT SYSTEM FOR HUMANOID ROBOTS

The realization of dynamic and stable walking anthropomorphically for humanoid robots to step on various kinds of uneven environments has long been considered as the research emphasis in the field of humanoid robot. The foot system constitutes the element which ensures the interaction between the humanoid robot and the environment. Apart from supporting the whole weight of robot and sensing the external forces exerted by the foot system on the ground during walk, perception of effective contact area (ECA) and foot postures are indispensably important information supports for various control schemes. This paper describes our research efforts aimed at an integrated perceptual foot (IPF) system which is designed by the conception derived from human foot motion mechanism. The IPF system possesses the capability to perceive the external forces/torques, ECA distribution, foot postures, zero moment point trajectory and topography conditions, etc. And the feasibility and validity of each sensor system in IPF system are experimentally tested on the humanoid robot platform BHR-2, which provide useful information support as possible to achieve some new and effective control schemes for humanoid robots.

Key Design of Control-Monitoring System of Steady High Magnetic Field Facility

Steady high magnetic field facility (SHMFF) is a basic tool for many scientific experiments and its control-monitoring system is the core part which supports experimental devices and subsystems for safe and reliable operation. The control-monitoring system of SHMFF with hierarchical structure is based on network-distributed measurement and control technology, including User Control System, Operator Control System, Central Database System, Operation Server, Magnet Control System, Web Service System, Timing System, etc. Reliable communication networks and communication interfaces based on the networks are designed for experimental devices and subsystems to exchange measurement and control data. S7-300/S7-400 PLC and industrial computers are used as the main controllers, and software system is designed based on WinCC with some interface and user programs written in C/C++ language. Additionally, an individual PLC system is configured for safety interlock and necessary identification is considered to experimental users in order to improve the reliability and security.

A novel f-pad for handwriting force information acquisition

This paper presents a novel pad for handwriting force information acquisition. The pad named F-Pad (force-pad) is capable of capturing both the dynamic handwriting information and the static trajectory of the writing pen. With the core part of the multi-dimension force/torque sensor, the F-Pad can capture the 3-D forces and 2-D torques directly. And with the specially designed structure, other dynamic and static information such as the velocities, accelerations, handwriting shape and slants can be got indirectly. Ordinary pens can be used to write on the pad and the pad provides a real-time visual feedback to gain a natural writing feeling. Basic experiments in which characters are written demonstrate the possibility of handwriting force information detection.

Development of real-time system for vibration detecting system

Vibration detecting system provides a monitor method for the equipment in normal work condition. A good detection system should get working statues of all components and transfer them to the terminal in time, so the system must have good real time performance. In this paper, we have realized a real-time Linux system for the self-designed vibration detecting system, coupled together with RTLinux patches. Based on the real-time kernel, we acquire and process the equipment vibration data in time, through CAN bus, RT-FIFOs and real-time threads. Results shows the system has good performance and meets the requirement.

Design and implementation of a standardized sensor network node based on virtual instrument and IEEE1451

Its the trend that sensor network become more standardized and unified as internet of things develops continuously. Aiming at resolving the problems arising from variety of sensors type and interface, this paper presents a design idea of a standardized sensor network node based on virtual instrument and IEEE 1451 standard, and expounds the realization of this sensor node. A concept of sensor node user program API is introduced to facilitate upper sensor network or host interacting with this standard sensor node. Test results show that this sensor network node could meet the practical application.

Design and Implementation of Safety Protection System for Water-Cooled Magnet of Steady High Magnetic Field Facility

Steady high magnetic field facility(SHMFF) provides the experimental environment of stable high magnetic field for scientific research. The core of SHMFF is a water-cooled magnet (WM) whose working condition is very rigorous. A kind of safety protection system (SPS) is needed to make sure that the WM could automatically enter safe state when working abnormally. This paper puts forward the strategy of protection for WM of SHMFF based on the way of detecting the resistance of WM’s coil, and explains the design and realization of SPS based on LabVIEW. Test results show that the SPS realized has good performance.