Jianfei Luo

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.

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.

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.