User's Waist Research Articles

Histogram Feature-Based Approach for Walking Distance Estimation Using a Waist-Mounted IMU

This paper presents a new method of walking distance estimation using an inertial measurement unit (IMU) placed on the user's waist. When the sensor is mounted on the waist, the walking steps can be easily detected. However, step length estimation is a challenging task. In this paper, a walking distance estimation method based on histogram features is proposed. The histogram features, including the uniform and logarithmic quantizations, are derived from each step segment of the acceleration norm data. Then, machine learning algorithms such as support vector regression (SVR), gaussian process regression (GPR), and linear regression (LR) are applied based on the histogram features to estimate the walking distance. Two experiments are conducted to evaluate the walking distance estimation accuracy, where test walking paths consist of a straight line corridor (80 m) and a rectangular path (about 1282 m). Experimental results show that the average absolute errors using the SVR model are 0.76% for straight line corridors and 1.14% for the rectangular paths. The proposed method is shown to outperform existing methods from comparison study.

A Shoulder Mechanism for Assisting Upper Arm Function with Distally Located Actuators.

This paper presents a new design for a shoulder assistive device based on a modified double parallelogram linkage (DPL). The DPL allows for active support of the arm motion in the sagittal plane, while enabling the use of a distally located motor that can be mounted around the user's waist to improve the weight distribution. The development of the DPL provides an unobtrusive mechanism for assisting the movement of the shoulder joint with a wide range of motion. This design contains three degrees-of-freedom (DOFs) and a rigid structure for supporting the arm. The modified DPL uses a cable-driven system to transfer the torque of the motor mounted on the user's back through the links to the arm. The proposed design assists with the flexion/extension of the arm, while allowing the adduction/abduction and internal/external rotations to be unconstrained. A kinematic analysis of the cable system and linkage interaction is presented, and a prototype is fabricated to verify the proposed concept.

Fabric texture design for boosting the performance of a knitted washable textile triboelectric nanogenerator as wearable power

The development of fibre/fabric-based triboelectric nanogenerators (TENGs) has received widespread attention because of their wearability and their ability to scavenge energy from human motion to power wearable functional electronics sustainably. However, the challenge of simultaneously providing characteristics that include high output power, continuous large-scale fabrication capability, easy incorporation with garment fabrication processes, washability and comfortable wear for the user still remains. Here, we propose a strategy for design and fabrication of TENG textiles with the merits of cloths that can be knitted from conductive silver-plated nylon threads using a commercially available knitting method. When these textiles are combined with a laminated composite fabric, free-standing mode TENG textiles are then realized. The performance of these TENG textiles could be enhanced by designing the knit fabric texture and the surface morphology of the laminated fabric. In addition, TENG textiles worn on the side of the user's waist have also been demonstrated to scavenge various types of energy from human motion and are capable of lighting light-emitting diodes (LEDs), powering a smart watch or acting as a motion sensor to provide constant monitoring of the movement signals of the human body. This work not only demonstrates the potential applications of these multifunctional self-powered textiles in wearable electronics, but also offers a promising strategy for exploring high performance TENG textile with industrialized large-scale manufacturing.

Safe Local Navigation for Visually Impaired Users With a Time-of-Flight and Haptic Feedback Device.

This paper presents ALVU (Array of Lidars and Vibrotactile Units), a contactless, intuitive, hands-free, and discreet wearable device that allows visually impaired users to detect low- and high-hanging obstacles, as well as physical boundaries in their immediate environment. The solution allows for safe local navigation in both confined and open spaces by enabling the user to distinguish free space from obstacles. The device presented is composed of two parts: a sensor belt and a haptic strap. The sensor belt is an array of time-of-flight distance sensors worn around the front of a user's waist, and the pulses of infrared light provide reliable and accurate measurements of the distances between the user and surrounding obstacles or surfaces. The haptic strap communicates the measured distances through an array of vibratory motors worn around the user's upper abdomen, providing haptic feedback. The linear vibration motors are combined with a point-loaded pretensioned applicator to transmit isolated vibrations to the user. We validated the device's capability in an extensive user study entailing 162 trials with 12 blind users. Users wearing the device successfully walked through hallways, avoided obstacles, and detected staircases.

Design and implementation of an intelligent belt system using accelerometer.

Activity monitor systems are increasing used recently. They are important for athletes and casual users to manage physical activity during daily exercises. In this paper, we use a triaxial accelerometer to design and implement an intelligent belt system, which can detect the user's step and flapping motion. In our system, a wearable intelligent belt is worn on the user's waist to collect activity acceleration signals. We present a step detection algorithm to detect real-time human step, which has high accuracy and low complexity. In our system, an Android App is developed to manage the intelligent belt. We also propose a protocol, which can guarantee data transmission between smartphones and wearable belt effectively and efficiently. In addition, when users flap the belt in emergency, the smartphone will receive alarm signal sending by the belt, and then notifies the emergency contact person, which can be really helpful for users in danger. Our experiment results show our system can detect physical activities with high accuracy (overall accuracy of our algorithm is above 95%) and has an effective alarm subsystem, which is significant for the practical use.

Identification of sit-to-stand and stand-to-sit transitions using a single inertial sensor.

In order to enhance the quality of life of people with mobility problems like Parkinson's disease or stroke patients, it is crucial to monitor and assess their daily life activities by characterizing basic movements like postural transitions, which is the main goal of this work. This paper presents a novel postural transition detection algorithm which is able to detect and identify Sit to Stand and Stand to Sit transitions with a Sensitivity of 88.2% and specificity of 98.6% by using a single sensor located at the user's waist. The algorithm has been tested with 31 healthy volunteers and an overall amount of 545 transitions. The proposed algorithm can be easily implemented in real-time system for on-line monitoring applications.

Developing an auto-tracking automated guided vehicle carrier using a wave-varied detecting method

Robots are widely used in modern industrial manufacturing, in households, in the entertainment sector, and in the security sector. In recent times, because of the increasing lifetime for old people, the concept of lifestyles of health and sustainability is prevailing. To facilitate a heavily loaded hand-carrier when aged people are travelling or working outside, an intelligent automated guided vehicle (AGV) is necessary. In this article, an intelligent and interactive AGV is developed. In order to develop the auto-tracking carrier for an AGV within an unlimited working space, a dynamic distance measuring system using the speed variation between a radio wave and an ultrasonic wave propagating in the air is adopted. The microchip PIC 18F452 is used as the control core. To facilitate the targeted functions, interactivity in conjunction with high quality sensors plays an essential role. By using a wireless transmitter (radio ray) and an ultrasonic transmitter on the user's waist angled towards the sensors at the front of the AGV, the distance between the user and the AGV can be calculated. To avoid colliding with a barrier, an ultrasonic transmitter is installed on both sides of the AGV. Subsequently, a controller based on fuzzy thinking will actuate the motor's motion enabling it to follow and dodge barriers. Consequently, a prototype AGV has been manufactured and successfully tested in the laboratory.

Waypoint navigation with a vibrotactile waist belt

Presenting waypoint navigation on a visual display is not suited for all situations. The present experiments investigate if it is feasible to present the navigation information on a tactile display. Important design issue of the display is how direction and distance information must be coded. Important usability issues are the resolution of the display and its usefulness in vibrating environments. In a pilot study with 12 pedestrians, different distance-coding schemes were compared. The schemes translated distance to vibration rhythm while the direction was translated into vibration location. The display consisted of eight tactors around the user's waist. The results show that mapping waypoint direction on the location of vibration is an effective coding scheme that requires no training, but that coding for distance does not improve performance compared to a control condition with no distance information. In Experiment 2, the usefulness of the tactile display was shown in two case studies with a helicopter and a fast boat.

THE MACHINE VISION BLIND GUIDE SYSTEM

The available guide tools of the orientation and mobility for a blind are the cane, guide dog and electronic guide devices. A cane is easy to detect the hindrance that is in front of the user but not for the hindrance above the user waist. That's why a cane user of a blind sometimes will be hit by the upper hindrance. Guide dog is a very powerful mobility guider but expensive and the training and living care for the dogs are difficult. Hence, guide dog is not popular in many countries. The electronic devices for blind guide tools such as laser cane; sonic glasses, sonic guide etc. can only detect a single point at a time and not for a whole view. In our system, a machine vision blind guide system is proposed. A CCD grabbed the image of front view and divided the image into nine blocks. Each block is calculated to get the distance message, which is multipoint data to guide the blind by the converted voice signal.

Submersible personal stereo system

A waterproof pouch to house a personal stereo cassette tape player or radio electrically connected by means of a retractile cable to a pair of waterproof headphones. The waterproof pouch has a closure enabling the pouch to repeatedly be hermetically sealed and reopened. A tubular belt loop is attached to one side of the pouch and secures a belt and buckle combination which fastens around the user's waist. A connector permanently and hermetically secures the electrical cable extending from the exterior to the interior of the pouch. The electrical cable in a coiled retractile form extends from the connector and splits into a Y-shape with both legs electrically attached to the waterproof headphones. Both waterproof headphones consist of a rigid disc with a waterproof earphone mounted on one side and a bracket mounted on the opposite side such that an elastic headband extends through the bracket. The headband is adjustable in length and secures the headphones to the user's head. Both waterproof earphones have pliable sleeves which form a hermetic seal with the user's ear canal to prevent water from entering the ear canal and disrupting the audio program heard by the user. A thin plastic membrane is positioned behind the diaphragm of the earphone to waterproof the earphone when not positioined in the user's canal. This invention enables the user to listen to a high fidelity stereo audio program while active in the water.