gesture through wheelchair control (gtwc)
|Event Date/Time: Oct 15, 2009|
|Registration Date: Oct 15, 2009|
|Early Registration Date: Oct 15, 2009|
|Paper Submission Date: Oct 15, 2009|
SURESH JAJOO, PALLAVI P. SALUNKE & SHEETAL B. SHETI
Department of Electronics Engineering.,
Datta Meghe Engineering.College
Airoli,Navi Mumbai 400 708
This research develops a machines interface which has features of universal design and offers intuitive operations for complex task .We set the development of interface of electric wheelchair as a practical example, and proceed with this research. To improve quality of life for the elderly and disabled people, electric-powered wheelchairs (EPWs) have been rapidly deployed over the last 20 years. But up to now most of these electric powered wheelchairs are controlled by userâ€™s hands via joysticks and are very difficult for elderly and disabled users who have restricted limb movements. Therefore here we focus on the body motions which we humans have and try to realize a new type of interface which replaces conventional joysticks. In this work we refer gesture as basic form of nonverbal communication made with the hands. Naturalnessâ€™ of expression, non encumbered interaction intuitiveness are all good reasons to replace current interface technology example keyboard, mouse, joystick with more natural interfaces. Here common motions of our body are extracted and inputted to electric wheelchair interface these body motions are able to move the electric wheelchair in all directions. In this particular, this paper describes the design of prototype and results of basic research.
Gesture, Glove Circuit, Electric Power wheelchair, Tactical Microswitch, Microcontroller
Technology has changed the life of people around the world. It is something that keeps on improving which takes over some jobs that human used to do. In todayâ€™s fast pace world we are surrounded by technology to a very large extent but, this technology is limited to use of day to day devices controlled by electronic instruments like remote controlling television, lights, fans, music systems etc. mouse controlling computer. These always require an extra effort . So, instead we can opt for use of daily gestures like hand, head movements and also voice to drive these devices. Initially wheelchairs were used just as a fast and easy means to move disabled from one place to another, but this role changed as society progressed. Numerous inventions and improvements fashioned push rim for self-propulsion and slings for seat and backrests Then came the joystick controlled wheelchair .The joystick was pushed or pulled against 4 on/off switches which would cause the chair to jerk when it started, stopped or changed directions.
So the next big step in electric wheelchair development was the introduction of electronic circuitry and proportional control drive. An interface that enables an electric wheelchair to be operated by gestures such as head , hand , chin movements was developed.
This allowed the wheelchair rider to have greater control over the operation of the
chair Hand gesture includes a hand glove containing a transmitter circuit, which would transfer hand movements captured by the receiver circuits connected to the device.
In this particular we are designing electric powered wheelchair which is controlled by hand movement.
As per our need to control wheelchair, we use only two fingers of hand gloves. On these two fingers we place two photodiodes at upper side and two tactile micro switches below the finger as sensors. The signal coming from these gets encoded and sends to the transmitter to transmit.
On the other hand, at receiver side we get this signal with the help of receiver and send it to the decoder to decode it. Microcontroller is already been programmed for different code combinations, so that the decoded signal gets converted into appropriate movement of wheelchair with the help of relays and DC motor.
For an example:
For this particular case of wheelchair, when we bend fingers wheelchair will move in forward or reverse direction depending on which particular finger we bend. Similarly when we press the micro switch connected below the finger with the help of thumb, it rotate at either right or left angle depending upon the specific switch pressed.
The WGC is composed of three distinct subsystems: vehicle, glove and wireless interface. A block diagram describing these subsystems is shown in Figure 1 and Figure 2.
Fig 1. Wireless glove Block Diagram
Fig 2. Receiver section on wheelchair
The above fig. shows the block diagram of two sections transmitter as well as the receiver.
It consists of three blocks sensor, encoder, RF transmitter.
Sensor: A sensor is a physical device that detects, or senses, a signal or physical condition. Here photodiode acts as a sensor. As soon as it receives the signal it senses or detects it and gives it to the encoder.
Encoder: The encoder IC we use here is HT 12E. The encoder takes in incoming data along with some metadata (such as a signal that indicates whether the incoming data represents actual data or control characters) and produces an encoded value which is then transmitted on the link. The encoder IC we use here is HT 12E.It encodes the data and gives it to the RF transmitter.
RF Transmitter: The transmitter we use here is SM TX â€“ 433 AM / ASK TRANSMITTER. The encoded data is inputted to pin no 2 of the transmitter module .The transmitter transmits the encoded data which is then given to the receiver section
Receiver section consists of four blocks receiver , decoder , microcontroller, relay, motor.
We use SM RX â€“ 433 RECEIVER. The receiver receives the data from the transmitter and gives it to the decoder.
The decoder takes the values from the link and produces the original value, along with some information such as whether the incoming character contains any errors, and whether it represents a data or control character. Here we use decoder IC HT 12D .This decoder decodes the data i.e., it produces the original binary value and feeds it to the microcontroller.
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM)
The binary code received from the decoder is inputted to microcontroller
This code is in the form 1010, 0101, 1001and 0110 to which different data (directions) is programmed. As soon as the microcontroller receives one of these above codes it performs the operation assigned to it and as per its programming it gives signal to the relay driver circuit.
Relay driver circuit:
Single pole double throw relay is used which consists of two contacts NO and NC. A common terminal connects to either of two others. Including two for the coil, such a relay has five terminals in total. As soon as the relay driver circuit receives the signal the coils get energized and contact moves from normally closed to normally open and accordingly it drives the motors connected to it.
DC motor drives the wheelchair in forward , backwards , left, right direction accordingly.
1) HAND GLOVE
We use sleek, lightweight, stylish glove to hold all the sensors and circuitry used to detect different hand positions is as shown in figure: 3
In this circuit we used photo diode and tactile micro switch as sensor. To encode the signal coming from the sensors we use encoder IC (HT12F). A transmitter is used to transmit this encoded signal.
Initially, light continuously falls on photo diode the output of BJT is logic â€˜0â€™. As soon as we bend a figure light stops falling on photo diode at this time the output of BJT is logic â€˜1â€™.
Initially tactile micro switch is at logic â€˜0â€™ with the help of pull-up resistor. As soon as we press the switch port three of encoder logic â€˜1â€™. Port 10 to 13 of encoder IC (HT12E) are used as select lines on, which we receive signals from sensors. The code generated through hand gesture on these select lines is fed to transmitter via port 17. Thus transmitter receives the selected code and transmits it to the receiver circuit.
2) WIRELESS INTERFACE
The wheelchair section is portable unit so instead of using traditional power supply circuit (transformerïƒ rectifierïƒ regulator) we have directly made use of a 12 V, 4.5 Amp SMF (sealed maintenance free) batteries to power our circuit.
This section consists of receiver, decoder (HT12D), microcontroller, delay driver IC, relay, and DC motor.
The receiver receives the transmitted signal and this transmitted signal is fed to decoder (HT12D) at port 14. The decoded signal is fed to microcontroller through port 10 to 13.The signal coming from the microcontroller is used to drive the SPDT (single pole double throw) relay through drive IC ULN2803.
As we are using DC motor, each terminal of it is connected to two relays which can energize through coils. Initially contacts are connected to NC (normally closed) position. Depending upon the code generated respective coils gets energized and contact get moves from NC to NO (normally open position). The operation of motors depends upon following table.
MOTOR (L) MOTOR (R) WHEELCHAIR MOVEMENT
0 1 0 1 Forward
1 0 1 0 Reverse
0 1 1 0 Left turn
1 0 0 1 Right turn
Figure: Proposed Wheelchair
Complete look of wireless glove
The design for a Wireless Glove Utilizing innovative techniques, hand movements, translate user input allowing for a highly intuitive user interface.
A wireless transmission system mechanically detaches the operating from the commanding device. The design is successfully implemented and positioned for use in entertainment and scientific sectors.
The Wireless Glove (WG) was motivated by the need to create a highly intuitive control interface for a variety of applications. An additional goal of the WG is to create a cost-effective alternative to virtual reality gloves currently available. By use of various novel sensor configurations, the WG is capable of representing hand orientation in digital signals. This technology has far-reaching implications. To best demonstrate the range of the glove, we propose a highly specialized electric power wheelchair as the controlled subject. This technology has a wide range of applications, from scientific to entertainment. The WG can easily be implemented in scientific and military explorations of uncharted regions with a variety of remote-controlled devices, including terrestrial, nautical and airborne vehicles. Furthermore, our WG is an excellent marketable toy; the high degree of control achieved by the glove is sure to provide added enjoyment for any client.
As tools increase in complexity, so does the type of knowledge needed to support them. Complex modern machines require libraries of written technical manuals of collected information that has continually increased and improvedâ€” their designers, builders, maintainers, and users often require the mastery of decades of sophisticated general and specific training. The relationship of technology with society (culture) is generally characterized as synergistic, symbiotic, co-dependent, co-influential, and co-producing, i.e. technology and society depend heavily one upon the other.
Everybody wants security, safety, and comfort in every product they are going to use. In this case we mainly focus on disable peopleâ€™s comfort. People with severely disabilities must operate wheelchair with some input method. So here we put forward different methods by which wheelchair can be controlled easily and comfortably.
HEAD ORIENTED ELECTRIC WHEELCHAIR
This study aims to design a head oriented electric wheelchair for the severly spinal cord injured with normal head movement ability.
The configuration of this wheelchair interface control module with tilt sensors is shown in figure 1.
The proposed system replaces the original wheelchair joystick with two tilt sensor that are mounted into a headgear worn by pepole with sever disabilities. The tilt sensors are attached to the headgear. There is a touch switch attached to the headgear and closed to userâ€™s cheek. People with disabilities can puff their cheek to trigger the touch switch and perform emergency stop using the power brakes. The wheelchair controlled function include : forward, backword, left, right. The wheelchair interface circuit is controlled by tilt sensors composed of three major element: A. tilt sensor module; B. the signal processing module, and;C. a main controller(89C51 microprocessor).
CAPACITIVE INTERFACE FOR NAVIGATION OF ELECTRIC POWERED WHEELCHAIR
The design of capacitive interfaces developed on standard printed circuit boards, which allows persons with muscular weakness the ability to navigate an electric power wheelchair by small finger movements. The goal was to develop a high-quality and reliable capacitive-sensor interface that was easy to use, met ergonomic requirements and reduced the mobility requirements needed by that of a standard joystick user. Usability and acceptability criteria were also considered. An Assistive Device Platform was also developed to allow the sensors to interface to a wheelchair platform. The sensors were connected to the platform through an I2C connection. The platform can also accommodate for other sensors such as accelerometers and switch interfaces requiring digital interfaces such as SPI, parallel and serial connections thus accommodating for a wider range of motor disabilities. The platform has been tested by able and non-able bodied users.
THE ELECTRIC WHEELCHAIR CONTROLLED BY HUMAN BODY MOTION
The proposed wheelchair uses the pressure distribution on the seat back or seat face to measure the body motion and adopts it as interface input. Body pressure measurement system is adopted as the pressure sensor. To measure the body inclination, the inclinometer is attached to the subject. The subject leans their upper body in the direction of right-left and forward-back. The inclination of body and coordinates of centre of weight is measured simultaneously when a subject leans his upper body.
Fig. the position of the inclinometer
Fig. proposed system configuration
PC is main controller is mounted on the back seat. The pressure sensor, which measures the pressure distribution information, is attached to the seat back and sends information to the PC. PC gives instructions to the motor drive unit in accordance with pressure distribution information from the sensor.
CHIN OPERATED FORCE SENSING JOYSTICK CONTROLLED WHEELCHAIR
Chin operated force sensing joystick is one option for the people with quadriplegic to drive an electric power wheelchair. Comparing to the position chin operated joystick, it does not wheelchair user to move their head very quickly and accurately when using force sensing chin operated joystick.
Fig. The hardware of chin operated joystick
A design of small chin operated force sensing joystick consists of the joystick shaft, strain gauge signal circuit, analog circuit and digital circuit. The software consists of design of digital potentiometer control and digital signal processing. As shown in above figure joystick hardware consists of joystick shaft, strain gauge circuit, strain gauge signal amplifier circuit, microcontroller MH68H11, and digital to analog converting circuit.
SCOPE OF DEVELOPMENT:
As we are doing this at college level we design wheelchair operating by hand movement for function: forward, reverse, left, right turn for 300sq. feet range. By using same technology but highly precise components e.g. N bit encoder, decoder; high range transmitter, receiver; microcontroller with more no of ports and memory size; different sensors etc. we can add more functions and high range.
We can control speed of wheelchair, as well as we can add safety feature like it would stop automatically due to obstacles. We can also design multi controlling with the help of that same glove. In this case we can use different mode and each mode is dedicated for particular use e.g. Suppose we have two modes. Then mode 1 will control all wheelchair related operation and mode 2 will control music player related operation like increase or decrease volume, change the song etc. Instead of music player we can control TV, computer, fan and other home appliances also.
In this paper, we propose a gesture-based interface for connection and control of multiple devices in a ubiquitous environment. With simple selection and pointing gestures, users can easily control connections between multiple devices as well as manage information or data between them.
Wheelchair input control selection is very important for people with disabilities as the comfort and safety of the operation directly influences their quality of life and social ability. The results from this study revealed that the wireless hand glove commander developed in this study, although not absolutely superior to the joystick controlled method, should still provide better option for those people unsuited to traditional input devices.
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