Types of Self Control Wheelchairs
Many people with disabilities use self-controlled wheelchairs to get around. These chairs are ideal for daily mobility and can easily climb up hills and other obstacles. They also have large rear flat free shock absorbent nylon tires.
The speed of translation of the wheelchair was calculated using a local potential field approach. Each feature vector was fed to a Gaussian encoder which output a discrete probabilistic spread. The accumulated evidence was then used to drive visual feedback, and an instruction was issued when the threshold was exceeded.
Wheelchairs with hand rims
The type of wheel a wheelchair is using can affect its ability to maneuver and navigate different terrains. Wheels with hand-rims can help reduce strain on the wrist and improve comfort for the user. Wheel rims for wheelchairs can be made of aluminum plastic, or steel and come in different sizes. They can be coated with vinyl or rubber for a better grip. Some come with ergonomic features, like being designed to conform to the user's closed grip and wide surfaces for all-hand contact. This lets them distribute pressure more evenly and prevents fingertip pressing.
A recent study revealed that rims for the hands that are flexible reduce the impact force and the flexors of the wrist and fingers during wheelchair propulsion. They also provide a larger gripping surface than standard tubular rims, permitting the user to exert less force, while still maintaining the stability and control of the push rim. These rims are available at most online retailers and DME providers.
The study found that 90% of the respondents were satisfied with the rims. However, it is important to note that this was a postal survey of those who had purchased the hand rims from Three Rivers Holdings and did not necessarily represent all wheelchair users suffering from SCI. The survey did not evaluate actual changes in pain or symptoms however, it was only a measure of whether individuals perceived an improvement.
Four different models are available: the large, medium and light. The light is a small-diameter round rim, whereas the medium and big are oval-shaped. The prime rims have a larger diameter and an ergonomically shaped gripping area. The rims can be mounted to the front wheel of the wheelchair in various colors. These include natural light tan and flashy greens, blues pinks, reds and jet black. These rims are quick-release, and are easily removed to clean or maintain. The rims are coated with a protective vinyl or rubber coating to keep hands from sliding and causing discomfort.
Wheelchairs with tongue drive
Researchers at Georgia Tech have developed a new system that lets users maneuver a wheelchair and control other digital devices by moving their tongues. It is comprised of a small magnetic tongue stud that transmits signals for movement to a headset with wireless sensors as well as mobile phones. The smartphone converts the signals into commands that control devices like a wheelchair. The prototype was tested by disabled people and spinal cord injury patients in clinical trials.
To assess the effectiveness of this system it was tested by a group of able-bodied people used it to complete tasks that assessed the speed of input and the accuracy. They completed tasks that were based on Fitts law, which included the use of a mouse and keyboard and maze navigation using both the TDS and a normal joystick. The prototype had a red emergency override button, and a friend accompanied the participants to press it when needed. The TDS performed equally as well as the standard joystick.
Another test compared the TDS to the sip-and puff system, which allows people with tetraplegia to control their electric wheelchairs by sucking or blowing air through a straw. The TDS completed tasks three times faster, and with greater accuracy than the sip-and puff system. The TDS can drive wheelchairs with greater precision than a person with Tetraplegia, who controls their chair using a joystick.
The TDS was able to determine tongue position with an accuracy of less than a millimeter. It also had camera technology that recorded the eye movements of a person to interpret and detect their movements. It also had security features in the software that inspected for valid inputs from users 20 times per second. Interface modules would automatically stop the wheelchair if they failed to receive an acceptable direction control signal from the user within 100 milliseconds.
The next step for the team is testing the TDS with people with severe disabilities. To conduct these tests they have partnered with The Shepherd Center which is a critical care hospital in Atlanta as well as the Christopher and Dana Reeve Foundation. They intend to improve the system's ability to adapt to lighting conditions in the ambient and to add additional camera systems, and enable repositioning for alternate seating positions.
Wheelchairs that have a joystick
A power wheelchair equipped with a joystick allows clients to control their mobility device without having to rely on their arms. It can be positioned in the center of the drive unit or either side. It also comes with a screen to display information to the user. Some screens are large and backlit to be more noticeable. Some screens are smaller and include symbols or images to aid the user. The joystick can be adjusted to suit different hand sizes, grips and the distance between the buttons.
As technology for power wheelchairs has advanced in recent years, clinicians have been able to design and create different driver controls that enable clients to reach their ongoing functional potential. These advances allow them to accomplish this in a manner that is comfortable for users.
For example, a standard joystick is an input device with a proportional function that uses the amount of deflection on its gimble to produce an output that grows when you push it. This is similar to how video game controllers or accelerator pedals for cars function. However this system requires excellent motor control, proprioception and finger strength to be used effectively.
A tongue drive system is a different type of control that uses the position of a user's mouth to determine the direction in which they should steer. A magnetic tongue stud sends this information to a headset which can execute up to six commands. It is suitable for people with tetraplegia and quadriplegia.
In comparison to the standard joystick, some alternative controls require less force and deflection in order to operate, which is useful for people with limited strength or finger movement. Others can even be operated using just one finger, making them perfect for those who are unable to use their hands at all or have minimal movement.
In addition, some control systems come with multiple profiles that can be customized for the needs of each user. This is particularly important for a novice user who might require changing the settings periodically in the event that they feel fatigued or have a flare-up of a disease. It can also be beneficial for an experienced user who wishes to change the parameters that are set up initially for a specific location or activity.
Wheelchairs that have a steering wheel
Self-propelled wheelchairs are designed to accommodate individuals who need to move themselves on flat surfaces and up small hills. They have large wheels on the rear for the user's grip to propel themselves. They also have hand rims, which allow the individual to utilize their upper body strength and mobility to move the wheelchair in either a forward or reverse direction. Self-propelled chairs are able to be fitted with a variety of accessories including seatbelts and drop-down armrests. They may also have legrests that can swing away. Certain models can also be transformed into Attendant Controlled Wheelchairs to help caregivers and family members drive and control the wheelchair for users that require additional assistance.
Three wearable sensors were affixed to the wheelchairs of participants in order to determine kinematic parameters. These sensors tracked movements for a period of a week. The distances measured by the wheels were determined using the gyroscopic sensor mounted on the frame and the one mounted on the wheels. To discern between straight forward movements and turns, the amount of time in which the velocity differences between the left and the right wheels were less than 0.05m/s was considered to be straight. The remaining segments were examined for turns, and the reconstructed wheeled paths were used to calculate the turning angles and radius.
This study included 14 participants. They were tested for accuracy in navigation and command latency. Utilizing an ecological field, they were tasked to navigate the wheelchair through four different ways. During transit wheelchair vs self propelled , sensors monitored the movement of the wheelchair along the entire distance. Each trial was repeated twice. After each trial, participants were asked to pick which direction the wheelchair to move in.
The results showed that the majority of participants were capable of completing the navigation tasks, though they were not always following the right directions. In the average, 47% of the turns were correctly completed. The remaining 23% either stopped right after the turn or wheeled into a second turning, or replaced with another straight motion. These results are similar to the results of previous studies.