Motorized Wheelchair Mounting System Tyler Lark, Team Leader Richard Bamberg, Communications Dustin Gardner, BSAC Nick Harrison, BWIG BME 301 Department of Biomedical Engineering University of Wisconsin-Madison May 7, 2008 Client Andrea E. Johnson, CASC OTR/IT Waisman Center Advisor Thomas Yen, Ph.D. Department of Biomedical Engineering2Abstract A speech generation device is a critical tool for an individual whose speech is impeded by a disability. However, operation and handling of the device may be difficult for those confined to a wheelchair and have limited physical capabilities. In addition, the position required for use of the device may interfere with one’s ability to see or perform other functions. If the position causes a significant decrease in the user’s field of vision, the ability to drive or maneuver a wheelchair may be compromised. This semester, a motorized wheelchair mounting system was designed to give physically impaired users access to a speech generation device that stows safely out of the way. The design utilizes a mounting plate to provide support as well as protection for both the user and the mechanical components.3Table of Contents Page Abstract 2 Table of Contents 3 Problem Statement 4 Background Information 4-5 Current Devices 5-6 Design Constraints 6-7 Design 1: Shoulder Position 7-9 Design 2: Side Position 9-11 Design 3: Lap Position 11-12 Design Matrix 13-14 Final Design 14-17 Future Work 18-19 Conclusion 20 References 21 Appendix A: PDS 22-234Problem Statement Design a motorized wheelchair mounting system for a Vanguard Plus speech generating device. The client currently drives an electric wheelchair without the Vanguard mounted. However, with the device attached to his chair with the current mount, he cannot see to drive the wheelchair. Developing a mounting system that better meets his need would increase his independence by allowing him to use the Vanguard whenever necessary. We are interested to find out if a standard wheelchair mounting system could be adapted so that he is able to move his Vanguard into position to use it and then out of the way to store it and drive. Background Information Cerebral palsy (CP) is a non-progressive condition of brain damage that causes physical impairment, affecting body movement and posture. Seventy-five percent of all cases of CP are developed during pregnancy. While there is no cure at this time, therepy treatments continue making advancements and improve the quality of life for those living with the condition. (Bax et al, 2005; Jan, 2006) Our end-user, Will, is an 18-year-old male with cerebral palsy. His motor skills have been strongly affected and as a result, a wheelchair is currently used for Figure 1: Wheelchair with attached speech generation device.5mobility (Figure 1). In addition, his speech has been affected such that it is difficult to communicate with unfamiliar persons. However, recently he has made great progress in the tactile use of his left hand, which has enabled the use of a touch-activated speech generation device. The model he uses is a Vanguard Plus. The user is able to type sentences or select preprogrammed phrases that are spoken out loud by the device. The Vanguard also functions as a cell phone and is able to connect to and control a computer. In order to operate the device, it must be mounted on the left side of his wheelchair near his face so that he can easily see the display and comfortably touch the screen. When he uses his left hand to access the joystick, all his focus goes to the left. Current Devices At this time, there are no commercially available mounting devices sufficient to meet our user’s needs (DAESSY, 2004; Goodwin, 2007). Thus, a custom device is currently the only satisfactory solution. The mounting device he presently uses has been custom fabricated by his father. It consists of a vertical steel rod that attaches to the armrest of his wheelchair (Figure 2). Welded at the top of this rod is a horizontal steel cylinder. This horizontal piece serves as the interface between the mount and the Vanguard’s standard mounting bracket (Figure 3). While this Figure 2: The current mount attaches to the armrest of the wheelchair.6current mount does succeed in securing the device to the wheelchair, overall it is insufficient and does not meet user needs. With the device mounted in place as is, it severely hinders his field of vision and thus affects his ability to navigate and drive his wheelchair. As an additional problem with this mount, our end-user is unable to attach, position, or remove the device by himself at this time. Thus, in order to use the Vanguard, someone else is required to mount and position the device for him. Additionally, when he then wants to drive his wheelchair, someone else needs to remove the device and store it until the next use. Because of these problems, the speech generation device is currently only used during therapy sessions. Developing a custom motorized mounting system would increase the user’s independence by allowing him to always have access to the device and thus be able to effectively communicate with others whenever necessary. Design Constraints The Vanguard mount needs to be motorized because the user has limited strength and mobility. This restricts him from being able to manually move any type of non-motorized mount and does not allow him to attach or remove the Vanguard on his own. Ideally, the only user input needed will be the touch of one button to move the system from its position of typical use (eye level and to the left) to its final storage position, and then return with the same switch. Figure 3: Vanguard mounting bracket interface.7The final storage position of the device needs to be such that the user can quickly access it while in transit. Currently, because the Vanguard is not usually attached when he is moving in the wheelchair, he has no way of effectively communicating with people that do not deal with him on a regular basis. With the system accessible, he will be able contact his parents if his ride does not pick him up. If he needs to communicate with someone unfamiliar with his speech, such as a bus driver, he needs to have access to the Vanguard in order to do this.
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