POWER VEHICLE FOR DISABLED CHILDREN

This project is designed to assist children with varying levels of cognitive and physical disabilities. A Little Tykes Hummer H2 power vehicle is modified to allow children at the CIU facility to operate a vehicle normally inaccessible to them. It provides them with a means of transportation and allows them to explore their environment. It acts as a learning tool in training children with disabilities and is fun to operate.

The steering and motor control are adapted in this project to make them accessible to the children. Both functions are combined into a single handheld design. The vehicle is also equipped with a PIC microcontroller to process the steering and motor commands. A linear actuator is used to replace the mechanical steering system, it is electrically controlled and is capable of steering the vehicle.

MODES OF OPERATION:

The children at the facility have varying levels of disability. To accommodate these differences there are three modes of operation. For those with the greatest disability there is a single push button which simply moves the vehicle forward. For the children who are able to drive there is a four button array which allows driving in four directions, and for the most advanced there is a joystick which allows for complete freedom in all directions. Each mode of operation is built into inter-changeable panels.

MICROCONTROLLER:

The vehicle uses a PIC18F452 microprocessor and the programming was written using PIC Basic. The PIC is responsible for processing the user inputs and regulating motor and steering control.

SCHEMATIC:

Our overall design is pictured here. The pushbuttons and joystick are interchangeable and act as inputs to the PIC processor. The PIC receives these inputs and outputs the appropriate signal to the vehicle's motors and linear actuator. An amplifier scheme is introduced to provide the necessary input voltage to the linear actuator. The vehicle uses two 12V DC batteries to power these operations.

LINEAR ACTUATOR:

The linear actuator replaces the steering wheel and mechanical steering system. It receives +/- 5V inputs which rotate the actuator. It passes through the front axle of the vehicle and when it rotates it causes the vehicle to steer. This happens because the actuator is offset from the vehicle’s center. This process is illustrated in the figure to the right.

FINAL PRODUCT:

The vehicle has undergone considerable modifications. The original seat has been removed and replaced by a car seat with a safety harness. The PIC microcontroller is tucked away underneath the seat and all the wiring is concealed. A dash board of adjustable height has been constructed for the control panels. The original wheels have also been replaced to work with the linear actuator steering system.

Our thanks to our advisor Mr. Tim Wheeler for his guidance throughout the project.

For any questions or comments contact us at hsm118@psu.edu or tlj180@psu.edu

LETS GO STATE!!!