signals for controlling various aspects of the control circuit 48 as discussed further below as depicted the user interface 60 provides a pair of tilt angle input keys 62 and 64 for selecting a desired orientation of reference plane 20 in the x and y axes respectively the numerical values of the preset desired orientation for the two axes x and y are displayed on display units 66 and 68 respectively and may be adjusted up or down by an adjuster key 70 it is to be appreciated that in another embodiment a numerical keypad may also serve the same function of inputting a desired x y orientation in one embodiment an enter key 72 is provided such that the desired x y orientation may first be determined and displayed in the display units 66 and 68 after selecting the enter key 72 the control system 46 will adjust the support platform 10 via cams 28 and 30 to bring the support platform to the preset desired orientation displayed in displayed unit 66 and 68 input keys 62 and 64 may illuminate a different color to indicate that the support platform 10 is at the desired orientation e g red to green via feedback control provided by sensors 42.