| 摘要 |
PURPOSE:To confine the influence of trouble in a switch to the minimum as well as to make improvements in safety, by constituting it so as to make a cancel signal for constant-speed driving control generable even at the time of trouble in the stop lamp switch operated in response to pedal operation on a brake. CONSTITUTION:During constant-speed driving control under a normal acting state in a central processing unit 11, if a brake is operated, in both stop lamp switches A and B, the cancel signal generating side A comes on and the release valve control side B is off, whereby a release signal (a) of an H level is outputted out of the CPU 11, and a release valve 21 is opened. At this time, such trouble that the switch A fails to come on even if the brake is operated happens, detection output of a comparator CMP inputting the release signal (a) being left as an L level intact comes to a second cancel signal C2 by way of an OR gate G3, and inputted into the CPU 11 by way of an inverter INV, therefore the CPU 11 comes to command the constant-speed driving control interruption even if there is no first cancel signal C1.
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