摘要 |
<p>Automatic speed control system for a heavy vehicle including a system control unit (10) which regulates communication between a compressed air source (18) and an air actuated throttle (19); the system control unit (10) generates control signals over lines (15, 17) which are a function of a speed error signal and the position of the air actuated throttle (19) to regulate the compressed air source (18); the speed error signal is calculated as the difference between a commanded speed signal and an actual speed signal (AVS); to generate the control signals, the error signal and throttle position signal (THL) are operated on in the system control unit (10) by different lead-lag transfer functions, and these lead-lag terms are thereafter combined with a proportional speed error term to yield the desired control signals on lines (15, 17); according to the invention, the system control unit (10) limits the commanded speed signal to a set value when it exceeds a predetermined limit.</p> |