| 摘要 |
<p>PURPOSE:To ensure current limitation in a steering stopper zone and the preven tion of current limitation in a normal zone by limiting motor current when a steering condition is kept in a steady state, and a motor current value or a motor drive duty ratio is equal to or more than the set value. CONSTITUTION:CPU 4 computes a motor current indication value (c) and the direction thereof from a handle torque signal (a) and speed signal (b). Upon receipt of the values so computed, a motor 18 begins to turn. Then, CPU 4 detects voltage VM between motor terminals and makes judgement about a steering condition. When the steering condition is in a steady state, judgement is further made as to whether motor current I exceeds the set value ISET. When I is equal to or more than ISET, CPU 4 judges that an overload condition is taking place and limits the current. According to the aforesaid construction, current limitation in a steering step zone and the prevention of current limitation in a normal zone can be properly performed, thereby preventing a heavy steering state in the normal zone.</p> |
