Materials handling vehicle estimating a speed of a movable assembly from a lift motor speed

摘要

A materials handling vehicle is provided comprising: a support structure including a fixed member; a movable assembly coupled to the support structure; a hydraulic system; and a control system. The support structure further comprises lift apparatus to effect movement of the movable assembly relative to the support structure fixed member. The lift apparatus includes at least one ram/cylinder assembly. The hydraulic system includes a motor, a pump coupled to the motor to supply a pressurized fluid to the at least one ram/cylinder assembly, and at least one electronically controlled valve associated with the at least one ram/cylinder assembly. The control structure may estimate a speed of the movable assembly from a speed of the motor and control the operation of the at least one valve using the estimated movable assembly speed.

主权项

1. A materials handling vehicle comprising:
a support structure including a fixed member; a movable assembly coupled to said support structure; said support structure further comprising lift apparatus to effect movement of said movable assembly relative to said support structure fixed member, said lift apparatus including at least one ram/cylinder assembly; a hydraulic system including a motor, a pump coupled to said motor to supply a pressurized fluid to said at least one ram/cylinder assembly, and at least one electronically controlled valve associated with said at least one ram/cylinder assembly; and control structure to estimate a speed of said movable assembly from a speed of said motor and to control the operation of said at least one valve using a comparison involving the estimated movable assembly speed and a determined speed and wherein the comparison does not involve use of an operator commanded speed.