Materials handling vehicle having a control apparatus for determining an acceleration value

• US 9,421,963 B2
• Filed: 04/02/2014
• Issued: 08/23/2016
• Est. Priority Date: 02/05/2008
• Status: Active Grant

• Current Assignee: Crown Equipment Corporation
• Original Assignee: Crown Equipment Corporation
• Inventors: Wetterer, George Robert, Schloemer, James Francis, Crabill, Monty L., Jensen, Eric L.
• Primary Examiner(s): Do, Truc M
• Application Number:
  US14/243,384
• Publication Number:
  US 20140209406A1
• Time in Patent Office: 874 Days
• Field of Search: 701/41, 701/70, 701/50, 701/36, 701/69, 701/82, 701/73, 180/402, 180/446, 180/443, 180/444, 180/333, 180/334
• US Class Current: 1/1
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B66F 9/075 Constructional features or details
• CPC Class Codes: B66F 9/07509 Braking
• CPC Class Codes: B66F 9/07568 Steering arrangements
• CPC Class Codes: B66F 9/24 Electrical devices or systems

Abstract

A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Claims

1. A materials handling vehicle comprising:

a frame comprising an operator'"'"'s compartment;

wheels supported on said frame;

a traction motor coupled to one of said wheels to effect rotation of said one wheel;

a system associated with a steerable wheel to effect angular movement of said steerable wheel about a first axis, said system comprising a control handle capable of being moved by an operator to define a current desired angular position of said steerable wheel;

control apparatus varying a drive signal to said traction motor based on a steerable wheel error;

wherein said steerable wheel error is determined by comparing said current desired angular position of said steerable wheel to a current calculated actual position of said steerable wheel.

3. The materials handling vehicle as set out in claim 1, wherein said traction motor effects rotation of said one wheel about a generally horizontal second axis and said first axis is a generally vertical axis.

2. A materials handling vehicle comprising:

a frame comprising an operator'"'"'s compartment;

wheels supported on said frame;

a traction motor coupled to one of said wheels to effect rotation of said one wheel;

a system associated with said steerable wheel to effect angular movement of said steerable wheel about a first axis, said system comprising a control handle capable of being moved by an operator to define a desired angular position of said steerable wheel;

control apparatus varying a drive signal to said traction motor based on one of said desired angular position of said steerable wheel, a calculated actual position of said steerable wheel, a steerable wheel error, and a steer rate of said control handle, wherein said control apparatus determines a first traction motor speed limit based on said desired angular position of said steerable wheel, a second traction motor speed limit based on said calculated actual position of said steerable wheel, a third traction motor speed limit based on said steerable wheel error and a fourth traction motor speed limit based on said steer rate of said control handle, said control apparatus selects the smallest of the first, second, third and fourth traction motor speed limits and uses said smallest limit when generating said drive signal to said traction motor.