Distributed control system for forklift

• US 20040249538A1
• Filed: 05/28/2004
• Published: 12/09/2004
• Est. Priority Date: 05/29/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Nichiyu Forklift Co., Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd., Nissan Motor Co., Ltd.
• Inventors: Saito, Toru, Osaki, Kuniharu
• Granted Patent: US 7,366,600 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: B66F 9/24 Electrical devices or systems

Abstract

A distributed control system is composed of a plurality of controllers mounted on a forklift, and a network providing connections between or among said plurality of controllers within said forklift. A first controller out of said plurality of controllers is configured to control a function in response to an interfacing signal received from a second controller out of said plurality of controllers. When not receiving said interfacing signal during a predetermined period, the first controller controls said function using data stored in said first controller in place of said interfacing signal.

Claims

1. A distributed control system comprising:

a plurality of controllers mounted on a forklift, each controlling an associated function of said forklift;

a network providing connections between or among said plurality of controllers within said forklift,

wherein a first controller out of said plurality of controllers is configured to control said function associated therewith in response to an interfacing signal received from a second controller out of said plurality of controllers, and

wherein said first controller controls said function associated therewith using data stored in said first controller in place of said interfacing signal when not receiving said interfacing signal during a predetermined period.

2. The distributed control system according to claim 1, further comprising a display unit connected to said network,

wherein said forklift includes internal combustion engine,

wherein one of said first and second controllers is an engine controller, while another of said first and second controllers is a vehicle controller,

wherein said vehicle controller generates a plurality of forklift components control signals for controlling forklift components in response to forklift component signals received from forklift components within said forklift,

wherein said engine controller generates a plurality of engine control signals for controlling said engine in response to a plurality of engine signals received from engine components within said engine, and

wherein said display unit displays at least one of said plurality of forklift component signals, said plurality of forklift component control signals, said plurality of engine signals, and said plurality of engine control signals.

3. The distributed control system according to claim 2, wherein said vehicle controller outputs at least one selected forklift component signal out of said forklift component signals, and said forklift components control signals to provide for said engine controller,

wherein said engine controller is configured to receive said selected forklift component signal as said interfacing signal, and to generate at least one of said plurality of said engine control signals in response to said selected forklift component signal.

4. The distributed control system according to claim 3, wherein said engine controller uses stored data therein in place of said selected forklift component signal, and generates a first alarm signal, when not receiving said selected forklift component signal during a predetermined period, and

wherein said display unit displays a first alarm informing that said engine controller does not receive said selected forklift component signal in response to said first alarm signal.

5. The distributed control system according to claim 3, wherein said at least one selected forklift component signal includes a vehicle speed signal indicative of a speed of said forklift, and a vehicle speed limit signal indicative of a speed limit of said forklift,

wherein said plurality of said engine signals includes an accelerator sensor signal indicative of a state of an accelerator pedal of said forklift,

wherein said plurality of said engine control signal includes a fuel injection rate signal indicative of an injection rate of said engines,

wherein said engine controller generates said fuel injection rate signal in response to said vehicle speed signal, said vehicle speed limit signal, and said fuel injection rate signal.

6. The distributed control signal according to claim 2, wherein said engine controller outputs a selected engine signal out of said engine signals, and said engine control signals to provide for said vehicle controller,

wherein said vehicle controller is configured to receive said selected engine signal as said interfacing signal, and to generate at least one of said plurality of said forklift component control signals in response to said selected engine signal.

7. The distributed control system according to claim 6, wherein said vehicle controller uses stored data therein in place of said selected engine signal when not receiving said selected engine signal during a predetermined period, and generates a second alarm signal, and

wherein said display unit displays a second alarm informing that said vehicle controller does not receive said selected engine signal in response to said second alarm signal.

8. The distributed control system according to claim 6, wherein said selected engine signal includes a rotation speed signal indicative of a rotation speed of said engine,

wherein said plurality of forklift component signals includes a sitting detection signal indicative of whether an operator is seated on a driver seat of said forklift,

wherein said plurality of forklift component control signals includes a transmission control signal for controlling a transmission of said forklift, and

wherein said vehicle controller generates said transmission control signal in response to said rotation speed signal and said sitting detection signal.

9. The distributed control system according to claim 2, wherein said plurality of controllers includes a finger chip controller controlling a finger chip control module, and

wherein said finger chip control module is disposed beside a driver seat to control forks and mast in response to actuation of finger-operable lever on said finger chip control module.

10. The distributed control system according to claim 2, wherein engine controller is disposed beside said engine, and

wherein said vehicle controller is positioned immediately inside a pivotable hatch provided for a body of said forklift.

11. A forklift comprising:

a forklift body; and

a distributed control system including;

a plurality of controllers mounted on said forklift body, each controlling a function of said forklift;

a network providing connections between or among said plurality of controllers within said forklift,

wherein a first controller out of said plurality of controllers is configured to control said function associated therewith in response to an interfacing signal received from a second controller out of said plurality of controllers, and

wherein said first controller controls said function associated therewith using data stored in said first controller in place of said interfacing signal when not receiving said interfacing signal during a predetermined period.

12. A method for operating a distributed control system within a forklift, comprising:

(a) transmitting an interfacing signal to a first controller out of a plurality of controllers from a second controller out of said plurality of controllers, wherein said plurality of controllers are connected through a network and configured to control functions of said forklift,

(b) first controlling a first function by said first controller in response to said interfacing signal,

(c) second controlling said first function by said first controller using stored data in said first controller in place of said interfacing signal when not receiving said interfacing signal during a predetermined period.

13. The method according to claim 12, further comprising:

(d) displaying an alarm on a display screen of a display unit connected to said network when said first controller does not receive said interfacing signal during said predetermined time,

wherein one of said first and second controllers is an engine controller, and another of said first and second controllers is a vehicle controller,

wherein said vehicle controller generates a plurality of forklift component controlling signals for controlling forklift components within said forklift, and

wherein said engine controller generates a plurality of engine control signals for controlling an engine of said forklift in response to a plurality of engine signals received from engine components of said engine.

14. The method according to claim 13, wherein said transmitting said interfacing signal includes:

(a1) outputting by said vehicle controller a selected forklift component signal selected out of said plurality of said forklift component signals and said plurality of said forklift component control signals to said engine controller,

wherein said first controlling said first function includes;

(b1) generating at least one of said engine control signals in response to said selected forklift component signal by said engine controller.

15. The method according to claim 14, wherein

said second controlling said first function includes:

(c1) said second controlling said first function using said stored data in place of said selected forklift component signal when not receiving said selected forklift component signal during said predetermined period,

wherein said displaying includes;

(d1) outputting a first alarm signal to said display unit by said vehicle controller, and

(d2) displaying a first alarm informing that said engine controller does not receive said selected forklift component signal in response to said first alarm signal.

16. The method according to claim 14, wherein said at least one selected forklift component signal includes a vehicle speed signal indicative of a speed of said forklift, and a vehicle speed limit signal indicative of a speed limit of said forklift,

wherein said plurality of said engine signals includes an accelerator sensor signal indicative of a state of an accelerator pedal of said forklift,

wherein said plurality of said engine control signals include a fuel injection rate signal indicative of an injection rate of said engines,

wherein said engine controller generates said fuel injection rate signal in response to said vehicle speed signal, said vehicle speed limit signal, and said fuel injection rate signal.

17. The method according to claim 13, wherein said transmitting said interfacing signal includes:

(a2) outputting by said engine controller a selected engine signal out of said engine signals, and said engine control signals to provide for said vehicle controller, and

wherein said first controlling includes;

(b2) generating at least one of said plurality of said forklift component control signals in response to said selected engine signal by said vehicle controller.

18. The method according to claim 17, wherein said second controlling includes:

(c2) controlling said first function by said vehicle controller using stored data therein in place of said selected engine signal when not receiving said selected engine signal during a predetermined period, and

wherein said displaying includes;

(d3) generating a second alarm signal when said vehicle controller does not receive said selected engine signal during said predetermined period,

(d4) displaying by said display unit a second alarm informing that said vehicle controller does not receive said selected engine signal in response to said second alarm signal.

19. The method according to claim 17, wherein said selected engine signal includes a rotation speed signal indicative of a rotation speed of said engine,

wherein said plurality of forklift component signals includes a sitting detection signal indicative of whether an operator is seated on a driver seat of said forklift,

wherein said plurality of forklift component control signals includes a transmission control signal for controlling a transmission of said forklift, and

wherein said vehicle controller generates said transmission control signal in response to said rotation speed signal and said sitting detection signal.

20. A computer program product recording a computer readable program for operating a distributed control system including a plurality of controllers connected through a network, said method comprising:

a code module for operating a second controller out of said plurality of controllers to transmit an interfacing signal to a first controller out of said plurality of controllers,

a code module for operating said first controller to control a first function in response to said interfacing signal,

a code module for operating said first controller to control said first function using stored data in said first controller in place of said interfacing signal when not receiving said interfacing signal during a predetermined period.

21. The computer program produce according to claim 20, wherein said computer program further comprising:

a code module for displaying an alarm on a display screen of a display unit connected to said network when said first controller does not receive said interfacing signal during said predetermined period.