HK1174982B - Communication technique by which an autonomous guidance system controls an industrial vehicle - Google Patents

Description

Communication method for controlling industrial vehicle by automatic guidance system

Cross reference to related applications

This application claims priority to U.S. provisional patent application 61/454,013 filed 3/18/2011.

Statement regarding federally sponsored research or development

None.

Technical Field

The present invention relates to industrial vehicles, such as pallet trucks; and more particularly to converting a manually operated vehicle for automatic guidance operation.

Background

Various types of industrial vehicles, including material handling vehicles, are used to handle items in factories, warehouses, freight transfer stations, stores, or other types of facilities. Conventional industrial vehicles are controlled by an operator on the vehicle. For example, to operate a warehouse efficiently and effectively, it is important to ensure that the equipment and operators are as efficient as possible. In order for warehouses to compete on a global scale, continuous improvements in production efficiency of industrial vehicle utilization are critical to cut costs. To achieve these goals, warehouse management systems are often employed to control inventory, ensure proper maintenance of equipment, and monitor operator and equipment efficiency. In these warehouse management systems, a centralized computer system monitors inventory flow, use of industrial vehicles, vehicle maintenance status, and operator performance.

To perform these functions, data needs to be collected for each industrial vehicle. To collect this data, sensors on the industrial vehicle feed back the data to a dedicated on-board computer that stores the data. Sometimes selected data is transmitted from the on-board computer to a central computer system within the facility in which the industrial vehicle is operating. The central computer system analyzes the data to determine the operation of each vehicle, the operation of the various operators within the facility. Data analysis also indicates when the vehicle requires maintenance and repair.

Industrial vehicles have become more sophisticated and a new type of automated guided vehicle has been developed. Automated guided vehicles (AVGs) are a form of mobile automated machinery that can transport goods and materials from one location to another in a confined environment, such as a factory or warehouse. Some AVGs follow a line buried under the floor and are therefore constrained to travel along a fixed path defined by the line. Guidance technology has advanced further so that the vehicle is no longer confined to a fixed path. Reference marks as reference bases are periodically set along various paths that the AVG may travel. In one embodiment, each fiducial has a unique appearance or optically readable code, such as a unique bar code. The AVG is assigned a path defined by a sequence of reference points disposed along the path. Optical sensors on the AVG sense adjacent reference points and the unique appearance or code of each reference point in the vehicle's operation, enabling the vehicle to determine its current location within the facility and determine the direction of travel along the set path.

Disclosure of Invention

Industrial vehicles can operate in an unmanned, automatic control mode or a manned, manual control mode. The present system provides an interface to the conventional control system of an industrial vehicle through which different types of guidance and navigation systems can be connected to the autonomous vehicle. The interface employs a predetermined protocol to exchange operating commands and data bi-directionally between the guidance and navigation system and the vehicle control system.

The industrial vehicle includes a guidance and navigation system that generates commands to guide the industrial vehicle along a path in an unmanned, autonomous operating state. The vehicle controller operates a propulsion drive system that drives the industrial vehicle.

The automated processing module is connected to the vehicle controller and to the guidance and navigation system via a communication network. An automated processing module receives first information from the guidance and navigation system specifying a speed of the propulsion drive system. The automated processing module responds to the received first information by instructing the vehicle controller how to operate the propulsion drive system.

In one embodiment, the first information includes a first value specifying a speed of the propulsion drive system and a second value specifying an amount by which the propulsion drive system turns wheels of the industrial vehicle. The first information may also specify a maximum speed at which the industrial vehicle is allowed to travel in the unmanned, automatic control mode. If the industrial vehicle has a device for lifting or lowering the transported goods, the first information further comprises an indicator indicating that the goods are lifted and another indicator indicating that the goods are lowered.

Another aspect of the invention relates to the automated processing module transmitting feedback information to the guidance and navigation system, the feedback information being indicative of actual operating parameters of the vehicle.

Drawings

FIG. 1 is a perspective view of an industrial vehicle of the present invention;

FIG. 2 is a block diagram of a control system of an industrial vehicle, wherein the control system includes a guidance and navigation system that is coupled to a vehicle controller via a communication link;

3-5 depict data formats of three process data objects used to transmit information from a guidance and navigation system to a vehicle controller; and

FIGS. 6 and 7 depict data formats of two process data objects used to transfer information from a vehicle controller to a guidance and navigation system.

Detailed Description

The present invention relates to the operation of an industrial vehicle. Although the invention has been described in the context of a pallet truck for a warehouse, the concepts of the invention are applicable to other types of industrial vehicles and they may be used in a variety of different facilities, such as factories, freight transfer stations, warehouses, stores.

Referring initially to fig. 1, an industrial vehicle 10, and in particular a pallet truck, includes an operator compartment 11, the operator compartment 11 having an opening for operator access. Connected to the operator compartment 11 is an operating lever 14, which operating lever 14 is one of several operating control means 17. The industrial vehicle 10 includes a load carrier 18, such as a pair of forks, which is raised and lowered relative to the frame. As will be described in further detail below, the communication system on the industrial vehicle is capable of exchanging data and commands with an external warehousing system via the antenna 15 and wireless signals.

The industrial vehicle 10 also includes a guidance and navigation system (GANS) 13. Any of several types of guidance and navigation systems may be used to determine the path of an industrial vehicle, sense the position of the vehicle, and operate traction devices, steering devices, and other devices to guide the vehicle along a prescribed path. For example, the GANS13 may determine its location and travel path by sensing buried wires, magnetic tape on the building floor, or magnetic markers placed adjacent to the path. Alternatively, the GANS13 may use laser scanners to sense fiducials placed throughout the warehouse to determine the desired path. Yet another commercially available GANS13 has one or more video or still cameras whose output signals are processed by image recognition software. Navigation techniques using dead reckoning may also be utilized. For systems that use camera or dead reckoning navigation techniques, each path of the industrial vehicle is taught by manually driving the vehicle as the GANS13 "learns" the path.

Thus, the industrial vehicle 10 is a hybrid control vehicle that may be controlled by an operator in the operator compartment 11 on the vehicle or may be unmanned with the automatic control mode provided by the GANS 13.

Fig. 2 is a block diagram of the control system 20 of the industrial vehicle 10. The control system 20 includes a vehicle controller 21, which is a microcomputer device including a memory 24, an analog-to-digital converter, and an input/output circuit. The vehicle controller 21 executes a software program that responds to commands from the operator controller 17 or the GANS13 and manipulates the vehicle components that drive the industrial vehicle and transport the transported cargo. The controller's input/output circuitry receives operator input signals from the operator controls 17 to initiate and manage the operation of vehicle activities such as forward and reverse travel, steering, braking, and raising and lowering the load carrier 18. In response to the operator input control signals, vehicle controller 21 sends command information to lift motor controller 23 and propulsion drive system 25 via first communication network 26, with propulsion drive system 25 including traction motor controller 27 and steering motor controller 29. The propulsion drive system 25 provides motive force for propulsion of the industrial vehicle 10 in a selected direction, and the lift motor controller 23 drives the cargo vehicle 18 to raise and lower a load 35, such as warehoused cargo. The first communication network 26 may be any of several well-known networks for exchanging commands and data between machine components, such as a Controller Area Network (CAN) serial bus that uses the communication protocol of ISO-11898 promulgated by the international organization for standardization in geneva, switzerland.

The industrial vehicle 10 is powered by a battery pack 37, and the battery pack 37 is electrically connected to the vehicle controller 21, the propulsion drive system 25, the steering motor controller 29, and the lift motor controller 23 through a fuse or set of fuses in a power splitter 39.

The traction motor controller 27 drives at least one traction motor 43, the traction motor 43 being connected to drive wheels 45 to provide motive force for the industrial vehicle. The rotational speed and direction of rotation of the traction motor 43 and associated drive wheels 45 is dictated by the operator via the joystick 14 and is monitored and controlled by feedback from the rotation sensor 44. The rotation sensor 44 may be an encoder coupled to the traction motor 43 and its signal is used to measure the speed and forward and reverse distances traveled by the vehicle. The drive wheels 45 are also connected to the friction braking device 22 through the traction motor 43 to provide both a service and parking brake function for the industrial vehicle 10.

The steering motor controller 29 is operatively connected to a drive steering motor 47, and the drive steering motor 47 can change the direction of the steering wheel 48 in a direction selected by the operator turning the joystick 14 as described above. The direction and amount of rotation of the steerable wheels 48 determines the angle at which the industrial vehicle 10 travels. Another encoder is coupled to the steerable wheel 48 or steering linkage as a steering angle sensor 49 to sense the angle of rotation of the steerable wheel. In addition, the drive wheels 45 may steer the vehicle, in which case the steering angle sensor 49 senses the steering motion of the drive wheels.

The lift motor controller 23 sends command signals to control the lift motor 51, the lift motor 51 being connected to a hydraulic circuit 53, the hydraulic circuit 53 forming a lift assembly for lifting and lowering the load carrier 18. As described below, the height sensor 59 provides a signal to the vehicle controller 21 indicative of the height of the cargo vehicle relative to the frame of the industrial vehicle 10. Likewise, a weight sensor 57 is mounted on the cargo vehicle 18. A cargo sensor 58 is mounted adjacent the cargo vehicle 18 to determine whether cargo is being transported. For example, the cargo sensor 58 may be a Radio Frequency Identification (RFID) tag reader, a Rubee device conforming to the IEEE1920.1 standard, a bar code reader, or other device capable of reading the corresponding identification on the cargo or on the pallet on which the cargo is stored. The weight sensor 57 may be used alone to provide a signal that the vehicle controller 21 uses to provide the quantity of cargo that the industrial vehicle has transported and the total tonnage of the cargo that has been carried. Because of this function, the vehicle controller 21 increments the cargo count each time the signal from the weight sensor 57 indicates that cargo is being put on and then removed from the cargo vehicle 18.

Still referring to fig. 2, a plurality of data input and output devices are connected to the vehicle controller 21, including, for example, vehicle sensors 60 for monitoring parameters such as temperature and battery charge, user data input devices 61, communication ports 65, and service ports 64. The user data input device 61 allows a vehicle operator, supervisor, or other person to input data and configuration commands into the vehicle controller 21, and may be implemented by a keyboard, a series of discrete buttons, a mouse, a joystick, or other input devices apparent to those skilled in the art. The service port 64 enables a technician to connect a portable computer (not shown) to the industrial vehicle 10 for purposes of diagnostics and configuration program commands.

The vehicle controller 21 stores sensed data regarding the operation of the vehicle in the memory 24. In addition, the stored data may include information generated by the vehicle controller 21, such as the number of hours of operation, the state of charge of the battery, and an operational fault code. The cargo lift operation monitoring includes the total time that the lift motor 51 is running, data from the weight sensor 57 and data from the height sensor 59. These sensor data can also be used to measure the total time the vehicle is unloaded, also referred to as dead time. Accurate information about the load 35 being transported can be obtained by the cargo sensor 58. Various movement parameters, such as vehicle operation and speed and acceleration of the cargo vehicle 18, are also monitored in the exemplary industrial vehicle 10.

The vehicle controller 21 provides some data to an operator display 66, and the operator display 66 displays information to the vehicle operator. The operator display 66 displays vehicle operating parameters such as travel speed, battery level, operating time, current time, and maintenance required. Temperature sensors monitor the temperature of the motor and other components and these data are displayed. An alarm is provided on the operator display 66 to notify the vehicle operator of a vehicle condition that requires attention.

The guidance and navigation system (GANS)13 generates control signals that are used to operate the hoist motor controller 23, the traction motor controller 27, and the steering motor controller 29 to guide vehicle operation in the autonomous mode of operation. In particular, the GANS13 is connected to a second communication network 70, such as another CAN serial bus, through a lead connector 71, which is connected to an Automated Processing Module (APM) 74. The APM74 is connected to the first communication network 26 and, therefore, allows program commands and data information to be exchanged with the vehicle controller 21. The APM74 may have another serial port 75 to connect to a programming device. The APM74 is a microcomputer device that executes software to control the exchange of information between the GANS13 and the vehicle controller 21. The APM74 isolates the first communication network 26 from the second communication network 70, which prevents abnormal signals on the lead connector 71 from adversely affecting information communicated over the first communication network. To accomplish this function, the APM74 examines each piece of information received over the second communications connection network 70 to ensure that the information content is consistent with the operation of the industrial vehicle. Only consistent content is transferred to the first communication network 26 through the APM.

The communication port 65 is connected to a wireless communication device 67. the wireless communication device 67 includes a transceiver 69 connected to an antenna 15 that can exchange data and commands with a vehicle management computer in a warehouse or plant in which the industrial vehicle 10 operates via a wireless communication network. Any of several well-known serial communication protocols, such as Wi-Fi, may be used to exchange information and data over the bi-directional communication lines. Each industrial vehicle 10 has a unique identifier, such as a production serial number or a communication network address, that ensures that information is specifically communicated to the designated vehicle.

Wireless communication is used by industrial vehicles to transmit data on their operating conditions to a central computer in a warehouse. The central computer analyzes the received data to determine how each vehicle is operating relative to other vehicles in the warehouse and relative to a reference of a particular type of industrial vehicle. The collection, transmission, analysis of data regarding the operation and operating conditions of Industrial Vehicles and operators has been described in published U.S. patent application No2009/0265059 entitled "System for managing operation of Industrial Vehicles" the disclosure of which is hereby incorporated by reference. The wireless communication system may also communicate instructions to the industrial vehicle. For example, when operating in an automatic control mode, a warehouse dispatcher can send cargo transportation tasks to an industrial vehicle. The information may specify a particular route for the industrial vehicle to travel.

The industrial vehicle 10 is hybrid controlled and may be controlled by an operator on the vehicle at certain times and automatically at other times. For example, an operator manually drives a manual-automatic hybrid control industrial vehicle through a warehouse to a storage location for a desired cargo, and the cargo is loaded onto the cargo vehicle 18 of the vehicle. The industrial vehicle is then manually driven to a first staging area. At a first staging area, the operator places the industrial vehicle 10 in an autonomous mode of operation using the user control panel 72 of the GANS13 and specifies a path to travel to a second staging area, such as a nearby dock. These paths are typically pre-set to standard operation by storing data in GANS 13.

For example, some common navigation technology devices require the GANS13 to learn each path that may be subsequently taken by the industrial vehicle 10. This learning occurs in a training mode in which the vehicle is manually driven along a particular route, while the GANS13 stores data relating to that route. The classification of the data depends on the type of navigation technology equipment employed, and may include identification of particular reference points encountered, the distance between stop and turn, the direction and angle of turn, the speed in different path segments, and the like. The detailed information of the path is collected by the sensors and vehicle controller and transmitted to the GANS for storage. A detailed path can be taught to one industrial vehicle 10 and the data obtained can be transmitted to another vehicle of the same model, thus eliminating the need for each vehicle to manually navigate the path in the training mode.

Returning to the embodiment depicted in FIG. 2, where the vehicle is located in the first staging area, the auto mode command and path assignment are entered into the user control panel 72 of the GANS 13. The input devices are connected to the vehicle controller 21, and the vehicle controller 21 transmits the communication to the guidance and navigation system 13 through the first communication network 26, the APM74, the second communication network 70. The operator then steps off the industrial vehicle, which action can be detected by the pressure sensing floor mat 12 in the operator compartment 11 (see fig. 1). This causes the control system 20 to enter the automatic control mode of operation. Thereafter, if a person stands on the pressure sensing floor mat 12, the control system 20 will automatically switch to the manual mode of operation.

In the automatic control mode, the GANS13 controls operation of the industrial vehicle 10. This control includes the GANS13 transmitting operating commands to the vehicle controller 21 to directly operate the lift motor controller 23, the traction motor controller 27 and the steering motor controller 29 in the same manner as the manual control mode when the on-board operator manipulates the operating controls 17. For example, the GANS13 generates a speed command specifying a direction and speed for the traction motor 43 to drive the drive wheels 45. This operation command is carried by a message that is communicated to the APM74 through the second communication network 70. Upon receipt of the message, the APM formats the message into an address for transmission to the vehicle controller 21, and then transmits the format-converted message via the first communication network 26.

Upon receiving the formatted information, the vehicle controller 21 extracts the operating commands and uses this information to control the operation of the industrial vehicle 10, as in the manual mode, the vehicle controller receives commands similarly generated in response to the operating controller 17. In any event, the vehicle controller 21 will first check the operation command to ensure that the specified operation is appropriate for controlling the industrial vehicle 10 at that time. This check will filter out the operating commands and control data issued by the GANS13 to prohibit conflicting, improper vehicle operations from occurring. For example, the vehicle controller 21 can disable such a command from the GANS 13: when the load carrier 18 is lifted with heavy loads, the traction motor drive 27 is operated to advance at full speed. If the information of the APM74 includes the correct operating commands, the vehicle controller 21 will format the control commands for the equestrian controller 23, 27 or 29 associated with the corresponding vehicle function. For example, the vehicle controller 21 responds to the speed command from the APM by sending a control command to the traction motor controller 27 and communicating the control command over the first communication network 26 in an informational manner. The traction motor controller 27 responds to the received control commands by driving the traction motor 43 directly.

In a similar manner, the GANS13 sends operating commands to the vehicle controller 21 requesting the steering controller 29 to turn the steerable wheels 48 in a specified direction, a specified angle, so that the vehicle 10 travels along a specified path. Likewise, in the automatic control mode, operating commands are issued by the GANS13 to control the hoist motor controller 23 and other components on the industrial vehicle 10.

When the industrial vehicle 10 is operating in the automatic control mode, the sensors on the GANS13 detect the position of the vehicle relative to the designated path. In one type of GANS, a camera or laser scanner detects fiducials that are periodically placed along different paths in the warehouse. The datum points may be provided on the warehouse floor, wall, column or shelf. Each reference point has a unique external feature or optically readable code, e.g., a unique bar code, thereby enabling the GANS13 to determine the current position of the vehicle and the direction to the next reference point along a specified path. This information allows the GANS13 to determine when and how to turn the steerable wheels 48 to cause the industrial vehicle to follow a specified path. Other navigation technology devices may also be used with the GANS13, such as buried wires, magnetic tape on the floor, magnetic markers placed along the path, or the use of image processing software to identify features along a specified path in the warehouse.

If the GANS13 is capable of maneuvering the load vehicle 18, lift and lower operation commands are sent instructing the vehicle controller 21 to generate appropriate control commands instructing the lift motor controller 23 to drive the lift motor 51. Those control commands generated in response to the GANS are equivalent to those received by the hoist motor controller in response to the on-board operator manipulating the operator controls 17 in the manual control mode. When the load vehicle 18 is being raised or lowered, the load vehicle height sensor 59 sends a feedback signal that assists the vehicle controller 21 in operating the lift motor controller 23.

The automation module 74 and the second communication network 70 enable different types of guidance and navigation systems 13 to be used with the industrial vehicle 10 and its control system 20. These guidance and navigation systems 13 can employ any of a variety of conventional navigation technology devices that provide commands that request the APM74 in the proper format to command the vehicle controller 21 how to operate the motors and other components of the control system 20.

The first communication network 26 and the second communication network 70 utilize a serial bus protocol to transmit information carrying operational commands. Each piece of information, commonly referred to as a Process Data Object (PDO), includes eight bytes of data, which are used as operation commands, for example. A set of process data objects, referred to as Transmit Process data objects (TPDO's), are used to transmit information from the GANS13 to the APM 74. Another set of process data objects, referred to as received process data objects (RPDO's), are used to define information sent from the APM74 to the GANS 13. "send" and "receive" indicate the direction of information relative to the GANS. Similar process data object forming information is transmitted between the APM74 and the vehicle controller 21 and between the vehicle controller 21 and the motor controllers 23, 27, and 29 over the first communication network 26.

3-7 depict the information data format of process data objects conveyed between the GANS13 and the APM 74. Referring to FIG. 3, for example, a first transmitted process data object (TPDO1) is transmitted from the GANS13 to the APM74 every 20 milliseconds. Bytes 0 and 1 of TPDO1 provide a signed number that specifies the requested speed of the vehicle, i.e., the setting of the traction throttle, as an operating command. The sign of the value determines the direction, forward or reverse, in which direction the value determines the speed required. This value is similar to the throttle setting generated by the vehicle controller 21 in the manual operating mode. The next double byte defines the maximum speed at which the vehicle is allowed to operate in the automatic control mode and the training mode. Thus, if the throttle setting indicated by the first double byte exceeds this limit, the APM74 limits the speed to a level determined by bytes 2 and 3. When the TPDO1 bytes are transmitted to the vehicle controller 21, the first four bytes are used by the latter devices to form a speed and direction command, which is then sent over the first communication network 26 to the traction motor controller 27. The traction motor controller 27 responds to the speed command by operating the traction motor 43 and brake 22 accordingly.

Bytes 4 and 5 of TPDO1 provide a signed number that defines the amount the steering motor controller 29 turns the steering wheel 48. The sign of the value determines the direction of rotation, left or right, and the value determines the amount of wheel rotation. This value is the same as the steering command generated by the vehicle controller 21 in the manual operating mode. Upon receiving the TPDO1 bytes transmitted by the APM74, the vehicle controller 21 forms a steering command using bytes 4 and 5, which is sent over the first communication network 26 to the steering motor controller 29. The steering motor controller 29 responds to the steering command by operating the steering motor 47 accordingly.

The bits of byte 6 in TPDO1 are used as a flag that indicates the operation of particular functions and components of industrial vehicle 10. Bit 0 is a lift command which when true indicates that the lift motor 51 should be activated to lift the cargo vehicle 18. True at bit 1 indicates that the hoist motor 51 should be activated to lower the load carrier 18. The raised and lowered positions indicate that the load carrier is operating at a single predetermined speed. The logic level of bits 0, 1 causes vehicle controller 21 to generate a command that is then sent over first communication network 26 to hoist motor controller 23, and hoist motor controller 23 responds to the command by operating hoist motor 51 accordingly. Bit 2 of byte 6 is used to activate horn 28 on industrial vehicle 10 to alert or summon supervisory personnel in the vicinity of the vehicle. Bits 6, 7 of byte 6 represent one of the following control modes of the industrial vehicle 10: a manual control mode, an automatic control mode, and a training mode. Bits 2-5 are reserved for use.

In the automatic control mode, bits 4-7 of byte 7 of TPDO1 transfer a value that changes with each TPDO1 message, thereby informing APM74 GANS13 of a state where the card is operational and no data is being repeatedly transferred for the same card. If, in the automatic control state, the APM74 does not receive the TPDO1 within a predetermined time (e.g., 100ms) after receiving the previous TPDO1, or receives two consecutive TPDOs 1 with the same 4-7 bit value of byte 7, then the APM will send a signal to the vehicle controller 21 to stop the industrial vehicle and terminate all other operations controlled by the GANS 13.

Referring to FIG. 4, for example, approximately once per second, the GANS13 also transmits another information referred to as the second process data object TPDO 2. TPDO2 includes information used to configure the operation of traction motor controller 27 when the vehicle is in a training or automatic control mode. The first two bytes of TPDO2 provide a steering limit that prevents the operator from steering the wheels through excessive angles in the training mode. The vehicle controller 21 uses this value to limit the angle by which the steerable wheels 48 are turned to the right or left in the operating mode.

Byte 2 of TPDO2 specifies the full speed acceleration in automatic control mode. This acceleration is used when the traction motor 43 is requested by the GANS13 to change from a relatively low speed defined by low throttle to full speed. Byte 3 provides a similar low-speed acceleration for transitioning from a low throttle setting to a high throttle setting, the high throttle setting being less than 100% full speed. Byte 4 of TPDO2 is an intermediate deceleration in automatic control mode, which defines the deceleration at which the vehicle is permitted to decelerate when the throttle demand from GANS (bytes 0 and 1 of TPDO1) is set to 0. Byte 5 defines the braking speed that occurs when the GANS throttle request specifies a reverse direction or when the GANS requests to activate the brakes 22 in the automatic control mode. Byte 6 defines the partial deceleration in the automatic control mode that is employed to reduce speed when transitioning from the high throttle setting to the low throttle setting. The APM74 transmits the PDO received from the GANS13 to the vehicle controller 21, which the vehicle controller 21 utilizes in converting the speed change request from the GNS to a speed command for the traction motor controller. That is, the vehicle controller 21 gradually increases the motor speed command so neither the acceleration nor the deceleration exceeds the limit. These defined speeds prevent the industrial vehicle 10 from accelerating or decelerating excessively.

In byte 7 of TPDO2, only the 7 th bit is used as a stuff bit that triggers each successive transfer of TPDO 2. This enables the APM74 to check whether the GANS13 transmission is a duplicate transmission of the same information.

In addition to the speed, acceleration and steering limits provided in the transmission process data object, it should also be noted that similar limits are also stored in the vehicle controller 21, including some more stringent limits in sequence.

Another message, designated as the third transfer process data object TPDO3, is sent by the GANS13 approximately once per second and provides the APM74 and the vehicle controller 21 with error information checked by the GANS. Bytes 0 and 1 of TPDO3, as shown in fig. 5, indicate the occurrence of various errors in the operation of the GANS 13. In this embodiment only the 0 th bit in byte 2 is used, which is used as a display flag when an obstacle is detected in the path of the industrial vehicle 10. This bit causes the APM74 to send a message to the vehicle controller 21 that an obstacle has been detected, and the vehicle controller 21 communicates this information to the vehicle management computer in the warehouse via the wireless communication network. This alerts the warehouse supervisory personnel to clear the obstacle in the operation of the industrial vehicle so that corrective action can be taken.

In the current embodiment, bytes 3-6 of TPDO3 are not used. Only the 7 th bit of byte 7 is used as a stuff bit and triggers each successive transfer of TPDO 3. This enables the APM74 to check whether the GANS13 repeatedly transmitted the same information.

The automated processing module 74 can send information over the second communication network 70 to the GANS 13. This information feeds back data regarding the operating parameters and conditions of the industrial vehicle 10 to the GANS 13. Some of this data informs the GANS about the vehicle's response to the operation request sent by the GANS. Such information includes received process data objects ((RPDO's) designated as received by the GANS 13.

A first received process data object (RPDO1) is transmitted by the APM74 approximately once every 20 milliseconds. As depicted in fig. 6, bytes 0 and 1 include a signed numerical value that indicates the actual steering position of the steering wheel 48 set by the steering motor 47. The sign of the numerical value indicates whether to turn left or right, and the magnitude of the numerical value indicates the amount or angle of turning. Bytes 2 and 3 of RPDO1 form a signed value indicating the actual speed of the traction motor and whether the sign indicates forward or backward travel. Bytes 4 and 5 provide corresponding amperage values for the traction motor current.

Byte 6 of RPDO1 shows the state of the rechargeable battery in a 0-100% manner. The vehicle controller 21 receives power data from the power distributor 39 and uses the data to determine the state of charge of the battery using any of a number of well-known techniques. This information is then transmitted to the APM 74. The various bits of byte 7 show various operating parameters. 0. The 1 bit provides a digital signature of the vehicle in the control mode in which the controller 21 is actually operating. These modes include manual control mode, automatic control mode, training mode. The GANS13 automatically sets its operating mode in response to receiving this alignment. Bit 2 of byte 7 specifies the state of the brake switch. Bit 3 specifies whether the industrial vehicle can be placed in automatic control mode. If the bit is set to 0, the industrial vehicle 10 is prevented from entering the automatic control mode when commanded by the GANS 13. The remaining bits of byte 7 are unused.

Referring to FIG. 7, the APM74 also transmits a second received process data object (RPDO2) to the GANS13 approximately once per second. The process data object provides vehicle identification and detailed data. The first three bytes contain the serial number of the particular industrial vehicle 10. Byte 3 shows the version of the primary software newly installed by the vehicle controller 21, and byte 4 shows the version of the secondary software newly installed by the vehicle controller 21. Byte 5 shows the inches of the industrial vehicle wheelbase. Byte 6 shows the number of inches of the maximum lift height of the vehicle and byte 7 of RPDO2 shows the maximum lift load of the vehicle.

The foregoing description has generally described one or more embodiments of the invention. While various changes have been noted and are made within the scope of the invention, it is contemplated that those skilled in the art will derive from the disclosure of the embodiments of the invention many other changes. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.

Claims (30)

1. A guidance and navigation system for operating an industrial vehicle in an unmanned/autonomous control mode, wherein the industrial vehicle comprises a vehicle controller and a propulsion drive system, the vehicle controller being connected to a first communication network, the propulsion drive system being for driving the industrial vehicle, the industrial vehicle further comprising an autonomous processing module connected to send information over the first communication network and to a second communication network; and

the guidance and navigation system is operative to determine a path to be taken and to guide the industrial vehicle along the path by sending first information to the automated processing module via the second communication network, wherein the first information includes a first value specifying a speed of the propulsion drive system and a second value specifying an amount by which the propulsion drive system turns wheels of the industrial vehicle, the first information causing the automated processing module to send first and second values of reformatted information to the vehicle controller via the first communication network instructing the vehicle controller to use the first and second values to send at least one operating command to the propulsion drive system.

2. The guidance and navigation system of claim 1, wherein the first information further specifies a maximum speed at which the industrial vehicle is allowed to travel in the unmanned/autonomous control mode.

3. The guidance and navigation system of claim 1, wherein the industrial vehicle has a device to lift and drop a cargo being carried, and the first information further includes one indicator indicating that the cargo is lifted and another indicator indicating that the cargo is dropped.

4. The guidance and navigation system of claim 1, wherein the first information issued by the guidance and navigation system includes an indicator indicating whether the industrial vehicle is operating in the unmanned/automatic control mode or manned/manual control mode.

5. The guidance and navigation system of claim 1, wherein the first information includes a value that changes each time the automated processing module transmits the first information over the second communication network.

6. The guidance and navigation system of claim 1, wherein the guidance and navigation system sends second information over the second communication network, the second information indicating wheel steering angles, vehicle propulsion acceleration, vehicle propulsion deceleration, and braking speed limits.

7. The guidance and navigation system of claim 1, wherein the guidance and navigation system transmits third information over the second communication network, the third information indicating whether the industrial vehicle encountered an obstacle in its path.

8. The guidance and navigation system of claim 1, wherein the guidance and navigation system receives a feedback information over the second communication network, wherein the feedback information is indicative of an actual speed of the industrial vehicle.

9. The guidance and navigation system of claim 1, wherein the guidance and navigation system receives feedback information over the second communication network, wherein the feedback information indicates an actual speed of the industrial vehicle, a wheel steering amount of the industrial vehicle, a battery state of charge, and a braking state.

10. The guidance and navigation system of claim 1, wherein the guidance and navigation system receives feedback information over the second communication network, wherein the feedback information indicates whether to operate in the unmanned/automatic control mode, the manned/manual control mode, or the training mode.

11. A method of controlling an industrial vehicle in an unmanned/autonomous control mode, wherein the industrial vehicle includes a propulsion drive system that is manipulated by a vehicle controller to propel the industrial vehicle along a path and an autonomous processing module operatively connected to send commands to the vehicle controller in response to information received via a communication network, the method comprising:

a guidance and navigation system that determines a path to be taken by the industrial vehicle;

responsive to the path, the guidance and navigation system transmitting a first message to the automated processing module over a communication network, wherein the first message includes a first value specifying a speed of the propulsion drive system and a second value specifying an amount by which the propulsion drive system turns the wheels of the industrial vehicle,

the automated processing module sending the first and second values in the reformatted information to the vehicle controller; and

the vehicle controller responds to the reformatted information by controlling operation of the propulsion drive system.

12. The method of claim 11, wherein the first information further specifies a maximum speed at which the industrial vehicle is allowed to travel in the unmanned/autonomous control mode.

13. The method of claim 11, wherein the industrial vehicle has a device to lift and drop a carried cargo, and the first information further comprises an indicator indicating that the cargo is lifted and another indicator indicating that the cargo is dropped.

14. The method of claim 11, wherein the first information includes an indicator that indicates whether the industrial vehicle is operating in the unmanned/automatic control mode or the manned/manual control mode.

15. The method of claim 11, wherein the first information includes a value that is changed by the guidance and navigation system each time the first information is transmitted over a communication network.

16. The method of claim 11, further comprising the guidance and navigation system transmitting second information over the communication network, wherein the second information indicates wheel steering angles, vehicle propulsion acceleration, vehicle propulsion deceleration, and braking speed limits.

17. The method of claim 11, further comprising the guidance and navigation system transmitting third information over the communication network, wherein the third information indicates whether the industrial vehicle encountered an obstacle in its path when the operating in the unmanned/autonomous control mode.

18. The method of claim 11, wherein the guidance and navigation system receives feedback information from the automated processing module, wherein the feedback information is indicative of an actual speed of the industrial vehicle.

19. The method of claim 11, wherein the guidance and navigation system receives feedback information from the automated processing module, wherein the feedback information indicates an actual speed of the industrial vehicle, a wheel steering amount of the industrial vehicle, a battery state of charge, and a braking state.

20. The method of claim 11, wherein the guidance and navigation system receives feedback information from the automated processing module indicating whether to operate in the unmanned/automatic control mode, manned/manual control mode, or training mode.

21. An industrial vehicle comprising:

a propulsion drive system for propelling the industrial vehicle;

a vehicle controller for operating the propulsion drive system;

a first communication network over which the vehicle controller and the propulsion drive system exchange information;

a second communication network;

an automatic processing module for connecting the first communication network and the second communication network; and

a guidance and navigation system including sensors for detecting the position of the industrial vehicle and, in an unmanned/autonomous mode of operation, determining a path to be taken and generating commands to guide the industrial vehicle along the path and operative to send first information to the automated processing module via the second communication network, wherein the first information includes a first value specifying a speed of the propulsion drive system and a second value specifying an amount by which the propulsion drive system turns the wheels of the industrial vehicle, the automated processing module transmitting the first and second values to the vehicle controller via the first communication network, the automated processing module checking the first and second values and transmitting the first and second values only if the first and second values are compatible with operation of the industrial vehicle Two values.

22. The industrial vehicle of claim 21, wherein the first information further specifies a maximum speed at which the industrial vehicle is allowed to travel in the unmanned/automatic control mode.

23. The industrial vehicle of claim 21, wherein the industrial vehicle has a device for lifting and lowering a load being carried, and the first information further comprises one indicator indicating that the load is lifted and another indicator indicating that the load is lowered.

24. The industrial vehicle of claim 21, wherein the first information comprises an indicator indicating whether the industrial vehicle is operating in the unmanned/automatic control mode or the manned/manual control mode.

25. The industrial vehicle of claim 21, wherein the first message includes a value that changes each time the first message is transmitted over the second communication network.

26. The industrial vehicle of claim 21 wherein the guidance and navigation system sends second information to the automated processing module, the second information specifying limits for wheel steering angle, vehicle propulsion acceleration, vehicle propulsion deceleration, and braking speed.

27. The industrial vehicle of claim 21 wherein the guidance and navigation system sends third information to the automated processing module, the third information specifying whether the industrial vehicle encountered an obstacle in its path when operating in the unmanned, autonomous control mode.

28. The industrial vehicle of claim 21, wherein the automated processing module sends feedback information to the guidance and navigation system, wherein the feedback information indicates an actual speed of the industrial vehicle.

29. The industrial vehicle of claim 21, wherein the automated processing module sends feedback information to the guidance and navigation system, wherein the feedback information indicates an actual speed of the industrial vehicle, a wheel steering amount of the industrial vehicle, a battery state of charge, and a braking state.

30. The industrial vehicle of claim 21 wherein the automated processing module sends feedback information to the guidance and navigation system indicating whether to operate in an unmanned, automatic control mode, a manned, manual control mode, or a training mode.