This invention relates to an apparatus and a method employed to pick up a. string of roadway barrier segments at one location and relocate the string at a second location. More par-ticularly, the invention employs a system for automatically guiding a machine that picks up and places the roadway barrie segments,

BACKGROUND OF THE INVEN ION

It is well known to use self-powered wheeled machines to pick up and move roadway barrier segments disposed .end-to-end from one location or another. Some of these roadway barrier moving machines move along a string of roadway barrier segments, lift the string and transfer the string to another location through the use of a conveyor. One example of such, a barrier transfer machine is manufactured by Lindsay Transportation Solutions, 180 River Road, Rio ista., California and ma.de available under the Barrier Systems and Quick Change trademarks . Barrier transfer machines are steered and operated either solely by manual control or anual control in conjunction with infra ruc ure modificat ons such as above or below grade guide wires or magnetic tape.

As wi l be discussed in greater detail below, the system of this invention automatically guides a machine tha picks up and places roadway barrier segments using global satellite positioning (GPS) and ultrasonic technologies. The ^' machine is guided by both GPS signals and signals based on ultrasonic measurements from the existing barrier segments.

It. is known, of course, to guide vehicles generally based on GPS sensing and also generally based o ultrasonic sensing of some type. Examples of such guidance systems are show in. the following prior art: U, S , Patent No. 5,549,412, issued August 27, 1996, U.S. Patent Application Pub. No. US 2010/0215433, published August 26, 2010, U.S. Patent No. 5,052,854, issued October 1, 1991, U.S. Patent Application Pub. No. US 2010/0202829, published August 12, 2010, U.S. Patent No. 6,220,780, issued April 24, 2001, U.S. Patent No. 6,022,168, issued February 8, 2000, U.S. Patent No. 5,253,951, issued October 19, 1993, French Patent No. R2782331A1, issued February 18, 2000 and European Patent No. EP1319757A2, issued June 18, 2003.

DISCLOSURE OF INVENTION

In the present invention the approaches of GPS sensing and ultrasonic sensing cooperate in a unique manner to perform specific tasks in association with structural features of roadway barriers and roadway barrier placement equipment .

The apparatus of the invention moves relative to a string of roadway barrier segments disposed end-to-end at a first location and during movement serially picks up roadway barrier segments of the string and transports the picked-up roadway barrier segments to relocate the string at a second location.

The apparatus includes a wheeled machine having an inlet receiving the string of roadway barrier segments at the first location.

An ultrasonic sensor is mounted on the wheeled machine for sensing the location of the string at the first location relative to the wheeled machine.

A first steering control is operatively associated with the ultrasonic sensor and with wheels of the machine to steer the wheels operatively associated therewith and maintain the inlet positioned to serially receive the roadway barrier segments at the first location.

A GPS receiver is mounted on the wheeled machine for sensing the location of the machine relative to a predetermined path of movement. A second steering control is operatively associated with the GPS receiver and with wheels of the wheeled machine to steer the wheels operatively associated therewith and maintain movement of the wheeled machine along the. predetermined path of movement when depositing the picked-u barrier segments to relocate the string at the second location.

The invention also encompasses a method of relocating a string of roadway harrier segments disposed end-to-end from a first locatio to a second location employing a moving wheeled machine having an inlet to serially pick up roadway barrier segments of the string and transport, the picfced-up roadway barrier segments to relocate the string at the second location. The method incorporates steps utilizing ultrasonic and GPS sensor systems ,

Other features _. , advantages and objects of the present invention will become apparent with reference to the following description and accompanying drawings ,

BRIEF DESCRIPTION OF DRAWINGS

Fig, I is a, perspective view illustrating a self- propelled wheeled machine picking up and transporting to another location a string of roadway barrier segments, elements of the GPS guidance, system employed in the invention being illustrated schematically;

Fig. 2 is a diagramma ic , plan view of the vehicle and string being transferred thereby;

Fig. 3 is an enlarged, plan, diagrammatic view illustrating steering of vehicle wheels under the control of signals received from GPS and ultrasonic systems; and

Fig. 4 is a schematic presentation of circuitry and operational features of the apparatus of the inven on employed with the wheeled vehicle,

BEST MODE FOR CARRYING OPT THE X1QYENTX0N

Referring now to the drawings, apparatus 10 constructed in accordance with the teachings of the present invention is illustrated. Th apparatu moves relative to a. string of roadway barrier segments 12 disposed end-to-end at a first location which, may,, for example,- foe an off road location. During movement of the: apparatus the roadway barrier segments of the string are p cked-up and transported to relocate the string at a second location,, which may, for example, ^' be a .location on a roadway.

Apparatus 10 includes a wheeled, self-propelled machine 14 having an inlet 16 receiving the string of roadway harrier segments at the first location. ig, 2 illustrates by means of arrows movement of the wheeled machine, the right end of the machine being the leading or pick-up end and the left end of the machine being the following or discharge end. As indicated above, machines of this type are known, the Quickchange ba-xriex transfer machine made available by the Barrier Systems unit of Lindsay Transportation Solutions being an example. In the machine the string of roadway barrier segments passes through an inlet opening formed by a " snou " at the leading end of the machine -whereupon the roadway barrier segments are picked-up and moved by a conveyor, such as conveyo 18 shown in Fig, 1, and delivered from an exit 20 at the discharge end of the machine offset from, the snout inlet.

Machine 14 has wheels 22 at the leading end thereof and wheels 24 at the discharge end thereof , The pairs of front wheels 22 and rear wheels 24 are independently steerable, the wheel pairs being supported by independent wheel support systems 26, 28 (see Fig. 3} of any suitable type. Steering may be accomplished through utilization of hydraulic proportional valves 30, The hydraulic proportional valves 30 are operatively associated with different steering controls which may suitably be located in single module 34 as shown in Fig. 3, Reference may also be had to Fig. 4 for a complete disclosure of the steering control circuitry and structure and the relationship thereof to the wheel steering structure and other components of this invention, including sensors which will now be described. An ultrasonic sensor 40 is mounted on machine 1 for sensing the location of the string of roadway barrier segments 12 at the front or leading end of the machine . In particular,, the ultrasonic sensor 40 is located at a position forward of inlet 16 and may suitably be mounted on the snout forming the inlet. The ultrasonic sensor 40 is mounted horizontally and. positioned to serially read the distance to a flat vertical face on the roadway barrier segments during movement of the wheeled machine along the string at the first or initial location of the string prior to transport and relocation by the machine . Reading of the distance to the flat vertical face on the head of each barrier segment i done before it is lifted by the conveyor system. The signal produced is compared, with a reference signal and a PLC code processes this information and sends the required signals to the hydraulic proportional valves 30 that steer the wheels to keep the barrier centered relative to the inle , thus steering the machine to follow the wall.

A second sensor, a GPS unit, receives a signal from a satellite system 42 via an antenna 44 mounted on the machine. In the arrangement .illustrated, a fixed base " ^'• TR" (real, time kinematics} unit 48 is used to provide ^■ corrective data from the GPS signal to another antenna 50 on the machine .

The GPS unit has a message output in ASCII format that contains the Cross Track Error information. This error signal represents how far the. machine is from the recorded path or the plotted path, at a ninety degree angle. This signal is mixed with a. differentiated feedback signal representing the wheel angle motion and processed by a PLC code. The result is sent to the proportional hydraulic valves that steer the wheels to keep the machine on the expected path.

The systems work independently to provide the guidance for picking up existing roadway barrier segments and placing them precisely and consistently. The system permits the machine operator or operators to place the barrier in the exact position every transfer without manual inputs to the steering. The system also avoids use of any infrastructure modifications such as above or below grade guide wires or magnetic tape.

To enable the apparatus to reverse direction to return the roadway barrier segments to the original position the antenna (GPS) and ultrasonic sensors would be replicated on both ends of the machine. Figs. 2 and 3, for example, show the ultrasonic sensors 40 projecting from both ends .