Patent Application
20140255096
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 particularly, the invention employs a system for automatically guiding a machine that picks up and places the roadway barrier segments.
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 Vista, Calif. and made available under the Barrier Systems and Quick Change trademarks. Barrier transfer machines are steered and operated either solely by manual control or manual control in conjunction with infrastructure modifications such as above or below grade guide wires or magnetic tape.
As will be discussed in greater detail below, the system of this invention automatically guides a machine that 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 on ultrasonic sensing of some type. Examples of such guidance systems are shown in the following prior art: U.S. Pat. No. 5,549,412, issued Aug. 27, 1996, U.S. Patent Application Pub. No. US 2010/0215433, published Aug. 26, 2010, U.S. Pat. No. 5,052,854, issued Oct. 1, 1991, U.S. Patent Application Pub. No. US 2010/0202829, published Aug. 12, 2010, U.S. Pat. No. 6,220,780, issued Apr. 24, 2001, U.S. Pat. No. 6,022,168, issued Feb. 8, 2000, U.S. Pat. No. 5,253,951, issued Oct. 19, 1993, French Patent No. R2782331A1, issued Feb. 18, 2000 and European Patent No. EP1319757A2, issued Jun. 18, 2003.
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-up barrier segments to relocate the string at the second location.
The invention also encompasses a method of relocating a string of roadway barrier segments disposed end-to-end from a first location 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 picked-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.
Referring now to the drawings, apparatus 10 constructed in accordance with the teachings of the present invention is illustrated. The apparatus moves relative to a string of roadway barrier segments 12 disposed end-to-end at a first location which may, for example, be an off road location. During movement of the apparatus the roadway barrier segments of the string are picked-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 barrier segments at the first location.
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
An ultrasonic sensor 40 is mounted on machine 14 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 is 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 inlet, 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 “RTK” (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.
